ANNUAL REPORTS IN MEDICINAL CHEMISTRY, 1966
LIST O F CONTRIBUTORS
.............
Anderson. G . W Angier. R. B B e r r y m a n . G. H Bicking. J B Biel. J H Bloom. B . M . . . . . . . . . . . . . . . . Bolhofer. W A Buyske. D A Cain. C K Cheney. L . C C h i l d r e s s . S. J . . . . . . . . . . . . . . Cragoe. J r . , E H Dewey. W . L D i a s s i . P. A Dvornik. D Elslager. E F Finger. K F Foye. W 0 Green. J P Hansch. C . . . . . . . . . . . . . . . . . . H a r r i s . L . S. . . . . . . . . . . . . . . . H e r r m a n . J r . , E C. . . . . . . . . Higuchi. T Higuchi. W . I
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296 157 256 59 11 227 91 237 24 102 1 59 33 208 237 131 34G 330 273 347 33 122 340 340
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Hoff. D R J a c o b y . H. I Karnofsky. D A . . . . . . . . . . . Lednicer. D Lerner. L J Levi. R Lewis. A Meltzer. R I Moreland. W T Pappo. R Pinson. R Poos. G I Samter. M S c h a e f f e r . H. J Shen. T Y . . . . . . . . . . . . . . . . Shepherd. R G Sheppard. H S m i s s m a n . E E. . . . . . . . . . . Smith. C G . . . . . . . . . . . . . . . Sonntag. A C Topliss. J . G Ursprung. J . J . . . . . . . . . . . . . Wiegand. R G . . . . . . . . . . . . . Young. C . W
. . . . . . . . . . . . . . . 91 . 166 . . . . . . . . . . . . . . . 199 . . . . . . . . . . . . . . . 208 . . . . . . . . . . . . . . . . . . . 273 . . . . . . . . . . . . . . . . . . 112 . . . . . . . . . . . . . . . 69 . ............ 83 . . . . . . . . . . . . . . . . . . 312 . . . . . . . . . . . . . . . . . 176 . . . . . . . . . . . . . . . . . . 44 . . . . . . . . . . . . . . . . . 256 . . . . . . . . . . . . 304
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217 112 263 321 286 69 48 187 256 166
ANNUAL REPORTS IN MEDICINAL CHEMISTRY, 1966 Sponsored by the Division of Medicinal Chemistry of the American Chemical Society Editor-in- Chief: CORNELIUS K. CAIN McNElL LABORATORIES. INC. FORT WASHINGTON, PENNSYLVANIA
SECTION EDITORS
JOHN BlEL 0 SYDNEY ARCHER 0 LEE CHENEY RICHARD HEINZELMAN IRVING TABACHNICK 0 EDWARD SMISSMAN
ACADEMIC PRESS
New York San Francisco London
A Subsidiary of Harcourt Brace Jovanovich, Publishers
1967
COPYRIGHT 1967, BY ACADEMIC PRESS INC. ALL RIGHTS RESERVED. NO PART OF THlS BOOK MAY BE REPRODUCED IN ANY FORM, BY PHOTOSTAT, MICROFILM, OR ANY OTHER MEANS, WITHOUT WRITTEN PERMISSION FROM THE PUBLISHERS.
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United Kingdom Edition published by ACADEMIC PRESS, INC. (LONDON) LTD. 24/28 Oval Road. London NWI
LIBRARY OF CONGRESS CATALOG CARD NUMBER: 66-26843
PRINTED IN THE UNITED STATES OF AMERICA
PREFACE T h i s i s the second volume of a n annual s e r i e s . The a i m s h a v e not changed f r o m t h o s e s t a t e d p r e v i o u s l y : n a m e l y , to p r e s e n t a c r i t i c a l s u m m a r y of new a n d significant c o n t r i b u t i o n s c o n c e r n i n g v a r i o u s f i e l d s of m e d i c i n a l c h e m i s t r y which a p p e a r e d i n the l i t e r a t u r e during t h e p a s t y e a r . R e a d e r s familiar with t h e f i r s t v o l u m e will n o t i c e s e v e r a l changes. We w e l c o m e a new s e c t i o n e d i t o r a n d s e v e r a l new a u t h o r s . New c h a p t e r s h a v e been added; a few which a p p e a r e d p r e v i o u s l y a r e not r e p r e s e n t e d . Additional c h a n g e s m a y b e expected in f u t u r e volumes, both i n t o p i c s s e l e c t e d f o r d i s c u s s i o n a n d i n viewpoints p r e s e n t ed. All t h o s e who c o n t r i b u t e d to t h e p r e s e n t volume a r e busy people who somehow found time to do additional work. T h e i r e f f o r t s a r e deeply a p p r e c i a t e d . C o m m e n t s of any kind will b e m o s t welcome.
C o r n e l i u s K. Cain
F o r t Washington, P e n n s y l v a n i a J u n e , 1967
V
This Page Intentionally Left Blank
CON T E N TS
............................................ .......................................................
L i s t of Contributors Preface
I.
..
11
v
CNSAGENTS
Section Editor: John H. Biel, Aldrich Chemical Co., Milwaukee, W i s .
1.
........................
Antipsychotic and Anti-anxiety Agents Scott J. C h i l d r e s s , Wyeth L a b o r a t o r i e s , Inc.
1
, Radnor, Pa.
...................
11
2.
A n t i d e p r e s s a n t s , Stimulants, Hallucinogens J o h n H. Biel, Aldrich Chemical Co. , Milwaukee, Wisconsin
3.
Sedatives, Hypnotics, Anticonvulsants, Muscle Relaxants, G e n e r a l Anesthetics 24 Cornelius K. Cain, McNeil L a b s . , Ific., F o r t Washington, Pa.
4.
Analgetics Strong and W e a k . . 33 Louis S. H a r r i s a n d William L. Dewey, Univ. of North Carolina, Chapel Hill, N. C.
5.
Anorexigenic Agents George I. Poos, McNeil L a b s . , I n c . , F o r t Washington, Pa.
........................................
-
..............................
........................................
44
11. PHARMACODYNAMIC AGENTS Section Editor: S. A r c h e r , Sterling-Winthrop Res. I n s t . , R e n s s e l a e r , N. Y.
.....................................
48
............................................
59
6.
Antihypertensive Agents J o h n G. Topliss, Schering Corporation, Bloomfield, N. J.
7.
Diuretic Agents Edward J. Cragoe, J r . and J o h n B. Bicking, M e r c k S h a r p & Dohme R e s e a r c h L a b o r a t o r i e s , West Point, Pa.
8.
Angina P e c t o r i s a n d Antianginal Agents A r c h C. Sonntag and R o b e r t I. M e l t z e r , W a r n e r - L a m b e r t R e s e a r c h Institute, M o r r i s P l a i n s , N. J.
9.
P u l m o n a r y a n d Antiallergy Agents 83 Walter T. Moreland, Chas. P f i z e r & Co., I n c . , Groton, Conn.
10.
.......................
69
............................
...................
Agents Affecting G a s t r o i n t e s t i n a l Functions W i l l i a m A. Bolhofer and Henry I. Jacoby, M e r c k S h a r p & Dohme R e s e a r c h L a b o r a t o r i e s , West Point, Pa. vii
91
111. Section Editor:
CHEMOTHERAPEUTIC AGENTS
L e e C. Cheney, B r i s t o l L a b o r a t o r i e s , S y r a c u s e , N. Y.
11.
A n t i b i o t i c s a n d R e l a t e d Compounds ........................ Lee C. Cheney, B r i s t o l L a b o r a t o r i e s , S y r a c u s e , N. Y.
12.
Synthetic A n t i b a c t e r i a l A g e n t s ............................ 112 R o b e r t G. S h e p h e r d a n d A r t h u r L e w i s , L e d e r l e L a b o r a t o r i e s , A m e r i c a n C y a n a m i d Co. , P e a r l R i v e r , New Y o r k
13.
Antiviral Agents E r n e s t C. H e r r m a n , J r . Ro c h e s t er , Minn e s o t a
14a.
........................................ ,
102
122
Mayo Clinic a n d Mayo Foundation,
Human A n t i p a r a s i t i c A g e n t s .............................. 131 E d w a r d F. E l s l a g e r , P a r k e , Davis a n d Co. , Ann A r b o r , Mich.
..............................
14b.
Animal Antiparasitic Agents 147 Dale R. Hoff, M e r c k S h a r p & Dohme R e s e a r c h L a b o r a t o r i e s Division of M e r c k & C o . , I n c . , Rahway, New J e r s e y
15.
Antifungal A g e n t s R o b e r t B. A n g i e r , L e d e r l e L a b o r a t o r i e s , A m e r i c a n C y a n a m i d C o . , Pearl R i v e r , New Y o r k
16.
Antineoplastic Agents 166 C h a r l e s W. Young a n d David A. K a r n o f s k y , S l o a n - K e t t e r i n g I n s t i t u t e , New York, N. Y.
........................................ ....................................
iV.
METABOLIC DISEASES AND ENDOCRINE FUNCTION
Section E d i t o r : 17.
157
R. V. H e i n z e l m a n , T h e Upjohn Co., K a l a m a z o o , Mich.
......................................
A n t i d i a b e t i c Agents R e x P i n s o n , Chas. P f i z e r & Co.
,
176
I n c . , G r o t o n , Conn.
.........................................
18.
Atherosclerosis 187 J o s e p h J . U r s p r u n g , The Upjohn Company, K a l a m a z o o , Mich.
19.
Reproduction Daniel L e d n i c e r , The Upjohn Company, K a l a m a z o o , Mich.
20.
Steroid Hormones and their Antagonists 208 P a t r i c k A. D i a s s i a n d L e o n a r d J. L e r n e r , T h e Squibb I n s t i t u t e f o r M e d i c a l R e s e a r c h , New B r u n s w i c k , New J e r s e y
21.
Non- s t e r o i d a l A n t i i n f l a m m a t o r y A g e n t s .................... T. Y. Shen, M e r c k S h a r p & Dohme R e s e a r c h L a b o r a t o r i e s Division of M e r c k & C o . , I n c . , Rahway, New J e r s e y
............................................
199
...................
...
Vlll
217
V.
TOPICS IN BIOLOGY
Section E d i t o r : I. I. A. Tabachnick, S c h e r i n g Corp.
,
Bloomfield, N. J.
...........
22.
M o l e c u l a r A s p e c t s of D r u g - R e c e p t o r I n t e r a c t i o n s B a r r y M. Bloom, Chas. P f i z e r & Go., I n c . , Groton, Conn.
23.
F a t e a n d Distribution of D r u g s 237 D. A. Buyske a n d D. Dvornik, A y e r s t L a b s . , M o n t r e a l , Canada
24.
T h e Unknown V a r i a b l e i n S e n s i t i z a t i o n to D r u g s : 256 Drug o r H o s t ? M a x S a m t e r a n d G. H. B e r r y m a n , Univ. of Ill. Col. of Med. , Chicago,Ill. a n d R. G. Wiegand, Abbott L a b s . , No. Chicago, Ill.
2 5.
F a c t o r s Affecting A d r e n a l S t e r o i d o g e n e s i s 263 H e r b e r t Sheppard, R e s e a r c h Dept. , CIBA P h a r m a c e u t i c a l Co. , S u m m i t , New J e r s e y
26.
5-Hydroxytryptamine a n d t h e C e n t r a l N e r v o u s S y s t e m R o b e r t o L e v i a n d J a c k P e t e r G r e e n , D e p a r t m e n t of P h a r m a c o l o g y , C o r n e l l U n i v e r s i t y M e d i c a l College, New York, N. Y.
27.
Regulation of C e l l Metabolism: Role of C y c l i c AMP . . . . . . . . . 286 C h a r l e s G. Smith, The Upjohn Company, K a l a m a z o o , Mich.
227
............................
............................................
................. .......
VI.
273
TOPICS IN CHEMISTRY
Section E d i t o r : E. E. S m i s s m a n , U n i v e r s i t y of K a n s a s , L a w r e n c e , K a n s a s 28.
Synthetic P e p t i d e s G e o r g e W. A n d e r s o n , L e d e r l e L a b o r a t o r i e s , A m e r i c a n C y a n a m i d Company, P e a r l R i v e r , New Y o r k
.......................................
296
29.
N u c l e o s i d e s a n d Nucleotides Howard J. S c h a e f f e r , S t a t e U n i v e r s i t y of New Y o r k a t Buffalo, Buffalo, New York
..............................
304
30.
Steroids Raphael P a p p o , G. D. S e a r l e & Go., Chicago, I l l i n o i s
................................................
312
31.
R e a c t i o n s of I n t e r e s t i n Medicinal C h e m i s t r y . . . . . . . . . . . . . . . 321 E d w a r d E. S m i s s m a n , U n i v e r s i t y of K a n s a s , L a w r e n c e , K a n s a s
32.
A n t i r a d i a t i o n Agents ..................................... W i l l i a m 0. Foye, M a s s a c h u s e t t s College of P h a r m a c y , B o s ton, Ma s s a c h u s ett s
ix
330
VI.
TOPICS I N CHEMISTRY, cont.
......................
33.
P h a r m a c e u t i c s and Biopharmaceutics 340 Takeru Higuchi and Kenneth F. F i n g e r , School of P h a r m a c y , University of Wisconsin, Madison, Wisconsin and W i l l i a m I. Higuchi, School of P h a r m a c y , University of Michigan, Ann A r b o r , Mich.
34.
The Use of Substituent Constants i n Drug D e s i g n . . . . . . . . . . . . 347 Corwin Hansch, Pomona College, Claremont, California
................................................. Compound Name Index. ........................................
Subject Index
X
360
361
Editor:
Section I - CNS Agents John H. Biel, Aldrich Chemical Co., Milwaukee, Wisconsin
Chapter 1. Antipsychotic and Anti-anxiety Agents Scott J. Childress, Wyeth Laboratories, Inc., Radnor, Pennsylvania Introduction - No new antipsychotic or anti-anxiety drugs were marketed in the United States durinn - 1966 and no development of active chemical structures of major novelty was discernible. Compounds that are chemically new but which belong to well-defined active classes are being studied clinically. An enormous amount of work has been reported on mechanisms of central nervous activity, especially the functions of brain amines. Biology - Two symposia1J2 on brain amines have been summarized and another3 has been published in full. A review4 on the metabolism o noradrenaline (NA) in the central nervous system has appeared. Krnjevic has written a useful review on chemical transmission in the central nervous system.
..f
y-Aminobutyric acit (GABA) imitates at least qualitatively a cortical inhibitory transmitter. Brain GABA is increased by meprobamate whereas caffeine causes a decrease.7 These changes are not produced by effects on GABA transaminase or glutamic acid decarboxylase. The anxiety level of dreams has been associated with catecholamine release. 8 Induced emotional stress in rats causes a drop in brain NA but no change in serotonin, GABA or dopamine.9 Manic-depressive patients in a depressed phase have a lowered urinary output of adrenaline, NA and creatinine.lO In a manic phase 3,4-dihydroxyphenylalanine (DOPA) output is elevated. Both reserpine and chlorpromazine (CPZ) cause a much greater increase in homovanillic acid (DOPA metabolite) in the corpus striatum of the mouse than does chlordiazepoxide. Blockade of dopamine receptors is believed to be an important factor in the action of neuroleptics.12 Timsit'3 observes that the cataleptic effect of the butyrophenones is augmented by parasympathomimetics and hindered by atropine. He hypothesizes that these agents bring about an indirect activation of central chulinergic structures. A cholinomimetic effect of CPZ and related compounds that is antagonized by atropine has been 0 b ~ e r v e d . l ~Reserpine and haloperidol, in contrast to CPZ, cause an increase of amine concentrations during the recovery phase of certain cell groups of the lower brain stem possibly as a compensatory mechanism following blockade of transmission.i s A good correlation exists between the ability of a drug to counteract the increase of NA in rat brain caused by a monoamine oxidase inhibitor and the reduction of self-stimulation behavior of chronically-implanted rats. 16
-
Sect. I
2 -
CNS Agents
Biel, Ed.
The functions of the brain amines are intimately associated with the continuing discussion of faulty metabolism as a contributing factor in schizophrenia. The entire question has been freshly reviewed by Kety. l7 The "pink s ot" as a significant indication of schizophrenia has been attacked and its identification with 3,4-dimethoxyphenethylamine has been questioned.21,22 Wagner, et a1.,23 were unable to demonstrate labelled 3,4-dimethoxyphenethylamine or 3,4-dimethoxyphenylacetic acid after treatment of schizophrenics with labelled DOPA although a normal amount of unlabelled acid was found. An exogenous source of normal amounts of this acid is ~uggested.2~It has been shown that 3,4-dimethoxy phenethylamine is not psychogenic in man.25,26 The metabolism of this agent in the rat leads to the corresponding acid (77%).27 The significance of adrenolutin in schizophrenic urine is still debated,28 and other unusual indoles in the urine of mentally retarded patients have been dete~ted.~' A very high rate (10 x normal of metabolism of ascorbic acid by schizophrenics has led Van der Kamp3' to administer high doses therapeutically
.
Another phase of the search for non-behavioral differences between schizo hrenics and non-schizophrenics is concerned with protein fractions. Heath3 has reviewed his proposal that a protein fraction obtained from schizophrenics and called taraxein may be an antibody to brain tissue and schizophrenia may thus be an auto-immune disease. There is an antibody in human plasma that causes stimulation of chicken erythrocyte glycolysis. Ryan, et al.,32 were unable to verify a reported quantitative difference between schizophrenic and normal serum in producing this effect. The level of S19 macroglobulins also proved to be uncorrelated with schizophrenia.33 Conditioned responses in rats were unaffected by injection of schizophrenic serum.34
P
Some reviews on psychopharmacology35,36 and the problems of drug evaluation in man37 and animal& have appeared. A German symp0siurn3~on the subject was published. The effect of sixteen psychotropic agents upon food intake was studied in the rat .4O Phenobarbital, chlordiazepoxide and oxazepam cause increased food intake and a weight gain with the phenothiazines, haloperidol and reserpine causing a weight loss. Avoidance studies in the squirrel monkey show haloperidol almost seven times as potent as CPZ.4I Tolerance to the effects of thioridazine, chlordiazepoxide and tetrabenazine develop in the conditioned rat.42 Amine Depletors - The significance of the observed effects of reserpine and its functional relatives on brain amines is being refined. Rats that have been reserpinized during infancy have a decreased learning ability as adults although the amine depletion is fully di~sipated.~3Reserpine causes an increase in urinary adrenaline and 4-hydroxy-3-methoxymandelic acid but a decrease in NA and DOPA.44 There is some disagreement about the behavioral effects of prenylamine which lowers brain NA and DOPA to roup45 reports muscular weakness as less than 40% of normal values. One 6 finds the compound to be a neurothe only gross effect whereas another leptic agent. Both prenylamine and tetrabenazine give partial protection
t
Chap. 1
Antipsychotic s, Anti-Anxiety Agents
Childres s
-3
against the behavioral and de leting effects of reserpine indicating competition for sites of action.'7 Benzquinamide, on the contrary, enhances both effects of reserpine. Possibly there are highly specific sites that are affected by reserpine with prenylamine and tetrabenazine affecting only less specific but more numerous sites. The enhancing effect of benzquinamide remains obscure. Benzquinamide is approximately equivalent to CPZ as a tranquillizer48 and disrupts conditioned behavior at doses that do not decrease brain NA and serotonin.49 The failure of 2-chlorophenylalanine, a selective depletor of serotonin with little effect on catecholamines,50 to cause sedation suggests that non-s ecific serotonin depletion is not the mechanism by which re3Erpine acts In another a high affinity binding of view, Me0 serotonin by rat-brain nerve terminals is associated with its central action and this binding is inhibited MeO q CH2CHMe2 by reserpine. The depressive effect of several 5-hydroxytryptophan 0 analogs on motor activity in mice does not appear t3 be related to an tetrabenazine effect on serotonin concentration.53 Me X y l ~ p i n i n eis ~ ~a psychoactive compound that resembles tetrabenazice chemically but does not deplete NA. ?eM Ro-4-4602, a decarboxylase inhibitor, has no behavioral effect alone but does augment the behavioral effects benzquinamide of a depletor.55 a-Methyltyrosine, an inhibitor of tyrosine hydroxylase, produces a depression of conditioned responses t at follows a time course similar to that of the observed amine d e p l e t i ~ n . 10-Acetyl ~~ ohimbane (W-2045) has a calming effect in dogs and is anti-hallucinogenic.37
.I1
CONEt-
The metabolism of tetrabenazine proceeds by side-chain hydroxylation, ketone reduction, demethylation of the 9-methoxy group and combinations of the foregoing steps. 58
HO
HO @~H$THNHCOCH(N~)C~OH
Me0
Me eMO&
' xylopinine
RO -4- 4602
,
Phenothiazines and analogs - Bradley, et al. 59 have proposed a neuronal basis for the central action of CPZ: (1) At sites where NA is an excitatory transmitter, CPZ is antagonistic; (2) at inhibitory sites, there is no antagonism, but neuronal depression occurs by other mechanisms such as inhibition of uptake of NA by nerve terminals. The increase of brain phosphatase activity brought about by CPZ may result from the unmasking of normally masked sites of phosphatase action and may have importance in the behavioral effects of CPZ.60 Elevation of melatonin in the tissues is a
Sect. I
4 -
- CNS
Biel, Ed.
Agents
s u g g e s t e d mechanism through which p a r t of t h e e f f e c t of CPZ may be A s t u d y of flavoenzyme i n h i b i t i o n by p h e n o t h i a z i n e s ha achieved. c a r r i e d o u t by examination of t h e i r e f f e c t on D-amino a c i d o x i d a s e . &been
2-Chlorophenothiazine-10-propionic a c i d h a s been i d e n t i f i e d a s a n o t h e r m e t a b o l i t e of CPZ.63 There i s no e f f e c t of dose on t h e e x c r e t i o n p a t t e r n of CPZ.64 The p r i n c i p a l m e t a b o l i t e of Pasaden ( 1 0 - a z e p i n y l p r o p y l 2 - t r i f luoromethylphenothiazine) i s t h e 5-oxide. 65 A d i s c u s s i o n of t h e p r e d i g t i v e v a l u e of animal t e s t s on p h e n o t h i a z i n e s h a s been g i v e n by I r w i n and a comprehensive review of s t r u c t u r e a c t i v i t y r e l a t i o n s h i p s i n t h e t r i c y c l i c compounds was p u b l i s h e d . @
Among t h e new s t r u c t u r e s a t t e n t i o n h a s been f o c u s s e d on t r i c y c l i c compounds o t h e r t h a n p h e n o t h i a z i n e s a l t h o u g h a CPZ a n a l o g made from 3a z a s p i r o [ 5 , 5 ] u n d e c a n e h a s been r e p o r t e d t o be more p o t e n t and much l o n g e r a c t i n g t h a n SPZ.68 P o t e n t a n t i p s y c h o t i c a c t i i t y has been observed w i t h c l o p e n t h i x o l 9, 7' and t h i o t h i x e n e ( P - 4 6 5 7 ~ ) ,7 two t h i o x a n t h e n e compounds. An a c r i d a n e a n a l o g of CPZ, SKF 14,336, i s e f f e c t i v e b u t h a s s i d e - e f f e c t s t o a d e g r e e r e q u i r i n g a n a n t i - P a r k i n s o n agent.T2 H
P
C H C H ~ C H ~ N1 , p4
c l o p e n t h i x o l , %=Cl;
R4= -C%CH20H;
t h i o t h i x e n e , Q= -S02NMe2; %=Me; pinoxepine, Q=Cl; R4= -CH$%OH;
X=S
SKF 14,336
X=S X= -C%O-
S e v e r a l n o v e l t r i c y c l i c compounds have c e n t r a l r i n g s of seven members Numerous p a p e r ~ 7 3 - 7bespeak ~ a c o n s i d e r a b l e i n t e r e s t i n c l o t h i a p i n e (HFIt i s l e a s t e f f e c t i v e i n withdrawn 2159) f o r u s e i n a c u t e psychoses. c h r o n i c s c h i z o p h r e n i c s . Although t h e oxygen a n a l o g (LW 3170) of c l o t h i a p i n e i s more p o t e n t i n producing animal c a t a l e p s y i t i s n o t a s u s e f u l c l i n i c a l l y . 76 Pinoxepine (P-5227)77 i s a n a n t i p s y c h o t i c a g e n t h a v i n g marked s e d a t i v e p r o p e r t i e s b u t producing few e x t r a p y r a m i d a l symptoms. The a n t i d e p r e s s a n t n o r t r i p t y l i n e h a s a s t r o n g s e d a t i v e component and i s an e f f e c t i v e t r a n q u i l l i z e r . 78 N e i t h e r ~ ~ - 7 4 1n o7r ~IBD-7880 g i v e s a t i s f a c t o r y r e s u l t s w i t h c h r o n i c schizophrenics.
HCH2CH2NHMe MK-741 & c l o t h i a p i n e , X=S
LW 3170, X=O
IBD-78
Antip sychotics, Anti-Anxiety Agents
Chap. 1
Childre s s
-5
-
Carbamates Further studies of the recently marketed tybamate have .been reported.81 Ge1ler8* has placed it between meprobamate and CPZ in its psychopharmacological effectiveness. Although it attenuates punishment discrimination at higher doses than meprobamate, it blocks avoidance responding at doses that do not block escape responses. The absence of withdrawal symptoms, previously observed in the dog, has been demonstrated in man.83 Tybamate is metabolized in the dog and rat principally by conversion of its 2-propyl substituent into a 2-hydroxypropyl group. 84 This is accompanied by some N-debutylation. $NOCOC%
83H7 CH20CONHC4Hg I
CH,3 tybamate
F
J333
0
Butyrophenones - K r e ~ p e l *has ~ found triperidol to be the most potent of several well-known 4-fluorobutyrophenones in its effect on the central sympathetic tone. Another butyrophenone (FR33) has been recommend d for the treatment of stuporous catatonia since it causes no sedation.88 The 4-2-chlorobenzyl homolog of haloperidol has a ntore specific effect than haloperidol in the blockade of conditioned avoidance.87
-
Benzodiazepines A supraspinal site of action has been demonstrated for chlordiazepoxide and diazepam as well as for meprobamate.88 The anticonvulsant action of chlordiazepoxide resembles that of dilantin instead of that of acetazolamide, being antagonized by reserpine but not by a-methyl DOPA or a-methyltyrosine.89 This antagonistic effect of reserpine is reduced by a-methyl DOPA, serotonin and amphetamine. The reserpine effect is thus obtained by some means other than its catecholamine-depleting action and the anticonvulsant action of chlordiazepoxi.de is not mediated by catecholamines. N-Demethylation is a newly described metabolic transformation of The effect of dose differchlordiazepoxide in man, the rat and the dog." ences on the observed concentrations of diazepam and its metabolites in the blood and tissues of man has been studied.91 Repeated 30-mg. doses cause a progressiqe rise. The principal (demethylated) metabolite appears after 24 hours, rises until its concentration is comparable to diazepam and persists longer than diazepam after dosing ends. Higher chronically administered doses result in a ratio of metabolite to drug of 2.5 to 1.0. Only traces of 1-methyloxazepam and oxazepam are observed in blood. Tissue storage is indicated by the excretion patterns. Pharmacological and clinical studies have appeared on several unmarketed agents, e.g. prazepam,92 effective against anxiety, and 7-bromo1,3-dihydro-5-(2-pyridyl)-2H-l 4-benzodiazepin-2-oneY93 tested in ambulatory schizophrenics. Schmitt" has reported the unusual 1-chloro derivative (I), obtained by hypochlorite treatment, to be a good sedative. The related compound (11) undergoes a rearrangement on heating to give IV which upon dehydrochlorination with lithium carbonate affords the corresponding cyclohexenyl compound (V). The 7-nitro analog of V has musclerelaxant properties as well as a sedative effect. Treatment of IV with
,
6 -
Sect. I
-
CNS A g e n t s
Biel, Ed.
c1
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R5 IV
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d i b u t y l a m i n e a f f o r d s an isomer (VI) of V, whereas t r e a t m e n t w i t h p y r r o l It i s p o s s i b l e i d i n e r e s u l t s i n replacement of t h e c h l o r i n e t o g i v e V I I . t o i n t r o d u c e as many c h l o r i n e s o n t o t h e a - c a r b o n of t h e 5 - s u b s t i t u e n t a s t h e r e a r e i n i t i a l hydrogen atoms. A f t e r i n t r o d u c t i o n of a second c h l o r i n e atom o n t o I11 t o g i v e VIII, t r e a t m e n t w i t h amines l e a d s t o such p r o d u c t s a s I X . The C-chloro compounds a r e i n g e n e r a l less a c t i v e t h a n t h e Nc h l o r o a n a l o g s a s are t h e compounds having a n amine f u n c t i o n on t h e 5substituent. Another t y p e of benzodiazepine a n a l o g t h a t h a s been r e c e i v i n g a t t e n t i o n a r i s e s from t h e c r e a t i o n of a d d i t i o n a l f u s e d r i n g s by i n t r o d u c t i o n of an e t h y l e n e g 5 o r methyleneg6 b r i d g e between t h e 4 - n i t r o g e n and t h e a d j a c e n t Me 5-phenyl s u b s t i t u e n t found i n most a c t i v e benzodiazepines. Isoquinazepon'7 has been d e s c r i b e d a s having a more s e l e c t i v e e f f e c t t h a n diazepam upon t h e r e t i c u l a r f o r m a t i o n . It p o t e n t i a t e s t h e e f f e c t of DOPA i n c o n t r a s t t o diazepam. Other a n a l o g s have been c o n s t r u c t e d upon a s i m i l a r isoquinazepon p r i n c i p l e by i n t r o d u c i n g a bond o r a
Chap. 1
Antip sychotics, Anti -Anxiety Agents
Childr e s s
7 -
phenyl substituent. bridge between the 6-position and the adjacent Analogs of both chlordiazepoxideg8 and diazepam3' have been made but test results have not been given. Miscellaneous compounds - Although lithium salts have been investigated abroad for many years in the control of manic behavior, their study is just beginning in the United States.100 Lithium ion is effective in phenothiazine-resistant patients but offers little possibility of structural manipulation.10' hidoline is comparable to CPZ in bringing about reduced motor activity but produces much less ata~ia.1~2Methionine sulfoximine gives symptomatic improvement in schizophrenics but is somewhat psychotogenic in controls.103 LL-195 is neuroleptic in the mouse.lO4 Phenygam is a strong depressant that produces slowing of the EEG. lo5 Extracts of cannabis sativa reduce mouse aggressiveness but are ineffective in reducing the toxicity of amphetamine to grouped mice. Oxypertine, which has been marketed in Europe, is approximately equivalent to CPA in blocking conditioned avoidance but is slightly more toxic. " 7 c1 /--=
imidoline
C H HCH CO H 657 2 2
cH2M12 phenygam
oxypertine References
1. T. L. Campbell, Science, 152, 232 (1966). 2. R. J. Wurtman, Science, 154, 680 (1966). 3. U. S. von Euler, S. Rose11 and B. Uvnas, Eds., '?lechanisms of Release of Biogenic Amines," Pergamon, New York, 1966. 4 . J. Glowinski and R. J. Baldessarini, Pharmacol. Rev. 18, 1201 (1966). 5. K. Krnjevi'c, Endeavour, 25, 8 (1966). 6. K. KrnjeviE and S. Schwartz, Nature, 211, 1372 (1966). 7. I. A. Sytinskii and T. N. Priyatkina, Biochem. Pharmacol., 15, 49 (1966). 8. L. A. Gottschalk, W. N. Stone, G. C. Gleser and J. M. Iacono, Science, & 654 (1966). 9. E. L. Bliss and J. Zwanziger, J. Psychiat. Res., 4, 189 (1966)
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10.
- CNS Agents
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2
11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22.
2324. 25 *
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34* 35
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42.
43* 44.
'I
Chap. 1 45.
Antipsychotic s, Anti-Anxiety Agents
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a,383
Childress
9 -
(1965).
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J. R. B o i s s i e r and P. Simon, Therapie, 21, 1491 (1966). G. M. Simpson, J. I q b a l , F. I q b a l and J. W. S . Angus, C u r r e n t Therap. R e s . , & 465 (1966). C. H. C a r t e r , Am. J. Med. S c i . , 251, 465 (1966). 78 A. A. Sugerman, C u r r e n t Therap. Res., & 479 (1966). 79 * 80. D. M. G a l l a n t , M. P. Bishop, W. S h e l t o n and J. G a l l a n t , C u r r e n t Therap. Res., & 351 (1966). 81. S . B. C a l l i s , I n t e r n . J. Neuropsychiat., 3 645 (1966). 47 (1966). 82. I. Geller, J. P s y c h o p h a m a c o l . 354 (1966). 83. H. S . Feldman and M. G. Mulinos, J. New Drugs, 84. J. F. Douglas, B. J. Ludwig, A. S c h l o s s e r and J. Edelson, Biochem. Pharmacol., 15, 2087 (1966). 85. E. Kreppel, A r z n e i m i t t e l - F o r s c h . , 16, 257 (1966). 86. R. Kuhn, M. T a e s c h l e r and J. Schloch, Psychopharmacologia, 3 351 (1966). 87 * N. J. Harper, A. B. Simmonds, W. T. Wakama, G. H. H a l l and D. K. Vallance, J. Pharm. Pharmacol., 18, 150 (1966). 88. S . H. Ngai, D. T. C. Tseng and S . C. Wang, J. Pharmacol. E x p t l . Therap., 153, 344 (1966). 89. J. H. Mennear and A. D. Rudzik, J. Pharm. S c i . , 55, 640 (1966). 90. M. A. Schwartz and E. Postma, J. Pharm. S c i . , 55, 1358 (1966). 91. J. A. F. D e S i l v a , B. A. Koechlin and G. Bader, J. Pharm. S c i . , 55, 692 (1966). E. Kingstone, A. V i l l e n e u v e a n d I. Kossatz, C u r r e n t Therap. Res., 92. & 159 (1966). J . A. F. D e S i l v a and J. Kaplan, J . Pharm. S c i . , 55, 1278 (1966). 93 94. J. Schmitt, French P a t . 1 455 048 (1966). (1966). 95. Sandoz, South A f r i c a n Pa96. Sandoz, B e l g i a n P a t . 6 8 2 , 3 4 3 (1966). 97. J . H. Gogerty, H. O t t , G. O ' N e i l l and J. H. Trapold, F e d e r a t i o n Proc., 25, No. 2, P t . I, 503 (1966). 98. C h r i s t i a e n s , B e l g i a n P a t . 666,355 (1966). 99. A. J. Frey, E. E . G a l a n t a y and H. O t t , U.S. P a t . 3 , 2 9 6 , 2 5 2 (1967). 527 (1966). 100. L. H. Warick, Diseases Nervous System, l01. R. N . Wharton and R. R. Fieve, Am. J. P s y c h i a t . , 123, 706 (1966). 102 W. B. Wright, Jr., H. J. Brabander, R. A. Hardy, Jr., and A. C . O s t e r b e r g , J. Med. Chem., & 852 (1966). R. G. Heath, W. Nesselhof, Jr., a n d E. Timmons, Archiv. Gen. P s y c h i a t , 2 1 4 213 (1966). 104. R. Cahen, A. Boucherle, M. Brunet, J. P e s s o n n i e r and G. Boutet, Ann. Pharm. Franc., 24, 117 (1966). 105. M. N. Maslova and R. A. Khaunina, B u l l . E x p t l . B i o l . Med. (Eng. T r a n s l . ) , 60, 908 (1965). 106. J. S a l u s t i a n o , K. Hoshino and E. A. C a r l i n i , Med. Exptl., 15, 153 (1966). 107. J. M. Abdul Hameed and T. J. Haley, B r i t . J. Pharmacol., 26, 186 (1966).
76. 77.
1,
f
6
Chapter 2 , A n t i d e p r e s s a n t s , S t i m u l a n t s , H a l l u c i n o g e n s John H. B i e l , A l d r i c h Chemical Co., Milwaukee, W i s . I. The A n t i d e p r e s s a n t s
A. I n t r o d u c t i o n - The major developments i n t h e t r e a t m e n t of d e p r e s s i v e i l l n e s s i n 1966 w e r e i n (1) t h e r e c o g n i t i o n of d e f i n a b l e d i s e a s e e n t i t i e s amenable t o s e l e c t i v e d r u g t h e r a p y , ( 2 ) t h e w e a l t h of e x p e r i m e n t a l e v i d e n c e f a v o r i n g t h e m o b i l i z a t i o n of c e n t r a l a d r e n e r g i c pathways as a workable h y p o t h e s i s t o e x p l a i n t h e mechanism of a c t i o n o f t h e c l i n i c a l l y e f f e c t i v e a n t i d e p r e s s a n t s , (3) more s o p h i s t i c a t e d chemical s t r u c t u r e - c l i n icaL a c t i v i t y c o r r e l a t i o n s l e a d i n g t o a much-needed c l a s s i f i c a t i o n of t h e a v a i l a b l e a n t i d e p r e s s a n t d r u g s . T h i s would a l l o w f o r a more r a t i o n a l approach t o t h e d r u g t r e a t m e n t of t h e vari o u s d e p r e s s i o n s and would be based on a c a r e f u l n o s o l o g i c a l diagnosis. The l a t t e r p o i n t is of c r i t i c a l importance i n t h e i n i t i a l s c r e e n i n g of a new a g e n t and i t s u l t i m a t e p l a c e i n a n t i d e p r e s s a n t drug therapy. B.
The Thymoleptic Agents
1, N e w e r S t r u c t u r a l E n t i t i e s
(1) Lu 3-057a
(3) I N 1060
( 2 ) Lu 3-010
(4)
Cyprolidol
(H302
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H3C -\
CH, I
CHC 2H47
0 I
m3 (5)
I
-
( 6) Ciba 30 803Ba
( 7 ) M e 1 i t r ac en
(ELzJq
(8) Dimethacr i n ( I st o n i l
9
Sect. I
12 -
(9)Doxepin p-4599
- CNS A g e n t s
(10) Trimipramine
Biel, Ed.
(11) LA X V I I (Roche)
( S u r m o n t i l81 B u t r i p t y l i n e (Ayerst) Compounds ( 1 ) and ( 2 ) w e r e a c t i v e i n m i c e i n r e s e r p i n e p t o s i s and n o r e p i n e p h r i n e (NE) p o t e n t i a t i o n . Compound ( 2 ) had 2 x potency of p r o t r i p t y l i n e i n t h e s e tests; i t w a s devoid o f l 3 a n t i c h o l i n e r g i c , MAO-inhibitory o r amphetamine-like a c t i v i t i e s The pharmacologic spectrum of cyprol-idol (3) w a s s i m i l a r t o t h a t of imipramine e x c e p t t h a t i t blocked t h e tyramine-induced r i s e i n blood p r e s s u r e o n l y i n a n e s t h e t i z e d dogs b u t p o t e n t i a t e d i t i n c o n s c i o u s do s4-7. I n man, c y p r o l i d o l w a s l e s s e f f e c t i v e t h a n imipramine S t r u c t u r e s ( 4 ) and ( 5 ) d i s p l a y e d moderate a n t i r e s e r p i n e a c t i v i t y i n mice87 9. Compound ( 6 ) a n t a g o n i z e d t h e c e n t r a l s t i m u l a n t e f f e c t s of c a f f e i n and m e s c a l i n e and i n I t s a n t i r e s e r p i n e ef h i b i t e d spontaneous a g g r e s s i o n i n mice. f e c t w a s l e s s t h a n t h a t of imipramine. In f u n c t i o n a l depress i o n s , t h e d r u g w a s q u i t e e f f e c t i v e and r a p i d - a c t i n g (3-6 daysIl-0. Melitracen (7) w a s a sedative-type antidepressant i n man similar t o a m i t r i p t y l i n e . The d r u g w a s a n t i c h o l i n e r g i c and produced f a v o r a b l e e f f e c t s i n 25 o f 38 a t i e n t s and conf u s i o n a l s t a t e s i n 2 of 38 i n d i v i d u a l s l o - 1 1 Dimethacrin ( 8 ) has been e v a l u a t e d q u i t e e x t e n s i v e l y b o t h i n animals12713 and man14-16. I n c l i n i c a l e f f i c a c y and spectrum of s i d e e f f e c t s , t h e d r u g w a s s a i d t o be comparable t o a m i t r i p t y l i n e and imipramine, b u t s u p e r i o r t o p r o t r i p t y l i n e . A high success r a t e w a s obtained i n anxiety depressionsl6. Dimethacrin w a s s y n t h e s i z e d o r i g i n a l l y by Molnar and Wagner-Jaureggl7. Doxepine ( 9 ) , a c e n t r a l l y a c t i v e a n t i c h o l i n e r g i c , a n t a g o n i z e d t h e hy o t h e r mic e f f e c t s of r e s e r p i n e and f i g h t i n g b e h a v i o r i n m i c e P 8 . C l i n i c a l l y , t h e compound w a s n o t as e f f e c t i v e as o t h e r t r i c y c l i c a n t i d e p r e s s a n t s i n t h e t h e r a p y of endogenous d e p r e s s i o n s . Because of i t s h i g h i n c i d e n c e of s e d a t i o n , i t w a s more u s e f u l i n t h e anxious and a g i t a t e d d e p r e s s e d p a t i e n t l g - 2 1 . Trimipramine ( S u r m o n t i l @) i s b e s t c h a r a c t e r i z e d as a n e u r o l e p t i c antidepressant. It d i s p l a y e d good e f f i c a c y i n p s y c h o t i c , anxi o u s and endogenous d e p r e s s i o n s and h e n c e , had a g r e a t e r t h e r a p e u t i c spectrum t h a n imipramine22-25. A p y r i d i n e congener of diazepam (11) e x h i b i t e d b o t h a n t i - a n x i e t y , as w e l l as moodelevating properties i n chronic psychotic patients26.
.
9.
g.
Chap. 2
Stimulants
Biel
13 -
2, Mechanism of Action - I n c r e a s e d s t r i d e s w e r e made toward a r r i v i n g a t a b i o c h e m i c a l bas i s f o r endogenous d e p r e s sion. The argument r u n s somewhat as f o l l o w s : r e s e r p i n e c a u s e s a d e p r e s s i o n i n 15% of t h e p a t i e n t s which cannot b e d i s t i n guished from a t r u e endogenous d e p r e s s i o n . Biochemically, t h i s "model" d e p r e s s i o n i s accompanied by a 50% d r o p i n t h e u r i n a r y e x c r e t i o n of amine m e t a b o l i t e s i n d i c a t i n g t h a t t h e n e u r o t r a n s m i t t e r amines are r e l e a s e d i n t r a c e l l u l a r l y by r e s e r p i n e and m e t a b o l i z e d i n t r a c e l l u l a r l y by MA0 w i t h o u t e v e r e x e r t i n g a p h y s i o l o g i c e f f e c t a t t h e a d r e n e r g i c n e r v e endings27. During t r e a t m e n t w i t h imipramine, u r i n a r y normetanephrine i n c r e a s e d and v a n i l l y l m a n d e l i c a c i d (VMA) Levels d e c r e a s e d s t a r t i n g a t t h e t i m e of t h e p e r i o d of improvement. The d e c r e a s e d VMA e x c r e t i o n i s thought t o b e due t o t h e d e c r e a s e d i n t r a c e l l u l a r d e g r a d a t i o n o f n o r e p i n e p h r i n e (NE) by MA0 brought about by t h e a b i l i t y of t h e a n t i d e p r e s s a n t d r u g s i n p r e v e n t i n g t h e r e uptake of " a c t i v e " ( e x t r a c e l l u l a r ) NE a t t h e c e l l membrane i n t o i n t r a c e l l u l a r storage. The r e - u p t a k e of p h y s i o l o g i c a l l y a c t i v e N E by t h c e l l r e p r e s e n t s one of t h e main pathways of NE i n a ~ t i v a t i o n ~ ~ - E~xlt .r a c e l l u l a r ( " a c t i v e " ) NE i s m e t a b o l i z e d by c a t e c h o l 0 - m e t h y l t r a n s f e r a s e (COMT) t o normetanephr i n e a t t h e a d r e n e r g i c synapse. Schanberg e t a l . 3 2 demonstrat e d t h a t imipramine and d e s i p r a m i n e , b u t n o t chlorpromazine (CPZ) , slowed t h e d i s a p p e a r a n c e of p r e v i o u s l y a d m i n i s t e r e d H3normetanephrine. A d d i t i o n a l e v i d e n c e i s p r o v i d e d by t h e c l a s s i c a l e x p e r i m e n t s of Murad and Shore33 which showqd t h a t p r e t r e a t m e n t of r a t s w i t h f o u r t r i c y c l i c a n t i d e p r e s s a n t s g r e a t l y o t e n t i a t e d t h e a b i l i t y of t e t r a b e n a z i n e t o release metaraminol5 H from a d r e n e r g i c s t o r e s i n h e a r t and b r a i n . Metaraminol i s n o t m e t a b o l i z e d by e i t h e r MA0 or COMT, b u t r e s e m b l e s N E w i t h r e g a r d t o s t o r a g e , relea36 and r e - u p t a k e by t h e a d r e n e r g i c c e l l s , Glowinski e t a l . s t u d i e d t h e e f f e c t s of desmethylimipramine, p h e n i p r a z i n e and amphetamine on t h e d i s p o s i t i o n and metabolism of H3-NE and H3-dopamine i n v a r i o u s r e g i o n s of t h e rat brain. Deaminated m e t a b o l i t e l e v e l s w e r e " s e v e r l y r e d u c e a t w h i l e H3-normetanephrine l e v e l s w e r e " s t r i k i n g l y e l e v a t e d . " Meisch e t a l . 3 5 demonstrated t h a t d e s i p r a m i n e , b u t n o t r e s e r p i n e , can b l o c k t h e P-hydroxylation of 3H-a-methyldopamine and 3Ha-methyltyramine s u g g e s t i n g t h a t h y d r o x y l a t i o n t a k e s p l a c e i n s i d e t h e c e l l membrane, b u t n o t i n t h e r e s e r p i n e - s e n s i t i v e storage sites.
3. S t r u c t u r e - A c t i v i t y R e l a t i o n s h i p s - An e x c e l l e n t and most ComDrehensive t r e a t i s e c o n c e r n i n e t h e c o r r e l a t i o n of chemical- c o n s t i t u t i o n and c l i n i c a l e f z i c a c y of sycho-active d r u g s has been p u b l i s h e d by S t a c h and PtJldinger56. I n r e g a r d t o t h e t r i c y c l i c a n t i d e p r e s s a n t d r u g s , t h e "skewed" c h a r a c t e r of t h e f u s e d r i n g system, t h e e f f e c t of r i n g s u b s t i t u e n t s , t h e n a t u r e of t h e aminoaLkyl s i d e c h a i n , as w e l l a s t h e s i z e of t h e middle r i n g are d i s c u s s e d i n r e l a t i o n t o t h e potency and t y p e of a c t i o n of t h e r e s u l t i n g a n t i d e p r e s s a n t d r u g s . Peldinger37 has c l a s s i f i e d t h e c u r r e n t l y a v a i l a b l e t r i c y c l i c d r u g s
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a c c o r d i n g t o t h e i r c l i n i c a l s p e c t r a and c h e m i c a l s t r u c t u r e s : (,m2) gN\ 0 CHCH, I. Mood-elevat i n g 3 I
a?I
3N/EHHi
( CH2 1
m3 Dibenzepine ( N o v e r i l @ )
Imipramine I I. Ant i - a n x i e t y and Ant i -ag it a t i o n P r o p e r t i e s 5-1Ant i d e p r e s s a n t s
I
m 2 C H (CH3) CH2N, A m i t r i p t y 1i n e
/
CH3 CH3
T r imipramine
111, S t i m u l a n t A n t i d e p r e s s a n t s - The s t r u c t u r e s shown below, as w e l l as t h e MA0 i n h i b i t o r s a r e used i n t h e i n h i b i t e d , withdrawn ( a n e r g i c ) depressed p a t i e n t s . They a l s o have a g r e a t e r t e n dency t o e x a c e r b a t e p s y c h o t i c symptoms:
D e s ipramine IV.
Nortriptyline
N e u r o l e p t i c s w i t h Mood-elevating
0pi p ra m 0 1
Pro t r i p t y l i n e
Properties
Chap. 2
Stimulants
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C . C l i n i c a l C o n s i d e r a t i o n s - One of t h e most v e x i n g problems i n the p a s t has been how t o r e c o g n i z e p o t e n t i a l a n t i d e p r e s s a n t a c t i v i t y of a new d r u g i n animals, e s p e c i a l l y when s u c h a d i s e a s e e n t i t y i s presumably n o n - e x i s t e n t i n t h e animal kingdom and m e n t a l d e p r e s s i o n i t s e l f i s s u c h a mosaic d i s ease syndrome i n man. PUldinger37 h a s l a i d down c e r t a i n pharmacologic c r i t e r i a which t h e p r e s e n t l y a v a i l a b l e thymolept i c s have f u l f i l l e d and which d i s t i n g u i s h them from t h e neurol e p t i c s , c e n t r a l s t i m u l a n t s , and MA0 i n h i b i t o r s :
Stimulants Reserpine Antagonism
functional
:
anticatal. potentiate adren Functions
biochem.
functional
anticatal. anticatal
-
Principal Auton. E f f e c t s I
Thymoleptics N e u r o l e p t
I
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E f f e c t s on R e t i c u l ,Form1 n
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anticholin.
.
.
adrenolytic
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.
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.
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Obviously, t h i s s p e c t r u m of pharmacologic a c t i v i t i e s has been d e r i v e d p o s t f a c t o from t h e p r o p e r t i e s of t h e t r i c y c l i c a n t i d e p r e s s a n t s and i t w i l l b e i n t e r e s t i n g t o see w h e t h e r i t w i l l be u s e f u l i n p r e d i c t i n g c l i n i c a l a n t i d e p r e s s a n t a c t i v i t y of t o t a l l y u n r e l a t e d s t r u c t u r e s . Another problem w h i c h has b e s e t the c l i n i c a l i n v e s t i g a t o r h a s been t h e c o n f u s i o n as t o w h a t c o n s t i t u t e s a p r i m a r c l i n i c a l d e p r e s s i o n . A r e c e n t l y p u b l i s h e d p a p e r by M i l l e r 3 g goes f a r i n l a y i n g down g u i d e l i n e s f o r t h e d i a g n o s i s of endogenous d e p r e s s i o n and i s "must" r e a d i n g f o r anyone working i n t h e area of m e n t a l d e p r e s s i o n . The main p o i n t s M i l l e r makes are t h e following : ( 1 ) Endogenous d e p r e s s i o n i s a d e f i n i t e c l i n i c a l ent i t y of o r g a n i c ( p a t h o p h y s i o l o g i c ) o r i g i n , ( 2 ) I t a f f e c t s a s t a b l e s u b j e c t w i t h a p r e v i o u s l y good p e r s o n a l i t y h i s t o r y , whereas r e a c t i v e d e p r e s s i o n af f e c t s the u n s t a b l e and i n a d e q u a t e p e r s o n a l i t y . ( 3 ) Endogenous d e p r e s s i o n s t r i k e s "out of t h e blue" w i t h no a p p a r e n t environmental causes, a l t h o u g h endoc r i n e c h a n g e s , prolonged v i r a l i n f e c t i o n s , h e p a t i t i s and mononucleosis may a t t i m e s p r e c e d e i t . ( 4 ) I t i s c h a r a c t e r i z e d by e a r l y morning awakening and p r o g r e s s i v e improvement as t h e d a y goes on, as w e l l as by c o n s t i p a t i o n , l o s s of b o t h a p p e t i t e and sexual i n t e r e s t . ( 5 ) Endogenous d e p r e s s i o n r e s p o n d s r e a d i l y ( i n 75% of the c a s e s ) t o ECT and d r u g t h e r a p y , whereas r e a c t i v e d e p r e s s i o n s a r e o f t e n r e s i s t a n t t o d r u g I t i s lla p h y s i c a l i l l n e s s t r e a t a b l e by phytherapy. s i c a l means". Both P U l d i n g e r l g and H o l l i s t e r e t a1 -39
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p o i n t t o t h e c r u c i a l importance of n o s o l o g i c a l d i a g n o s i s i n t h e e v a l u a t i o n of a new a n t i d e p r e s s a n t , s i n c e o n l y t h e improvement i n endogenous and i n v o l u t i o n a l d e p r e s s i o n s i s the criterion for c l a s s i f y i n g a new d r u g as an a n t i d e p r e s s a n t . Chlorpromazine i s a c t i v e i n r e a c t i v e and s c h i z o p h r e n i c d e p r e s s i o n s , b u t i n a c t i v e i n endogenous depressions. 5. Combination Therapy - Th c o m b i n a t i n of a m i t r i p t y l i n e a d perphenazine ( T r i a v i l & , Etrafon h a s been a p p l i e d p r i m a r i l y i n t h e t h e r a p y of r e a c t i v e , a n x i e t y and p s y c h o t i c d e p r e s s i o n s . While most r e p o r t s w e r e f a v o r a b l e , H o l l i s t e r e t a l . 4 1 c o u l d n o t confirm t h e s u p e r i o r i t y of t h e combination o v e r a m i t r i p t y l i n e a l o n e i n r e t a r d e d or anxious d e p r e s s i o n s . The a d d i t i o n of an MA0 i n h i b i t o r ( p h e n i p r a z i n e ) t o a chlorpromazine regimen i n c h r o n i c w i t h drawn s c h i z o p h r e n i c s r e s u l t e d i n s i g n i f i c a n t improvement l e a d i n g t o a d i s c h a r g e of 60% of t h e p a t i e n t s who had been h o s p i t a l i z e d f o r many y e a r s on j u s t t r a n q u i l i z e r t h e r a p y alone42. S a r g a n t e t a1.42 r e p o r t on a s e r i e s of 7 3 p a t i e n t s r e f e r r e d t o t h e a u t h o r s f o r leucotomy because of i n t r a c t a b l e chronic tension. The a d d i t i o n of i p r o n i a z i d t o t h e p r e v i o u s l y u n s u c c e s s f u l regimen of a m i t r i p t y l i n e , n a r c o s i s and ECT nece s s i t a t e d leucotomy i n o n l y 18 of t h e 7 3 p a t i e n t s , 6 . S i d e E f f e c t s of A n t i d e p r e s s a n t Drugs - Recent p u b l i c a t i o n s p e r t a i n i n g t o t h e c L i n i c a l s i d e e f f e c t s of a n t i d e p r e s s a n t a g e n t s are by H o l l i s t e r 4 4 , Kahr e t a'L.45, Tschen e t a l . 4 6 , B l a i r and Simpson47 and Simpson e t a l . 4 8 . The t o x i cology of a m i t r i p t y l i n e h a s been d e s c r i b e d by Myers e t a1.49.
8)
7. Imipramine M e t a b o l i t e s - The desmethyl- (DMI) and t h e 2-hydroxyimipramine a r e t h e major m e t a b o l i t e s of imipramine. I n a d d i t i o n s i x t e e n o t h e r s have been d e t e c t e d i n r a t L i v e r microsomes50, Theobald e t a l . 5 1 have r e p o r t e d on t h e c e n t r a l and p e r i p h e r a l e f f e c t s of s i x imipramine m e t a b o L i t e s i n s e v e r a l animal s p e c i e s . C. MA0 I n h i b i t o r s
1. N e w e r S t r u c t u r e s o-Cl!ifOC2H4NH~
$CH2NC0 2C 2H
A
C g H l l - T 2
Chap. 2
Stimulants
Biel
17 -
Pargyline
QXJ
@-CH ( c H ~N) H - N H ~
I
(19) Mebanazine (I.C.1.) H CH3 Compound ( l 2 ) , a p o t e n t MA0 i n h i b i t o r , caused s c h i z o p h r e n i c p a t i e n t s t o become o v e r a c t i v e , i r r i t a b l e , more psyc h o t i c and a g g r e s s i v e . These e f f e c t s are c h a r a c t e r i s t i c of most s t i m u l a n t - t y p e a n t i d e p r e s s a n t s , i n c l u d i n g t h e thymolept i c drugs. P a r a d o x i c a l l y , t h i s compound a l s o produced s e d a t i o n and an i n c r e a s e i n s l e e p 5 2 . Compound (13) proved t o b e e f f e c t i v e i n a small number of newly a d m i t t e d d e p r e s s e d patients. Although l e s s e f f i c a c i o u s t h a n a m i t r i p t y l i n e , i t appeared t o have a lower i n c i d e n c e of s i d e e f f e c t s 5 3 . While (14) produced MA0 i n h i b i t i o n i n a n i m a l s compar b l e t o t h e phenyl d e r i v a t i v e and t r a n y l c y p r o m i n e ( P a r n a t e , t h e a d d i t i o n of a methyl group i n s t r u c t u r e ( l 5 ) a b o l i s h e d a c t i v i t y 5 4 , 55. S h i f t i n g of t h e N-propargyl group i n p a r g y l i n e i n t o t h e a l k y l e n e s i d e c h a i n produced a compound (16) e q u a l t o p a r g y l i n e i n unmasking t h e CNS s t i m u l a n t e f f e c t s of P-phenethylamine i n mice. However, t h i s a g e n t w a s much s h o r t e r - a c t i n g which would A s an t e n d t o i n d i c a t e a r e v e r s i b l e - t y p e o f MA0 i n h i b i t i o n . o v e r t CNS s t i m u l a n t , t h e d r u g had 1/25 t h e a c t i v i t y of amphetamine56. The t e t r a h y d r o n a p h t h y l a n a l o g of p a r g y l i n e ( 1 7 ) had 20 t i m e s t h e a c t i v i t of t h e l a t t e r i n mice57. A " c y c l i z e d " d e r i v a t i v e (18) produced r e s e r p i n e ree t r y p t a m i n e (Monase v e r s a 1 and MAO-I i n mice a t 50 mg/kg58. Mebanazine (Actomol@) (19) i n animals i s clatmed t o be a more p o t e n t MAO-I t h a n p h e n i p r a z i n e w i t h a g r e a t e r t h e r a p e u t i c index59. The d r u g appeared t o be "devoid of s p e c i f i c a n t i d e p r e s s a n t e f f e c t s " i n man, b u t a t d a i l y d o s e s of 30 mg i t p r e c i p i t a t e d a " s e v e r e and prolonged h y p o t e n s i v e c o l l a p s e " i n 3 o f 7 p a t i e n t s . I n d i a b e t i c s on i n s u L i n t h e r a p y , t h e d r u g caused a spontaneous hypoglycemic response60. The a d d i t i o n of an MAO-I t o a n e u r o l e p t i c d r u g regimen i n a n e r g i c withdrawn p s y c h o t i c s w a s d i s c u s s e d i n t h e previous section. (18)
(4
4
The " F a l s e N e u r o t r a n s m i t t e r " c o n c e p t as a b a s i s f o r e x p l a i n i n g t h e mechanism of t h e h y p o t e n s i v e a c t i o n of MAO-1's The d e l a y e d i s p r e s e n t e d i n g r e a t e r d e t a i l by Cohen e t a l . 6 1 . a c t i o n of t h e MAO-1's w i t h r e s p e c t t o t h e i r c l i n i c a l a n t i d e p r e s s a n t and h y p o t e n s i v e a c t i v i t i e s i s presumably due t o an i n d i r e c t e f f e c t dependent on t h e g r a d u a l a c c u m u l a t i o n of mono amines a t t h e a d r e n e r g i c n e r v e f i b r e s . According t o t h e
18
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e x p e r i m e n t s of C a r l s s o n and Waldeck62, 3H-metaraminol i s r e l e a s e d o n l y s l o w l y by t h e MAO-1's from t h e n e r v e f i b r e s . T h i s e f f e c t can b e blocked by d e c a r b o x y l a s e i n h i b i t o r s which p r e v e n t monoamine format i o n .
11. C e n t r a l S t i m u l a n t s A. New S t r u c t u r e s @CH- C2H4NMe2 4
C6H11
OH
(Win 1344)
(20) Gamfexine
(21)
(U-23,807A)
Win 1344 (20) w a s c a p a b l e of s t i m u l a t i n g d e p r e s s e d patients. I n combination w i t h t h i o r i d a z i n e , it worked w e l l i n withdrawn s c h i z o p h r e n i c s 1 3 . Gershon e t a1.64 found t h e compound l e s s e f f i c a c i o u s t h a n imipramine (37 v s 54%). The s t i m u l a n t p r o p e r t i e s of t h e d r u g o f t e n r e s u l t e d i n exacerb a t i o n of p s y c h o t i c symptoms. Compound ( 2 1 ) had 1/3 t h e a c t i v i t y of amphetamine i n i n c r e a s i n g spontaneous motor a c tivity. The e f f e c t s of s i n g l e o r a l d o s e s i n c a t s and dogs w e r e s t i l l p r e s e n t a f t e r o 2 4 hours. Unlike amphetamine, U-23,807A lowered body T and p o t e n t i a t e d h e x o b a r b i t a l and e t h a n o l n a r c o s i s a t two and f o u r t i m e s t h e d o s e of c h l o r promazine, r e s p e c t i v e l y 6 5 . The b r a n c h i n g of t h e a l k y l e n e s i d e chain v i r t u a l l y eliminated a l l per ipher al anticholiner g i c effects. The s y n t h e s i s of t h i s series has been d e s c r i b e d by M o f f e t t e t a l , 6 6 and t h e pharmacology by KeasLing e t aL67. The &isomer i s now undergoing c l i n i c a l t r i a L . Magnesium pemoline w a s b r i e f l y a l l u d e d t o i n t h e 1965 "Annual R e p o r t s of M e d i c i n a l Chemistry" (page 23) as promoting t h e b i o s y n t h e s i s of RNA i n r a t b r a i n and f a c i l i t a t i n g l e a r n i n g by i n c r e a s i n g memory and r e t e n t i o n of l e a r n e d b e h a v i o r . Subs e q u e n t r e p o r t s have made t h e s e f i n d i n g s c o n t r v e r s i a l and f o r furthe reader i s referred t o the cited t h e r g u i d a n c e on t h i s s u b j e c t .
reference^^^-^^
T h e mechanism of t h e c e n t r a l a c t i o n of amphetamine cont i n u e s t o b e e x p l o r e d and t h e p r e v a i l i n g e v i d e n c e p o i n t s t o muLtiple mechanisms i n v o l v i n g c a t e c h o l a m i n e r e l e a s e , i n h i b i t i o n o f c a t e c h o l a m i n e u p t a k e , MA0 i n h i b i t i o n and a d i r e c t i n t r i n s i c action73-75. Dependence on amphetamine and o t h e r s t i m u l a n t d r u g s , its c l i n i c a l m a n i f e s t a t i o n s and t r e a t m e n t a r e t h e s u b j e c t of two e x c e l l e n t reviews76,77.
XXI. The H a l l u c i n o g e n s A. P s y c h e d e l i c Therapy - The i n c r e a s e d u s e o f p s y c h e d e l i c C'mind expanding") d r u g s i n p e r s o n a l i t y d i s o r d e r s p r o b a b l y r e p r e s e n t s one o f t h e more i m p o r t a n t developments i n t h i s area. Thus, Leuner78 found t h e s e d r u g s a n " e x c e l l e n t a d j u v a n t " i n t h e p s y c h o t h e r a p y of c h a r a c t e r n e u r o s e s , p s y c h o p a t h i c
Chap. 2
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19 -
p e r s o n a l i t i e s , n e u r o t i c d e p r e s s i o n s , a n x i e t y n e u r o s e s and h y s t e r i c c o n v e r s i o n symptoms which d i d n o t y i e l d t o any o t h e r form of t r e a t m e n t . Remissions w e r e o b t a i n e d i n 76% of t h e cases. M a l i t z 7 9 found 0.07 mg of LSD e q u i v a l e n t t o 500 mg of m e s c a l i n e i n f a c i l i t a t i n g t r a n s f e r e n c e d u r i n g psychotherapy. Alcoholism w a s a r t i c u l a r l y amenable t o t h i s t y p e of t h e r a p y . Savage e t al.gO o b t a i n e d s i m i l a r r e s u l t s as t h e two p r e v i o u s i n v e s t i g a t o r s i n p a t i e n t s d e m o n s t r a b l y low i n m o t i v a t i o n , socio-economic s t a t u s and e d u c a t i o n a l l e v e l . V a r i a b i l i t y i n r e s p o n s e w a s due t o p e r s o n a l i t y , p r e v i o u s h i s t o r y of t h e p a t i e n t , and t h e p a r t i c u l a r t h e r a p e u t i c environment. BenderS1 found i t e a s i e r t o b r e a k t h r o u g h t h e a u t i s t i c ( s e l f - c e n t e r e d ) b e h a v i o r of s c h i z o p h r e n i c c h i l d r e n w i t h t h e u s e of LSD. Abramson82 h a s r e viewed t h e a p p l i c a t i o n of LSD, p s i l o c y b i n , p e y o t e , m a r i j u a n a i n psychotherapy. The d a n g e r s of LSD i n g e s t i o n i n a nont h e r a e u t i c environment have been summarized by Cohen83 and F i n k 8f: Emotionally l a b i l e p e r s o n s w e r e p a r t i c u l a r l y susc e p t i b l e t o t h e p s y c h o t o g e n i c p r o p e r t i e s of t h e d r u g . The p h e n o t h i a z i n e t r a n q u i l i z e r s minimized s u c h r i s k s , i f , a d m i n i s t e r e d as soon as t h e a c u t e LSD syndrome had been observed84.
.
B. Endogenous H a l l u c i n o g e n s - The s u b j e c t of abnormal amine metabolism i n s c h i z o p h r e n i c s w a s reviewed i n t h e 1965
"Annual R e p o r t s of M e d i c i n a l Chemistry" ( p a g e 2 5 ) . H o l l i s t e r and F r i e d h o f f 8 5 w e r e u n a b l e t o produce any e f f e c t s i n v o l u n teers w i t h DMPEA (3,4-dimethoxyphenethylamine), whereas m e s c a l i n e i n similar d o s e s produced profound e f f e c t s of d e p e r s o n a l i z a t i o n and p e r c e p t u a l d i s t o r t i o n . DMPEA i s m e t a b o l i z e d mainly t o 3,4-dimethoxyphenylacetic a c i d , whereas m e s c a l i n e i s e x c r e t e d l a r g e l y unchanged86. H e l l e r 8 7 found t h a t t h e a d m i n i s t r a t i o n of -0-1's t o schizophrenics exacerbated t h e i r p s y c h o t i c symptoms and produced e x c r e t i o n of a "bufot e n i n - l i k e " s u b s t a n c e . O t h e r i n v e s t i g a t o r s have been u n a b l e t o confirm s u c h f i n d i n g s of abnormal amine metabolism i n s c h i z ophr en i c s -go. C. Anticholinergic Hallucinogens ( C l i n i c a l E f f e c t s ) Neubauer e t a l , Y L c l a i m t h a t antagonism t o D i t r a n may r e q u i r e b o t h a d r e n o l y t i c and c h o l i n o m i m e t i c a c t i v i t i e s . Bauerg2 and FLiigel.93 w e r e a b l e t o i n h i b i t t h e psychotomimetic e f f e c t s of Bayer 1443 and D i t r a n by t h e p r i o r a d m i n i s t r a t i o n d i h y d r o ergotamine. I n c r e a s e d u r i n a r y e x c r e t i o n of c a t e c h o l a m i n e and s e r o t o n i n m e t a b o l i t e s a f t e r t h e a d m i n i s t r a t i o n of N-methyl-3p y r r o l i d y l phenylcyclopentylglycolate w a s d e m o n s t r a t e d by Bente e t D. Pharmacologic and Biochemical E f f e c t s - The f i n d i n g bv Brown e t a l . 9 3 t h a t t h e a c u t e a d m i n i s t r a t i o n o f c h l o r p>omazine (CPZ) and D i t r a n produced a d e e p coma i n dogs and t h a t t h e s u b s t i t u t i o n of CPZ by imipramine e l i c i t e d a much m i l d e r r e s p o n s e might p o s s i b l y b e e x p l o i t e d as a s c r e e n i n g test f o r novel psychotropic drugs.
20
Sect.
I - CNS A g e n t s
B i e l , Ed.
In an effort to elucidate the mechanism of action o f psychotomimetic g‘lycolate esters, Rogeners et a1.96 studied the action of Ditran on the surface pressure and viscosity of lecithin mono-layers. Their findings indicate that Ditran might be associating with the phosphate group and the fatty acid chains of lecithin. The drug forms associations with calcium and phosphate ions and with ATP. Votava et a1. 97 found no pharmacological or behavioral differences in animals with LSD and a number of its congeners. In man, only LSD caused psychic disturbances. On a biochemical basis, a distinction could also be made in that only LSD caused a rise in serotonin plasma ‘Levels. References 1. P.V.Petersen, N.Lassen, V.Hansen, T.Huld, J.Hjortkjaer, J. Holmblad, I.Mo11er Nielsen, M.Nymark, V.Pedersen, A.Jorgensen and W.Hougs, Acta Pharmacol.Toxico1. 24, 121 (1966). 2. P.V.Petersen, N.Lassen, V.Hansen,T.Hxd, J-Hjortkjaer, J. Holmblad, I.Mo11er Nielsen, M.Nymark, V.Pedersen, A.Jorgensen and W.Hougs, Acta Pharmaco1.Toxicol. 24, 126 (1966). 3. A.CarIsson, K.Fuxe, B.Hamberger andM.Lindquist, Acta Physio1. Scand., 67, 481 (1966). 4. B.Koro1, M.L.BrZn& I.W.Sletten, Curr.Therap.Res., 8, 543 (1966). 5. M.L. Brown, S.Gershon & B. Koro1 , Med. Pharmaco1.Expt1.15, 329 (1966). 6. B.Koro1, W.J.Lang, M.L.Brown & S.Gershon, Nature, 209, 1249 (1966). 7. L. J.Hekimian, S .Gershon & A.F1oyd, J. PsychopharmacoL ,in press. 8. Y .M. Batulin, T.A, K1ygu1 , A. E,Kovaleva, I. B. Fedorova & L.A. Aksanova, Farmako1.i Toksikol.,E, 590 (1966). 9. D.Mu1der &C.J.Van Eeken, Arch.int.Pharmacodyn,162,497 (1966). 10. K.A.FlUge1, R.Stoerger &Th.VeiI, Arzneimittel-Forsch.15, 1392 (1965). 11. D.Bente, M.P.EngeLmeier, K.Heinrich, H.Hippius &W.Schrnitt, Arzneimittel-Forsch,16, (2a), 319 (1966). (2a) lla.W.Bister, M.Kri11 &R.WunderIe, Arzneimittel-Forsch.,g, ,119 (1966). llb.W.PWdinger, Therapeutische Umschau, 23, 376 (1966). 12, U.Jahn, Arch. Exp.Path.Pharmako1.,25348 (1966). 13. U. Jahn and G.HausIer, Wien.KIin.Wochschr ’-78, 21 (1966). 14. E.Guth&G.Hoffmann, Wien.KIin.Wochschr * ’-78, 14 (1966). 15. S.Taen and W.Pdldinger, Schweiz.Med.Wochschr.,96,1616(1966). 16. F.J.Ayd, 1ntern.Drug Therapy News Letter,11,(1=7). 17. I.Mo1nar and Th. Wagner-Jauregg, He1v.ChirActa 48,1782(1965). 18. A.Ribbentrop and W.Schaumann, Arzneimittel-Forsc~15,86-3l963. 19. W .P81dinger , J. Angs t , F. Cornu,P.Dick and H .HeimannTArzne imittel-Forsch. 16, 650 (1966). 20. G.M.Simpson, Salim, Curr.Therap.Res.7, 661. (1965). 21. W.PUldinger, Nervenarzt, 37, 121 (1966):
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22. Editorial, Brit.Med.J. 1967, I, 98. 111, 1155 (1965). 23. B.H.Burns, Brit.J.Psych?at., 24. M.M.SaIzmann, Brit.J.Psychiat, 111, 1105 (1965). 25. L-GayraL, R.Puyue1o and G.Roux, Therapie,20, 639 (1965). - 411 (1966). 26. E.Stonehi11, H.Lee, T.A.Ban, Dis.Nerv.Sysr27, 27. Editorial, The Lancet, I, 317 (1967). 28. J.Schildkraut,E.K.GordoK and J.Dure11, J.Psychiat.Res.3, 213 (1965). 29. J.Glowinski, L.L.Iversen&J.Axelrod, J.Pharmaco1.Exp. Therap. ,151, 985 (1966). 30. A-Car'Lsson and B.WaIdeck, Acta PhysioL.Scand.67,417(1966). 31. Editorial, Science, 154, 1058 (1966). 32. S.M.Schanberg, J. J.SE1dkraut and I. J.Kopin, Biochem. Pharmacol.16, 393 (1967). 33. J.E.Murad and P.A.Shore, Int.J.Neuropharmaco1.5,299(1966). 34. J.Glowinski, J.Axe1rod and L.L. Iversen, J. Pharmaco1.Exp. Therap. 153, 30 (1966). 35. J.J.Meisch, A.Car1sson and B.WaIdeck, J.Pharm.Pharmaco1. 19, 63 (1967). 36. K.Stach & W.PULdinger,Prog.Drug Res. 9, 129 (1966). 37. W-PUldinger, Wiener Zeitschr.Nervenhzi1kunde und deren Grenzgebiete XXIV, 128 (1966). 38. H.Miller, Brit.Med.J., 1967, 1, 257. 39. L.E.HoIlister, J.E.Overa11, M.H.Johnson, J.SheIton, I. Kimbell and A.Brunse, J.Nerv.Ment.Dis.142, - 460 (1966). 40. Literature Review, Curr.Therap.Res.9, 89 (1967). 41. L.Ho1~ister,J.E.Overa11,M.H.Johnson~J.She1ton,I.Kimbe11 and A.Brunse, J.Nerv.Ment.Dis.142, 460 (1966). 42. L.Bucci, Dis.Nerv. Syst.28, r(1967). 43. W.Sargant,C.J.S.Walter and N.Wright, Brit.Med.J.,1966,1,322. 44. L.E.Hollister, J.Am.Med.Assoc.196, - 411 (1966). 45. H.Kahr, R.Battegay and W.Ptjldinger, Arzneimittel-Forsch. 16, 242 (1966). 46. P.Tschen, A.Weatherhead and N.G. Richards, New Eng1. J.Med. 274, 1197 (1966). 47. J.H.Blair and G.M.Simpson, Dis.Nerv.Syst.27, 645 (1966). 48. G.M. Simpson, J.H. Blair and D.Amuso, Dis.N=v. Syst. 26, 787 (1965). 49. D.B.Meyers, R.M.Smal1 and R.C.Anderson, ToxicoL.App1. Pharmacol. 9, I52 (1966). 50. M.H.BickF1 and M.Baggiolini, Biochem.Pharmaco1.15,1155(1966). 51. B.W.Theobald,H.A.Kunz and G.Monpurgo, Med.PharmzoL.Fxpt1. 15, 187 (1966). 5 2 . G.M.Simpson, J.Iqba1 and I. Iqbal, Curr. Therap.Res.8,400(1966). 53. T.A.Ban, A.St.Jean and H.E.Lehman,Curr.Therap.Res.3,614(196@. 54. J.Finkelstein, E.Chiang, F.M.Vane and J.Lee, J.MedTChem. 9 , 319 (1966). 53. J-Finkelstein, E.Chiang and J.Lee, J.Med.Chem. 9, 440 (1966). 56. A. Burger, S. E. Zimmerman and E. J.Ari@ns, J.Med .CEem. 9, 459 ('66). 57. C.F.Huebner, E.M.Donoghue, A. J.Plummer and P.A.Furness, J. 9, 830 (1966). Med.Chem. -
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58, Y .G ,Perron, W .F .Minor, M .E .Bierwagen, S .A.Ridlon and M .H. P i n d e l l , J.Med.Chem. 9,136(1966). 59. A S p i n k and B.A.Whittle, I n t .J.Neuropharmacol.5,125(1966), 60. A.J.Cooper, I n t .J.Neuropsychiat .$,342(1966). 61. R.A.Cohen, I .J.Kopin, C .R.Crevellng, J.Musacchio, J . E . F i s c h e r , J .R .Crout and J . R . G i l l , Ann.Int .Med .=,347(1966). 62. A.Carlsson and B.Waldeck, A c t a Physiol.Scand.67,471(1966). 63 B .C S c h i e l e , L.M.Tredici and R.L.Zhmerman, C G r .Therap. R e s .t3,565(1966). 64. S .Gershon, L .J .Hekimian and A .Floyd, C l i n . Pharmacol (1966)223. 65. H.H,Keasling, R . J . C o l l i n s and W.Veldkamp, Pharmacologist, 8(1966). 65. R.B.Moffett, L.L.Skaletzky, R.E.Strube and T,L.Pickering, Am.Chem.Soc .Abstr.Papers, 152nd Meet. ,N.Y. , N .Y. ,Sept -12,1966. 67. H.H.Keasling, R . J . C o l l i n s and W.Veldkamp, Pharmacologist, 8(1966). 681 N . R M o r r i s , G .K.Aghajanian and F .E .Bloom, S c i e n c e ,155, 1125(1967). 155,1281(1967). 69. P.W,Frey and V.J.Polidora, Science 155,603(1967). 70. R.G.Smith, S c i e n c e 153,902(1966). 71. R-Bowman, S c i e n c e 72. B.L.Welch, S c i e n c e L55,849(1967). 7 3 . J.H.Mennear and A.D.Rudzik, L i f e S c i . 5,349(1966). 74 , J .Glowinski, L .L . I v e r s e n and J .Axelrod, J ,Pharmacol .Exp. 151,385(1966) Therap, 75 L.C .F .Hanson, Psychopharmacologia L O , 289(1967). 76. C o m m i t t e e on Alcoholism and A d d i c t i o n and Council on Mental H e a l t h , J .Am.Med .Assoc 197,1023(1966). 77. P.H.Connel1, J.Am.Med.Assoc.~6,718(1966). 7 8 . H.Leuner, A r z n e i m i t t e l - F o r s c h . 16,253(1966). 79, J J a l i t z , D i s .Nerv.Syst. 2 7 , 4 3 ( m 6 6 ) . 80. C .Savage, J .Fadiman, R .Mogar and M .Hughes, I n t .J .Neurop s y c h i a t 2,241(1966). 81. L.Bender, Dis.Nerv.Syst. 27,39(1966) 82. H.A.Abramson, Am.J .Psychotherapy, 20,415(1966). 83. S .Cohen, Psychosomatics V I I , 1 8 2 ( 1 9 ~ ) . 84. E d i t o r i a l , J.Am,Med.Assoc, 198,190(1966). 85. L.E.Hollister and A . J . F r i e d h o f f , Nature, =,48(1966). 86. A.J.Friedhoff and L . E . H o l l i s t e r , Biochem.Pharmaco1 .15(1966). 8 7 . B . H e l l e r , I n t .J.Neuropsychiat. 2,193(1966). 88. T J - R u n g e , F-Lara, N.Thurman, J.W.Keyes and S . H o e r s t e r , J . Nerv.Ment .Dis, %,470(1966). 89. A.A,Baulton and C .A.Felton, Nature 211,1404(1966), 211,1406 (1 966 ) 90. C ,E , B e l l and A ,R .S ommerville, Nature 91. H .Neubauer, D S u n d l a n d and S .Gershon, J .Nerv.Ment . D i s . L42 265(1966). 92, A.Bauer, A r z n e i m i t t e l - F o r s c h , 16(2a),233(1966). 93. K.A.Fltige1 and R - S t o e r g e r , A r z n e h i t t e l - F o r s c h . lh,235(1966), 94. D .Bente, R - S t o e r g e r and N .A.Tautz, A r z n e i m i t t e l - F o r s c h , 231 (1966)
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95. M.L.Brown, S .Gershon, W.J .Land and B .Korol, A r c h , i n t .Pharmacodyn. 160,407(1966). 96. G .A .Rogeners , L .G .Krugman and L .G .Abood , Biochim. Biophys A c t a E , 3 1 9 ( 1966) 97 2 ,Votava, I .PodValova and M .Vojtechovsky, A r z n e i m i t t e l Forsch. 16(2a),220(1966).
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Chapter 3.
Sedatives, Hypnotics, Anticonvulsants, Muscle Relaxants, General Anesthetics Cornelius K. Cain, McNeil L a b o r a t o r i e s , I n c . , F o r t Washington, Pa. Introduction: During 1966, s e v e r a l new types of c h e m i c a l s t r u c t u r e s w e r e r e p o r t e d to have c e n t r a l nervous s y s t e m d e p r e s s a n t activity, and f u r t h e r studies w e r e d e s c r i b e d of compounds previously c l a s s i f i e d in t h i s a r e a . The p r o b l e m of defining f u r t h e r the type of activity to p r e dict whether a given d e p r e s s a n t w i l l be of clinical application a s a n antipsychotic, anti- anxiety agent, sedative, hypnotic, anti - convul sant o r anesthetic continues to occupy the attention of many investigators. S e v e r a l a p p r o a c h e s to the p r o b l e m have been used. Krnjevic and Videk') d e s c r i b e d a new screening t e s t based on a "natural" r e a c t i o n of a r a t , namely the e n t r a n c e into a darkened cage through a hole of suitable s i z e ( 5 cm. ). E i t h e r of s e v e r a l d e p r e s s a n t s , chlorpromazine, r e s e r p i n e , phenobarbital, etc. i n c r e a s e d the t i m e r e q u i r e d f o r t h i s reaction. A pyschostimulant, amphetamine, d e c r e a s e d t h e t i m e , a s did the a n t i - d e p r e s s a n t s i m i p r a m i n e o r nialamide. The effect of a d m i n i s t r a t i o n of v a r i o u s compounds to a n i m a l s o r m a n on the formation, m e t a b o l i s m and concentration i n o r g a n s o r t i s s u e s of biogenic a m i n e s continues to b e actively p u r s u e d i n many l a b o r a t o r i e s . Of p a r t i c u l a r i n t e r e s t a r e r e c e n t studies on serotonin. Brodie and cow o r k e r s 2 ) suggested that the sedative effects of r e s e r p i n e a r e r e l a t e d to the initial r a t e a t which serotonin i s r e l e a s e d f r o m the brain. Koe p-chlorophenylalanine i s a potent and s e l e c and Weissman3) found that tive depletor of b r a i n serotonin i n m i c e , r a t s and dogs. N o behavioral changes w e r e noted i n r a t s even when the serotonin level w a s reduced to l e s s than ten p e r c e n t of the control value; however, the c h a r a c t e r i s t i c signs elicited by r e s e r p i n e o r tetrabenazine in t h e s e a n i m a l s w e r e not blocked. C r e m a t a and Koe4) r e p o r t e d clinical pharmacological evaluation of p-chlorophenylalanine i n s i x n o r m a l humans. Gradual i n c r e a s e in dosage to 3 grams p e r day r e s u l t e d i n a decline in blood serotonin to 60-7070 of p r e t r e a t m e n t l e v e l s and in u r i n a r y excretion of 5-hydroxy-3indoleacetic a c i d to 10-500J. N o c l e a r - c u t signs of effects on the c e n t r a l nervous s y s t e m w e r e noted. R e f e r e n c e s m a y be found i n the l i t e r a t u r e to the influence of alm o s t e v e r known CNS d e p r e s s a n t on the EEG pattern. Eidelberg, Miller and Long 53 r e p o r t effects of s e v e r a l psychoactive compounds, especially
Chap. 3
D e p r e s sant s
Gain
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those a l t e r i n g biogenic a m i n e l e v e l s , on EEG's in c a t s ; they include many r e f e r e n c e s . T h e r e i s growing i n t e r e s t in the effect of CNS d e p r e s s a n t s , p a r t i c u l a r l y hypnotics, on sleep p a t t e r n s . Excellent introductions to the subject m a y be found i n t h e proceedings of a symposium') and in a review by P i e r i and Hcrlimann. 7, A m o r e r e c e n t symposium on the s a m e subject w a s held in Wurzburg in 1966. P r o c e e d i n g s should b e publ i s h e d shortly. Sedatives and Hypnotics: Additional r e p o r t s 8 , 9, 10, 1 1 , 1 2 9 13) have app e a r e d describing successful clinical u s e of n i t r a z e p a m , MogadonB, RO 4-5360 ( I ) a s a hypnotic i n d o s e s of 5 o r 10 m g . , especially in older patients. However, s o m e "hangover" o c c u r r e d , p a r t i c u l a r l y with the 10 m g , dose.
A r e l a t e d compound, RO 5-6901 (11), w a s studied in 24 patients and found to b e a s effective a hypnotic i n a 15 mg. d o s e a s w a s 100 mg. of secobarbital. 14) The effect of n i t r a z e p a m on s l e e p p a t t e r n s in humans w a s c o m p a r e d with that of phenobarbital and diazepam. 15) Nitrazepam d i f f e r s f r o m the o t h e r d r u g s in the p a t t e r n of alpha and beta waves i n d e e p e r sleep p a t t e r n s ; t h i s m a y b e indicative of paradoxical sleep. Methaqualone (111) w a s r e p o r t e d to be a s effective in a 2 0 0 mg. d o s e a s 100 mg. secobarbital without significant side effects16) and to show no evidence of hepatic dysfunction. 17) A study of the m e t a b o l i s m of methaqualone in humans18' 19) r e sulted i n the isolation f r o m the u r i n e of s i x m e t a b o l i t e s resulting f r o m hydroxylation of the 2-methyl group, the o-tolyl group o r the benz portion ( 111 ) of the nucleus.
26 -
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-
C N S Agents
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Trioxazine ( T r i m e t o z i n e ) ( I V ) w a s d e s c r i b e d a s a n effective dayt i m e sedative") i n a d o s e of 300-1500 mg. p e r day and a s a mild t r a n quilizing drug which gave a f a l s e positive u r i n e glucose t e s t i n two patients using enzyme t e s t p a p e r s . 2 1 ) The g e n e r i c name Roletamide was r e g i s t e r e d f o r C L 59, 112 ( V ) a s a hypnotic; 22) no f u r t h e r published information could b e found.
Sjoqvist and Lasagnaz3) r e p o r t e d that 2 5 o r 50 m g . of doxylamine (DecaprynB) succinate w a s m o r e effective clinically a s a hypnotic than 100 m g . of secobarbital but not a s effective a s 200 mg. of the l a t t e r . They caution that no suitable antidote i s available i n c a s e of over-dosage.
(VI)
In a detailed study of a p y r r o l o pyrimidine, BW 58-271 ( V I ) , Norton and Jewett2*) found that the compound w a s a potent hypnotic agent ( t h r e e t i m e s a s active a s hexobarbital). It a l s o had local anesthetic and hypotensive activity. I t s m o s t unusual effect was sudden suppression of the EEG i n conscious c a t s lasting f o r s e v e r a l minutes a f t e r intravenous injection.
DaVanzo and c o - ~ o r k e r s ~r e~p)o r t e d that a n oxazolidinone derivative, AHR I 2 0 9 ( V I I ) , showed psychosedative activity i n animals.
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T h r e e metabolic p r o d u c t s of methyprylon ( V I I I ) w e r e isolated and identified ten y e a r s ago. 26) BEsche and Schmidt”) r e c e n t l y identified a 3-oxoglutarimide ( I X ) a s a n additional metabolite i s o l a t e d f r o m human urine.
H
( VIII)
C e n t r a l Muscle Relaxants: Chlorophenesin c a r b a m a t e (Maolatem) w a s f i r s t m a r k e t e d in 1966. I t s pharmacology w a s thoroughly d e s c r i b e d by Matthews and c o - w o r k e r s Z 8 ) i n 1963. S e v e r a l clinical studies have been Metabolic studies 3 2 y 33’ 34) showed that in m a n , reported. 291 30’ 31) about 85% of the a d m i n i s t e r e d d o s e w a s e x c r e t e d in the u r i n e a s the 0-glucuronide. S i m i l a r r e s u l t s w e r e obtained i n the r a t . In the dog, the m a j o r metabolite w a s the s a m e compound, but a p p r e c i a b l e amounts p-chlorophenoxylactic of a c i d i c p r o d u c t s resulting f r o m oxidation to p-chlorophenoxyacetic a c i d and p-chlorophenol w e r e a l s o isolated. acid, -
/ \ q
T
-. ._
0
Y N NT -u
H
2
CH3 (X)
Yale and L ~ s e e p~r e~p a) r e d f o r t y s i x 1 , 3, 4-oxadiazoles and oxadia z o l i n e s and found many of them to be m o d e r a t e l y a c t i v e m u s c l e r e laxants. The m o s t potent of the s e r i e s w a s the compound of s t r u c ture ( X ) .
Brittai~~ r e~p o~r )t e d that a t r i a z i n e derivative, CB 2487 ( X I ) , r e s e m b l e d mephenesin pharmacologically, both qualitatively and quantitatively.
CH3 A compound of unusual s t r u c t u r e ( X U ) , a s i l a c a r b a m a t e , w a s p r e p a r e d by F e s s e n d e n and Coon37) and found to show m u s c l e r e laxant activity of brief duration.
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Anti-convulsants: Screening f o r t h i s type of pharmacological action continues, and a c t i v e compounds a r e found although none a p p e a r to be promising enough to w a r r a n t f u r t h e r investigation. Swinyard and C a ~ t e l l i o n ~studied ~) the anti-convulsant p r o p e r t i e s of a s e r i e s of benzodiazepines and suggested that a compound offering a p p r e c i a b l e advantages o v e r those c u r r e n t l y i n u s e a s anti-epileptics might be found i n t h i s a r e a . Mishie, Weary and B e r g e r 3 9 ) r e p o r t e d that a s e r i e s of chemically r e l a t e d t h i o s e m i c a r b a z i d e , thiourea o r u r e a d e r i v a t i v e s m a y be divided into groups of convulsants, anti-convulsants and those of mixed action. Anesthetics: Two excellent r e v i e w s have recently appeared. Dobkin and S u 4 U ) s c u s s e d all types of new g e n e r a l a n e s t h e t i c s (including e l e c t r i c a l ) f r o m the viewpoint of clinical utility. The v a r i o u s agents w e r e c o m p a r e d with r e s p e c t to induction, e m e r g e n c e , hypnosis, a n a l g e s i a , etc., and side effects w e r e listed. D e s i r a b l e p r o p e r t i e s of a n improved anesthetic w e r e included. Dundee41) reviewed inhalants, b a r b i t u r a t e s and propanidid f r o m the viewpoint of clinical pharmacology. (a) Inhalants: A s u m m a r y of the National Halothane Study (Bunker Committee Report) w a s published. 42) Data f r o m m o r e than 8 5 0 , 0 0 0 anesthetic a d m i n i s t r a t i o n s w e r e compiled and studied. Halothane deaths amounted to 1. 87% compared to 1. 9370 f o r all anesthetic p r a c t i c e s . The possibility could not be excluded that t h e r e m a y be a halothane-related hepatic n e c r o s i s , but i f so, i t o c c u r s v e r y r a r e l y . The study d e m o n s t r a t e d that the o v e r a l l d e a t h - r a t e p r o b l e m i s much g r e a t e r in i t s implications f o r patient c a r e than the p r o b l e m of m a s s i v e hepatic n e c r o s i s . (b) Injection Anesthetics: C o r s s e n a n d Domino43) supplemented t h e i r p r e v i o u s study of CI 581 ( XIII), a n analog of phencyclidine (SernylB) ( X I V ) , with a r e p o r t of 139 clinical c a s e s i n which adequate a n e s t h e s i a c1\
( XIII)
w a s obtained in 9270. E m e r g e n c e w a s occasionally a s s o c i a t e d with a psychotomimetic r e s p o n s e which w a s controlled by small d o s e s of a barbiturate.
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I n t e r e s t i n y-hydroxybutyric a c i d ( o r i t s sodium s a l t o r the lactone) a s a n intravenous anesthetic*') continues. T h e r e a p p e a r s to be s o m e question whether the compound h a s sedative and hypnotic p r o p e r t i e s i n low doses. Metcalf, Emde and Stripe44) studied EEG and beh a v i o r a l p r o p e r t i e s of the compound i n humans and r e p o r t e d that t h e r e w a s a sudden shift f r o m responsivity to unconsciousness. On the b a s i s of t h e EEG r e c o r d s , they speculate that the drug d e p r e s s e s r e t i c u l a r c e n t e r s which o r d i n a r i l y inhibit the onset of slow sleep. G e s s a and c o - ~ o r k e r s ~r e~p o ) r t e d that i n t r a p e r i t o n e a l a d m i n i s t r a t i o n of y-hydroxybutyric a c i d t o r a t s and r a b b i t s p r o d u c e s m a r k e d and r a p i d i n c r e a s e i n b r a i n dopamine which w a s not due to monoamine oxidase inhibition o r to stimulation of dopamine synthesis. No a p p r e c i a b l e change in b r a i n norepinephrine o r serotonin o c c u r r e d . The l o s s of righting r e f l e x which w a s o b s e r v e d c o r r e l a t e d t e m p o r a l l y with high dopamine l e v e l s i n the brain. Sprince, J o s e p h s and Wilpizeski4') m e a s u r e d the effects of y-hydroxybutyric a c i d and s e v e r a l r e l a t e d compounds by noting l o s s of righting r e f l e x a f t e r i n t r a p e r i t o n e a l injection i n r a t s . y-Butyrolactone w a s a c t i v e m o r e quickly and f o r a longer t i m e than equivalent amounts of the acid. 1, 4-Butanediol w a s c o m p a r a b l e in activity to the acid, but 1, 3-butanediol w a s much l e s s active. P y r u v a t e prevented o r r e v e r s e d the LRR effect of the acid, the lactone and the 1, 4-diol.
S e v e r a l a r t i c l e s indicate that t h e r e i s continuing i n t e r e s t i n propanidid ( X V ) a s a n u l t r a - s h o r t anesthetic B ~ u r e a u ~ and ~ )Dumoulin e t al. 48)
CH,COOC 3 ~ 7
r e p o r t e d favorable r e s u l t s in m i n o r p r o c e d u r e s i n ambulatory patients, a s a n induction,anesthetic and in convulsive therapy. Swerdlow49) cons i d e r e d i t worthy of f u r t h e r investigation i n dental a n e s t h e s i a . C l a r k e and Dundee") included t h e i r cons i d e r a b l e number of publications on propanidid a n e s t h e s i a i n a s u r v e y of experimental and clinical p h a r m a cology of the compound.
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Adjuncts to Anesthesia (a) ------R e s p i r a t o r y Stimulants: Doxapram ( X V I ) a p p e a r s to offer advantages o v e r o t h e r analeptics f o r t h i s action, but i t does not a p p e a r to be widely u s e d clinically. K1emm513 52) found that i t i n c r e a s e d r e s p i r a t o r y minute volume a s much a s 20070 i n one minute in dogs deeply anesthetized with sodium pentothal, a n effect much g r e a t e r than that using the b e s t combination a n a l e p t i c s r e p o r t e d by o t h e r s .
--------
I ‘ZH5
Funderburk, Oliver and Ward53) r e p o r t e d that intravenous a d m i n i s t r a tion of doxapram to c a t s a n d dogs c a u s e d selective stimulation of the r e s p i r a t o r y c e n t e r s i n the medulla i n low d o s e s (0.2-1.0 mg. / k g . ) , stimulation of the c o r d i n higher d o s e s ( 3 mg. / k g . ) and stimulation of higher c e n t e r s i n the b r a i n i n still l a r g e r d o s e s .
----
(b) --------Neuroleptanal_gesics: Brief r e v i e w s of this topic m a y be found i n r e f e r e n c e 40 a n d i n a chapter by C o r s s e n . 54) M o r e information i s contained i n two symposia on the subject which have been recently published one held i n Edinburgh i n 196455) and another i n Zurich i n 1965. 5 b )
By far the m o s t widely u s e d p r e p a r a t i o n of t h i s type i s Innovar@, a combination of the neuroleptic, droperidol, a n d the a n a l g e s i c , fentanyl. Some 30 a r t i c l e s a p p e a r e d during 1966 describing its u s e i n humans with o r without n i t r o u s oxide. Innovar@ Vet continues to find wide application f o r s u r g i c a l p r o c e d u r e s i n dogs. A r e c e n t a r t i c l e 5 7 ) indicates equally good r e s u l t s in primates.
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References 1. H. Krnjevic and M. Videk, Psychopharmacologia, 10, 308 (1967). 2. B. B. Brodie, M. S. C o m e r , E. Costa and A. Dlabac, J . P h a r m a c o l . Exp. T h e r a p . , 152, 340 (1966). 3. B. K. Koe and A. Weissman, i b i d . , 154, 499 (1966). 4. V. Y . C r e m a t a , J r . a n d B . K. Koe, Clin. P h a r m a c o l . T h e r a p . , 7, 768 (1966). 5. E. Eidelberg, M. K. M i l l e r and M. Long, Int. J . N e u r o p h a r m a c o l . , -5, 59 (1966). 6. K. A k e r t , C. Bally and J . P. Schade, E d s . , "Sleep Mechanisms", P r o g r e s s i n B r a i n R e s e a r c h , Vol. 18, E l s e v i e r Publ. C o . , New York, N. Y . , 1965. 15, 1126 (1965). 7. L. P i e r i and A. d h r l i m a n n , A r z n e i m i t t e l - F o r s c h . , 8. W . H. LeRiche, A. C s i m a and M. Dobson, Can. Med. A s s o c . J . , 95, 300 (1966). 196, 829 (1966). 9. A . G. F r a s e r and F. G. G. Shepherd, P r a c t i c i o n e r , 10. H. E g e r t and 0. Jahn, A r z n e i m i t t e l - F o r s c h . , 15, 1159 (1965). 11. W. F. Borck, ibid., 1155 (1965). 12. G. H a r r e r , i b i d . , 15, 1152 (1965). 13. J. M. Muller and B T D e n i s , Semaine d e Hop. Paris, 42, 117 (1966). 14. H. J i c k , D. Slone, B. Dinan and H. Muench, New EngT J. Med., 275, 1399 (1966). 15. F. Cornu, Schweiz. Arch. Neurol. Neurochir. P s y c h i a t . ,%, 164 (1965). 16. S. Cohen, W e s t e r n Med., 6, 266 (1965). 17. I. H. B r e s l o w and S. Z . Haidri, Clin. P h a r m a c o l . T h e r a p . , 7, 359 (1966). 18. F. R . P r e u s z , H. M. H a s s l e r and R . Kb(pf, A r z n e i m i t t e l - F o r s c h . , 16, 395 (1966). 19. H. Nowak, G. S c h o r r e and R . S t r u l l e r , ibid., 16, 407 (1966). 20. M. S e r c l , J . Kovarik, 0. J a r o s , V. Otakar a n F D . Simkova, P s y c h o pharm. Abstracts, 6, 163 (1966). 21. J . L. Claghorn, J. Kinross-Wright and W. M. Mc I s a a c , J. New Drugs, 153 (1966). 22. Anon., J. A m . Med. A s s o c . , 199, 116 (1-23-67). 23. F. Sjoqvist and L. Lasagna, Clin. P h a r m a c o l . T h e r a p . , 8, 48 (1967). 24. S. Norton a n d R . E. Jewett, J. P h a r m a c o l . Exp. T h e r a p . , 154, 152 (1966). 25. J. P. Da Vanzo, W. H. F u n d e r b u r k , B. V. F r a n k o and J . W. Ward, P h a r m a c o l o g i s t , 8, 223 (1966). 26. K. Bernhard,-M. J u s t , A. H. Lutz and J. P. Vuilleumier, Helv. Chim. A z t a , 40, 436 (1957). 27. J. B o s c h e a n d Georg Schmidt, A r z n e i m i t t e l - F o r s c h . , 16, 548 (1966). 28. R . J. Matthews, J. P. Davanzo, R . J. Collins and M . J . V a n d e r B r o o k , Arch. Intern. P h a r m a c o d y n . , 143, 574 (1963). 29. F. H. Stern, Am. J. T r o p . Med. Hyg., 12, 832 (1963).
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30. F. H. Stern, Clin. Med., 70, 1451 (1963). 31. W. A. Abruzzi, ibid., 7 1 , 3 2 9 (1964). 32. D. R . Buhler, J. P h a r m a c o l . Exp. T h e r a p . , 145, 232 (1964). 33. D. R . Buhler, Biochem. P h a r m a c o l . , 14, 371 (1965). 34. D. R . Buhler, H. Harpootlian and R. L T J o h n s t o n , i b i d . , 15, 1507 (1966). 35. H. L. Y a l e and K. L o s e e , J. Med. C h e m . , 9, 478 (1966). 36. R . T. B r i t t a i n , J. P h a r m . P h a r m a c o l . , 18,-294 (1966). 37. R . J . F e s s e n d e n and M. D. Coon, J. M e d T C h e m . , 9, 262 (1966). 38. E. A. Swinyard and A. W. Castellion, J. P h a r m a c o c Exp. T h e r a p . , 151, 369 (1966). 153, 387 (1966). 39. K. Nishie, M. Weary and A . B e r g e r , ibid., 7, 648 40. A . B. D o b k i n a n d J . P - G . Su, Clin. P h a r m a c o l . T h e r a p . , ( 1966). 41. J . W. Dundee, ibid., 8, 91 (1967). 42. Anon., J. Am. Med. ASSOC., 197, 775 (1966). 43. G. C o r s s e n and E. F. Domino, Anesthesia Analgesia, C u r r e n t R e s . , 45, 29 (1966). 44. D. R . Metcalf, R. N. E m d e a n d J. T. Stripe, Electroencephalog. Clin. Neurophysiol., 20, 506 (1966). 45. G. L. G e s s a , L r V a r q u i , F. Crabai, G. C. B o e r o , F. Caboni and R . Camba, Life S c i . , 5, 1921 (1966). 5, 46. H. Sprince, J . A . J o s e p h s , J r . and C. R . Wilpizeski, ibid., 2041 (1966). 47. J . Boureau, Anesthesie Analgesie, Reanimation, 23, 573 (1966). 23, 565 48. E. Dumoulin, L. L e c r o n , D. Levy and M. Otto, ibid., ( 1966). 49. M. Swerdlow, B r i t . J . Anesth., 37, 785 (1965). 50. R . S. J . C l a r k e and J . W. D u n d e c Anesthesia Analgesia, C u r r e n t R e s . , 45, 250 (1966). R .. Klemm, J. Am. Vet. Med. A S S O C . ,148, 8 9 4 (1966). 51. W 52. W. R . Klemm, Toxicol. Appl. P h a r m a c o l . , 8, 505 (1966). 53. W . H. Funderburk, K. L. Oliver and J . W. Ward, J. P h a r m a c o l . Exp. Therap., 151, 360 (1966). 54. G. C o r s s e n i n " P r i n c i p l e s of Anesthesiology", V. J . Collins, Ed. , L e a and F e b i g e r , Philadelphia, 1966, pp. 428-434. 55. N. W. Shephard, Ed., "The Application of Neuroleptanalgesia", P e r g a m o n P r e s s , New York, 1966. 56. M. G e m p e r l e , Ed. , " F o r t s c h r i t t e d e r Neuroleptanalgesie", SpringerVerlag, B e r l i n , Heidelberg, New York, 1966. 57. W. E. Field, J . Yelnosky, J. Mundy, J. Mitchell, J. A m . Vet. Med. ASSOC., 149, 896 (1966).
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C h a p t e r 4 . A n a l g e t i c s --- S t r o n g and Weak Louis S H a r r i s and W i l l i a m L. Dewey U n i v e r s i t y of North C a r o l i n a , Chapel H i l l , N.C.
.
I . I n t r o d u c t i o n - The p a s t y e a r i n the f i e l d of a n a l g e s i c s must be c o n s i d e r e d one of c o n s o l i d a t i o n and e x p a n s i o n . There w e r e no s t a r t l i n g b r e a k t h r o u g h s i n o u r u n d e r s t a n d i n g of a n a l g e s i c s n o r w e r e any markedly d i f f e r e n t new classes of a n a l g e s i c s d i s covered .)
11. S t r o w A n a l g e s i c s A. Morphines and Morphinans - Abdul-Rahman and h i s c o l l e a g u e s 1 d e s c r i b e d a new s y n t h e s i s of 6-methylenedihydrodeoxymorphine I . T h i s compound w a s found t o b e somewhat more p o t e n t t h a n morphine b u t had e s s e n t i a l l y t h e same p h a r m a c o l o g i c a l properties. I n man t h e compound i s s a i d t o have anal e s i c , s e d a t i v e and r e s p i r a t o r y d e p r e s s a n t a c t i o n s . Bucketts reported on the pharmacolbgy of i4-c?nnamoyloxycodeinone I1 t h e most The compound p o t e n t series of esters of 14-hydroxycodeinone.
fl-Me
proved t o b e about 100 t i m e s more a c t i v e t h a n morphine as a n a n a l g e s i c w i t h a b e t t e r t h e r a p e u t i c r a t i o p a r t i c u l a r l y by t h e o r a l and subcutaneous r o u t e s . I n o t h e r pharmacological parameters I1 w a s q u a l i t a t i v e l y q u i t e s i m i l a r t o morphine. Gates and K l e i n 3 have p r e p a r s d some metamorphinan d e r i v a t i v e s (111) where t h e e t h a n h i n e b r i d g e t e r m i n a t e s a t C14 r a t h e r than C 1 3 . The N-methyl d e r i v a t i v e w a s t e s t e d as a n a n a l g e s i c and t h e N-cyclopropylmethyl compound as a n a n a l g e s i c
HO
&
I11
RO
&e- z:6~ R
1
IV
a n t a g o n i s t , Both compounds w e r e e s s e n t i a l l y i n a c t i v e , l e n d i n g c o n f i r m a t i o n t o the h y p o t h e s i s of Braenden, Eddy and Halbachb t h a t a phenyl group o r g r o u p i s o s t e r i c w i t h phenyl c o n n e c t e d d i r e c t l y t o a q u a r t e r n a r y carbon i s a necessary s t r u c t u r a l feature of a l l s t r o n g a n a l g e s i c s .
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B. OriPayine Analogs Bentley and h i s colleagues5,6 have continued t h e n v e r y i n t e r e s t i n g work i n t h e 6,14-endoethenot e t r a h y d r o t h e b a i n e series of a n a l g e s i c s of t h e g e n e r a l s t r u c t u r e I V , They have n o t e d , i n g e n e r a l , t h a t i f one keeps R and R" c o n s t a n t , i n c r e a s i n g R ' from H through C H 3 and C2H5 t o C3H7 l e a d s t o a p r o g r e s s i v e i n c r e a s e i n a n a l g e s i c a c t i v i t y . The N - s u b s t i t u e n t s u s u a l l y a s s o c i a t e d w i t h n a r c o t i c antagonism ( a l l y l , cyclopropylmethyl) g i v e a n t a g o n i s t s only when R ' i s H, C H 3 or C2H5. The most p o t e n t analgesics and a n t a g o n i s t s are found i n t h e p h e n o l i c series (R=H). Reduction of t h e 6,14etheno b r i d g e produced o n l y s l i g h t changes i n either a n a l g e s i c o r a n t a g o n i s t i c a c t i v i t y . A r e v e r s a l of t h e s t e r e o c h e m i s t r y a t C-19, a l t h o u g h not e x t e n s i v e l y explored, r e v e a l e d t h a t varying t h e a l k y l group R' now no l o n g e r e f f e c t e d a n a l g e s i c a c t i v i t y , T h i s i n d i c a t e d that t h e a l c o h o l i c group a t C-7 might be a s t r o n g f a c t o r i n attachment a t t h e r e c e p t o r s u r f a c e , T h e marked d e c r e a s e i n a n a l g e s i c a c t i v i t y noted w i t h dehydrat i o n of t h i s a l c o h o l l e n d s credence t o t h i s h y p o t h e s i s , On t h e basis of these and o t h e r s t u d i e s Bentley and h i s c o l l e a g u e s 5 r 6 have proposed a h y p o t h e t i c a l r e c e p t o r s i t e (V) which w i l l accommodate these new molecules as w e l l as t h e o l d e r analgesic s t r u c t u r e s , -Gt
VI I 1-
- -- - --
-Recept_o?L - -- - - _- J
- May and Eddy7 have r e p o r t e d the r e s o l u t i o n of c i s - 5 , 9 - d i e t ~ y l - 2 ~ - h y d r o x y - 2 - m e t h y l - 6 , 7 - b e ~ o m o r ~ h a n (VI). T h x - ) - i s o m e r i s as a c t i v e as morphine and about twice as p o t e n t as the racemate i n t h e mouse h o t - p l a t e t e s t . The (+)-isomer a l s o had a n a l g e s i c a c t i v i t y , being 1/6 as p o t e n t as i t s antipode. S u r p r i s i n g l y , t h e (-)-isomer w a s .found t o prec i p i t a t e w i t h d r a w a l i n addicted monkeys8 and t o have a mixture of a n a l g e s i c and a n a l g e s i c - a n t a g o n i s t p r o p e r t i e s i n the mouse t a i l - f l i c k t e s t g , The (+.)-isomer w a s found t o have a d e f i n i t e physical. dependence c a p a c i t y i n monkeys while t h e racemate w a s e s s e n t i a l l y i n a c t i v e i n t h i s r e g a r d , This i s t h e f i r s t f i n d ing of a n t a g o n i s t i c a c t i v i t y b a N - m e t h y l d e r i v a t i v e and would suggest t h a t t h e low p h y s i c a l dependence c a p a c i t y of t h e racemate might be due t o some form of antagonism between t h e two a n t i p o d e s . A similar case has a l s o been r e p o r t e d by C l a r k e and h i s They have prepared a series of 5-phenyl subco-workerslO,ll, s t i t u t e d benzomorphans, I n t h e case i l l u s t r a t e d , t h e r e i s good evidence t o i n d i c a t e t h a t t h e r i n g c l o s u r e goes t r a n s . T h i s i s q u i t e d i f f e r e n t from o t h e r similar r i n g c l o s u r e s I n t h i s series where t h e predominent product i s t h e cis-isomerl2, C , Benzamorphans
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I n any case, t h e 5-phenyl compound V I I appears much l i k e a s t r a i g h t f o r w a r d a n a l g e s i c i n t h e l a b o r a t o r y 10. D e s p i t e t h i s , t h e racemate has a low p h y s i c a l dependence c a p a c i t y i n monkeys and the ( - isomer has t h e p r o p e r t i e s of a n a l o r p h i n e - l i k e a n t a g o n i s t l 3 . Again, t h e (+)-isomer has a h i g h p h y s i c a l dependence c a p a c i t y , I n a primary monkey a d d i c t i o n s t u d y (-)-VII produced only a v e r y l o w g r a d e p h y s i c a l dependence, This might be due t o the low s o l u b i l i t y (propylene g l y c o l w a s n e c e s s a r y ) , a b s o r p t i o n , and i r r i t a t i o n a s s o c i a t e d w i t h the drug. The anomalous behavior among t h e isomers i n t h i s and t h e 5 , g - d i e t h y l series may h e l p e x p l a i n t h e a b e r r a n t r e s u l t s c o n s i s t e n t l y obt a i n e d w i t h t h e benzormorphans i n monkey dependence s t u d i e s , K e a t s l 4 has e v a l u a t e d ( - ) - V I I i n man for a n a l g e s i c a c t i v i t y and found i t t o be approximately t w i c e as p o t e n t as morphine, There w a s concomitant r e s p i r a t o r y d e p r e s s i o n which w a s w e l l antagonized by n a l o r p h i n e . I n a d d i c t i o n s t u d i e s i n man, MartinL5 has found t h a t t h e compound produced m i o s i s , w a s i d e n t i f i e d as "dope", and " l i k e d " by p o s t - a d d i c t s . It w a s a l s o p a r t i a l l y a b l e t o s u b s t i t u t e f o r morphine i n dependent subjects. C l a r k e and h i s co-workers have a l s o prepared a number of carbamates i n t h e 5-phenyl seriesl6. One of t h e s e , 2-carboxamide-2'-hydroxy-5-phenyl-6,7-benzMorphan, had weak a n a l g e s i c a c t i v i t y i n t h e h o t - p l a t e t e s t and d i d n o t s u b s t i t u t e for morphine i n t h e addicted monkeyl3, T h i s compound has been r e ported t o have c o d e i n e - l i k e a n a l g e s i c a c t i v i t y i n manl7. D , P i p e r i d i n e and Diphenylmethane Analogs - S a s a k i and h i s colleaguesL8 d i s c u s s i n g t h e a b s o l u t e c o n f i g u r a t i o n and c o n f o r mation-of sane l12-dipKenylethylamine d e r i G a t i v e s r e p o r t e d t h a t t h e a n a l g e s i c a c t i v i t y of (-)-N,N-dimethyl-1,2-diphenylethylamine was c o n s i s t e n t w i t h i t s s t e r e o c h e m i c a l resemblance t o (-)-morphine, Nuclear magnetic resonance d a t a f o r t h i s compound i n d i c a t e d a n e c l i p s e d conformation t o t h e extent of 22%. I t w a s p o s t u l a t e d t h a t t h i s might be expected t o f a v o r i t s approach t o some r e a c t i v e s u r f a c e i n t h e nervous system. Casey and Hassanlg have prepared ( R S ) - , (RI-, and (S)-N-(2dimethylaminopropyl) p r o p i o a n i l i d e ( V I I I A) and t h e benzylmethylamino analogs of methadone and isornethadone and r e p o r t e d pharmacological d a t a f o r the v a r i o u s enantiomorphs of diampromid ( V I I I B) and t h e N,N-dimethyl d e r i v a t i v e V I I I C .
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go-6
-Me
A: R=@, R'=OCOEt B: R=OCOEt, R'=@
R
I Me
X
The (S)-enantiomorphs of t h e a n i l i d e s w e r e more a c t i v e than t h e (RS)- or (R)- forms and t h e a r y l a l k y l compounds were c o n s i d e r a b l y more a c t i v e t h a n t h e d i a l k y l compound. N-Benzylmethadone and N-benzylisomethadone had l i t t l e a c t i v i t y , These r e s u l t s would i n d i c a t e t h a t t h e b a s i c -anLlide a n a l g e s i c s have a d i f f e r e n t mode of binding t o t h e r e c e p t o r t h a n do t h e 3amino-1 1-diphenylpropyl compounds .
,
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E. Miscellaneous Smissman and Steinman20 r e p o r t e d t h e s y n t h e s i s of t h e two isomeric f o m s of 1-methyl-4-phenyltrans-decahydro-4-propionoxy q u i n o l i n e ( I X A and B ) . This r i g i d r i n g system v a r i e s o n l y i n t h e conformation of t h e a r o m a t i c r i n g and it w a s hoped t h a t t h e b i o l o g i c a l a c t i v i t y of t h e s e compounds wouLd r e s o l v e t h e c o n t r o v e r s y o v e r whether a n axial aromatic f u n c t i o n w a s n e c e s s a r y f o r a n a l g e s i c a c t i v i t y , The two compounds d i f f e r e d n e i t h e r i n t h e i r a c u t e t o x i c i t y nor t h e i r a n a l g e s i c ED50. Thus, i t would appear t h a t no d e f i n i t e conformational requirement of t h e phenyl group i s necessary f o r analgesic a c t i v i t y . The pharmacologic p r o p e r t i e s of t h e p r o d i l i d i n e analog X w a s r e p o r t e d 2 1 , X w a s a c o n s i d e r a b l y more a c t i v e a n a l g e s i c t h a n p r o d i l i d i n e and i t s a n t i n o c i c e p t i v e a c t i o n w a s a n t a gonized by nalorphine. The &-isomer w a s twice as p o t e n t as t h e &-isomer A c o n s i d e r a b l e i n t e r e s t w a s shown Last y e a r i n a s t e r o i d which w a s r e p o r i g d o have s t r o n g ana$$esic p r o p e r t i e s i n both from t h e same l a b o r a animals and man 7 25. A r e c e n t paper t o r i e s has r e t r a c t e d t h e s e r e s u l t s . Methotrimeprazine, a p h e n o t h i a z i n e w i t h s t r o n g a n a l g e s i c particularly a c t i v i t y , has r e c e i v e d F . D . A . approval. sum up t h e e x p e r i c a r e f u l s t u d y by Houde and h i s c o l l e a g u e s ence w i t h t h i s d r u g , They f i n d methotrimeprazine, u n l i k e chlorpromazine, t o be a n e f f e c t i v e a n a l g e s i c . I t i s about o n e h a l f as p o t e n t as morphine and i s a s s o c i a t e d w i t h a high i n c i dence of s e d a t i o n and o r t h o s t a t i c hypotension. The drug, howe v e r , produced l i t t l e nausea, r e s p i r a t o r y d e p r e s s i o n , and has no morphine-like a d d i c t i o n p o t e n t i a l . I t r e p r e s e n t s a class of a n a l g e s i c s which d i f f e r s q u a l i t a t i v e l y q u i t e markedly from morphine.
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F , Biochemical and Pharmacological C o n s i d e r a t i o n s - A number of p a p e r s have been p u b l i s h e d i n a n e f f o r t t o shed more l i g h t on the mechanism of s t r o n g a n a l g e s i c s a t t h e molecul a r l e v e l , Casy and Wright measured t h e i o n i z a t i o n constants and p a r t i t i o n c o e f f i c i e n t s of a number of 2-benzylbenzimidaz o l e s . N o good c o r r e l a t i o n w a s found between e i t h e r of t h e s e p a r a m e t e r s and a n a l g e s i c a c t i v i t y . The i n t r a c e l l u l a r d i s t r i b u t i o n of dihydromorphine t h e b r a i n and l i v e r of r a t s w a s s t u d i e d by Praag and .Simoniy. They found most of t h e d r u g i n t h e s o l u b l e f r a c t i o n . A s i m i l a r s t u d y by Mulez8 g a v e much t h e same r e s u l t s . D e s p i t e a c a r e f u l a n a l y s i s of most s u b c e l l u l a r p a r t i c l e s no s p e c i f i c morphine b i n d i n g s i t e s w e r e found i n either naive o r t o l e r a n t animals nor d i d nalorphine effect tissue l e v e l s o r intracellular d i s t r i b u t i o n .
tQ8
I t has been r e p o r t e d 2 ' t h a t morphine lowers t h e r a t e of i n c o r p o r a t i o n of g l u c o s e i n t o a-aminobutyrate and a s p a t a t e by rat b r a i n vivo. I n g u i n e a p i g c e r e b r a l c o r t e x slices3' h i g h c o n c e n t r a t i o n s of morphine and n a l o r p h i n e s t i m u l a t e d t h e i n c o r p o r a t i o n of P 32 and CL4-labeled p r e c u r s o r s i n t o c e r t a i n phospholipids. The i n c o r p o r a t i o n i n t o p h o s p h a t i d y l c h o l i n e , I t i s p o s t u l a t e d t h a t morphine and however, w a s i n h i b i t e d , n a l o r p h i n e may a c t by s t i m u l a t i n g b i o s y n t h e t i c pathways l e a d i n g t o t i s s u e d e p l e t i o n of D - l T 2 - d i g l y c e r i d e , a n e s s e n t i a l i n t e r m e d i a t e i n t h e b i o s y n t h e s i s of g l y c e r o p h o s p h a t i d e s . Of g r e a t i n t e r e s t i s t h e r e p o r t by Kakunga & &.31 who found t h a t t h e i n t r a c t s t e r n a l i n j e c t i o n of C a + + s u p p r e s s e d t h e a n a l g e s i c e f f e c t s of morphine and o t h e r n a r c o t i c s , EDTA and o t h e r d e c a l c i f y i n g a g e n t s enhanced t h e a c t i o n of the s t r o n a n a l g e s i c s and c o u n t e r a c t e d t h e a n t a g o n i s t i c e f f e c t s of C a$+ These r e s u l t s i n d i c a t e t h a t C a + + i n the C ,N.S. might b e i n volved i n t h e mechanisms by which o p i a t e s exert t h e i r analgesic effects.
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The a t t e m p t s t o r e l a t e n a r c o t i c t o l e r a n c e or a c t i o n t o p r o t e i n or n u c l e i c a c i d s y n t h e s i s h a v e c o n t i n u e d 3 2 ~ 3 3 , 3 4 . To d a t e , no s a t i s f a c t o r y g e n e r a l t h e o r y h a s emerged from t h i s work I t w a s r e p 0 r t e d 3 ~t h a t morphine d o e s n o t a c t as a symp a t h o l y t i c on the i s o l a t e d h e a r t nor does i t a l t e r c a t e c h o l amhe l e v e l s or t h e r e s p o n s e of t h e heart t o sympathomimet m i n e s , On the o t h e r hand, i n v i v o experiments i n the dog $8 r e v e a l t h a t morphine i n c r e a s e d c o n t r a c t i l e f o r c e , T h i s caref u l s t u d y r e v e a l e d t h a t t h e improved v e n t r i c u l a r performance induced by morphine i s i n d i r e c t and p r o b a b l y t h e r e s u l t of s ympathoadrenal d i s c h a r g e
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The e f f e c t of v a r i o u s n a r c o t i c a n a l g e s i c s on t h y r o i d f u n c t i o n have been a s s e s s e d and i t w a s concluded t h a t t h e y d i d not e x e r t a d i r e c t a c t i o n on t h e t h y r o i d but depressed t h y r o i d f u n c t i o n through a n effect on t h e h y p o t h a l a m i c - p i t u i t a r y axis7. This w f u r t h e r c l a r i f i e d i n a n e l e g a n t s t u d y by Lomax and George” whose r e s u l t s l e a d them t o p o s t u l a t e t h a t morphine acts on t h e t h y r o i d by a c t i v a t i n g areas i n t h e p o s t e r i o r hypothalamus which i n h i b i t t h e release of TSH from t h e p i t u i t a r y , 111. Analgesic Antagonists - I n t e r e s t i n t h i s area, p a r t i c u l a r l y from a c l i n i c a l viewpoint, remains very high. Compounds of t h i s class show g r e a t promise as nonaddicting a n a l g e s i c s and a t l e a s t one of them appears t o be q u i t e e f f e c t i v e i n t h e treatment of a d d i c t s . A , Pentazocine - The c l i n i c a l r e p o r t s on t h e u s e of t h i s drug c o n t i n u e t o l o o k f a v o r a b l e . Pentazocine has been compared p a r e n t e r a l l y i n c o n t r o l l e d s t u d i e s w i t h phenazoc’ne i n In p o s t - o p e r a t i v e pain39, and morphine i n cancer p a t i e n t s6 0 b o t h c a s e s t h e drug gave good a n a l g e s i a w i t h a r e l a t i v e l y low s i d e e f f e c t incidence i n t h e post-operative p a t i e n t s . I n t h e c a n c e r p a t i e n t s , who had a h i g h l e v e l of p r i o r n a r c o t i c u s e , a number of f r a n k withdrawal episodes w e r e observed, I t i s obvious t h a t pentazocine w i l l have t o be used c a r e f u l l y i n p a t i e n t s who have been r e c e i v i n g h i g h doses of n a r c o t i c s over a p e r i o d of t h e . T h e e f f e c t of pentazocine on t e r i n e conThe drug t r a c t i l i t y and f e t a l heart r a t e w a s a l s o studiedg1. produced a n o v e r a l l i n c r e a s e i n u t e r i n e a c t i v i t y and d i d not r e t a r d l a b o r , There w e r e no s i g n i f i c a n t changes i n f e t a l heart r a t e . Pentazocine w a s s t a t e d t o be a n e f f e c t i v e analgesic i n l a b o r w i t h a r a p i d onset and s h o r t d u r a t i o n .
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I n a c o n t r o l l e d p o s t - s u r g i c a l analgesic s t ~ d oyr a l~ ~ pentazocine w a s compared t o codeine, a s p i r i n , and a placebo, Pentazocine 50 mg w a s as e f f e c t i v e as codeine 60 m g and more e f f e c t i v e than 600 mg of a s p i r i n . Pentazocine 35 mg w a s more e f f e c t i v e than t h e placebo b u t less e f f e c t i v e t h a n t h e a s p i r i n . It w a s found t h a t the a n a l g e s i c potency of t h e placebo w a s q u i t e h i g h and, as a second dose, w a s functiona1l.y dependent on t h e previous medication , B . Cyclazocine - Cyclazocine i s a p o t e n t n a r c o t i c a n t a g o n i s t which i s a l s o a p o t e n t a n a l g e s i c i n man a s s o c i a t e d w i t h a h i g h i n c i d e n c e of b i z a r r e psychic e f f e c t s . Analgesic doses of c y c l a z o c i n e had l i t t l e e f f e c t on blood p r e s s u r and h e a r t Marked r a t e i n normal v o l u n t e e r s b e f o r e o r a f t e r t i l t i n gG3 CNS e f f e c t s , however, w e r e s e e n , On the b a s i s of i t s behavior i n a d d i c t i o n s t u d i e s , c y c l a z o c i n e as thought t o be of u s e i n trials t h e t r e a t m e n t of n a r c o t i c addicts4x. The ex@ysive i n i t i a t e d L a s t y e a r c o n t i n u e t o be promising Indeed, cont i n u e d r e s e a r c h i n t h i s area w a s s t r o n g l y recommended by a n e x p e r t committee on dependence-producing drugs a t t h e 21st s e s s i o n of t h e United Nations Commission on N a r c o t i c Drugs.
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C . Naloxone - Naloxone, N-allylnoroxymorphone, has engendered a c o n s i d e r a b l e amount of i n t e r e s t . Pharmacological s t u d i e s would i n d i c a t e t h a t t h i s compound r e p r e s e n t s t h e most n e a r l y pure a n t a g o n i s t of t h e compounds y e t t e s t e d , It i s p r a c t i c a l l y devoid of a n a l g e s i c a c t i v i t y i n T ~ The ~ , compound o n l y r a r e l y produces p s y c h o t o m h e t i c e f f e c t s and unl i k e n a l o r p h i n e and c y c l a z o c i n e shows few withdrawal s i g n s a f t e r a b r u p t c e s s a t i o n of c h r o n i c m e d i c a t i o n l 5 , The a b i l i t y of naloxone t o r e l i e v e p a i n i n man i s s t i l l i n doubt14. D , Miscellaneous - The problem of d e v i s i n g a l a b o r a t o r y t e s t capable of p r e d i c t i n g t h e c l i n i c a l a n a l g e s i c a c t i v i t y of the n a r c o t i a n t a g o n i s t s has y e t t o be s o l v e d . The i n h i b i t i o n of writhingg7 does n o t appear t o be s u f f i c i e n t nor does t h e escape r e s p o n s e e l i c i t e d by t o o t h pulp s t i m u l a t i o n 4 8 . The n a r c o t i c - a n t a g o n i s t a n a l g e s i c s do d e p r e s s the c o a x i a l l y s t h u l a t e d u i n e a p i g ileum and naloxone i s i n e f f e c t i v e i n t h i s I t has been r e p o r t e d that c h o l i n e r g i c mechanisms r e g a r d 949, may be involved i n t h e a c t i o n of t h e s e c o m p o u n d s ~ ~ s o .Thus, t h e p r e v i o u s l y i n a c t i v e n a r c o t i c - a n t a g o n i s t a n a l g e s i c s are c a p a b l e of blocking t h e t a i l - f l i c k r e f l e x i n t h e presence of physostigmine, C h o l i n e s t e r a s e l e v e l s i n t h e b r a i n a l s o appear t o be altered by t h e s e a g e n t s . Analgesic a n t a g o n i s t a c t i v i t y has been reporteds1 i n a s e r i e s of 4 - s u b s t i t u t e d L-acyl-2,3,4,5-tetrahydro-lH-l, 4benzodiazepines XI, Although t h e s e compounds a r e o n l y weak a n t a g o n i s t s t h e y r e p r e s e n t t h e f i r s t n a r c o t i c a n t a g o n i s t s der i v e d from a series devoid of a n a l g e s i c a c t i v i t y .
5
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I
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XII XI Et I V , Weak Analgesics - S i n c e t h e r e i s a c o n s i d e r a b l e o v e r l a p between weak a n a l g e s i c s and Non-Steroidal Anti-Inflammatory Agents, Chapter 21 should a l s o be c o n s u l t e d . A . S a l i c lates - There w a s a continued i n t e r e s t i n asc e r t a i n i n g t e c a u s e of g a s t r i c b l e e d i n g a f t e r t h e i n g e s t i o n of a s p i r i n and o t h e r s a l i c y l a t e s . G a s t r i c e r o s i o n s appear t o r e s u l t when t h e rate of l o s s of s u r f a c e c e l l s exceeds t h e replacement rate52, Sodium s a l i c y l a t e induces a h e a r i n g of t h e v i l l u s e p i t h e l i u m from the u n d e r l y i n g mucosa5’ and i n t e r f e r e s a i t h mucoprotein s y n t h e s i s i n t h e g a s t r o i n t e s t i n a l tract These changes may be caused by a blood borne factor53.
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A n i n t e r e s t i n g l a b o r a t o r y t e s t for m i l d analgesics i n v o l v e s measuring t h e i n f l u e n c e o d r u g s on r e c o v e r y from paininduced motor impairment ’ dogsg6. A p h a m a c o k i n e t i c s t u d y r e l a t e the r a t t o man. of s a l i c y l a t e elimination3’helps B , A n i l i n e Derivatives - A s t r u c t u r e - a c t i v i t y s t u d y of a new series of a l k o x y a n i l i n e d e r i v a t i v e s has been r e p o r t e d a l o n g w i t h a d e t a i l e d workup of one of them58. T h i s compound
( X I I ) a p p e a r s t o have good a n a l g e s i c and a n t i - i n f l a m m a t o r y a c t i v i t y , a s s o c i a t e d w i t h some CNS d e p r e s s a n t e f f e c t s . An a n t i d i u r e t i c e f f e c t w a s d e s c r i b e d f o r acetaminophen59 and i t w a s s u g g e s t e d t h a t t h i s d r u g might be a u s e f u l s u b s t i t u t e f o r vasopressin i n certain p a t i n t s with diabetes insipidus, Evidence w a s a l s o p r e s e n t e d g 0 t o show t h a t a c e t o p h e n e t i d i n has a n t i p y r e t i c a c t i v i t y which i s not dependent on metabolism t o N-acetyl-p-aminophenol.
.
C Pyrazolone D e r i v a t i v e s - Some p y r a z o l o n e d e r i v a t i v e s w e r e prepared which had a n a l g e s i c a c t i v i t y 6 1 . Despite i n t e r e s t i n g s t t u c t u r e - a c t i v i t y r e l a t i o n s h i p s , none of t h e s e compounds w e r e markedly more e f f e c t i v e t h a n pyramidon An i n t e r e s t i n g v a r i a t i o n i s found i n a s e r i e s of i n d a z o l e s g 2 . Those w i t h a dimethylaminopropoxy s i d e c h a i n w e r e t h e most a c t i v e . One of t h e s e , benzydamine ( X I I I ) h a s been e x t e n s i v e l y s t u d i e d
.CH C=O 21 NHR
A: R=OH, R’=Me B: R=R’=H
XIV
p h a r m a c o l o g i c a l l y 6 3 and i s c u r r e n t l y under c l i n i c a l t r i a l . D. M i s c e l l a n e o u s - Buu-Hoi and h i s c o l l e a g u e s 6 4 have p r e pared and t e s t e d a s e r i e s of a r y l a c e t h y d r o x a m i c a c i d s (XIV). Compound XIV-A had b o t h a n t i - i n f l a m m a t o r y and a n a l g e s i c a c t i v i t y w h i l e t h e a c e t a m i d e X I V - B w a s d e v o i d of a n t i - i n f l a m These matory a c t i v i t y y e t r e t a i n e d t h e a n a l g e s i c p r o p e r t i e s . compounds a r e a l s o b e i n g a s s e s s e d i n man. A q u i n o l i n e d e r i v a t i v e , Glaphenin, ( X V ) i s r e p o r t e d t o b e 5-10 times more a c t i v e t h a n a s p i r i n as a n analgesic i n a n i m a l ~ 6 ~ The . compound appeared t o have l i t t l e e f f e c t on t h e C N S , autonomic, and r e s p i r a t o r y systems. Some 6-amino k e t o n e s w e r e a l s o r e p o r t e d t o have a n a l g e s i c a c t i v i t y 6 6 . The c y c l o b u t a n e d e r i v a t i v e ( X V I ) r e p r e s e n t s t h e f i r s t i n s t a n c e of a n a l g e s i c a c t i v i t y f o r a s t r u c t u r e c o n t a i n i n g a non-aromatic cyclobutane r i ng. The a n a l g e s i c e f f e c t s of XVI are n o t a n t a gonized by n a l o r p h i n e . When a Grignard r e a c t i o n w a s a t t e m p t e d w i t h X V I , t h e r i n g c l e a v e d , r e s u l t i n g i n two t y p e s of 6-amino ketones. S e v e r a l compounds of t h i s t y p e had a n a l g e s i c a c t i v i t y
Analgetics
Chap. 4
HN-6-o-CO2CH2 IH20H HOH C02Me
xv
Me
41 -
Harris
#
N(Me)
VMe ) 2CH 21CH2
C6Hll-&H
(Me)
E;,",
XVI I
Me XVI and one of them, (XVII) had a n a l g e s i c a c t i v i t y which w a s antagonized by n a l o r p h i n e . Compound XVI has been s t u d i e d i n t h e c l i n i c and s e e m s t o e x h i b i t a n a l g e s i c and s i d e e f f e c t s s i m i l a r t o aspirin. One of t h e g r e a t d i f f i c u l t i e s encountered i n t h e s t u d y of mild a n a l g e s i c s remains i n t h e i r c l i n i c a l e v a l u a t i o n , An e x p e r i m e n t a l p a i n s t u d y u t i l i z i n g e l e c t r i c a l and thermal s t i m u l i w a s unable t o d i s t i n g u i s h between a s p i r i n and a p l a c e b067. That p a t h o l o g i c a l p a i n s t u d i e s are a l s o n o t wholly t h e answer w a s r e v e a l e d i n a s t u d y by Kantor e t a142
.
42 1.
2. 3.
4. 5. 6.
7. 8.
9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22.
!3.
!4. !5. !6. :7. :8.
9. 0. 1. 2.
3. 4. 5. 6.
Sect.
I
-
CNS Agents
Biel, Ed.
References A.H.Abdu1-Rahman, H.W.Elliot, R.Binks, W.Kung and H,Rapoport, J. Med. Chem. 9, 1 (1966). W.R.Buckett, J. Pharm. Pharmacol. l7, 759 (1965). M.Gates and D.A.Klein, J. Am. Chem. SOC. In Press. . l, O.J.Braenden, N.B.Eddy and H.Halbach, Bull. World Health Org. 3 937 (1955). K.W.Bentley, Personal communication. K.W.Bentley, D.G.Hardy, B.Meek, H.P.Crocker, D.I.Haddlesey, P.A. Mayor, C .F.Howe 11, W .Fulmor , J .E .Lancas ter , J J .Brown G .O.Martin, and R.A.Hardy, J. Am. Chem. SOC. Parts I-VI (1967) in press, E.L.May and N.B.Eddy, J. Med. Chem. 9 , 851 (1966). G.A.Deneau, J.E.Villarrea1 and M.H.Seevers, Addendum I Minutes, Committee on Problems of Drug Dependence (1966). L.S. Harris, Personal communication. F.Clarke, F.D.Block and N.Yokoyama, Symposium, Medicinal Chemistry 153rd. Meeting American Chemical Society, April, 1967. Chem. Abs. 64, 2067 (1966) Patent. J.H.Ager, S.E.Ful1erton and E.L.May, J. Org. Chem. 28, 2470 (1963) and other papers. J.E.Villarrea1 and M.H.Seevers, Addendum 1. Minutes Committee on Problems of Drug Dependence (1967). A.S.Keats, Personal communication. W.R.Martin, Personal communication. Chem. Abs. 64, 12,653 (1966), Patent. T .De Kornfeld. Personal communication. T.Sasaki, K.Kanematsu, Y.Tsuzuki and K.Tanaka, J. Med. Chem. 9, 847 (1966). A.F.Casey and M.M.A.Hassan, J. Pharm. Pharmacol. 19, 17 (1967). E.E.Smissman and M.Steinman, J.Med. Chem. 9 , 455 (1966). C.V.Winder, W.Welford, J. Wax and D.H.Kaump, J.Pharmaco1. Exp. Therap 154, 161 (1966). L.R.Axelrod, P.N.Rao, and D.H.Baeder, J. Am. Chem. SOC. 88, 857(1966) L.R.Axelrod, and D.H.Baeder, Proc. SOC. Exp. Biol. Med. 121, 1184 (1966). D.R.Van Deripe, G.B.Hoey, W.R.Teeters and T.W.Tusing, J.Amer. Chem. SOC. 88,5366 (1966). W.T.Beaver, S.L.Wallenstein, R.W.Houde and A.Rogers, Clin. Pharm. Therap. 7,436 (1966). A.F.Casy and J. Wright, J. Pharm. Pharmacol. 18,677 (1966). D.Van Praag and A.J.Simon, Proc. SOC. Exp. Biol. Med. *- 122, 6 (1966). S.J.Mule, Personal communication. -\ H.S.Bachelard and J.R.Lindsay, Biochem. Pharmacol. 15, 1053 (1966). 1 9 6) . S.J.Mule, J. Pharmacol. Exp. Therap. 154, 370 ( T.Kakunga, H.Kaneto, and K.Hano, ibid. 153, 134 (1966). G.Ungar and M.Cohen, Int. J. Neuropharmacol. 5, 183 (1966). W.D.Notebom and G.C.Mueller, Mol. Pharmacol. 2, 534 (1966). A.A.Smith, M.Karmin, and J.A.Gavitt, Biochem. Pharmacol. 15, 1877 (1966). R.D.Tanz and W,G.Guntheroth, Proc. SOC. Exp. Biol. Med. 122, 754(1966) J.S.Vasko, R.P.Henney, R.K.Brawley, H.N.Oldham and A.G.Morrow, Am. J.
.
-
-
-
Chap. 4
Analgetic s
43 -
Harris
Physiol. 210, 329 (1966). 37. T.W.Redding, C.Y.Bmers, and A.V.Schally, Acta Endocrinol. 2, 391 (1966). 38. P.Lomax and R.George, Brain Research 2, 361 (1966). 39. J.P.Conaghan, M.Jacobsen, L.Rae and J.N.Ward-McQuaid, Brit. J. Anaes. 38, 345 (1966). 40. cT.Beaver, S.L.Wallenstein, R.W.Houde and A.Rogers, Clin. Pharm. Therap. 1,740 (1966). 41. W.W.Filler and N.W.Filler, Obstet. Gynecol. 28, 224 (1966). 42. T.G.Kantor, A.Sunshine, E.Laska, M.Meisner and M.Hopper, Clin. Pharm, Therap. L, 447 (1966). 43. C.D.Witherspoon, C.G.Montaner and B.F.Rusy, Anesthesia and Analgesia 45, 176 (1966). 44. KR.Martin, C.W.Gorodetzky, and T.K.McClane, Clin. Pharm. Therap. 7, 455 (1966). 45. J.Jaffe and A.M.Freedman, Personal communications. 46. H.Blumberg, P.S.Wolf and D.B.Hyman, Proc. SOC. Exp. Biol. Med. 118, 763 (1965). 47. J. Pearl and L.S.Harris, J. Pharmacol. Exp. Therap. 154,319 (1966). 48. C.L.Mitchel1, Arch. int. Pharmacodyn. 164, 427 (1966). 49. E.A.Gyang and H.W.Kosterlitz, Brit. J. Pharmacol. 27, 514 (1966). 50. L.S.Harris, W.Dewey and H.Pars, Fed. Proc. 26, 741 (1967). 51. P,M.Carabateas and L.S.Harris, J. Med. Chem. 2, 6 (1966). 52. D.N.Croft, J. Pharm. Pharmacol. l8, 354 (1966). 53. P.F.Millington and P.W.A.Tove11, Arzneimittel-Forsch. 16,354 (1966). 54. A.Allen and P.W.Kent, Biochem. J. 98, 13 (1966). 55. G.N.Cooper, R.C.Meade, and E.H.Ellison, Arch. Surg. 93, 171 (1966). 56. E.G.Pardo and R.Rodriguez, Life Sci. 5, 775 (1966). 57 E.Nelson, M.Hsnano, G.Levy, J. Pharmacol. Exp. Therap. 2159(1966) 58. L.Coscia, G.DeNatale and P.Causa, Arch. int. Pharmacodyn. 164, 340 (1966). 59. M.L.Nusynowitz and P.H.Forsham, Am. J. Med. Sci. 252, 429 (1966). 60. A.H.Conney, M.Sansur, F.Soroko, R.Koster and J.J.Burns, J. Pharmacol. Exp. Therap. 151, 133 (1966). 61. T.P.Petyunina, Farmakol. i Toksikol. 29, 22 (1966). 62. G.Palazzo, G.Corsi, L.Baiocchi and B.Silvestrini, J. Med. Chem. 2, 38 (1966). 63. B.Silvestrini, A.Garau, C.Pozzatti, and V.Cioli, Arzeimittel-Forsch. &59 (1966). 64. N.P.Buu-Hoi, G.Lambelin, C.Gillet, C.Lepoivre, J. Thiriaux and G. Mees, Nature 211, 752 (1966). 65. M.Peterfalvi, D.Branceni, G.Azadian-Boulanger, L.Chifflot and R. Jequier, Med. Pharmacol. Exptl. l5, 254 (1966). 66. D.L.Goldhamer, A.W.Pircio, A.Wilson, and L.Weintraub, J. Med. Chem. 9, 187 (1966). 67. E.B.Wolff, T.G.Kantor, M.Jarvik, and E.Laska, Clin. Pharm. Therap. 7, 224 (1966).
-
-
Chapter 5. Anorexigenic Agents George I. Poos, McNeil Laboratories, Inc., F o r t Washington, P a .
No breakthroughs were evident in the field of anorexigenic agents during 1966. R e s e a r c h continued to be concentrated on drugs related in s t r u c t u r e to amphetamine. 1 Gylys compared the effect of chlorphentermine (Ia) and amphetamine on food motivated operant behavior i n r a t s . A t equi-anorectic doses, a g r e a t e r d e p r e s s a n t effect on s e v e r a l food motivated schedules was found f o r chlor2 phentermine than f o r amphetamine. Schmitt C 1 e H 2 F - N H R studied the EEG r e c o r d s of rabbits treated with chlorphentermine. At doses of 2.5CH3 10 mg. /kg., which were sedative, high volI tage slow waves were produced. T h e r e was a R = H blocking o r shortening of the a r o u s a l r e b R = COZC2H5 action produced by stimulation of the r e t i cular activating s y s t e m while the recruiting reaction f r o m stimulation of the antero -medial thalamic nucleus was facilitated. An effort to obtain objective m e a s u r e s of the CNS effects of chlorUsing the "alpha blocking phentermine i n humans was unsuccessful. response" (effect of flashes of light on the EEG alpha rhythm) i n normal subjects, chlorphentermine showed no effect i n 65 mg. doses. However, d-amphetamine (15 mg.) and pentobarbital (100 mg.) were a l s o undistinguishable f r o m placebo i n this study. Another potentially useful objective method to d e t e r m i n e CNS stimulation o r depression of anorectics clinically i s that of measuring the "critical flicker fusion frequency". In this test, depressantsdecrease and stimulants i n c r e a s e the d i s ernable frequency of a flickering light (normally ca 32 c y c l e s / s e c . ) . 4D 5,
-
F r o m a survey of the clinical experience with chlorphentermine to date, it a p p e a r s that at effective anorectic doses t h e r e i s a low but about equal incidence of both d e p r e s s a n t and stimulant CNS side effects. 7* The N-ethylcarbamate of chlorphentermine (Ib, cloferex) i s r e o r t ed to be a l e s s toxic, longer acting compound than the parent base. 9, Po A s e r i e s of benzphetamine (IIa) analogs IIb i n which R was H, 4-C1 and 3 - G F 3 , R' was phenyl, halophenyl, furyl, thienyl, etc., and R" w a s H
Ano r exig ens
Chap. 5
R” Q ~ H ~ ~ H - NI - c H ~ -Rl R CH3
R a. b.
H H,C1,CF3
Poos
R’ phenyl phenyl, subst. phenyl, heteroaryl
I1
45 -
R” H H CH3
and methyl w e r e r e p o r t e d as anorexigensl’ i n r a t and dog tests. Activit i e s between phenmetrazine and d - a m p h e t a m i n e w e r e reported. S e v e r a l striking s p e c i e s differences w e r e found. N -ally1 and N-propargyl d e r i v a t i v e s of v a r i o u s methamphetamines a r e claimed i n a Swiss patent to have a p p r e c i a b l e anorexigenic activity i n rats. l 2 S e v e r a l methylated d e r i v a t i v e s of p h e n m e t r a z i n e and ephedrine 13 w e r e shown to have no a n o r e c t i c advantage o v e r the p a r e n t compounds. Clinical trials of RO 4-5282 (N-3 -chloropropylamphetamine 111) a t daily d o s e s of 47 to 140 m g . revealed effects similar to those obtained with phenmetrazine. 14,
111
IV
Rapidly developing a n o r e c t i c t o l e r a n c e i n r a t s h a s been r e p o r t e d f o r p-ethyl- and p-trifluoromethylamphetamine a s well a s 3 -(2 -aminopropyl)genzo[b] thiochene (IV, S K F 6678). l 6 C r o s s t o l e r a n c e with d - a m p h e t a m i n e was not found. The t h r e e compounds studied have r e d u c e d C N S stimulant p r o p e r t i e s and it was suggested that m o r e rapidly developing t o l e r a n c e m a y be a g e n e r a l p r o p e r t y of the l e s s stimulant a n o r e c t i c s . A new aralkoxyguanidine V (U-16, 178 F) h a s b e e n r e p o r t e d to be d-amphetamine i n causing weight l o s s and about about 1/5th a s potent as -
1112th a s active in inhibiting food intake in m i c e . l 7 No stimulant activity was found i n m i c e f o r V up to 40 mg. / k g . , I. P. It blocked maximal electro-shock i n m i c e (ED50 89 mg. / k g . ) and caused a t r a n s i e n t d e p r e s s o r effect i n dogs a t 16 mg. /kg., I . V . 1 -Phenylpiperazine and its m - and p-chloro and methyl d e r i v a t i v e s (VI) w e r e claimed to have about one-half the anorexigenic activity of a m -
46
Sect. I
-
CNSAgents
Biel, Ed.
phetamine with much l e s s acute toxicity and no CNS stimulation. l 8
XD
C
N
-
H
VI X = m and p C1 and CH
-
3
(CzH5)2N
3
kvmHZCH2N
>N
1G2H5)2N
Various diamino -S-triazines with amino alkoxy side chains were claimed i n a Dutch patent to be very potent a n o r exigenic agents with low toxicity and a lack of CNS stimulation. An ED50 of 0.3 mg. /kg. and LD50 of 180 mg. /kg. S . C . i n m i c e was given f o r the m o s t potent compound, 2 , 4 -bis -diethylamino -6 -(2 pyrrolidy1ethoxy)-1, 3, 5-triazine (VII). l 9
-
-
v I1
The effects of anorexi enic agents on lipid metabolism continued to receive attention. F a s s i n j O suggests that by increasing plasma f r e e f a t t y acids, anorexigenic drugs reduce fat s t o r e s and by elevating lipid metabolism, d e c r e a s e appetite i n accord with the lipostatic theory of appetite regulation. On the other hand, when the f r e e fatty acids i n plasma w e r e held a t a low level by the administration of 3 , 5-dimethylisoxazole, the anorectic effect of methamphetamine i n r a t s was not reduced. 21 F u r t h e r r e p o r t s on the effect of anorexigenic a ents on other m e t a bolic f a c t o r s such a s blood glucose, 22 l i v e r glycogen, oxygen consumpt i ~ and n plasma ~ ~ insulin24 appeared. Whether these effects are secondary o r a r e directly involved i n anorexigenic action has not been resolved.
”
An investigation of u r i n a r y excretion i n rats showed that 6791, of chlorphentermine (Ia) was excreted unchanged a f t e r a 20 mg. /kg. dose. 25 Cloferex (Ib) administration i n r a t s led to the p a r t i a l (39700) excretion of chlorphentermine. Phentermine and fenfluramine (VI11)26 were found in the urine to a n extent of only 470 and 6%, respectively, 25 after adrninistration to r a t s .
& YH3
Interesting c e n t r a l anti-ampheta mine effects a r e described f o r tyroH2CHNHCH2CH3 hydroxylase inhibitors such as a-methylVIII tyrosine. 2 7 Since norepinephrine depletors do not antagonize amphetamine and t y r o sine hydroxylase inhibitors have little d i r e c t sedative effect, it i s suggested that s m a l l but c r i t i c a l levels of norepinephrine a t r e c e p t o r s a r e necess a r y for amphetamine to e x e r t both its stimulant and anorexigenic effects. Whether this applies to other anorectic drugs remains to be determined. CF3
Chap. 5
Anor exig ens
47 -
Poos
References
1.
2. 3. J.
4.
5.
9,
J. A. Gylys, A r c h . Intern. P h a r m a c o d y n . , 161, 1 0 2 (1966). H. Schmitt, Therapie, 31, 857 (1966). E. Delamonica, J. W. Shaffer, C . C . Brown and A. A. Kurland, New Drugs, 6, 2 2 4 (1966). P. T u r n e r , J. P h a r m . P h a r m a c o l . , 17, 388 (1965). H. Misiak, R. Z e n h a u s e r n and W. R. Salafia, Psychopharmacologia,
-
457 (1966).
J. V. S m a r t and P. T u r n e r , B r i t . J. P h a r m a c o l . , 26, 468 (1966). J. Am. Med. ASSOC., 165 (1966); P h y s i c i a n ' s D e s k Reference, 2 1 s t Ed., Medical Economics, Inc., Oradell, N. J., 1966, p. 1171. 8. H. I. Russek, Am. J. Med. S c i . , 2 4 9 , 305 (1965). 9. D. Lorenz, P h a r m . Zeitung, 111, 832 (1966). 10. A r s Medici, 21, 96 (1966) LUnlisted Drugs, 19, 2 (1967)]. 11. J. R. B o i s s i e r , R. Ratouis and C. Dumont, Ann. P h a r m . F r a n c . ,
6. 7.
196,
-
24, -
57 (1966).
12. Swiss P a t e n t 393,306, October 30, 1965 to D r . A. Wander. 13. H. Hoffmann, Arch. Intern. Pharmacodyn, 180 (1966). 63, 4 5 4 (1966). 14. H. S. Feldman, J . Med. SOC. New J e r s e y , 15. €3. B r i c a i r e and M. P h i l b e r t , P r e s s e Med., 74, 2695 (1966). 16. C. H. Leonard, G. C . H e i l and E. J. F e l l o w s , F e d . P r o c . , 25, 385 (1966) (Abstr. No. 1106). 17. W. Veldkamp, A. P. T a z e l a a r and H. H. Keasling, P h a r m a c o l o g i s t , 8, 2 2 2 (1966) (Abstr. No. 291). 18. U. S. P a t e n t 3,253,989, May 31, 1966 to A m e r i c a n Cyanamid Company. 19. Netherlands P a t e n t 6,410, 685, M a r c h 15, 1966 to Haco, A . C. 20. C. F a s s i n a , A r c h . Intern. P h a r m a c o d y n . , 161, 410 (1966). 21. A. Fa14 G. Schmidt and U. Schwabe, A r z n e i m i t t e l - F o r s c h . , 16, 733 (1966). 22. K. Opitz, A r c h . Exp. Pathol. P h a r m a k o l . , 250, 279 (1965). 23. K. Opitz, H. G r u e t e r and H. L o e s e r , Arch. Intern. Pharmacodyn. , 161, 183 (1966). 24. L. Gozariu, 0. F l o r e s c u and J. Madar, Endokrinologie, 5 0 ,3 6 (1966). 25. K. Opitz and M. L. Weischer, A r z n e i m i t t e l - F o r s c h . , 16,1311 (1966). 26. J. F. Munro, D. A . Seaton and L. J . P . Duncan, B r i t . w e d . J., 2,
160,
-
624 (1966). 27. A. Weissman, B. K. Roe and S. S. Tenen, J. P h a r m a c o l . Exp. Therap., 151, 339 (1966).
48
Editor:
J o h n G.
-
S e c t i o n I1 Pharmacodynamic A g e n t s Archer, Sterling-Winthrop Research I n s t i t u t e R e n s s e l a e r , N e w York S.
C h a p t e r 6. A n t i h y p e r t e n s i v e Agents T o p l i s s , S c h e r i n g C o r p o r a t i o n , B l o o m f i e l d , N.
J.
-
Catapresan@ The m o s t s i g n i f i c a n t d e v e l o p m e n t i n t h e f i e l d of a n t i h y p e r t e n s i v e a g e n t s d u r i n g 1966 w a s t h e p u b l i c a t i o n o f e x . t e n s i v e a n d d e t a i l e d i n v e s t i g a t i o n s o f a new a n t i h y p e r t e n s i v e a g e n t , 2-(2,6-dichlor~henylamino)-2-imidazoline h y d r o c h l o r i d e ( I ) ( C a t a p r e s a n )?-I3 T h i s compound w a s d e Prelimis i g n e d a n d t e s t e d i n i t i a l l y as a v a s o c o n s t r i c t o r .
c1
.H C 1 I
I1
n a r y c l i n i c a l t e s t i n g by i n t r a n a s a l a d m i n i s t r a t i o n produced marked p r o l o n g e d s e d a t i o n , a l o w e r i n g o f b l o o d p r e s s u r e , These o b s e r v a t i o n s b r a d y c a r d i a a n d d r y n e s s o f t h e mouth. led t o extensive i n v e s t i g a t i o n s of t h e substance i n experim e n t a l a n i m a l s a n d i n man w h i c h e s t a b l i s h e d t h a t t h e marked a n t i h y p e r t e n s i v e e f f e c t w a s i t s most i m p o r t a n t p r o p e r t y . Two h u n d r e d a n d f i f t y i m i d a z o l i n e d e r i v a t i v e s w e r e s y n t h e s i z e d a n d t e s t e d p h a m a c o l o g i c a l l y , b u t n o n e w a s more e f f e c S l i g h t s t r u c t u r a l changes c o n s i d e r t i v e t h a n Catapresan&. a b l y d i m i n i s h e d or a b o l i s h e d t h e b l o o d p r e s s u r e l o w e r i n g effect. C l i n i c a l t e s t i n g of twenty analogs w a s c a r r i e d out, however, a l l o f t h e s e were f o u n d t o b e less a c t i v e t h a n t h e p a r e n t c omp ound.5 C a t a p r e s a n @ shows a s t r u c t u r a l r e s e m b l a n c e t o g u a n e t h i d i n e t y p e compounds, p a r t i c u l a r l y b e t h a n i d i n e (11), a n d t o i m i d a z o l i n e s b o t h o f t h e v a s o c o n s t r i c t o r c l a s s s u c h as
Chap. 6
Topli s s
Anti hyper t en s i v e s
x y l o m e t a z o l i n e , and a l s o t o phentolamine, pressure lowering effect.'
49 -
noted f o r i t s blood
P h a r m a c o l o g i c a l t e s t s ' showed t h a t upon i n t r a v e n o u s a d m i n i s t r a t i o n t o d o g s i n a d o s a g e r a n g e o f 1 0 - 3 0 7 / k g a sedat i v e e f f e c t w a s produced along with a blood pressure decrease o f l o n g d u r a t i o n accompanied by b r a d y c a r d i a , i n h i b i t i o n o f blood p r e s s u r e r a i s i n g c a r d i o v a s c u l a r r e f l e x e s and d e c r e a s e of cardiac output. C o n t r a c t i o n o f t h e n i c t i t a t i n g membrane i n c a t s , induced by preganglionic e l e c t r i c a l stimulation, w a s not inhibited. No a d v e r s e e f f e c t s on t h e myocardium w e r e seen i n experiments with t h e heart-lung preparation. The compound d i d n o t c a u s e a d e c r e a s e i n t h e n o r a d r e n a l i n e c o n t e n t Some s y m p a t h o m i m e t i c e f f e c t s w e r e o b s e r v e d of the rat heart. i n t h e l o w e r dosage r a n g e and i n h i b i t i o n o f u l c e r f o r m a t i o n and a c i d s e c r e t i o n i n t h e r a t stomach were o b s e r v e d m a i n l y w i t h d o s e s h i g h e r t h a n 30-1007 / k g . T o x i c o l o g i c a l s t u d i e s , b o t h s u b a c u t e and c h r o n i c i n r a t s and d o g s , and t e r a t o l o g i c e x p e r i m e n s i n r a t s , mice and rabb i t s were c o n d u c t e d w i t h C a t a p r e s a n a n d t h e r e s u l t s d e s c r i b e d as f a v o r a b l e e v e n w i t h h i g h d o s e l e v e l s a n d a f t e r l o n g adminC 1 4 s t u d i e s 3 showed t h a t t h e compound i s r e a d i l y istration4. Two-thirds a b s o r b e d by t h e r a t a f t e r o r a l a d m i n i s t r a t i o n . o f t h e d o s e was e x c r e t e d i n t h e u r i n e a n d o n e - t h i r d i n t h e feces. Elimination w a s apparently complete during t h e f i r s t f o r t y - e i g h t h o u r s w i t h 60-70$ o f t h e s u b s t a n c e e x c r e t e d u n changed.
6
l3 C l i n i c a l s t u d i e s on C a t a p r e s a n Q h a v e b e e n r e p o r tse'd'6' ' ' ' which i n d i c a t e t h a t a r e l i a b l e and s u b s t a n t i a l l o w e r i n g of b l o o d p r e s s u r e c a n be o b t a i n e d upon o r a l a d m i n i s t r a t i o n i n d i v i d e d d o s e s o f 225-1350 Y o f t h e d r u g t o h y p e r t e n s i v e p a tients. The e f f e c t s c a n b e s e e n i n c a s e s o f p r i m a r y a n d s e c o n d a r y , b e n i g n or m a l i g n a n t h y p e r t e n ~ i o n l ~ .The d e g r e e o f p r e s s u r e r e d u c t i o n a t t a i n a b l e w a s a b o u t t h e same as t h a t from a - m e t h y l d ~ p a l ~ . S i d e e f f e c t s e n c o u n t e r e d were d r y n e s s o f t h e mouth a n d s e d a t i o n , p a r t i c u l a r l y a t h i g h e r doses.6 s10,1413 A s l i g h t , d o s e r e l a t e d d e c r e a s e o f t h e p u l s e r a t e w a s noted.lo There w a s l i t t l e e f f e c t on o r t h o s t a t i c b l o o d pressure6,11J1" and f e w d i g e s t i v e d i s t u r b a n c e s ? R e p o r t s on t h e e f f e c t o f t h e d r u g on r e n a l f u n c t i o n were n o t e n t i r e l y c o n s i s t e n t . Both unchanged13 and r e d u c e d l l p - a m i n o h i p p u r i c a c i d and i n u l i n c l e a r a n c e s were r e p o r t e d . No n o t a b l e c h a n g e i n u r i n e volume and e x c r e t i o n o f e l e c t r o l y t e s w a s s e e n 6 b u t i n r e n a l and e s s e n t i a l hypertension, a s t a t i s t i c a l l y s i g n i f i c a n t r i s e of t h e serum c o n c e n t r a t i o n o f sodium and c h l r i d e i o n s o c c u r r e d . The a n t i h y p e r t e n s i v e e f f e c t o f C a t a p r e s a n & w a s p o t e n t i a t e d b y t h e a d d i t i o n of d r u g s which promoted r e n a l s a l t e x c r e ti0n.l"
-
50
Sect. I1
- P h a r m a c o d y n a m i c Agents
A r c h e r , Ed.
Some interesting comparisons ha e been drawn between the characteristic actions of Catapresan' and reserpine, a-methyl dopa and guanethidine.5 Similarities and distinctions were noted in each case. The conclusi n was reached that the mechanism of action of CatapresanO has not, as yet, been clarified and the drug has characteristics such that it cannot be adequately classified in any o f the known drug groups now used in antihypertensive therap&=
-
A number of cyclic hindered Ganglionic Blocking Agents amines substituted on the a-carbon with ethynyl, vinyl and alkyl groups have been synthesized and their antihypertensive properties compared with a corresponding series of open chain compounds. It was found that the open chain compounds were
I11
IV
V
generally more potent in their hypotensive effect. For ex(IV) and 2ample, 2-ethynyl-1,2,5,5-tetramethylpyrrolidine ethynyl-l,2,6,6-tetramethylpiperidine (V) produced a mean average pressure drop in hypertensive rats of 676 at 20 mg/kg and 5 % at 5 mg/kg, respectively, compared to a pressure drop of 11% at 5 mg/kg produced by the open chain analog 3-(N-tbutylmethylamino)-3-methyl-l-butyne (III). The results appear to be consistent with the hypothesis that the principal factor controlling activity is the degree of shielding of the basic nitrogen atom provided by alkyl groups substituted on the two adjacent carbon atomsl4. The ganglionic blocking action of several methylpiperidines as their hydrochlorides or quaternary methosalts has been studied. The most potent compound was the secondary 2,2,6,6-tetramethylpiperidine. The ganglionic blockade produced by secondary and tertiary amines was found to be of long duration. The quaternary compounds were more active in equimolar doses but their effects were of shorter duration. It was demonstrated that the presence of at least three methyl groups on the a-carbon atoms of the piperidine ring is not absolutely necessary to confer ganglionic blocking properties on the molecule, although it has been confirmed that increasing the number of methyl substituents of the 2-
-
Chap. 6
Antihypertensives
To p l i s s
51 -
a n d 6- p o s i t i o n s a u g m e n t s t h i s e f f e c t . The g a n g l i o n i c b l o c k a d e p r o d u c e d w a s shown t o b e o f t h e n o n d e p o l a r i z i n g t y p e . 1 5
A s e r i e s of cyclobutanolamines (VI,
where R l R 2 R 3 a n d R,=
H or a l k y l ) h a s b e e n f o u n d t o p o s s e s s g a n g l i o n i c b l o c k i n g a n d h y p o t e n s i v e a c t i v i t y and t h e i m p o r t a n c e of t h e e f f e c t o f t h e a l k y l groups surrounding t h e b a s i c n i t r o g e n on a c t i v i t y h a s b e e n demonstrated. More d e t a i l e d s t u d i e s on o n e member o f t h e s e r i e s , t r a n s 2,2,4,4-tetramethyl(cH3)2NQo 3-dimethylaminocyclobutanol ( V I , H R1=R2=R3=R4=CH3) (RP 9 0 4 ) w e r e described. T h i s compound, w h i c h R1 R2 underwent r a p i d o r a l a b s o r p t i o n , w a s shown t o b l o c k p r e g a n g l i o n i c VI s t i m u l a t i o n and t o i n d u c e p e r i pheral vasodilatation.16
+-
G u a n e t h i d i n e Analo s @-Heptamethyleneiminoethylaminoguanid i n e s u l f a t e , EX4 9 l A , ( V I I ) h a s b e e n s y n t h e s i z e d and t e s t e d on t h e b a s i s t h a t i n t e r p o s i t i o n o f t h e amino g r o u p b e f o r e t h e q u a n i d i n e m o i e t y i n t h e s t r a i g h t c h a i n p o s i t i o n o f t h e molec u l e m i g h t r e d u c e or e l i m i n a t e t h e a c u t e s y m p a t h o m i m e t i c action of guanethidine. T h i s p o s s i b i l i t y may b e r e a l i z e d s i n c e t h e compound d e p l e t e d c a t e c h o l a m i n e s from t h e r a t venNH t r i c l e but did not exhibit a II sympathomimetic e f f e c t due t o N- CHH$. 2NmH-C -NH i! a c u t e r e l e a se o f c a te cholamines i n a c t i v e forms t h u s d i f f e r i n g 1 / 2 H2S04 i n t h e l a t t e r r e s p e c t from guanethidine. Another d i s t i n c VII t i o n was t h a t the tyramine-like e f f e c t o f guanethidine, seen after parenteral administration, w a s not obtained with V I I . Otherwise, t h e pharmacologic e f f e c t s o f t h i s analog appear t o be i d e n t i c a l with t h o s e of guanethidine i n producing adrenergic neurone blockade, having n o a p p a r e n t e f f e c t on o u t - f l o w f r o m c e n t r a l s y m p a t h e t i c s t r u c t u r e s and showing t r a n s i e n t d i r e c t v a s o d i l a t o r y e f f e c t s . 1 7
C
C i s - c i n n a m y l g u a n i d i n e s u l f a t e , Su 13686, w a s f o u n d t o b e an o r a l l y a c t i v e h y p o t e n s i v e a g e n t i n b o t h a n e s t h e t i z e d and u n a n e s t h e t i z e d normotensive dogs and i n u n a n e s t h e t i z e d r e n a l O n s e t o f a c t i o n was r a p i d . The compound h y p e r t e n s i v e dogs. a l s o reduced t h e b l o o d p r e s s u r e o f a n e s t h e t i z e d c a t s and r a b bits. The p r e s s o r e f f e c t s o f e p i n e p h r i n e a n d n o r e p i n e p h r i n e were e n h a n c e d , w h e r e a s t h o s e f r o m a m p h e t a m i n e w e r e i n h i b i t e d . D a i l y o r a l a d m i n i s t r a t i o n o f 2 mg/kg o f t h e d r u g t o u n a n e s t h e t i z e d r e n a l h y p e r t e n s i v e dogs f o r t w e l v e d a y s r e d u c e d
Sect. I1 - P h a r m a c o d y n a m i c A g e n t s
52
I
A r c h e r , Ed
mean a r t e r i a l p r e s s u r e b y 2 1 mm Hg.18
A s p a r t o f a program t o ex.plore t h e e f f e c t o f s u b s t i t u t i n g t h e isoquinuclidine moiety f o r o t h e r groups i n various and N- [ 3 - ( g u a n i d i n o ) p r o p y l I d r u g s , N - [ 2 - ( g u a n i d i n o ) e t h y l 1i s o q u i n u c l i d i n e s u l f a t e s ( V I I I , n = 2 , 3 ) w e r e s y n t h e s i z e d as analogs of guanethidine. Both compounds, when e v a l u a t e d b y intravenous administration t o c j ( c H z ) n :i H - C - N H 2 t h e a n e s t h e t i z e d dog, were f o u n d t o be l e s s a c t i v e t h a n 1 / 2 H2S04 guanethidine i n lowering blood p r e s s u r e and t o c a u s e s e v e r e side effects.lS VIII
W"
The p h a r m a c o l o g i c a l p r o p e r t i e s o f N I N " - d i m e t h y l - 1 , 2 , 3 , 4 t e t r a h y d r o i s o q u i n o l i n e 2 - c a r b o x a m i d i n e h y d r o c h l o r i d e , P4746, ( I X , R' =R"=CHa,X=H) h a v e b e e n d e s c r i b e d . T h i s compound, w h i c h i s t h e N'N" dimethyl d e r i v a t i v e o f d e b r i s o q u i n ( I X , R'=R"=X=H), w a s found t o lower t h e blood pressure of conscious hypertens i v e d o g s on c h r o n i c a d m i n i s t r a -NHRL X tion. Other o b s e r v a t i o n s i n d i NR cated t h a t t h i s a c t i o n i s proba b l y d u e t o a r e d u c t i o n i n symp a t h e t i c t o n e as a c o n s e q u e n c e IX o f p o s t - g a n g l i o n i c sympathe ti c blockade. I n acute experiments t h e compound e l i c i t e d a h y p e r t e n s i v e r e s p o n s e , s i m i l a r t o guanethidine. It w a s less e f f e c t i v e t h a n g u a n i s o q u i n ( I X , R'=R"=H, X=Br ) i n lowering myocardial norephinephrine levels?'
-
The c a r d i a c a n d r e n a l hernodynamic e f f e c t s o f d e b r i s o q u i n s u l f a t e have been s t u d i e d i n h y p e r t e n s i v e p a t i e n t s and found t o be s i n i l a r t o t h o s e o b s e r v e d w i t h g u a n e t h i d i n e and t h e ganglionic blocking agents. Lowered b l o o d p r e s s u r e a s s o c i a t e d w i t h reduced c a r d i a c o u t p u t and r e n a l b l o o d f l o w a r e a p p a r e n t l y c h a r a c t e r i s t i c o f t h e hernodynamic p a t t e r n o f i n h i b i t i o n o f t h e p e r i p h e r a l s y m p a t h e t i c n e r v o u s system?' A new c l i n i c a l s t u d y o f g u a n o c l o r , i i 2 - ( 2 , 6 - d i c h l o r o p h e n o x y ) e t h y l 1 a m i n o 3 g u a n i d i n e s u l f a t e , i n 35 h y p e r t e n s i v e s u b d e c t s h a s been described.22
P a . r t I o f a r e v i e w on g u a n e t h i d i n e c o v e r i n g t h e d i s c o v e r y , development, chemical s t r u c t u r e , p h y s i c a l p r o p e r t i e s and p h a r m a c o l o g i c a l a c t i o n s o f t h i s d r u g h a s a p p e a r e d . 23 Pargyline
-
The e f f e c t o f p a r g y l i n e on b l o o d p r e s s u r e i n
Antihypertensive s
Chap. 6
Topli s s
53 -
s p i n a l and d e c e r e b r a t e c a t s h a s been s t u d i e d . It w a s found t h a t t h e a c u t e l y administered drug produced a slowly developi n g hypertensive e f f e c t of long duration i n s p i n a l c a t s b u t u n d e r s i m i l a r c o n d i t i o n s i n d e c e r e b r a t e a n i m a l s , t h e r e w a s no e f f e c t on b l o o d p r e s s u r e , T h e s e e x p e r i m e n t s were h e l d t o i n d i c a t e t h a t t h e p r e s e n c e of t h e medullary vasomotor c e n t e r i s necessary t o prevent t h e p e r i p h e r a l hypertensive a c t i o n of ~ a r g y l i n e . 2 ~ A r e p o r t a p p e a r e d d e a l i n g w i t h t h e pharmacodynamics o f p a r g y l i n e i n t h e r a t and cat.** A c l i n i c a l study c o n c e r n i n g t h e e f f e c t o f p a r g y l i n e on b l o o d p r e s s u r e and mood of 8 3 h y p e r t e n s i v e p a t i e n t s w i t h m o d e r a t e t o s e v e r e e s s e n t i a l h y p e r t e n s i o n was d e s c r i b e d ? ’
-
Mebutamate The mechanism o f t h e h y p o t e n s i v e a c t i o n o f mebutamate w a s i n v e s t i g a t e d i n c r o s s c i r c u l a t i o n e x p e r i m e n t s i n a n e s t h e t i z e d dogs. The r e s u l t s s u g g e s t e d t h a t t h e i n i t i a l a n d t r a n s i e n t h y p o t e n s i o n may b e l a r g e l y d u e t o t h e d i r e c t v a s o d i l a t o r a c t i o n and t h a t t h e s u s t a i n e d e f f e c t may b e a c counted f o r by an i n h i b i t i o n o f t h e s y m p a t h e t i c vasomotor t o n e a t t h e s p i n a l and g a n g l i o n i c l e v e l s . 2 6
-
Amino ~A c i d Enzyme I n h i b i t o r s A comparative c l i n i c a l study o f t h e antihypertensive e f f e c t s e l i c i t e d by intravenous i n J e c t i o n o f a - m e t h y l d o p a a n d a - m e t h y l - g - t y r o s i n e h a s shown, contrary t o previous reports, t h a t t h e l a t t e r agent has a l o n g e r d u r a t i o n o f a c t i o n i n e s s e n t i a l h y p e r t o n i a and a l s o a more p r o n o u n c e d o r t h o s t a t i c e f f e c t . 2 8 F i n d i n g s o f autoimmune h a e m o l y t i c a n e m i a a s s o c i a t e d w i t h a - m e t h y l d o p a t h e r a p y h a v e b e e n d e s c r i b e d Z 9 , 3 0 and a c a s e o f h y p e r t e n s i v e r e s p o n s e t o a-methyldopa h a s been reported?’
-
A review of the treatment A n t i h y p e r t e n s i v e D i u r e t i c Drugs of hypertension with a n t i h y p e r t e n s i v e d i u r e t i c drugs has appeared. I n a c l i n i c a l s t u d y i n 2 1 p a t i e n t s on t r i a m t e r e n e (2,4,7-triamino-6-phenylpteridine), t h e d r u g had a n i n c o n s i s t e n t a n t i h y p e r t e n s i v e e f f e c t on t h e s y s t o l i c b l o o d p r e s s u r e which w a s m i n i m a l i n m o s t p a t i e n t s , b u t i n c o m b i n a t i o n w i t h h y d r o c h b t h i a z i d e appeared t o be u s e f u l i n p r o v i d i n g a s l i g h t a d d i t i o n a l s y s t o l i c blood p r e s s u r e r e d u c t i o n and an i n c r e a s e i n serum p o t a s s i u m l e v e l s . 3 3
-
It h a s b e e n r e p o r t e d t h a t 1 4 o f 1 6 p a t i e n t s w i t h Diazoxide s e v e r e c h r o n i c h y p e r t e n s i o n , who had become u n r e s p o n s i v e t o a - m e t h y l d o p a , g u a n e t h i d i n e and h y d r a l a z i n e , r e s p o n d e d t o a 20 d a y i n t r a v e n o u s r e g i m e n o f 3 0 0 mg d o s e s o f d i a z o x . i d e w i t h a s u b s t a n t i a l mean a r t e r i a l p r e s s u r e d r o p a c c o m p a n i e d i n some c a s e s by c l e a r a n c e o f r e t i n o p a t h y , d e c r e a s e o f c a r d i a c s i z e and l e s s e n i n g o f c o n g e s t i v e h e a r t f a i l u r e . Subsequently t h e blood p r e s s u r e could be c o n t r o l l e d by a d m i n i s t r a t i o n o f c h l o r Thus i t t h a l i d o n e p l u s r e s e r p i n e f o r a p e r i o d o f 30 months.
54 -
Sect. I1
-
P h a r m a c o d y n a m i c ,Agents
A r c h e r , Ed.
would seem that acute repeated reductions of arterial pressure during the 20 day period of diazoride administration modified the severity of the vascular dis as possibly by readjusting the so-called pressure barostat. s4,s 5
Beta Adrenergic
-
Receptor Blocking Agents The proceedings of a symposium on this subject have been published in which the use of propanolol (l-isopropylamino-j-(l-napthoxy)-2-propanol hydrochloride) in hypertension is OH disc~ssed.~" The pharmacological I properties of a new adrenergic 3''( )2 p -recep tor antagoni st 1-i sopro p ylamino 3 ( 3 t01ylo x.y) 2 -propa HC1 no1 hydrochloride (ICI 45 7 6 3 ) (X) have been described. 33
-- -
.
CH3
,
-
--
X
-
Peptides Some bradykinin analogs have been synthesized and biologically evaluated. The 8-~-trifluoromethylphenylalanine analog was found to be about 1 . 5 times as active as bradykinin in lowering guinea pig blood pressurebut only one-half as active in lung bronchoconstriction, thus supporting the idea that different receptor sites are involved for the hypotensive and bronchoconstrictive effects. The proceedings of a symposium on hypotensive peptides have been published.3a
-
A series of mesoionic compounds known as V-ox.atriazoles (XI) has been synthesized and p - 0 shown to produce a hypotensive effect when administered intraR-N @ venously to anesthetized dogs at The blood a dose of 5 mg/kg. \N/O pressure reduction ranged from about 6 $ (R=1,3-dimethylbutyl) XI to 3O$ (R=cyclohexyl) and the duration of action from one to two hours. Some of the hypotensive effects of these compounds may be due to competition with norepinephrine for adrenergic receptors.40 Other Antihypertensive Agents
1
Some N-substituted phenoxyethylamines (XII) have been prepared and their hypotensive effects evaluated in anesthetized normotensive cats and neurogenically hypertensive dogs. A study of the structure-activity relationships revealed that the 2-(2-methoxyphenoxy) ethylamino moiety is necessary for maximum effect. Three members of the series; XII, R = CH2CHOHCH20CH2CH=CH2, (CH2)4C6H40CH3 p and (CH2)3OCeH3-2,5
-
Chap. 6
Antihypertensive s
Toplis s
55 -
(OCH3)2, were s u b j e c t e d t o c l i n i c a l t r i a l s i n which a n t i h y p e r t e n s i v e
XI1
a b i yclo[4.4.0]decanes A number o f s u b s t i t u t e d 1 , 4 - d i h a v e b e e n s y n t h e s i z e d a n d shown t o l o w e r t h e b l o o d p r e s s u r e of 5 , 5 - d i a l b l b a r b i t u r i c a c i d a n e s t h e t i z e d c a t s upon i n t r a It appears t h a t t h e hypotensive venous a d m i n i s t r a t i o n . a c t i v i t y i s primarily a t t r i b u t able t o the 1,4-diazabicyclo [ 4 . 4 . 0 ] d e c a n e s y s t e m b u t may b e q u a n t i t a t i v e l y modified by t h e nature of t h e s u b s t i t u e n t s . The most p o t e n t compounds i n t h e X, R series are X I I I , R = CH(C6Hs)z and CH2CH2NH2. The mechanism XI11 of a c t i o n remains t o be d e t e r mined b u t p r o b a b l y i s n o t g a n g l i o n i c blockade.42
-
bq -
Ex.perimenta1 r e s u l t s r e l a t i n g t o t h e h y p o t e n s i v e a c t i v i t y o f 3'-me t hoxy-4'- [ 4 ( 4 -phen yl -1 - p i p e r a z i n y l ) b u t o x y 1 a c e t ophenone ( X I V ) as t h e m o n o h y d r o c h l o r i d e ( S u - 1 4 5 4 2 ) o r d i h y d r o c h l o r i d e (SU-13396) i n normotensive a n d r e n a l h y p e r t e n s i v e dogs have been r e p o r t e d . T h e s e were i n t e r p r e t e d as i n d i c a t i n g t h a t Su-14542 d o e s n o t a c t b y g a n g l i o n i c b l o c k a d e b u t d o e s p o s s e s s i3-adrenergic s t i m u l a t i n g a c t i v i t y . 4 3 COCH3 Other i n v e s t i g a t o r s p r e s e n t e d d a t a f r o m which t h e y c o n c l u d e d t h a t Su-14542 i s a p o t e n t areceptor blocking agent but not a stimulant of the p-receptors CH30 I o f c a t , r a b b i t o r dog h e a r t s . I t was s u g g e s t e d t h a t t h e h e a r t 0 ( CH.2) 3s t i m u l a t i o n previously observed 1__/N-C6H= following a d m i n i s t r a t i o n of XIV Su-14542 i s m e d i a t e d r e f l e x l y as compensation f o r t h e f a l l i n a r t e r i a l blood p r e s s u r e r e s u l t i n g f r o m t h e i n t e n s e a - r e c e p t o r b l o c k a d e p r o d u c e d b y t h i s compound.44 The e f f e c t s o f Su-14542 on c a r d i a c o u t p u t a n d c o r o n a r y b l o o d flow4' a n d on f e m o r a l r e n a l blood have been d e s c r i b e d .
-
b
I F
Some c o n d e n s e d a l i c y c l i c l e p i d i n e s (XV, n = 3 , 4 , 5 ) h a v e been t h e s u b j e c t o f a p h a r m a c o l o g i c a l s t u d y i n comparison
56 -
Sect. XI
-
P h a r m a c o d y n a m i c Agents
A r c h e r , Ed.
with l e p i d i n e (4-methylquinoline) i t s e l f a n d shown t o e x . h i b i t a h y p o t e n s i v e r e s p o n s e i n r a t s and cats.
47
xv A new c l i n i c a l s t u d y o f t h e a n t i h y p e r t e n s i v e a c t i o n o f p r o g e s t e r o n e i n 17 h y p e r t e n s i v e p a t i e n t s has b e e n r e p o r t e d . A s i g n i f i c a n t d e c r e a s e o f b o t h s y s t o l i c and d i a s t o l i c b l o o d p r e s s u r e s u p o n d a i l y a d m i n i s t r a t i o n o f 1 0 0 t o 3 0 0 mg o f The l o w e r i n g o f progesterone intramuscularly Y a s observed. b l o o d p r e s s u r e was r e l a t e d t o a r e d u c t i o n o f p e r i p h e r a l r e sistance. The a u t h o r s d o n o t p r o p o s e p r o g e s t e r o n e as a therapeutic agent f o r a r t e r i a l hypertension b u t believe t h a t i t s a c t i o n i s of i n t e r e s t i n considering t h e pathological physiology of primary hypertension.*8
-
A t h e o r y o f h y p e r t e n s i o n , i n which a s e t o f e x . i s t i n g General i d e a s h a v e b e e n i n t e g r a t e d i n a new way, h a s b e e n p r e s e n t e d where i t i s s u g g e s t e d t h a t a d a p t a t i o n o f t h e b a r o r e c e p t o r s t o t h e h i g h a r t e r i a l p r e s s u r e might be t h e primary f a c t o r The c l i n i c a l f e a t u r e s o f b e n i g n a n d m a l i g i n t h e disease. n a n t h y p e r t e n s i o n and t h e change from o n e t o t h e o t h e r c o u l d Therapeutic implications of b e a c c o u n t e d f o r on t h i s basis. t h e h y p o t h e s i s a r e c o n s i d e r e d , 4 s and i n t h i s r e g a r d i t i s i n t e r e s t i n g t o c o n s i d e r s t u d i e s p r e v i o u s l y discussed.34’3s
The r o l e o f r e n i n i n r e n a l h y p e r t e n s i o n h a s b e e n d i s -
cussed and a h y p o t h e s i s p u t forward c o n t a i n i n g t h e n o v e l proposal t h a t t h e blood pressure lowering capacity of t h e kidney i s d i r e c t l y p r o p o r t i o n a l t o i t s r e n i n content.=’
A t w e n t y y e a r c l i n i c a l f o l l o w - u p s t u d y on e s s e n t i a l hypertension was reported.5l References
1.
W. H o e f k e a n d W . K o b i n g e r , A r z n e i m i t t e l - F o r s c h . , 1038 ( 1 9 6 6 ) .
2.
G. D. 0. W. K. E.
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4. 5. 6. 7.
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GogolAk a n d Ch. Stumpf, i b i d . , l6, 1 0 5 0 ( 1 9 6 6 ) . R e h b i n d e r a n d $1. D e c k e r s , i b i d . , l6, 1 0 5 2 ( 1 9 6 6 ) . von D e l b r s c k , i b i d , 16, 1053 ( 1 9 6 6 ) . G r a u b n e r a n d M. Wolf, i b i d . , 13, 1055 ( 1 9 6 6 ) . K o c h s i e k a n d H. F r i t s c h e , i b i d . , Id, 11-54 ( 1 9 6 6 ) . Deisenhammer a n d E. M. K l a u s b e r g e r , i b i d . , 1161 (1966).
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ibid.,
H. E h r i n g e r , i b i d . ,
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(1966)*
H. K n o b l o c h a n d H . Morr, i b i d . , 1 6 1 1 7 4 ( 1 9 6 6 ) . H. F r a n k a n d K. von L o e w e n i c h - L a a ’ s . D e u t s c h . Med. Wochschr., 1680 ( 1 9 6 6 ) . R. Makabe, i b i d . , 2 , 1686 (1966). K. D. Bock, V. H e i m s o t h , P. M e r g u e t a n d J, S c h s n e r m a r k , i b i d . , 91, 1 7 6 1 ( 1 9 6 6 ) . N , R . E a s t o n , F, G. H e n d e r s o n , W . J. McMurray a n d ru’. J. L e o n a r d , J . Med. Chem., 2, 465 ( 1 9 6 6 ) . K. V i d a l - B e r e t e r v i d e , J. M. M o n t i , R , R u g g i a a n d li. T r i n i d a d , J . P h a r m a c o l . Exp. T h e r a p . , 152, 181 (1966). A. W . P i r c i o , P. J. P a r i s e k , E. J. G o s k i n s k y a n d C . S . K r e m e n t z , A r c h . i n t . P h a r m a c o d y n . 13, 4 2 7 ( 1 9 6 6 ) . I. B o t t o n , W. J. K i n n a r d a n d J. P. B u c k l e y , J. F h a r m a c o l . Exp. T h e r a p . , 152, 243 (1966). W. E. B a r r e t t , R . R u t l e d g e , R . P o v a l s k i a n d A . J. Plummer, Pharmacologist, & 1 8 2 (1966). F. J. V i l l a n i and C . A . E l l i s , J. Med. Chem., 9, 1 8 5
91,
(1966 1
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29
p.
Antihypertensive s
S c r i a b i n e , K. D. B o o k e r , J. N. P e r e i r a , W . K. McShane a n d R. C . Koch, A r c h . I n t . P h a r m a c o d y n . , E , 435 ( 1 ? 6 6 ) . G. O n e s t i , D . L a S c h i a z z a , A. N. B r e s t a n d J. H. Moyer, C l i n . P h a r m a c o l . T h e r a p . , ‘7, 1 7 ( 1 9 6 6 ) . J. V. Hodge, B r i t . Med. J., 981 ( 1 9 6 6 ) . H. J. Sah, P.P.T. S a h a n d S. A. P e o p l e s , A r z n e i m i t t e l Forsch., 53 (1966). T. E. L y n e s , J. Pharm. I h a r m a c o l . @, 759 ( 1 9 6 6 ) . A. C e s s i o n - F o s s i o n , Arch. i n t . P h a r m a c o d y n . 161, 2 9 8 (1966 1 V. B e a t o , R . D u a r t e a n d H. A l v a r e z d e l P u e r t o , C u r r . T h e r a p . Res., 515 (1966). H. H. Wang, S. Markee, N. Kahn, E. M i l l s a n d S. C . Wan&, J. P h a r m a c o l . Exp. T h e r a p . , 151, 285 ( 1 9 6 6 ) . H. J. H o l t m e i e r , A. v . K l e i n - W i s e n b e r g a n d F. M a r o n g i n , D e u t s c h . Med. W o r c h s c h r . , 91, 1 9 8 ( 1 9 6 6 ) . K O C . C a r s t a i r s , A. B r e c k e n r i d g e , C. T. D o l l e r y a n d S . M. W o r l l e d g e , L a n c e t , i i , 1 3 3 ( 1 9 6 6 ) . S o M. W o r l l e d g e , K. C . C a r s t a i r s a n d J. V. D a c i e , i b i d . , ii, 1 3 5 ( 1 9 6 6 ) . R . J. L e v i n e a n d B. S , S t r a u c h , New E n g l . J. Med., 2 7 5 , 946 ( 1 9 6 6 ) . R. L. Wolf, M. M e n d l o w i t z , J. Roboz a n d S. E. Gitlow, Am. H e a r t J., 72, 6 9 2 ( 1 9 6 6 ) . R. E. S p i e k e r m a n , K. G. B e r g e , D. L. T h u r b e r , S. W. Gedge a n d W. F. McGuckin, C i r c u l a t i o n , 524 (1966). N. K a k a v i a t o s , M. D a v i d o v a n d F. A. F i n n e r t y , Jr., C l i n i c a l Research, 8 2 (1966). F. A. F i n n e r t y , Jr., N. K a k a v i a t o s a n d M. D a v i d o v , C i r c u l a t i o n , 34, S u p p l e m e n t III, 1 0 1 ( 1 9 6 6 ) . A.
16,
-
8,
2,
14,
-
58
S e c t . I1
38 39
R.
9
40. 41.
420 43 44.
J.
G.
z,
-
(1966 1
45
0
46.
47 48.
49 50 51
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C a r d i o l , l8, 303 (1966). S h a n k s , T o M. Wood, A. C . D o r n h o s t a n d M. L. C l a r k , Nature, 88 ( 1 9 6 6 ) E. N i c o l a i d e s a n d M. L i p n i k , J. Med. Chem., 2, 958 ( 1 9 6 6 ) . Hypotensive Peptides. Proceedings of t h e I n t e r n a t i o n a l E d . b y E. G. Symposium, F l o r e n c e , I t a l y , O c t . 1965. Erdos, N. Back, F. S i c u t e r i a n d A. F. W i l d e , S p r i n g e r V e r l a g , I n c . N e w York, N. Y. 1966. L. B. K i e r , A. Al-Shamma, D. C a m p b e l l , P. N . P a t i l a n d A. Tye, N a t u r e , 210, 7 4 2 (1966). J. A u g s t e i n , W. C . A u s t i n , C. A. B a r t r a m a n d R , J. Bosc o t t , J. Med. Chem., 9, 8 1 2 ( 1966) . A. D. L o w r i e a n d A. . R Day, i b i d , 3, 311 (1966). W. E. B a r r e t t , R. L a r k i n a n d L. B e f l o r d , Fed. P r o c . , 25, 258 (1966). T. F. B u r k s a n d J. P. Long, 3 . Pharm. S c i . , 55, 1 4 0 5
Am.
36 37
- Pharmacodynamic Agents
a,
H. P o v a l s k i , A. I. D a n i e l a n d W. D o l a n , Fed. P r o c . , 258 ( 1 9 6 6 ) . R . A. R u t l e d g e , M. P l e s h e r a n d A. J. Plummer, i b i d . , 258 (1966). P. Wolf, C . Wolf, M. M u l l e r a n d G. K e m p t e r , P h a r m a z i e , 3, 474 ( 1 9 6 6 ) . L. De S o l d a t i , I. E. De F o r t e z a , C . R. P e l l e g a t t a a n d H. Cammarota, C a r d i o l o g i a , 4 8. 489 (1966) D. F . H o r r o b i n , L a n c e t , i, 574 (1.966). D , B. Gordon, L a n c e t , i i , 320 (1966). D. J. B r e s l i n , C i r c u l a t i o n , 33, 87 ( 1 9 6 6 ) .
25,
-
59
Chapter 7. Diuretic Agents Edward J. Cragoe, Jr. and John B. Bicking Merck Sharp & Dohme Research Laboratories, West Point, Pa. A l a r g e volume of research p e r t a i n i n g t o d i u r e t i c s was published i n 1966. Many publications were concerned with chemical and patent r e p o r t s which were l a r g e l y extensions of s e r i e s with known d i u r e t i c a c t i v i t y . Others involved b i o l o g i c a l and c l i n i c a l s t u d i e s regarding t h e mode of a c t i o n and e x t r a - r e n a l e f f e c t s of e s t a b l i s h e d d i u r e t i c s . Although novel s t r u c t u r a l types with d i u r e t i c p r o p e r t i e s have been reported and i n t e r e s t i n g fundamental research on e l e c t r o l y t e t r a n s p o r t and mechanism of drug a c t i o n has been described, no obvious breakthrough has occurred during t h i s year.
General. Noteworthy r e o t s l and reviews p e r t a i n i n g t o t h e pharmacologica1,Z endocrinological3 f ; and c l i n i c a l 5 aspects of d i u r e t i c s have appeared i n t h e recent l i t e r a t u r e . The use of d i u r e t i c s i n t h e treatment of hypertension has been reviewed w i t h e s p e c i a l emphasis o t h e hypotens i v e a c t i o n of t h e aldosterone antagonist, spironolactone Fundamental s t u d i e s on t h e mechanism of t r a n s p o r t o f e l e c t r o l y t e across t h e t u b u l a r epithelium have indicated t h a t phospholipids may play a c r i t i c a l r o l e . Phospholipase C and pancreatic l i p a s e markedly reduced t h e r a t e of reabsorption of s a l i n e d r o p l e t s infused i n t o r a t proximal tubules. Likewise, phospholipase C reduced t h e a b i l i t y of e x t r a c t a b l e l i p i d s t o bind sodium and potassium ions i n r a t kidney homogenates; whereas, phospholipase D and ribonuclease appear t o enhance c a t i o n binding.7
,
.2
Organomercurials. Although t h e synthesis of new organomercurial d i u r e t i c s i s apparently a t a s t a n d s t i l l , i n t e r e s t continues i n t h e mode of a c t i o n of agents of t h i s c l a s s . A v a r i e t y of experimental techniques have been used i n attempts t o define more c l e a r l y t h e s i t e of a c t i o n of t h e mercurial d i u r e t i c s i n t h e kidney tubule. Recent s t o p flow s t u d i e s 0 with meralluride have shown that t h e mercurial can i n h i b i t sodium reabsorption i n t h e d i s t a l tubule. The magnitude of t h i s e f f e c t bears a d i r e c t r e l a t i o n s h i p t o plasma sodium concentration. Since furosemide produces an added response during maximal mercurial n a t r i u r e s i s i n normal but not i n a c i d o t i c dogs, it was suggested9 t h a t , i n t h e a c i d o t i c s t a t e , t h e a c t i o n of mercurials i s extended t o t h e ascending l i m b of Henle's loop, considered t o be t h e major s i t e of a c t i o n of furosemide. Studies on t h e d i s t r i b u t i o n of 203Hg-chlormerodrin have already demonstrated that t h e c e l l s of t h e proximal convoluted tubule contain t h e maximal concentration of mercury during d i u r e s i s i n t h e dog. It has now been shown'' t h a t a s i m i l a r d i s t r i b u t i o n of mercury r e s u l t s when d i u r e s i s i s prevented by metabolic a l k a l o s i s o r administration of p-chloromercuribenzoic acid. Therefore, the t u b u l a r binding of chlormerodrin need not be determined s o l e l y by f a c t o r s involved i n t h e production of d i u r e s i s , but
60
Sect. I1 - P h a r m a c o d y n a m i c Agents
A r c h e r , Ed.
may be more c l o s e l y r e l a t e d t o t u b u l a r s e c r e t i o n of t h e drug. The d i s t r i b u t i o n p a t t e r n s of 203Hg-mersalyl have a l s o been d e s c r i b e d . l l Acylphenoxyacetic Acids. Ethacrynic a c i d ( I ) , t h e powerful s a l u r e t i c e f f e c t of which has been documented, was made a v a i l a b l e commercially i n t h e United S t a t e s i n January, 1967. Additional s t u d i e s on t h e s i t e s of a c t i o n of I showed t h a t it probably i n h i b i t s reabsorption of sodium and C H -C-C -0-CH$OOH chloride i n t h e proximal tubule a s well 5 II a s i n t h e ascending l i m b of Henle's CH2 l o 0 p . l ~ 9 ~ 3It was demonstrated i n t h e I perfused dog kidney t h a t I reduces r e n a l vascular r e s i s t a n f t i n c o n t r a s t t o t h e t h i a z i d e s and mercurials which increase r e s i s t a n c e . Ethacrynic a c i d markedly increases bromide excretion and has been recommended f o r t h e therapy of bromide i n t o ~ i c a t i o n . ~ ~
;v
Aromatic Sulfonamides. A considerable volume of b i o l o g i c a l and c l i n i c a l l i t e r a t u r e continues t o appear regarding furosemide (11) which was made a v a i l a b l e t o t h e United S t a t e s ' market i n 1966. I n addition t o
I1
I11
3
t h e publications concerning i t s use i n a v a r i e t y of c l i n i c a l s i t u a t i o n s , some fundamental f a c t s concerning i t s pharmacological p r o p e r t i e s have been elucidated. Stop-flow s t u d i e s i n man have confirmed t h e animal data which indicated t h a t t h e i t e of a c t i o n of t h e drug was t h e loop of Henle and e a r l y d i s t a l tubule.'' Furosemide was reported t o decrease r e n a l vascular r e s i s t a n c e i n t h e kidney of anaesthesized dogs receiving a constant flow of femoral a r t e r y blood. The drug a l s o increased r e n a l blood flow i n animals with i n t a c t kidneys. Hydrochlorothiazide and chlorothiazide showed t h e qpposite e f f e c t s while ethacrynic a c i d was s i m i l a r t o furosemide. These observations o f f e r a hemodynamic b a s i s f o r t h e unique e f f e c t s of furosemide and ethacrynic a c i d s i n c e , i n addition t o t h e i r r e n a l t u u l a r e f f e c t s , they appear t o increase r e n a l blood flow by vasodilation." From toad bladder s t u d i e s , it was concluded t h a t furosemide has no d i r e c t e f f e c t n t h e sodium pump, but may a c t a s an Although t h e e f f e c t i r a t h e r small, antagonist of c y c l i c 3',5'-A".'' furosemide does appear t o reduce blood pressure i n man. 18-20 2 -Chloro -5 -$-methyl-N- ( 2 -methylt etrahydrofurfuryl )sulfamoygbenzene sulfonamide (mefruside, FBA 1500, Bay 1500) (111) was reported t o be a potent d i u r e t i c i n mice, r a t s , dogs and man. The lowest e f f e c t i v e o r a l
-
Diuretics
Chap. 7
C r a g o e and Bicking
61 -
dose i n hydrated r a t s was 0.05 mg./kg. and t h e r e was a l i n e a r increase i n urinary sodium chloride and water as t h e dose was increased t o 320 Maximum s a l u r e s i s considerably above t h a t of t h e t h i a z i d e s was mg./kg. desrribed. Mefruside, i n c o n t r a s t t o hydrochlorothiazide, was e f f e c t i v e i n hepatectomizcd r a t s . It i m abolized t o 2 lactone derivative which 31,@ a l s o has d i u r e t i c properties. E a r l i e r work23 on 3 -sulfamoyl-4-chlorobenzamide, N, ( sulclamide ) has been extended t o include t h e corresponding benzoic acid, V. Both compounds were a c t i v e i n r a t s a t 2 mg./kg. o r a l l y , but a t 50 mg./kg. V is more potent. They were e f f e c t i v i n dogs i n t h e range of 5 t o 30 mg./kg. 26 i.v. and 50 t o 200 mg./kg. p.0.
COR
IV, R V, R
= NH2 =
VII
OH f H 3
V I , R = NHN
9 CH3
A number of hydrazides of 3-sulfamoyl-4-chlorobenzoic acid were studied f o r possible i n t e r a c t i o n s with catecholamine-dependent functions. Only t h e cis-N-( 2,6-dimethyl-l-piperidyl) -3-sulf amoyl-4-chlorobenzamide ( V I , Clopamide, Brinaldix) was active. It i n h i b i t e d reserpine-induced hypothermia i n mice and increased the s e n s i t i v i t y of rabbit a o r t a s t r i p s t o noradrenaline .25
I n a s e r i e s of compounds of t y p e V I I , t h e most a c t i v e i n r a t s were those i n which t h e sulfamoyl group was i n t h e para position and R1, R2 and R3 respectively were (1)H, H, H, ( 2 ) CH3, H, H and ( 3 ) H, CH3, CH3. 26 Benzothiadiazines. A large volume of l i t e r a t u r e continues t o be generated regarding t h e t h i a z i d e s , some of which i s only of a r c h i v a l iazide-induced hyperglycemia has been correlated w i t h potassium va1ueg7J" loss, although more evidence w i l l be required t o v a l i d a t e t h i s finding. Indeed, abnormal glucose tolerance curves r e s u l t i n g from chlorot h i a z i d e therapy are reported t o Le normalized by potassium chloride o r triamterene administration .29 However, t h e hyperglycemia due t o hydrochlorothiazide i n nephrectomized-alloxnized r a t s was r e l a t e d t o increased glycogenolysis caused by i n h i b i t i o n of c y c l i c 3',5'-AMP phosphodiesterase; t h e r e s u l t a n t accumulation of c y c l i c 3 ,5 '-AMP increased the hyperglycemic e f f e c t of epinephrine .30 Other causes of thiazide-induyy3. hyperglycemia have been suggested including reduced i n s u l i n secretion and impaired
62
Sect. I1 - P h a r m a c o d y n a m i c Agents
A r c h e r , Ed.
glucose uptake by peripheral t i s s u e s . 32 Since reports of new t h i a z i d e s which have reached the c l i n i c a r e r a r e i n recent years, a new addition i s worthy of mention. This compound, t h e 3a-methylbenzyl derivative of hydrochlorothiazide ( V I I I ) i s r e f e r r e d t o i n the l i t e r a t u r e a s Diu 60 (Dehydrosanol, Pertensosonol). Preliminary reports on i t s ch m i s t r y have appeared p r e v i 0 u s l y , 3 3 ~ ~ 'but H d e t a i l e d reports of i t s toxlcologica135 and d i u r e t i c properties i n animals a r e now available which indicate that it compares favorably so2 with 0th r t h i a z i d e s i n animals and i n man.3 VIII
,
%
Pteridines. The d i u r e t i c properties of triamterene, 2,4,7-triamino6-phenylpteridine ( I X , R = C g H 5 ) , a r e well known. A number of r e l a t e d compounds ( I X ) i n which t h e -phenyl group was replaced by a v a r i e t y of cycloalkenyl groups and by fury1 were found t o have d i u r e t i c a c t i v i t y i n rats about equal t o t h a t of t r i a ~ n t e r e n e . ~One ~ compound of t h i s group,
Ny2 X
IX
,
2,4,7-triamino-6-(2-furyl)pteridine (furterene, I X , R = 2-furyl) i n the form of i t s formic a c i d s a l t was selected f o r d e t a i l e d study because of i t s low t o x i c i t y . Its action i n promoting sodium and chloride excretion while suppressing potassium excretion resembles t h a t of triamterene. The persistence of a c t i v i t y i n t h e adrenalectomized r a t shows that furterene, l i k e triamterene, d s not function s o l e l y as a s p e c i f i c antagonist of the mineralocorticoids.
3s
Preliminary communications have described the d i u r e t i c a c t i v i t y of t i e 6-pteridinecarboxamide ~y-5256 (X, R1 = C6H5, R2 = R 3 = 2-methoxye t h y l ) . The r e n a l pharmacology of Wy-5256,39 and t h e synthesis and s t r u c t u r e - a c t i v i t y r e l j p i nships of a s e r i e s of 6-pteridinecarboxamides ( X ) including ~y-5256, now have been published i n d e t a i l . Wy-5256 has about the same d i u r e t i c potency a s hydrochlorothiazide i n r a t s and dogs. It probably a c t s d i r e c t l y on the r e n a l tubule t o promote the excretion of nearly equal amounts of sodium and chloride along with some potassium. It i s i n t e r e s t i n g t o note that wy-5256, l i k e furosem iie and i c acid, produces an increase i n t o t a l r e n a l blood flow 42 on t h e pteridinecarboxamides ( X ) have shown t h a t R i must be Studies
ethacTl,
to
Diuretic s
Chap. 7
63 -
C r a g o e and Bicking
a q l , preferably unsubstituted phenyl, f o r good o r a l d i u r e t i c a c t i v i t y . I n a s e r i e s where R2 = R3, maximum a c t i v i t y was reached when these groups a r e 2-methoxyethyl as i n My-5256. In a second series where R2 = H, maxim a c t i v i t y was attained i n compounds i n which R 3 i s 24iethylaminoe t h y l o r 2-morpholinoethyl. Activity w a s l o s t when the 7-amino group was replaced by hydrowl. Pyrazines N-Amidino-3-amino-6-chloropyrazinecarboxamide ( X I )43
.
previously was shown t o reverse the e l e c t r o l y t e excretion e f f e c t s of deoxycorticosterone acetate i n the adrenalectomized r a t and was sho be a potassium-sparing n a t r i u r e t i c agent i n t h e i n t a c t r a t and dog.
I 8to
The preparation and r e n a l e l e c t r o l y t e e f f e c t s of a s e r i e s of compounds i n which the 5-msition of X I ha been v a r i o u s u substituted have been reported.'5 Greatly increased a c t i v i t y was found i n a group of compounds ( X I I ) which bear NH It a 5-amino substituent. The parent compound, C0NH-C -% N-amidino-3,~-diamino-6-chl..oropyrazinecarboxamide (XIIa) i s most a c t i v e , producing a 5C$ reversal of t h e DOCA e f f e c t i n adrenalectomized rats a t m2 2.5 vg./rat. XI produces an equivalent e f f e c t a t 36 pg./rat.
XI, Y = H Compounds of type X I 1 i n which R1 i s H and XII, Y = R ~ ~ N - R2 i s straight chain a l k y l (methyl through XIIa, Y = Nftr butyl), isopropyl, a l l y 1 o r cyclopropyl a r e nearly as potent a s XIIa. Similar compounds i n 2 which R i s branched butyl o r higher a l k y l a r e considerably l e s s active. The 5-dialkylamino compounds with up t o a t o t a l of s i x carbon atoms i n R1 and R2 a r e highly active. The 5-anilino compound ( X I I , R1 = H, R2 = C@5 ) i s moderately active; the homologous benzyl and phenethyl compounds a r e weakly active. H i g h potency i s retained on introduction of a l k y l and
a r y l substituents a t the terminal guanidino nitrogen atoms of XIIa; rephcement of the 6-chlorine atom by hydrogen greatly reduces a c t i v i t y . The introduction of halo, hydroxy, alkoxy, mercapto o r alkylthio groups i n t o the 5-position gives compounds of greatly reduced a c t i v i t y . The action of XIIa i n reversing t h e e l e c t r o l y t e e f f e c t s of aldosterone probably i s d i r e c t l y on t h e d i s t a l tubular handling of sodi potassium rather than through a specific antagonism of the hormone.
k%
C l i n i c a l ~ t u d i e s ' ~ - ~show ' t h a t XIIa-HCl (amiloride hydrochloride) used alone produces a moderate n a t r i u r e s i s and a marked antikaliuresis; it potentiates t h e n a t r i u r e t i c e f f e c t s of hydrochlorothiazide and ethacrynic acid i n edematous and hypertensive p a t i e n t s while completely reversing the k a l i u r e t i c e f f e c t of these diuretics. Other Heterocyclic Compounds. The d i u r e t i c properties of 3,6dicarboxycoumarin and some of i t s e s t e r s have been reported e a r l i e r . 5 1 A new up of coumarincarboxylic acids and t h e i r derivatives have been s t u d i e 3 ' i n the rat and several members show a s i m i l a r pattern of
64
Sect. I1 - P h a r m a c o d y n a m i c Agents
A r c h e r , Ed.
a c t i v i t y , i.e., enhancement of sodium and chloride ion excretion with s l i g h t o r i n s i g n i f i c a n t e f f e c t on potassium excretion. I n a s e r i e s of e s t e r s (XIII) of 3,8-dicarboxycoumarin, t h e 3-ethyl and 3,8-bismethyl e s t e r s were the most active s a l u r e t i c agents (30 mg./kg. o r a l l y ) . A number of lower a l k y l e s t e r s ( X I V ) of 3,6-dicarboxy-4-hydroxycoumarin a l s o were a c t i v e a t t h e same dose and were e f f e c t i v e i n reversing t h e e l e c t r o l y t e e f f e c t s of exogenous aldosterone.
OH XIV
XI11
The c y c l i c immonium s a l t , 1,4-dihydro-2,3-dimethyl-4-phenyl-l,4ethanoisoquinolinium chloride ( X V , Su-14074), i s a d i u r e t i c agent of novel type. It produced a d i u r e t i c , n a t r i u r e t i c and chloruretic ;esponse i n the dog a t 5.0 mg./kg. o r a ~ y . 5 3 Potassium excretion was decreased. Su-14074 had a similar d i u r e t i c and n a t r i u r e t i c e f f e c t i n the r a t a t 6.2 mg./kg. o r a l l y but was without appreciable e f f e c t on potassium e x ~ r e t i o n . 2 ~I n t h e dog, Su-14074 reversed the e l e c t r o l y t e e f f e c t s of i n j e c t e d aldosterone; thus, i t s a c t i o n may be due t o i n h i b i t i o n of the e f f e c t of the endogenous hormone. 53 H
‘SH5
xv
4-Phene t hylamino -lH-pyra z oloLT, 4-gpyrimidine hydrochloride ( XV I ) was reported55 t o have d i u r e t i c and n a t r i u r e t i c a c t i v i t y i n r a t s about equal t o t h a t of acetazolamide; however, it appears t o be longer actring.
XVII
XVIII
‘\
Diuretics
Chap. 7
Cragoe and Bicking
65 -
An investigation of the biological properties of some azoninoindoles, azecinoindoles and benzazecines showed that several of hese bases have 5. The azecinosignificant diuretic and natriuretic activity in rats' indole (XVII) is most active, producing a good diuretic response when given orally at 50 mg./kg.
It has been claimed that 5,5-diphenyl-2-imino-4-oxazolidinone (XVIII) produces a prompt, intense diuresis in the rat when administered orally The volume of urine is increased 5-10 fold; the effect at 20 mg./kg.57 of XVIII on electrolyte excretion was not described.
,
T h e hypoglycemic and lipolysis-inhibi$ing compounds, 3 5-dimethylpyrazole and 3,5-dimethylisoxazole, produce a significant diuresis in fasted rats at 100 and 50 mg./kg. i.p. This effect is gr atly attenuated in water-loaded rats and is not observed in guinea pigs.5g The diuretic activity like the hyyoglycemic activity of these compounds appears to be species-specific.
The azidopyrimidines (XIX), 5-ethowethyl- and 5-propargyl derivatives of 2-amino-4-azido-6-phenylpyrimidine, reverse the oliguria produced by ADH in the alcoholsaline loaded rat59 at doses less than 1 mg./kg. This action is the result of a nonspecific antagonism to the hormone since both compounds produce diuresis and saluresis in the absence of injected ADH. N3 SLudies of the diuretic action of (SC-16102) sc-16102 in the dog also have been XIX, R = C,H5OCH2C%-
-
CH-XCH2
(sc-16100)
reported.60
Hydrazides. A series of hydrazides and sulfiydrazides were tested orally as diuretics in mice at 50 mg./kg. Two compounds, XX and XXI, were as active as ch1orothiazi.de at 5 mg./kg. Three other gpmpounds, XXII, XXIII and propionhydrazide,were somewhat less active. XX, R1 = CH3O; R2,R3 = H XXI, R2 = KO; R1,R3 = H XXII, R1 = HO; R2,R 3 = H XXIII, R1,R2,R3 = HO
Hormonal Factors. A number of publications have centered on the mode of action and the inhibition of the antidiuretic hormone (ADH, vasopressin). It was shown that ADH in the rat may regularly cause diuresis as well as the generally observed antidiuresis.62 This biphasic action is dose-dependent, i.e., small doses of the hormone injected o r infused
66
Sect.
I1 - P h a r m a c o d y n a m i c A g e n t s
A r c h e r , Ed.
produce diuresis; l a r g e r doses produce antidiuresis. An analogous dual action of oxytocin on water excretion was a l s o reported.63 Studies i n human subjects support the previous hypothesis that cyclic adenosine 3',5'-monophosphate i s t h e i n t r a c e l l u l a r mediator of the a n t i d i u r e t i c action of ADH. Given intravenously, the nucleotide decreased urinary volume and raised osmolarity i n normal subjects given an excess water load; i n a patient wit& diabetes insipidus, it produced a response exactly l i k e ADH ( p i t r e s s i n ) , Cyclophosphamide (XXIV) (50 and. 100 mg./kg.) and i t s metabclite 2,2'-dichlorodiethylamine, were found t o produc a water diuresis i n r a t s and dogs.85 Evidence was presented that these compounds a c t by inhibiting the action of ADH. A similar e f f e c t of 5,5-diphenylhydantoin i n man a t the 66 high i.v. dose of 500 mg. was reported. The i n t e r e s t i n g observation t h a t the analgesic acetaminophen (N-acetylXXIV p-aminophenol) accelerates net water flow across the i s o l ted toad bladder A single dose l e d t o i t s t r i a l i n patients w i t h diabetes insipidus.'7 (1.2 t o 2.4 g,) produced a marked f a l l i n urinary excretion and a r i s e i n osmolality. It was suggested t h a t acetaminophen may be a u s e f i l subs t i t u t e f o r vasopressin i n diabetes insipidus. The complex e f f e c t s of aldosterone infusions on t h e r e n a l res t o angiotensin i n normal and edematous subjects have been studied.
BY"
Diuretics from Plant Sources. Reports of d i u r e t i c a c t i v i t y i n naturally-occurring substances o r t h e i r e x t r a c t s have been abundant i n diuretic the past and they a r e aluays d i f f i c u l t t o evaluate. Recent properties have been described f o r e x t r a c t s of birch leavesk$' (Betula verrucosa ) celery7O (Apium aveolens ) and the Indian plants, Boerhaavia repens and Boerhaavia rependa. 5T--
,
LEN3IlCES
B,
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Chap. 7
Diuretics
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a
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Pharmacodynamic Agents
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8 (1966).
C h a p t e r 8. Angina P e c t o r i s and A n t i a n g i n a l Agents Arch C. Sonntag and Robert I. M e l t z e r Warner-Lambert Research I n s t i t u t e , M o r r i s P l a i n s , N . J . I t is g e n e r a l l y a g r e e d t h a t t h e p a i n a s s o c i a t e d w i t h a n g i n a p e c t o r i s i s due t o a r e l a t i v e hypoxia of t h e myocardium. A t t a c k s of a n g i n a can b e p r e c i p i t a t e d by i n c r e a s i n g t h e h e a r t ' s oxygen demand, o r by d e c r e a s i n g i t s s u p p l y . Emotional f a c t o r s p l a y a m a j o r r o l e i n i n c r e a s i n g m y o c a r d i a l oxygen r e q u i r e m e n t s by i n c r e a s i n g c a r d i a c s y m p a t h e t i c n e r v o u s a c t i v i t y .
The h e a r t i s a c u r i o u s o r g a n . I n c o n t r a s t t o s k e l e t a l m u s c l e , myoc a r d i a l metabolism i s e n t i r e l y a e r o b i c , t h e r e b e i n g l i t t l e o r no c o n v e r s i o n of g l u c o s e o r glycogen t o l a c t i c a c i d . I n f a c t , h e a r t m u s c l e e x t r a c t s l a c t i c a c i d from t h e b l o o d , c o n v e r t i n g i t t o p y r u v i c a c i d . 2 P r o d u c t i o n of l a c t i c a c i d by t h e myocardium h a s been o b s e r v e d d u r i n g e x e r c i s e of p a t i e n t s w i t h c o r o n a r y a r t e r y d i s e a s e . L a c t i c a c i d p r o d u c t i o n i s most f r e q u e n t l y o b s e r v e d i n e x t e n s i v e l y d i s e a s e d h e a r t s , and i s u s u a l l y a s s o c i a c t e d w i t h d i s e a s e of t h e l e f t a n t e r i o r d e s c e n d i n g c o r o n a r y a r t e r y . 3 Skele t a l muscle e x t r a c t s about 22 p e r c e n t of t h e a v a i l a b l e b l o o d oxygen, w h i l e e x t r a c t i o n i n t h e h e a r t r u n s a b o u t 7Q%.4 T h i s h i g h a r t e r i o - v e n o u s oxygen d i f f e r e n c e r e q u i r e s t h a t changes i n m y o c a r d i a l oxygen s u p p l y be dependent on m o d i f i c a t i o n s i n c o r o n a r y b l o o d flow (CBF). Drug t h e r a p y of a n g i n a p e c t o r i s h a s t r a d i t i o n a l l y i n v o l v e d t h e u s e of a g e n t s b e l i e v e d t o b e c o r o n a r y v a s o d i l a t o r s i n a n e f f o r t t o i n c r e a s e CBF. Some a g e n t s which produce a marked i n c r e a s e i n CBF i n t h e normal s u b j e c t f a i l t o e f f e c t e i t h e r an i n c r e a s e i n CBF o r r e l i e f of p a i n i n p a t i e n t s w i t h a n g i n a p e c t o r i s . F a i l u r e of p u r p o r t e d c o r o n a r y v a s o d i l a t o r s t o rel i e v e a n g i n a may b e due t o a number of f a c t o r s . The myocardium p o s s e s s e s an extremely e f f i c i e n t auto-regulatory system, t h e s t r o n g e s t s t i m u l u s f o r v a s o d i l a t i o n b e i n g hypoxia. I n o r d e r t o produce a t h e r a p e u t i c d e g r e e of v a s o d i l a t i o n i n t h e d i s e a s e d h e a r t , a drug must produce a g r e a t e r d e g r e e of v a s o d i l a t i o n t h a n t h e hypoxia i t s e l f . G o r l i n h a s concluded t h a t t h e f a i l u r e of v a s o d i l a t o r s t o i n c r e a s e CBF i n a n g i n a l p a t i e n t s m i g h t b e due t o a hypoxia-produced e x h a u s t i o n of t h e c o r o n a r y r e s e r v e f o r f u r t h e r vasod i l a t i o n . 5 ' McGregor and Fam have p o i n t e d o u t t h a t t h i s d o e s n o t e x c l u d e t h e e f f e c t of t h e s e d r u g s on c o l l a t e r a l flow. These a u t h o r s a c c e p t t h e t h e o r y of an a u t o - r e g u l a t o r y mechanism which a d j u s t s b l o o d flow t o metaboli c need. T h i s a d j u s t m e n t depends on t h e p r e s e n c e o f a m e t a b o l i t e i n an a r t e r i o l e i n c l o s e c o n t a c t t o t h e m y o c a r d i a l c e l l . T h i s mechanism regul a t e s t h e flow of b l o o d a t t h e s i t e of oxygen u t i l i z a t i o n and s h o u l d n o t b e disturbed. I n t h e i s c h e m i c h e a r t , t h e f l o w of b l o o d t o t h e a u t o - r e g u l a t e d a r t e r i o l e s i s i n s u f f i c i e n t . The u s e f u l a n t i a n g i n a l a g e n t s h o u l d e x e r t i t s e f f e c t by i n c r e a s i n g t h e b l o o d s u p p l y t o t h e a r t e r i o l e s by a c t i n g on t h e l a r g e c o n d u c t i v e and c o l l a t e r a l v e s s e l s . McGregor and Fam assert t h a t an a g e n t which i n c r e a s e s CBF by i n t e r f e r i n g w i t h t h e a u t o - r e g u l a t o r y f u n c t i o n
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w i l l a l l o w t h o s e a r t e r i o l e s which are a l r e a d y r e c e i v i n g a d e q u a t e blood t o f u r t h e r d i v e r t blood away from ischemic areas and i n t o h e a l t h y o n e s . 6 During t h e l a s t few y e a r s t h e r e h a s been a de-emphasis of t h e anat o m i c a l c o n s i d e r a t i o n s a s s o c i a t e d w i t h a n g i n a p e c t o r i s and an i n c r e a s i n g concern of a p o s s i b l e u p s e t of a u t o - r e g u l a t i o n o r of s y m p a t h e t i c s t i m u l a t i o n i n t h e h e a r t . Berne s u g g e s t e d t h e r o l e of a d e n o s i n e n u c l e o t i d e breakdown p r o d u c t s i n t h e a u t o - r e g u l a t i o n of CBF.7 I n t h e p r e s e n c e of a deaminase i n h i b i t o r , a d e n o s i n e h a s been observed i n t h e p e r f u s a t e of i s o l a t e d c a t and g u i n e a p i g h e a r t s s u b j e c t e d t o a n o x i a . The i n c r e a s e i n CBF d u r i n g graded hypoxia h a s been found t o b e p r o p o r t i o n a l t o t h e sum of adenosine , i n o s i n e , and hypoxanthine r e l e a s e d from myocardial t i s s u e .8 The p o s s i b l e involvement of plasma k i n i n s i n t h e a u t o - r e g u l a t i o n of CBF h a s been s u g g e s t e d . Bradykinin, k a l l i d i n , o r e l e d o i s i n were found t o i n crease coronary s i n u s o u t f l o w , coronary s i n u s oxygen t e n s i o n , and s t r o k e flow w i t h o u t a f f e c t i n g blood p r e s s u r e o r h e a r t r a t e . The e f f e c t s of t h e s e k i n i n s w e r e a t t r i b u t e d t o coronary v a s o d i l a t i o n by a d i r e c t a c t i o n on t h e myocardial v e s s e l s . G o r l i n h a s s u g g e s t e d t h a t plasma k i n i n s , r e l e a s e d from ischemic o r inflamed t i s s u e , may b e p a i n producing s u b s t a n c e s . I t s h o u l d b e p o i n t e d o u t t h a t i t is n o t known whether o r n o t t h e s e a g e n t s a r e r e l e a s e d i n t o t h e c i r c u l a t i o n d u r i n g a t t a c k s of a n g i n a p e c t o r i s . I n t h e c o u r s e of t h e i r work on a c a n i n e h e a r t model f o r a n g i n a , S z e n t i v a n y i and co-workers c l a i m t o have found evidence f o r t h e e x i s t e n c e of a s u b s t a n c e , hyperemin, which r e g u l a t e s coronary v e s s e l r e s p o n s i v e n e s s t o m e t a b o l i c r e q u i r e m e n t s . I n t h e absence of hyperemin, v a s o d i l a t i o n could no l o n g e r be produced by m e t a b o l i c s t i m u l i o r by a d r e n a l i n . Adminis t r a t i o n of hyperemin from a donor h e a r t r e e s t a b l i s h e d normal r e s p o n s e s . l 1 Presumably, a n g i n a p e c t o r i s may i n v o l v e a l a c k o r i n s u f f i c i e n c y of a hyperemin t y p e m a t e r i a l i n t h e human h e a r t . The hemodynamics a s s o c i a t e d w i t h a t t a c k s of a n g i n a p e c t o r i s have been e x t e n s i v e l y s t u d i e d . Diamond r e p o r t e d e l e v a t e d l e f t v e n t r i c u l a r end d i a s t o l i c p r e s s u r e s d u r i n g e x e r t i o n a l angina. Roughgarden n o t i c e d an i n c r e a s e d s y s t e m i c and pulmonary blood p r e s s u r e d u r i n g a t t a c k s of e x e r t i o n a1 and spontaneous G o r l i n and h i s a s s o c i a t e s r e p o r t e d a maxi m a l i n c r e a s e i n l e f t v e n t r i c u l a r end d i a s t o l i c p r e s s u r e of 3mm Hg. d u r i n g e x e r t i o n a l angina and no p r e s s u r e change when a n g i n a followed t h e adminis t r a t i o n of i s o p r o t e r e n 0 1 . l ~ P a r k e r observed s l i g h t i n c r e a s e s i n l e f t v e n t r i c u l a r end d i a s t o l i c p r e s s u r e t o p r e c e d e t h e o n s e t of e x e r t i o n a l ang i n a . However, no c o r r e l a t i o n w a s found between t h e o n s e t of p a i n and t h e development of p r e s s u r e changes. l 6 McGregor’s group found no d i f f e r e n c e i n t h e hemodynamics of a n g i n a l p a t i e n t s from normal s u b j e c t s , even though t h e p a t i e n t s w e r e e x p e r i e n c i n g a n g i n a l p a i n . The r e s p o n s e of b o t h groups t o s u b l i n g u a l a d m i n i s t r a t i o n of n i t r o g l y c e r i n , e i t h e r a t rest o r t e n minRoughgarden m a i n t a i n s t h a t an a n g i n a l utes before exercise , w a s s i m i l a r . a t t a c k i s accompanied by an i n c r e a s e i n p r e s s u r e and t h a t r e l i e f from t h e a t t a c k , whether spontaneous o r as a r e s u l t of n i t r o g l y c e r i n t r e a t m e n t , i s accompanied by a drop i n blood p r e s s u r e towards t h e p r e - a t t a c k l e v e l . l 4 The e v a l u a t i o n of p o s s i b l e a n t i a n g i n a l a g e n t s h a s been l i m i t e d t o
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d e t e r m i n a t i o n of CBF changes. The methodology of s c r e e n i n g a n t i a n g i n a l 1 9 , 2 o Rowe c r i t i c i z e d a v a i l a b l e methods compounds h a s been reviewed. 4 9 of e v a l u a t i o n on t h e b a s i s t h a t t h e y g i v e no i n f o r m a t i o n c o n c e r n i n g t h e d i s t r i b u t i o n of b l o o d flow w i t h i n t h e myocardium o r t h e e f f e c t s on a r t e r i o venous communications. 2o I t is q u i t e l i k e l y t h a t d i f f e r e n c e s i n d i s t r i b u t i o n of CBF r a t h e r t h a n t o t a l flow are i m p o r t a n t .
A major d i f f i c u l t y w i t h t r a n s f e r r i n g r e s u l t s o b tain ed i n t h e laborat o r y t o t h e c l i n i c i s t h e f a c t t h a t t h e s e s t u d i e s are u s u a l l y c a r r i e d o u t i n animals w i t h normal c i r c u l a t i o n , o r o t h e r s i t u a t i o n s which d i f f e r g r e a t l y from t h o s e found i n t h e d i s e a s e d h e a r t . There have been many e f f o r t s t o s c r e e n a n t i a n g i n a l d r u g s u s i n g exp e r i m e n t a l l y induced c o r o n a r y i n s u f f i c i e n c y . S z e n t i v a n y i and Juhasz-Nagy have a t t e m p t e d t o produce an a n i m a l model t o S i m u l a t e a n g i n a p e c t o r i s . A f u n c t i o n a l c o r o n a r y r i g i d i t y r e s e m b l i n g t h a t found i n a n g i n a l s u b j e c t s w a s induced i n t h e dog h e a r t by p r o l o n g e d h y p o x i a , b i l a t e r a l s t e l l e c t o m y , o r by i n t r a c o r o n a r y i n j e c t i o n o f hexamethonium o r dibenamine. These w o r k e r s c l a i m t h a t p a p a v e r i n e and p r e n y l a m i n e ( I ) c a u s e v a s o d i l a t i o n i n t h e s t a t e of f u n c t i o n a l c o r o n a r y r i g i d i t y . I n t r a c o r o n a r y i n j e c t i o n of p a p a v e r i n e produced an i n c r e a s e d flow b u t d i d n o t r e s t o r e t h e hyperemic r e s p o n s e t o b r i e f r e d u c t i o n i n c o r o n a r y flow.21 U n f o r t u n a t e l y , t h e s e a u t h o r s d i d n o t r e p o r t t h e e f f e c t s of n i t r a t e s on t h e i r model. The u s e of p i t u i t r i n i n duced c o r o n a r y v a s o c o n s t r i c t i o n h a s r e c e n t l y been r e i n v e s t i g a t e d by Papp and S z e k e r e s . I n j e c t i o n of p i t u i t r i n produced c o r o n a r y i n s u f f i c i e n c y i n t h e c o n s c i o u s r a b b i t as measured by t h e e l e v a t i o n i n t h e T wave i n t h e ECG. The l o w e s t dosage of drug c a p a b l e of n o r m a l i z i n g t h e T wave a m p l i t u d e i n 50% o f t h e t e s t a n i m a l s , o r t h e p e r c e n t a g e d e c r e a s e i n t h e T wave produced by d i f f e r e n t dosages of t h e d r u g s , w a s c l a i m e d t o b e more s e n s i t i v e f o r drug e v a l u a t i o n t h a n r e s u l t s o b t a i n e d by i n h i b i t i o n o f p i t u i t r i n induced v a s o c o n s t r i c t i o n . 2 2 I n a l l a t t e m p t s t o produce e x p e r i m e n t a l c o r o n a r y ischemia, t h e q u e s t i o n remains as t o how c l o s e l y t h e e x p e r i m e n t a l p r o c e d u r e resembles t h e c l i n i c a l s i t u a t i o n . The c l i n i c a l e v a l u a t i o n of a n t i a n g i n a l d r u g s h a s been r e c e n t l y reviewed.23 Russek h a s c r i t i c i z e d t h e t e c h n i q u e s used i n t h e e v a l u a t i o n of a n t i a n g i n a l d r u g s . The u s e of a d o u b l e b l i n d t e c h n i q u e i s no g u a r a n t e e t h a t t h e r e s u l t s are i n f a l l i b l e . According t o Russek, many of t h e s e s t u d i e s i n v o l v e an e x p e r i m e n t a l d e s i g n i n which t h e drug i s a d m i n i s t e r e d witho u t r e g a r d t o i t s known p h a r m a c o l o g i c a l a c t i o n and no e f f o r t i s made t o s y n c h r o n i z e t h e drug e f f e c t w i t h t h e p e r i o d i c i t y o f a n g i n a l a t t a c k s . 2 4 Wendkos h a s proposed a n " O r t h o s t a t i c E l e c t r o c a r d i o g r a p h i c Index" i n an a t t e m p t t o d e m o n s t r a t e n i t r a t e a ~ t i v i t y . ' ~ T h i s s t u d y i s h a r d l y conc l u s i v e as i t w a s c a r r i e d o u t on f o u r s c h i z o p h r e n i c s w i t h o u t d e m o n s t r a b l e o r g a n i c h e a r t d i s e a s e . Wendkos r e c e n t l y r e p o r t e d t h a t n i t r o g l y c e r i n and i s o s o r b i d e d i n i t r a t e a b o l i s h e d ECG s i g n s o f i s c h e m i a provoked by i . V . adm i n i s t r a t i o n of e r g o t a l k a l o i d s t o a n g i n a l p a t i e n t s . 26 The u s e of ECG changes i n e v a l u a t i n g a n t i a n g i n a l d r u g s h a s been w i d e l y criticized. The ECG g i v e s o n l y i n d i r e c t i n f o r m a t i o n c o n c e r n i n g t h e s t a t e
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Phsrmacodynamic Agents
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and adequacy of t h e coronary c i r c u l a t i o n . Abrahamsen and Y i i l m a i n t a i n t h a t ST changes may n o t r e f l e c t myocardial blood s u p p l y , as d i s t u r b a n c e s i n CBF can be r e v e r s e d w i t h o u t changes i n t h e E C G . 2 7 The l a c k of understanding of a n g i n a p e c t o r i s i s r e f l e c t e d i n t h e wide v a r i e t y of drugs used i n t h e management of t h i s syndrome. I n a r e c e n t review, Master l i s t e d 70 d i f f e r e n t m e d i c a t i o n s i n c l u d i n g n a r c o t i c s , vasod i l a t o r s , t r a n q u i l i z e r s , a n t i s p a s m o t i c s , a n t i c o a g u l a n t s , hypometabolic a g e n t s , e s t r o g e n s , h y p e r c h o l e s t e r o l e m i a a n t a g o n i s t s , MA0 i n h i b i t o r s , and vitamins.23 D e s p i t e c r i t i c i s m of i t s e f f i c a c y and mode of a c t i o n , n i t r o g l y c e r i n remains t h e most widely used drug i n a n g i n a l t h e r a p y . 2 8 y 2 9 There h a s been a growing r e a l i z a t i o n t h a t n i t r o g l y c e r i n may e x e r t i t s t h e r a p e u t i c e f f e c t through a number of mechanisms. I t i s w e l l known t h a t n i t r o g l y c e r i n i n c r e a s e s CBF i n normal i n d i v i d u a l s . Using n i t r o u s o x i d e d e s a t u r a t i o n t e c h n i q u e s t o determine CBF, G o r l i n found s u b l i n g u a l n i t r o g l y c e r i n t o d e c r e a s e CBF by 16% i n p a t i e n t s w i t h a n g i n a p e c t o r i s . G o r l i n s u g g e s t s t h a t t h e b e n e f i c i a l e f f e c t s of n i t r o g l y c e r i n may be t h e r e s u l t of d e c r e a s e d myoc a r d i a l c o n t r a c t i l i t y . 5 The u s e of n i t r o u s o x i d e t e c h n i q u e s h a s been c r i t i c i z e d and t h e y have been r e p l a c e d by methods based on r a d i o a c t i v e i s o t o p e s . 2 0 Binds group, using Rb84 i n a n g i n a l p a t i e n t s , found a 13% d e c r e a s e i n CBF 2-8 minutes a f t e r s u b l i n g u a l n i t r o g l y c e r i n a d m i n i s t r a t i o n , and a 5% d e c r e a s e a f t e r 8-15 m i n u t e s . Bing r e p o r t s s i m i l a r d e c r e a s e s i n CBF f o r i p r o v e r a t r i l (11) and carbochromene (111). 3 0 Measurements of CBF u s i n g Xe133 have shobm n i t r o g l y c e r i n t o have a b i p h a s i c r e s p o n s e . R e e s r e p o r t e d t h a t i n dogs n i t r o g l y c e r i n produced an i n c r e a s e i n l e f t v e n t r i c u l a r e f f i c i e n c y , as w e l l as an immediate r i s e i n CBF which w a s g r e a t e s t a t t h e end of i n j e c t i o n , f e l l away a t 3 minutes and reached a minimum a t 6 m i n u t e s , t h e n r e t u r n e d t o normal. Rees s u g g e s t e d t h a t t h e e f f e c t of n i t r o g l y c e r i n on t h e coronary v e s s e l s i s b r i e f and r e s t r i c t e d t o t h e f i r s t phase. The subsequent i n c r e a s e i n coronary r e s i s t a n c e might t h e n be an a u t o - r e g u l a t o r y e f f e c t due t o reduced myocardial oxygen r e q u i r e m e n t s . 3 1 B e r n s t e i n , using X e l 3 3 t e c h n i q u e s , found i n t r a c o r o n a r y i n j e c t i o n of n i t r o g l y c e r i n t o produce a b i p h a s i c response i n man as w e l l as dogs. I n pat i e n t s w i t h a n g i n a p e c t o r i s , t h e r e w a s a 38.5% i n c r e a s e i n CBF % m i n u t e a f t e r a d m i n i s t r a t i o n of n i t r o g l y c e r i n . A t 4-6 minutes t h e i n c r e a s e i n flow was o n l y 4 . 8 % . This b r i e f i n c r e a s e i n CBF could b r i n g about r e l i e f of p a i n by removal of m e t a b o l i t e s from ischemic areas of t h e myocardium. B e r n s t e i n s u g g e s t s t h a t s y s t e m i c e f f e c t s predominate i n t h e second phase of n i t r o g l y c e r i n r e s p o n s e t o g i v e d e c r e a s e d a r t e r i a l p r e s s u r e , c a r d i a c o u t p u t , and d e c r e a s e d coronary v a s c u l a r r e s i s t a n c e . Because of t h e drop i n a t r i a l p r e s s u r e , coronary flow f a l l s below c o n t r o l l e v e l s . The prophyl a c t i c and s u s t a i n e d a c t i o n s of n i t r o g l y c e r i n could be due t o a lowering of myocardial metabolism. 32 B e r n s t e i n ' s r e s u l t s are open t o c r i t i c i s m because of t h e u s e of i n t r a c o r o n a r y i n j e c t i o n s of r e l a t i v e l y h i g h conc e n t r a t i o n s of n i t r o g l y c e r i n . McGregor's group m a i n t a i n s t h a t r e t r o g r a d e flow i n t o an ischemic area may be i n c r e a s e d f o r twenty m i n u t e s f o l l o w i n g n i t r o g l y c e r i n . The a c t i o n of n i t r o g l y c e r i n would t h e n be due t o a r e d i s t r i b u t i o n of blood w i t h i n t h e
Chap. 8
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myocardium, accompanied by a reduced e n e r g y e x p e n d i t u r e . Najmi found n i t r o g l y c e r i n t o r e d u c e pulmonary a r t e r y p r e s s u r e , t o t a l pulmonary res i s t a n c e and r i g h t v e n t r i c u l a r work. N a j m i s u g g e s t e d t h a t p o o l i n g of b l o o d i n t h e p e r i p h e r a l venous, o r pulmonary v a s c u l a r s y s t e m s , would r e s u l t i n a d e c r e a s e d h e a r t s i z e w i t h concomitant r e d u c t i o n i n c a r d i a c w 0 r k . 3 ~ It seems u n l i k e l y t h a t t h i s r a t i o n a l e a l o n e would e x p l a i n t h e a c t i o n of n i t r o g l y c e r i n , s i n c e v a s o d i l a t i o n and p o o l i n g o f venous b l o o d c o u l d b e accomplished by v a s o d i l a t o r s , which are i n e f f e c t i v e i n r e l i e v i n g a n g i n a l pain. Needleman a t t e m p t e d t o c o r r e l a t e t h e a n t i a n g i n a l a c t i v i t y of n i t r a t e s w i t h t h e i r a b i l i t y t o produce l o s s of r e s p i r a t o r y c o n t r o l i n m i t o c h o n d r i a . H e s u g g e s t s t h a t n i t r o g l y c e r i n e x e r t s i t s e f f e c t by r e a c t i n g w i t h SH g r o u p s w i t h i n t h e m i t o c h o n d r i a , t h e r e b y c a u s i n g an uncoupling o f p h o ~ p h o r y l a t i o n ? ~ Russek h a s found i s o s o r b i d e d i n i t r a t e and p e n t a e r y t h r i t o l t e t r a n i t r a t e t o produce a s i g n i f i c a n t improvement i n e x e r c i s e t o l e r a n c e as w e l l as e x e r c i s e ECG t e s t s . 3 5 A wide v a r i e t y of n i t r a t e esters have been found t o p r o v i d e r e l i e f of a n g i n a p e c t o r i s . There i s no i n f o r m a t i o n , however, t o s u g g e s t a d i f f e r e n c e i n t h e b a s i c p h a r m a c o l o g i c a l a c t i o n o f t h e s e compounds. Such d i f f e r e n c e s are {resumably due to d i f f e r e n c e s i n a b s o r p t i o n and rates of metabolism. 36 9 3 7 , Despite the f a c t t h a t Dipyridamole i s a p o t e n t c o r o n a r y v a s o d i l a t o r . i t c a u s e s a s u b s t a n t i a l i n c r e a s e i n CBF, i t s v a l u e f o r t h e a c u t e r e l i e f o r p r e v e n t i o n of a n g i n a p e c t o r i s h a s been s e r i o u s l y q u e s t i o n e d . Considerable e f f o r t h a s been expended i n t h e s t u d y o f t h i s drug. D e u t l i c k e r e p o r t s d i p y r i d a m o l e t o i n h i b i t a d e n o s i n e deaminase which r e s u l t s i n an accumulat i o n of a d e n o s i n e . S i n c e a d e n o s i n e i s a p o t e n t v a s o d i l a t o r , t h e r e i s an i n c r e a s e i n CBF. 3 9 Emmons found d i p y r i d a m o l e t o i n h i b i t p l a t e l e t a g g l u t i n a t i o n and proposed t h a t d i p y r i d a m o l e p r e v e n t s t h e u p t a k e of a d e n o s i n e by r e d blood c e l l s , thereby delaying its deamination. 4 0 S t a f f o r d f e e l s t h a t d i p y r i d a m o l e i n h i b i t i o n of a d e n o s i n e deaminase i s u n l i k e l y , as h i g h conc e n t r a t i o n s a r e n e c e s s a r y t o produce i n h i b i t i o n o f deaminase from i n t e s t i n a l mucosa. Much lower c o n c e n t r a t i o n s of d i p y r i d a m o l e p o t e n t i a t e t h e a c t i o n of a d e n o s i n e on m y o c a r d i a l t i s s u e . S t a f f o r d proposes t h a t d i p y r i damole p r e v e n t s t h e u p t a k e o f a d e n o s i n e by m y o c a r d i a l t i s s u e o r r e d blood cells. Schmidt r e p o r t e d d i p y r i d a m o l e produces i n c r e a s e d m y o c a r d i a l c o l l a t e r a l c i r c u l a t i o n i n dogs. 4 2 McGregor found d i p y r i d a m o l e t o i n c r e a s e c a r d i a c o u t p u t and v e n t r i c u l a r m i n u t e work as a r e s u l t of i n c r e a s e d s t r o k e volume.43 McGregor m a i n t a i n s t h a t t h e i n c r e a s e d CBF i s a r e s u l t of an i n c r e a s e i n t h e r a t e of c a p i l l a r y f l o w 4 4 r a t h e r t h a n a r e s u l t of s h u n t i n g through o t h e r pathways a s s u g g e s t e d by Winbury. 4 5 Prenylamine ( I ) was i n t r o d u c e d i n Europe as a c o r o n a r y v a s o d i l a t o r which r e d u c e s t h e n o r a d r e n a l i n e and s e r o t o n i n c o n t e n t of t h e h e a r t . Init i a l double b l i n d s t u d i e s have shown a d e c r e a s e i n t h e p a i n of a n g i n a p e c t o r i s . R e s u l t s u s i n g o b j e c t i v e methods, b a s e d on ECG changes and Masters Two-step t e c h n i q u e s , have been e q u i v o c a l . I t o found p r e n y l a m i n e , d i p y r i d a m o l e , and 7-chloroethyltheophylline t o i n c r e a s e d i a s t o l i c p r e s s u r e as w e l l as CBF. I t o states t h a t f a c t o r s o t h e r than i n c r e a s e d d i a s t o l i c
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Sect. I1 - P h a r m a c o d y n a m i c A g e n t s
A r c h e r , Ed.
p r e s s u r e are a s s o c i a t e d w i t h i n c r e a s e d CBF and s u g g e s t e d d i p ridamole d i Jacobsson l a t e s coronary arteries even i n coronary s c l e r o t i c p a t i e n t s found no d i f f e r e n c e between t h e e f f e c t s of o x y e t h y l t h e o p h y l l i n e , prenylamine, o r placebo i n t h e r e l i e f of s u b j e c t i v e o r ECG s i g n s of ischemia.47
.“
1
Prenylamine Elocor Hos t a g i n a n Segontin Synadrin
Iproveratr i l Isoptin I1
I
Carbochromene I nt e n s a i n I11
CH.
Lidoflazine
IV
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A number of compounds have been r e p o r t e d which have coronary d i l a t o r p r o p e r t i e s o r o t h e r a c t i v i t i e s which have culminated i n t h e i r c l i n i c a l t r i a l f o r use i n angina p e c t o r i s . L i d o f l a z i n e (IV) is claimed t o be a s p e c i f i c , long a c t i n g coronary v a s o d i l a t o r . T h i s agent a p p e a r s t o reduce coronary v a s c u l a r r e s i s t a n c e i n dogs and causes an i n c r e a s e i n coronary venous po2. 4 8 A s t u d y of i p r o v e r a t r i l (11) , carbochromene (111) , hexobendine (V) , and dipyridamole i n d i c a t e s t h a t t h e s e long a c t i n g coronary v a s o d i l a t o r s probably do n o t exert t h e i r a c t i o n by an a d r e n e r g i c mechanism. Only i n t h e c a s e of carbochromene w a s t h e arterio-venous oxygen d i f f e r e n c e a f f e c t e d by p r i o r r e s e r p i n i z a t i o n . The d o s e - r e l a t e d a c t i v i t y i n r e s e r p i n i z e d do s s u g g e s t s t h a t t h e primary e f f e c t of carbochromene is n o t a d r e n e r g i c . 8 9 Carbochromene h a s been r e p o r t e d t o i n c r e a s e CBF by prolonging t h e a c t i o n of adenosine on t h e coronary arteries. 30 I p r o v e r a t r i l and carbochromene Iproveratril is have been c l i n i c a l l y a v a i l a b l e i n Europe f o r some t i m e . c u r r e n t l y being i n v e s t i g a t e d i n t h e United States. 50 C l i n i c a l t r i a l s of hexobendine have n o t been r e p o r t e d b u t t h e compound appears t o b e headed f o r the clinic. 51
L
Hexobendine U s t imon V
Ildamen V II
-
Benfurodil VI
Pyridinolcarbamate Anginin VIII
Benfurodil (VI) h a s been claimed t o b e a c a r d i o t o n i c - v a s o d i l a t o r , which h a s c l i n i c a l v a i u e i n a n g i n a p e c t o r i s . However, no d a t a is a v a i l a b l e . 5 2 Ildamen (VII) h a s r e c e n t l y been p l a c e d on t h e European market as an a n t i a n g i n a l agent. Ildamen has a p o s i t i v e i n o t r o p i c a c t i v i t y and app e a r s t o b e a s t i m u l a t o r of b e t a a d r e n e r g i c r e c e p t o r s . 5 3 P y r i d i n o l c a r b a m a t e ( V I I I ) , a bradykinin a n t a g o n i s t , h a s been shown t o be an a n t i a r t e r i o s c l e r o t i c agent i n r a b b i t s , and is claimed t o be b e n e f i c i a l i n
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a n g i n a p e c t o r i s , as w e l l as i n reopening occluded a r t e r i a l segments i n p a t i e n t s s u f f e r i n g from a r t e r i o s c l e r o s i s o b l i t e r a n s . 5 4 , 5 5 A d i r e c t r e l a t i o n s h i p between t h e catecholamines and a n g i n a p e c t o r i s h a s been known f o r some t i m e . Raab proposed t h a t a t t a c k s of angina p e c t o r i s r e s u l t from a c o i n c i d e n c e of two b a s i c f a c t o r s : 1. A p r e d i s p o s i n g element of impaired coronary d i l a t a b i l i t y due t o s c l e r o s i s , and 2 . A c a r d i o t o x i c t r i g g e r i n v o l v i n g a temporary i n f l u x i n t o t h e h e a r t of catecholamines. Raab a l s o s u g g e s t e d t h a t a d i r e c t a c t i o n of catecholamines on t h e coronary v e s s e l may be i n v o l v e d i n t h e g e n e s i s of a r t e r i o s c l e r ~ s i s . ~ ~ I t i s g e n e r a l l y accepted t h a t an o v e r e x c i t a b i l i t y i n t h e s y m p a t h e t i c n e r vous system e x i s t s i n a s u b s t a n t i a l number of i n d i v i d u a l s w i t h angina pectoris. V a l o r i r e c e n t l y r e p o r t e d t h a t u r i n a r y e x c r e t i o n of n o r e p i n e p h r i n e and e p i n e p h r i n e w a s g r e a t l y e x a g g e r a t e d f o l l o w i n g myocardial i n f a r c t i o n . 5 7 Nestel h a s shown t h a t compared w i t h normal men, t h o s e w i t h a n g i n a p e c t o r i s s e c r e t e abnormally l a r g e amounts of n o r e p i n e p h r i n e and s i m i l a r amounts of e p i n e p h r i n e i n response t o e m o t i o n a l stress. 5 8
Epinephrine and n o r e p i n e p h r i n e produce an i n c r e a s e i n coronary blood flow. N e v e r t h e l e s s , t h e s e a g e n t s have a d e l e t e r i o u s e f f e c t on p a t i e n t s w i t h a n g i n a p e c t o r i s because t h e i n c r e a s e d CBF i s i n s u f f i c i e n t t o m e e t an i n c r e a s e d oxygen r e q u i r e m e n t , which i s a r e s u l t of i n c r e a s e d blood press u r e , h e a r t r a t e , and myocardial c o n t r a c t i l e f o r c e . A h l q u i s t h a s a t t e m p t e d t o e x p l a i n t h e a c t i o n s of t h e catecholamines i n terms of two d i f f e r e n t t y p e s of a d r e n e r g i c r e c e p t o r s . 5 9 According t o A h l q u i s t ' s nomenclature, a l p h a r e c e p t o r s g e n e r a l l y m e d i a t e v a s o c o n s t r i c t i o n and e x c i t a t o r y f u n c t i o n s , w h i l e s t i m u l a t i o n o f t h e b e t a r e c e p t o r s produces v a s o d i l a t i o n and o t h e r r e s p o n s e s a s s o c i a t e d w i t h smooth muscle relaxation!' Beta r e c e p t o r s are b e l i e v e d t o m e d i a t e t h e c h r o n o t r o p i c and i n o t r o p i c a c t i o n of catecholamines. Epinephrine i s a c t i v e on b o t h a l p h a and b e t a r e c e p t o r s w h i l e t h e a c t i o n of n o r e p i n e p h r i n e i s p r i m a r i l y on t h e a l p h a s i t e s . I s o p r o t e r e n o l h a s l i t t l e a c t i o n on a l p h a s i t e s , b e i n g a p o t e n t s t i m u l a t o r of b e t a r e c e p t o r s . There h a s b r e n a g r e a t d e a l of i n t e r e s t i n t h e n a t u r e of coronary sympathetic stimulation. Braunwald's group observed coronary v a s o d i l a t i o n a f t e r t h e i n t r a c o r o n a r y i n j e c t i o n of i s o p r o t e r e n o l and concluded t h a t b e t a r e c e p t o r s a r e p r e s e n t i n t h e coronary c i r c u l a t i o n . 6 1 Gilmore has r e c e n t l y r e p o r t e d t h e r e s e n c e of both a l p h a and b e t a r e c e p t o r s w i t h i n t h e coronary v a s c u l a t u r e . 6 y Govier found b o t h a l p h a and b e t a r e c e p t o r s as evidenced by changes i n a t r i a l r e f r a c t o r y p e r i o d . 6 3 Gaal and h i s a s s o c i a t e s have s u g g e s t e d t h a t b o t h a l p h a and b e t a r e c e p t o r s are p r e s e n t i n t h e coronary v e s s e l s and t h a t normally t h e b e t a response predominates. A f t e r blockade of t h e b e t a r e c e p t o r s , a d m i n i s t r a t i o n of e p i n e p h r i n e o r n o r e p i n e p h r i n e r e s u l t s i n s t i m u l a t i o n of o n l y a l p h a r e c e p t o r s which r e s u l t s i n coronary v a s o c o n s t r i c t i o n . 64 Zuberbuhler and Bohr s t u d i e d t h e r e s p o n s e of smooth muscle from v a r i o u s s i z e d coronary a r t e r i e s and concluded t h a t a l p h a and b e t a r e c e p t o r s a r e p r e s e n t i n t h e l a r g e r a r t e r i e s , b u t t h a t b e t a recept o r s predominate i n t h e s m a l l e r v e s s e l s . 6 5 Takenaka h a s observed s i m i l a r e f f e c t s i n t h e i s o l a t e d p e r f u s e d dog h e a r t . 66 Braunwald proposed t h a t
Antianginal
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b o t h a l p h a and b e t a r e c e p t o r s are p r e s e n t i n t h e c o r o n a r y a r t e r i e s b u t o n l y b e t a r e c e p t o r s are found i n t h e myocardium.67 By e l e c t r i c a l s t i m u l a t i o n of t h e s t e l l a t e and c a u d a l c e r v i c a l g a n g l i a , S z e n t i v a n y i o b s e r v e d s i m u l t a n e o u s d i l a t i o n i n one r e g i o n of t h e myocardium with c o n s t r i c t i o n i n another. S z e n t i v a n y i concluded t h a t t h e myocardium and c o r o n a r y a r t e r i e s are s u p p l i e d by d i f f e r e n t s y m p a t h e t i c pathways. 68 I t h a s been s u g g e s t e d t h a t t h e v a s o d i l a t i o n o b s e r v e d on s t i m u l a t i o n o f sympathetic f i b e r s i s a r e s u l t of a sympathetic cholinergic i n n e r ~ a t i o n . " ~ I n a r e c e n t s t u d y , F e i g l s t i m u l a t e d t h e s t e l l a t e g a n g l i o n and hypothalamus and found no e v i d e n c e of c h o l i n e r g i c m e d i a t e d c o r o n a r y v a s o d i l a t i o n . 70 I n f o r m a t i o n o b t a i n e d by s y m p a t h e t i c s t i m u l a t i o n of t h e c o r o n a r y c i r c u l a t i o n h a s been r e c e n t l y c r i t i c i z e d . The d i s t r i b u t i o n of a l p h a and b e t a rec e p t o r s w i t h i n t h e c o r o n a r y v a s c u l a t u r e may v a r y w i t h s p e c i e s and physiol o g i c a l s t a t e o f t h e animal. D i f f e r e n t e x p e r i m e n t a l a p p r o a c h e s may f a v o r s t i m u l a t i o n of e i t h e r a l p h a o r b e t a r e c e p t o r s . O t h e r f a c t o r s may b e i n volved such as d o s e o r t i m e dependent a c t i o m o f c a t e c h o l a m i n e s on d i f ferent receptors. 7 1 Because of t h e i r p o s s i b l e r o l e i n a n g i n a p e c t o r i s , t h e c h r o n o t r o p i c , i n o t r o p i c , and oxygen w a s t i n g e f f e c t s of t h e c a t e c h o l a m i n e s have been g r e a t l y e x p l o r e d . Braunwald m a i n t a i n s t h a t t h e d e c r e a s e d e f f i c i e n c y i n m y o c a r d i a l oxygen u t i l i z a t i o n produced by c a t e c h o l a m i n e s i s a consequence of i n c r e a s e d m y o c a r d i a l t e n s i o n . 67 However, t h e c o n s e n s u s of o p i n i o n seems t o b e t h a t t h e s e e f f e c t s a r e due t o changes i n m y o c a r d i a l metabolism i n v o l v i n g s t i m u l a t i o n of t h e b e t a r e c e p t o r s . 72 I n t e r a c t i o n w i t h t h e b e t a r e c e p t o r i s b e l i e v e d t o r e s u l t i n t h e f o r m a t i o n of a d e n y l c y c l a s e which Cyclic c a t a l y z e s t h e f o r m a t i o n of 3 ' , 5 ' - c y c l i c a d e n o s i n e monophosphate. 3 ' , 5'-AMP a c t s as a s e c o n d a r y m e d i a t o r by i n c r e a s i n g g l y c o l y s i s and l y p o l y s i s a s w e l l as i n c r e a s i n g c a r d i a c c o n t r a c t i l i t y . 7 3 , 74,7 5 Svedmyr r e c e n t l y d e m o n s t r a t e d t h a t b l o c k a d e of b e t a r e c e p t o r s w i t h MJ-1999 p r e v e n t s t h e m y o c a r d i a l s t i m u l a t i o n , h y p e r g l y c e m i c , and f r e e f a t t y a c i d and l a c t a t e m o b i l i z i n g e f f e c t s of c a t e c h o l a m i n e s . 7 6 I n view of t h e known a c t i o n s of c a t e c h o l a m i n e s on t h e myocardium and from t h e o b s e r v a t i o n t h a t t h e i n d i v i d u a l w i t h a n g i n a p e c t o r i s h a s a hyp e r a c t i v e s y m p a t h e t i c s y s t e m , i t i s r a t i o n a l i z e d t h a t b l o c k a d e of t h e b e t a a d r e n e r g i c r e c e p t o r s may b e n e f i t t h e a n g i n a l p a t i e n t . There are a number of a g e n t s which produce a s e l e c t i v e b l o c k a d e of t h e b e t a a d r e n e r g i c recept o r , t h e i r s t r u c t u r e a c t i v i t y r e l a t i o n s h i p s have been reviewed. 77 9 7 8 ,79 I n general, beta adrenergic b l o c k i n g a g e n t s a r e e t h a n o l amine A ',R2 derivatives. Dichloroisoproterenol (R1 = 3 , 4 - d i c h l o r o p h e n y l , R 2 = i s o p r o p y l , R3=H) , w a s t h e f i r s t a g e n t t o d i s p l a y s e l e c t i v e b e t a b l o c k i n g a c t i v i t y . However, i t a l s o p o s s e s s e s an i n t r i n s i c b e t a s t i m u l a t o r y a c t i o n . Pronetha l o l , ( R i = l - n a p h t h y l , R 2 = i s o p r o p y l , R3=H) w a s found t o have a b e n e f i c i a l e f f e c t i n a n g i n a l a t i e n t s by b e t a b l o c k a d e which reduced m y o c a r d i a l oxygen r e q u i r e m e n t s . 8g P r o n e t h a l o l h a s some s t i m u l a t o r y a c t i o n on t h e b e t a r e c e p t o r and was withdrawn when i t was found t o produce thymic lymphosarOH R1- C-CH,-N
/R3
78
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coma i n m i c e . 8 1 A l a r g e number of phenethanol amine d e r i v a t i v e s b l o c k the b e t a receptor. INPEA (RI=p-nitrophenyl, R 2 = i s o p r o p y l , R3=H) s e l e c t i v e l y b l o c k s b e t a s i t e s w i t h o u t i n f l u e n c i n g a l p h a r e c e p t o r s . 82 Dimethylisopropylmethoxamine (R1=2,4-dimethylphenyl , Rz=isopropyl, R3=CH3) 8 3 and t-butylmethoxamine, (R1=2 ,4-dimethoxyphenyl, Rz=L-bu t y l , R3=CH3) 84 have been r e p o r t e d t o produce a s e l e c t i v e blockade of some, b u t n o t a l l , b e t a r e c e p t o r s . MJ-1999 (R1=p-methanesulfonamidophenyl, R2=isopropyl, R3=H) h a s been r e p o r t e d t o b e a s e l e c t i v e b l o c k e r of b e t a r e c e p t o r s . 7 6 P r o p r a n o l o l (Ri=l-naphthyloxy , R2=isopropyl , R3=H) h a s e l i c i t e d a g r e a t d e a l of a t t e n t i o n i n t h e t r e a t m e n t of a n g i n a p e ~ t o r i s . Harris ~ ~ rep o r t e d t h a t p r o p r a n o l o l produced a d e c r e a s e i n h e a r t r a t e , c a r d i a c outp u t , s t r o k e volume, e j e c t i o n t i m e i n d e x , and s i g n i f i c a n t i n c r e a s e s i n a t r i a l and mean r i g h t a t r i a l p r e s s u r e s . P r o p r a n o l o l b l o c k s t h e e f f e c t s of i s o p r o t e r e n o l and c a u s e s e p i n e p h r i n e r e v e r s a l . 8 6 The r e v e r s a l of e p i n e p h r i n e as w e l l as i n c r e a s e s i n a t r i a l p r e s s u r e s i s probably due t o an unmasking of t h e less S i g n i f i c a n t s t i m u l a t o r y e f f e c t of t h e a l p h a rec e p t o r s . Working w i t h dogs , Rowels group found p r o p r a n o l o l t o d e c r e a s e body oxygen consumption, c a r d i a c o u t p u t , CBF, and l e f t and r i g h t v e n t r i c u l a r work. T o t a l p e r i p h e r a l , pulmonary and coronary v a s c u l a r r e s i s t a n c e s w e r e i n c r e a s e d . 87 Nayler r e c e n t l y r e p o r t e d t h a t i n t h e a n e s t h e s i z e d dog, p r o p r a n o l o l produced a 29% d e c r e a s e i n CBF as w e l l as a d e c r e a s e i n myoc a r d i a l oxygen consumption. 88 Sowton and Hamer, i n a n g i n a l p a t i e n t s , found t h a t p r o p r a n o l o l reduced c a r d i a c o u t p u t 20% b o t h a t rest and on exercise. S t r o k e volume w a s reduced 15% a t rest and 5% d u r i n g e x e r c i s e . Heart r a t e f e l l 10% a t rest and 15% d u r i n g e x e r c i s e . L e f t v e n t r i c u l a r These changes were work w a s reduced by 21% a t rest and 24% on e x e r c i s e . accompanied by s i g n i f i c a n t d e c r e a s e s i n oxygen uptake. 8 9 Chamberlain found p r o p r a n o l o l i n c r e a s e d h e a r t s i z e a t rest and d u r i n g exercise i n normal subjects. I n double b l i n d s t u d i e s , G o r l i n ' s group found an 81% improvement i n a n g i n a l p a t i e n t s when t r e a t e d w i t h p r o p r a n o l o l . P r o p r a n o l o l produced a d e c r e a s e i n h e a r t r a t e , end d i a s t o l i c v e n t r i c u l a r volume and a f a l l i n l e f t v e n t r i c u l a r s y s t o l i c mean p r e s s u r e . Mechanical e f f i c i e n c y w a s n o t changed by p r o p r a n o l o l b u t oxygen consumption d e c r e a s e d 25%. G o r l i n n o t e s t h a t CBF d e c r e a s e s more t h a n oxygen consumption s u g g e s t i n some coronary Ginn and v a s o c o n s t r i c t i o n , probably a r e s u l t of a l p h a s t i m u l a t i o n . Orgain, i n a double b l i n d s t u d y of 18 p a t i e n t s , found an 83% improvement i n a n g i n a l p a i n frequency. 9 2 H a m e r found p r o p r a n o l o l t o i n c r e a s e exerc i s e t o l e r a n c e i n a n g i n a l s u b j e c t s and s u g g e s t e d t h a t t h i s i s o b t a i n e d a t t h e expense of a r e d u c t i o n i n myocardial c o n t r a c t i l i t y and i n p e r i p h e r a l blood f l o w . 9 3 Rabkin h a s found improvement i n a n g i n a l p a t i e n t s and suggest e d t h e r e i s a c a r r y o v e r e f f e c t a f t e r d i s c o n t i n u i n g t h e d r u g . 9 4 Rabkin's o b s e r v a t i o n i s i n t e r e s t i n g as p r o p r a n o l o l i s known t o have a r e l a t i v e l y s h o r t h a l f - l i f e . 81 E x e r c i s e t o l e r e n c e has been s i g n i f i c a n t l y i n c r e a s e d by a combination of p r o p r a n o l o l and n i t r o g l y c e r i n , s u g g e s t i n g a p o s s i b l e s y n e r g i s t i c e f f e c t . 9 5 Russek r e c e n t l y r e p o r t e d t h a t a combination t h e r a p y of pro-
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p r a n o l o l and n i t r o g l y c e r i n r e s u l t e d i n improvement i n t h e frequency of a n g i n a l a t t a c k s and ECG s i g n s of ischemia. Russek m a i n t a i n s t h a t n i t r o g l y c e r i n compensates f o r t h e v a s o c o n s t r i c t i o n a c t i o n of p r o p r a n o l o l . 9 6 While many i n v e s t i g a t o r s have shown p r o p r a n o l o l t o produce an improvement i n exercise t o l e r a n c e o r consumption of n i t r o g l y c e r i n t a b l e t s , t h e r e i s no work demonstrating improvement i n ECG s i g n s of ischemia. G i l l a m and P r i c h a r d s t u d i e d ECG s i g n s d u r i n g e x e r t i o n a l a n g i n a of 7 p a t i e n t s t r e a t e d with propranolol. Four p a t i e n t s showed a g r e a t e r d e g r e e of ST d e p r e s s i o n w h i l e 3 p a t i e n t s showed l e s s . 9 7 F i s c h h a s c r i t i c i z e d t h e use of b e t a adrenergic blocking agents i n angina p e c t o r i s s i n c e these agents should produce an i n v i v o coronary v a s o c o n s t r i c t i o n , an e f f e c t which i s i n c o n t r a d i c t i o n t o t h e customary use of v a s o d i l a t o r s i n a n g i n a . 9 8 I t i s of i n t e r e s t t h a t b e t a a d r e n e r g i c blockade h a s n o t proved e f f e c t i v e i n prev e n t i n g a t t a c k s of a n g i n a of an emotional o r i g i n . " Snow r e p o r t e d a d e c r e a s e d m o r t a l i t y r a t e f o l l o w i n m y o c a r d i a l i n The i n c r e a s e d f a r c t i o n when p a t i e n t s were t r e a t e d w i t h p r o p r a n o l o l . s u r v i v a l r a t e f o l l o w i n g i n f a r c t i o n w a s a t t r i b u t e d t o a p r e v e n t i o n of c a r d i a l a r r h y t h m i a s by b e t a a d r e n e r g i c blockade. 3 O2 7 More r e c e n t , c a r e f u l l y c o n t r o l l e d , double b l i n d s t u d i e s have f a i l e d t o confirm Snow's a s ' been pointed out t h a t b e t a f i n d i n g s of i n c r e a s e d s u r ~ i v a l . ~ ~ I~t ,h ~ ~ b l o c k i n g a g e n t s s h o u l d b e r e s t r i c t e d t o p a t i e n t s w i t h o u t o v e r t s i g n s of myocardial decompensation. Blockade of t h e s y m p a t h e t i c nervous system i n an i m a i r e d h e a r t removes t h e d r i v e n e c e s s a r y t o m a i n t a i n c a r d i a c funct i o n . PO6
'''
'
The p o s s i b i l i t y of t r e a t i n g a n g i n a p e c t o r i s w i t h b e t a a d r e n e r g i c b l o c k i n g a g e n t s h a s opened new avenues of r e s e a r c h , p a r t i c u l a r l y i n t h e area of c a r d i o v a s c u l a r s y m p a t h e t i c i n n e r v a t i o n . The f u t u r e r o l e of t h e s e a g e n t s i n t h e t h e r a p y of t h e a n g i n a l syndrome i s a q u e s t i o n which i s y e t I t i s hoped t h a t m i s t a k e s made i n p a s t i n v e s t i g a t o be f u l l y answered. t i o n s of a n t i a n g i n a l agents w i l l n o t be repeated i n t h i s area.
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Pharmacodynamic Agents
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A. S t a f f o r d , B r i t . J . Pharmacol. Chemotherap. 2 8 , 218, 1966. H. D. S c h m i d t , J. S c h m i e r , A r z n e i m i t t e l - F o r s c h . 1 6 , 1 0 5 8 , 1966. G . A. B o u s v a r o s , J . E. Campbell, M. McGregor, B r i t . Heart J. 2 8 , 331, 1966. W. H . P a l m e r , W. M. Fam, M. McGregor, Can. J . P h y s i o l . Pharmacol. 4 4 , 777, 1966. " I n t e r n a t i o n a l Symposium on Methods i n Drug E v a l u a t i o n , M i l a n , I t a l y , S e p t . 20-23, 1965" i n Problems i n L a b o r a t o r y E v a l u a t i o n o f A n t i a n g i n a l A g e n t s , M. M. Winbury, Ed North-Holland P u b l i s h i n g Co. Amsterdam, 1967. Y. I t o , Y . Kojima, Y . Hasejawa, S . Sasamoto, T . K i s h i i , T . Kobayoshi, J a p a n e s e Heart J . 7 , 5 2 4 , 1966. K. A. J a c o b s s o n , G. Koch, M. Levander-Lindgren, G . M i c h a e l s s o n , Acta Medica Scand. 1 8 0 , 1 2 9 , 1966. W. K. A. S c h a p e r , R. Xhonneux, A. H. M. J a g e n e a u , P . A . J. J a n s s e n , .I.Pharmacol. E x p t l . Therap. 1 5 2 , 265, 1966. 0. Kraupp, E. Wolner, J . Suko, .Arch. Pharmakol. E x p t l . P a t h o l . 254, 431, 1966. M. Neumann, A. A. L u i s a d a , Am. J. Med. S c i . 251, 86/552, 1966. 0. Kraupp, E . Wolner, L. A d l e r - K a s t n e r , B. P l o s z c z a n s k i , E. T u i s l , A r z n e i m i t t e l - F o r s c h . 1 5 , 1 1 8 7 , 1965. J . S c h m i t t , M. S u q u e t , J . S a l l e , P . Comroy, G . C a l l e t , J . Le-Meur, Chim. Therap. 305, 1966. K. Thiemer, R. S t a d l e u , A r z n e i m i t t e l - F o r s c h . 1 6 , 1 5 0 2 , 1966. T . Shimamoto, H . Maezawa, H. Yamazaki, T . A t s u m i , T . F u g i t a , T . 1 - s h i o k a , T. Sunaga, Am. Heart J . 7 1 , 297, 1966. T. Shimamoto, F. Numanco, T . F u g i t a , Am. Heart J. 71, 216, 1966. W. Raab, Am. J. C a r d i o l . 9 , 5 7 6 , 1962. C. V a l o r i , M. Thomas, L a n c e t 1, 1 2 7 , 1967. P. J. Nestel, A. V e r g h e s e , R. R. H . L o v a l l , Am. H e a r t J. 73, 227, 1966. R. P. A h l q u i s t , Am. J . P h y s i o l . 1 5 3 , 586, 1948. K. P. A h l q u i s t , J. Pharm. S c i . 5 5 , 359, 1966. F. J. K l o c k e , G . A. Kaiser, J . ROSS, J r . , E. Braunwald, C i r c u l a t i o n R e s . 1 6 , 376, 1965. J . P. G i l m o r e , 3 9 t h S c i e n t i f i c S e s s i o n o f The American Heart A s s o c i a t i o n , New York, O c t o b e r 21-23, 1966. W. C. G o v i e r , N . C. Mosal, P. W h i t t i n g t o n , A. H . Broom, J . Pharmacol. E x p t l . Therap. 1 5 4 , 255, 1966. 1'. G. Gaal, A. A. K a t t u s , A. K o l i n , G . R o s s , B r i t . J . Pharmacol. 2 6 , 713, 1966. R. C. Z u b e r b u h l e r , D. F. Bohr, C i r c u l a t i o n R e s . 1 6 , 431, 1965. F. Takenaka, Arch. E x p t l . P a t h o l . Pharmakol. 252, 407, 1966. E. Braunwald, 3 9 t h S e s s i o n of The American Heart A s s o c i a t i o n , New York, O c t o b e r 21-23, 1966. M. S z e n t i v a n y i , J . Pace, W. C. R o n d a l l , Fed. P r o c . 25, 401, 1966. B. Unvas, P h y s i o l . Rev. 4 0 , 1131, 1960. E . 0. F e i g l , C i r c u l a t i o n R e s . 2 0 , 262, 1967. .J. R. P a r r a t t , Am. Heart J . 7 3 , 1 3 7 , 1967. G . H. Acheson, Ed., Second Symposium on C a t e c h o l a m i n e s , M i l a n o , .July 4-9, 1 9 6 5 , Pharmacol. Rev. 1 8 , 1 4 5 , 1966.
82 73. 74. 75. 76.
77. 78. 79. 80.
81.
82. 83. 84. 85. 86. 87.
88. 89. 90. 91. 92. 93. 94. 95. 96. 97. 98. 99. 100. 101. 102. 103. 104. 105. 106.
Sect. I1
- Pharmacodynamic
Agents
A r c h e r , Ed.
R. A. L e v i n e , J. A. Vogel, J. Pharmacol. E x p t l . Therap. 1 5 1 , 262,1966. C. J. E s t l e r , H. P. T. Ammon, Biochem. Pharmacol. 1 5 , 2031, 1966. T. J. Regan, C. B. Moschos, P. H. Lehan, H. A. O l d e w u r t e l , H. K. H e l l e m s , C i r c u l a t i o n R e s . 1 9 , 307, 1966. N. Svedmar, L. Lundholm, L i f e S c i . 6 , 2 1 , 1967. J . H. B i e l , B. K. B. Lum, "The Beta-Adrenergic Blocking Agents", P r o g r e s s I n Drug Research 1 0 , 46, 1966, E. T u c k e r , Ed., B i r k h a u s e r Verleg Basel. J . V. Levy, V. R i c h a r d s , Proc. SOC. E x p t l . B i o l . Med. 1 2 2 , 373, 1966. P. Somani, R. T. Bachand, W. Murmann, L. Almivante, J. Med. Chem. 9 , 823, 1966. G . A. P. A l l e y n e , C. J. D i c k i n s o n , A. C. D o r n h o r s t , R. M. F u l t o n , K. G . Green, I. D. H i l l , P. H u r s t , D. R. L a u r e n c e , T . P i l k i n g t o n , B . N . C. P r i c h a r d , B . Robinson, M. L. Rosenheim, 1226, 1963. J. W. B l a c k , W. A. M. Duncan, R. G. Shanks, B r i t - J . - P h a & a c o l . 25, 577, 1965. W. Murmann, A. Gramma, B u l l . Chim. Farm. 1 0 5 , 203, 1966. B. Levey, J . Pharmacol. E x p t l . Therap. 1 5 1 , 413, 1966. B . Levey, B r i t . J. Pharm. Chemother. 2 7 , 277, 1966. E. Braunwald, Symposium on A d r e n e r g i c R e c e p t o r Blockade, E . Braunwald, Ed., Am. J. C a r d i o l . 18, 303, 1966. W. S. H a r r i s , C. D. S c h o e n f e l d , R. H. Brooks, A. M. W e i s s l e r , & J. C a r d i o l . 1 7 , 484, 1966. D. H. McKenna, R. J . C o r l i s s , S. S i a l e r , W. C. Z a r n s t o r f f , C. W . Crumpton, G . G. Rowe, C i r c u l a t i o n R e s . 1 9 , 520, 1966. W. G. N a y l e r , I. M c l n n i s , J . B. Swann, V. Carson, T. E. Lowe, Heart J. 73, 207, 1967. E. Sowton, J. H a m e r , Am. J . C a r d i o l . 1 8 , 317, 1966. D. A. Chamberlain, Am. J . C a r d i o l . 1 8 , 321, 1966. S. Wolfson, R. A . H e i n l e , M. J. Herman, H. G . Kemp, J . M. S u l l i v a n , R. G o r l i n , Am. J . C a r d i o l . 18, 345, 1966. W. J . Ginn. E. S. O r g a i n , J . Am. Med. Assoc. 1 9 8 , 1214, 1966. J . H a m e r , T. G r a n d j e a n , L. Melendez, G . E. Sowton, B r i t . Heart J . 28, 414, 1966. R. Rabkin, D. P. S t a b l e s , N. W. L e v i n , M. M. Suzman, Am. J . C a r d i o l . 1 8 , 370, 1966. E. Braunwald, Am. J. C a r d i o l . 1 8 , 359, 1966. H. I. Russek, S c i e n t i f i c S e s s i o n s , American C o l l e g e of C a r d i o l o g y , Washington, Feb. 1 6 , 1967. P. M. C. G i l l a m , B. N. C. P r i c h a r d , Am. J . C a r d i o l . 1 8 , 366, 1966. S. F i s c h , Am. Heart J . 72, 1 3 1 , 1966. A. C. D o r n h o r s t , Pharmacol. Rev. 18, 701, 1966. P. J. D. Snow, Am. J . C a r d i o l . 1 8 , 458, 1966. A. Wennevold, E. Sandoe, Acta Med. Scand. 1 8 0 , 715, 1966. A . H a r r i s , Am. J. C a r d i o l . 18, 431, 1966. R. J. Kernohan, B r i t . Heart J . 2 8 , 5 7 7 , 1966. R. Bacon, D. E. J e w i t t , J. P. H. D a v i e s , S. O r a m , L a n c e t 2 , 917, 1966. J . C l a u s e n , N . F e l s b y , F. Schonau-Jorgenson, B. L. N i e l s e n , B. S t r a n g e , L a n c e t 2 , 920, 1966. B r i t . Med. J . , 1311, 1966.
Chapter 9 . Pulmonary and A n t i a l l e r g y Agents. Walter T . Moreland, Chas. P f i z e r & Co., I n c . , Groton, C o n n e c t i c u t . The y e a r ’ s most s i g n i f i c a n t developments i n t h e f i e l d s c o n s i d e r e d t o be w i t h i n t h e scope of t h i s c h a p t e r 1 o c c u r r e d i n areas a s s o c i a t e d w i t h For t h e most p a r t , t h e s e appeared as chronic o b s t r u c t i v e lung disease. r e p o r t s summarizing and c l a r i f y i n g o l d e r thinking; r e g a r d i n g c a u s e and e f f e c t r e l a t i o n s h i p s , o r as s t u d i e s which s u g g e s t new approaches t o be explored. Most of t h e r e p o r t e d drug developments can b e i d e n t i f i e d as a r i s i n g i n a f a i r l y s t r a i g h t f o r w a r d manner from e a r l i e r work.
ObstructA. Lung Disease.--Carabasi2 b r i e f l y summarizea some import a n t d i f f e r e n c e s between b r o n c h i a l asthma, c h r o n i c b r o n c h i t i s , and pulmonary emphysema, which are t h e p r e s e n t l y recognized major c a t e g o r i e s of c h r o n i c o b s t r u c t i v e l u n g d i s e a s e . d h i l e i t is obvious t h a t t h e s e d i s e a s e s have many common f e a t u r e s and t h a t methods of t r e a t m e n t w i l l c o n t i n u e t o o v e r l a p s u b s t a n t i a l l y , such d i s t i n c t i o n s a r e of g r e a t v a l u e because t h e y are an e s s e n t i a l f i r s t s t e p i n i d e n t i f y i n g new approaches t h a t can be l o g i c a l l y pursued w i t h s p e c i f i c methodology. Thus, b r o n c h i a l asthma is viewed as an a l l e r g i c phenomenon a s s o c i a t e d w i t h b r o n c h i a l and t r a c h e a l h y p e r s e n s i t i v i t y t o c h a l l e n g e from a v a r i e t y of s t i m u l i 2 - 4 --a view t h a t is c o n s i s t e n t w i t h t h e f a c t t h a t c o r t i c o s t e r o i a s c o n t i n u e t o occupy a predominant p o s i t i o n i n i t s t r e a t m e n t . 5 ~ 6 I t f o l l o w s t h a t t h e emergence of s i g n i f i c a n t improvements i n t h e primary t r e a t m e n t of bronc h i a l asthma s h o u l d c o n t i n u e t o depend on t h e r e a l i z a t i o n of a c l e a r e r understanding of a l l e r g y . Chronic b r o n c h i t i s , on t h e o t h e r hand, i s b e l i e v e d t o be a s s o c i a t e d w i t h airways o b s t r u c t i o n a r i s i n g from abnorm a l i t i e s i n mucous s e c r e t i o n s . 3 9 This s u g g e s t s t h a t b e t t e r knowledge of t h e systems r e s p o n s i b l e f o r mucus p r o d u c t i o n and t r a n s p o r t s h o u l d l e a d t o t h e e v o l u t i o n of drugs more e f f e c t i v e t h a n t h e p r e s e n t l y a v a i l a b l e mucolytics and e x p e c t o r a n t s . I n c o n t r a s t w i t h t h e above d i a g n o s t i c c a t e g o r i e s , i n which r e v e r s i b l e changes are o f t e n recognized soon enough t o respond t o a p p r o p r i a t e t h e r a p y , emphysema is p r e s e n t l y thought t o r e s u l t fron t h e i r r e v e r s i b l e d e s t r u c t i o n of l u n g t i s s u e . Consequently, p r e s e n t mettiods f o r h a n d l i n g emphysema are u s u a l l y p a l l i a t i v e o r p r o p h y l a c t i c , and t h e development of r a t i o n a l t r e a t m e n t a w a i t s i d e n t i f i c a t i o n and u n d e r s t a n d i n g of tne underlying disorder. S i n c e t h e o n s e t of emphysema a p p e a r s t o b e a s s o c i a t e d w i t h r e p e a t e d i n j u r y t o lung t i s s u e by i n h a l e d i r r i t a n t s , by i n f e c t i o n , o r by o t h e r f a c t o r s t h a t are as y e t u n r e c o g n i z e d , 2 , 9 i t is r e a s o n a b l e t o s e e k e x p e r i m e n t a l models i n animals s u b j e c t e d t o a comparable c h a l l e n g e . R a t s exposed t o s u l f u r d i o x i d e , l O or dogs t o c i g a r e t t e s m o k e , l l o v e r extended p e r i o d s of t i m e , anci newborn p i g l e t s s u b j e c t e d t o prolonged hypoxia12 were r e p o r t e d t o develop emphysema-like c o n d i t i o n s . I t remains t o be shown t h a t such models a r e an a c c u r a t e r e f l e c t i o n of t h e human d i s ease and, i n t h e i r p r e s e n t s t a t e of development, i t seems l i k e l y t h a t t h e y
Sect. I1 - Pharmacodynamic A g e n t s
84 -
A r c h e r , Ed.
w i l l b e more u s e f u l f o r i d e n t i f y i n g s p e c i f i c f a c t o r s t o b e e x p l o r e d i n d e t a i l t h a n as r o u t i n e t o o l s t o b e used i n d r u g d e s i g n . R e p o r t s s u c n as t h o s e t h a t a s s o c i a t e f a m i l i a l emphysema w i t h serum a l p h a l - a n t i t r y p s i n a e f i c i e n c y l 3 may p r o v i d e u s e f u l c l u e s t o u n d e r s t a n d i n g t h e e t i o l o g y of t h e t i s s u e d e s t r u c t i o n c h a r a c t e r i s t i c of t h i s d i s e a s e . ~ronchodi1ators.--Bronchospasm o f v a r y i n g d e g r e e i s p r e s e n t i n a l l t y p e s of o b s t r u c t i v e l u n g d i s e a s e . 8 , 1 4 T h i s accounts f o r t h e widespread symptomatic u s e of b r o n c h o d i l a t o r s , and t h e y s n o u l d c o n t i n u e t o occupy an important t h e r a p e u t i c p o s i t i o n , even i f t h e r e s h o u l d b e d r a m a t i c improvements i n p r i m a r y t h e r a p y . U e s p i t e t h i s , t h e r e were few s i g n i f i c a n t a e v e l o p m e n t s i n t n i s area d u r i n g 1966 and much of t h e f o l l o w i n g i s a d i r e c t e x t e n s i o n of matters d i s c u s s e d l a s t y e a r . l Recent c l i n i c a l r e p o r t s , which summarize many e a r l i e r s t u d i e s , i n d i c a t e t h a t m e t a p r o t e r e n o 1 may have s i g n i f i c a n t a d v a n t a g e o v e r t h e s t a n d a r a sympathomimetic b r o n c h o d i l a t o r , i s o p r o t e r e n o l , i n terms of s i d e e f f e c t s and o r a l a b s o r p t i o n . 1 5 S e v e r a l p a p e r s reemphasized t h e s u i t a b i l i t y o f t r a c h e a l m u s c l e p r e p a r a t i o n s as a n &r v i t r o t e s t f o r b r o n c h o d i l a t o r a c t i o n . 1 6 Lands and coworkers17 e x t e n d e d t h e i r s t u d i e s of d i f f e r e n c e s i n B - a a r e n e r g i c r e c e p t o r s a t v a r i o u s p h y s i o l o g i c a l s i t e s , and a p o s s i b l y r e l a t e a d i f f e r e n c e between b r o n c h i a l and c a r d i o v a s c u l a r 6 - r e c e p t o r s w a s s u g g e s t e d i n c l i n i c a l s t u d i e s w i t h m e t a p r o t e r e n o l and t h e €5-receptor b l o c k i n g a g e n t s Kd-592 and p r o p r a n o l o l . 3,18 S t u a i e s w i t h t h e methanesulfonamido a n a l o g s of c a t e c n o l amines have shown two, 2l.J-1992 and 1W-1987, t o h a v e good bronc h o d i l a t o r a c t i o n . 19 B r o n c h o d i l a t o r a c t i v i t y , a l o n g w i t h o t h e r p r o p e r t i e s b e l i e v e d t o b e d e s i r a b l e i n a g e n t s f o r t r e a t i n g c o r pulmonale, was r e p o r t e d f o r t h e two non-sympathozimetic s t r u c t u r e s C I B A 31531-Ba2O and w-1988.21 R2 OH R 1 R1 KO y P k H - k H - N H R 2
MJ-1gg2 MJ-1987
CH3S02NH
-CH(CH3)2 CH3
O
C
H
3
y2H5
I
C I B A 31531-Ba
-(CH2)2 e
MJ-1988
A n t i t u s s i v e s a n a klucolytics.--Chaimers ,22 i n a s h o r t r e v i e w of c u r r e n t l y a v a i l a b l e cougti s u p p r e s s a n t s , emphasized t h a t a n t i t u s s i v e a c t i o n m e d i a t e d s o l e l y t h r o u g h i n h i b i t i o n of t h e cou,gh r e f l e x is g e n e r a l l y u n d e s i r a b l e i n c h r o n i c o b s t r u c t i v e l u n g d i s e a s e , and t h a t t h e r a t i o n a l a p p r o a c h t o t r e a t i n g p e r s i s t e n t coughing is t o e l i m i n a t e t h e c a u s a t i v e I t f o l l o w s from t h i s p o s i t i o n t h a t t r a d i t i o n a l cough supirritation. p r e s s a n t s ,23-27 as w e l l as methods which c o n v e n t i o n a l l y i n v o l v e comparisons w i t h c o d e i n e 2 8 i n s i t u a t i o n s where coughing i s a c u t e l y i n d u c e d , 2 9 are l i k e l y t o b e of l i m i t e d v a l u e f o r c h r o n i c u s e . I -
Chap. 9
P u l m o n a r y , An t ia l l e r g y
85
Mor eland
More s i g n i f i c a n t a n t i t u s s i v e a c t i o n s h o u l d be exDected from drugs t h a t act d i r e c t l y on t h e m u c o c i l i a r y system, wnich i s more c l o s e l y 30-32 a s s o c i a t e d w i t h t h e c a u s e of t h e cough. The proceedings of symposia on mucus p r o d u c t i o n , t r a n s p o r t , and f u n c t i o n i n v a r i o u s organs s u g g e s t an a c c e l e r a t i o n of r e s e a r c h i n t h i s area. On t h e o t h e r hand, t h e s c a n t s p a c e devoted t o r e s p i r a t o r y t r a c t s e c r e t i o n s i n G o t t s c h a l k ' s monograph on g l y c o p r o t e i n s 3 3 i s i n d i c a t i v e of an u r g e n t need f o r a d d i t i o n a l f a c t u a l information. The r e s p i r a t o r y t r a c t m u c o c i l i a r y system is r e s p o n s i b l e f o r t h e removal of i n h a l e d f o r e i g n s u b s t a n c e s , and s e r v e s an i m p o r t a n t e m o l l i e n t and p r o t e c t i v e f u n c t i o n ; 34 d e f i c i e n c i e s i n t h e s e f u n c t i o n s would b e expected t o l e a d t o o b s t r u c t i o n o r t o cough-producing i r r i t a t i o n which may b e f u r t h e r aggravated by d e f e c t s i n mucus p r o d u c t i o n . Hence, p o t e n t i a l l y u s e f u l drug a c t i o n s i n c l u d e , (1) a l t e r a t i o n s i n t h e q u a n t i t y a n d / o r q u a l i t y of mucus produced, ( 2 ) a d j u s t m e n t s i n t h e q u a l i t y of mucus by d i r e c t p h y s i c a l o r chemical a c t i o n , and ( 3 ) r e g u l a t i o n of c i l i a r y a c t i o n which, a s s i s t e d by t h e cough r e f l e x , is r e s p o n s i b l e f o r moviri mucus and a t t e n d a n t i m p u r i t i e s outward a g a i n s t t h e f o r c e of g r a v i t y L i t t l e is known about t h e p h y s i o l o g i c a l c o n t r o l of mucus s e c r e t i o n . There is e v i d e n c e f o r t h e involvement of s e r o t o n i n i n t h e c o n t r o l of g a s t r i c mucus s e c r e t i o n (and a g a i n s t a d r e n e r g i c o r c h o l i n e r g i c c o n t r o l ) , 37 and t h e f a c t t h a t g a s t r i c i r r i t a t i o n can produce r e f l e x s e c r e t i o n of mucus i n t h e b r o n c h i o l e s , 2 2 s u g g e s t s common c o n t r o l mechanisms i n b o t h organs. Even less i s known a b o u t t h e p h y s i o l o g i c c o n t r o l of mammalian c i l i a r y a c t i o n ; 38 i n n e r v a t i o n of c i l i a r y c e l l s cannot be d e m ~ n s t r a t e d ~ ~ and no neurohumoral c o n t r o l mechanisms a r e p r e s e n t l y r e c o g n i z e d , 39 a l t h o u g h Speck r e p o r t e d t h a t c i l i a r y a c t i o n i n t i s s u e c u l t u r e s of human n a s a l polyps i s m i l d l y s t i m u l a t e d by a c e t y l c h o l i n e . 40 (The same paper r e p o r t s profound s t i m u l a t i o n of c i l i a under t h e s e c o n d i t i o n s bv ATP.) C i l i a may b e r e s p o n s i v e t o changes i n pH40 o r i o n i c s t r e n g t h , 3 6 and i t was s u g g e s t e d t h a t c i l i a r y b e a t frequency is a f u n c t i o n of t h e amount and v i s c o s i t y of t r a c h e a l s e c r e t i o n s . 41
.(54-36
Perhaps as a r e s u l t of t h i s l a c k of u n d e r s t a n d i n g , e f f o r t s g e n e r a l l y c e n t e r e d on examining t h e f u n c t i o n a l p r o p e r t i e s of mucous s e c r e t i o n s , and Xethods were r e p o r t e d f o r t n e o b j e c t i v e d i s c o v e r i n g means t o a l t e r t h e m . measurement of mucous flow and v i s c o s i t y , which a t t e m p t t o overcome d i f f i c u l t i e s a s s o c i a t e d w i t h t h e non-homogeneous n a t u r e of most samples of b r o n c h i a l mucus and w i t h t h e measurement of such p r o p e r t i e s i n s i t u . 3 6 , 42-45 N - a c e t y l c y s t e i n e , t o j u d g e from t h e number of f a v o r a b l e c l i n i c a l r e p o r t s , has emerged as t h e most u s e f u l , l o c a l l y - a c t i n g m u c o l y t i c a g e n t p r e s e n t l y i n common usage.46 I t s m u c o l y t i c a c t i o n i s presumed t o depend on s u l f h y d r y l - d i s u l f i d e i n t e r c h a n g e r e a c t i o n s which r e a u c e t h e molecular s i z e of mucous g l y c o p r o t e i n s , t h u s lowering t h e v i s c o s i t y of secreted mucus. A r e l a t e d approach, t h e l o c a l a p p l i c a t i o n of 2-4 s o l u t i o n s of u r e a , almost c e r t a i n l y depends upon t h e well-known a b i l i t y of t h i s a g e n t t o a l t e r h i g h e r o r d e r s t r u c t u r e and s o l u b i l i z e b i o l o g i c a l macromolecules i n aqueous s o l u t i o n . 47 The s y s t e m i c d r u g s Bisolvon @ and p i m e t i n e , mentioned l a s t y e a r ,
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c o n t i n u e d t o a t t r a c t a t t e n t i o n . Favorable c l i n i c a l r e p o r t s from t r i a l s w i t h t h e former, a d m i n i s t e r e d o r a l l y , p a r e n t e r a l l y , or by a e r o s o l , have now reached several thousand cases i n t h e European l i t e r a t u r e - - i t s a c t i o n b e i n g v a r i a b l y d e s c r i b e d as a n t i t u s s i v e , m u c o l y t i c , o r e x p e c t o r a n t . S t u d i e s i n r a b b i t s show t h a t t h e d r u g , a t 1 mg/kg o r a l l y , i n c r e a s e s t h e volume of r e s p i r a t o r y t r a c t f l u i d , which is accompanied by a d e c r e a s e i n t h e c o n c e n t r a t i o n of s o l i d s and p r o b a b l e d e c r e a s e s i n t h e concent r a t i o n of g l y ~ o p r o t e i n s . 4 ~These e f f e c t s appear t o p a r a l l e l t h o s e s e e n i n man and s u g g e s t t h a t t h e drug s h o u l d be c l a s s i f i e d an e x p e c t o r a n t . T h i s e x p e c t o r a n t a c t i o n w a s i n h i b i t e d by a t r o p i n e , b u t t h e very l a r g e doses r e q u i r e d (20-40 mg/kg) do n o t appear t o s u p p o r t t h e p r o p o s i t i o n It was t h a t Bisolvon @ a c t s through a s p e c i f i c c h o l i n e r g i c mechanism. p o i n t e d o u t t h a t s i m i l a r a c t i o n s have been r e p o r t e d w i t h emetine and t h e Electron microscopic i p e c a c a l k a l o i d s , as w e l l as w i t h p i l o c a r p i n e . s t u d i e s i n rats showed t h a t B i s o l v o n @ i n d u c e s changes i n t h e s e c r e t o r y c e l l s of t r a c h e a and upper b r o n c h i , and i t was s u g g e s t e d t h a t s e c r e t i o n of m u c o l y t i c enzymes might b e s t i m u l a t e d by t h e drug.49 P i m e t i n e , on t h e o t h e r hand, w a s r e p o r t e d t o be c l i n i c a l l y s u p e r i o r t o aminophylline i n r e d u c i n g sputum volume, e q u i v a l e n t i n r e l i e v i n g cough, and i n f e r i o r i n I t s a i r w a y s - c l e a r i n g e f f e c t , termed "bronchoimproving l u n g f u n c t i o n . p e r v i a n t " , w a s a s c r i b e d t o d e c r e a s e s i n v o l m e , v i s c o s i t y , and adhesiven e s s of abnormal r e s p i r a t o r y t r a c t s e c r e t i o n s . 50 P r e s e n t e v i d e n c e , t h e r e f o r e , does n o t s u g g e s t t h a t t h e s e two a g e n t s act by t n e s a m e mechanism, a l t h o u g h a d d i t i o n a l comparative s t u d i e s t o e s t a b l i s h t h e p o i n t are c l e a r l y d e s i r a b l e . R e s p i r a t o r y Stimulants.--Therapeutic measures t o overcome v e n t i l a t o r y d e f i c i e n c i e s and t o r e d u c e t h e blood carbon d i o x i d e l e v e l s i n obs t r u c t i v e l u n g d i s e a s e were thoroughly d i s c u s s e d by s e v e r a l a u t h o r s . 51 The u s e of c u r r e n t l y a v a i l a b l e r e s p i r a t o r y a n a l e p t i c s i n o b s t r u c t i v e l u n g disease w a s c r i t i c i z e d on t h e b a s i s of t o x i c i t y and s h o r t d u r a t i o n of a c t i o n , 5 2 and t h e u s e of T r i s b u f f e r t o c o r r e c t r e s p i r a t o r y a c i d o s i s w a s q u e s t i o n e d on both t h e o r e t i c a l and p r a c t i c a l grounds. 5 3 R e i n v e s t i g a t i o n of t h e use of c a r b o n i c anhydrase i n h i b i t o r s 5 4 and d i u r e t i c s , 5 5 on t h e o t h e r hand, l e d two groups t o s u g g e s t t h a t i n d i r e c t v e n t i l a t o r y s t i m u l a t i o n through a d j u s t m e n t of kidney f u n c t i o n r e p r e s e n t s a u s e f u l a l t e r n a t i v e . Although t h e l a s t of t h e s e approaches i s t h e most r a t i o n a l , it is obvious t h a t none would be expected t o have any e f f e c t on t h e u n d e r l y i n g d i s o r d e r , which must be a s s o c i a t e d w i t h t h e i n a b i l i t y of d i s e a s e d l u n g t i s s u e t o p r o p e r l y c a r r y o u t i t s f u n c t i o n of oxygen-carbon d i o x i d e exchange. Allergy.--Glynn c a t e g o r i z e d t h e v a r i o u s t y p e s of a l l e r g i c r e s p o n s e s , reemphasizing t h a t a l l e r g y s h o u l d be c o n s i d e r e d a branch of immunology ,56 and t h e immunological a s p e c t s o f delayed h y p e r s e n s i t i v i t y were thoroughly reviewed.57 From t h i s v i e w p o i n t , i t is a x i o m a t i c t h a t advances i n t h e u n d e r s t a n d i n g of a l l e r g i c phenomena can be expected t o depend on p r o g r e s s i n t h e f i e l d of immunology, and t h a t o n l y from t h e l a t t e r s o u r c e w i l l emerge approaches t o t r e a t m e n t t h a t d e a l w i t h c a u s a t i v e f a c t o r s r a t h e r t h a n w i t h symptoms. With t h e e x c e p t i o n of c o r t i c o s t e r o i d t h e r a p y , 5 , 6 + 5 8 which presumably owes a t l e a s t p a r t of i t s e f f e c t i v e n e s s t o s u p p r e s s i o n
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o f t h e immune r e s p o n s e , most a p p r o a c h e s c o n t i n u e t o d + a l w i t h t h e a n t a gonism o f i n f l a m m a t o r y r e s p o n s e s t h a t p r o b a b l y s h o u l d b e c o n s i d e r e d t h e s e q u e l a e o f some p r i m a r y immunological e v e n t . E x t e n s i v e r e v i e w s on t h e r o l e o f m a s t c e l l s 5 9 and m e d i a t o r s t h o u g h t t o b e i n v o l v e d i n i n f l a m m a t o r y r e s p o n s e s 6 0 summarized much of t h e p r e s e n t m e c h a n i s t i c u n d e r s t a n d i n g . Buf f o n i r e v i e w e d t h e p o s s i b l e b i o l o g i c a l s i g n i f i c a n c e o f h i s taminasebl--an area which seems t o h a v e b e e n r e l a t i v e l y n e g l e c t e d i n c o n s i d e r i n g t h e r e g u l a t i o n o f phenomena t h o u g h t t o r e s u l t from t h e a c t i o n o f endogenous h i s t a m i n e . The c o n t i n u e d u t i l i t y o f a n t i h i s t a m i n i c a g e n t s f o r symptomatic t r e a t m e n t o f a l l e r g i c phenomena62~6 3 u n d o u b t e d l y a s s u r e s t h a t h i s t a m i n e w i l l c o n t i n u e t o occupy a c e n t r a l r o l e i n m e c h a n i s t i c s t u d i e s i n t h i s field.
-A n t i-h i s t a~m i n e-s .--Although ~ i t is r e l a t i v e l y e a s y t o p r e p a r e a c t i v e a n t i h i s t a m i n i c compounds w i t h s u b s t a n t i a l e l e m e n t s o f s t r u c t u r a l n o v e l t y , i t r e m a i n s d i f f i c u l t t o i d e n t i f y means f o r i n t r o d u c i n g s i g n i f i c a n t i m provements. A d d i t i o n a l c l i n i c a l t r i a l s w i t h t h e d i b e n z o x a z e p i n e deriv a t i v e S ( p 1 0 6 4 8 6 4 and t h e t e t r a h y d r o q u i n a z o l i n e iIpt-909, 6 5 c i t e d l a s t y e a r , l d i d n o t s u g g e s t i m p r e s s i v e advantages o v e r e x i s t i n g a s e n t s . The d e s i r a b i l i t y of i n c o r p o r a t i n g a component o f a n t i s e r o t o n i n 6 6 a c t i v i t y r e m a i n s a n open q u e s t i o n . Ash and S ~ h i l d , ~on ' t h e b a s i s of 3 v i t r o s t u d i e s w i t h a g o n i s t a n a l o g s o f h i s t a m i n e and w i t h a n t i h i s t a m i n e s , s u g g e s t t h a t h i s t a m i n e s t i m u l a t o r y r e c e p t o r s i n g u i n e a p i g ileum b e d e s i g n a t e d tll r e c e p t o r s . Those r e s p o n s i b l e f o r s t i m u l a t i o n of g a s t r i c acid s e c r e t i o n and i n h i b i t i o n o f rat u t e r u s r e p r e s e n t a n o t h e r t y p e whicn a r e d i f f e r e n t from H i r e c e p t o r s i n terms of a g o n i s t s t r u c t u r e - a c t i v i t y r e l a t i o n s h i p s and i n t h e f a c t t h a t s p e c i f i c a n t a g o n i s t s are unknown f o r t h e s e r e s p o n s e s . L i s h and coworkersb8 p r o v i d e d e v i d e n c e t h a t a d r e n a l e p i n e p h r i n e release c o n t r i b u t e s s i g n i f i c a n t l y t o t h e p r o t e c t i o n of g u i n e a p i g s by a n t i h i s t a m i n e s when t h e h i s t a m i n e c h a l l e n g e is g i v e n i n t r a v e n o u s l y , b u t n o t Accoraingly, they suggest t h a t t h e when i t is a d m i n i s t e r e d by a e r o s o l . l a t t e r r o u t e o f h i s t a m i n e a d m i n i s t r a t i o n s h o u l d p r o v i d e t h e more r e l i a b l e estimate of a n t i h i s t a m i n i c a c t i v i t y . kiowever, r e c e n t s t u d i e s showing t h a t c e r t a i n a n t i h i s t a m i n e s i n h i b i t t h e r e f l e x release of e p i n e p h r i n e i n cats and dogs f o l l o w i n g h i s t a n i n e c h a l l e n g e 6 9 s u g g e s t t h a t i t may b e e x t r e m e l y d i f f i c u l t i n t h e whole a n i m a l t o s e p a r a t e a n t i h i s t a m i n i c a c t i o n s from a d r e n e r g i c e f f e c t s . These f i n d i n g s l e a d o n e t o t h e c o n c l u s i o n t h a t " s p e c i f i c " a n t i h i s t a m i n e a c t i v i t y is s t i l l b e s t measured on s t r i p s o f g u i n e a p i g ileum. The a l t e r n a t e a p p r o a c h of u s i n g h i s t i d i n e d e c a r b o x y l a s e i n h i b i t o r s t o t r e a t d i s o r d e r s a s s o c i a t e d w i t h t h e a c t i o n s of e x c e s s i v e h i s t a m i n e w a s a g a i n s u g g e s t e d by L e v i n e , 7 0 on t h e b a s i s o f f a v o r a b l e c l i n i c a l New r e s u l t s i n m a s t o c y t o s i s w i t h b r o c r e s i n e ( I , NSD-1055, Cl-54998). s u p p o r t f o r t h e v a l i d i t y of t h i s i d e a w a s p r o v i d e d by t h e r e p o r t t h a t h i s t a m i n e b i o s y n t h e s i s i s markedly i n c r e a s e d f o l l o w i n g a n a p h y l a x i s i n r a t s and g u i n e a HO I CH20NH2 pigs.71 I f t h i s pnenomenon p r o v e s t o b e
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g e n e r a l f o r o t h e r t y p e s o f a l l e r g i c r e a c t i o n s , a p o s i t i o n l o n g h e l d by S c h a y e r , 72 e f f i c i e n t i n h i b i t i o n of h i s t i d i n e d e c a r b o x y l a s e may p r o v i d e a means f o r p r e v e n t i n g t h e s l o w l y d e v e l o p i n g symptoms t h a t nave been d i f f i c u l t t o c o r r e l a t e w i t h t h e r a p i d release of h i s t a m i n e from m a s t c e l l s . References
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19.
11,
J. Meier, H. L y d t i n , and N. Z o l l n e r , Ger. Med. Monthly, 1 (1966) ; cf. R. S . McNeill and C. G. Ingram, Am. J . C a r d i o l . , 12,
473 (1966). 1). M. Aviado and F. P a l e c e k , P h a r m a c o l o g i s t , 23, 197 ( 1 9 6 6 ) ; P . PI. L i s h and K. W . Dungan, =id-., 2, 197 (1966).
20.
21. 22. 23. 24. 25. 26. 27. 28. 29.
30.
P u l m o n a r y , A n t i a l l e r gy
9
Chap.
Mor eland
H. J. B u y t e n d i j k and F. Maesen, Med. Thorac., 23, 65 (1966); H. Urunner, K. E i c h e n b e r g e r , M. Meier, M. Wilhelm, and P . Schmidt, E x p e r i e n t i a , 22, 208 (1966); A. J. Georgopoulos, G. M p l a t z a s , and K. Tountas, C a r d i o l o g i a , Suppl., 49, 23 (1966); L. G r a n a t a , G. Losano, and A. Pasque, Arch. I n t e r n . Phamacodyn., 165,191 (1967). 1). M. Aviado, L. E. F o l l e , and J. P i s a n t y , J. Pharmacol. E x p t l . Therap., 76 (1967). R. K. Chalmers, J. Am. Pharm. Assoc., 6 , 538 (1966). H. M. T e r s t e e g e , A. B. H. Funcke, W. J . Louwerse, and W. Th. Nauta, Arch. I n t e r n . Pharmacodyn., 161, 314 (1966). M. Hankovsky and A. K a r o l y i , A r z n e i m i t t e l - F o r s c h . , 16, 622 (1966). C. V. Winder, M. Welford, J. Wax, and D. 'A. Kaump, J. Pharmacol. 161 (1966). E x p t l . Therap., W. Hougs, I. Mdller N i e l s o n , S. Norn, and M. Nymark, Acta Pharmacol. T o x i c o l . , 24, 3 (1966). M. P r o s t , M. Urbain, and R. C h a r l i e r , Helv. Chim. Acta, 49, 2370
155,
154,
(1966). R. Englehorn and E. Weller, Arch. Pharmakol. Exp. P a t h o l . , 254, 170 (1966) K. J. iiahn and H. F r i e b e l , Med. E x p t l . , 4 .l, 87 (1966); M. Lemeignan, G. S t r e i c h e n b e r g e r , and P. L e c h a t , T h e r a p i e , 2,361 (1966); R. Chermat, h. Kornowski and A. J o n d e t , Ann. P h a m . F r a n c . , 24, 181 (1966); B. J. V a k i l , A. J. Mehta, and K. 1). P r a j a p a t , C l i n . Pharmacol. T h e r a p . , 1, 515 (1966); -cf.. H. S e v e l i u s and J . P. Colmore, J. New Drugs, 6, 216 (1966), who d e s c r i b e an o b j e c t i v e
.
c l i n i c a l method f o r e v a l u a t i n g spontaneous cough f r e q u e n c y . S. Jakowska and E. M. Weyer, Ed., " I n t e r d i s c i p l i n a r y I n v e s t i g a t i o n of Mucus P r o d u c t i o n and T r a n s p o r t , " Ann. N. Y. Acad. S c i . , 130,
369-973 (1966). 31.
32.
K. ti. k i l b u r n and J . V. S o l z a n o , Ed., "Symposium on S t r u c t u r e , Function and ?leasurement of R e s p i r a t o r y C i l i a , " Am. Rev. K e s p i r a t . D i s . , 93, P a r t 2 f o r March (1966). D. C. H. Sun and E. M. Weyer, Ed., " G a s t r i c P e p s i n , MUCUS, and C l i n i c a l S e c r e t o r y S t u d i e s , " Ann. N. Y. Acad. S c i . , 140, 665-952
(1967). 33. 34. 35. 36. 37.
" G l y c o p r o t e i n s , " A. G o t t s c h a l k , Ed., E l s e v i e r P u b l i s h i n g Co., Xew York, i\l. Y . , 1966. J. A. G. Rhodin, Ref. 31, p. 1. R. b. G o s s e l i n , Ref. 31, p. 41. S. Carson, K. Goldhammer, and R. C a r p e n t e r , Ref. 31, p. 86. R. Menguy and A. E. Thompson, Ann. N. Y. Acad. S c i . , , & l 797
(1967).
38. 39. 40. 41. 42. 43.
89 -
cf., H .
K i n o s i t a and A. Murakami, P h y s i o l . Rev., 47, 53 (19b7). J. K e n s l e r and S. P. Uattista, Ref. 31, p . 93. A. Spock, Am. Rev. R e s p i r a t . D i s . , 94, 473 (1966). T. Dalhamn, 2, 799 (19b6). S. Carson, R. Goldhamer, and M. S. Weinberg, Ann. N. Y. Acad. S c i . , C.
m.,
130,
935 (1966). B. B a r n e t t and C. E. M i l l e r ,
m.,L32,
8 9 1 (1966).
90 44. 45. 46. 47.
Sect. I1
- Pharmacodynamic Agents
A r c h e r , Ed.
P. C. L u c h s i n g e r , B. LaGarde, J. E. K i l f e a t h e r , and B. G. B e n d l e r , Am. Rev. R e s p i r a t . D i s . , 94, 4 7 1 ( 1 9 6 6 ) . S . K. I-iirsch, R. C. Kory, and L. H. H a m i l t o n , U d - . , 94, 784 ( 1 9 6 6 ) . Anon., B r i t . Med. J . , 603 ( 1 9 6 6 ) .
2,
D. Waldron-Edward and S. C. S k o r y n a , Can. ?fed. Assoc. J . , Y4, 6 7 5 , 1249 ( 1 9 6 6 ) . 48. E. 31. Boyd and P. S h e p p a r d , Arch. I n t e r n . Pharmacodyn., -3.63, 284 (1966). 4 9 . H. Merker, A r z n e i m i t t e l - F o r s c h . , l6, 509 ( 1 9 6 6 ) . 50. B. M. Cohen, J . N e w Drugs, 6 , 162 ( 1 9 6 6 ) . 51. G . J . Beck, G e r i a t r i c s , 21, 139 ( 1 9 6 6 ) ; M. L. R i c c i t e l l i , J. Am. Geriat. SOC., l4, 497 ( 1 9 6 6 ) ; F. B. S a k s e n a and B. Burrows, D i s . C h e s t . , 50, 176 ( 1 9 6 6 ) ; M. J. D u l f a n o and S. I s h i k a w a , Am. Rev. K e s p i r a t . U i s . , 93, 2 5 1 ( 1 9 6 6 ) ; B. H a r v a l d , L. H e n d r i k s e n , and L. Boy, Acta Pled. Scand., 180, 513 ( 1 9 6 6 ) . 52. J. Waddell and P. A. Emerson, C u r r e n t Therap. R e s . , 6, 312 ( 1 9 6 6 ) ; -c f . A. D. S t e e l e and T. Rodman, Am. Rev. R e s p i r a t . D i s . , 94, 600 (1966). 53. ti. L. B l e i c h and W. B. S c h w a r t z , New Engl. J . Fled., L 7 3 , 782 ( 1 9 6 6 ) . 54. A. Naimark and R. M. C h e r n i a c k , Can. Ned. Assoc. J., 9 4 , 1 6 4 ( 1 9 6 6 ) . 5 5 . M. I . M. Xoble, D. T r e n c h a r d , and A. Guz, L a n c e t , 2, 257 ( 1 9 6 6 ) . 56. L. E. Glynn, P r a c t i t i o n e r , 196,759 ( 1 9 6 6 ) . 57. J. W. Uhr, P h y s i o l . Rev., 46, 359 ( 1 9 6 6 ) ; “Delayed H y p e r s e n s i t i v i t y : S p e c i f i c Cell-Mediated Immunity,” B r i t . Med. B u l l . , 23, 1-97 ( 1 9 6 7 ) . 58. L. M. Solomon and H. Beerman, Am. J. Med. S c i . , 478 ( 1 9 6 6 ) . 5 9 . K. K e l l e r , ‘ T i s s u e Mast Cells i n Immune K e a c t i o n s , “ American E l s e v i e r P u b l i s h i n g Co., I n c . , New York, N. Y . , 1 9 6 6 . 6 0 . R. B. S t o u g n t o n , Arch. D e n n a t o l . , 53, 6 0 1 ( 1 9 6 6 ) . 61. F. B u f f o n i , Pharmacol. Rev., 18,1163 ( 1 9 b 6 ) . 6 2 . M. ti. Weinswig, J . Am. Pharm. ASSOC., 6, 550 ( 1 9 6 6 ) . 6 3 . 0 . 3 . Macaulay, P r a c t i t i o n e r , 196, 775 (1906). K. L. S e a l s , 6. N. C r a v e r , a n 5 R. C. Troop, C u r r e n t T h e r a p . R e s . , b4. 8 , 35 ( 1 9 6 6 ) ; A. R. F u r g i u e l e , J. P. High, Z. P. H o r o v i t z , and J . C. Burke, Arch. I n t e r n . Pharmacodyn., 160,4 ( 1 9 6 6 ) . 65. li. J. Lange, Drugs Made i n Germany, 9 , 11 ( 1 9 6 6 ) ; H. B o t t k e and W. G u n t n n e r , A r z n e i m i t t e l - F o r s c h . , l6, 1535 ( 1 9 6 6 ) . b6. E. Marazzi U b e r t i and C. T u r b a , Arch. Intern. Pharmacodyn., 162_, 378 (19b6); L. Julou, R. D u c r o t , M. C. Bardone, J . Y. D e t a i l l e , C . Feo, 3. C. Guyonnet, G. L o i s e a u , and J. P a s q u e t , 1 5 9 , 70 ( 1 9 6 6 ) ; Y . G. P e r r o n , W. F. Minor, M. E. Bierwagen, S . A. R i d l o n , and 14. H. P i n d e l l , J . Xed. Chem., 2, 136 ( 1 9 6 6 ) ; B. Rubin, J . L r a p c h o , and J. P. High, L i f e S c i . , 845 ( 1 9 6 6 ) . 67. A. S . F. Ash and H. 0. S c h i l d , tJrit. J . Pharmacol., 27, 427 ( 1 9 6 6 ) . 6 8 . P. PI. L i s h , S. I . Robbins, and E. L. P e t e r s . J . Pharmacol. E x p t l . T h e r a p . , 153, 538 ( 1 9 6 6 ) . 6 9 . J . S . Barczak and J. R. Vane, B r i t . J . Pharmacol., 1 5 , 728 ( 1 9 6 5 ) . 7 0 . K. J . L e v i n e , S c i e n c e , 154, 1017 ( 1 9 6 6 ) . 7 1 . G . K a h l s o n , L. Rosengren, and R. Thunberg, L a n c e t , 1,782 ( 1 9 6 6 ) . K . W. S c h a y e r , Fed. P r o c . , 24, 1295 ( 1 9 6 5 ) ; cf. K. W. S c h a y e r and 72. E. S e s t o k a s , B i o c h i n . Biophys. Acta, 557 ( 1 9 6 5 ) .
c,
m.,
>-,
Chapter 10. Agents Affecting G a s t r o i n t e s t i n a l Functions William A. Bolhofer and Henry I. Jacoby Merck Sharp & Dohme Research Laboratories, West Point, Pa. Secretion. In t h e past year, publications describing chemical substances that i n h i b i t g a s t r i c secretion were g r e a t l y exceeded by papers devoted t o the study of mechanisms of secretion induction and i n h i b i t i o n . Many of these were concerned mainly with g a s t r i n and i t s synthetic derivatives, s e c r e t i n , histamine, 2-deoxyglucose, and i n s u l i n . Although stimulation of secretion i s not a major objective of medicinal chemistry, knowledge of t h e mode of a c t i o n of stimulato,rs and physiological condit i o n s inducing secretion could be of value i n t h e design of i n h i b i t o r s . Therefore, appropriate papers on secretion stimulation and mechanism have been included i n t h e present review. Gastrin and Derivatives. Recovery of g a s t r i n a c t i v i t y from a n t r a l mucosa by t h e use of techniques such a s u l t r a c e n t r i f u g a t i o n , u l t r a f i l t r a t i o n , and Sephadex g e l f i l t r a t i o n t o minimize fragmentation of proteinaceous material has indicated t o one group of investigators' that g a s t r i n , as it e x i s t s i n the a n t r a l mucosa, i s a l a gev protein than the heptadecapeptide i s o l a t e d by Gregory and Tracy.
5 -
A synthetic derivative of an a c t i v e f r a c t i o n of g a s t r i n , commonly r e f e r r e d t o a s t h e " g a s t r i n - l i k e pentapeptide" o r I C I 50,123, has been f u r t h e r evaluated i n animals and humans and has been used a s an i n v e s t i gational secretory stimulant. This pentapeptide ( I ) c o n s i s t s of t h e from t h e carboxyl end of t h e g a s t r i n tetrapeptide unit, the an amino group with N-(tert-butyloxymolecule, acylated carbonyl) -p-alanine
09
,
.
(CH3)3COCO-p-AlaTryMetAspPheNH2
I
I C I 50,123 increased secretion i n t h e perfused r a t stomach where it had a more rapid onset and s h o r t e r dur t i o n of a c t i o n than g a s t r i n but was only about one-eleventh a s potent.' It was s i m i l a r t o a s t r i n i n t h a t large doses caused an i n h i b i t i o n of secretion i n dogs.
5
In t h e human, I C I 50,123, administered par n t e r a l l y , caused p r a c t i Peak stimulation of c a l l y no c i r c u l a t o r y o r blood pressure changes g a s t r i c output was obtained by i.v. infusion of 0.01-0.1 pg./kg./min.7 I n a single-dose evaluation, 6pg./kg. I C I 50,123 was equivalent t o 40 pg./kg. of histamine a c i d phosphate. No synthetic derivatives of g a s t r i n , other than those already reviewed,g have been described.
.%
gf
The maximum stimulatory response of a c i d output e l i c i t e d by g a s t r i n
i n man was higher than the maximum response t o histamine o r histalog.
92
Sect. II
-
Pharmacodynamic Agents
A r c h e r , Ed.
A t lower doses, a synergistic e f f e c t between histamine and g a s t r i n was found but the maximum secretory e f f e c t of g a s t r i n alone was not potentiated. Atropine had a d i s t i n c t inhibitory e f f e c t on the maximum secretory response t o gastrin.1° The patterns of e l e c t r o l y t e and acid secretion r e s u l t i n g from g a s t r i n stimulation i n man were found t o be very similar t o those following histamine stimulation.ll Secretion of i n t r i n s i c f a c t o r i n man w a s stimulated by gastrin II.12
In the denervated Heidenhain pouch of the oxyntic gland area i n dogs, the maximum acid secretory response t o gastrin I1 and secretion stimulating peptide ( I C I 50,123) was lower than t o histamine.l3 Gastrin has been shown t o have a stimulating e f f e c t on acid secretion from the i s o l a t e d bullfrog mucosa .14 Insulin and 2-Deoxyglucose. The stimulation of g a s t r i c secretion by i n s u l i n and 2-deoxyglucose and the mechanism of t h e i r action has received increased attention. I n pylorus-ligated r a t s , 2-deoxyglucose (2DG (600 mg./kg. ) administ e r e d subcutaneously evoked maximum stimulation.l4 By the same route of administration i n chronic f i s t u l a r a t s , the g a s t r i c response was a l l o r none and t h e threshold dose was approximately 50 m ./kg. Atropine abolished t h e g a s t r i c response t o 2DG i n these r a t s . l g The stimulatory e f f e c t of 2DG on dogs with g a s t r i c f i s t u l a s was completely eliminated by vagotomy. However, 2DG and i n s u l i n both stimulated secretion i n a Heidenhain (denervated) pouch i n dogs a l s o having an open g a s t r i c f i s t u l a (innervated). Closure of t h e f i s t u l a allowed acid from the stimulated s t o r i c h t o bathe the antrum and duodenum r e s u l t i n g i n inhibition of the Heidenhain pouch secretion. The authors suggest t h a t these data demons t r a t e vagal mediated release of g a s t r i n from the pyloric gland area by In similar type experiments, other investigators 2DG and insulin.17 suggest that inhibition of s e c r e t i n i n a Heidenhain pouch by insulin my be due t o l i b e r a t i o n of glucagon. 18 Rats made diabetic by administration of alloxan showed an inhibition of acid secretion which was suggested t o be purely the r e s u l t of the hyperglycemia following the destruction of the beta c e l l s of the pancreas .I9 However, hyperglycemia induced by parenteral administration of d i d not inhibit histamine stimulated g a s t r i c secretion i n r a t s . human diabetics a decrease i n g a s t r i c secretory function was associated with elevated f a s t i n g blood glucose levels .21 After a normal stimulatory e f f e c t , high doses of i n s u l i n (>0.45 U/kg.) i n dogs with g a s t r i c f i s t u l a showed a consistent inhibitory e f f e c t on histamine-stimulated acid secretion22 w i t h the e a r l i e s t observed e f f e c t Restoration of the blood being a reduction of l@ i n the g a s t r i c j ~ i c e . ~ 3 sugar levels by i.v. administration of glucose d i d not reverse the i n h i b i t i o n of acid and @ output, showing t t the inhibition was not r e l a t e d d i r e c t l y t o the i n s u l i n hypoglycemia.' Administration (i.v. ) of potass i u m chloride (1milliequivalen+/kg. ) completely and rapidly reversed the i n s u l i n inhibition of g a s t r i c e l e c t r o l y t e excretion. These r e s u l t s
Chap. 10
Ga s troint e s tinal
Bolhofer and Jacoby
93 -
indicate that the i n s u l i n inhibition might be the r e s u l t of a redistribut i o n of i n t r a c e l l u l a r K+ with depletion of K? f r o m s i t e s e s s e n t i a l t o Potassium chloride a l s o modifi d the inhibitory e f f e c t of secretion.'5 i n s u l i n i n nonhistamine-stimulated animals .2z Rats on a potassium deficient diet f o r four weeks a l s o showed a diminution of g a s t r i c acid secretion which was accentuated by administration of excess mineralocorticoid.27 Secretin, an i n t e s t i n a l hormone obtainable from the duodenum, p a r t i c u l a r l y on acidification, has been used c l i n i c a l l y a s a diagnostic a i d i n pancreatic disease t o stimulate pancreatic secretion. It has been well-established that s e c r e t i n a l s o i n h i b i t s g a s t r i c acid secretion. The most recent investigation showed that s e c r e t i n inhibited gastrinstimulated s e c r e t i n but not that induced by histamine i n dogs v i t h a Heidenhain pouch.28 Insulin r lease by the pancreas i s stimulated by s e c r e t i n i n dogs29 and i n man. 50 The preparation of very pure secretin31 has been described and degradation s t u d i e ~ 3 ~ ~ 3 t3h e pure hormone have permitted a s t r u c t u r a l assignment t o be made. 3493y The assigned structure i s t h a t of a straight chain polypeptide consisting of twenty-seven amino acid u n i t s (11). It shows a resemblance t o glucagon i n that 14 of the amino acid u n i t s (No. 1, 2, 4, 5, 6, 7, 8, 11, 15, 16, 18, 20, 24, and 26 i n 11) i n secret i n occupy the same position i n the peptide chain a s they do i n glucagon. H i s Ser-Asp-GlyJI'hr-Phe4hrSer-Glu-LeuSer-Arg-Leu1 2 3 4 5 6 7 8 9 10111213
F2
SSH:!
-Ar g -Asp Se r -Ala -Arg -Leu -Glu-Arg -Leu -Leu-Glu -Gly -Leu -Va 1 14 1 5 16 17 18 19 20 2 1 22 23 24 25 26 27
I1
The stru ure proposed f o r s e c r e t i n was synthesized by Bodanszky and coworkersS' by two d i f f e r e n t methods. In one, the heptacosapeptide chain was formed by stepwise addition of individual amino acid u n i t s and i n the other, four peptide fragments were combined. However, none of the synthetic preparations have been as potent as the purified secret i n from n a t u r a l sources. Inhibitors of Gastric Secretion. Various other hormonal polypeptides have been the subjects f o r g a s t r i c secretory investigation. Bradykinin showed an inhibitory e f f e c t on g a s t r i c acid secretion i n dogs.37 Angiotensin caused a mod s t inhibition of food induced secretion volume i n Pavlov pouch d 0 g s . 3 ~ Secretion volume but not acid concentration was reduced i n dogs w i t h a Heidenhain pouch by a n t i d i u r e t i c hormone. Oxytocin was without e f f e c t .39
94
Sect. I1
- P h a r m a c o d y n a m i c Agents
A r c h e r , Ed.
A series of 1-(dialkylaminoalky1)benzimid zoles having an inhibitory One representative, effect on gastric secretion has been reported." 1-(2-piperidinoethyl)benzimidazole (111)had an ED of 11.2 mg./kg. for O emptying time was total acid in the rat. At 50-100 mg./kg. p.0. gas5 ric increased and intestinal motility was inhibited. It was concluded that parasympathetic transmission was selectively blocked.
I11
N
v
I mH3
The effect of four adrenergic blocking agent on gastric secrccicg in dogs has been reported by Pradhan and Wingate." Phentolamine and tolazoline induced secretion at 1.2 mg./kg. i.p. Phenoxybenzamine at 20 mg./kg. i.p. and dichloroisoproterenol at 10 mg./kg. i.p. did not; induce secretion and both blocked 'oethanechol induced stimulation in some experiments and histamine induced stimulation (volume and acidity) in all experiments. Under certain conditions, the secretion inhibiting effect of adrenergic agents ( isoproterenol and epinephrine) was partially blocked by dichloroisoproterenol leading to the conclusion that adrenergic inhibition of gastric secretion is mainly a @-receptor function. 2,2' -Bipyridine (N) decreased volume, hydrogen ion, and pepsin output in pylorus-ligated rats b t had no effect on insulin- or histaminestimulated secretion in dogs.x2
3-Methylamino-2,l-benzisothiazole (V) (7.2 mg./kg.; S.C. and p.0.) caused a sharp reduction in volume and approximately lO$ reduction of hydrogen ion concentration in pylons-ligated rats. A dose of 20 mg./kg. i .v. in histamine- or insulin-stimulated dogs with innervated gastric pouches resulted in voluii reductions up to approximately 5% and a very small but statistically significant decrease in acid concentration. 43
The effects of p-chloromercuribenzoic acid, N-ethylmaleimide and iodoacetamide on various enzymes in the gastric mucosa vere studied by histochemical methods. These compounds block gastric acid secretion and also inhibit sulfhydryl-containing enzymes. No conclusion was reached as to whether these inhibitors act by blocking energy-producing systems o r by inhibitit$ a specific enzyme system involved in the production of hydrogen ions. The action of adenosine-3',5'-monophosphate (6-8mg./kg., i.v.) on the human gastrointestinal tract has been determined. Intestinal motility was promptly abolished and, after histamine stimulation, acid output was depressed 35217% although no significant change in volume or pH was
Chap. 10
G a s t r o i n t e s tinal
Bolhofer and Jacoby
95 -
reported. 45 Opipramol ( 5-fi-( B-hydroxyethylpiperazino )propyy-%-diben o( b , f )t6 azepin dihydrochloride) reduced g a s t r i c hyperacidity i n humans. The inhibitory e f f e c t of various anticholinergic agents on g a s t r i c secretion i n t h e human has been t h e ubject of E v e r a l publications. tropenzilene49 These agents include glycopyrrolate c7 poldine, acid e s t e r of 7-metho:ry-N-methyltropinium bromide ), and p i r i b e n z i l ( b e n z i l i c a c i d e s t e r of R,N-dimethyl-2-(hydroxymethyl)piperidinium methyl s u l f a t e ) . Three quaternary ammonium s a l t s of the general s t r u c t u r e benzyl t r i ( f3-alkoxyethyl)ammonium iodide had an i n h i b i t o r y e f f e c t on g a s t r i c secretion i n Shay r a t s . These compounds were reported t o be non-anticholinergic .5l
,
I n humans, estrogens had no e f f e c t on t h e secretion of a c i d or pepsin and probably increased the production of mucus i n the stomach. However, they appeared t o c o n t r o l t h e symptoms of duodenal ulcers.52
I n human u l c e r p a t i e n t s , heparin did not s i g n i f i c a n t l y reduce basal g a s t r i c acid secretion but produced a s i g n i f i c a n t i n h i b i t i o n of the response t o histamine and i n s u l i n stimulation.53 I n guinea pigs, heparin a l s o markedly i n h i b i t e d the g a s t r i c secretory response t o histamine but i n betazole (3-(2-aminoethyl) azole) stimulated animals t h e r e was an It was c o n c l u d d t h a t heparin may have increase i n secretion volune. i t s e f f e c t by binding with histamine. Beparin s i g n i f i c a n t l y i n h i b i t e d secretion i n dogs stimulated with food, i n s u l i n , acetylcholine, methacholine, 48/80, histamine, and gastrin.55
7v
Ulcers. The r e l a t i o n s h i p betwee a c i d and pepsin, 56 n u t r i t i o n a l stateh i s amine59 and h i s t i h e E 0 metabolis s u l f a t e synthesis and S35 uptake,E1 hypophysectomy,22 sex hormones,zj and other on t h e production of "stress" o r drug induced u l c e r s has been studied.
''
Amitriptyline (2.5-10 mg./kg. s.c.) protected male r a t s against immobilization ulce s, while chlordiazepoxide (5-50 mg./kg.) had no protective e f f e c t . Vhen given concurrently, however, t h e proteckive e f f e c t was 1.7 fold greater with t h e combination than with amitriptyline alone. Nortriptyline, chlo romazine,and imipraaine a l l were found t o prevent Shay u l c e r s i n r a t s Y 7 These agents a l s o increased mucin content i n %he g a s t r i c juice. Several pyrimidines (b-methyluracil, 4,6-dihydroxypyrimidine, 2-methyl-&, 6-dihydroxyyyrimidine, cytosine ) caused a 42-72$ reduction i n a s t r i c ulceration produced by repeated o r a l administration 6 ' These compounds apparently stimulate regenerative proof caffeine . cesses and complement t h e e f f e c t of other therapeutics i n t h e treatment of g s s t r i c ulcers. Halidor (1-benzyl-1-( 3-dimethylaminopropoxy )cycloheptane fumarate ) reduc d t h e u l c e r formation due t o 16-20 days of glucose feeding i n ' Restraint and serotonin u l c e r s were a l s o blocked. Phenindione r a t s .9 (2-phenyl-1,3-indandione) therapy i n man was reported t o have induced hemorrhagic u l c e r a t i v e c o l i t i s .To
96
Sect. I1
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Pharmacodynarnic Agents
Archer, Ed.
Powdered aspirin, placed on dog explanted mucosa, blocked histaminestimulated acid secretion. Edema and hemorrhagic petechiae were observed on the e~plant.7~Aspirin ingestion in dogs caused bleeding from isolated gastric pouches which was dose-related.72 Choline salicylate did not produce these changes. Aspirin in suspension or in either of two precipitated solutions at pH 3.0 produced gastric hemorrhage in Pavlov pouch dogs. Salicylic acid, methyl salicylate, salicylamide or acetaminophen solutions did not produce hemorrhage. Neither of the two groups of agents produced hemorrhage when given at pH 6.5.72a Carbonic anhydrase inhibitors decreased the incidence of phenylbutazone induced ulcers in rats with acetazolamide giving complete protection. There was good correlation between diuretic activity of the carbonic anhydrase inhibitors and the degree of antagonism of the ulcers. This was cited as support for the contention that the ulcerogenic activity of phenylbutazone is partly due to stimulation of carbonic anhydrase in the gastric mucosa .73 Motility. Several new methods for the study of gastrointestinal motility in unanesthetized dogs were published in the last year. All utilized chronically implanted transducers attached to the serosal surface of the stomach or intestine. Reinke and coworkers used modified extraluminal strain gage transducers to record contractile activity and tone from circular and longitudinal muscle of stomach, small intestine, and colon in the unanesthetized dog.74 The effect of 5-hydroxytryptophan, neostigmine, morphine, histamine, and hexamethonium on the patterns of contractile activity were described. Rosenbaum et al. analyzed parameters such as shape, force, frequency, and velocity of circular and longitudinal muscle contractile activity.75 Nelson et al. studied the effect of i sulin and feeding on motor activity of the circular muscle of the stomach.7 Renecker and Brendel measured rhythm and intervals of "peristalsis" in the stomach, small intestine, and colon.77 Atropine, neostigmine, and cholecystokinin were studied, none of which altered the frequency of contraction. Passage of a charcoal meal in mice was facilitated by neostigmine, pilocarpine, barium chloride, 5-hydroxytryptophan, and castor oil and inhibited by anticholinergics, papaverine, and ganglionic blockers .7a
8
In a study of acetylcholine receptors in longitudinal muscle of guinea pig small intestine, using tritium-labelled atropine,three components could be distinguished:79 (1) a binding site with a capacity of 180 picamoles/gm., (2) a binding site with capacity about 1,000 picamoles/gm., and ( 3 ) a nonsaturable compartment with a clearance of 4.7 showed that serotonin receptors in an isolated ml/gm. Woolley and Go& strip of rat stomach could be specifically destroyed by two trea ments with purified neuraminidase plus ethylenediaminetetracetic acid.80 The response to serotonin could be recovered by the addition of purified gangliosides indicating these make up part of the receptor. An evaluation of drug effects on otility of isolated strips of human gastrointestinal tract was made.197--83 The pylorus was found to resemble other areas of the gut in its response to drugs but the cardiac
Gastrointestinal
Chap. 10
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Bolhofer a n d J a c o b y
and ileocecal sphincters were pharmacologically d i s t i n c t , being cont r a c t e d by epinephrine and acetylcholine. Cholinergic agents, norepinephrine, and epinephrine caused contraction of c a t longitudinal e s o p h g e a l smooth muscle. The a c t i g e of the l a t t e r .two compounds was blocked bjr tolazoline and atropine. Isoproterenol inhibited esophageal smooth muscle and was antagonized by propranolol. The e f f e c t s of neurohumors and drugs on t h e e l e c t r i c a l and co t r a c t i l e responses of the pyloric region were reported by Daniel. 85 j g 6 Adrenergic agents, cholinergic agents, histamine, serotonin, phenylbiguanide, and morphine were a l l studied and t h e i r mechanism and s i t e of action analyzed. Commercial pre arations of cholecystokinin stimulated p e r i s t a l s i s i n the colon of man 7 and g a l l bladder, stomach, and small i n t e s t i n e i n the dog.88 I n dogs, secretion of n a t u r a l cholecystokinin stimulated by Jejunal perfusion with 0.1 N H C 1 did not produce an increase i small i n t e s t i n a l motility but did produce g a l l bladder contraction. 88
8
Gastrin pentapeptide ( I ) i n doses producing near maximal secretion increased m t o r a c t i v i t y of the of g a s t r i c acid (0.01 mg./kg./min.) antnun i n man.89 Higher doses of pentapeptide were needed t o stimulate colonic a c t i v i t y i n t ~ a n . 9 ~Gastrin I1 i n dos5s of 25 o r 50 pg. i.v. was found t o increase motor action of the d i s t a l colon and rectum, however, the e f f e c t was more pronounced i n t h e proximal portion of the alimentary t r a ~ t . 9 Doses ~ used were 10 times the amount necessary t o e l i c i t acid secretion. Glucagon (9-180 y/kg.) de ressed neostigmine induced motility of stomach, duodenum, and c 0 l o n . 9 ~ No correlation between duration of inhibition and arterio-venous glucose differences was noted. I n a study of the e f f e c t of various narcotic analgesics on the pyloric sphincter i n r a t s , morphine (0.5 mg./kg.), meperidine, and papaverine caused an increase i n flow through t h e pylorus, but dextromoramide and diphenoxylate (ethyl 1- -cyan0 -3,3 -diphenylprop;y.l )-I! phenylisonipecofate ) decreased flow.
-
Several d i f f e r e n t types of antispasmodics have been described. Most of the agents are anticholinergics, however a few appear t o have other a c t i v i t i e s . Nafiverine ( V I , R 1 1-(a-naphthy1)ethyl) showed anticholinergic, antihistaminic, and a n t i serotonin a c t i v i t y and blockade of BaC$ s p s m on i s o l a t e d i l e a l A muscle.9t The e f f e c t on a c t i v i t y CH2CH200CR 9WC1 of variations of R i n V I have been reported.95 Piribenzyl (see ref. 50) VI i n h i b i t e d spasm induced by acetylcholine, histamine, and BaCQ and inhibited i n t e s t i n a l motility i n dogs i n doses of 0.02-0.05 mg./kg. i.v. 96 I n man t h i s compound inhibited g a s t r i c emptying and small i n t e s t i n a l t r a n s i t 97 N -Me t hylbis ( 4-c hlorophenoxy )ace tamide showed a c t i v i t y against acetylcholine, and B a c k sasm of i s o l a t e d r a t duodenum and was effective i n
RCoCCH2CH2YJ -
98 -
Sect. I1
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Pharmacodynamic Agents
A r c h e r , Ed.
i n h i b i t i n g i n t e s t i n a l m o t i l i t y i n t h e mouse .98 It a l s o blocked histamine induced contraction of guinea-pig ileum, histamine hypotension i n dogs, and serotonin diarrhea. Nicotinyl dihydrocodeine i n doses of 8 mg./kg. i . v . decreased p e r i s t a l s i s and tone of dog duodenum a s recorded by the balloon technic. Barium chloride and neostigmine stimulation were inhibited.99 The r e s u l t s a r e t h e reverse of those obtained with dihydrocodeine. C l i n i c a l s t u d i e s indicate t h a t malethamer, a crosslinked copolymer of ethylene and maleic anhydride, was e f f e c t i v e i n the treatment of Anisotropine diarrhea due t o i t s unusual water binding capacity.lOO,lO1 methyl bromide ( 2-propylpentanoyltropinium methyl bromide ) and phenob a r b i t a l provided greater r e l i e f f o r various functional g a s t r o i n t e s t i n a l disorders than t h e anisotropine alone o r belladonna alkaloids with phenobarbital. Ulcerative C o l i t i s . The use of immunosuppressive ;?rugs (6-mercaptopurine, busulfan, 6-thioguanosine azathio rene ) i n experimental therapy Results have been encourof u l c e r a t i v e c o l i t i s has been reported.10y-106 aging i n t h e small group of p a t i e n t s t e s t e d but p o t e n t i a l l y serious side e f f e c t s were observed due t o t h e high doses that were required. Disappointing features a r e t h e f a i l u r e t o achieve a cure and t h e s e v e r i t y of relapse on suspension of treatment.
,
.
Diphenidol ( l,l-diphenyl-4-piperidinobutanol) has Antiemetics been reported t o have antiemetic a c t i v i t y equal t o chlorpromazine, but ny of t h e c e n t r a l nervous system actions of t h e phenothiaIt blocked apomorphine induced emesis by o r a l , i . m . , and r e c t a l administration. I n c l i n i c a l t r i a l s dephenidol was found t o be more Lacebo f o r r e l i e f of nausea and vomiting, with few e f f e c t i v e than side e f f e c t s . It was a l s o found t o be e f f e c t i v e against various types of vomiting i n man i n an uncontrolled experiment.
zzz?dp"
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z,
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S e c t i o n I11 Chemotherapeutic Agents Editor: Lee C. Cheney, B r i s t o l Labs., Syracuse, N.Y.
Chapter 11. A n t i b i o t i c s and R e l a t e d Compounds L e e C. Cheney, B r i s t o l Labs., Syracuse, N.Y.
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General. References c i t e d i n t h i s b r i e f r e p o r t a r e i n t e n d e d a s g u i d e s t o t h e most n o t a b l e chemotherapeutic advances i n t h i s v a s t f i e l d d u r i n g 1966. A n t i v i r a l , a c t i f u n g a l and a n t i n e o p l a s t i c a n t i b i o t i c s are found i n Chapters 13, 1 5 and 16 respectively. The alarming i n c r e a s e i n s e r i o u s i n f e c t i o n s caused by d r u g - r e s i s t a n t gram-negative bacilli'' is a t t r i b u t e d i n p a r t t o t h e ominous phenomenon of " i n f e c t i o u s drug r e s i s t a n c e " i n e n t e r i c b a c t e r i a 3 8 4 ( c f , Chapter 1 2 ) d i s c o v e r e d i n Japan i n 1959. The m a j o r i t y of a l l a n t i b i o t i c - r e s i s t a n t s t r a i n s of E s c h e r i c h i a c o l i , Aerobacter, P r o t e u s , Pseudomonas, K l e b s i e l l a , and Salmonella from c l i n i c a l s o u r c e s a r e capable of t r a n s f e r r i n g multiple-drug r e s i s t a n c e ( R f a c t o r s ) t o s e n s i t i v e s t r a i n s of e n t e r i c bacteria i n mixed c u l t u r e . 5, 6 r T h e i n v i v o t r a n s f e r of drug r e s i s t a n c e h a s been demons t r a t e d F G e n e s r e s p o n s i b l e f o r t h e r e s i s t a n c e c a n be c a r r i e d on extrachromosomal DNA. A deeper i n s i g h t i n t o t h e biochemical and g e n e t i c bases of drug r e s i s t a n c e 9 may hopef u l l y l e a d t o more e f f e c t i v e countermeasures a g a i n s t t h i s " p u b l i c - h e a l t h hazard". The B-lactam a n t i b i o t i c s continued t o be t h e cynosure o f synthesis. Some s t r u c t u r e - a c t i v i t y r e l a t i o n s h i p s of penic i l l i n s l O and c e p h a l o s p o r i n s l l r l2 w e r e d i s c u s s e d . Timely r e p o r t s aimed p r i m a r i l y toward t h e e v a l u a t i o n of t h e newer h i g h l y serum-bound p e n i c i l l i n s d e a l t w i t h t h e c o n t r o v e r s i a l r e l a t i o n s h i p o f drug-serum r o t e i n binding t o c l i n i c a l a n t i m i c r o b i a l e f f e c t i v e n e s s . 138]P4 The crowning i n t e l l e c t u a l achievement of t h e y e a r was Woodward's15 b r i l l i a n t t o t a l s y n t h e s i s of c e p h a l o t h i n (X) and c e p h a l o s p o r i n c ( X I I I ) v i a a key i n t e r m e d i a t e presumably u s e f u l f o r t h e s y n t h e s i s of unique v a r i a n t s of b o t h c e p h a l o s p o r i n s and p e n i c i l l i n s .
Chap. 11
Antibiotics
Cheney
103 -
Uses of chemical1 defined media for producing antibiotics were reviewed. An excellent book on the biosynthesis of antibiotics was p~b1ished.l~ A practical book for physicians and clinical laboratory personnel became available. 18
l6
Penicillins. -- Dicloxacillin (111) was effective in 48 of 49 patients afflicted with pneumococcal and staphylococcal wound infections.19 Against clinical isolates of 2. aureus and S. epidermidis, dicloxacillin was 2 to 3.5 times more active than cloxacillin (11) and oxacillin (I) .I9 Other clinicians found dicloxacillin highly efficacious for oral treatment of infections caused by streptococci and penicillinase-producing R staphylococci. q N H 2 $ p ( L H 3 c H -cHco~HT~~o;~ R
CO Na'H
2
0
I
R = phenyl
IV
R = M H - M = H
I1
R = 2-chlorophenyl
V
R=H;
I11
R = 2,6-dichlorophenyl
2'
M = K
Ampicillin (IV),by virtue of its broad spectrum, continued to be of interest for the treatment of various infections caused by gram-negative orqanisms. In a comparative study, ampicillin was active against 43% of 109 strains of E. coli whereas benzylpenicillin (V) was active against only 9.9% of the same group. 21 Synergism between ampicillin and several @-lactamase-resistant penicillins was observed in the laboratory22,23824 and also in a clinical study involving urinary-tract infections.25 C 6H5CH2CON 'FNfld:3
VI
VII
R1 = CO CH OCOCH
VIII
R1 = CHO
2
2
3
'
Hetacillin (VI)26 has given higher human serum concentrations than those obtained with ampicillin.27 Twelve groups of clinicians studied the effect of hetacillin in over
104
Sect. I11
- Chemotherapeutics
Cheney, Ed.
865 patients afflicted with a variety of gram-positive and gram-negative infections. Notably satisfactory clinical results were reported. 28 After oral administration to the dog, penamecillin (VII), which is the acetoxymethyl ester of benz lpencillin, produces prolonged benzylpencillin serum levels. 24; According to pharmacokinetic evidence30, the penamecillin is slowly absorbed unchanged throughout the intestinal tract and then is rapidly hydrolyzed to benzylpenicillin by nonspecific esterases. Compound VIII is an example of the hitherto unknown penicillin aldehydes for which a general synthesis was developed. 31 Further observations were published concerning the mechanism of action of the penicillins.32-35 Data support the concept that the B-lactam antibiotics inhibit a transpeptidase essential for a cross-linking reaction in bacterial cell-wall synthesis, Transpeptidase derived from cell-free systems of E, coli, like that from S. aureus, is inactivated by penicillins. Thus, the possession of cellular permeability barriers in addition to B-lactamase productive capacity apparently tends to protect gram-negative bacteria from lethal attack by &lactam antibiotics. 3 3 A reliable and rapid procedure was described36 for the iodometric detection of staphylococcal penicillinase in clinical microbiology.
--
Cephalosporins, Many patients with a history of penicillin hypersensitivit have shown no allergic response to cephalothin (XIy7,3 8 t 39 or cephaloridine (XI).40t 41
C02M
X R =
H CO-7 R
1
2
H CH(NH )co-;
= -OCOCH3;
XII
R = D-c
x111
R = D-Hooc-CH(NH~)(CH2 3co-:
-
6 5
2
RI
M
=
Na
: M = FI 3 RI = -OCOCH M = H 3’
= -OCOCH
-
Chap. 11
XIV
R
= 2,6-C1
Antibiotics
C
H CO-;
2 6 4
R
1
Cheney
105 -
= -OCOCH3
In laboratory tests cephaloridine was generally more active than cephalothin against gram-negative organisms.40* 42 In man, average peak serum levels of cephaloridine were double those of cephalothin and more prolonged. 4 0 t 42 * 43 Urinary excretion of cephaloridine was about twice that of cephalothin.40 Anemia developed in several patients receiving cephaloridine.41 Some toxic reactirns associated with cephaloridine therapy were attributed to the low renal clearance of the drug combined with its notable stability in the body.43 Cephaloridine, however, was less effective against enicillinase-producing staphylococci than cephalothin.g2 An improved synthesis44 of ce haloridine was utilized to prepare a series of analogs. 13 A clinical established cephaloglycin (XII)46 as the first reported orally effective cephalosporin. Cephaloglycin, cephalothin and cephaloridine showed comparable activity against most of the gram-negative pathogens tested.45 The known instability of cephaloglycin in solution46 may have contributed to the disturbing side effects noted, namely gastrointestinal distress and severe diarrhea. 45 Semisynthetic cephalosporins, such as XIV were found to protect cephaloridine and cephalothin from decomposition by the enzymes of certain gram-negative bacteria. Because mice can be protected from hitherto resistant infections with a mixture of the enzyme inhibitor and cephaloridine, for example, such combinations may become therapeutically important. 48 Most methods used for the preparation of amides and esters of cephalothin (X) gave rise to the isomeric A2-cephalothin derivatives ( X V ) which have decreased antimicrobial activity. 47 It is known that dry pyridine and other orqanic bases can appreciably CH20COCH3 isomerize the n2compounds to the corresponding cephalosporin C O N H E ? derivatives. 15*49 xv Recent publicatR = amide or ester moiety ions5" 51* 52 have presented substantial evidence for possible cross-allergenicity of the penicillins and cephalosporins. However, direct interaction of the 8-
OCH2
106 -
Sect. 111
- Chemotherapeutics
Cheney, Ed.
lactam of the penicillin nucleus with an amino group of carrier protein (penicilloylation) seems to be the most important mechanism for antigen formation in penicillin allergy. 53 Striking differences between the known chemical behavior of a penicillin @-lactam and a cephalosporin @lactam ring system, even when the side chains are identical, suggest statistically significant differences in sensitizing potential. Furthermore, the nature of the side chain in a penicillin is an important factor in determining antigenic liability.52
--
Methacycline (XVI), marketed in the U . S . Tetracyclines. September, was recently evaluated in the treatment of respiratory-tract infections. 54
XVII
in
R = H; R1 = CH3; R 2 = H:
w OH
0
DOXYCF~~~~(XVII), also a chemical modification of oxytetracycline, gave high, protracted blood levels and showed an activity comparable to demethylchlortetracycline.55 Minocycline (XVIII)56,57 was found more potent than any other reported tetracycline. Efficient oral absorption in animals, unique effectiveness against tetracycline-resistant strains of staphylococci and useful activity against M. tuberculosis H37Rv are all properties attributed to min&ycline.
--
Lincomycin. Antimicrobial potency and spectrum of lincomycin (XIX) have been modified significantly by structural alterations involving changes in the two substituents on the pyrrolidine ring and by replacement of the 7-hydroxy group with a chlorine or a bromine atom. 58 For example, changing the N-CH to N-C H preserved the gram-positive potency and 3 2 5 enhanced the gram-negative activity about tenfold. 7-Chloro7-deoxylincomycin (XX) proved several times more active than lincomycin in vivo against gram-positive bacteria but was inactive, as is the parent, against gram-negative bacteria, Atleast ten U.S. patents concerning various lincomycin derivatives were issued during 1966. Further analogs are under investigation.
107 -
Cheney
Antibiotics
Chap. 11
FH3
XIX
R = OH
XX
R = C 1
CH3CH2CH2
H OH
Rifamycins. -- Systematic chemical modification of rifamycin SV (XXI) has led to remarkable chemotherapeutic improvements which include broadening the antimicrobial spectrum to include gram-negative bacteria, gaining oral activity and obtaining higher stability. Sucha derivative is exemplified by rifaldazine (XXII)59860 which has shown clinical promise in the treatment of respiratory and urinary-tract infections, osteomyelitis and tuberculosis. H
O
XXI
R = H
XXII
R = CH'N-N
U
H
XXIII
F#=O
0
n A N-CH3
3
R = CH2N(CH 3) 2 3 2
H
I
CH
3
R0
Mannich bases (XXIII)61 of rifamycin SV and rifazine,62 a phenazine derivative of rifamycin SV, are other examples of enhanced therapeutic efficacy through structural changes in the natural product. Gentamicin. -- This 2-deoxystreptamine-containing aminoglycosidic antibiotic is related to the n e o m y c i n ~the ~ paromomycins and kanamycin. Clinical reports indicated gentamicin is a drug of choice for parenteral and topical treatment of infections caused by Pseudomonas a e r u q i n ~ s 8a64 ~~ and proteus mirabilis. 6 5 Forty-seven of 50 patients topically treated for various bacterial infections were cleared of
108 -
Sect. 111
infection. drug. 66
- Chemotherapeutic s
Cheney, Ed.
No irritation or sensitization was caused by the
--
Kasugamycin. The unique structure of kasugamycin was established as an aminoglycoside containing a carboxyamidino grouping. 67 This inhibitor of polypeptide synthesis68 has low toxicity and it is of particular interest for treatment of Pseudomonas infections. Spiramycin. -- Hydrolytic removal of the mycarose sugar component of this macrolide antibiotic produced neospiramycin which is twice as active as spiramycin against 2. albus and ~ ~ of facile deacetylation -in vivo -E. -~ o l i . Because acetylspiramycin failed to show any clinical advantages over the parent spiramycin.70 Ranamycin. -- With the exception of Pseudomonas infections, kanamycin has proved to be a valuable antibiotic for the treatment of drug-resistant tuberculosis and serious infections caused by gram-negative bacilli.71 Capreomycin. -- Because of low toxicity and remarkable activity against drug-resistant strains of tuberculosis, capreomycin, a polypeptide antibiotic, was recommended for use in multiple-drug therapy. 72
.;
Chloramphenicol Analogs. -- Microbial kinetics have permitted a more precise quantification of substituent effect on antimicrobial activity in a series of chloramphenicol analogs.73 Re ferences 1.
2. 3. 4. 5. 6.
7.
"Sixth Interscience Conference on Antimicrobial Agents and Chemotherapy", Abstracts, American Society for Microbiology, Philadelphia, Pa., Oct- 26-28, 1966(Papers will appear in "Antimicrobial Agents and Chemotherapy - 1966".) M. Turck, Ref. 1, p 57. T. Watanabe, New Eng. J. Med., 2 7 5 8 888 (1966). T. Watanabe, Federation PrOC.8 2 6 8 23 (1967)F.A. Gill, and E.W. Hook, J. Am. Med. ASSOC., 198, 1267 (1966). T.C. Salzman, and L. Klemm, Ref. 1, p 46D.H. Smith, New Eng. J. Med., 2 ' 7 5 8 625 (1966).
Chap. 11
8. 9.
.
10 11. 12.
13. 14. 15. 16.
17. 18.
19
.
20
.
21. 22.
23. 24. 25. 26.
27. 28. 29.
30. 31.
32. 33
.
34
.
Cheney
Antibiotics
109 -
J . R . Walton, N a t u r e , 2 1 1 8 312 ( 1 9 6 6 ) . M.H. R i c h m o n d , R e f . 1, p 55. K.E. P r i c e , A. G o u r e v i t c h , and L. C h e n e y , R e f . 1, p 13. E.H. F l y n n , R e f . 1, p 14. J.L. Spencer, F.Y. S i u , E.H. F l y n n , B.G. JaCkSOn, M.V. S i g a l , H.M. H i g g i n s , R.R. C h a u v e t t e , S.L. A n d r e w s , and D.E. B l O C h , R e f . 1, p 58. G.H. Warren, C h e m o t h e r a p i a , 1 0 8 339 ( 1 9 6 6 ) . 166 ( 1 9 6 6 ) . C.M. K u n i n , C l i n . Pharmacol. Therap., 7-8 R.B. Woodward, Science, 1 5 3 8 487 ( 1 9 6 6 ) . D. P e r l m a n , A n n . N.Y. A c a d . Sci., 1 3 9 8 2 5 8 ( 1 9 6 6 ) . J.F. S n e l l , Ed., " B i o s y n t h e s i s of A n t i b i O t i C S " , V o l . I , A c a d e m i c Press, N e w Y o r k , N.Y. (1966). V i c t o r L o r i a n , " A n t i b i o t i c s and C h e m o t h e r a p e u t i c A g e n t s i n C l i n i c a l and Laboratory P r a c t i c e " , C h a r l e s C. T h o m a s , S p r i n g f i e l d , Ill. ( 1 9 6 6 ) . C.F. H a m e r s t r o m , F. FOX, M. M c H e n r y , and E.L. Q u i n n , R e f . 1, p 1 7 . A.M.A. Perosio, C.B. A l v a r e z and 0. F u s t i n o n i , R e f . 1, p 88. G. B r e i t f e l l n e r and R. N e U h O l d , C h e m o t h e r a p i a , 1 0 8 2 9 1 (1966). J . A . B a c h , N. B u o n o , D. C h i s h o l m , K.E. Price, T.A. Pursiano, and A. G o u r e v i t c h , R e f . 1, p 75. P. A c r e d and R. S u t h e r l a n d , R e f . 1, p 73. W.E. F a r r a r , Jr., R e f . 1, p 73. L.D. Sabath, H.A. E l d e r , C.E. M C C a l l , N.H. Steigbigel, and M. F i n l a n d , R e f . 1, p 75. G.A. H a r d c a s t l e , Jr., D.A. Johnson, C.A. P a n e t t a , A.I. Scott, and S.A. S u t h e r l a n d , J. O r g . C h e m . , 31, 897 (1966). S.B. T U a n o , L.D. Johnson, J . L . B r o d i e and W.M.M. Kirby, N e w E n g . J. M e d . , 275, 635 ( 1 9 6 6 ) . R e f . 1, pp 1 5 , 16, 81, 8 5 , 86, 8 7 , 88, 89, and 91. H.P.K. A g e r s b o r g , A. B a t c h e l o r , G.W. C a m b r i d g e , and A.W. R u l e , B r i t . J. P h a r m a c o l . , 26, 649 ( 1 9 6 6 ) . M. G i b a l d i and M.A. S c h w a r t z , ibid., 28, 360 ( 1 9 6 6 ) . W.J. G o t t s t e i n , G. E . B o c i a n , L.B. C r a s t . K. D a d a b o , J.M. E s s e r y , J.C. G o d f r e y and L.C. C h e n e y , J. O r g . Chem., 318 1 9 2 2 ( 1 9 6 6 ) J.T. Park, Symp. Soc. G e n . Microbiol., 1 6 8 70 ( 1 9 6 6 ) . J.L. S t r o m i n g e r , K. I z a k i , M. Matsuhashi, and D.J. T i p p e r , F e d e r a t i o n Proc. 2 6 8 9 (1967). Y. A r a k i , A. S h i m a d a , and E. I t o , B i o c h e m . B i o p h y s . R e s . C o m u n . 8 23, 518 ( 1 9 6 6 ) ( E n g . )
.
Sect. 111 - C h e m o t h e r a p e u t i c s
110 -
Cheney, Ed.
K. I z a k i , M. Matsuhashi. and J . L . Str ominge r , Proc. N a t l . A c a d . S C i . U . S . , 3, 656 ( 1 9 6 6 ) . R.G. C o o p e r , G.W. B r o w n , and B.V. V e s e y , A u s . J. E x p . 36. B i o l . Med. Sci., 4 4 8 715 ( 1 9 6 6 ) . 37 , R.L, P e r k i n s and S . S a s l a w , A n n . I n t e r n a l Med,, 64, 1 3 (1966) I.M. S m i t h , D. C a s t l e , C.H. R h o d e n , and S. R a b i n o v i t c h , 38. R e f . 1, p 38. P. N a u m a n n , A r z n e i m i t t e l - F o r s c h , I 1 6 8 1099 ( 1 9 6 6 ) 39. R.A. L a n e , F. C o x , M. M c H e n r y , and E.L. Q u i n n , R e f . 1, 40. p 61. G . F . Thornton and V.T. A n d r i o l e , Y a l e J. B i o l . M e d . , 2, 41. 9 (1966). 42. M. Turck, D.W. B e l c h e r , A. R o n a l d , R.H. S m i t h , and J.F. Wallace, A r c h , I n t e r n a l M e d . , 1 1 9 8 50 ( 1 9 6 7 ) . S.B. Tuano, J.L. B r o d i e , and W.M.M. 43 K i r b y , R e f , 1, p 61. 44 J.L. Spencer, F.Y. S i u , B.G. Jackson, H.M. H i g g i n s , and E.H. Flynn, J. O r g . C h e m , , 3 2 8 500 ( 1 9 6 7 ) . A. R o n a l d , M. Turck, and R.G. 45. P e t e r s d o r f , R e f . 1, p 59. J.L. Spencer, E.H. F l y n n , R.W. R o e s k e , F.Y. S i u , and 46. R.R. C h a u v e t t e , J. Med. Chem., 9-8 746 ( 1 9 6 6 ) . R.R. C h a u v e t t e and E.H. Flynn, J. M e d . Chem., 9 , 7 4 1 47. (1966). 48. Muggleton, S.M. K i r b y , and D.M. C.H. O ' C a l l a g h a n , P.W. R y a n , R e f . 1, p 74. 49 J. D. C o c k e r , S. E a r d l e y , G . 1 , G r e g o r y , M.E. H a l l , and A.G. Long, J. C h e m . SOC.8 C.8 org., 1966, 1 1 4 2 . 50. M.H. G r i e c o , A r c h . I n t e r n a l Med., 1 1 9 8 141 ( 1 9 6 7 ) . 51. R. Thoburn, J.E. Johnson 111, and L.E. c h f f 8 J. Am. Med. ASSOC., 345 ( 1 9 6 6 ) . F.R. B a t c h e l o r , J.M, D e w d n e y , R.D. Weston, and A.W. 52. W h e e l e r , Immunology, 1 0 8 2 1 ( 1 9 6 6 ) . C.H. Schneider and A.L. de Weck, H e l v . C h i m . A c t a , 49, 53. 1707 ( 1 9 6 6 ) L.G. S m i t h , R e f . 1, p 89. 54 55 J.E. B a r r e t t , J.L. B r o d i e , and W.M.M. K i r b y , R e f . 1, p 19. M a r t e l l , Jr., and J.A. B o o t h e , J. Med. Chem., 1 0 8 56. M.J. 44 ( 1 9 6 7 ) . 57 G,S. R e d i n , R e f . 1, p 69. 58. B . J . M a g e r l e i n , R e f , 1, p 14. P. S e n s i , N. Maggi, S. Furgsz, and G. M a f f i i , R e f . 1, 59 p 13. 60. L e p e t i t Sop.A.8 N e t h . A p p l . 6,5098961 ( 1 9 6 6 ) : C h e m . 5462 ( 1 9 6 6 ) . A b s t r . 8 9,
35.
.
.
. .
.
198,
.
0
. .
.
Chap. 11 61. 62.
Antibiotics
Cheney
L e p e t i t S.p.A. Belg. 661,982 ( 1 9 6 5 ) ; Chem. A b s t r . , 65, 5475 (1966) G.G. G a l l o , C.R. P a s q u a l u c c i , N. Maggi, R. B a l l o t t a , and P. S e n s i , Farmaco, ( P a v i a ) Ed. Sci., 21, 68 (1966) (Eng.); Chem. A b s t r . , 19599 ( 1 9 6 6 ) . A.A. Moss, P.A. Bunn, and J , S , Lunn, Ref. 1, p 90. M. Barber and P.M. Waterworth, B r i t , Med. J., 203 (1966) E.S. Wally, Ref. 1, p 86. E.L. Bodian, C u r r e n t Therap. R e s . C l i n . E x p t a l . , 8, 575 (1966). Y. Suhara, K, Maeda, H. Umezawa, and M. Ohno, T e t r a h e d r o n L e t t e r s , 1966, 1239. N. Tanaka, Y , Yoshida, K. S a s h i k a t a , H. Yamaguchi and H. Umezawa, J. A n t i b i o t . (Tokyo), S e r . A , 1 9 , 65 (1966) (Eng.)R . J . Adamski, H. Heymann, S,G. G e f t i c and S.S. B a r k u l i s , J. Med. Chem., 9 , 932 ( 1 9 6 6 ) . M. M a t s u s h i t a , M. Yuasa, M. Imamura, and S . Mihara, J. A n t i b i o t . (Tokyo), S e r . B, 305 (1966): Chem. A b s t r . , 65, 15930 ( 1 9 6 6 ) . M. F i n l a n d , Ann. N.Y. Acad. S c i . , 132, A r t . 2 , 1045 (1966). W.S. Schwartz, Am. Rev. R e s p i r a t . D i s e a s e s , 94, 858 (1966). E.R. G a r r e t t , O.K. Wright, G.H. M i l l e r , and K.L. Smith, J, Med. Chem., 9 , 203 ( 1 9 6 6 ) .
.
2,
63. 64. 65. 66. 67. 68
.
69, 70.
I,
.
-
19,
71.
72. 73.
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Chapter 12. Synthetic Antibacterial Agents Robert G. Shepherd and Arthur Lewis Lederle Laboratories, American C y a n d d Co., P e a r l River, New York Perspective.-Work on these agents i n 1966 w a s directed toward improvement i n the l e v e l of a c t i v i t y or i n the pharmacology of known active struct u r e s . No new a n t i b a c t e r i a l type a c t i v e i n animals or i n m a n was reported. Several sulfanilamides and other synthetic a n t i b a c t e r i a l s as well as the 2,3 Infectious a n t i b i o t i c s a r e involved with "infectious drug resistance. drug resistance denotes t h e transmission of d r u g resistance from one bacterium ( s o far only Gram-negatives) t o another of the same or d i f f e r e n t s t r a i n , species, or genus. This i s accomplished by conjugation: formation of a temporary i n t e r c e l l u l a r connection between two sex types and unidirect i o n a l t r a n s f e r of the resistance genes and a t r a n s f e r a b i l i t y factor, usua l l y associated with an extra-chromosomal sex-determining f a c t o r . Conjugation leads d j r e c t l y t o a new r e c i p i e n t s t r a i n with a comparable l e v e l of resistance. The surprising f a c e t of t h i s phenomenon i s the simultaneous t r a n s f e r of r e s i s t a n c e t o a whole s e r i e s of chemically and biochemically unrelated antimicrobials (most c m o n l y sulf anilami de s t e t r a c y c l i n e s streptomycin, and chloramphenicol but a l s o more recently p e n i c i l l i n s , kanamycin, neomycin, n a l i d i x i c a c i d and nitrof'urans). There appears t o be a close genetic r e l a t i o n s h i p between the resistance genes which leads t o t h e i r beccaning arranged imme a t e l y adjacent t o one another i n the genetic element ( D W ) t r a n ~ f e r r e d . 5 , ~ I snp i t e of requiring several minutes and the proper physiological conditions, conjugation does occur i n vivo, even though l e s s r e a d i l y l ~ ~ t h ainn v i t r o . Resistant b a c t c r i a can be ffcured'f of i n f e c t i o u s drug r e s i s t a n c e with various acridines i n v i t r o , a l b e i t with low frequency;l,2,3,5usually t h e cure applies t o a l l the resistance f a c t o r s but some segregation has been achieved.5~6 The t r u e chemotherapeutic significance of this phenomenon i s not defined a t t h e moment8 but it requires c a r e f u l scrutiny since it involves so many drugs and so many organisms (Coli, Salmonella, Klebsiella, Shigella, Vibrio). Perhaps, by means of t h i s new look a t a b a c t e r i a l l y o l d process, we will now be able t o devise a cure f o r t h i s " i n f e c t i o u s disease'' of b a c t e r i a which will be e f f e c t i v e i n vivo and w i l l f i n a l l y enable us t o deal with the important problem of b a c t e r i a l resistance ( c f . a c l i n i c a l study9 of a t e b r i n i n combination therapy of multi-drug-resistant urinary infections). I n Vivo Actives.-The Gram-negative a c t i v i t y of n a l i d i x i c acid I i s seen from f u r t h e r work t o be very s t r u c t u r a l l y specific. Several 1,5-naphthyridine analogs apparently had l i t t l e , i f any, a c t i v i t y i n v i t r o or i n vivo while one 1,6-ana1og (3-carboxy-boxo-1,5,7-trimethyl-l, 6-naphthyridine) was p a r t i a l l y e f f e c t i v e against Kleb. pneumoniae i n mice (7@0 survival with subcut. 2OOmg/kg/day) .loThe intermediate d i e t h y l N-( 2,6-dimethyl-bpyridy1)amino-methylenemalonate had some i n vivo Staph. a c t i v i t y (6@ survival
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with subcut. lOOmg/kg/day) Curiously, t h r e e 1,7-naphthyridinesl1 had only Gram-positive a c t i v i t y : 1,6,8-trimethy1-3- carboxy-boxo-lJ7-naphthyridine was a c t i v e against Staph., Strep. and Pneumococcus ( p a r t l y e f f e c t i v e ) a t 25, 100 and bOmg/kg/day o r a l l y i n mice; the lY8-dimethyl-6-ethyl and t h e 1e t h y l analogs were much l e s s active.
H
0
I1 I11 IV I Several types of nitrof'urans (NF = 5-nitrc-2-fbyl) with i n t e r e s t i n g l e v e l s of i n vivo a c t i v i t y were reported but margins of s a f e t y were not given. The 4-aminoquinazolines I1 [Z = N(CH3)C2H40HY N(C2H)+OH)2and NHC)+H8-1-pyrrolidinyl] had a broad i n v i t r o spectrum, including seudmonas, Proteus and Aerobacter, and high a c t i v i t y (0.01-12mcg/ml) .15 However, only a c t i v i t y i n vivo against Staph. aureus was reported ( E i n t r a p e r i t o n e a l 1-15mg/kg) ; a c t i v i t y c o r r e l a t e d poorly with data. Homologs of CH3 were l e s s active. Pyridazinone I11 and i t s dihydro intermediate13 were about equal i n vim and i n v i t r o i n Salm.-Staph. activi t y ; 2-alkylation lowered t h e i n v i t r o a c t i v i t y of both. I n contrast, it increased t h e i n vivo a c t i v i t y of t h e former and decreased t h a t of t h e l a t ter. Their i n v i t r o a c t i v i t y (min. inhib. concn. 2-6mcg/d) was l e s s than t h a t of I1 (0.05-0.8mcg/d) while t h e i n vivo a c t i v i t y was the same. Also poorer i n a c t i v i t y i n v i t r o and i n spectrum was t h e t r i a z o l e I V which had comparable Salm.-Staph. a c t i v i t y i n vivo (ED50 20-40mg/kg) .I4 1-Acylation or 5-alkylation decreased i t s a c t i v i t y which w a s g r e a t e r than t h a t of t h e upen-chain N-formylamino nitrof'uramidine, i n t u r n more a c t i v e i n vivo than t h e anddine i t s e l f . The l-methylcarbamoyl-5-imino derivative o f I V w a s a c t i d 5 against Staph., Salm. and Coli i n mice a t about 4Omg/kg with an oral LD 0 of 1 9 0 . A s e r i e s of 2-(5 '-nitro-2'-fluyl)CH=CHpyridines showed he following s i n g l e i n t r a p e r i t o n e a l anti-Salmonella a c t i v i t y ( EDF0 2-10mgjkg; oral ED5 5-75mg/kg) r e l a t i o n s h i p i n mice: 6-CH2OH-l-oxide = 5-CH20Ac-l-oxide > t-CH$Ac-l-oxide > 5-CFi2OAc > ~ - C H ~ O = H 5-CH OH > 6-CH20Ac with approximately t h e same r e l a t i o n s h i p of t o x i c i t y $ The 5methyl-1-oxide reported l a s t year had canparable a c t i v i t y . The a s - t r i a z i n e derivative V was p a r t l y effective17 against Staph. and Salm. i n f e c t i o n s i n mice a t lOOmg/kg. Activity of 5-methylmercapt methyl-+( 5 ' - n i t r o f b f u r y l ideneamino)-oxazolidin-2-one w a s unpromising18 i n various urinary infect i o n s i n a small c l i n i c a l trial. Further c l i n i c a l investigations have confirmed the e f f i c a c y of ethambut o 1 (EMB), (+)-N,N'-bis( l-hydroxy-2-butyl)ethylenedi~ne, i n treatment of pulmonary tuberculosis and a l s o demonstrated i t s use against r e n a l and e treatment of pulmonary i n f e c t i o n s due vesical tuberculosisY19 t o a t y p i c a l mycobacteria. I n controlled t r i a l s conducted i n the National Sanatoria of Japa.n2s t o determine t h e b e s t t h i r d component of a t r i p l e regimen with i s o n i a z i d (INH) and streptomycin (SM) i n o r i g i n a l treatment, cycloserine and p-amino-salicylic a c i d (PAS) were l e s s e f f e c t ive and more t o x i c than EX3 while ethionamide w a s as e f f e c t i v e s EMB but l e s s well t o l e r a t e d ( c f . a dose-response c a p a r i s o n i n monkeys2'). In a
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companion trial, 25 ethambutol ( l g d a i l y ) cambined with e i t h e r cycloserine (0.5g d a i l y ) o r ethionamide (O.5g d a i l y ) was well t o l e r a t e d and h i g h l y e f f e c t i v e i n t u b e r c u l o s i s re-treatment ( r e s i s t a n t t o SM, INH and PAS). I n t h e s e t r i a l s a diminution i n v i s u a l a c u i t y occurred i n about 8 2 of t h e pat i e n t s receiving l g d a i l y ; t h e e f f e c t was r e v e r s i b l e . h i s i cidence and r e v e r s i b i l i t y w a s observed i n o t h e r c l i n i c a l s t u d i e s . 2 ?27,2j29 A reduced dosage regimen30 avoided t h e v i s u a l disturbance While EMB by i t s e l f i s e f f e c t i v e a g a i n s t a c u t e and chronic t u b e r c u l o s i s , 28,30J 31 combined t h e r apy i s r e c m e n d e d t o avoid emer ence of r e s i s t a n t mycobacteria. I n man, about 10,;of EMF3 i s metabolized 27 t o t h e i n a c t i v e d i c a r b o x y l i c a c i d by t h e sequence -CH;zOH + -CHO j -C02H. A s t r u c t u r e - a c t i v i t y has defined t h e very s p e c i f i c requirements f o r a c t i v i t y i n an extensive s e r i e s of EMB analogs
=
8
8
?!2H5 s"
"H2
.
TzH5 \
s" t\ d/
m2 VI
V VIII I n combination with SM, ethionamide (ETH, l g d a i l y ) was as e f f e c t i v e as IhW (0.3g d a i l y ) i n m a n by t h r e e t h e r a p e u t i c c r i t e r i a . However, t h e ETH regimen w a s considered t o be t o o t o x i c t o be c l i n i c a l l y acceptable.33 C l i n i c a l incidence of s i d e - e f f e c t s from ETH ( p l u s INH). decreas d sharply f o r 0.75g and 87: f o r O.5g d a i l y . 3E Separation with dosage: 31% f o r lg, 18;; and c h a r a c t e r i z a t i o n o f ETH m e t a b o l i t e s has been achieved and t h e i r quantit a t i v e i n t e r r e l a t i o n i s under s t u The m a j o r i t y of ETH i s metabolized and r a p i d l y e x c r e t e d i n t h e u r i n e 3 5 A s u b s t a n t i a l m o u n t i s converted t o i t s sulfoxide VI which has now been shown t o be e u a l y a c t i v e and i n t e r ,3~ metaboc o n v e r t i b l e w i t h ETH i n man and o t h e r s p e ~ i e s . 3 ~ ~ 3 7Extensive l i s m t o i n a c t i v e compounds a l s o occurs by d e t h i a t i o n ( d i r e c t l y or, more probably, through t h e s u l f o x i d e ) t o t h e carboxamide, deamidation leading t o 2-ethyl i s o n i c o t i n i c acid, and by 1-methylation t o give VII, which i s p a r t l y converted t o 11. Dethiated VII and VIII and t h e sulfoxide of VIII were a l s o observed. Continued work on sulfanilamides includes s t u d i e s on t e s t s t o guide t h e i r use, new uses, new compounds, metabolism, p r o t e i n binding, and a t o x i c i t y warning. An improved method f o r determining b a c t e r i a l s e n s i t i v i t y t o s u l f a d r u g s permits r e l i a b l y t & i n g advantage o f t h e i r a c t i v i t y a g a i n s t 80-9@ of E. c o l i and Proteus m i r a b i l i s ur2nary i n f e c t i o n s i n gene r a l p r a c t i c e , i n b a c t e r i u r i a of pregnancy and i n h o s p i t a l patients.39 Synergism between t h e i n e f f e c t i v e polymyxins and t h e b a c t e r i o s t a t i c s u l f a d r u g s i n v i t r o , using a number of s t r a i n s of Proteus m i r a b i l i s and vulgari s , l e d t o an 8- t o 6 b f o 1 d decrease i n a c t i v e concentration and t o bactericidal actionb, 41 ( c f . i n vivo work i n 1963). N o such i n t e r a c t i n occurred Plaswith e i t h e r of t h e s e agents when combined with f i v e modium falciparum s t r a i n s r e s i s t a n t t o chloroquine and quinine r e c l i n i c a l l y s u s c e p t i b l e t o sulfanilamides and diaminodiphenylsulfone. &2j43 Sulfasymazine "appea:c4to be a usef'ul agent i n t h e treatment of b a c t e r i u r i a during pregnancy. U s i n g t h e computer method r e c e n t l y reported, The
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dosing i n t e r v a l and the maintenance dose f o r sulfasymazine has been calculated.45 A s i n other s u l f a n i l m i d o heterocycles, introduction of bromine or chlorine i n t o the heterocycle increased t h e persistence& of 4-sulfa-2,6dimethoxypyrimidine; acute t o x i c i t y and p r o t e i n binding were a l s o increased. The isomeric 5-sul a- 3 - e t h y l - l , 2 , b t h i a d i a z o l e and 2 - e t h y l - l , 3 , b t h i a d i a zole were compared 7 as t o d e t a i l e d differences i n r e n a l elimination chara c t e r i s t i c s independent of p r o t e i n binding. C l i n i c a l and pharmacological studi@ were done on extremely long-acting 4- sulfa-5,6- dimethoxypyrimidine, and on t h i s and four other long-acting sulfa drugs (3-sulfa-6-methoxypyridazine, 4-sulfa-2,6-dime hoxypyrimidine, 2- sulfa-5-methoxypyrimidine and 2-sulfa-3-methoxypyrazine). 89 A study50 of 2-sulfanilamidopyrimidine i t s e l f rounds out the p i c t u r e of the metabolism of ulfapyrimidines : 5 l l a r g e variations i n N4-acetylation, i n N4-sulfonate, N -glucuronide and N1-glucuronide formations occur i n closely r e l a t e d compounds. The 5,6-dimethoxy- and 2,6-dimethoxy- &sulfapyrimidines a r e $ and 8G6 converted t o glucuronides. I n contrast t o these 2-sulf&4,6-dimethoxypyrimidine i s not N4and other sulfapyrimidine - a c e t y l derivative is, i n f a c t , r a p i d l y deacetyacetylated i n vivo; i t s lated. Further study of s u l f a drug p r o t e i n binding has indicated t h a t t h e r e i s more t o i t s e f f e c t on a n t i b a c t e r i a l a c t i v i t y than ,just the Dercent bound a t equilibrium under s p e c i a l conditions. Human serum w a s found t o increase the minimal i n h i b i t o r y concentration f o r both sulfadiazine and sulfadimethoxine but the increase for each was eight times as great; f o r Shig. dysent e r i a e as f o r E, c 0 l i . 5 ~In addition, the r a t i o of t h e increases i n m.i.c.'s of the two s u l f a s i n the presence of 20-5C$ human serwn was too s m a l l ( 2 ) t o correspond t o the r a t i o (42) of percentage of unbound sulfa. The binding capacity of human serum p r o t e i n determined by equilibrium dialysis53 w a s nearly the same (ca. 2 moles/mole protein) f o r 8 sulfanilanides (pKa's 5.77.2), t h i s s m a l l capacity supporting chemical. r a t h e r than absorptive binding; p r o t e i n a f f i n i t i e s varied a hundred-fold. A quite d i f f e r e n t number ( ) of binding s i t e s f o r one of these, sulfamethoxypyridazine, was calculated from thermodynamic data based on e q u i l i b r a t e d Sephadex columns; the energ e t i c s indicated binding by van der Waal's forces. R warning has been issued t o physicians t h a t the long-acting sulfcnild d e s , sulfamethoxypyridazine and sulfadimethoxine, have been implicated i n the development of Stevens-Johnson syndrome.55 Over t h e years, many other d m g s and c e r t a i n conditions ccination, foods, i n f e c t i o n s themselves) have a l s o been i m p l i ~ a t e d , 5 ~ 'a,nd t h i s very low incidence syndrome may be an a l l e r g i c r e a c t i n with multiple etiology o r may have a single, s t i l l undetermined cause. 5 Quinoxaline di-N-oxides, which were extensively investigated 15-20 years ago as antiviral, amebicidal and a n t i b a c t e r i a l agents, have received some f u r t h e r attention. Compounds such as 2,3-dimethylquinoxaline-l, &dioxide the r e s u l t of rapid metabolism t o t h e were shown57 e a r l i e r t o be a c t i v e hydroxymethyl analog. Recent work5 has disclosed a l s o the b i s ( hydroxymethyl) metabolite, which w a s s t i l l more active. However, t h e t o x i c i t y increased as d i d t h e a c t i v i t y and precluded chemotherapeutic use.@ The mono and b i s acetoxymethyl analogs were found59 t o have reasonable Gram-negative a c t i v i t y (5C$ survival a t 20-12Omg/kg i n t r a p e r i t o n e a l l y ) i n mice but near t o x i c levels. A quinoxaline-l,h-dioxide-2-aldehyde hydrazone (R-CH=N-r-mx-
f
6
8
?(i
6
2
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olidin-2-on-3-yl), o r a l l y a c t i v e against Pasteurella i n mice ( ~13mg/kg) 4 ~ and i n a Proteus urinary i n f e c t i o n model i n r a t s (min. effective'aose 3m@;/kg)," i s possibly r e l a t e d more t o i t s nitrofbrfurylidene analog, i'urazolidone, than t o the dioxides above, since the active s e r i e s here comprises only hydrazones. No t o ' c i t y e l a t i o n s h i p t o e i t h e r w a s indicated. reported the a c t i v i t y of three ammonium bisThree recent papers quaternaries, ZCH2(Me2)N-C6H&M(Me2)CH2Z where Z i s CllH23, COOC12H25 and COOCloH21, against a l e t h a l Klebsiella rhinoscleramatis i n f e c t i o n i n mice, i n t r a p e r i t o n e a l dosage of 2-5mg/kg twice d a i l y f o r 1 2 days giving 100% surand no data or vival. The LD50 5-iwl-e dose values given were comment on a c t i v i t y against o t h e r orgmisms was given. Antiseptics ( I n V i t r o Actives) .-Compounds a r e included here i f reasonably complete experimental i n d t r o data have been reported-inactivity i n vivo i s assumed unless t h e a r t i c l e s t a t e s o t h e n d s e . For assessing p r a c t i cal a p p l i c a b i l i t y , t h e e f f e c t of p r o t e i n and l i p i d on i n v i t r o a c t i v i t y and t o x i c i t y data a r e necessary but a r e frequently lacking. I n v i t r o structurea c t i v i t y s t u d i e s on i n vim a c t i v e s a r e covered i n t h a t section. N o i n v i t r o antituberculous r e p o r t s have been included.
1%1,62,G +
The b' y c l i c IX (f'urazolium chloride as i t s salt) had broad-spectrum a c t i v i t & t (O.b12mcg/ml) s u b s t a n t i a l l y superior t o t h a t of nitrof'urazone and comparable t o t h a t of nitrofhrylacrylamide. C-Methyl s u b s t i t u t i o n or r i n g expansion decreased a c t i v i t y while i n s e r t i o n of a vinyl group increased a c t i v i t y against Staph., Strep. and Aerobacter. The b i s ( n i t r o v 1 ) X had Coli-Staph. a c t i v i t y comparable t o I X but a narrower spectrum. 5 Same aryl and heteroaryl pyrazoles and isoxazoles X I were about as active66 (0.2t'vireported e a r l i e r . The a s - t r i a z i n e X I 1 had broad but apparently not as broad as t h e vinyl a n a 1 0 g , ~ ~ , or ~g the ~ - N ( C H ~ O A Cderivative )~ of t h e vinyl analog. 70
yo
NF- CH=CH- C Z'
"
XI11 XIV xv X V I SR Further work on nitrof'uryl viny168,70 and butadienyl compounds has been reported. 3-hino-6- [ 3 ' -methyl- 4 ' 1( 5-nitro- 2- f'uryl ) but a d i e i y l ] -as- t riazine, t h e butadien 1 analog of X I I , w a s very active i n v i t r o ( C o l i - S t a s . a t 0.03I n 2- d i subst i t u t e d amino- 1,3,h- oxadia zole s the n i t rofurylO.O6mcg/a) 3'-methylbutadienyl compound w a s l e s s a c t i v e than t h e v i n y l analog, and the thiadiazole analog of t h e best (0.8-2mcg/ml) compound w a s l e s s a ~ t i v e . 7 ~ Branching of the butadiene, e s p e c i a l l y with a l k y l s l a r g e r than methyl, decreased a c t i v i t y 7 3 of the 2-R2N-oxadiazoles, a s dld a 2-alkyl or phenyl group on t h e 0xadiazole.7~ 4-Methyl-3-methylthio-5-(5 '-nitro-2'-f'urylvinyl)1,2, h-triazole75 had Coli-Staph. a c t i v i t y a t l-l&cg/ml. A ten-fold increase i n Coli-Staph. a c t i v i t y ( t o l - a c g / k ~ )r ~ e s~u l t e d on c y c l i z a t i o n of t h e acyl semicarbazide t o the 2-amSno-oxadiazole X I I I . The 2-0x0 analog had Coli-Staph. a c t i v i t y a t lmcg/ml while i t s 2-ethoxy and
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2-chloro analogs were much l e s s active. Various 3-acyl-2-0x0 analogs of X I 1 1 were equally active but l e s s t o x i ;77 t h e 3-CH3-2-0x0 analog w a s more act i v e (Coli-Staph. a t O.lmcg/ml) .78 The 3 I-methylbutadlenyl 2-0x0 analog79 shifted i n a n t i b a c t e r i a l spectrum (Staph. 0.4 and Coli 5Omcg/ml). The pyrh i d i n o n e X I V w a s broadly a c t i v e but only a t lO-3Omcg/ml except f r Shigella (0.5mcg/ml) ; cross-resistance with fwazolidone was not observed. 80
I n the 3-(5'-nitro-2'-f'uryl)acryloyl g ou XV, a c t i v i t y w a s poor when Z was pyrazoline, a l k y l or carbethoxyalkyl.fjl,82 When Z was 2-imidazoline, Staph. a c t i v i t y w a s 10s without change i n Coli a c t i v i t y r e l a t i v e t o the simple amide8&8; RH~).'~ When bromine i s present ( Z = CH$r o r NF-CH== C ( Br )- CHO ) the compounds a c t by a d i f f e r e n t mechanism and a r e un table i n vivo t o SH groups. Then Z was " H - d i s u b s t i t u t e d ~ y r i m i d i n y 1 , 7 ~ , ~ ~ Coli-Staph. a c t i v i t y 1" good (lmcg/ml) but not when Z was NH-5-CH2pyrimidinyl-2,4-R2 (lOmcg/ or " H - c e r t a i n a ~ y l s . ~The 7 spectrum of 60 n i t r o f'urans w a s studied:@ classes of compound i n decreasing order of a c t i v i t y
,
)%
NF-CH=N-NH-hetero, NF-CH=N-hetero, IF-hetero, NFa r e NF--CH=CH-Z, C(=NH)--"KR. I n the aldoxime, the aldehyde guanylhydrazone and vinyl- quinoline comparisons89 of Coli-Staph. a c t i v i t y i n vitro, changing 5-nitro- t o 5-methylsulfonyl- f'uryl produced 4- t o 100-fold decreases i n a c t i v i t y , i n contrast t o the same v a r i a t i o n on chlormphenicol. The s u s c e p t i b i l i t y of almost all s t r a i n s of various species of Neisseria (gonorrhoeae, meningitidis, flava) t o i n v i t r o i n h i b i t i o n by acetazo1azni.de (2-acetanino-1 3, bthiadiazole-5-sulfonamide) i s unique r e l a t i v e t o other organisms, go, g i but apparently does not carry over t o i n vivo infections. I n h i b i t i o n of only N. eon. occurred a t high C02 concentrations; the other N. and r e s i s t a n t b a c t e r i a appear t o have low concentrations of carbonic anhyb a s e . 90 A miscellaneous group of a n t i s e p t i c s reported i s mostly reminiscent of known a n t i b a c t e r i a l types : 2-guanidino-6-substituted quinazolines92 vs. Staph. and Salmonella a t lO-lOOmcg/ml; N, N'-di( cyclohexylpropyl)-l, 4-bis (aminmethy1)cyclohexane~~vs. Staph., S t r p., Salm. and Coli a t 3-lOmcg/ml; 3-(p-bromophenyl)-6-brcano-l, 3-benzoxazineg' vs. Salm. and Klebsiella a t 204Omcg/ml; and sodium dodecyldi- (and mono) chlorodiphe loxidesulfonateg5 vs. Staph. a t 5mcg/ml. TI e a c t i v i t y of t h e pyridazinonesg XVI ( R = H and CH3) i s curiously specific: 0.5-3mcg/ml against Shigella species but much l e s s e f f e c t i v e against Coli and Salmonella. Mechanism of Action.-Nalidixic acid I s e l e c t i v e l y i n h i b i t s DNA synthesis i n growing E. c o l i , acting d i r e c t l y against i t s r e ~ l i c a t i o n . 9The ~ bacteric i d a l phase of i t s action can be prevented by i n h i b i t i o n of the synthesis of p r o t e i n (e.g. by chloranrphenicol) o r of RNA. Similarly, the addition of seve r a l , but not a l l , nitrof'urans antagonized i t s i n v i t r o a n t i b a c t e r i a l a c t i v i t y against various Proteus-Providence species, g8 but n a l i d i x i c acid did not oppose the action of the nitroflrrans. The l a t t e r a l s o antagonized i t s a c t i v i t y against Coli and Salmonella s t r a i n s , 99 as did t e t r a c y c l i n e and chloramphenicol against a number of coliform organisms.100 Against B. subt i l i s , one of the few Gram-positive b a c t e r i a susceptible t o it, the mode of action i s a l s o s e l e c t i v e i n h i b i t i o n of DNA synthesis.lol The various hy-potheses on the mechanism of a c t i o n of isoniazid have been reviewed. 102 v a r i e t y of chromatographic Research Techniques And Screening Methods.-A techniques continue t o be applied t o separation and i d e n t i f i c a t i o n of syn-
--
118
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t h e t i c a n t i b a c t e r i a l agents and t h e i r metabolites. G a s chromatogra hy of 60 n i t r o f u r y 1 and n i t r o f l u y l v i n y l heterocycles has been a~complished'~3on a s i l i c o n e column generally without decomposition. Nitrof'urantoin, nitrof'urazone, and f b a z o l i d o n e as well as a l a r g e group of othe nitrofurans were studied i n a v a r i e t y of solvent systems by t h i n - l a y e r l o t and by paperlo? chromatography. About 20 sulfanilamide derivatives have been characterized by t h e i r thinl a y e r chromatographic behavior i n a dozen solvent systems (CHCl ROH mixtures p-dimethylwith or without a t h i r d solvent) usin detection with iodine,l' H ~ ~quantitative ~ u l t r a v i o l e t speca m i n o b e n ~ a l d e h y d e , ~or ~ 7 C U S O ~ - N H ~ O and trophotometry. lo6, 109 A two-dimensional t h i n - l a e r q u a l i t a t i v e method using a basic and an a c i d i c system was a l s o reported.f1o Work c o n t i n u e s l l l on automated analysis of sulfa drug samples (20 per hour) based on the usual diazotization and coupling method; reproducibility f o r therapeutic concentraPaper chromatography of t u b e r c u l o s t a t i c t i o n s was s a t i s f a c t o r y (l-$) agents containing a C = S moiety employed rapid development with methanolwater and detection by means of iodine-azide or mercury-fluorescein reagents.112 D i f f e r e n t i a l thermal analysis has been applied t o the examination of the i d e n t i t y and p u r i t y of ethambutol, s u l f a d r u g s and other synthetic pharmaceuticals. 113 Analog computers were used f o r model calculations on the influence of p r o t e i n b'nding on the clearance of a long-acting b-sulfa-5,6-dimethoxypyri m i d i el1$ and f o r devising optimal therapeutic regimens f o r sulfasymazine N o new a n t i b a c t e r i a l screening methods were reported. Recent success i n experimental animals and i n v i t r o with growing the lepros b a c i l l u s has l e d t o s i g n i f i c a n t and promising additions t o our knowlecige.lf5 Over 100 Myco. leprae s t r a i n s from a l l over the world and from the several c l i n i c a l types of leprosy have now produced mouse foot-pad infections. The r e l a t i o n s h i p of b a c t e r i a l morphology, administration of a n t i l e p r o t i c agents, BCG vaccination, and immune-response suppression t o production of increased infectivi t y i n mice has been studied. The neural involvement produced by t h i s organism i n t h e mouse and hamster i n f e c t i o n s i s unique among the mycobacteria and i s c h a r a c t e r i s t i c of t h e c l i n i c a l disease. Reviews.-The followi have been reviewed: species differences amon ethambutol laboratory and c l i n i c a l studies, $9, drofolate reductases, 'vstructure-activity r e l a t i o n s h i p s i n ethambutol analogs, 32 mode of act i o n of isoniazid,lo2 progress i n l e rosy research,115 lorg-acting s u l f a n i l amides i n urinary t r a c t infections, 48 and i n f e c t i o u s drug resistance. 1 23 39 4
.
.k
8%
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"
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(1965). 91. T. C. Eickhoff, 6 t h I n t e r s c i . Conf. Antimicrobial Agents Chemother.
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p. 1. P. Brown, B r i t i s h patent 1,024,907 (1966). G. Humber, U. S. patent 3,244,750 (1966). Urbanski and J. Venulet, French patent 1,429,328 (1966). F. Steinhauer and J. C. Valenta, U. S. patent 3,252,856 (1966). Takahashi and T. Maki, Japanese patent 103( '66). 97. T\i. H. Dietz, T. M. Cook and W. 2.. Goss, J. Bacteriol. 91, 768 (1966). 98. Y. Kanazawa and T. Kuramata, Jap. J. Bacteriol. 21, 21F(1966). 99. W, S t i l l e and K. H. Ostner, Klin. Wochschr. 44, 3 5 (1966). 100. R. P. Mouton and A. Koelman, Chemotherapia l c 10 (1966). 101. T. M. Cook K. G. Brown, J. V. Boyle and W. A. Goss, J. Bacteriol. 92, 1510 (lg66). 102. J. Nestler, Arzneimittel-Forsch. 16, 1442 (1966). 103. K. Nakamura, Y. Utsui and Y. N i n a y a , Y a k u g a k u Zasshi 86, 404 (1966). 104. R. Neidlein, E. Hohndorf and J. Rosenblath, Pharm. Z t g . Ll l , 874 (1966). 105. V. Cohen, J. Chrcanatog. 23, 446 (1966). 106. M. Sarsunova, V. SchwarzTE. Feketeova and J. Protiva, P h m a z i e 21, 219 (1966). 107. C. H. Pao, Chem. Abstr. 65, 6996g (1966). 108. K. C. Guven and 0. PekinTChem. Abstr. 65, 1992813 (1966). 109. G. Wagner and J. Wandel, Pharmazie 21, 105 (1966). 110. W. Kamp, F'harm. Weekblad 101, 181 (1966). 1ll. H. P. Probst, W. F. Rehm H .Spoerri and J. P. Virilleumier, Chem. Abstr. 64 11,703f (1966). 112. D. G o e c d i t z , Pharmazie 21, 668 (1966). U3. L. M. Brancone and H. J. Errari, Microchem. J. 10, 370 (1966). 114. E. Krueger-Thiemer, Arzneimittel-Forsch. 16, 1 4 3 r (1966). 115. Editors, Chronicle WHO 20, 98 (1966). 116. G. H. Hitchings and J. Burchall, Federation Proc. 25, 881 (1966). 117. N. Y. Acad. Sci. Conference, L m . N. Y. Mad. Sci. 680-939, 107% 1084, 1098- 1u8 ( 1966) 92. J. 93. L. 94. T. 95. A. 96. T.
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c
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ax
122
Chapter 13. Antiviral Agents Ernest C. Herrmann, Jr., Mayo Clinic and Mayo Foundation, Rochester, Minnesota Because it is brief, this review regrettably must exclude certain significant aspects of antiviral research. No attempt will be made to include the substantial basic research on viral inhibition. Perhaps even more serious is the exclusion of papers on interferon and agents that induce interferon (statalon, helenine). It is possible that interferon is the key to a comprehensive approach to the problem of human viral disease but more work must be done to establish that interferon has a role in recovery from such disease in humans. At least one review appeared in 1966.&It is rather unfortunate that the authors' introductory remarks indicate that basic research has now established the feasibility of specific viral inhibitors. Basic research has only confirmed what has been known for well over a decade: that viruses can be inhibited without harm to the host. Perhaps the basic researcher has been slow in capitalizing on early antiviral studies. It is worth noting that virtually all agents presently used in fundamental antiviral studies were discovered in less than a logical manner--in fact, most were products of screening programs. The authors imply that there was logic to the discovery of hydroxybenzylbenzimidazole; actually, this was first observed to be an inhibitor of poliovirus in 1955 in the course of a screening program.*The authors may well have later rediscovered this compound but apparently only after screening a "large number" of benzimidazole derivatives. Such historical reflection seems necessary at times to establish how antiviral agents have been discovered. For the present, perhaps the term "chemotherapy" should be replaced by "antiviral." Few seem clear in their use of the term "chemotherapy" in viral disease. Indeed, in that some of the most interesting antiviral drugs are protective only, the term "chemotherapy" is completely inaccurate. Adamantanes. Amantadine hydrochloride (Symmetrel, EXP lO5), now released by the Food and Drug Administration, has been further examined in double-blind studies in volunteers infected with influenza A2 3 viruswand in epidemics caused by the same virus in adults*and in chilx dren.vThese studies noted no significant toxic reactions despite prolonged dosage schedules. All studies indicate some suppression of antibody response to the infecting virus and a substantial decrease in the number and severity of influenza cases. The drug did not completely suppress the antibody response or the disease. Apparently only one trial
Chap. 13
Her rmann
Antivirals
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5
included attempts to isolate the virus.-Although there has not been a high degree of success in using virus shedding as a parameter in this type of clinical trial, there was considerable success with this technique in an experiment with horses infected with influenza A/EQUINE 2 virus.& Only three of seven horses treated with amantadine briefly shed virus while all seven untreated animals shed virus for 8 days. Drug-treated horses had a decreased i m n e response but it was thought that they were immune to rechallenge with the same virus. There has been some concern that a highly active prophylactic agent might prevent development of natural immunity. However, even if this is a genuine problem, amantadine is clearly not sufficiently potent. In mice infected with an adequate dose of virus, amantadine suppressed but did not eliminate the specific antibody response.& Amantadine apparently does not have an effect on antibody response in general. One reportwndicates that amantadine, ammonium ion, and caprochlorone may have the same mode of action: they inhibit penetration of influenza virus into the cell. This further emphasizes the usefulness of drug research in exposing a previously little known aspect of cell-virus interaction. There remains, however, a continuing problem of quantitation in comparative studies of antiviral agents. There is no general agreement on which tests are valid in demonstrating an antiviral effect and which tests produce reliable quantitative data. Some effort is being made to study the proper experimental design in tests with mouse influenza and amantadhe.* Still another in-vitro antiviral test, a copy of the gradient-plate method used in antibacterial studies, has been described. Both amantadine and rimantadine hydrochloride (EXP 126, amethyl-1-adamantanemethylamine HC1) were given to children during an epidemic caused by measles and influenza B viruses.* No beneficial results were observed, which is not surprising because these two viruses are not very sensitive to these drugs but it is of interest that rimantadine is being tested clinically. This compound is about eight-fold less toxic in embryonated chicken eggs than is amantadine, but it may be slightly more toxic in mice.* In mouse experiments rimantadine is quantitatively superior to amantadine against influenza A virus infections, and it showed stronger therapeutic effect. More than 1,200 humans have received the /3 Preliminary drug and it appears to be better tolerated than amantadine.b clinical trials indicate that rimantidine is active in protecting against influenza Ag virus disease. N-Methyl-1-adamantanecarboxamide octochloro chlorination product was r e p o r t e d w t o have a remarkable curative effect in mice infected intracerebrally with lethal doses of neurotropic influenza A/WSN virus. Even if treatment is withheld until the mice show tremors and paralysis, they can still be saved; however, this drug has no effect on pulmonary influenza virus infections in mice. Whatever its use, this drug certainly manifests a true chemotherapeutic action.
*
Sect. 111
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- Chemotherapeutics
Cheney, Ed.
It is only fair to point out that, with protective drugs active against only certain strains of influenza virus, there are substantial logistic problems. Before amantadine can be used, there must be timely laboratory diagnosis indicating that a community is under attack by a virus which is sensitive to the drug. Few physicians are in a position to obtain such timely information. Suggestions have been made on how the entire problem of more rapid laboratory diagnosis might be approached.- /5 Thiosemicarbazones. A number of reports on the use of methisazone (N-methylisatin-B-thiosemicarbazone, marboran, 33T57) appeared in 1966. This drug was found to be beneficial in vaccinia gangrenosay& ineffective in chickenpoenot surprising] , rather effective in protecting humans against variola minor (alastrim),&beneficial in malignant lymphoif confirmed, would be remarkable], perhaps useful in ma in man&[which, children given smallpox vaccine when it is contraindicated,*benef icial aJ and inadequately tested in a in a serious case of eczema vaccinatumk unique case of cowpox.* In virtually all these clinical trials there was a substantial amount of nausea and vomiting. Even with this troublesome reaction it would seem wise to have the drug available in the United States for use in the occasional smallpox vaccine reactions, which are often fatal, and the rare smallpox scares. On the basis of development of resistance to methisazone by rabbitpox virus in tissue culture and in rabbits, the possibility of this problem also occurring in the use of this drug in smallpox was suggested.* As shown in many antibacterial studies, in-vitro induction of resistance does not necessarily have clinical implications. There is some question whether use of this drug will ever become so extensive that drug resistance could occur. During 1966, two reports appeared on test methods for thiosemicarbazones, one involving vaccinal tail lesions in the mouse and the other a combined use of anticonvulsants with antiviral compounds to control vaccinia virus infections in mouse brain.* Inhibition of adenovirus 11 by methisazone-ame as a surprise; however, the virus dose used was extremely small and it was found, by other test methods,that methisazone did not affect plaque formation of adenoviruses 1, 2, and 5 . S T h e s e same methods did reveal that methisazone produced considerable toxicity in HeLa cells, the type of cell used in the original study. It is possible that the antiviral action observed was due to a toxic reaction not readily observed in the test system used. Extensive clinical trials were made with isothiazole thiosemicarbazone (4-bromo-3-methyl-isothiazole-~-carboxaldehydethiosemicarbazone, M 8c B 7714) which, although very active in animal tests, has virtually no activity against smallpox either therapeutically or prophylactically. Again vomiting was a common reaction, and this drug also produces an unconjugated hyperbilirubinemia in humans, which has now been studied in rabbits
*
.*
Chap. 1 3
Antivirals
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Nucleosides. Apparently 5-iodo-2'-deoxyuridine (IUdR, idoxuridine) has become a standard drug for treatment of herpetic eye infections. The most recent report of its effectiveness in this disease involved 1,202 human cases.&There has been some concern about IUdR inhibiting corneal healing; it now appears that, in herpes simplex infected eyes, corneal healing is not r e d u c e d . m u r t h e r studies in hamsters have also reconfirmed the therapeutic effectiveness of this drug.* Some very encouraging results have been obtained in the treatment of dermal herpetic lesions in man with IUdR.L3)Z,If the drug was dissolved in dimethylsulfoxide (DMSO) it was especially active; indeed, DMSO alone seemed to be beneficial. Both of these studies were well controlled, and in one of them both virus isolation and serologic tests were used to confirm the diagnosis. Early use of the drug on the involved tissue is essential. Because herpes simplex virus i s sensitive to many compounds, the treatment of dermal herpes seems long overdue. The Upjohn Company has been pursuing such a clinical trial using the antiherpetic compound cytosine arabinoside (cytarabine, CA).\2& It has been claimed that cytarabine has some toxicity in the cornea when used in herpes keratitis; however, a recent report indicates that this so-called toxicity is essential to the antiviral effect of the drug.eThere is also a report of successful treatment of a single case of vaccinia1 blepharokeratitis\ith cytarabine. There have been a number of reports on the inhibition in tissue culture of DNA-containing adenoviruses by cytarabine.*With other test m e t h o d s w i t was found that DNA inhibitors, such as IUdR, BUdR, and CUdR, were not highly active against adenoviruses 1, 2, and 5, and this is true also of cytarabine which was much more toxic than the r e s t m o m e antiviral activity could be demonstrated, especially with CUdR, but it was not remotely comparable to that seen with herpes simplex and vaccinia viruses. It has been surprising that DNA-containing adenoviruses seem to be resistant to such inhibitors IUdR was found to be active against infectious bovine rhinotracheitis virus in cell culture but there was some doubt about activity in r a b b i t s . ~ T r i f l u o r o t h y m i d i n e seemed to be more effective than IUdR in herpetic corneal lesions in rabbit eyes , w w h i l e the antiherpetic compound methylaminodeoxyuridine was less effective than IUdR in the same study In cell culture studies, 6-azauridine was much less active than IUdR against vaccinia virus , d n a @ azathymidine and uracil methyl sulphone were less active against herpes simplex virus . ~ - ~ y c l o p e n t y l - 6 - m e r c a p topurine was claimed to be active against Friend leukemia virus in v i v 0 . a Of interest is the antiviral effect found for N6 (2-hydroxyethyl)-adenine in mice infected with Coe virus (coxsackie A-21).&'Although this is not a typical common cold virus, it does produce colds in human volunteers (there has been a study of the effect of this drug in such volunteers but
.
.*
Sect. 111 - Chemotherapeutic s
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Cheney, Ed.
the details have not been published). In mouse studies, antiviral effects were observed with one tenth the lethal dose of the drug. Drug toxicity could be suppressed by xanthine oxidase inhibitors which did not influence the antiviral action. It is significant thzt both animal and human trials can be used to study inhibition of this virus, Other antiviral agents of interest. There have been reports of antiviral agents active in laboratory tests and it is not easy to determine which of these, if any, might lead to a useful drug. Some investigators may still be confusing toxic effects on the host with true antiviral action. Despite this, antiviral studies have made commendable progress from the original concept that specific viral inhibition was not possible A further report has been made on phagicin, a protein material from phage-infected Escherichia that has shown antiviral effects against vaccinia and herpes simplex infections of the eye.*Apparently this protein i s a poor antigen. Hydroxyurea is an inhibitor of DNA synthesis in a number of biologic systems, including those of vaccinia and herpes simplex viruses. Because viral protein synthesis appears to be unaffected, the authors suggest this might make a useful drug that would not influence specific immune response. This seems a little premature in the absence of substantial proof of activity in vivo. In further studies of plant antiviral substances it was found that a number of extracts had activity against influenza virus in cell cultures and in mice.eInfluenza A virus appeared to be inhibited in mice treated with l-(~-fluorophenyl)-l-phenyl-2-propynl-N-cyclohexylcarbamate ( F P C v a n d 2-diethylaminoethyl-~-methylpiperazine-l-carboxy l a t e5 .5w h e latter compound, when studied in cell culture, appeared to have a mode of action much like that of amantadine.*Compounds that stimulate mucus production (cholinergic compounds) made influenza A virus infection in mice more severe while anticholinergic drugs made the disease less severe.0The concept of using pharmacologically active drugs rather than specific antiviral agents has some merit and certainly requires further exploration, especially for the problem of the common cold. Viractin, a distillate from Streptomyces griseus, has been claimed to protect humans from respiratory virus disease. It was found, however, that the material had no in-vitro or in-vivo activity in tests against a variety of respiratory v i r u s e s . e A note appended to this report is highly critical because apparent1 no claim was made for activity Salmoexcept in humans. Products from 2. s&ropionibacteria,*nd nella t y p h o s a w a v e produced interesting antiviral effects. It must be said, however, that the search for antiviral antibiotics is still in its infancy. Among a host of other papers on antiviral effects is one reporting that huge doses of the plasma expander, polyvinylpyrrolidone, inhibited vaccinia and herpes simplex viruses in cell cultures$%ubstituted
.
Chap. 1 3
An ti vi ral s
H e r rmann
127
morpholonium quaternary compounds have been shown to be active in mice infected with mouse hepatitis and herpes simplex viruses.*n cell culture, N1-furfurylbiquanide was active against a variety of RNA viruses.* A lengthy report on the effect of salicylates on EMC virus in cell culture b5 is not completely convincing-certain derivatFves of 4-0x0- 5-thiazolidine are claimed to have a wide antiviral spectrum but only data for poliovirus inhibition are presented.* B a u e r w a s made an interesting suggestion in attempting to relate virus size to the effectiveness of antiviral agents. It i s perhaps somewhat early in the history of the search for antiviral drugs to draw too many conclusions from the presently known antiviral substances. One wonders what the conclusions would have been if a few dozen other known antiviral agents had been incorporated in Bauer's study. Various pharmaceutical companies still have a number of agents not yet reported in the literature; for example, Smith Kline & French Laboratories has a compound or compounds highly active against a number of rhinoviruses in cell culture systems.@'Without information on a number of such compounds, analysis at this time seems premature. An interesting and comprehensive study of compounds that release cyanate in vivo, resulting in antiviral effects only against pseudorabies virus,w l u s t r a t e s the fundamental discoveries resulting from studies of agents uncovered in a screening program. A close look at the products of screening programs could convince one that, although these programs have been the sole source of antiviral drugs so far, they in fact also may have been even more productive in basic research.
128 -
Sect. I11
- Chemotherapeutic s
Cheney, Ed.
References 1. H. J. Eggers and I. T a m , Ann. Rev. Pharmacol., 6,231(1966). 2. A. C. Hollinshead and P. K. Smith, J. Pharmacol. Exptl. Therap.,
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J. F. Webber, R. Marks and T. A. G. Reed, Brit. J. Dermatol.,
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22. W. F. T. McMath and H.)T. H. Wilson, Brit. Med. J., 1,lOhl(1965). 23 G. Appleyard and H. J. Way, Brit. J. Exptl. Pathol., Q, 144(1966). 24. J. J. Boyle, R. F. Haff and R. C. Stewart, Abstracts of papers, Sixth
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M. Lieberman, R. Pollikoff and A. Pascale, Abstracts of papers, Sixth Interscience Conference on Antimicrobial Agents and Chemotherapy, P. 33(1966). 26. D. J. Bauer and K. Apostolov, Science, 796(1966). 27. E. C. Herrmann, Jr., J. Gabliks, C. Engle and P. L. Perlman, Proc Soc. Exptl. Biol. Med., 3,625(1960). 28. E. C. Herrmann, Jr., Unpublished observations. A. R. Rao, J. A. McFadzean and K. Kamalakshi, Lancet, I,1068(1966). 29 30. A. R. Rao, G. D. W. McKendrick, L. Velayudhan and K. Kamalakshi, Lancet, 1,1072(1966). 31. T. Hargreaves, Nature, 210, 639(1966). 42(1965). 32. E. Maxwell, Am. J. Ophthalmol., 33 C. Hanna, Am. J. Ophthalmol., 6l, 279(1966). 183(1966). 34. H. Schumacher and R. Machemer, Ophthalmalogica, R. W. Sidwell, S. M. Sellers and G . J. Dixon, Abstracts of papers, 35. Sixth Interscience Conference on Antimicrobial Agents and Chemotherapy, p. 29( 1966). 36 M. B. Corbett, C. M. Side11 and M. Zimmerman, J. Am. Med. Assoc., 25
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z,
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F. 0 . MacCallum and B. E. Juel-Jensen, Brit. Med. J., 2, 805(1966). D. A. Buthala, Personal communication to the author. D. A. Buthala, G. A. Elliott and G. E. Underwood, Am. Soc. Microbiol., Bacteriol. Proc., p. 114(1966). 40. D. M. Gordon and S. Advocate, Am. J. Ophthalmol., 2, 480(1965). 41. L. A. Feldman and F. Rapp, Proc. Soc. Exptl. Biol. Med., 122, 243 ( 1966 1. 116(1966). 42. A. Persechino and Z. Orfel, Arch. Ges. Virusforsch., 43. R. A. Hyndiuk and H. E. Kaufman, Invest. Ophthalmol., 2 , 424(1966). 44. T. Y. Shen, J. F. McPherson and B. 0 . Linn, J. Med. Chem., 9, 366
37 38. 39
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B. Rada and D. BlaYskovi;, Acta Virol., Q, i(1966). 46. L. Sekely and W. H. Prusoff, Nature, 211, 1260(1966). 47. R. W. Sidwell, P. Compton and G. J. Dixon, Am. Soc. Microbiol.,
45
Bacteriol. Proc., p. 114(1966). 48. G. E. Underwood, C. A. Baker and S. D. Weed, Proc. Soc. Exptl. Biol. Med., 122, 167(1966). 49 Y. M. Centifanto, Am. Soc. Microbiol., Bacteriol. Proc., p. 113 ( 1966 1.
50
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51.
H. M. Rose, H. S. Rosenkranz, C. Morgan and K. C. Hsu, Federation Proc., 3,311( 1966). S. Nit, C. Morgan, H. M. Rose and H. S. Rosenkranz, Federation Proc.,
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53
H. S. Rosenkranz, H. M. Rose, C. Morgan and K. C. Hsu, Virology,
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K. W. Cochran, T. Nishikawa and E. S . Beneke, Abstracts of papers,
Sect. 111 - Chemotherapeutics
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54 55.
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S i x t h I n t e r s c i e n c e Conference on Antimicrobial Agents and Chemotherapy, p. 32( 1966) D. C. DeLong, R. D. D i l l a r d , N. R. Easton, F. S t r e i g h t o f f , W. S . Bonieca and C. E. Redman, Abstracts of papers, S i x t h I n t e r s c i e n c e Conference on Antimicrobial Agents and Chemotherapy, p. 32(1966). H. F. Lindh and M. Forbes, Proc. SOC. Exptl. Biol. Med., 121,65
( 1966 )
56.
57
9
58 59 60.
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R. D. F l e t c h e r , J. E. H i r s c h f i e l d and M. Forbes, Proc. SOC. Exptl. Biol. Med., 121, 68(1966), F. S t r e i g h t o f f , C. E. Redman and D. C. DeLong, Abstracts of papers, S i x t h I n t e r s c i e n c e Conference on Antimicrobial Agents and Chemotherapy, p. 31( 1966). D. A. J. T y r r e l l and G. H. Walker, Nature, 210, 386(1966). J. Vilzek and J. H. F r e e r , J. Bacteriol., 92, 1716(1966). S . Ramanathan, G. W. Read and W. Cutting, Federation Proc., 3, 562( 1966). H. Hades, Cited i n A n t i b i o t i c News, 2 , Oct. 9, 1966. B. S . Michaels, G. H. Waddell, D. D. Zinner and M. M. S i g e l , Nature,
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E. L. Anderson, J. E. Casey, Jr., E. E. Force, E. J. Jensen and R. S. Matz, J. Med. Chem., 9, 211(1966). Y. Schimizu, A. Tsunoda and N. I s h i d a , Proc. SOC. Exptl. B i o l . Med.,
B, 488( 1966). 65.
A. D.
I n g l o t , M. Kochman and P. Mastalerz, Acta Virol.,
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67 68. 69
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P. Schauer, M. Likar, M. T i g l e r and A. Krbavziz, Pathol. Microbiol., 2,506(1966)* D. J. Bauer, Nature, 209, 639(1966). V. V. Hamparian, Personal communication t o t h e author. R. B. Grunert, W, L. Davies, J. W. McGahen, C. E. Hoffmann and R. A. Yates, J. I n f e c t . Diseases, &, 346(1966). R. A. Yates and R. R. Grunert, J. I n f e c t . Diseases, G,353(1966).
Chapter 14a. Human A n t i p a r a s i t i c Agents Edward F. E l s l a g e r , Parke, Davis and Co., Ann Arbor, Mich.
INTRODUCTION - B e t t e r drugs a r e s t i l l needed f o r t h e treatment of many chronic and d e b i l i t a t i n g human -p a r a s i t i c d i s e a s e s , i n c l u d i n g schistosomias i s , f i l a r i a s i s , Chagas' d i s e a s e , l e i s h m a n i a s i s , t r i c h u r i a s i s , and strongyl o i d i a s i s . Moreover, a r e a p p r a i s a l of t h e s t a t u s of malaria chemotherapy (1)t h e urgent need f o r developing new f a s t - a c t i n g suppreshas i n d i c a t e d : s i v e agents e f f e c t i v e a g a i n s t d r u g - r e s i s t a n t plasmodia j (2:) t h e p o t e n t i a l usefulness of long-acting drugs, p a r t i c u l a r l y i n malaria e r a d i c a t i o n programs; and ( 3 ) t h e importance of developing s a f e and e f f e c t i v e a n t i - r e l a p s e drugs capable of e f f e c t i n g a r a d i c a l cure i n a s i n g l e dose o r , a t most, i n a three-day regimen. During t h e p a s t year s i g n i f i c a n t progress was made i n man's continuing s t r u g g l e against, p a r a s i t i c d i s e a s e s . I n t h e discussion t h a t follows, f r e q u e n t r e f e r e n c e i s made t o r e c e n t review^"^ t h a t provide background information on broad a s p e c t s of p a r a s i t e chemotherapy. W
I
A
-
Several reviews have r e c e n t l y been published.',
3,5-8
(a) ( - The problems posed by t h e e x i s t e n c e of d r u g - r e s i s t a n t s t r a i n s of falciparum malaria have spurr e d e f f o r t s t o develop b e t t e r experimental models f o r studying t h i s phenomenon. A s reviewed elsewhere, 5 9 s t r a i n s of avian, murine, and/or simian p a r a s i t e s have been induced t o a c q u i r e r e s i s t a n c e t o r e p r e s e n t a t i v e s of a l l t h e major c l a s s e s of a n t i m a l a r i a l drugs, and t h e r e s i s t a n t l i n e s have been employed i n c r o s s - r e s i s t a n c e s t u d i e s t o determine t h e i n t e r r e l a t i o n s h i p among t h e various chemical t y p e s .3,5,10-15 R e s u l t s from t h e s e experiments provide a b e t t e r r a t i o n a l e f o r s e l e c t i n g a l t e r n a t i v e drugs f o r use a g a i n s t d r u g - r e s i s t a n t p a r a s i t e s , and a f f o r d a b a s i s f o r recognizing compounds with a novel mode of a c t i o n . ( b ) Mode of Action of A n t i m a l a r i a l Drugs - It i s g e n e r a l l y assumed t h a t a n t i m b y i n h i b i t i n g e s s e n t i a l enzymatic r e a c t i o n s i n t h e a f f e c t e d microorganism i t s e l f . Among i n t r a c e l l u l a r organi s m s such a s m a l a r i a l p a r a s i t e s , however, t h e p o s s i b i l i t y e x i s t s t h a t t h e agent i n h i b i t s an enzymatic r e a c t i o n of t h e h o s t c e l l t h a t produces a product e s s e n t i a l t o t h e p a r a s i t e . The l a t t e r mechanism i s apparently involved i n t h e a c t i o n of a n t i - p a n t o t h e n a t e s a g a i n s t Plasmodium lopliurae. This paras i t e , which r e q u i r e s an e x t e r n a l source of coenzyme A ( C o A l X i n h i b i t e d by anti-pantothenate (SN-14,622) when it i s developing i n t : r a c e l l u l a r l y , b u t not when it i s c u l t u r e d e x t r a c e l l u l a r l y i n v i t r o .16 The a n t i - p a n t o t h e n a t e presumably i n t e r f e r e s with a r e d - c e l l system s y n t h e s i z i n g CoA, thereby dep r i v i n g t h e p a r a s i t e of an adequate source of CoA.
A r e c e n t comparison of t h e a c t i o n of chloroquine, quinacriine, pyrimethamine, and s u l f a d i a z i n e on 2. lophurae developing i n t r a c e l l u l a r l y o r e x t r a c e l l u l a r l y i n v i t r o showed t h a t each drug had t h e expected i n h i b i t o r y e f f e c t on
Sect. 111 - Chemotherapeutics
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parasites developing within their host erythrocytes, but that none inhibited the development of extracellular parasites at the same concentration^.'^ Assuming that parasite integrity is maintained, one explanation would assume that certain drugs are concentrated in the red cells so that parasites within the cells are actually exposed to much higher concentrations than were used in the medium. This explanation is plausible with regard to chloroquine; for recent studies” suggest that chloroquine is selectively toxic because it attains higher concentrations in parasitized red cells than in normal erythrocytes, and that resistance is due to an impairment of the mechanism by which such drug levels are accumulated. A second explanation is based by analogy on the proposed mechanism of action of the anti-pantothenates, and would assume interference by the drug with a host cellenzyme system that supplies a product required by the parasite .I7 A number of considerations place 2. berghei in the class of microorganisms that are dependent on endogenous synthesis for folate-containing cofact ~ r ~ . ~ ~ experiments , ~ ~ Recent show that 2. berghei can convert dihydrofolate (FHz), but not folate, to materials capable of satisfying the growth requirements of Pediococcus cerevisiae, and therefore presumably cofactor forms of tetrahydrofolate (FH4).20 This shows that cells of 2. berghei are capable of folate cofactor biosynthesis and do not have to depend on the host erythrocytes for this function. The utilization of F H 2 required NADPH and was inhibited by pyrimethamine,” which suggests the presence of FH2 reductase in these parasites .20
-
(c) Suppressive Antimalarial Drugs
(1)Sulfones and Sulfonamides, either singly or in combination with pyrimethamine, are of considerable interest as possible alternative drugs for oral suppressive use against drug-resistant 2. falciparwn. Among them, diaphenylsulf’one (DDS)(Ia), conventional sulfonamides such as sulfadiazine, and the long-acting congeners sulforthomidine ( IIa ), sulfamethoxypyridazine (ID) , sulfapyrazinemethoxine ( IIc), and sulfadimethoxine (IId) have been e v a l ~ a t e d . ~ In ~ ~man, ~ ~ ~response ’ ~ ~ to these drugs is characterized by
NH2
NHFi
SO2
Het
=
a, H NH i
Het NHR
OCH3
I
I1
relatively slow antimalarial action,5~21-24 greater efficacy against g. f a l ~ i p a r u m ~ ’ -than ~ ~ 2. vivax,26 suppressive action against multi-resistant
Chap. 14a
A n t i p a r a s i t i c s , Human
El s l a g e r
133 -
P. f a l ~ i p a r u m , ~ ~and , ~good ~ , ~ tolerance.21-27 ~ The daily administration of 25 mg of DDS concurrently with 300 mg of chloroquine base and 45 mg of primaquine weekly proved highly effective in preventing patency following challenges with two strains of chloroquine-resistant 2. falciparum. The sulfone-sulfonamide group acts at a different site than cycloguanil (IX) or pyrimethamine, presumably by preventing the incorporation of 2aminobenzoic acid into folic acid. Utilization of the two types in combination enhances antimalarial activity in experimental infections3~5,15 and in man,3,22,26 affords broad action against resistant organism^,^,^,^^ and decreases the likelihood of the emergence of resistance."J5 There is undoubtedly a need for further assessment of the antimalarial value of s u l fones and sulfonamides, both alone and in combination with other agents. Because of known deficiencies, however, they are not likely to provide the final solution to the problem of treating drug-resistant malarias.
-
( 2 ) 4-Aminoquinolines Earlier reports3, 28 that I11 was active against chloroquine-resistant 2. berghei were surprising, since the chloroquineresistant strains studied to date have proved uniformly cross-resistant to other 4-aminoquinolines and to 9-aminoacridines 5~ However, recent studies utilizing a different chloroquine-resistant strain of 2. ber hei showed a high degree of cross-resistance between I11 and c h l o r o g u i n e ~ m i I a r l y ,
.
111 12,278 R.P.
rv
IV and relatives exhibited potent activity against normal P. berghei, but were ineffective against a chloroquine-resistant strain.
( 3 ) Potential Antimetabolites - Several new types are reported to be active against drug-resistant malarial parasites in experimental animals. Tetrahydrohomopteroic acid (Val was effective against both normal and pyrimethamine-resistant _P. cynomolgi in monkeys,31 but tetrahydrohomofolic acid (Vb)
R
=
a, OH; b, NHCH(C02H)(CH2)2C02H
V
VI
S e c t . 111 - C h e m o t h e r a p e u t i c s
134 NH-alk-NR1R2
Cheney, Ed.
RiRSN-alk-NH
CC13
VII
VIII
Hetol@
was i n a c t i v e .31 A c t i v i t y was a l s o r e p o r t e d among c e r t a i n 2,4,7-triamino-6p h e n y l p t e r i d i n e s ,32 2,4-diaminoquinazolines ( V I ) B 3 and b i s (2,4-diaminopyrimi d i n e s ) ( V I I ) 34
.
(4) Otherw&ents - P r ~ d i g i o s i n 1-aminocyclopentane ,~~ carboxylic acid,36 end Hetol (VIII)36 are e f f e c t i v e a g a i n s t 2. berghei i n mice. HetolB i s also a c t i v e a g a i n s t 2. cynomolgi and 2. knowlesi i n t h e monkey.36
(a) R
e
-_ry
p
o
s
i
t
o
m
(1)Dihydrotriazine and mrimethamine S a l t s - A s i n g l e 5 mg/kg I.M. dose of cycloguanil pamoate (Carnola#) (IX) p r o t e c t s man for many months a g a i n s t challenges with s u s c e p t i b l e s t r a i n s of 2. falciparum or 2. vivax.3?37~38 Urinary e x c r e t i o n s t u d i e s i n human volunteers i n d i c a t e t h a t p r o t e c t i o n i s maintained u n t i l t h e d a i l y cycloguanil e x c r e t i o n r a t e decreases t o 0.25 mg or l e s s , u s u a l l y f o r 8-9 months.38 I n accord with t h e o r e t i c a l expectations, t h e drug w a s i n e f f e c t i v e a g a i n s t p a r a s i t e s known t o be highly r e s i s t a n t t o Cycloguanil pamoate i s u s e f u l , howchlorguanide, pyrimethamine, or b o t h . e v e r , a g a i n s t p a r t i a l l y r e s i s t a n t s t r a i n s , although t h e p r o t e c t i o n p e r i o d is ~hortened.~’’~ ~r t h e r , coadministration of amodiaquine with cycloFu g u a n i l pamoate prolonged t h e period of p r o t e c t i o n i n a r e a s where p a r a s i t e s have some degree of r e s i s t a n c e t o chlorguanide or pyrimethamine b u t a r e s e n s i t i v e t o t h e 4-aminoquinolines .41 Cycloguanil pamoate was w e l l t o l e r a t e d with r e s p e c t t o systemic t o x i c i t y and provoked only mild t o moderate l o c a l r e a c t i o n s a t t h e i n j e c t i o n s i t e when i n j e c t e d p r ~ p e r l y . ~ J ~ ~ - ~ ’
NHCOCH3
M
Cycloguanil
X
CH3COhH
PAM-1503
XI
RC-12
( 2 ) Sulfones - P o t e n t i a l long-acting sulfone and sulfonamide d e r i v a t i v e s have been s y n t h e ~ i z e d ~ t ,o~provide ~ , ~ ~ substances t h a t (1)i n combination
Chap. 14a
A n t i p a r a s i t i c s, H u m a n
Elslager
135 -
with cycloguanil pamoate o r r e l a t e d corn pound^^^ 44 might enable a s e q u e n t i a l block i n t h e metabolic pathway and a f f o r d broader r e p o s i t o r y a c t i o n a g a i n s t d r u g - r e s i s t a n t l i n e s t h a n e i t h e r drug alone, and ( 2 ) may be p a r t i c u l a r l y convenient i n t h e treatment and prophylaxis of Among them, DADDS (Ib) has been s t u d i e d most e x t e n s i v e l y . A s i n g l e paren-ceral dose of DADDS p r o t e c t e d mice f o r many weeks a g a i n s t challenges with 2. berghei and monkeys f o r many months a g a i n s t challenges with _P. cynomolgi t r o p h o z o i t e s o r s p o r o z o i t e s .3J42,46 CI-564, a mixture of cycloguanil pamoate and DADDS, showed b e t t e r a c t i v i t y t h a n e i t h e r component alone a g a i n s t d r u g - r e s i s t a n t plasmodia i n and i n man.40
~ six other repository The d u r a t i o n of a c t i o n of PAM-1503 ( c 1 - 6 0 8 ) ( x ) ~and sulfones a g a i n s t g. berghei i n mice was i n t e r m e d i a t e between t h e s h o r t a c t i n g DDS and t h e very long-acting DADDS.47 Generally, t h e p a t t e r n of u r i n a r y e x c r e t i o n i n r a t s a l s o w as intermediate between t h a t of DDS and While a d d i t i o n a l work may be needed t o a s s e s s t h e b e s t form and amount of r e p o s i t o r y sulfone f o r use with cycloguanil pamoate, t h e potent i a l a n t i m a l a r i a l value of such a combination has been d e m ~ n s t r a t e d ? , * ’ ~ ~ ’ ~ ~ F u r t h e r , each of t h e s e compounds, t o g e t h e r with DADDS, completely suppressed I Q c o b a c t e r i m l e p r a e i n f e c t i o n s i n mice when given i n s i n g l e p a r e n t e r a l doses a t 2-month i n t e r v a l s .45 ( e ) Radical Curative Agents - RC-12 ( X I ) has s u b s t a n t i a l a c t i v i t y a g a i n s t t h e p r e e r y t h r o c y t i c forms of 2. cynomolgi i n t h e monkey b u t shows l i t t l e promise a s a s c h i z o n t i c i d a l o r suppressive agent.48 No r e p o r t s have y e t appeared concerning i t s e f f i c a c y and t o l e r a n c e i n man. Related compounds have r e c e n t l y been d e ~ c r i b e d . ~ ’
LEISHMANIASIS - Leishmania i s r e s p o n s i b l e for m i l l i o n s of smoldering u l c e r s among i n h a b i t a n t s of endemic regions i n A f r i c a , t h e .Americas, and t h e Near and Far East. Recent s t u d i e s have confirmed e a r l i e r r e p o r t s 3 t h a t t h e r e p o s i t o r y a n t i m a l a r i a l drug cycloguanil pamoate (IX) ( s u r a ) shows promise i n t h e treatment of cutaneous l e i s h m a n i a s i s . Thus, 63 of 3 p a t i e n t s i n f e c t e d with Leishmania mexicanum were cured with a s i n g l e dose of cyclog u a n i l pamoate, i n c l u d i n g some s u b j e c t s with a condition of more t h a n 20 y e a r s ’ d ~ ~ . r a t i o An n ~e~f f~e c t i v e r e p o s i t o r y drug wou-ld have important advantages over previous methods of treatment s i n c e dermal l e i s h m a n i a s i s occurs mainly among people i n remote a r e a s .
-E-8
Several o t h e r compounds have r e c e n t l y been r e p o r t e d t o be e f f e c t i v e a g a i n s t l e i s h m a n i a s i s i n experimental animals and i n man, i n c l u d i n g monomycin, 51 paromomycin, 51 dehydroemetine, 52 and
[email protected] CHAGAS’ DISEASE - A t l e a s t 7 m i l l i o n persons i n South a:id Central America a r e i n f e c t e d with Trgpanosoma c r u z i , t h e c a u s a t i v e agent of Chagas’ d i s e a s e . I n c o n t r a s t t o t h e s u c c e s s f u l development of e f f e c t i v e drugs f o r t h e African trypanosomiases,’ t h e treatment of c r u z i i n f e c t i o n s has been g e n e r a l l y u n s a t i s f a c t o r y . There i s evidence t h a t n i t r o f u r a i l s may be e f f e c t i v e a g a i n s t a c u t e i n f e c t i o n s , b u t no adequate c u r a t i v e agent ha; been fownd.3~ 5
Sect. 111 - Chemotherapeutic s
136 -
Cheney, Ed.
No new information i s a v a i l a b l e concerning t h e u s e f u l n e s s of piperamide against cruzi infections. Certain piperidine r e l a t i v e s maleate ( X I 1 ) -
r.
XI1
Piperamide
XI11
( X I I I ) a r e a l s o e f f e c t i v e . 5 5 Other compounds r e c e n t l y r e p o r t e d t o show acc r u z i i n vivo include amphotericin B, emetine, isoquinot i v i t y against line-1-carboxaldehyde thiosemicarbazone, metronidazole (XIV), actinomycin D, and c e r t a i n d i - and triaminotriphenylmethane dyes;56J57 2,&-diarninoquin~ ~ quinazoline d e r i v a t i v e s of a s p a r t i c and glutamic a z o l i n e s ( 1 ~ 1 1 ; and a c i d s . 58 Actinomycin D, mitomycin C, and f l u o r o u r a c i l deoxyriboside i n h i b i t t h e growth of 2. c r u z i i n v i t r o by i n t e r f e r i n g with t h e s y n t h e s i s of prot e i n s and n u c l e i c a c i d s by t h e f l a g e l l a t e . 5 9 Furadantin sodium and NF-902 show e a r l y , marked a c t i o n a g a i n s t i n t r a c e l l u l a r forms of 2. c r u z i i n chick embryo t i s s u e c u l t u r e . 6o
r.
TRICHOMONIASIS - No p a r a s i t i c i n f e c t i o n i s a s common among women of t h e temperate zones a s v a g i n a l trichomoniasis. ( a ) Nitroimidazoles - Metronidazole (FlagylB) ( X I V ) e x h i b i t s broad a n t i p r o t o z o a l a c t i v i t y and i n p a r t i c u l a r has found widespread use i n t h e o r a l treatment of trichomoniasis The metabolism of metronidazole i n t h e dog and i n man i s similar.61 I n both s p e c i e s , t h e u r i n e contained 61-69% of unchanged metronidazole, t o g e t h e r with smaller amounts of t h e corresponding a c i d (26-28%) and a second metabolite which was t e n t a t i v e l y i d e n t i f i e d a s t h e e t h e r glucuronide ( 5 - l l k ) . The a u t h o r s found no evidence t h a t t h e n i t r o group had been reduced. The s y n t h e s i s of novel nitroimidazole cornpounds a s p o t e n t i a l a n t i p r o t o z o a l agents continues a t a dizzying pace, 62-70 b u t none has y e t been demonstrated t o be s u p e r i o r t o metronidazole a g a i n s t t r i c h o nioniasis i n experimental animals or i n man.
I
CH2CH20H XIV
Metronidazole
0
XV
Niridazole
CH2CH2OH
XVI
15,960 R.P.
(b) Other n i t r o h e t e r o c c l i c compounds possess antitrichomonal a c t i v i t y , i n e l l s ,71 n i t r o f u r a n s ,72-74 n i t r o p y r ro1es,75J76 n i t r ~ t h i o p h e n e s , ~ and ~ ' n~i ~ t r o p y r a z o l e s .78 Among them, 15,960 R.P. ( X V I ) i s of p a r t i c u l a r i n t e r e s t . When given orally t o mice, 15,960 R . P . was equi-active with metronidazole a g a i n s t Trichomonas v a g i n a l i s and n e a r l y t e n times a s p o t e n t a g a i n s t Lamblia m u r i s . ' ' 5 It a l s o showed good o r a l a c t i v i t y a g a i n s t i n t e s t i n a l amebiasis i n r a t s and h e p a t i c amebiasis i n hamsters due t o ktamoeba h i s t o l y t i c a . Urinary e x c r e t i o n s t u d i e s i n t h e
Chap. 14a
A n t i p a r a s i t i c s, H u m a n
El sl.ager
137 -
When r a t and dog were e n ~ o u r a g i n g . ~ ~ 15,960 R.P. was given o r a l l y t o r a t s i n a s i n g l e 250 mg/kg dose, 40% was recovered i n t h e urine over a 48 h r period. Comparative recovery f i g u r e s for metronidazole and aminitrozole1J2 were 16% and 0.2'$, r e s p e c t i v e l y . In dogs, > 5% of t h e dose was eliminated i n t h e u r i n e w i t h i n 24 h r , of which 70$ was unchanged.75 This suggests t h a t 15,960 R.P. should reach t h e f o c i of i n f e c t i o n i n high concentration a f t e r o r a l administration.
-
AMEBIASIS The i d e a l antiamebic agent must be capable of e r a d i c a t i n g Entamoeba h i s t o l y t i c a from both t h e bowel and from e x t r a - i n t e s t i n a l s i t e s and should be v i r t u a l l y non-toxic. Agents with s u s t a i n e d , p r o p h y l a c t i c antiamebic p r o p e r t i e s a r e a l s o needed. Although many good drugs a r e a v a i l a b l e , no s i n g l e p r e p a r a t i o n i s capable of e x e r t i n g - a l l t h e a c t i o n s r e q u i r e d . ~ ~ ~ ~ ~ that nirid(a ) 2-Amino-5-nitrothiazoles - E a r l i e r s t u d i e demonstrated sa-loza s t r o n g t h e r a p e u t i c e f f e c t s a g a i n s t amebiasis and schistosomiasis ( i n f r a ) i n experimental-animals and i n man. R e s u l t s from r e c e n t human t r i a l s confirm t h a t n i r i d a z o l e , administei:ed i n a dosage of 500 mg b . i . d . o r t . i . d . for 1 0 days, i s h i g h l y e f f e c t i v e a g a i n s t both i n t e s t i n a l and h e p a t i c amebiasis, b u t s i d e - e f f e c t s i n c l u d i n g f r e q u e n t ECG changes and occasional neuropsychic episodes were encountered. 82-84 A l though n i r i d a z o l e goes f a r toward meeting t h e t h e r a p e u t i c requirements of a s i n g l e d i r e c t - a c t i n g amebicide, more extensive t r i a l s a r e needed t o a s s e s s i t s s a f e t y i n man r e l a t i v e t o antiamebic agents i n c u r r e n t u ~ e . ~ ~ o t h e r 2-amino-5-nitrothiazole d e r i v a t i v e s e x h i b i t antiamebic a c t i v i t y .
YYY
( b ) Metronidazole ( X I V ) i s i n e f f e c t i v e a g a i n s t schistosome i n f e c t i o n s but i s w i d e m i c h o m o n i a s i s ( s u p r a ) .'J2 In a r e c e n t notable study, 800 rng of rnetronidazole given t . i . d . for 1 0 days cured 22 out of 2:s p a t i e n t s with a c u t e amebic dysentery, and each of 10 p a t i e n t s with confirmed amebic l i v e r abscess.86 In c o n t r a s t t o t h e n i r i d a z o l e s t u d i e s , no s i g n i f i c a n t ECG changes or n e u r o p s y c h i a t r i c d i s t u r b a n c e s were encountered i n p a t i e n t s r e ceiving metronidazole 86 F u r t h e r l a r g e - s c a l e confirmatory t r i a l s a r e obviously necessary, b u t , on t h e b a s i s of p r e s e n t r e s u l t s , t h e authors sugg e s t t h a t metronidazole may be unique a s a s i n g l e d i r e c t - a c t i n g amebicide, e f f e c t i v e i n t h e bowel and t h e l i v e r , and without s i g n i f i c a n t t o x i c i t y . Many o t h e r n i t r o i m i d a z o l e s also e x h i b i t antiamebic p r o p e r t i e s . 66,67,70
.
( c ) 8-Quinolinols - In r e c e n t c l i n i c a l t r i a l s , clamoxyquin parnoate (Clamo x y l w compared with iodochlorhydroxyyuin i n t h e treatment of d i a r r h e a l disease.87 Clamoxyquin pamoate was administered i n a dose of 16 mg of clamoxyquin base p e r kg d a i l y f o r 5 days. Iodochlorhydroxyquin was given i n a regimen of 1500 mg d a i l y for 1 0 days. Clamoxyquin pamoate was t o l e r a t e d w e l l and was equal t o iodochlorhydroxyquin i n reducing t h e d a i l y number of s t o o l s , i n improving s t o o l consistency, and e l i m i n a t i n g f e t i d odor. Both drugs were e f f e c t i v e i n e l i m i n a t i n g blood and mucus when p r e s e n t i n s t o o l s . Clamoxyquin pamoate was u s u a l l y b e t t e r t h a n iodochlorhydroxyquin i n ameliorating s u b j e c t i v e g a s t r o i n t e s t i n a l symptoms and was s u p e r i o r or equal t o iodochlorh droxyquin i n e l i m i n a t i n g 2.h i s t o l y t i c a , Giardia lamblia, and S h i g e l l a g7
.
~
~
138 -
Sect. I11 - Chemotherapeutic s
Cheney, Ed.
%&&
OH
coNH2
XVII
XVIII Anthramycin methyl e t h e r
Clamoxyquin pamoate
( d ) Anthramycin methyl e t h e r (XVIII)88 had a marked e f f e c t on i n t e s t i n a l amebiasis i n t h e r a t ; s i n g l e o r a l CD50 values a g a i n s t t h e K9 and 200 s t r a i n s of 2. h i s t o l y t i c a were 0.22 and 0.18 mg/kg, r e s p e c t i ~ e l y . The ~ ~ antibiotic a l s o e x e r t e d a d e f i n i t e chemotherapeutic e f f e c t i n experimental i n f e c t i o n s with Trichomonas v a g i n a l i s and Syphacia obvelata. 89
( e l m e t i n e i n h i b i t s p r o t e i n s y n t h e s i s i n c e r t a i n mammalian c e l l s , s p e c i e s of Saccharomyces, and i n Anemia p h ? l T t t , , a higher p l a n t , b u t not i n c e l l f r e e e x t r a c t s prepared from 2. Although d i f f e r e n t i n chemical n a t u r e , (-1-emetine and t h e ipecac a l k a l o i d s show c o n f i g u r a t i o n a l and conf o r m a t i o n a l s i m i l a r i t i e s t o ( ) -cycloheximide and t h e glutarimide a n t i b i o t i c s and have s i m i l a r e f f e c t s on p r o t e i n synthesis." These r e s u l t s d e f i n e a s t r u c t u r a l b a s i s f o r t h e i n h i b i t i o n of p r o t e i n s y n t h e s i s , and suggest a novel s y n t h e t i c approach t o new compounds of p o t e n t i a l i n t e r e s t .
-.
-
-
SCHISTOSOMIASIS - Nearly 200 m i l l i o n people a r e i n f e c t e d with s c h i s t o somiasis, and on a world b a s i s t h e s e i n f e c t i o n s a r e spreading. The degree of prevalence, t h e s e r i o u s n e s s of t h e i n f e c t i o n , and t h e p a u c i t y of adequate drugs make s c h i s t o s o m i a s i s one of t h e g r e a t challenges i n p a r a s i t e chemo92 therapy today. 2,3 S e v e r a l reviews have r e c e n t l y appeared. (a ) 2-Aniino-5-nitrothiazoles - Previous studies3, 79,84 i n d i c a t e d t h a t n i r i d a z o l m h i g h l y a c t i v e a g a i n s t Schistosoma mansoni and 2. japonicum i n animals and showed promise a g a i n s t 2. haematobium and 2. mansoni i n man. I n subsequent c l i n i c a l t r i a l s , 93-100 n i r i d a z o l e given o r a l l y i n d a i l y doses of 20-30 mg/kg f o r 5-10 days a f f o r d e d "cure r a t e s ' ' of 33-100% a a i n s t 2. h a e m a t ~ b i u m ~98J100 ~ - ~ ~ ,and 23-91% a g a i n s t 2. mansoni. 93,96, 97,'10 The drug has u n c e r t a i n value a g a i n s t 5. japonicum i n man.5 Minor drug r e a c t i o n s i n c l u d i n g headache, abdominal pain, nausea and vomiting, and ECG changes were f r e q u e n t l y observed b u t were seldom severe enough t o warrant c e s s a t i o n of therapy. 93-99 However, i n f r e q u e n t b u t s e r i o u s t o x i c r e a c t i o n s , including e p i l e p t i f o r m s e i z u r e s , psychoses, and e p i s t a x i s , were a l s o e n ~ o u n t e r e d . 8 ~ , ~ ~ Therefore, s e v e r a l i n v e s t i g a t o r s have recommended t h a t n i r i d a z o l e be used only under s t r i c t medical s u e r v i s i o n and t h a t unsupervised mass treatment be approached with caution. &-99 S t u d i e s i n mice with 1 4 C n i r i d a z o l e showed t h a t unchanged drug i s taken up from body f l u i d s both by a d u l t S . mansoni and by embryonated eggs, and t h a t metabolites accumulate i n organs of t h e p a r a s i t e .Io1 Rapid metabolic conversion by t h e p a r a s i t e appears t o be r e s p o n s i b l e f o r t h e ensuing t i s s u e damage, p o s s i b l y by causing overloading of a p a r t i c u l a r enzyme system which might be a nikro-reductase .Io1 Other n i t r o t h i a z o l e compounds r e p o r t e d l y have s c h i st osomi c i d a l a c t i v i t y 71,8o , 2 lo2
.
Elslager
A n t i p a r a s i t i cs, Human
Chap. 14a
139 -
( b ) Nitrofurans - Furapromidium (F30066)(XIX) k i l l s S. japonicum -i n vitro and -attic e f f e c t s i n mice and c u r a t i v e a c t i o n i n r a b b i t s and dogs .5 The drug was a c t i v e a g a i n s t 5. japonicum i n e a r l y hixnan t r i a l s , b u t t h e cure r a t e was disappointing a t t h e regimen employed. Iji a r e c e n t t r i a l , furapromidium administered o r a l l y i n doses of 50-100 mg/kg for 1-4.5 months enabled a cumulative negative r a t e of 81$.‘03 The a u t h o r s consider f u r a promidiwn t o be a s u i t a b l e a l t e r n a t i v e when antimonial treatment i s contrai n d i c a t e d . l o 3 Other n i t r o f u r a n s a r e r e p o r t e d t o be a c t i v e .’04,’05
NH (CH2 ) 2 N (C2H5 ) 2 N O 2~ H = C H C O N H C (CH3 H
a , R=H (lucanthone) , R=OH (hycanthone )
2
b
XZFurapromidium ( c ) Lucanthone R e l a t i v e s - Hycanthone (Xxb)J3,’O6 a new m e t a b o l i t e of lucand-noht e a r l i e r t o be much more p o t e n t t h a n lucanthone a g a i n s t 5. mansoni i n harnsters.lo6 However, i n a r e c e n t comparison of t h e r e l a t i v e e f f e c t i v e n e s s of hycanthone a g a i n s t 5. mansoni i n v a r i o u s h o s t s , it was only one-tenth a s a c t i v e i n mice a s i n hamsters.lo7 The drug has pronounced a c t i v i t y a g a i n s t 5. mansoni i n Cebus monkeys,lo7 b u t no r e p o r t s have y e t appeared on i t s e f f i c a c y and t o l e r a n c e i n man. Numerous o t h e r subs t a n c e s r e l a t e d t o lucanthone, hycanthone, and mirasan e x h i b i t a n t i s c h i s t o -
c1J@ CH20H
c1J@ CH~OH
XXI
XXII
CH3
CH3
XXIII
some a c t i v i t y , among which compounds XXI-XXIII a r e r e p r e s e n t a t i v e .108J109
- Preliminary c l i n i c a l r e p o r t s i n d i c a t e d t h a t N- [5(pa-phthalimide (amphotalide )2,110 produces a d e f i n i t e t h e r a p e u t i c response i n S . haematobium i n f e c t i o n s a t f a i r l y w e l l - t o l e r a t e d doses, b u t diminution of t h e v i s u a l f i e l d was observed i n s e v e r a l p a t i e n t s . The search was t h e r e f o r e continued f o r compounds devoid of r e t i n a l t o x i c i t y and more a c t i v e t h a n amphotalide i n experimental animals .lloJ1ll Among hundreds of aminophenoxyalkanes t h a t were synthesized’” and tested,’” XXIV was s e l e c t e d f o r i n i t i a l c l i n i c a l t r i a l . A t o t a l dose of 60-120 mg/kg over 1-4 days cured 16 of 44 s u b j e c t s i n f e c t e d w i t h 2. haematobium. The drug gave r i s e t o no o c u l a r symptoms, b u t d i d produce s e r i o u s vomiting.’” ( d ) Aminophenox alkanes
S e c t . 111 - C h e m o t h e r a p e u t i c s
140 -
XXN
M and B 3 8 3 8 ~
(e)
XXV
Maretin
Cheney, Ed.
XXVI
- The motor responses of S . mansoni t o v a r i -
ous pharmacological agents suggest t h e presence i n t h e worm of an i n h i b i t o r y
,
c h o l i n e r g i c system Carbachol, a r e c o l i n e and a v a r i e t y of c h o l i n e s t e r a s e i n h i b i t o r s produced a p a r a l y s i s of t h e worms which was reversed by a t r o p i n e and by secondary and t e r t i a r y amines, b u t not by quaternary ammonium ganglion blocking agents .l12 T a r t a r emetic and t h e t r i s (2-aminophenyl ) carbonium s a l t s i n h i b i t choline s t e r a s e a c t i v i t y i n s c h i s t o s ~ m e s . ~There i s t h u s some r a t i o n a l e f o r t h e e v a l u a t i o n of p o t e n t i a l c h o l i n e s t e r a s e i n h i b i t o r s a g a i n s t schistosomiasis. Trichlorofon i s r e p o r t e d t o have a c t i v i t y a g a i n s t 5. japonicum i n mice, dogs, and man113 and a g a i n s t 5. haematobium i n man.5y95 However, t e s t s a g a i n s t -S. mansoni i n mice and monkeys showed i n s i g n i f i c a n t a c t i o n by l a r g e o r a l doses of t h e and t h e concentration r e q u i r e d t o produce paralys i s of 2. mansoni i n v i t r o i s r a t h e r high when compared with t h e dosage claimed t o be e f f e c t i v e chemotherapeutically a g a i n s t 5. haematobium and 2. japonicum.’12 Therefore, it i s questionable whether c h o l i n e s t e r a s e inhibi t i o n can account f o r t h e antischistosomal a c t i o n of t r i c h l o r o f o n . It i s perhaps t o o e a r l y t o pass judgment on t h e c l i n i c a l usefulness of t r i c h l o r o f a n , b u t i t s known t o x i c i t y f o r man discourages i t s use.” I n c o n t r a s t with t r i c h l o r o f o n , maretin ( X X V ) and t h e corresponding t h i o a t e e s t e r e x h i b i t e d very potent o r a l a c t i v i t y a g a i n s t 5. mansoni i n mice.113’114 However, n e i t h e r compound showed strong a c t i v i t y a g a i n s t 5. mansoni i n monkeys a t w e l l - t o l e r a t e d dose l e v e l s , and both f a i l e d t o k i l l worms i n v i t r o i n concentrations of 16 pg/ml.l13 The l a c k of i n v i t r o a c t i v i t y suggests e i t h e r an i n s u f f i c i e n t drug concentration i n t h e medium, or conversion t o an a c t i v e metabolite by t h e h o s t . (f) (XXVI) e x h i b i t widespread chemotherapeutic and prophylactic a c t i v i t y a g a i n s t 2. mansoni i n ’ ~ usefulness mice and monkeys and a g a i n s t 2. japonicum i n r n i ~ e . ’ ~ ~ ~ ’ The of t h e s e compounds i n human schistosomiasis has not been evaluated.
INTESTINAL HELMINTHIASES - The world-wide incidence of i n t e s t i n a l h e l minthic i n f e c t i o n s i n man approaches t h e staggering f i g u r e of two b i l l i o n . * The prevalence of t h e s e i n f e c t i o n s and t h e i r complex and far-reaching e f f e c t s upon body f u n c t i o n cause them t o rank among t h e most important disease problems of man. (a ) Drugs Active Against I n t e s t i n a l Nematodes (1)Thiabendazole
- Reports on t h e value of thiabendazole a g a i n s t human
Chap. 1 4 a
A n t i p a r a s i t i c s, H u m a n
El s l a g e r
141 -
helminthiases were summarized r e c e n t l y . 5J117 The drug has broad a c t i o n , p a r t i c u l a r l y i n m u l t i p l e doses, i n suppressing egg production by most of t h e important i n t e s t i n a l nematodes of man, b u t i s r e l a t i v e l y i n e f f e c t i v e a g a i n s t T r i c h u r i s . E f f e c t i v e doses f r e q u e n t l y cause d i z z i n e s s , and t o a l e s s e r e x t e n t nausea and vomiting. R e l a t i v e t o o t h e r a n t h e l m i n t i c s , t h i a bendazole i s l i k e l y t o e x c e l i n t h e treatment of s t r o n g y l o i d i a s i s , creeping e r u p t i o n , and p o s s i b l y t r i c h i n o s i s . ( 2 ) firvinium pamoate2 has been used mainly i n t h e single dose t r e a t m e n t of e n t e r o b i a s i s , b u t more r e c e n t evidence i n d i c a t e s it i s a l s o u s e f u l a g a i n s t s t r o n g y l o i d i a s i s when given over a p e r i o d of 1-2 weeks.’ CI-578, a combinat i o n drug containing pyrviniun pamoate and p i p e r a z i n e , was developed t o i n corporate t h e e f f i c a c y of pyrvinium pamoate a g a i n s t Enterobius v e r m i c u l a r i s and p i p e r a z i n e a g a i n s t Ascaris lumbricoides i n t o a s i n g l e convenient medic a t i o n . I n preliminary c l i n i c a l t r i a l s , CI-578 showed marked a c t i v i t y a g a i n s t s i n g l e or m u l t i p l e pinworm and a s c a r i d i n f e c t i o n s when given i n a s i n g l e o r a l dose (2.5 mg of pyrvinium base and 75 mg of p i p e r a z i n e p e r kg of body weight) on 2 successive day^.^^^,''^ Among 71 s u b j e c t s t r e a t e d , lumbricoides were 98% and 68$, t h e cure r a t e s f o r 2. v e r m i c u l a r i s and r e s p e c t i v e l y ; a s i g n i f i c a n t r e d u c t i o n i n egg counts w a s noted i n t h e r e maining p a t i e n t s . The drug was w e l l t ~ l e r a t e d . l l ~ , ~ ~ ~
A.
( 3 ) Qymanthine hydrochloride (N,N-dimethyloctadecylamine hydrochloride ) i s a c t i v e a g a i n s t Syphacia obvelata and menole i s nana i n mice. I n a p r e i n f e c t e d with Ancylostoma liminary c l i n i c a l t r i a l , 32 of 50 s u b j e c t s (64 duodenale were cured following a s i n g l e o r a l 50 mg/kg dose of dymanthine hydro ch l o r i de 2o Ga st ro i n te st in a l si de -ef f e ct s were f r e querit l y observed but were m i l d . and amenable t o symptomatic treatment.12’
.’
w
(4) 1,4-Phenylenediisothiocganate (XXVII)was r e p o r t e d e a r l i e r t o be e f f e c t i v e a g a i n s t nematodes and cestodes i n experimental animals. Subsequently, t h e drug was administered t o 43 p a t i e n t s with hookworm d i s e a s e i n a dose of 300 mg every 12 hr.121 Among 38 p a t i e n t s followed-up, 21 (55%) were cured and 13 o t h e r s showed a s u b s t a n t i a l r e d u c t i o n i n egg count. Mild g a s t r o i n t e s t i n a l s i d e - e f f e c t s were noted i n 17 s u b j e c t s .I2’ ( 5 ) Other Anthelmintics - = f o r t s d i r e c t e d p r i m a r i l y toward t,he development of a n t h e l m i n t i c s f o r v e t e r i n a r y use (Chapter 14b) have recent,ly y i e l d e d a v a r i e t y of a c t i v e nematocides of p o t e n t i a l u s e f u l n e s s i n man.” Among them, various benzimidazoles, 769122-124 t e t r a m i s o l e (XXVIII)and r e l a t i v e s , 1 2 5 N=C=S
N=C=S
XXVII
XXVIII Tetramisole
XXIX
Fyrantel
I42
Sect. 111
xxx
- Chemotherapeutics
XIMI
Cheney, Ed.
XXXII
Nitrodan
p y r a n t e l (xXIX)126 and analogs,127 1,2,4-oxadiazoles ( X X X ! ,128 n i t r o d a n (=I) ,129,130 and imidazodiquinolinium s a l t s (XXXII)131 a r e noteworthy. ( b ) Drugs Active Against Cestodes Paromomycin s u l f a t e i s a b a s i c oligosaccharide-type a n t i b i o t i c with unique a c t i o n a g a i n s t Entamoeba and Trichomonas 2, It has r e c e n t l y been reported t o be highly e f f e c t i v e a g a i n s t t h e human tapeworms Taenia sa i n a t a , Taenia 9-solium 133 and flymenolepis Doses o ~ o $ k & ~ ' for 3-5 days were most f r e q u e n t l y employed, although l a r g e r s i n g l e doses were a l s o e f f e c t i v e .lS Subsequent s t u d i e s i n animals showed t h a t paromomycin had inconsequential e f f e c t a g a i n s t g. i n mice or 2. diminuta i n i n r a t s , b u t s t r o n g a c t i o n a g a i n s t flydatigera taeniaeformis i n v i t r o and i n cats.135 Although t h e mode of a c t i o n of paromomycin a g a i n s t p a r a s i t e s i s unknown, it i n h i b i t s t h e i n c o r p o r a t i o n of amino a c i d s i n t o t h e t r y p s i n s o l u b l e p r o t e i n f r a c t i o n of Staphylococcus aureus 257. 136 A t t h e ribosomal l e v e l , paromortiycin prevents t h e attachment of amino acyl-s-RNA and causes accumulation of m-RNA.136
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Chemotherapeutics
Cheney, Ed.
(124) M o n s a n t o L t d . , Belg. P a t e n t 673, 983; S. A f r . P a t e n t 2 1 5 5 / 6 5 ( 1 9 6 6 ) . (125) A. H. M. R a e y m a e k e r s , F. T. N. Allewijn, J . Vandenberk, P. J . A. Demoen, T. T. T. Van Offenwert, a n d R. A. J . J a n s s e n , J. Med. C h e m . , 9, 5 4 5 (1966). (126) W. C. A u s t i n , W.-Courtney, J . C. Danilewicz, D. H. M o r g a n , L. H. C o n o v e r , H. L. Howes, J r . , J . E. Lynch, J. W. M c F a r l a n d , R. L. C o r n w e l l , a n d V. J . T h e o d o r i d e s , N a t u r e , 212, 1273 (1966). (127) P f i z e r L t d . , Belg. P a t e n t s 658, 987; 681, 250; 681, 413; 684, 437
(1965-7). (128) C. A i n s w o r t h , W. E. Buting, J . Davenport, M. E. C a l l e n d e r , a n d M. C. McCowen, J. Med. C h e m . , 10, 208 (1967). (129) W. C. M c G u i r e , R. C. O'Neill, a n d G . B r o d y , J. P a r a s i t o l . , 52, 528 (1966). (130) S. E. L e l a n d , J r . , J. N. Kling, a n d L. J . Wallace, i b i d . ,53, 20 (1967). (131) C. S. F r a n k l i n , U. S. P a t e n t 3, 253, 986 (1966). (132) A. Ulivelli, A t t i Congr. Ital. P e d i a t . 30th, 2, 239 (1964). (133) V. P i a z z a , 0. R e s t i v o , a n d G. Sindoni, Clin. T e r a p . , 34, 31 3 (1965) (134) J . P. G a r i n , J . D e s p e i g n e s , a n d M. S i r o t , Lyon M e d . , 215, 679 (1966). (135) J . A. Waitz, P. McClay, a n d P. E. Thompson, J. P a r a s i t o l . , 52, 830 (1966). (136) von S e e f r i e d a n d D. C. J o r d a n , Can. J . M i c r o b i o l . , 12, 1157 (1966).
A.
I
147
Chapter 1 4 ( b ) . Animal A n t i p a r a s i t i c Agents D a l e R. Hoff, Merck Sharp & Dohme Research L a b o r a t o r i e s D i v i s i o n of Merck & Co., I n c . , Rahway, N e w Jersey A n t h e l m i n t i c s f o r Treatment of Roundworm I n f e c t i o n s P y r a n t e l t a r t r a t e , r e p r e s e n t i n g a new c l a s s of a n t h e l m i n The t h e r a p e u t i c p r o p e r t i e s of tetramis o l e , r e p o r t e d i n t h e p r e v i o u s y e a r , w e r e confirmed i n a series of p a p e r s d e s c r i b i n g l a b o r a t o r y and f i e l d s t u d i e s . The d a t a p r e s e n t l y a v a i l a b l e i n t h e p u b l i s h e d l i t e r a t u r e are n o t y e t s u f f i c i e n t t o a l l o w a d e t a i l e d comparison of t h e s e new a n t h e l m i n t i c s and t h i a b e n d a z o l e , b u t some important s i m i l a r i t i e s and d i f f e r e n c e s can now b e discerned. A l l t h r e e a r e broad-spectrum and are e f f i c a c i o u s a g a i n s t many species of i m p o r t a n t nematodes p a r a s i t i z i n g t h e e n t i r e g a s t r o i n t e s t i n a l tract of c a t t l e and sheep. Poor c o n t r o l of T r i c h u r i s i s a weakness common An i m p r e s s i v e b r e a d t h of spectrum f o r t e t r a m i s o l e w a s t o a l l three. s u g g e s t e d i n t h e p r e l i m i n a r y announcement of t h i s d r u g , i n which a c t i v i t y a g a i n s t a t l e a s t 56 s p e c i e s of nematodes i n t h i r t e e n h o s t s was 1isted.l
t i c s , was announced i n 1966.
P y r a n t e l t a r t r a t e has a somewhat h i g h e r s a f e t y f a c t o r t h a n t e t r a m i s o l e , a c c o r d i n g t o p u b l i s h e d a c c o u n t s ( s e e T a b l e I ) , though n e i t h e r approaches t h e h i g h t h e r a p e u t i c i n d e x r e p o r t e d f o r thiabendazole. D i f f e r e n c e s i n t h e e f f e c t s of t h e s e t h r e e a n t h e l m i n t i c s a g a i n s t lungworm i n f e c t i o n s m a y b e due t o t h e v a r i e d p h y s i o l o g i c a l d i s p o s i t i o n s of t h e s e d r u g s , r e f l e c t i n g d i f f e r e n c e s i n a b s o r p t i o n and metabolism. T e t r a m i s o l e w a s r e p o r t e d t o b e e f f e c t i v e a g a i n s t lungworms. Thiabendazole, which i s r a p i d l y m e t a b o l i z e d , has been shown t o have a s i g n i f i c a n t e f f e c t a g a i n s t lungworms ( v i d e i n f r a ) , although Pyrantel t a r t r a t e , not being s p e c i a l dosing s c h e d u l e s are r e q u i r e d . w e l l absorbed from t h e i n t e s t i n e , w a s s a i d t o b e i n a c t i v e a g a i n s t lungworms.2
--
A comparison of t h e r e l a t i v e p o t e n c i e s ( i n t e r m s of recommended o r a l doses f o r c o n t r o l of p a r a s i t i c g a s t r o e n t e r i t i s i n s h e e p ) , minimum l e t h a l dose ( s h e e p ) , and t h e s a f e t y f a c t o r f o r t h e s e t h r e e substances i s given i n t h e t a b l e : TABLE I Effective Safety ComDound Facto r Dose MLD
-
Pyrantel Tartrate Tetramisole Thiabendazole
25 mg/kg 15 m d k g 44 mg/kg
180 mg/kg3 4 80 mg/kg4a
>lo00 mg/kg
ca. ca.
73
- 4-5 i -234a
Sect. 111 - C h e m o t h e r a p e u t i c s
148 -
Cheney, Ed.
Pyrantel T a r trate T h i s s u b s t a n c e , which h a s t h e s t r u c t u r e t r a n s - l - m e t h y l - 2 -
[2-(2-thienyl)vinyl]-1,4,5,6-tetrahydropyrimidine ( I ) , w a s t h e most p r o m i s i n g member of a new c l a s s of a n t h e l m i n t i c s announced by
coworker^.^ These compounds e v o l v e d from l a b o r a t o r y assays employing N e m a t o s p i r o i d e s d u b i u s i n m i c e and N i p p o s t r o n g y l u s muris i n rats. From a b r i e f d i s c u s s i o n of s t r u c t u r e - a c t i v i t y r e l a t i o n s h i p s i n t h e s e r i e s , i t a p p e a r s t h a t a lower o r d e r of anthelmintic p o t e n c y w a s f o u n d w i t h r e l a t i v e s i n which t h e i n t e r c y c l i c v i n y l e n e l i n k a g e was f u l l y s a t u r a t e d o r i n which t h e t e t r a h y d r o p y r i m i d i n e r i n g was r e p l a c e d w i t h an i m i d a z o l i n e . M e t h y l a t i o n of t h e s e c o n d a r y r i n g n i t r o g e n w a s b e n e f i c i a l , and i n t r o d u c t i o n of a methyl s u b s t i t u e n t i n t o t h e 3 - p o s i t i o n of t h e t h i o p h e n e r i n g a p p a r e n t l y l e a d s t o enhanced potency
W. C. A u s t i n and
.
D e s c r i p t i o n of chemical p r o c e d u r e s f o r p r e p a r a t i o n of pyr a n t e l s a l t s and r e l a t e d s t r u c t u r e s a p p e a r e d i n a s e r i e s of P f i z e r patents.6-9
p'\cA3 I
H
.C4H606
i?
1
CH3 Pyrantel T a r t r a t e I
duced d e g r a d a t i o n . 3
P y r a n t e l t a r t r a t e was d e s c r i b e d as a c o l o r l e s s c r y s t a l l i n e m a t e r i a l which i s s o l u b l e i n w a t e r Solutions a r e sensi(180 m g / m l ) . t i v e t o u l t r a v i o l e t l i g h t , undergoing t r a n s - c i s i s o m e r i z a t i o n upon p r o l o n g e d exposure. Storage i n dark b o t t l e s i s s u f f i c i e n t t o protect solutions against light-in-
--
In l a b o r a t o r y t r i a l s , t h e s u b s t a n c e , a d m i n i s t e r e d o r a l l y as a 5% s o l u t i o n i n w a t e r , gave good c o n t r o l of T r i c h o s t r o n g y l u s colubrif o r m i s i n f e c t i o n s of s h e e p a t 45 mg/kg o r 25 mg/kg.3 Doses of 12.5 o r 25 mg/kg r e s u l t e d i n s u b s t a n t i a l l y complete e l i m i n a t i o n of N e m a t o d i r u s b a t t u s from e x p e r i m e n t a l l y i n f e c t e d lambs. I n a t r i a l with n a t u r a l l y i n f e c t e d s h e e p , p y r a n t e l t a r t r a t e a t 25 mg/kg, o r a l l y , was e f f e c t i v e i n t h e removal of O s t e r t a g i a , T r i c h o s t r o n g y l u s , N e m a t o d i w C o o p e r i a , and C h a b e r t i a , b u t had l i t t l e e f f e c t on T r i c h u r i s . j Death of one lamb o u t of s i x was s e e n f o l l o w i n g u s e of an o r a l d o s e of 180 mg/kg. 100 mg/kg w a s w e l l t o l e r a t e d i n t w e l v e sheep.
-
E f f i c a c y of p y r a n t e l f o r t h e p r e v e n t i o n of p a r a s i t i c g a s t r o e n t e r i t i s i n s h e e p w a s d e m o n s t r a t e d i n f i e l d t r i a l s w i t h lamb f l o c k s h a r b o r i n g v a r i a b l e b u t moderate i n f e c t i o n s of Nematodirus, O s t e r t a g i a , T r i c h o s t r o n g y l u s , and Haemonchus.l0t1l Under t h e c o n d i t i o n s of t h e s e t r i a l s , p y r a n t e l was found t o r e s u l t i n somewhat g r e a t e r a v e r a g e daily weight g a i n s t h a n t h e o t h e r a n t h e l m i n t i c s u s e d f o r comparison ( b e phenium, m e t h y r i d i n e , t h i a b e n d a z o l e ) , though t h e o b j e c t i o n w a s made l a t e r t h a t t h e t h i a b e n d a z o l e dose u s e d i n t h e Nematodirus t r i a l s was
Antiparasitics, Animal
Chap. 14b
Hoff
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less than the dose recommended by the manufacturer for control of Nematodiriasis.12 Reference was also made to good activity with pyrantel against Ascaris in swine and against Toxocara and Toxascaris indogs5 Tetramisole The circumstances which led to the discovery of tetramisole (11, Ar = C6H5), a new broad-spectrum anthelmintic, were describedin
two papers from the Janssen Laboratories.l,13 2-Acetylimino-3-[2-hy droxy-2-(2-thienyl)ethyl]thiazoline (Thiazothienol, IV), which was under investigation as an anthelmintic in poultry and sheep, was found to undergo metabolism in these species to the more potent 6-(2 thieny1)-5,6-dihydroimidazo[Z,l-b]thiazole (111, Ar = 2-thienyl). This metabolic transformation was not observed in rats or mice. Tetramisole was the product of systematic development of reduced imidazo[2,1-b]thiazoles of the types I1 and 111. Thirty-three examples of both types were desI1 11 I cribed,l3 but detailed structureactivity relationships were not Tetramisole, Ar = C6H5 discussed.
Ej3
cxzg-Ar I
IV
A more detailed report of the metabolic studies with thiazothienol appeared in a new paper by Allewijn and Demoen.14
Walleye examined the action of tetranisole against natural and experimental infections with parasitic nematodes in 1076 sheep and 18 goats. Oral doses of 15 mg/kg gave good results against adult and immature roundworm species in the abomasum and intestines, with the exception of Trichuris. The same dose, or 10 mg/kg, was effective against the lungworm Dictyocaulus filaria in these species. At 10 mg/kg, the drug resulted in 82-94% removal of immature lungworms seven days post-infection, and 41% three days after infection (sheep). Slight side-effects were observed with doses of 15-20 mgkg, orally4; the animals showing depression or occasional twitches. Convulsions followed administration of 50 mg/kg doses, but the animals recovered. One of twenty sheep dosed with 80 mg/kg died. Efficacy of tetramisole against a broad spectrum of gastrointestinal parasites and lungworms in sheep and goats was confirmed in a series of field trials by several in~estigators.l~-~1 R o s s 1 6 found that tetramisole at 12.5 or 15 mg/kg, orally, was effective against 3-day-old or adult Ostertagia circumcincta, but failed to remove a high proportion of the parasites when gived ten
Sect. 111
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Chemotherapeutics
days a f t e r i n f e c t i o n . FitzsimmonsZ1 n o t e d e r r a t i c a c t i o n of t e t r a m i s o l e ( 1 2 . 5 o r 25 mg/kg, P.o.) a g a i n s t 3 r d and 4 t h - s t a g e l a r v a e of T r i c h o s t r o n g y l u s colubriformis i n q - o a t s . though t h e agent w a s h i g h l y e f f e c t i v e against t h e a d u l t s of t h i s s p e c i e s a t b o t h l e v e l s . GuilhonZ0 r e c o r d e d incomplete removal of Bunostomum t r i gonocephalum even a t 20 mg/kg sub-cutaneously ( s h e e p ) . W a l l e y y o n t h e o t h e r hand, showed good c o n t r o l of Bunostomum spp. a t 10 mg/kg, s.c., i n two s h e e p , and g e n e r a l l y good c o n t r o l of t h e s e s p e c i e s w i t h t h e s t a n d a r d o r a l d o s e s , a l t h o u g h t h e r e s u l t s w e r e somewhat e r r a t i c .
-
GuilhonZ0 observed d e a t h s of sheep u s i n g 50 mg/kg of tetrak. i s o l e , sub-cutaneously. Walley4 s u g g e s t e d t h a t 50 mg/kg i s t h e toxic dose f o r p a r e n t e r a l t e t r a m i s o l e , b u t n o t e d t h a t t h e compound i s more e f f e c t i v e by t h i s r o u t e , hence t h e t h e r a p e u t i c index s h o u l d not b e substantially altered. P r e l i m i n a r y a c c o u n t s of t r i a l s w i t h t e t r a m i s o l e i n c a t t l e have appeared.22,23 A subcutaneous dose of 10 mg/kg gave goodresults a g a i n s t a d u l t and immature D i c t y o c a u l u s v i v i p a r u s , O s t e r t a g i a , and Cooperia, except f o r poor c o n t r o l of f i f t h - s t a g e l a r v a e of O s t e r t a g h . N e a r l y a l l c a l v e s r e c e i v i n g- t h i s t r e a t m e n t showed moderate s i g n s of t o x i c i t y , and t i s s u e r e a c t i o n s w e r e observed a t t h e i n j e c t i o n s i t e i n about h a l f of t h e animals. Thiabendazole Thiabendazole ( V ) w a s found e f f e c t i v e a g a i n s t l a r v a l and a d u l t lungworms of c a t t l e , D i c t y o c a u l u s v i v i p a r u s , b u t o n l y under s p e c i a l i z e d c o n d i t i o n s o f U s e of t h r e e consecuV t i v e d a i l y i n t r a m u s c u l a r i n j e c t i o n s of 33-110 mg/kg r e s u l t e d i n 100% c l e a r a n c e of immature p a r a s i t e s (15-17 days p o s t - i n f e c t i o n ) . Three d a i l y treatments w i t h 44 mg/kg of t h i a b e n d a z o l e , i n t r a m u s c u l a r l y , removed 95.5% of a d u l t D. v i v i p a r u s . O r a l , intratracheal, o r intraperitonealroutes w e r e inefFective o r unsatisfactory.24,25,26 The l a c k of effectiveof s i n g l e d o s e t r e a t m e n t s w i t h t h i a b e n d a z o l e f o r t h e t r e a t m e n t of lungworms w a s a t t r i b u t e d t o t h e known27,28 r a p i d c o n v e r s i o n of t h i s substance t o i n a c t i v e metabolites. I r r i t a t i o n and r e s i d u e s a t t h e i n j e c t i o n s i t e l i m i t t h e u s e f u l n e s s of p r e s e n t l y a v a i l a b l e dosage forms of t h i a b e n d a z o l e f o r i n t r a m u s c u l a r t r e a t m e n t of lungworm infect ions. The r a t lungworm, Angiostrongylus c a n t o n e n s i s , w a s removed by 200 mg/kg d o s e s of t h i a b e n d a z o l e . 29 Thiabendazole w a s r e p o r t e d e f f e c t i v e a a i n s t mature Oesophagostomum spp. i n swine a t a r a t e of 66 mg/kg 7p.o. ) , b u t to-
-
Antipara sitic s, Animal
Chap. 14b
Hoff
151
without effect against the tissue-phase parasites at 5 days after infection. 30 The effects of thiabendazole on therapy - - and prophylaxis - - of Trichinella spiralis in swine were described by Campbell and Cuckler. 31 Other Nematocides
A new installment in the interesting story of the selective effect of haloxon (VI) on helminth cholinesterase appeared recently?2 It had been shown earlier that the phosphorylated enzyme; i.e., bis(dich1oroethoxy)-phosphoryl cholinesterase, which arises from interaction of haloxon with a cholinesterase of sheep, dephosphorylates rapidly compared to the corresponding phosphorylated enzyme which formed from haloxon and cholinesterase from Haemonchus contc~rtus.~~3 The higher therapeutic index of haloxon relative to older organophphate anthelmintics was attributed to this observed biochemical difference between host and parasite.
-- -
The study has now been extended to include parasitic nenatodes other than H. contortus. It was found that three other species which are sensitive to haloxon; (C1CH2CH20)2P0 namely Oesophagostomum venulosum, 0. dentatum, and Ascaris lumbriHaloxon coides, also contain a cholinesterase which is efficiently deactiwted VI by haloxon. The original hypothesis for the basis of selectivity observed with haloxon was supported by the observation that phosphorylated enzymes from Dictyocaulus filaria, a sDecies which is not sensitive to haloxon and from Bunostomum trigonocephalum, which has only fair susceptibility to haloxon, are raDidlv reactivated. Dresumablv via ready deDhosDhorvlation. Three nematode species which are normally located in the large intestine gave quite different results. Though infections with these species do not respond readily to treatment with haloxon, cholinesterase from the parasites was rapidly deactivated by the drug. Failure of the correlation with these helminths was attributed to the possibility that their physical location protects them from lethal concentraticns of the anthelmintic.
R
-
-
I
I
-
The correlations between specific anticholinesterase inhibition and anthelmintic action of haloxon is not perfect, but they help to explain the unusual properties of this drug. Perhaps the information derived from these studies will lead to discovery of new anthelmintic organophosphates with even higher selectivity of action between nematodes and mammals. 3-Methyl-5-(p-nitrophenylazo) rhodanine (Nitrodan@, VII ) is an interesting anthelmyntic with quite a different spectrum of actim from the nematocides discussed above.
Sect. 111 - Chemotherapeutics
152 -
Cheney, Ed.
e2
When administered continuously in the diet of experimental animals, it brought about the removal of the pinworm Syphacia obvelata in mic9 *?S/ Ascaridia galli in chickens, and ToxVI I canis, Ancylostoma caninum, and -ocara -. Uncinaria stenocephala in dogs. The effective dose levels were dependent upon duration of treatment and ranged from 0.016% to 0.1% in the diet.35
CH3-N I CH (f=O -N=N
--
The drug was ineffective against Nippostrongylus muris, Aspicularis tetraptera, or Nematospiroides dubius in mice and Toxascaris leonina in doas. Anthelmintics for the Treatment of Liver Fluke Infections Oxyclozanide The utility of oxyclozanide (VIII) for treatment of adult liver fluke infections in cattle and she was demonstrated in laboratory tesfs%p and effective several against field trials.38-40 adult flukes in It was
cQco*t-j c1
- c1
sheep at 15 mg/kg, and in cattle at 10-15 mg/kg. Toxic side-effects were observed in doses above 30 mg/kg, wii5 Oxycloz anide deaths occurring at 60 mg/kg (sheep VIII and cattle). The safety factor was considered to be four in average animals, but less in those whichare dehydrated or suffering from extensive liver damage. Like the other fasciolacides now available37, oxyclozanide has an effect against immature flukes (6 weeks or older), but only at higher and toxic dose levels.36,37,39 M&B 10.755
Preliminary accounts of a newer modification of the nitrophenol class of anthelmintics appeared.41,42 This compound, M&B 10,755 (IX), was reported active at 8 mg/kg in sheep or calves (1/5 of the maximum tolerated dose) against mature Fasciola hepatica,whm given intramuscularly or subcutaneously. Activity against immature (4-6 weeks) flukes was observed at the higher dose of 20 mg/kg (1/2 of the MTD). Oral dosing was less satisfactory.
/
IM&B Q’ 10,755 N IX
A aper by Boray, Happich, and Andrews3? contains a comparative study of the liver fluke agents c a r h tetrachloride, hexachloroethane, hetol ( 1,4-bis-trichloromethylbenzene),hexachlorophene, hexachlorophene monophosphate, Hilomid@ (a combination of
-
Antipara sitic s , Animal
Chap. 14b
Hoff
153 -
3,5,4T-tribromosalicylanilide and 5,4t-dibromosalicylanilide), 2 , 2 ' dihydroxy-3,3T-dichloro-5,5'-dinitrobiphenyl, oxyclozanide, and disophenol (2,6-diiodo-4-nitrophenol). None of these substances was ef-
fective against 4 - or 6-week-old infections at the doses which aread equate for eradication of mature flukes. Removal of these immature parasites could be demonstrated with all of the compounds tested, but in every case only at toxic levels. The authors emphasized the importance of anthelmintics effective against immature infections, particularly for controlling acute outbreaks of fascioliasis. There exists a clear need for new fasciolacides which are capable of eradicating immature liver flukes at safe doses. Coccidiosis Buquinolate Many examples of a variety of alkyl 4-hydroxy-6,7-dialkoxy(X) were found to possess a high order of coccidiostatic activity when tested for prevention of experimental Eimeria tenella infections in chicks.43 The preferred examples were ethyl esters, but relative un potency was most sensitive to 1 the nature of the alkoxy group in the 6- and 7-positions of the quinoline ring. R1 was RO varied from methyl to propyl, X isopropyl, and allyl. SimiBuquinolate, R = (CH3)2CHCH2;R1 = C2H5. larly, homologous series wherein the groups R and C1 to Cl0 straight - and brancbed-chain hydrocarbon residues were examined. Highest potency was obtainedwith 6,7-@-( isobutoxy )quinolines, and ethyl 4-hydroxy-6,7-bis-(isobutmy) -quinoline-3-carboxylate [X, R1 = C2Hs, R = (CH ) CHCH2Js selected 3 2 for extensive evaluation and was given the generic name buquinolate. quinoline-3-carboxylates
Roc2 -1
T
In laboratory and pen trials, buquinolate at 0.00825% in the diet was effective for protection of chicks from mortality and A dietary morbidity due to exposure to nine species of level of 0.00825% of buquinolate was judged similar in coccidiostatic efficacy to a combination of amprolium (XI) (0.0125%) and ethopabate (XII) (0.0004%).46
Ampr oliurn XI
Qc2H5 kC0CH 3 Ethopabate
XI I
Buquinolate was found to be poorly absorbed from the chicken intestine48, and to possess low acute and sub-acute toxicit ies 4 ' The maximum tolerated single oral doses were r p rte to be in of 30 gykg and l O T g
154 -
Sect. 111
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Chemotherapeutics
Cheney, Ed.
in chickens and turkeys, respectively, and greater than 7.5 g/kg in mice and rats. Chickens tolerated continuous feeding of a diet concentration of 0.088% for 31 days or 0.044% for ten weeks without signs of toxicity. Use of up to three times the recommended dose in chickens had no adverse effect on growth. 44-45,50-53 The recommended dietary level of 0.00825% was said to have no harmful effect on feed conversion, egg production, egg quality, hatchability, or fertilit~.51,5~,53Lower efficiency against turkey coccidiosis was suggested in one report.44 The coccidiostatic nature of buquinolate was demonstrated by resumption of development of E, necatrix infections which couldbe observed seven days following withdrawal of the drug. 54. Quinolines related in structure to buquinolate were described as coccidiostats in a recent patent from Imperial Chemical Industries. 55 Metic1orpindo1 In preliminary accounts, 2,6-dimethyl-3,5-dichloro-4-hydroxypyridine (meticlorpindol, XIII), was reported to afford good protection against nine species of coccidia in chicks when fed in the diet at 0.0125%.56,57 Weight gains and feed efficiency in birds treated with meticlorpindol were judged good. Novastat
@
CpJ..
Brown, Mueller, and M o r e h ~ u s ere~~ ported studies with 2-chloro-4-nitrobenzamide CH a 3 (XIV) and combinations of XIV with N-(E-nitrophenyl)-4-acetamidobenzenesulfonamide ( X V ) Meticlorpindol against coccidiosis. These authors noted that XI I1 tolerated levels of XIV were able to protect chickens from mortality due to exposure to E. necatrix or E. tenella, but that protection against E. acervulinacould be achTeved only at toxic levels with XIV alone. A combination equivalent to a final dietary concentration of 0.025% of XIV and 0.020% of X V , designated Novastat prevented development of coccidiosis when tested against all three Eimeria species E. tenella, E. necatrix, and E. acervulina. Use of Novastat @ resulted in no reduction of growTh response in chicks, and a 3.9% improvement infeed efficiency, relative to uninfected, unmedicated controls. SO NHC6Hq -NO2(P -) 1 2
a
-
Q
Q
XIv
XV
Chap. 14b
155 -
Hoff
Antiparasitic s, Animal References
(1) D. T h i e n p o n t , 0. F. J. V a n p a r i j s , A. H. M. R a e y m a e k e r s , J. V a n d e n b e r k , P. J. A. D e m o e n , F. T. N. A l l e w i j n , R. P . H. M a r s b o o m , C. J. E. N i e m e g e e r s , K. H. L. Schellekens, and P. A. J. J a n s s e n , N a t u r e , 209, 1084 (1966). (2) W. C. A u s t i n , L e c t u r e p r e s e n t e d a t t h e T e n t h N a t i o n a l M e d i c i n a l C h e m i s t r y S y m p o s i u m , A C S D i v i s i o n of Medicinal C h e m i s t r y , B l o o m i n g t o n , I n d i a n a , J u n e 28, 1966. (3) R. L. C o r n w e l l , V e t . R e c o r d , 79, 590 (1966). (4) J. K. W a l l e y , V e t . R e c o r d , 787406 (1966). (4a) S. P. H e b d e n , A u s t r a l i a n V e E J., 37, 264 (1961). (5) W. C. A u s t i n , W. C o u r t n e y , J. C. D G i l e w i c s , D. H. M o r g a n , L. K Conover, H. L. H o w e s , Jr., J . E. Lynch, J. W. McFarland, R. L. Cornw e l l , and V. J. T h e o d o r i d e s , N a t u r e , 212, 1273 (1966). (6) Chas. P f i z e r & Co., I n c . , B e l g i a n P a t e n t 658,987 (1965). (7) Chas. P f i z e r & Co., I n c . , B e l g i a n P a t e n t 681,413 (1966). (8) C h a s . P f i z e r I% Co., I n c . , B e l g i a n P a t e n t 681,250 (1966). (9) C h a s . P f i z e r & Co., I n c . , U.S. P a t e n t 3,291,688 (1966). (10) R. L. C o r n w e l l , J. B e r r y , T. C. L i g h t , E. A. Mercer, and G. P h i l l i p s , V e t . R e c o r d , 79, 626 (1966). (11) R. L. C o r n w e l l , J . B e r r y , T. C. L i g h t , E. A. Mercer, G. Phillips, and D. A. P u l l e n , V e t . R e c o r d , 79, 723 (1966). (12) P. A. K. A s h t o n , V e t . R e c o r d , 79, 718 (1966). (13) A. H. M. R a e y m a e k e r s , F. T. N . A l l e w i j n , J. V a n d e n b e r k , P. J . A . D e m o e n , T. T. T. V a n O f f e n w e r t , and P. A. J. J a n s s e n , J . Med. C h e m . , 9. 545 (1966). (14) F. T. N. A l l e w i j n and P. J. A. D e m o e n , J. P h a r m . S c i . , 55, 1028 (1966) (15) J. W. Pankhurst and D. 0. S u t t o n , V e t . R e c o r d , 79, 166 (1966). (16) D. B. R o s s , V e t . R e c o r d , 79, 392 (1966). (17) T. E. G i b s o n , V e t . R e c o r d T - 7 9 , 601 (1966). (18) B. A. F o r s y t h , A u s t r a l i a n V z . J., 412 (1966). (19) 0. N i l s s o n , and L. S o r e l i u s , N o r d . V e t e r i n a r m e d . , , 18, 314 (1966) (20) J. G u i l h o n , C o m p t . R e n d . , 262, 1959 (1966). (21) W. M. F i t z s i m m o n s , V e t . R e c o r d , 79, 599 (1966). (22) J. S. R e i n d e r s , T i j d s c h r . D i e r g e G e s k , 91, 967 (1.966). (23) K. Enigk, M. Stoye, and H. J. B u r g e r , D G t . T i e r a e r z t l . Wochschz, 73, 441 (1966). (24) D. B. R o s s , V e t . R e c o r d , 2, 300 (1966). (25) R. R u b i n and E. R. Ames, Am. J. V e t . R e s . , 27, 997 (1966). 266 (1966). (26) M. R o b i n s o n , A u s t r a l i a n V e t . J . , (27) D. J. TOCCO, R. P. Buhs, H. D. B r o w n , A. R. Matzuk, H. E. M e r t e l , R. E. H a r m a n , and N. R. T r e n n e r , J. Med. C h e m . , 7, 399 (1964). (28) D. J. TOCCO, C. R o s e n b l u m , C. M. M a r t i n , anz H. J . R o b i n s o n , Toxicol. A p p l . P h a r m a c o l . , 31 (1966). (29) K. N i s h i m u r a , C h e m o t h e r a p i a , 10, 164 (1965/66). (30) L. F. T a f f s , V e t . R e c o r d , 79,671 (1966). (31) W. C. C a m p b e l l and A. C. G k l e r , J. P a r a s i t o l . , 52, 260 .(1966). (32) R. J. H a r t and R. M. L e e , Exp. P a r a s i t o l . , 18, 332-(1966).
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.
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Sect. 111 - Chemotherapeutics
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( 3 3 ) R. M. L e e and M. R. Hodsden, Biochem. Pharmacol., 1 2 , 1241(1%3). ( 3 4 ) R. M. L e e , Biochem. Pharmacol., 1551 ( 1 9 6 4 ) . ( 3 5 ) W. C. McGuire, R. C. O ' N e i l l , and G. Brody, J. P a r a s i t o l . , 52, 528 ( 1 9 6 6 ) . ( 3 6 ) A. W. Broome and W. G. M. J o n e s , Nature, 210, 744 ( 1 9 6 6 ) . ( 3 7 ) J. C. Boray, F. A. Happich, and J. C. Andrews, V e t . Record, 80, 218 ( 1967) . ( 3 8 ) J. J. Vaughan, V e t . Record, 79, 720 ( 1 9 6 6 ) . ( 3 9 ) J. K. W a l l e y , V e t . Record, 7 F 267 (1966). ( 4 0 ) F. H. K e l s e y , V e t . Record, 78, 303 ( 1 9 6 6 ) . ( 4 1 ) M. Davis, J. M. S. Lucas, JTRosenbaum, and D. E. Wright, Nature, 211, 882 ( 1 9 6 6 ) . ( 4 2 ) J. Guilhon, Compt. Rend., 263, 1234 ( 1 9 6 6 ) . ( 4 3 ) C. F. Spencer, A. Engle, C.-N. Yu, R. C. F i n c h , E. J. Watson, F. F. E b e t i n o , and C. A. Johnson, J. Med. Chem., 9 , 934 ( 1 9 6 6 ) . ( 4 4 ) S. A. Edgar and C. Flanagan, P o u l t r y S c i . , 43, 1081 ( 1 9 6 6 ) . ( 4 5 ) A. T. Engle, R. P. Humphrey, and C. A. Johnson, P o u l t r y S c i . , 4 5, 1082 ( 1 9 6 6 ) . ( 4 6 ) W. D. Morrison, A. E. Ferguson, M. C. C o n n e l l , and J. K. M Q a p r , P o u l t r y S c i . , 4 5 , 1107 ( 1 9 6 6 ) . E. J. D a y , and J. E. French, P o u l t r y S c i . , 45, ( 4 7 ) C. R. Sad=,, 1120 ( 1966) . ( 4 8 ) R. J. H e r r e t t , C. W. W i l l i a m s , G. M. K l e i n , and J. P. H e o t i s , P o u l t r y Sci., 45, 1092 ( 1 9 6 6 ) . ( 4 9 ) A. R. B o r z a n n , R. A. Levin, D. L. G i l b e r t , R. Cooley, and J. P. P r y t h e r c h , P o u l t r y S c i . , 45, 1071 ( 1 9 6 6 ) . ( 5 0 ) T. S. Chang, H. E. B u t t e r s , and C. A. Johnson, P o u l t r y S c i . , 4 5, 1076 ( 1 9 6 6 ) . ( 5 1 ) R. L. L o t t , P o u l t r y S c i . , 1099 ( 1 9 6 6 ) . ( 5 2 ) N. N i k o l a i c z u k , P o u l t r y S c i . , 45, 1110 ( 1 9 6 6 ) . ( 5 3 ) J . F. S t e p h e n s , B. D. B a r n e t t , and H. E. B u t t e r s , P o u l t r y S c i . , 4 5 , 1127 ( 1966). ( 5 4 ) R. N. B r e w e r and W. M. Reid, P o u l t r y S c i . , 45, 1072 ( 1 9 6 6 ) . ( 5 5 ) I m p e r i a l Chemical I n d u s t r i e s , L t d . , B e l g i a n P a t e n t 677,592. ( 5 6 ) B. L. S t o c k , G. T. Stephenson, and T. A. H y m a s , P o u l t r y S c i . , 4 5, 1127 ( 1 9 6 6 ) . ( 5 7 ) W. M. Reid and R. N. B r w e r , P o u l t r y S c i . , 45, 1118 ( 1 9 6 6 ) . ( 5 8 ) R. R. Baron, M. W. Moeller and N. F. M o r e h o z e , P o u l t r y S c i . , 45, 411 ( 1 9 6 6 ) .
13,
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157
Chapter 15. Antiflmgal Agents Robert B. Angier Lederle Laboratories, American Cyanamid Co., P e a r l River, New York The many publications i n t h i s a r e a during 1966 have covered both t h e elaboration and v e r i f i c a t i o n of t h e usefulness of previously known d r u g s and t h e announcement of new compounds with p o t e n t i a l l y i n t e r e s t i n g a c t i v i t y . Considerable e f f o r t has a l s o been given t o t h e study of t h e mode of a c t i o n of various antifungal a n t i b i o t i c s . The m a t e r i a l i n t h i s chapter i s divided p r i m a r i l y i n t o sections on polyene a n t i b i o t i c s , nonpolyene a n t i b i o t i c s and s y n t h e t i c compounds. Polyene Antibiotics--This c l a s s of compounds i s of considerable usef i l n e s s , primarily f o r t h e treatment of systemic mycoses and conditions caused by various species of Candida. C l i n i c a l r e p o r t s on t h e c u r a t i v e e f f e c t of amphotericin B continue t o appear. They include i t s successfbl use i n t h e follow'n systemic coccidioidomycoses, cryptococfungal diseases : blastomycosis c ~ s i s , 7~ Candida , endocarditis,s Candida meningitis, 9 meningitis due t o Sporotrichum schenkii,1° and histoplasmosis.l1j l2 A new t h e r a p e u t i c approach involving adjustment of t h e dosage of t h i s a n t i b i o t i c with regard t o t h e p a t i e n t ' s r e n a l f'unction and t h e serum l e v e l of t h e hase allowed t h e use of smaller doses than those generally recommended complete s t r u c t u r e of amphotericin B i s s t i l l unsolved. However, one report14 suggests t h a t a p a r t i a l s t r u c t u r e f o r amphotericin ,B aglycone can be formulated as 1. Further work i s necessary t o determine t h e comp l e t e oxygenation p a t t e r n and t h e p o s i t i o n o f attachment of t h e mycosamine moiety t o t h e aglycone. A second r e p o r t suggests a s i m i l a r s t r u c t u r e i n less detail.15 A timely review a r t i c l e 1 6 covers t o x i c i t y , mechanism of a c t i o n and therap e u t i c usefulness of anrphotericin B.
*,
t,9
dryj
I Nystatin has been found t o be a s a t i s f a c t o r y drug f o r the treatment of vaginal moniliasis i n nonpregnant women17 while i n o r a l candidiasis i t s sodium s a l t i n t h e form of an aerosol w a s reported t o be e f f i c a c i o u s . 18 A c l i n i c a l t r i a l involving 355 p a t i e n t s w i t h various skin ailments has delineated t h e usef'ulness of a l o t i o n containing pimaricin, -- neomycin
Sect. 111 - Chemotherapeutics
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Cheney, Ed.
and hydrocortisone. A general cure-rate of 7& w a s seen.lg Several other c l i n i c a l t r i a l s have shown pimaricin t o be u s e f u l p a r t i c u l a r l y i n vaginal rnoniliasisa,21,*2 and a review a r t i c l e has ap-pEared. 23 A corrected s t r u c t u r e f o r pimaricin has been reported while lucensomycin (111) w a s found t o be a homolog.
11; R = HH 3
c
a
cH3
111; R = z - C H 2 C H 2 C H 2 T
H
h 2
..
The r e l a t i v e l y new a n t i b i o t i c , c a n h* .c '@ i has given excellent results i n the t r e a a e n t of v a g i n a l m o n i l i a s l s and f a i r r e s u l t s with cutaneous moniliasis27 but good comparative tudies with previously known antifungal agents have not been reported. 28 Hamycin, used f o r the treatment of 30 p a t i e n t s with proven vaginal moniliasis, produced cures i n 29 p a t i e n t s and was considered t o be an outstanding drug for the treatment of t h i s d i ~ e a s e . ~ 9I n contrast t o t h i s i t s use i n 10 cases of systemic mycoses r e s u l t e d i n improvement i n only two cases.30 A question has been r a i s e d as t o t h e possible ident y, or a t l e a s t close s i & l a r i t y of hamycin, trichomycin and candicidin.
$1
The mode of action of polyene a n t i b i o t i c s has been t h e 1 9 6 among which a r e t h r e e review a r t i c l e s number of r e p o r t s ' The general theory i s t h a t these a n t i b i o t i c s cause a change i n t h e permea b i l i t y of the fungal c e l l membrane with attendant depletion of e s s e n t i a l c e l l u l a r constituents and that t h i s change i n permeability i s i n sane way t r i g g e r e d by a binding of the a n t i b i o t i c t o the c e l l membrane via a s t e r o i d - a n t i b i o t i c complex. Further support for t h i s theory, whicii&i e f f e c t says t h a t t h e presence of a s t e r o i d i n the c e l l membrane i s indeed a neeessary p r e r e q u i s i t e f o r polyene s e n s i t i v i t y , came as the r e s u l t of an i n v i t r o examination of t h e e f f e c t s of polyene a n t i b i o t i c s on mod3$ b i l a y G membrane systems of egg lecithin, with and without cholesterol. E a r l i e r s t u d i e s had shown t h a t added s t e r o i d s could prevent the antif'ungal a c t i v i t y of sane polyene a n t ' b i o t i c s possibly by complexing w i t h t h e a n t i b i o t i c . A more recent sku& k using Candida albicans has now shown t h a t wide differences exist among these a n t i b i o t i c s with reference t o t h e v a r i e t y of added s t e r o i d s which w i l l i n t e r f e r e with antif"Iga1
Antifungal Agents
Chap. 15
Angier
159 -
a c t i v i t y . I n addition a similar variation e x i s t s i n the b i l i t y of various a n t i b i o t i c s t o i n i t i a t e rapid loss of potassium ion. 38, Nonpolyene Antibiotics--The mode of action of griseofulvin (IV), a subject r e l a t i v e l y eglected i n the past, i s now receiving attention. It has been t h a t t h i s a n t i b i o t i c i n t e r f e r e s w i t h the replication mechanism of f'ungal c e l l s . However, a review a r t i c l e 3 9 indicates t h a t des p i t e the rather large mount of recent work there i s a t present no clear answer t o % h i s question. Several studies on the metabolism of griseofult two major metabolites, 6- and bdemethylgriseovin show t h a t i n the fulvin, are produced, ' j f i l wh'le i n the r a b b i t the only primary metabolite i s t h e 6-demethyl derivative. 2;1 pEthoxyacetanilide and p-metho benzylamine were found t o i n h i b i t t h i s metabolism i n rat l i v e r slices." An investigation of the origin of 0-methyl groups i n griseofulvin using I4Cl a b e l l e d substrates revealed t h a t pyruvic a c i serine, and formic acid supplied carbon t o a l l three methoxyl groups. $3
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An evaluation of microcrystalline griseofulvin therapy ( o r a l ) i n scalp ringworm using 324 p a t i e n t s emphasizes t h a t successful therapy requires d i f f e r e n t treatment schedules f o r nonfluorescent Tachophyton induced infections and those caused by Microsporum species. lth95 griseof'ulvin ( I V ) i s usually given o r a l l y ( a s above) a recentAreport discloses successful t o p i c a l treatment of 29 cases of s u p e r f i c i a l dermatcphytosis w i t h a 5% griseofulvin ointment. A ring-B carbon analog of
significant antifungal activity.
m
riseofulvin was synthesized but had no
V
A structure-activity study of g & l l & e x i d e (V), i t s derivatives and analogs using Saccharomyces pastorianus suggested t h a t keto, hydroxyl, and imide nitrogen groups may b involved i n a 3-point attachment of antibiot i c t o t h e sight of action.E7 The inhibitory e f f e c t s of cycloheximide i n yeast, algae, and mammalian c e l l s seem t o resemble one another i n t h a t i n each case the primary e f f e c t i s an i n h i b i t i o n of p r o g i n synthesis, whereas i n h i b i t i o n of nucleic acid synthesis i s indirect.
The polypeptide a n t i f b g a l agent, X-507 C, used i n 39 patients, w a s active ag i t North American b l a s t o m y c o d s t o p l a m o s i s , and sporctrichosis'gp*b t under the drug regimen t h a t was used the relapse r a t e was r a t h e r high. t 9
Sect. 111 - Chemotherapeutics
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Cheney, Ed.
Variotin, f o r which a d e t a i l e d s t r u c t u r e (VI) has now been reported,5O has been used i n the form of an ointment t o t r e a t 72 p a t i e n t s with ringworm infections caused primarily by T. rubrum and T. mentagrophytes. The r e s u l t s , 43 cured and 1 with improved conditions, suggest t h a t f’ut h e r t r i a l s a r e warranted.5
1
/CH3 H
‘C=C
C’‘
0
VI
Preliminary data indicate t h a t the following a n t i b i o t i c may be pot e n t ’ a l l y userul: r o l n i t r i n , 5 2 c-1 from c. vincetoxicum,53 necrotox, frenolicin, 57 and rufochromomycin. 58 in, 5 sporaviridin, f ~ o p h i o b o l o s i n56
t
Synthetic Antifungal Agents--Probably the most i n t e r e s t i n g of the antif‘ungal agents developed during t h e l a s t few years i s t o l n a f t a t e (VII). C l i n i c a l t r i a l s reported during 1966 have continued t o show t h a t t h i s compound i s a highly e f f e c t i v e and extremely well tolerated59 speci i c ag n t i n t h e treatment of s u p e r f i c i a l mycoses caused by d e r m a t o p h y t e ~ . ~ ~ , ~ l ~ & ~ , ~ 3 It i s noteworthy, however, t h a t t o cases of t i n e a n i g r a caused by Cladosporium wernecki were not cured.61: A teratogenesis study indicated t h a t t o l n a f t a t e does not adversely a f f e c t r a t or mouse f e t a l and p o s t n a t a l development .65
VII
VIII
Several c l i n i c a l studies66,67,68 with thiabendazole (VIII), a broadspectrum systemic anthelmintic, have shown it t o be p o t e n t i a l l y u s e m i n s u p e r f i c i a l f u n g u s i n ections of he skin, p a r t i c u l a r l y dermatophytic inf e c t i o n s of t h e groin86 and feet.ji7 Cutaneous moniliasis i s not aff cted.66 A s t r u c t u r e - a c t i v i t y study on sixty-eight 8-hydroxyquinolines 9 l e d t o the s e l e c t i o n of 5,7-dichloro-8-nicotinoyloxyquinoline as the most active compound. The l a t t e r compound w a s t e s t e d i n 24 p a t i e n t s with mycoses caused by trichophyton species. Total recovery of 14 p a t i e n t s and marked improvement i n 4 w a s reported.@ An ointment containing broxyquinoline ( I X ) and brobenzoxalidine ( X ) ( an i n t e s t i n a l a n t i s e p t i c and f’ungicide) showed promise i n t h e treatment of s u p e r f i c i a l mycoses of the skin.TO Topical t r e a h e n t of 398 p a t i e n t s gave improvement i n 8& of the 10 days l l g had cleared and a f t e r ll 21 cases as follows: a f t e r 7 days another 209 had cleared.
8
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Antifungal Agents
Chap. 15
+Angier
Br
Br
'4
161 -
C H 3
a
IX
x
A regimen of treatment f o r ringworm of the n a i l s which included the use of a 3C$ pyrogallol plaster, 1 : ; tetramethylthiuram diSulfi.de and 1% dimethylaurylbenzylaxnonium chloride appears t o have been highly successful. In 5 0 p a t i e n t s with 283 infected n a i l s $$ of the finger nails and 91% of the toe n a i l s were cured.71 The relapse or reinfection r a t e was 12-14$. A rapid, single, overnight treatment of t i n e a versicolor w i t h a 2.5$ selenium sulfide suspension appears t o be useful despite a rather high recurrence rate. O a t of 98 p a t i e n t s 81 shared complete elimination of the €Ungus while another 9 showed marked improvement.72
Although not generally appreciated polynoxylin (polyoxymethyleneurea) appears t o be userul i n the treatment of o r a l candidiasis. O f twenty-four cases t r e a t e d with polynoxy n lozenges for one month 17 were cured and the other 7 showed improvement.$3 Among a group of 200 cases of vaginal infection of various kinds t r e a t e d w i t h a preparation containing 1$ O-iodcbenzoic acid and ll$ triethanolamine 15 p a t i e n t s with vaginal monoliasis gave r e s u l t s r a t e d as good t o excellent i n 95% of the cases.74 The t r e a t ment o f 150 cases of monilial skin infections with a cream containing 0.15 penotrane (phenyhercury 2,2'-dinaphthylmethane-3,3 '-disulfonate) and 0.25; prednisolone resulted i clearing of the infection i n 75$ of the cases and improvement i n l.5$.q5 No s e n s i t i v i t y reactions were observed. Subcutaneous phycomycosis, a tumor associated with the f'ungus Basidiobolus haposporus or B. meristosporus, appears t o be susceptible t o treatment with potassium iodide. O f 12 cases seen 5 of them could b t r e a t e d regularly w i t h potassium iodide and a l l of these r e ~ o v e r e d . ~Pre~ vious attempts t o t r e a t other cases with nystatin or griseorulvin had been unsuccessful. 11-Iodo-10-undecylenic acid i s claimed t o be superior t o 10-undecyl e n i c acid f o r the treatment of a dernatophytosis of the skin of guinea pigs caused by trichophyton species.77 The iodo derivative i n a 1% solut i o n gave an 821, cure while undecylenic acid i n a 1 6 solution gave only a 23% cure.
4An i n v i t r o structure-activity study of 34 simple derivatives of thiocyanatoaniline was carried out using 8 dermatophytes (3 genera). One ccanpound, 2,5-dichlorc-4-thiocyanatoaniline, was found t o be active topi-
Sect. 111 - Chemotherapeutics
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Cheney, Ed.
tally i n guinea pigs but i n man it produced skin s e n s i t i ~ a t i o n . 7 ~The
authors comment on t h e inadequacy of animal t e s t s t o detect compounds causing s e n s i t i z a t i o n reactions i n man. I n Vitro Synthetics--Many compounds a r e regularly claimed, with varying degrees of documentation t o have -i n v i t r o antif'ungal a c t i v i t y . The following canpounds and groups of compounds were s e l e c t e d as of i n t e r e s t on t h e basis of t h e degree, v a r i e t y and r e l i a b i l i t y of documented a c t i v i t y : basically-substituted e t h e r s f benzothiazole,79 ar 1- and aralkylthiocyanates and isothiocyanates,80 1,3-b nzoxathioles,61 1,2-benz2, h-bis( arylamino isothiazolone 82 N-dichloroio osalicylanilides, pyrimidines,8$' dehydroemetine, 85 3,3 '-dihydroxy-a, 1,3-bis( 2-~hloroethyl)-l-nitrosourea,~~ n i t r o f b r a n derivatives, 2-brmo-3-phen 1-2-propenal,9l 2-hydroxythiobenzamides g2 1,3,5-thiadiazin-2-thiones,% carbonyl- and thiocarbamoyldisulfides, g4 cinnamylidene derivatives of
&
8
Test Method--A technique has been described f o r t h e -i n v i t r o screening of 1- e numbers of compounds f o r antif'ungal and/or a n t i b a c t e r i a l prop e r t i e s . lo$It involves t h e use of small tubes containing only 0.5 m l of medium and has been checked out with known antif'ungal agents. I t s advantages as a screening procedure are described. 102 Severa e n e r a l reviews have appeared within t h e l a s t two years .I032 lo$, fO5 References
8.
R. S. Abernathy, Abstr. Antimicrobial Agents Chemother. 1966, p. 37. J. P. Utz, Am. Rev. Resp. D i s . , 495 (1966). R. L. Rainey and T. R. H a r r i s , Arch. Internal. Med., 744 (1966). W. A. W i n n , Am. Rev. Resp. D i s . , 94, 496 (1966). W, Ziering and H. Rockas, Ibid, 93, 661 (1966). R. L. S t i r r e t , C a l i f . Med., l04,T13 (1966). J. E. Bennett, Abstr. Antimi=bial Agents Chemother. 1966, p. 79-80. J. G. Prinsloo and P. J. Pretorius, Mer. J. D i s . Child., lll, 446
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E. Borowski, W. Mechlinski, L. Falkarski, T. Ziminski, and J. D. Dutcher, Rocznicki Chem., %, 61 (1967). 16. W. T. Butler, J. Am. Med. Assoc., 195, 371 (1966). 17. H. I. Kantor, J. H. Kamkolz, and S . H. Boulas, Southern Med. J.,
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535 S. I. Pshbel, I. A. Bogoslovskaya, and V. G. Sokolova, Terapevt. Arkh.,
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H. Fueller, Med. JTelt, 607. M. Matsushita, M. Yuasa, M. Imamura, and H. Sakamoto, J. Antibiotics Tokyo, Ser. P., 19, 240 (1966). S. Mizuno and S. Matsuda, Chemotherapy, &, 142 (1966). G. Bernard and M. A. Jercune, Can. Med. Assoc. J., 2, 215 (1966). J. M. Bond i n "Experimental Chemotherapy" (R. J. Schnitzer and F. Hawking, eds.), Vol. 4, Academic Press, N. York, 1966, p. 573. B. T. Golding, R. W. Rickards, W. E. Meyer, J. B. Patrick, and M. Barber, Tetrahedron Letters, 1966, 3551. G. Gaudiano, P. Bravo, P. Quilico, T. B. Golding, and R. W. Rickards, 3567. Ibid, S. W. Giorlando, Clin. Med., 73, 33 (1966). L. A. Dick, Current Therap. Res., 7, 345 (1966). J. Am. Med. Assoc., 128 (196q. A. Alverez-Bravo, R. Quiroz, E. Vazquez, and M. Gonzales-Ramos, Antimicrobial Agents Chemother. 1965, p. 706 (1966). E. Rothstein, An. Rev. Resp. D i s . , 94,642 (1966). P. V. Divekar, V. C. Vora, and A. F!. Khan, J. Antibiotics Tokyo, Ser. A, 9, 63 (1966). S. C. Kinsky, S. A. Luse, and L. L. M. van Deenen, Fed. Proc., 25, 1503 (1966)J. 0. Lampen, W. L. McLellan, Jr., and M. A. El-Nakeeb, Antimicrobial Agents Chemother. 1965, 1006 (1966). J. 0. Lampen, S y m p x c . Gen. Microbiol., 16, 111 (1966). H. van Zutphen, L. L. M. van Deenen, and C ..S Kinsky, Biochem. Biophys. Res. Cammun., 22, 393 (1966). W. A. Zygmunt, Appl. Microbiol., 1 4 865 (1966). 17. A. Zygmunt, Ibid., 953 F. M. Huber, Dissert-Abstr., 26, 7009 (1966). K. J. Bent and R. H. Moore, Symp. SOC. Gen. Microbiol., 16, 82 (1966). S. dymchowicz and K. K. Wong, Biochem. Pharmacol., 15, 1 , l(1966). M. Schofield, K. K. Wong, S. Symchowicz, and I. I. A. Tabachnick, Fed. Proc. (Abs.) 25, abs. 1294 (1966). S. A. Kaplan,?. Riegelman, and K. H. Lee, J. Pharm. Sci., 55, 14
43 44. 45.
V. Behal, F o l i a Microbiol., 2, 184 (1966). N. Zaias, D. Taplin, and G. Rebell, J. Am. Med. ASSOC., I $ ,805 (1966). E. Friedrich, E. Brandt, K. Borchardt, and J. Krause, Hautarzt.,
19 20. 21. 22. 23
24. 25
26. 27 28.
29. 30
31. 32.
33
34. 35
9
36 37. 38. 39. 40.
41.
-
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196,
14,
(1-j.
(1966)
9
46. 47.
48.
49
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368 (1966).
H. Newman and R. B. Angier, J. Org. Chem., 31, 1462 (1966). M. R. Siegel, H, D, S i s l e r , and F. Johnson, Biochem. Pharmacol., 1213 (1966). I. Morris, Nature, 211, 119 (1966). P. Witorsch, V. T. Andriole, C. FJ. ESrrmons, and J. P. Utz, Pm. Rev.
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Resp. D i s . , 93, 876 (1966). J. J. Procknow, Ibid, 94, 761 (1966). S. Takeuchi and H. YonZThara, Tetrahedron Letters, 5197. G. Holti, A. Lyell, D. I. McCallum, J. K. Morgan, and P. A. J. Smith, B r i t . J. Derm., 7 ' 8, 661 (1966). M. Nishida, T. Matsubm, and N. Watanabe, J. Antibiotics Tokyo, Ser. A., 211 (1965). L. Ferenczy, J. Zsolt, A. Haznagy, L. Toth, and K. Szendrei, Acta Microbiol. Acad. Sci. Hung., l2, 337 (1966). V. H. Pawar, P. V. Deshmukh, and M. J. Thirumalacher, Hindustan Antib i o t . B u l l . , 8, 59 (1965). T. Okuda, Y. ?to, T. Yaaguchi, T. Furumai, M. Suzuki, and M. Tsuruoka, J. Antibiotics Tokyo, Ser. A., 9, 85 (1966). H. Ohkawa and T. Tamura, ,Agr. Biol. Chem., 30, 285 (1966). G. A. E l l e s t a d H. A. Whaley, and E. L. Patterson, J. Am. Chem. Soc.,
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53
54. 55 56 57.
5960. 61. 62. 63 64.
2,
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J. Jacquet, F. L e t e l l i e r , P. Jacob, and S. fi.bbatucci, Compt. Rend. SOC. Biol., 160, 241 (1966). Y. Hashimoto, T. Noguchi, H. Kitagawa, and G. Ohta, Toxicol. Appl. Pharmacol., S, 380 (1966). D. E. Hackbarth and L. S . Markson, Current TherapRes., 8, 175 (1966). A. H. Gould, South. Med. J., 59, 176 (1966). J. Alban, Amer. J. D i s . Child., 110, 624 (1965). H. Johne, Med. Uelt., 1966, 17717 W. 3 . Miles, kl. T. Branom, and S. B. Frank, Arch. Dermatol., 203
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65 T. Tanirmrra, Toxicol. Appl. Pharmacol., g, 386 (1966). 66. R. Fleischmajer, J. Goldstein, and L. Nicholas, Current Therap. Res., -7, 558 (1965). 67. A. M. Kligaan, J. Am. Med. Assoc., 193, 923 (1965). 68. 0. J. Stone, E. B. Ritchie, and C. J. ' d i l l i s , Arch. Dermatol., e2, 241 (1966). 69. H. Fiedler and U. Kaben, Pharmazie, 2l, 233 (1966). 20, 331 (1966). 70 H. I:eitgasser, Z. Haut-Geschlectskrankh, 71 J. Kejda, Hautarzt, l7, 429 (1966). 72 S. D. Albright, I11 and J. M. Hitch, Arch. Dermatol., 93, 460 (1966). 73* S. Kennett and L. Cohen, B r i t . Med. J., 1966, 1200. 74 R. E. L. Gowan, Clin. Med., 73, 91 ( 1 9 6 r 75 G. H. Ritterman, P r a c t i t i o n e r , 196, 419 (1966). 76 T. H. Tio M. Djojopranoto and N. I. T. Eng., Arch. Dermatol., 93, 550 (1966). 77 A. Ueno, E. Matsusaki, K. Momoki, G. Saito, and S. Sakai, Japanese Patent 19,406, Dement Basic 23,993. 78 B. Croshaw, J. S. Davidson and D. F. Spooner, J. Pharm. Pharmacol., 18, 739 (1966). 79 H. D. Cossey, R. N. Gartside and F. F. Stephans, Przneimittelforsch., 16, 33 (1966). 80. Von T. Zsolnai, Ibid., l6, 870 (1966). 81. H. Fiedler and U. Kaben, Pharmazie, 2, 178 (1966). 82. R. Ponci, P.. Baruffini, and P. Borgna, Farmaco, Sci. Ed., 2, 249 (1966). 9
Chap. 1 5
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Angier
83 84. 85 86. 87
S. D. H. D. D.
S. Stavs'ka, Fed. Proc., 25, p t . 2, 710 (1966). Ghosh, J. Med. Chem., 2, 423 (1966). Abd-Rabbo and H. M. Yusef, J. Trop. Med. Hygiene, 69, 51 (1966). Adam and H. Schoenenberger, Arzneimittelforsch., 738 (1966). E. H u n t and R. F. P i t t i l o , Antimicrobial Agents Chemother. 1965,
88. 89
P. A. A. T.
710 (1966).
90
91 92
93 94
9
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96, 97 g8 99 100. 101. 102. 103.
104. 105.
86,
&
Sugihara, J. Pharm. Soc. Japan, 86, 349 (1966). Sugiharra, I b i d , 86, 269 (1966). Anmo, H. HayashiTS. Kouchiwa and T. Nagayoshi, Yakugaku Zasshi,
735 (1966).
A. R. Torres, Therapie, 21, 473 W. Weufen, G. Wagner, D.Singer,
(xm. L. Krempl-Lamprecht,
(1966). and M, Petermann, Pharraazie,
21,
Mykosen, 2, 11 (1966). J. D. Buckman, B. S. Johnson, and L. Field, Can. J. Microbiol.,
613
12,
1263 (1966). B r i t i s h Patent 1,048,936; Dement Basic 23,864. French P a t e n t 996,892; Dement Basic 23,419. Belgium Patent 671,511; Dement Basic 20,830. A. S. Tomcufcik, J. M. Craig, and S. D. 'iziillson, U.S. Patent 3,284,453. Belgium Patent 671,528; Dement Basic 20,831. L. F. Marnett, R. J. Tenney, and J. B. Thompson, U.S. P a t e n t 3,275,503. W. Weuffen, Pharmazie, 21, 686 (1966). P. Catalfomo and H. W. Schultz, J. Pharm. Sci., 55, 117 (1966). ( a ) R. Brown i n "Experimental Chemotherapy" (R. J. Schnitzer and F. Hawking, eds), V o l . 3, fcademic Press, New York, 1964, p. 418; ( b ) P. H. Campbell, Ibid., p. 461. L. A. S c i u c h e t t i , Pharmindex, 7, 4 (1965). A. M. Arievich, Zh. Vses. Khin; Obshchestva i n D. I. Mendeleeva,
10,
658 (1965).
Chapter 16 Antineoplastic Agents C h a r l e s W . Young and David A . Karnofsky Sloan-Kettering Institute, New York, N . Y . Introduction - R e s e a r c h on antineoplastic agents follows an o r d e r l y s e quence. D r u g s which exhibit antitumor activity in a n i m a l s bearing t r a n s planted n e o p l a s m s or cytotoxicity in c e l l c u l t u r e s a r e c o n s i d e r e d for f u r ther study. These c h e m i c a l s a r e examined with r e s p e c t to toxicology, e f f e c t s upon r e s i s t a n t t u m o r s , and biochemical m e c h a n i s m of action. The animal tumor s c r e e n continues in use in spite of widespread doubt as t o its efficacy b e c a u s e no b e t t e r method to s e l e c t d r u g s f o r clinical t r i a l against c a n c e r h a s been found. Recently, Goldin, e t al. have reviewed the r e s u l t s obtained in the s c r e e n i n g s y s t e m of the C a n c e r Chemotherapy National S e r v i c e C e n t e r and suggested potentially useful simplifications; 1 F r e i r e i c h , e t al. have examined the predictive utility of p r e c l i n i c a l toxicology with r e s p e c t to anticancer a g e n t s ; 2 and Zubrod and c o w o r k e r s have analyzed the chemotherapy p r o g r a m of the National C a n c e r Institute.3
--
--
D r u g s which show c o n s i s t e n t antitumor activity in p r e - c l i n i c a l studies a r e evaluated for therapeutic effects against v a r i o u s f o r m s of c a n c e r in m a n . P u r i n e and P y r i m i d i n e Analogues - The following c o m m e n t s w i l l c e n t e r upon work published in 1966; Heidelberger h a s included e a r l i e r work in this a r e a in h i s r e c e n t review. Modifications of 6-mercaptopurine (I) a r e of continuing i n t e r e s t because of m e r c a p t o p u r i n e ' s activity in human l e u k e m i a , and the ultimate development of r e s i s t a n c e by the leukemic c e l l s t o this d r u g . 6-methylmercaptopurine r i b o s i d e (11) i s converted t o 6-methylmercaptopur ine ribonucleotide (111) by a nucleoside kinase. C e l l s that have l o s t inosinic pyrophosRl R2 p h o r y l a s e , a m e c h a n i s m whereby I H H they became r e s i s t a n t to I , a r e ' I CH3 ribose still inhibited by 11. Bennett h a s $T 'I1 CH3 r i b o s e d e m o n s t r a t e d the p r e s e n c e of 111 PO4 in c e l l s exposed to I and suggested R2 that p a r t of inhibitory effect of I m a y be mediated i n p a r t through i t s conversion to III;5 a s y n e r g i s m between the antitumor e f f e c t s of I and I1 h a s been r e p o r t e d in m i c e bearing Ehrlich ascites tumor. 6
fj-(N>
The limited therapeutic activity of the fluorinated p y r i m i d i n e s 5 f l u o r o u r a c i l ( F U ) and 5-fluoro-Zf-deoxyuridine(FUdR) in c e r t a i n f o r m s of adenocarcinoma, principally of the digestive t r a c t , have led to the synt h e s i s of a v a r i e t y of analogues. Dinucleoside phosphates containing F U
Chap. 16
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Young and Karnofsky
167 -
r e s i d u e s have been produced i n the hope that they would be cleaved i n t r a c e l l u l a r l y thus generating the corresponding r i b o - or deoxyribonucleotide The concept i s without r e c o u r s e t o a nucleoside kinase r e a c t i o n . p e r t i n e n t since l o s s , o r l a c k , of e n z y m e s in the pyrimidine salvage pathway i s one potential m e c h a n i s m of tumor r e s i s t a n c e t o F U o r FUdR. Since p-5 -fluoro-Z-deoxyuridylyl-(5'- 5 ' ) - p - 5 -fluorodeoxyuridine did not inhibit growth of E h r l i c h a s c i t e s tumor c e l l s r e s i s t a n t to FUdR, 7 the aforementioned hope h a s not been r e a l i z e d . A s e r i e s of 5-halo-6-oxydihydro d e r i v a t i v e s of the fluorinated p y r i m i d i n e s h a s proven r e s i s t a n t to enzymatic degradation in a n i m a l s ; by sponR = deoxytaneous r e g e n e r a t i o n of the 5-6 double bond, ribose F U o r FUdR i s r e l e a s e d over a prolonged period of t i m e . 9 One of these analogues, H"< 3 i H 3 0 IV 5 -bromo-6-methoxydihydro-5 -fluoro-2' R deoxyuridine (IV), h a s been active against colon c a n c e r in a p r e l i m i n a r y c l i n i c a l t r i a l but h a s not been found to p o s s e s s any advantage over F U . J
1-p-D-arabinofuranosyl cytosine ( a r a - C , cytosine arabinoside ( V ) i s a synthetic nucleoside analogue with antitumor and antivir a1 a c t i v i t i e s ; the p r e c l i n i c a l studies on t h i s compound have been reviewed by Smith. A r a - C is active i n the t r e a t m e n t of acute leukemia. l 2 T h i s agent p r o d u c e s cytotoxic and therapeutic effects by Rl R2 inhibiting s y n t h e s i s of DNA; a nucleoR1 v H a r a b i n o s e tide metabolite of a r a - C i m p e d e s O.i, VI F a r a b i n o s e c o n v e r s i o n of cytidylate to deoxycytidylate thus depleting c e l l u l a r pools I of t h i s DNA constituent. The r e c e n t R2 demonstration that m e t a b o l i t e s of ar a-C m a y be i n c o r p o r a t e d into DNA or RNA m a y a l s o be p e r t i n e n t to the d r u g ' s cytotoxicity. 139 14 Insensitivity or r e s i s t a n c e t o the toxic e f f e c t s of a r a - C h a s been c o r r e l a t e d with the absence of (or l o s s of) deoxycytidine k i n a s e , l 4 Ara-C i s rapidly d e a m i n ated to a r a - U which l a c k s cytotoxic activity; t h i s deamination c a n be i n hibited by r e p l a c e m e n t of the 4-NH2 with -NHOH, -NHCH3, -NHNH2, o r -NHAc 15 o r by methylation on the 5 position. l 6 Such substitutions a l t e r r a t e s of degradation in vivo but have not produced an i n c r e a s e in t h e r a peutic index. 1 -p-D-arabinofur anosyl-5 -fluor ocytosine (ar a - F C ) (VI) was synthesized in the hope that i t might combine the inhibitory effects of both a r a - C and FUdR. 17 A r a - F C h a s proved to be identical in its biologic activity t o a r a - C i n p r e c l i n i c a l s t u d i e s . l8
5
Antibiotics with Antineoplastic Activity - A number of tumor -inhibitory antibiotics f o r m stable complexes with DNA thereby i n t e r f e r i n g with synt h e s i s of RNA. T h r e e of t h e s e antibiotics, actinomycin, m i t h r a m y c i n and daunomycin (which i s probably identical to rubidomycin) p o s s e s s
Sect. I11
168 -
-
Chemotherapeutic s
Cheney, Ed.
unequivocal activity against c a n c e r in m a n . K e r s t e n , K e r s t e n and Szybalski have s u m m a r i z e d the l i t e r a t u r e on the binding of a number of t h e s e antibiotics t o DNA and r e p o r t e d t h e i r own o b s e r v a t i o n s on the pbysic o c h e m i c a l p r o p e r t i e s of the complexes s o f o r m e d . 19 By chromophore g r o u p s t h e s e antibiotics c a n be divided into t h r e e c l a s s e s : actinomycins (VII), c h r o m o m y c i n s (VIII) including m i t h r a m y c i n and olivomycin, and the anthr acyclines (IX) which include daunomycin, c i n e r u b i n , nogalamycin
/ o CH3
R-R<./z3
R'
7
&&2
OCH3
'
0
(533
H36 VII
IX
' OH
OH
/ I
OH
0
k'
VIII
X
and a number of o t h e r s . The binding c h a r a c t e r i s t i c s of these antibiotics c a n be usefully c o m p a r e d with those of acridine dyes ( X ) . The a n t h r a c y c l i n e s and acridine d y e s a r e similar in that they i n t e r c a l a t e between base p a i r s in DNA; they differ in that the anthracycline-DNA complex i s stable w h e r e a s the a c r i d i n e s a r e displaced in solutions of high ionic strength. P r e s u m a b l y the aminosugar r e s i d u e s in the anthr acycline s a r e responsible f o r stabilization of the antibiotic-DNA complex. P h y s i o c o c h e m i c a l e v i dence of intercalation i s not s e e n in complexes of DNA with actinomycins or c h r o m o m y c i n s . Both actinomycins and anthracyclines c a u s e stabilization of native DNA to t h e r m a l denaturation; the anthracycline s a r e considerably m o r e effective in t h i s r e s p e c t on a m o l a r b a s i s while c h r o m o mycin antibiotics a r e without e f f e c t . The effect of the antibiotic-DNA complex upon t h e r m a l denaturation s e e m s p e r t i n e n t t o some a s p e c t s of the d r u g s biological e f f e c t s on c e l l s . S e p a r a t i o n of s t r a n d s of DNA is a p r e s u m e d p r e r e q u i s i t e f o r their replication; an antibiotic complex which i n t e r f e r e s with this splitting would inhibit DNA s y n t h e s i s . Mithramycin h a s no effect upon t h e r m a l stability of DNA and no acute effect upon DNA s y n t h e s i s a t concentrations which inhibit s y n t h e s i s of RNA. 2 o The a n t h r a c y c l i n e s enhance the t h e r m a l stability of DNA to a g r e a t e r extent than do the actinomycins; the f o r m e r a r e a l s o l e s s selective i n their inhibitory effects on s y n t h e s i s of nucleic a c i d s . 2 1 The relationship of binding of
Chap. 16
Antineoplastic s
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t h e s e antibiotics to the b a s e composition of DNA h a s been examined by m e a n s of s p e c t r a l shift, change i n melting p r o f i l e , inhibition of RNA polym e r a s e and the change i n buoyant density i n a c e s i u m c h l o r i d e g r a d i e n t . The r e s u l t s obtained by v a r i o u s w o r k e r s employing these s e v e r a l t e c h niques a r e not in t o t a l a g r e e m e n t . It s e e m s c l e a r , h o w e v e r , that the p r e sence of deoxyguanosine r e s i d u e s i n DNA is r e q u i r e d for binding of Actinomycin D. Anthracyclines c a n complex with poly dAT and poly dGdC; however, binding of nogalamycin m a y be f a v o r e d by dAT p a i r s while that of daunomycin i s not. The p r e s e n c e of c a t i o n s ( M g t t or Cis' ) m a y play a r o l e in complex f o r m a t i o n between the c h r o m o m y c i n antibiotics and DNA. Extension of these c o m p a r i s o n s into i n t a c t c e l l s and i n t o c l i n i c a l pharmacology i s now becoming p o s s i b l e at l e a s t with r e s p e c t t o actinomycin D , daunomycin and m i t h r a m y c i n . Actinomycin D is the m o s t potent of the t h r e e d r u g s on a m o l a r b a s i s whether c o n s i d e r e d i n t e r m s of growth inhibition i n c e l l c u l t u r e , d e p r e s s i o n of RNA s y n t h e s i s or the u s u a l c l i n i c a l d o s a g e . In c e l l c u l t u r e s , actinomycin c a n produce acutely a l m o s t complete inhibition of RNA s y n t h e s i s ; t h i s d e g r e e of inhibition can not be achieved acutely with m i t h r amycin20 o r daunomycin. 2 2 The e x t r e m e sensitivity of nucleolar function and of the s y n t h e s i s of r i b o s o m a l RNA to the e f f e c t s of low c o n c e n t r a t i o n s of actinornycin D h a s again been e m p h a sized by ultr a s t r ~ c t u r a and l ~ ~u l t r a ~ e n t r i f u g a ol b ~s~e r v a t i o n s . Nucleolar morphology and the s y n t h e s i s of nucleolar RNA a l s o s e e m quite susceptible 2 5 The e x i s t e n c e of genetically functional to the e f f e c t s of daunomycin. DNA within mitochondria g i v e s i m p o r t a n c e to a r e p o r t that actinomycin D, m i t h r a m y c i n , rubidomycin and nogalamycin c a n e a c h i n t e r f e r e with the utilization of A T P g e n e r a t e d by oxidative phosphorylation in S a r c o m a 37 a s c i t e s c e l l s . 26 In c l i n i c a l t r i a l s , both actinomycin D and m i t h r a m y c i n a r e active in some p a t i e n t s with t e s t i c u l a r c a n c e r ; both d r u g s produce r e g r e s s i o n s in n e u r o b l a s t o m a . 27On the other hand, daunomycin i s active a g a i n s t acute l e u k e m i a while actinomycin s e e m s ineffective. 2 7 In their c l i n i c a l toxicology, the t h r e e d r u g s a r e s i m i l a r i n that they all produce bone m a r r o w hypoplasia. They differ i n that hepatic and r e n a l toxicity, hypocalcemia and h e m o r r h a g i c phenomena, the l a t t e r r e l a t e d to c a p i l l a r y injury and elevated p r o t h r o m b i n time, seem p e c u l i a r to m i t h r a m y c i n . 2 2 j
With the r e c e n t availability of 3H-actinomycin D a positive c o r r e l a tion h a s been r e p o r t e d between uptake28 and prolonged r e t e n t i o n 2 9 of the labeled d r u g ty tumor c e l l s and the sensitivity of those c e l l s t o the cytotoxic effects of the antibiotic. Recent r e p o r t s on a number of other antitumor antibiotics m e r i t mention because of t h e i r p e r t i n e n c e to the study of n o r m a l c e l l m e t a b o l i s m although the d r u g s i n question e i t h e r have little c l i n i c a l applicability o r a r e y e t to r e c e i v e adequate trial. Cycloheximide and r e l a t e d g l u t a r i m i d e
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antibiotics a r e receiving increasing use a s inhibitors of protein synthesis in y e a s t and mammalian c e l l s ; Vanek and Voncracek have presented a d e tailed description of their biogenesis in Streptomyces nour sei30 while Siegel, S i s l e r and Johnson have examined the relationship between s t r u c t u r e and fungitoxicity in Saccharomyces pastorianus. 3 1 Grollman has postulated an analogy between cycloheximides and emetine, and suggested a s t r u c t u r a l b a s i s for their inhibitory effects upon protein synthesis. 32 Pactamycin a l s o h a s proven to be an inhibitor of protein synthesis; differing in some r e s p e c t s both f r o m puromycin and the cycloheximide antibiotics. 3 3 , 3 4 Kajiwara and coworkers using synchronized c u l t u r e s of HeLa c e l l s have identified a point of inhibition of cellular proliferation by phleomycin following completion of DNA synthesis and p r i o r to prophase. 35 Vinca Alkaloids - Because of the clinical utility of vinblastine and vinc r i s t i n e in the t r e a t m e n t of some types of human cancer, other alkaloids similarly obtained f r o m Vinca r o s e a Linn. have been studied in experimental t u m o r s and in man. Vinleurosine, a dimeric indoline alkaloid, like vinblastine and vincristine, but c l e a r l y different f r o m them on physicochemical and chemical tests, received a therapeutic t r i a l in 42 patients with a variety of neoplasms. 36 Only one, a patient with Hodgkin's d i s e a s e , obtained clinical benefit; the majority of lymphomas and leukemias treated in this study were known to be r e s i s t a n t to vinblastine or vincristine. On the other hand, a clinically modified vinblastine, vinglycinate sulfate, desacetyl vinblastine 4 ( N , N-dimethyl-glycinate) sulfate, or VGL has produced beneficial r e s p o n s e s in Hodgkin's d i s e a s e , lymphosarcoma, bronchogenic carcinoma and chondrosarcoma. 37 Clinical improvement was obtained in s e v e r a l patients felt to be r e s i s t a n t to vinblastine and vincristine. The toxicity of VGL r e s e m b l e s that of vinblastine; leukopenia was dose limiting, neurotoxicity was not observed in the 31 patients studied. N o better explanation for the antitumor effects of the vinca alkaloids h a s been adduced than that of mitotic a r r e s t , o f f e r e d some y e a r s ago; further support for this mechanism has been obtained f r o m studies in patients with Hodgkin's d i s e a s e , lymphosarcoma, and acute leukemia. 38 On the other hand mitotic a r r e s t cannot account for the p e r i p h e r a l nerve injury commonly produced in patients by therapy with vincristine, nor for the inhibition of synthesis of DNA produced in regenerating r a t liver by vinblastine. 39 Studies continue upon the effects of the vinca alkaloids upon protein and nucleic acid metabolism in vitro. 40 The drug concentrations employed to produce inhibitory changes in these studies a r e so far beyond any that a r e achieved in vivo that the observations a r e of doubtful p e r t i nence to clinical effects. Asparaginase - L-asparagine amidohydrolase ( E . C . 3 . 5 . 1 . 1 ) inhibits growth of some murine lymphomas and leukemias; i t i s presently undergoing preliminary clinical t r i a l , In leukemic patients, a drug-associated
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decline in circulating leukemic c e l l s h a s been observed. 41 The antitumor activity of asparaginase was f i r s t described a s an unknown factor in guinea pig s e r u m by Kidd. 42 The identity of the guinea pig s e r u m factor w a s established a s asparaginase by Broome. 43 In clinical t r i a l s of a s paraginase an enzyme preparation f r o m E . coli i s being employed; this bacterium produces a t l e a s t two proteins with asparaginase activity only one of which is active in the mouse lymphoma a s s a y . 44 P r e s u m a b l y the enzyme is cytotoxic by reducing extracellular asparagine levels and thus intracellular asparagine in those c e l l populations which lack the enzyme to aminate a s p a r t i c acid. Asparagine dependence i s not uncommon in murine leukemias. 45 When studied in vivo the e a r l i e s t effect of a s p a r a ginase upon the sensitive murine lymphoma 6C3HED was finhibition of protein synthesis, a s manifest in d e c r e a s e d incorporation of 14C-valine into protein. 46 This occurred within minutes following administration of the enzyme; inhibitory effects upon synthesis of DNA were detected by 120 minutes while r a t e s of RNA synthesis began to f a l l only after 240 minutes. Extensive n e c r o s i s of tumor c e l l s was observed by 12 h o u r s following drug administration. The availability of an active preparation f r o m E. coli h a s permitted initial clinical t r i a l , however, the c u r r e n t preparation i s pyrogenic and antigenic. The r a t e of production of the enzyme in a clinically useful preparation is s t i l l too modest to p e r m i t an adequate clinical t r i a l . Mis c e llane ous Synthetic compound s - Pr oc ar bazine , ( N - i s opr opyl -a-(2 methy1hydrazino)-2- toluamide hydrochloride), one of sever a1 derivatives of methylhydr azine which have antineoplastic activity against transplanted t u m o r s , h a s proven clinically useful in the management of Hodgkin's d i s e a s e . A second derivative, N-allophanoyl-a-(2 methy1hydrazine)-ptoluamide, appeared to have activity comparable to that of procarbazine in a preliminary clinical trial. 47 The mechanism by which procarbazine and r e l a t e d compounds produce cytotoxicity is not established. P r o c a r b a z i n e produced a short-lived inhibition of synthesis of DNA, RNA and protein when studied in a mouse lymphoma;48 the methyl group e n t e r s the 1-carbon pool and participates in transmethylation reactions. 49 Pertinence of these observations, a s well a s those previously described of molecular autoxidation to the d r u g ' s antitumor effects, awaits demonstration. Because of the utility of 1, 3-bis(2-chloroethyl)- 1-nitrosourea (BCNU) (XI) in the study of experimental leukemia in mice a s well as because of i t s activity against human C1CH2CH2~C0NHCH2CH2C1 neoplasms, 5 o a s e r i e s of haloalkyl NO n i t r o s o u r e a s have been synthesized XI and tested against L-12 10 leukemia in mice. 5 1 In g e n e r a l the m o s t active compounds were 1-.[2-(chloro or f1uoro)ethyd -1-nitrosoureas substituted in the 3 position by a 2(chloro or f1uoro)ethyl or cycloaliphatic group.
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A s e r i e s of acetylenic c a r b a m a t e s have p r o v e n t o have potent a n t i tumor e f f e c t s against t r a n s p l a n t e d m u r i n e t u m o r s and t o be devoid of hypnotic proper tie^;^^ one of t h e s e , 1- 1-diphenyl-2-propynl cyclohexylcarbamate i s undergoing c l i n i c a l trial. In s t r u c t u r e - a c t i v i t y studies the a c e t ylenic group and a r o m a t i c 1, 1 substituents w e r e e s s e n t i a l f o r antitumor activity. P r o v i d e d t h a t the c a r b a m o y l n i t r o g e n had two substituents they could be v a r i e d widely. The p a i r i n g of cyclohexyl and H gave high potency. Investigation of h y d r o x y u r e a and r e l a t e d d e r i v a t i v e s h a s continued i n s p i t e of t h e i r l i m i t e d c l i n i c a l utility. T h a t h y d r o x y u r e a i s cytotoxic by r e a s o n of i t s inhibitory effects upon s y n t h e s i s of DNA,has been widely ~ cell-free extracts d e m o n s t r a t e d . R e c e n t o b s e r v a t i o n i n c e l l ~ u l t u r e 5and 54 have c o n f i r m e d p r e v i o u s r e p o r t s that the d r u g inhibits ribonucleotide r e d u c t i o n . A detailed morphologic a n a l y s i s of c e l l d a m a g e in r a t s t r e a t e d with h y d r o x y u r e a indicated t h a t l e t h a l e f f e c t s o c c u r r e d only i n those c e l l s synthesizing DNA at the t i m e of d r u g a d m i n i s t r a t i o n . 55 A v a r i e t y of h y d r o x y u r e a analogues have been t e s t e d i n t r a n s p l a n t e d t u m o r s y s t e m s ; 57 the 1-ethyl and 1-methyl d e r i v a t i v e s of h y d r o x y u r e a p o s s e s s antineoplastic activity equal to o r g r e a t e r than the p a r e n t compound. Oxamyl hydroxamic acid inhibited r a t e s of growth and DNA s y n t h e s i s i n E . coli and E h r l i c h a s c i t e s tumor r e s p e c t i v e l y i n a fashion quite c o m p a r a b l e to h y d r o x y u r e a but it a l s o produced significant methemoglobinemia which m i t i g a t e s a g a i n s t i t s c l i n i c a l u s e . 58 5 6 j
The t u m o r -inhibitory activity of analogues of p u r i n e and pyrimidine b a s e s led Shealy and s e v e r a l c o w o r k e r s to synthesize a s e r i e s of a n a logues of the i m i d a z o l e s i n the biosynthetic pathway to purine ribonucleot i d e s and to t e s t t h e s e analogues for antineoplastic e f f e c t s . 59 Beginning with 5 (or 4)-aminoimidazole-4 (or 5 ) - c a r b o x a i d e (AIC) (XII) or the a n a N FONH2 x=C H logue 5-amino-v-triazole-4-carboxXI11 X= N a m i d e (XIII) they produced d i a z o \ d e r i v a t i v e s (XIV) which r e a c t with H2 H secondary a m i n e s to produce t r i a z e n e s . A number of t h e s e t r i a z e n o d e r i v a t i v e s p o s s e s s antitumor a c t i v ity against t r a n s p l a n t e d c a n c e r i n XIV a n i m a l s ; one compound 5 -(dimethyl0 N tr iazeno)-imidazole -4-c ar boxamide N2 ( X V ) is undergoing c l i n i c a l t r i a l . Of CONH2 I 1 mono-substituted t r i a z e n o imixv x=C H dazole s t e s t e d , only 5 -me thyltriazeno XVI X = N imidazole -4-c a r boxamide w a s c o n s i s t e n t l y active against the mouse N = N-N(CH3)z H l e u k e m i a L-1210. Two of nine
A /!.IcoNH2
x/'
T
x\
47
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triazeno-v-triazole-4-carboxamide d e r i v a t i v e s w e r e a c t i v e a g a i n s t L- 12 10; the e f f e c t i v e n e s s of the d i m e t h y l d e r i v a t i v e (XVI) w a s roughly c o m p a r a b l e t o t h a t of the i m i d a z o l e d e r i v a t i v e (XV). In p a t i e n t s , XVI w a s found to be d i s t r i b u t e d i n t o t o t a l body w a t e r ; roughly 5070 of a n o r a l d o s e w a s a b s o r b e d ; and 4070 of a n i n t r a v e n o u s d o s e w a s e x c r e t e d within 6 h o u r s . 6 0 T h e d r u g i s a p o t e n t m a r r o w s u p p r e s s i v e i n a n i m a l s and m a n .
References 1. A . Goldin, A. A . S e r p i c k and N. M a n t e l , C a n c e r C h e m o t h e r a p y R e p . ,
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5 0 , 173 (1966) 2. E. J. F r e i r e i c h , E . A. G e h a n , D. P. R a l l , L. H. S c h m i d t and H. E . S k i p p e r , C a n c e r C h e m o t h e r a p y R e p . , 50, 2 19 (1966) 3. C . G. Z u b r o d , S. S c h e p a r t z , J. L e i t e r , K. M. E n d i c o t t , L. M. C a r r e s e and C . G. B a k e r , C a n c e r C h e m o t h e r a p y R e p . , 50, 349 (1966) 4. C . H e i d e l b e r g e r , Ann. R e v . P h a r m a c o l . , 7-, 101 (1967) 5. P. W . A l l a n , H. P. S c h n e b l i , and L. L. B e n n e t t , J r . , B i o c h e m . 647 (1966) Biophys. A c t a , 6. A. R . P. P a t e r s o n , M. C . Wang and A. I. S i m p s o n , P r o c . A m . A s s o c . C a n c e r R e s . , 8, 52 (1967) 7. D. G. P a r s o n s and C . H e i d e l b e r g e r , J. Med. C h e m . , 9, 159 (1966) 8. A . B l o c h , M. H. F l e y s h e r , R. T h e d f o r d , R . J. Maue and R. H. H a l l , J. Med. C h e r n . , 9 , 886 (1966) 9. R . D u s c h i n s k y , TT G a b r i e l , W . T a u t z , A. N u s s b a u m , M. H o f f e r , E . G r u n b e r g , J. H. B u r c h e n a l and J. J . F o x , J . Med. C h e m . , 2, 47 (1967) 10. J. J. V a n D y k , B. D. C l a r k s o n , R . D u s c h i n s k y , 0. K e l l e r , E. La Sala and I. H. K r a k o f f , C a n c e r R e s . , I n p r e s s 11. C . G. S m i t h , P r o c . I11 I n t . C o n g r . P h a r m a c o l . (1966) I n p r e s s 12. J. P. H o w a r d , N . C e v i k and M. L. M u r p h y , C a n c e r C h e m o t h e r a p y R e p . , 50, 287 (1966) 13. S. S i l a g i , C a n c e r R e s . , 25, 1446 (1965) 333 (1965) 14. M. Y . C h u and G. A. F i s c h e r , B i o c h e m . P h a r m a c o l . , 15. M. D o l l i n g e r , W . K r e i s , D. S t o l l , J. F o x and J. H. B u r c h e n a l , P r o c . A m . A s s o c . C a n c e r R e s . , 8, 14 (1967) 16. G. W . C a m i e n e r and C . G. S m i t h , B i o c h e m . P h a r m a c o l . , 2, 1405 (1965) 9 , 101 (1966) 17. J. J. F o x , N. M i l l e r and I. W e m p e n , J. Med. C h e m . , 1661 (1966) 18. J. H. K i m , M. L. Eidinoff and J. J. F o x , C a n c e r R e s . , W . K e r s t e n , H. K e r s t e n and W . S z y b a l s k i , B i o c h e m i s t r y , 5 , 19. - 236 (1966) 20. J. W. Y a r b r o , B. J . Kennedy a n d C . P. B a r n u m , C a n c e r R e s . , 26, 36 (1966)
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References A . C . S a r t o r e l l i and S. T s u n a m u r a , Molec. P h a r m a c o l . , g, 275 (1966) W . K r e i s , S. B. P i e p h o and H. V. B e r n h a r d , E x p e r i e n t i a , 22, 431 (1966) V . T . D e V i t a , P. P. C a r b o n e , A . H. Owens, J r . , G. L. Gold, M. J. K r a n t and J. E d m o n s o n , C a n c e r R e s . , 25, 1876 (1965) T . P. Johnston, G. S. McCaleb, P. S. O p G e r and J . A . Montgomery, J. Med. C h e m . , 9, 892 (1966) R. D. D i l l a r d , G. P o o r e , D. R. C a s s a d y , and N. R. E a s t o n , J . Med. C h e m . , 40 (1967) R . L. P. A d a m s , R . A b r a m s and I. L i e b e r m a n , J. Aiol. C h e m . , 241, 903 (1966) M. K. T u r n e r , R . A b r a m s and I. L i e b e r m a n , J. Biol. C h e m . , 241, 5777 (1966) F. S. P h i l i p s , S. S. S t e r n b e r g . H. S. S c h w a r t z , A . P. C r o n i n , J . E . S o d e r g r e n and P. M. Vidal, C a n c e r R e s . , 27, 6 1 (1967) R . Hilf, C. B e l l , I. Michel, J . J. F r e e m a n and A T B o r m a n , C a n c e r 2286 (1966) Res., G. S. T a r n o w s k i , W . K r e i s , F. A . S c h m i d , J. G. Cappuccino and J. H. B u r c h e n a l , C a n c e r R e s . , P a r t 2, 1279 (1966) G. R . G a l e , C a n c e r R e s . , 2 6 , 2340 (1966) Y . F. Shealy and C . A . O'Dyll, J. Med. C h e m . , 9, 733 (1966) T . L. Loo, E . A . S t a s s w e n d e r , J . H. J a r d i n e and E . F r e i , 111, P r o c . A m . A s s o c . C a n c e r R e s . , S, 42 (1967) C . MacDonald, N. Wollner, F. Ghavimi and J. Zweig, P r o c . A m . A s s o c . C a n c e r R e s . , S, 43 (1967)
10,
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6,
26,
S e c t i o n I V - ? l e t a b o l i c iliseases and E n d o c r i n e F u n c t i o n E d i t o r : R. V. Heinzelman, The Upjohn Company, Kalamazoo, Flichigan
C h a p t e r 1 7 . A n t i d i a b e t i c Agents Rex P i n s o n , Chas. P f i z e r & Co., I n c . , Groton, C o n n e c t i c u t T h i s r e v i e w i s e s s e n t i a l l y a c o n t i n u a t i o n of t h e same c h a p t e r i n tne 1965 Annual R e p o r t s . Its p r i m a r y p u r p o s e is t o e x t e n d and up-date t h e material presented t h e r e . Both r e v i e w s emphasize p h y s i o l o g j j and b i o c h e m i s t r y b e c a u s e t h e s i g n i f i c a n t advances i n d i a b e t e s r e s e a r c h are b e i n g made on t h e s e f r o n t s , w n i l e p r o g r e s s toward new a n t i d i a b e t i c d r u g s h a s been slow. T h i s emphasis a l s o s t e m s from a c o n v i c t i o n t h a t new a p p r o a c h e s t o a n t i d i a b e t i c t h e r a p y are most l i k e l y t o come from a p p l i c a t i o n of new knowledge a b o u t metabolism and i t s r e g u l a t i o n .
'"
The l a t t e r , by T n e r e have been two g e n e r a l r e v i e w s of d i a b e t e s . Goodner, is p a r t i c u l a r l y recoimnended f o r i t s compre!ierisive t r e a t m e n t of t h e b i o c h e m i s t r y and p h y s i o l o g y u n d e r l y i n g m e t a b o l i c r e g u l a t i o n and t h e way t h e s e p r o c e s s e s a r e deranged i n d i a b e t e s .
"Too much i s known a b o u t i n s u l i n " , complains a L a n c e t e d i t o r i a l writer,3 and s u r v e y i n g t h e mass of i n f o r m a t i o n t h a t i s y e t t o be f i t t e d i n t o a c o h e r e n t , u n i f y i n g t h e o r y of i n s u l i n s e c r e t i o n and a c t i o n , one i s i n c l i n e d t o a ree. Revievs on t h e p a n c r e a t i c B - ~ e l l ,t ~h e c h e m i s t r y and ,u ~b l i s h e d b i o c h e m i s t r y , ' b i o s y n t h e s i s ,6 s e c r e t i o n and a c t i o n of i n ~ u l i n p d u r i n g 1906, a l l l e a v e t h e i m p r e s s i o n t h a t f a r more i s known t h a n i s understood. B i o s y n t h e s i s and S t o r a g e . A v a i l a b l e e v i d e n c e l e a v e s l i t t l e doubt t h a t i n s u l i n , l i k e o t h e r p o l y p e p t i d e s , i s assembled i n l i n e a r f a s h i o n from t h e N-terminal end on a r i b o s o m a l LTA t e m p l a t e . The c h i e f q u e s t i o n h a s been w h e t n e r tne two c h a i n s are produced i n d e p e n d e n t l y o r w h e t h e r a proi n s u l i n , l i k e chymotrypsinogen, is f i r s t formed and t h e n c l e a v e d i n t o t h e two c h a i n s a f t e r t h e d i s u l f i a e l i n k a g e s have been formed. C u r r e n t e v i d e n c e f a v o r s t h e view t h a t t h e A and B c h a i n are produced i n d e p e n d e n t l y . Comb i n a t i o n o f t h e two c h a i n s a p p a r e n t l y does n o t i n v o l v e a s p e c i f i c enzyme and t h e p r o p e r a l i g n m e n t of t h e s u l f h y d r y l g r o u p s seems t o be d i r e c t e d s o l e l y by t h e c o n f i g u r a t i o n of t h e p o l y p e p t i d e c h a i n s .6 G l u t a t h i o n e i n s u l i n t r a n s h y d r o g e n a s e , which c a n c a t a l y z e t h e o x i d a t i v e c o u p l i n g of t h e two c h a i n s , a p p a r e n t l y h a s n o c a p a c i t y t o d i r e c t t h e e s t a b l i s h m e n t of a p a r t i cular configuration. The morphology of i n s u l i n s t o r a g e , as r e v e a l e d by e l e c t r o n m i c r o s c o p i c s t u d i e s , h a s been reviewed r e c e n t l y .4
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S e c r e t i o n . D e s p i t e t h e v a s t and r a p i d l y growing body of f a c t about i n s u l i n s e c r e t i o n , t h e r e is s t i l l l i t t l e i n s i g h t a t t h e m o l e c u l a r l e v e l i n t o mechanisms by which v a r i o u s s u b s t a n c e s t r i g g e r i n s u l i n r e l e a s e . It c e r t a i n l y seems t h a t t h e t i m e i s r i p e f o r u n i f i c a t i o n and c o r r e l a t i o n of t h i s knowledge and t h e f o r m u l a t i o n of hypotheses t h a t can s e r v e as a b a s i s f o r f u r t h e r experiment. The t o o l s e x i s t . Xany s u b s t a n c e s are now known t o cause t h e release of i n s u l i n from t h e p a n c r e a t i c 6 - c e l l , s e v e r a l of which appear t o do s o i n d i f f e r e n t ways. There are a l s o a nunber of i n h i b i t o r s of i n s u l i n s e c r e t i o n and t e c h n i q u e s e x i s t f o r s t u d y i n g t h e a c t i o n of t h e s e s u b s t a n c e s on p a n c r e a t i c p r e p a r a t i o n s r a n g i n g from i s o l a t e d cells t o the perfused 0 r g a n . 9 9 ~ ~ , 1 1 Recent evidence s u g g e s t s that i n s u l i n is n o t a feedback i n h i b i t o r of i t s own s e c r e t i o n . 1 2 Glucose i s one of t h e major n a t u r a l s t i m u l a n t s of i n s u l i n s e c r e t i o n . It a c t s d i r e c t l y on t h e B-cell and a p p a r e n t l y must be metabolized t o e x e r t i t s e f f e c t . Other m e t a b o l i z a b l e s u g a r s , such as f r u c t o s e a n d mannose, a l s o s t i m u l a t e i n s u l i n release b u t non-metabolizable s u g a r s do n o t .11913 I n h i b i t o r s of g l u c o s e m e t a b o l i s n such as mannoheptulose9 and 2-deoxyglucose13914 p r e v e n t g l u c o s e from s t i m u l a t i n g i r - s u l i n release. The e f f e c t of g l u c o s e i s s o r a p i d t h a t d e t e c t a b l e e l e v a t i o n s of plasma i i i s u l i n o c c u r w i t h i n one minute of s t a r t i n g a g l u c o s e i n f u s i o n . I n tile i s o l a t e d p e r f u s e a r a t p a n c r e a s , a g l u c o s e p u l s e produces a p u l s e of r e l e a s e d i n s u l i n w i t h i n 30 seconds.15 Calcium i s e s s e n t i a l t o t h e p r o c e s s and cannot be r e p l a c e d by magnesium. Potassium i s a l s o a p p a r e n t l y e s s e n t i a l and a s u f f i c i e n t l y high potassium c o n c e n t r a t i o n can cause i n s u l i r . release from i s o l a t e d pancreas preparations P r e t r e a t m e n t w i t h growth hormone o r w i t h glucoc o r t i c o i d s l e a d s t o an i n c r e a s e o r e s p o n s e of i n s u l i n s e c r e t i o n t o g l u c o s e , but n e i t h e r hormone h a s an a p p r e c i a b l e d i r e c t e f f e c t on i n v i t r o p r e p a r a tions.7rg Glucagon i s a l s o a p o t e n t , d i r e c t s t i m u l a t o r of i n s u l i n s e c r e tion10,13,17 and t h e s u g g e s t i o n has been m a d e t h a t i t s a c t i o n may be mediated through 3' ,5'-MiP, which has been found t o s t i n u 1 ; i t e i n s u l i n s e c r e t i o n d i r e c t l y . 18 Considering t h e mechanism of t h e g l y c o g e n o l y t i c e f f e c t of glucagon i n t h e l i v e r , t h i s i s a r e a s o n a b l e suggestio:i, which i s c o n s i s t e n t w i t h r e s u l t s of experiments i n man ( s e e below). The i n s u l i n r e l e a s i n g a c t i v i t y of t h e s u l f o n y l u r e a s has been s t u u i e d e x t e n s i v e l y and d i f f e r s i n i m p o r t a n t r e s p e c t s from t h a t of g l u c o s e . Mannoheptulose and d i a z o x i d e do n o t i n h i b i t t h e i n s u i i n r e l e a s i n g e f f e c t of t h e s u l f o n y l u r e a s a l t h o u g h t h e y both b l o c k g l u c o s e induced i n s u l i n secretion.9,lg The i n s u l i n r e l e a s i n g e f f e c t of amino a c i d s h a s been thoroughly reviewed.20 Plany, b u t n o t a l l , amino acids s t i m u l a t e i n s u l i n s e c r e t i o n t o some e x t e n t . A r g i n i n e , because i t i s t h e most p o t e n t , has been s t u d i e d e x t e n s i v e l y . The a c t i o n of l e u c i n e d i f f e r s s u f f i c i e n t l y from t h a t of t h e o t h e r amino a c i d s t h a t i t a p p e a r s t o f u n c t i o n by a d i f f e r e n t mechanism. A r g i n i n e is a p o t e n t s t i m u l a t o r of i n s u l i n s e c r e t i o n i n t h e normal p a n c r e a s
178
Sect. I V
- Metabolic
& Endocrine
H e i n z e l m a n , Ed.
and i t s e f f e c t i s n o t b l o c k e d by d i a z o x i d e o r by e p i n e p h r i n e . P r e t r e a t m e n t w i t h growth hormone i n c r e a s e s t h e s e n s i t i v i t y of t h e p a n c r e a s t o a r g i n i n e , as i t does t o g l u c o s e . The e f f e c t s o f l e u c i n e are somewiiat d i f f e r e n t . Althougn l e u c i n e c a u s e s s i g n i f i c a n t i n s u l i n release f roni t h e normal pancreas, e f f e c t s comparable t o t h o s c o b t a i n e d w i t h a r g i n i n e a r e a c h i e v e d 01117 on nyper-f u n c t i o n i n g p a n c r e a t i c t i s s u e - e i t h e r i n p a t i e n t s w i t h f u n c t i o n i n g i s l e t c e l l tumors o r i n s u b j e c t s s t i m u l a t e d by t h r e e days of c h l o r p r o p a m i d e p r e t r e a t m e n t . The i n s u l i n r e l e a s i n g e f f e c t s of l e u c i n e i n c n l o r p r o p a m i d e p r e t r e a t e a s u b j e c t s c a n be b l o c k e d by d i a z o x i d e . A d r e n e r g i c mechanisms a r e of g r e a t i n t e r e s t i n i n s u l i n r e l e a s e , n o t onby b e c a u s e of t h e i r p r o b a b l e i m p o r t a n c e t o t h e p n y s i o l o g i c a l c o n t r o l o f i n s u l i n s e c r e t i o n , b u t a l s o b e c a u s e t h e g e n e r a l l y n i g h l e v e l of unuer s t a n u i n g of a d r e n e r g i c mecnanisms s h o u l d l e a d , by a n a l o g y , t o a n improved u n d e r s t a n d i n g o f t h e mechanisms t h a t govern i n s u l i n release i n t h e pancreas. P r e d o m i n a n t l y u - a d r e n e r g i c s t i m u l a n t s sucli a s e p i n e p h r i n e and iiore p i n e p n r i n e i n h i b i t i n s u l i n release and t h e i r e f f e c t s c a n b e p a r t i a l l y b l o c k e d by u - a a r e n e r g i c b l o c k i n g a g e n t s such as d i h y d r c e r g c t a n i n e and The 3 - a d r e n e r g i c - s t i m u i a n t , i s o p r o t e r e n o l , on t h e o t h e r phentolamine.L1 hand, c a u s e s i n s u l i n s e c r e t i o n from t n e p a n c r e a s arid this E f f e c t c a n be a l m o s t c o m p l e t e l y b l o c k e d by t h e fi-adrenergic b l o c k i n g a g e n t , p r o p r a n o l 0 1 . ~ C~o n s i u e r i n g t h e s e e f f e c t s , and t h a t 3 ' ,5'-AYP s t i m u l a t e s i n s u l i n release d i r e c t l y , i t is n a t u r a l t o s u g g e s t t h a t t h e c y c l i c n u c l r o t i a e may be one of t h e m e d i a t o r s of i n s u l i n s e c r e t i o n . Enhancement of i n s u l i n s e c r e t i o n by t h e o p h y l l i n e , a p n o s p h o a i e s terase i n h i b i t o r , s u p p o r t s t h i s i d e a . 1 9 :.loreover, p r o p r a n o l o l , w:iich i s known t o i n i i i b i t i s o p r o t e r e n o l but n o t g l u c a g o n a c t i v a t i o n of a d e n y l c y c l a s e , ' o l o c ~ si s o p r o t e r e n o l hyperg l y c e n i a and i n s u l i n release, b u t does n o t i n h i b i t e i t h e r t h e h y p c r g l y c e n i a o r i n s u l i n release c a u s e d by glucagon i n tiuman s u b j c c t s . 2 2 The h y p e r g l y c e m i c e f f c c t s of d i a z o x i d e a r e w e l l documented and a r e known t o r e s d t from dn i n h i b i t i o n of g l u c o s e u p t a k e i n periixieral t i s s u e as w e l l as i n h i b i t i o n of i n s u l i n release from t n e paixreas.19 u i a z o x i a e h a s no e f f e c t on i n s u l i n release by t h e s u l f o n y l u r e a s o r a r g i n i n e , 2 0 b u t b l o c k s g l u c o s e and leucine2' s t i m u l a t i o n of i n s u l i n s e c r e t i o n . Diazoxitie i n h i b i t i o n o f i n s u l i n s e c r e t i o n can be a t l e a s t p a r t i a l l y r e v e r s e d by aa d r e n e r g i c b l o c k i n g a g e n t s .19 ! f i a t e v e r t h e p r i m a r y a c t i o n of d i a z o x i d e , i t i s a s s a r e n t l y s u f f i c i e n t t o overcome i t s p h o s p h o d i e s t e r a s e i n h i b i t o r y action, wiiich would b e e x p e c t e d t o p o t e n t i a t e i n s u l i n s e c r e t i o n , as t h e o p h y l l i n e does. C o n s i d e r i n v t h e known e f f e c t s of d i a z o x i d e on i n t r a c e l l u l a r e l e c t r o l y t e b a l a n c e , 2 9 i t would be i n t e r e s t i n g t o examine t h i s a s p e c t of i t s a c t i o n i n c o n n e c t i o n w i t h e f f e c t s on i n s u l i n release. That p o t a s s i u m i s e s s e n t i a l f o r i n s u l i n s e c r e t i o n and c a n e v e n s t i m u l a t e t h e p r o c e s s , h a s been x e n t i o n e d . Convincing e v i d e n c e h a s been o f f e r e d t h a t c a r b o h y d r a t e i n t o l e r a n c e t h a t inay w e l l d e r i v e from i n s u f f i c i e n t i n s u l i n s e c r e t i o n is f r e q u e n t l y a s s o c i a t e d w i t h c l i n i c a l s t a t e s of p o t a s s i u m d e f i c i e n c y , e s p e c i a l l y primary a l d o s t e r o n i s m . 24 h comprehcnsive l i s t i n g of t h e a c t i o n s of i n s u l i n is I n s u l i n Act-. g i v e n by W i l l i a m s and Lnsincl: i n t h e i r re vie^.^ The s p e c i f i c e f f e c t s of i n s u l i n on plasma c a r b o h y d r a t e atid l i p i d t u r n o v e r have a l s o been re-
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viewed.25 S t e i n e r h a s reviewed t h e e f f e c t s of i n s u l i n on metabolism i n t h e l i v e r and h a s i n c l u d e d a t h o u g h t f u l a n a l y s i s , i n s o f a r as one i s now p o s s i b l e , of t h e r e l a t i v e e f f e c t s of s u b s t r a t e a v a i l a b i l i t y , enzyme synt h e s i s and a l l o s t e r i c e f f e c t s . 2 G Weber and h i s c o l l e a g u e s Iiave reviewed the concept t h a t i n s u l i n functions over the r e l a t i v e l y long t e r m t o control t h e m e t a b o l i c a c t i v i t y of t h e l i v e r by a c t i n g as a n i n d u c e r o f g l y c o l y t i c enzyines and a r e p r e s s o r o f g l u c o n e o g e n i c enzymes.27 O t h e r r e v i e w s on t h e c o n t r o l o f l i v e r metabolism emphasize t h e s h o r t e r t e r m f e e d b a c k c o n t r o l Some new d a t a on t h e e f f e c t s e x e r t e d by m e t a b o l i c o f a c u t e and c h r o n i c i n s u l i n d e p r i v a t i o n on h e p a t i c metabolisro a r e a l s o v a l u a b l e . 32 9 33 L e v i n e c u r r e n t l y views t h e a c t i o n of i n s u l i n a s o c c u r r i n g p r i m a r i l y a t t h e c e l l membrane, b u t c e r t a i n l y n o t as a p r i m a r y e f f e c t s o l e l y on g l u c o s e t r a n s p o r t , from which a l l o t h e r e f f e c t s d e r i ~ e . 3 ~H e makes t h e i m p o r t a n t p o i n t t h a t i n t r a c e l l u l a r e f f e c t s do n o t n e c e s s a r i l y mean i n t r a c e l l u l a r p r e s e n c e . I n d e e d few, i f a n y , o f t h e p o s t u l a t e d a c t i o n s o f i n s u l i n have b e e n produced i n c e l l f r e e s y s t e m s and t h e r e remains no conv i n c i n g e v i d e n c e t h a t i n s u l i n p e n e t r a t e s beyond t h e c e l l membrane. Although t h e r e is now good e v i d e n c e t h a t i n s u l i n c a n s t i m u l a t e p r o t e i n s y n t h e s i s i n d e p e n d e n t l y of amino a c i d t r a n s p o r t f a c i l i t a t i o n , i t h a s n o t been p o s s i b l e t o d e m o n s t r a t e a d i r e c t e f f e c t of i n s u l i n on a complete c e l l f r e e p r o t e i n s y n t h e s i z i n g s y s t e m i n v i t ~ o . ~ The ~ , e~f f e~ c t of i n s u l i n t r e a t m e n t o r i n s u l i n d e p r i v a t i o n on t h e a n i m a l ( o r i s o l a t e d p e r f u s e d l i v e r ) Potassium from which t h e p r e p a r a t i o n i s made, are r e a d i l y s e e n , however. b a l a n c e i n muscle h a s proved t o be remarkably s e n s i t i v e t o i n s u l i n . I n muscle p r e p a r a t i o n s , i o n f l u x e s c a n be s e e n a f t e r t r e a t m e n t w i t h i n s u l i n a t l e v e l s t h a t p r o d u c e no d e t e c t a b l e e f f e c t on g l u c o s e metabolism.37 I n s u l i n r a p i d l y r e d u c e s 3' ,5 '-AXP l e v e l s i n a d i p o s e t i s s u e , p r o b a b l y by i n h i b i t i n g a d e n y l c y c l a s e , and t h i s e f f e c t h a s been s u g g e s t e d as t h e b a s i s of t h e d i r e c t , a n t i l i p o l y t i c a c t i o n of i n s u l i n . 3 8 A p r o v o c a t i v e r e c e n t paper presents evidence suggesting t h a t during i n s u l i n a c t i v a t e d glucose t r a n s p o r t a c r o s s t h e r a t f a t c e l l membrane, t h e s u g a r s form e i t h e r irnines o r g l y c o s y l a m i n e s w i t h t h e €-amino group of l y s i n e residue..39
Two new t h e o r i e s of i n s u l i n a c t i o n have been o f f e r e d and comnented o n . 3 Bessnan h a s s u g g e s t e d t h a t i n s u l i n a c t s by forming a m e c h a n i c a l l i n k between h e x o k i n a s e and t h e m i t o c h o n d r i o n , t h u s p r o n o t i n g e f f i c i e n c y by Uornandy a n c h o r i n g a n ATP r e q u i r i n g p r o c e s s n e a r i t s s o u r c e of s u p p l y . 4 o h a s s u g g e s t e d , from e x p e r i m e n t s u s i n g e r y t h r o c y t e s and hemoglobin, t h a t i n s u l i n h a s a n immediate p h y s i c a l a c t i o n on t h e c e l l - e x t r a c e l l u l a r i n t e r f a c e , a l t e r i n g t h e redox p o t e n t i a l g r a d i e n t a c r o s s t h e plasma P l a s m a F a c t o r s t h a t I n f l u e n c e I n s u l i n Acti'on. d e r s o n and Yalow a r g u e p e r s u a s i v e l y t h a t t h e r e i s n o e v i d e n c e t h a t i n s u l i n of p a n c r e a t i c o r i g i n e v e r becomes bound t o a plasma p r o t e i n , from which i t c a n s u b s e q u e n t l y be N e w e r e v i d e n c e , b a s e d on a n examinatioii r e l e a s e d i n r e c o g n i z a b l e i0rin.42 of t h e i n s u l i n - l i k e a c t i v i t y of plasina, from wiiich a l l i n n u n o r e a c t i v e i n s u l i n had been p r e c i p i t a t e d w i t h a n t i - i n s u l i n serum, c o c f i r m s t h i s conc l u s i 0 n . ~ 3 N e v e r t h e l e s s , t h e r e i s ample e v i d e n c e t h a t t h e r e e x i s t ii; plasma, s u b s t a n c e s t h a t have i n s u l i n - l i k e a c t i v i t y o r t h a t c a n modify t h e c _
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a c t i o n of i n s u l i n i n e x p e r i r n c n t a l s y s t e m s . ‘Tnerc now seems t o be g e n e r a l a c c e p t a n c e of t h e view t h a t bound i n s u l i n ( A n t o c i a d e s ) , a t y p i c a l i n s u l i n (Samaan and F r a s e r ) , and n o n s u p r e s s a b l e i n s u l i n ( F r o e s c h ) are t h e same. I n d e e d , t h e r e i s as y e t no c o n v i n c i n g e v i d e n c e t o r u l e o u t t h e p o s s i b i l i t y t h a t s u c h i n s u l i n - l i k e a c t i v i t y i s a l s o i d e n t i c a l t o t h e Vallance--Owen i n s u l i n a n t a g o n i s t . 44 The two classes of s u b s t a n c e s have g e n e r a l l y been r e g a r d e d as d i f f e r e n t b e c a u s e t h e y are p r e p a r e d i n d i f f e r e n t ways and t h e r e h a s been a tendency t o e x p l a i n c e r t a i n s i m i l a r i t i e s i n t h e i r a c t i o n by A l i n e of e x p e r i m e n t a t i o n t h a t a d o p t e d p o s t u l a t i n g cross-contamination.45 t h e view t h a t t h e two s u b s t a n c e s were t h e same and t h e n a t t e m p t e d t o u p s e t t h i s h y p o t h e s i s , might y i e l d some v e r y i n t e r e s t i n g r e s u l t s . Bo+h m a t e r i a l s i n h i b i t i n s u l i n u p t a k e by i s o l a t e d muscle and a d i p o s e t i s s u e , i n h i b i t t h c a c t i o n o f i n s u l i n on muscle (diaphragm) and show insulin-1ik-e a c t i v i t y on adipose tissue.45 I n v i v o a c t i v i t i e s of b o t h p r e p a r a t i o n s have been d e m o n s t r a t e d by i n j e c t i o n o f t h e p a r t i a l l y p u r i f i e d f a c t o r s i n t o rats .46,47,48 Some of t h e s e , employing i n t r a p e r i t o n e a l i n j e c t i o n s and e x a m i n a t i o n f o r e f f e c t s on t h e diaphragm, a p p e a r t o be s p e c i a l cases o f i n v i t r o e x p e r i m e n t s , however, s i n c e t h e diaphragm w a s s u r e l y d i r e c t l y exposed t o a p p r e c i a b l e c o n c e n t r a t i o n s of t h e i n j e c t e d m a t e r i a l . 48 The e x i s t e n c e o f b o t h a n albumin i n s u l i n a n t a g o n i s t and bound i n s u l i n h a s been d e m o n s t r a t e d i n rat plasma. 49 The l e v e l o f plasma n o n s u p r e s s a b l e i n s u l i n h a s been found n o t t o d e c r e a s e d u r i n g s u p r e s s i o n of i n s u l i n s e c r e t i o n by mannoheptulose.50 A d d i t i o n a l e v i d e n c e h a s been o b t a i n e d t h a t t h e s u l f o n y l u r e a s do n o t release i n s u l i n from bound i n s u l i n p r e p a r a t i o n s .51
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S e v e r a l g r o u p s a r e s t u d y i n g t h e Vallance-Gwen i n s u l i n a n t a g o n i s t from v a r i o u s p o i n t s o f view. P u r i f i c a t i o n l e a d i n g t o 150 f o l d e n r i c h m e n t h a s been c a r r i e d o u t . 5 2 R e p r o d u c i b i l i t y of p r e p a r a t i o n s of t h e a n t a g o n i s t from plasma h a s o f t e n been poor53354 and t h e u s e of a l t e r n a t e albumin i s o l a t i o n methods h a s l e d t o f r a c t i o n s w i t h i n s u l i n - l i k e a c t i v i t y b u t n o i n h i b i t o r y a ~ t i v i t y . 5 ~F u r t h e r c o n f i r m a t i o n h a s been o b t a i n e d t h a t t h e albumin f r a c t i o n from d i a b e t i c plasma c o n t a i n s c o n s i s t e n t l y more i n h i b i t o r y a c t i v i t y t h a n t h a t from n o n d i a b e t i c s u b j e c t s .53 P r c p n r a t i o n s o b t a i n e d t o d a t e are s t i l l f a r from homogeneous and have been shown t o c o n t a i n ag l o b u l i n s . 5 3 From t h e i r s t u d i e s on t h e mechanism of a c t i o n of t h e Vallence-Owen i n s u l i n a n t a g o n i s t , Davidson and Goodner c o n c l u d e t h a t i t s p r i m a r y e f f e c t i s t o b l o c k t h e s u g a r t r a n s p o r t e f f e c t of i n u l i n and t h a t albumin bound f r e e f a t t y a c i d s p l a y no p a r t i n i t s a c t i o n . 5 3 There i s still no c o n c l u s i v e e v i d e n c e t o i n d i c a t e w h e t h e r t h e Vallance--Owen i n s u l i n a n t a g o n i s t , a s had been p o s t u l a t e d e a r l i e r , i s t h e albumin complex of t h e i n s u l i n B-chain, b u t p r e p a r e d m i x t u r e of reduced 1) c h a i n and albumin d i d i n c r e a s e h y p e r g l y c e m i a i n r a t s made d i a b e t i c by a h i g h p r o t e i n , high f a t d i e t . 5 6 The s e p a r a t e A and I3 c h a i n s b o t h i n h i b i t e d g l u c o s e u p t a k e i n diaphragm, b u t n e i t h e r b l o c k e d t h e s t i r n u l a t o r y e f f e c t of added i n s u l i n . The A c h a i n , b u t n o t t h e B c h a i n , i n c r e a s e d t h e i n c o r p o r a t i o n of g l u c o s e c a r b o n i n t o CO i n a d i p o s e t i s s u e . T h i s a c t i o n c o u l d be b l o c k e d by a n t i i n s u l i n serum. 3 7 Evidence h a s been o f f e r e d f o r t h e e x i s t e n c e of a hormone, produced i n - t h e l i v e r and u n d e r p i t u i t a r y c o n t r o l , t h a t f a v o r s l i p o g e n e s i s from A substance t h a t g l u c o s e by i n h i b i t i n g t h e a c t i o n of i n s u l i n on muscle.58
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s t i m u l a t e s t h e u p t a k e of n o n u t i l i z a b l e s u g a r s by t h e r a t diaphragm, r e m i n i s c e n t of t h e G o l d s t e i n work f a c t o r , h a s been i s o l a t e d from t h e g a s p e r f u s e d c a t iieart .59 O t h e r Hormones The p i t u i t a r y growth hormone i s known t o e x e r t profound e f f e c t s on metabolism and p a n c r e a t i c f u n c t i o n . Although t h e hormone has l i t t l e e f f e c t on a c u t e a d m i n i s t r a t i o n o r on t i s s u e s i n v i t r o , c o n t i n u e d administ r a t i o n l e a d s t o s u b s t a n t i a l l y e l e v a t e d plasma i n s u l i n l e v e l s and i n c r e a s e u i n s u l i n s e c r e t i o n i n r e s p o n s e t o a g l u c o s e load.60 A t h e o r y t h a t t h e anab o l i c e f f e c t s of growth hormone r e q u i r e t h e a d d i t i o n a l e f f e c t of i n s u l i n and t h a t , w i t h r e l a t i v e d e f i c i e n c y o f i n s u l i n , i t s d i a b e t o g e n i c a c t i o n ( e l e v a t e d f r e e f a t t y a c i d l e v e l s and d e c r e a s e d g l u c o s e p e n e t r a t i o n ) p r e dominates has been p r o p o s e d . 6 1 The r o l e of growth hormone as a p a t h o g e n i c a g e n t i n d i a b e t e s h a s been q u e s t i o n e d r e c e n t l y , p a r t l y as a r e s u l t of s t u d i e s on p a t i e n t s who underwent p i t u i t a r y s t a l k s e c t i o n t o r e l i e v e r e t i n o p a t h y . T h i s i s t a k e n as f u r t h e r c o n f i r m a t i o n t h a t w h e t h e r growth hormone is d i a b e t o p e n i c p r o b a b l y depends on w h e t h e r t h e r e i s an a d e q u a t e s u p p l y of i n s u l i n . 62 Glucagon and e p i n e p h r i n e a c u t e l y s t i m u l a t e g l u c o n e o g e n e s i s i n p e r The hormone s e n s i t i v e s t e p f u s e d r a t l i v e r , p r o b a b l y t h r o u g h 3,'5'-XiP. i s a p p a r e n t l y b e f o r e t h e f o r m a t i o n of t h r e e c a r b o n i n t e r m e d i a t e s , s i n c e g l u c o n e o g e n e s i s from f r u c t o s e i s u n a f f e c t e d . 6 3 The e f f e c t of c a t e c h o l amines and o t h e r hormones on l i p i d m o b i l i z a t i o n h a s been w e 1 1 reviewed by S t e i n b e r g . 6 4 I n t e r n e d i a r y :,!etabolism One of t n e most i m p o r t a n t p r o d u c t s of r e s e a r c h on d i a b e t e s has been i n c r e a s e d u n d e r s t a n d i n g of t h e p:iysiology and b i o c h e m i s t r y of m e t a b o l i c I t is o b v i o u s l y i m p o s s i b l e , i n a review of t h i s k i n d , t o regulation. c i t e more t h a n a few o f t h e advances t h a t have been made, even i n a s i n g l e y e a r . T h e s e l e c t i o n here i s based on a juugment of t h e i r s i g n i f i c a n c e t o d i a b e t e s , h e a v i l y w e i g h t e d by t h e p e r s o n a l i n t e r e s t of t h e reviewer. S e v e r a l nave a l r e a d y been mentioned i n c o n n c c t i o n v i t h hormoiie xtivities. i:aridle h a s reviewed :)is c o n c e p t of a g l u c o s e - f a t t y a c i d c y c l e , w i t h some new e x p e r i m e n t a l material.'' T h e r e ilas been a r e c e n t review of g l u c o n e o g e n e s i s , w i t h good c u r r e n t r e f e r e n c e s . 6 6 ?lie c o n t r o l of p,iospiiof z u c t o k i n a s e , one of t h e i m p o r t a n t r a t e l i m i t i n g enzymes of g l y c o l y s i s , i s s t i l l n o t f u l l y u n d e r s t o o d . Thc a c t i v i t y of tr,e enzyme i n m a m n i a l i m n:uscle i s i n f l u e n c e d by s u b s t r a t e c o n c e n t r a t i o n and by 3 ' ,5'-fL'!P, wiiich c a n a c t i v a t e t h e ATP i n h i b i t e d enzyme, a g p a r e n t l y by a n a l l o s t e r i c e f f e c t . Activ a t i o n by e p i n e p h r i n e :)as n o t been d e m o n s t r a t e d , however, an6 o t h e r a d e n i n e n u c l e o t i d e s may u e l l be i n v o l v c u . ( ~ 7 G l u c o k i n a s e , p r e v i o u s l y found i n r a t l i v e r , h a s now 5ecn i d e n t i f i e u i n e x t r a c t s of l i v e r fro-r. well n o u r i s h e a Fatty tiumans and dogs, b u t i s a b s e n t d u r i n g p e r i o d s of poor n u t r i t i o n . 6 6 a c i d s h a v e been found t o i n h i b i t s e v e r a i l i v e r g l y c o l y t i c enzymes and
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e s p e c i a l l y p y r u v a t e k i n a s e . A scheme whereby t h i s e f f e c t c o u l d a c t t o change t h e m e t a b o l i c a c t i v i t y of t h e l i v e r from g l y c o l y s i s t o gluconeog e n e s i s h a s been proposed. G 9 The r e g u l a t i o n of f a t t y a c i d s y n t h e s i s i n a d i p o s e t i s s u e h a s been reviewed by Ball, w i t h emphasis on a citrate-malate c y c l e t h a t p r o v i d e s b o t h e x t r a m i t o c h o n d r i a l acetyl-CoA and p a r t of t h e NAUPH r e q u i r e e f o r f a t t y a c i d s y n t h e s i s . 70 F u r t h e r q u a n t i t a t i v e work on t h e pathways of g l u c o s e and a c e t a t e c a r b o n i n a d i p o s e t i s s u e h a s a l s o been r e p o r t e d . 7 1 S u l f o n y l u r e a s and t h e i r Congeners The i n t r o d u c t i o n t o t h e r a p y o f t o l a ~ a r n i d eb~r i~n g s t o f o u r t h e number of s u l f o n y l u r e a s o r r e l a t e d compounds commercially a v a i l a b l e i n t h e U n i t e d S t a t e s . A comprehensive i n v e s t i g a t i o n of t h e metabolism and exc r e t i o n of a c e t o h e x a m i d e i n human s u b j e c t s h a s l a r g e l y confirmed t h e conc l u s i o n s r e a c h e d i n e a rlie r s t u d i e s and t h e r e p o r t of t h i s work i n c l u d e s l e a d i n g r e f e r e n c e s t o s t u d i e s on t h e metabolism of o t h e r s u l f o n y l u r e a s .73 1-Butyl-3- (p-hydroxymethyl) b e n z e n e s u l f o n y l u r e a h a s been i d e n t i f i e d as a s i g n i f i c a n t m e t a b o l i t e o f t o l b u t a m i d e i n man and t h e predominant m e t a b o l i t e i n t h e rat.87 I n a p i l o t c l i n i c a l e v a l u a t i o n , l-cyclohexyl-3(4-trifluoromethyl-benzenesulfony1)urea gave s a t i s f a c t o r y d i a b e t i c c o n t r o l w i t h dosage o n c e a day.74 An i n v e s t i g a t i o n o f t h e hypoglycemic a c t i v i t and t c x i c i t y of a hypoglycemic s u l f a t h i a d i a z o l e ( I ) h a s been p u b l i s h e d . 7 3 A series o f e x c e p t i o n a l l y p o t e n t s u l f o n y l u r e a s h a s been r e p o r t e d . T h r e s h o l d hypoglycemic d o s e s o f t h e most a c t i v e compound (11) i n t h e r a t and dog w e r e o n l y 0 .OO5-O.O2O t h a t of t o l b u t a m i d e . Mypoglycemic a c t i v i t y a t 0 . 1 mg/kg i n humans w a s r e p 0 r t e d . 7 ~ A number of p i p e r a z i n e s u l f a m y l c o n g e n e r s of a n e a r l i e r s e r i e s of s u l f a m y l u r e a s have been s y n t h e s i z e d .
8""
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F u r t h e r s t u d i e s have confirmed t h a t p r o l o n g e d s u l f o n y l u r e a t r e a t m e n t does n o t l e a d t o e x h a u s t i o n of tile p a n c r e a s , b u t s l i g h t l y i n c r e a s e s i t s i n s u l i n s e c r e t i n g capacity. 77 Biguanides When w r i t i n g a b o u t phenformin and t h e o t n e r b i g u a n i d e s , a u t h o r s a l m o s t w i t h o u t e x c e p t i o n s t a t e t h a t t h e mechanism of t h e hypoglycemic
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a c t i o n of t h e s e d r u g s i s unknown. The w e i g h t o f e v i d e n c e now a v a i l a b l e l e a d s one t o q u e s t i o n s e r i o u s l y whether t h i s d i s c l a i m e r is s t i l l w a r r a n t e d
I t now seems r e a s o n a b l e t o a c c e p t , as was proposed some y e a r s ago, t h a t t h e p r i m a r y a c t i o n of phenformin i s t o i n h i b i t e n e r g y t r a n s f e r a t * ~ (t Jh a t t h i s t h e cytochrome b s i t e of t h e energy t r a n s p o r t c i ~ a i n ~ ~ arid r e s u l t s i n d e c r e a s e d ATP c o n c e n t r a t i o n s and i n c r e a s e d i n o r g a n i c phosp h a t e and AXP c o n c e n t r a t i o n s . The known e f f e c t s o f phenformin on metab o l i s m c a n r a t i o n a l l y be t r a c e d back t o t h i s p r i m a r y e f f e c t on e l e c t r o n t r a n s p o r t . The most i m p o r t a n t of t h e s e e f f e c t s on m e t a b o l i s m a r e i n c r e a s e d g l y c o l y s i s i n a d i p o s e t i s s u e and muscle and reduced gluconeogenesis i n the l i v e r . Both c a n be a c c o u n t e d f o r by t h e r e s u l t i n g r e d u c t i o n i n t h e ATP/AMP r a t i o , which r e g u l a t e s t h e a c t i v i t y o f t h e key enzymes o f g l y c o l y s i s , g l u c o n e o g e n e s i s and o x i d a t i v e m e t a b o l i s m i n ways t h a t are now r e a s o n a b l y w e l l u n d e r s t o o d . Whether hypoglycemia r e s u l t s i n a g i v e n c i r c u m s t a n c e w i l l depend on t h e b a l a n c e of t h e e f f e c t s on glycol y s i s and g l u c o n e o g e n e s i s - - t h a t i s , how r a p i d l y t h e l a c t a t e formed by g l y c o l y s i s i n f a t and muscle is r e c o n v e r t e d t o g l u c o s e i n t h e l i v e r . The o p e r a t i o n o f t h i s b a l a n c e of e f f e c t s has been e l e g a n t l y d e m o n s t r a t e d by A l t s c h u l d and Kruger." I n b o t h i n v i v o and i n v i t r o e x p e r i m e n t s , t h e y showed t h a t t h e g u i n e a p i g , which is q u i t e s e n s i t i v e t o t h e hypoglycemic e f f e c t s of D B I , r e s p o n d s t o t h e d r u g w i t h d e c r e a s e d l i v e r ATP l e v e l s and marked r e d u c t i o n i n g l u c o n e o g e n e s i s from l a c t a t e and g l y c e r o l . The r a t , on t h e o t h e r hand, which is q u i t e i n s e n s i t i v e t o t h e hypoglycemic e f f e c t s o f DBI showed no s i g n i f i c a n t r e d u c t i o n of e i t h e r ATP levels o r gluconeog e n e s i s . I n r e c e n t s t u d i e s , which h e r e g a r d s as p r e l i m i n a r y b e c a u s e of t h e s m a l l number o f p a t i e n t s i n v o l v e d , K r e i s b e r g found t h a t phenformin i n h i b i t e d g l u c o n e o g e n e s i s ( o b s e r v a b l e as a r e d u c t i o n i n t h e a b s o l u t e q u a n t i t y o f g l u c o s e r e c y c l e d and a r e d u c t i o n i n g l u c o s e r e p l a c e m e n t r a t e ) .81 S e v e r a l o b j e c t i o n s t o t h i s mechanism f o r t h e hypoglycemic a c t i o n of Some a d d i t i o n a l t h e b i g u a n i d e s were d i s c u s s e d i n l a s t y e a r ' s review. comment on t h e s e i s a p p r o p r i a t e h e r e . The e v i d e n c e t h a t t h e hypoglycemic a c t i o n of t h e b i g u a n i d e s depends u l t i m a t e l y on a n i n h i b i t i o n of o x i d a t i v e p r o c e s s e s rests h e a v i l y on t h e r e s u l t s o f i n v i t r o e x p e r i m e n t s . I t h a s f r e q u e n t l y been o b j e c t e d t h a t t h e c o n c e n t r a t i o n of t h e b i g u a n i d e s n e c e s s a r y t o p r o d u c e t h e o b s e r v e d e f f e c t is s u b s t a n t i a l l y g r e a t e r t h a n i s o b t a i n e d i n vivo. I n one r e c e n t s t u d y , however, u s i n g i s o l a t e d t i s s u e s from t h e g u i n e a p i g , t h e r a t and t h e p i g e o n , t h e d r u g c o n c e n t r a t i o n r e q u i r e d t o i n h i b i t o x i d a t i v e p r o c e s s e s was e s s e n t i a l l y t h e sane as t h a t r e q u i r e d t o s t i m u l a t e g l u c o s e u p t a k e and t h e c o n c e n t r a t i o n s w e r e i n t h e r a n g e t h a t d r u g m e t a b o l i s m s t u d i e s s u g g e s t a r e a t t a i n e d An vivo.82 Moreover, t h e r e l a t i v e s e n s i t i v i t y of t h e t i s s u e s was. i n t h e sane o r d e r as t h e r e l a t i v e s e n s i t i v i t y of the t h r e e s p e c i e s t o t h e iiy;ioblycenic a c t i o n of t h e b i g u a n i d e s . I n a n o t h e r i n v e s t i g a t i o n , a number o f t h e e f f e c t s of phenformin on m e t a b o l i s m i n r a t a d i p o s e t i s s u e , - - i n h i b i t i o n of g l u c o s e o x i d a t i o n and l i p o g e n e s i s , b o t h b a s a l and i n s u l i n s t i m u l a t e d - were t r a c e d t o a n i n h i b i t i o n of p y r u v a t e o x i d a t i o n , presumably r e s u l t i n g from i n t e r f e r e n c e w i t h e l e c t r o n t r a n s p o r t . 8 3
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& Endocrine
H e i n z e l m a n , Ed.
T h e s u g g e s t i o n t h a t t h e b i g u a n i d e s p o t e n t i a t e t h e a c t i o n of: i n s d i n by i n c r e a s i n g t h e u p t a k e of i n s u l i n by muscleb4 SCCI;.S q u e s t i o n a b l e . I f t h i s were t h e case, one would e x p e c t t h e e f f e c t s of t h e b i g u a n i d e s on metabolism t o p a r a l l e l t h o s e o f i n s u l i n , b u t i n f a c t , tiicy are u s u a l l y t h e o 2 p o s i t e . I n s u l i n proiaotes glycogen d e p o s i t i o n , 1 i T o e n e s i s . and p r o t e i n s y n t h e s i s , a l l of which t h e b i g u a n i d e s o p p o ~ e . ~ ~ ~ ~ ~ Convincing c i i n i c a l r e p o r t s t h a t phenforiair. treatmezt r e s u l t s i n w e i g h t l o s s c o n t i n u e t o a p p e a r , 8 6 ’ 6 7 b u t no b i o c h e n i c a l l y r a t i o n a l e x p l a n a t i o n f o r t h i s e f f e c t h a s y e t been advanced. I n h i b i t i o n of l i p o g e n e s i s h a s f r e q u e n t l y been mentioned as t h e c a u s e of t h e o b s e r v e d w e i g h t l o s s , and is o f t e n a t t r i b u t e d t o d e c r e a s e d plasma i n s u l i n l e v e l s . Cert a i n l y t h i s is a well d o c u a e n t e d m e t a b o l i c a c t i o n of t n e b i g u a n i d e s , b u t i t is c l e a r l y i n s u f f i c i e n t t o e x p l a i n weight l o s s . !.;:?ether d i e t a r y c a r b o h y d r a t e is more o r less r e a d i l y c o n v e r t e d t o f a t c a n have no e f f e c t on body w e i g h t u n l e s s t h e r e i s a n e t l o s s of c a r b o n frolii t h e system. Whca w e i g h t l o s s is due t o a n i m b a l a n c e between c a l o r i c i n t a k e and energy Phenformin e x p e n d i t u r e , t h e n e t l o s s o f c a r b o n i s i n tile form of C 0 2 . h a s been r e p o r t e d t o c a u s e a n i n c r e a s e i n n e t c o n v e r s i o n of g l u c o s e c a r b o n b u t a n a t t e m p t t o confirm t h e o b s e r v a t i o n has t h u s f a r failed.81 t o CO 2’ Both i n v e s t i g a t i o n s , however, are i n r e l a t i v e l y e a r l y s t a g e s and r c s o l u t i o n of t h e q u e s t i o n must a w a i t t h e r e s u l t s of f u r t h e r work. T i i e r e c o u l d be a n e t l o s s of c a r b o n i n b i g u a n i d e t r e a t e d p a t i e n t s t h r o u g h u r i n a r y e x c r e t i o n of l a c t a t e , b u t t h e r e i s l i t t l e e v i d e n c e t o s u g g e s t t h a t t h i s o c c u r s t o a s i g n i E i c a n t e x t e n t . Weight l o s s due t o b i g u a n i d e t r e a t m e n t iias been a t t r i b u t e d by some i n v e s t i g a t o r s t o t h e a n o r e c t i c e f f e c t of t h e d r u g , and c o n s i d e r i n g t h e d i f f e r e n c e s t n a t s m a l l decrements of c a l o r i c i n t a k e c a n make, i t is n o t p o s s i b l e t o d i s m i s s t h i s s u g g e s t i o n from d a t a p r e s e n t l y a v a i l a b l e , e s p e c i a l l y without an a l t e r n a t e r a t i o n a l i z a t i o n .
‘’
O t h e r Hypoglycemic Conpounds
A series o f 4-(l-naphthyl)butylamines, f o r t h e most p a r t d e r i v a t i v e s o f n a p h t h y l a c e t i c a c i d , have shown hypoglycemic a c t i v i t y comparable, i n t h e most a c t i v e members, t o c h l ~ r p r o p a m i d e . ~A ~s u p e r f i c i a l s t r u c t u r e a c t i v i t y a n a l y s i s h a s been a t t e m p t e d , b u t no d e t a i l s of t h e i r a c t i o n have been p u b l i s h e d . go Acknowledgement. I am much indebted to my colleagues B.M. Bloom, F. A. Hochstein, and N. 0. Jangaard f o r their stimulating suggestions. I am also indebted to I.I.A. Tabachnlck, R. A. Altschuld, F. A. Kruger, R. A. Kreisberg and S. S. Fajans f o r allowing me to use publications still in press. References 1.
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Is,
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Chapter 18. A t h e r o s c l e r o s i s Joseph J . Ursprung, The Upjohn Company, Kalamazoo, Michigan Introduction - The importance of a t h e r o s c l e r o s i s as a cause of death and d i s a b i l i t y , e s p e c i a l l y i n Europe and North America has i n c r e a s e d t r e mendously w i t h i n t h e p a s t few decades. This i s p a r t l y bec:ause, w i t h t h e advancement of medical science, more people l i v e l o n g e r . Neverthel e s s , t h e development of a t h e r o s c l e r o s i s severe enough t o jeopardize normal function, o r even l i f e i t s e l f , cannot b e considered a normal p a r t of t h e aging process. Many f a c t o r s have been implicated i n i t s g e n e s i s : d i e t , h e r e d i t y , s t r e s s , o b e s i t y , hypertension, metabolic d i s o r d e r s such as d i a b e t e s and hypothyroidism, c l i m a t e and smoking. Probably no one f a c t o r alone produces t h e degenerative changes seen i n advanced atheros c l e r o t i c d i s e a s e . There i s c i r c u m s t a n t i a l evidence t h a t manipulation of one or s e v e r a l of t h e s e b a s i c f a c t o r s w i l l b e n e f i t a t least some percentage of t h e population and t h e r e f o r e t h e s e must be pursued. Preventive treatment d i r e c t e d s o l e l y a g a i n s t b a s i c causes may be i m p r a c t i c a l and perhaps a more l o g i c a l approach i s t o t r y t o prevent o r i n h i b i t formation of atheromatous plaques which e v e n t u a l l y become c a l c i f i e d , r e s u l t i n g i n t h e c h a r a c t e r i s t i c l e s i o n of a r t e r i o s c l e r o s i s . The Framingham study continues t o y i e l d information c o r r e l a t i n g serum l i p i d l e v e l s w i t h coronary h e a r t d i s e a s e . Risk of coronary d i s e a s e i s r e l a t e d t o l i p o p r o t e i n s and t h e i r l i p i d s . ’ This r i s k could be p r e d i c t e d a t a l l ages f o r men, b u t only b e f o r e t h e age o f 50 f o r women. I n d i a b e t i c s excess of h e a r t d i s e a s e occurs r e l a t e d t o e l e v a t i o n of l i p o p r o t e i n l e v e l s , e s p e c i a l l y t r i g l y c e r i d e - r i c h p a r t i c l e s . T r i g l y c e r i d e and c h o l e s t e r o l c o n c e n t r a t i o n s and l e v e l s of t h e i r t r a n s p o r t i n g v e h i c l e s independently e x e r t an i n f l u e n c e on h e a r t d i s e a s e . The same study showed t h a t r i s k of angina p e c t o r i s and sudden death w a s proport i o n a l t o t h e degree of overweight.2 Adiposity, however, proved u n r e l a t e d t o t h e r a t e of development of myocardial i n f a r c t i o n . The c o n t r i b u t i o n of o b e s i t y t o r i s k of angina and sudden death w a s independe n t of blood p r e s s u r e and c h o l e s t e r o l l e v e l s . The Framingham study of 5,127 s u b j e c t s can f i n d no d i f f e r e n c e i n mean cholesterol-phospholipid r a t i o between those who developed coronary d i s e a s e and those who d i d n o t . S c h i l l i n g and co-workers,4 i n a study ofZ100 men and women of ages 18 t o 65, found t h a t t h e t r i g l y c e r i d e curve ( p l o t t e d a g a i n s t ,age) w a s p a r a l l e l t o serum c h o l e s t e r o l i n t h e female while i n t h e male it deviated. I n precoronary and postcoronary p a t i e n t s t r i g l y c e r i d e l e v e l s were higher t h a n i n normal s u b j e c t s . They conclude t h a t v a r i a t i o n i n l e v e l s of serum t r i g l y c e r i d e i s more c l o s e l y r e l a t e d t o coronary a r t e r i a l (disease than v a r i a t i o n s of serum c h o l e s t e r o l l e v e l s .
188
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Metabolic & Endocrine
H e i n z e l m a n , Ed.
F u r t h e r evidence has been presented t h a t a s t r o n g a s s o c i a t i o n e x i s t s between smoking and a t h e r o s c l e r o s i s . Increased m o r t a l i t y i s seen i n smoker^',^ although t h e c o r r e l a t i o n between smoking and serum l i p i d p a t t e r n s i s not c l e a r . A study by t h e Health Insurance Plan of Greater New York7 has shown t h a t p h y s i c a l a c t i v i t y plays a r o l e . The l e a s t a c t i v e smoker has an incidence of r a p i d l y f a t a l myocardial i n f a r c t i o n which i s nine timethat found among t h e most a c t i v e smokers. A r a p i d r i s e i n free f a t t y a c i d i s seen’ and an enhanced u t i l i z a t i o n of f a t t y acids’ occurs i n smokers apparently due t o n i c o t i n e i n g e s t i o n . The r e l a t i o n s h i p of t h i s f a t t y a c i d rise t o myocardial i n f a r c t i o n i s uncertain.
Diet - That
serum l i p i d l e v e l s can be manipulated t o some degree by d i e t a r y methods alone has been known for some time. The problem i s t h e design of a d i e t which i s acceptable t o t h e p a t i e n t . The design of such a d i e t has r e c e n t l y been d i s c u s ~ e d . ~ It has a moderate f a t content (3O$ of c a l o r i e s ) containing 10% saturates and 13%polyunsaturates. The e f f e c t i v e n e s s of adherence t o a “prudent d i e t ” i s seen i n t h e Anticoronary Club s t u d y l o which r e p o r t s that t h e prevalence of o b e s i t y , hypertension and hypercholesteremia were s i g n i f i c a n t l y reduced during t h e f i r s t f o u r years of t h i s program. The authors a l s o p r e s e n t d a t a showing a decrease i n new coronary d i s e a s e events i n t h e study group, although as y e t t h e s e numbers a r e r e l a t i v e l y small.
Engelberg” has shown t h a t t h e i n t r o d u c t i o n of highly unsaturated f a t s t o t h e d i e t lowers t r i g l y c e r i d e l e v e l s and increases t h e r a t e o f l i p o l y s i s i n normal a d u l t s . There w a s no change i n l i p o l y s i s r a t e i n p a t i e n t s i n whom t r i g l y c e r i d e l e v e l s d i d not decrease. This provides f u r t h e r evidence t h a t l i p o p r o t e i n l i p a s e i s t h e major physiological pathway f o r t h e removal of endogenously synthesized t r i g l y c e r i d e s from t h e blood stream and provides an explanation f o r t h e triglyceride-lowering a c t i o n of unsaturated f a t s . The e f f e c t of d i e t a r y carbohydrate on serum l i p i d l e v e l s is under extensive ~ t ~ d y l ~ , ~ but ~published , ~ ~ , ~ information does not permit p o s i t i v e c o r r e l a t i o n s as y e t . C o r r e l a t i o n s between c o f f e e drinking and e l e v a t e d serum l i p i d concent r a t i o n s were found i n men with coronary h e a r t d i s e a s e b u t not i n Caffeine has been shown t o e l e v a t e f r e e f a t t y a c i d s healthy controls.” This e l e v a t i o n i s suppressed by t h e i n t h e human and i n t h e dog.” a d m i n i s t r a t i o n o f sucrose. The authors f e e l t h a t c a f f e i n e e l e v a t e s FFA by a mechanism d i f f e r e n t from adrenaline or n i c o t i n e and may be a d i r e c t & an influence on t h e adrenal c o r t e x . e f f e c t on f a t pads and y D r u g s Affecting Serum Lipids - Because c h o l e s t e r o l i s t h e p r i n c i p a l component of t h e atheromatous plaque, measures t o reduce t h e l e v e l of c h o l e s t e r o l i n t h e blood by drug therapy may reasonably be expected t o prevent, or a t least r e t a r d , t h e development o f a t h e r o s c l e r o s i s . The most important drugs a v a i l a b l e today have been reviewed recently.20 The National Lipid Lowering Study, whose i n t e n t i s t o e v a l u a t e t h e e f f e c t s of c h o l e s t e r o l lowering drugs on t h e prognosis of coronary d i s e a s e , i s j u s t g e t t i n g underway. The study a n t i c i p a t e s a t o t a l of 8,000 p a t i e n t s
~ , ~
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Ath ero s cl ero si s
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to be studied for ten years and end points to be measured are the incidence of secondary myocardial infarctions, stdkes o r death. The drugs entered into the program at the moment are D-thyroxin, nicotinic acid, Clofibrate (CPIB) and Premarin. The fate of agents which inhibit cholesterol biosynthesis and accumulate sterol intermediates is still debated. No direct link between desmosterol build-up and the profound side effects of triparanol (lenticular cataracts, alopecia and ichthyosis) have been demonstrated. Recent reports have indicated that triparanol (MER-29) increased the incidence of aortic lesions in gerbilsJ21 improved atherosclerotic symptoms in pigeons,22 and in man,23 for periods up to sixteen weeks, lowered blood pressure, levels of serum cholesterol and produced improved cardiac function. Other agents which accumulate desmosterol continue to and appear. A large series of A- and B-ring-modified azachole~terols~~ cholesterol analogs with oxa- and oxa-aza side chains2' have been reported. The cholesterol lowering agent AY-9944 (1)has been studied extensively in the rat,26 pig,26c dog26c and cockerel.27 It inhibits the conversion of 7-dehydrocholesterol to cholesterol and cholesterol levels in the senun, liver, adrenals, kidney and aorta are decreased while the precursor levels are increased.26b The compound has been used as a tool to study the course of cholesterol biosynthesis." Study of a series of structural analogs has allowed a definition of the structural requirements for this type of activity.2s
A large series of biphenylyl-substituted compounds was tested 2
vitro for inhibition of the synthesis of cholester01.~~5-(&-Biphenylyl)-
3-methylvaleric acid (W 2531) (2) and P-(dimethylamino)ethyl 5-(4biphenylyl)-3-methylvalerate hydrochloride (W 2795) were the most potent inhibitors. W 2531 inhibits the incorporation of acetate into cholesterol and lowers serum cholesterol in the rat31 but not in the dog.32
1
w C H $ H & H (
2
3
CHs)CHpC02H
190 -
Sect. IV
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Metabolic & Endocrine
Heinzelman, Ed.
Studies on the action of Benzyl N-Benzyl carbethoxyhydroxamate (W 398) ( 4 ) showed an accumulation of cholesterol in the liver with no effect on serum cholesterol levels. It is suggested that the drug inhibits the transfer of cholesterol from the liver to the blood.33 Phenformin continues to show interesting effects on serum lipids in addition to its antidiabetic action. It produces lowered serum cholesterol and triglyceride levels in man.34 No effect on lipolysis has been seen in rats.35 These effects are not detectable with other antidiabetic agents such as Tolbutamide and Tolazamide 36
.
Atromid S (CPIB, ethyl chlorophenoxyisobutyrate) has now been released for sale in the U.S.A. Reports of its effectiveness in lowering serum triglycerides and serum cholesterol continue to appear.37 It has shown effectiveness in the diabetic38 with concomitant disappearance of retinal exudates.38a In combination with Thyroxine the two drugs complement one another.39 Fibrinogen levels have been lowered dramatically when CPIB This was given to patients with coronary t h r o m b o ~ i s . ~ ~ effect on fibrinogen could not clearly be related to its cholesterol lowering property. The drug appears to lower free fatty acid levels in man41 but an inhibitorj effect on lipolysis in rat epididymal adipose tissue could not be detected.42 Concern over the hepatomegaly produced by CPIB has prompted extensive study of the effects of the drug on the liver. This increased liver weight seems to disappear on chronic administration in the monkey and Microbodies appear in the liver simultaneously with the appearance of hy-p~lipidemia~~ suggesting a relationship between microbodies and lipid metabolism. Other agents which have shown activity in experimental animals include phenyramid01~~ which appears to inhibit hepatic microsomal enzymes, obenzoylthiamine disulfideP6 a series of pyrimidine-5-acetic acid derivat i v e ~ the , ~ ~antifertility agent 447a and chondroitin sulfate A,48 which is said to afford protection against coronary atherosclerosis. Three butyrophenones, wY-6123 (5), WY-3457 ( 6 ) and Trifluperidol (7)were studied in humans.49 WY-3457 had been reported earlier to inhibit cholesterol synthesis and to produce ichthyosis. WY-6123had little effect on cholesterol levels but Trifluperidol had a marked effect in
4
bCH3
Atherosclerosis
Chap. 18
Ursprung
191 -
7
5
6
CH2OCONHCH3
8 lowering c h o l e s t e r o l l e v e l s and a f t e r 5 months t h e r e has been a complete absence of s k i n and h a i r changes. Roniacol (f3-pyridylcarbinol) when given t o p a t i e n t s f o r 6 months produced a marked reduction i n f a t t y a c i d e s t e r s and c h o l e s t e r o l . Nicotinic a c i d produced s i m i l a r r e s u l t s b u t Fyridinolcarbamate t h e authors claim Roniacol gave fewer s i d e - e f f e c t s . ( 8 ) , an a n t i b r a d i k i n i n agent, i s reported t o prevent atheromatous changes i n t h e rabbit.’I I n mans2 t h e agent i s reported t o have a d e f i n i t e a n t i a n g i n a l e f f e c t along with a host of o t h e r r e a c t i o n s , including antiinflammatory and a n a l g e s i c responses. A very promising method of lowering serum c h o l e s t e r o l appears i n t h e b i l e a c i d sequestering agents. The m a t e r i a l which has received most c l i n i c a l work, cholestyramine, an anion exchange r e s i n , sequesters b i l e a c i d s from t h e gut, s t i m u l a t i n g c h o l e s t e r o l degradation a n d consequently a l s o c h o l e s t e r o l s y n t h e s i s . The r a t s 3 and. pig’* a r e a b l e t o synthesize c h o l e s t e r o l r a p i d l y enough t o compensate f o r t h i s b i l e a c i d d r a i n while t h e chicken and human cannot,and t h e r e f o r e show a decreased l e v e l of serum c h o l e s t e r o l and o t h e r l i p i d s . 5 5 This e f f e c t can a l s o be produced simply by T-tube drainage of t h e b i l e . 5 6 The drug has some e f f e c t on removal of f a t t y a c i d s , 56athyroxine, 57 porphyrinsS8 and f e c a l nitrogen” b u t a t e f f e c t i v e doses t h e r e appears t o be no c l i n i c a l problem. The development of g a l l s t o n e s has been reported i n guinea pigs6’ with t h e use of t h i s drug but a t t h e same time neomycin, which a l s o s e q u e s t e r s b i l e a c i d s , i s reported61 t o prevent c h o l e s t a n o l induced g a l l s t o n e s i n t h e r a b b i t . Cholestyramine has found c l i n i c a l use i n t h e r e l i e f of p r u r i t i s 6 2 of b i l i a r y c i r r h o s i s and p s o r i a s i s . Other agents which have been shown t o remove b i l e a c i d s e f f e c t i v e l y a r e neomycin and N-methylated neomycin,63 ’ t h e azacholestane 9.66 t h y r o i d hormones,64 DEAE S e p h a d e ~ , ~and
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Metabolic & Endocrine
Heinzelman, Ed.
c)
NHCO (CH2)7(CH=CHCH2)2Bu
CH3 CH3
10
9
Several agents which inhibit absorption of cholesterol have also been studied as cholesterol lowering agents. These include N-cyclohexyllinoleamide (Linolexamide) (10)67 diosgenin, pectin6’ and a variety of mucilaginous polysaccharides 70
.
The influence of lipolysis inhibitors continues to be studied vigorously but their influence on the atherosclerotic process is uncertain. Nicotinic acid and various derivatives is the subject of many communication^.^^ It has been shown to prevent the FFA rise caused by smoking in humans .72 Perhaps the most interesting lipolysis inhibitor at the present time is prostaglandin which is extremely active at a very low dose level. The effect of the @-blocking agent Propranolol has been studied in acute myocardial infarction and found to be of no value.74 It appears to have some benefit in angina pectoris7’ but its side effects are severe. Hormones - A more detailed account of the effect of estrogen on lipids and its protective effect on coronary atherosclerosis in the cockerel has been published.76 This same protective effect on the coronaries is also reported in the cholesterol-fed pigeon.77 A suggestion has been made that the female aorta under the influence of estrogen has a greater “healing-power‘‘of the vascular connective tissue than the male aorta.78 Evidence has been presented that patients with coronary artery disease have a higher ratio of estrone to estradiol than normals suggesting that estradiol may indeed be a protecting factor in the disease.79 The search for estrogens having a greater effect on lipids than on the uterus continues .*O 162-chloro-estrone-~-methylether has shown no effect in humansa1 while the steroid 11 appears to have a rather large split between its hypocholesteremic and uterotropic responses in the rat.82 The various esters of nicotinic acid with estradiol have been studied extensively but appear to be uterotropic .83
Chap. 18
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U 1-s p r u n g
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A s e r i e s of thyroxine analogs having s t r u c t u r e 1 2 have been synthes i z e d and evaluated f o r hypocholesteremic a c t i v i t y . 8 4 No promising candidates a r e apparent. a-Methyl MI3 and DT4 have been prepared but show only a weak hypocholesteremic response i n Negative r e p o r t s on the\ e f f e c t i v e n e s s of thyroxine a r e beginning t o appear. C h o l e s t e r o l f e d cockerels a r e not p r o t e c t e d a g a i n s t coronary a t h e r o s c l e r o s i s by Dand L-Thyroxine,86 and i n f a c t t h e t h y r o i d hormone may enhance t h e development of c h o l e s t e r o l a t h e r o s c l e r o s i s i n t h e r a b b i t d e s p i t e a preliminary r e p o r t a l s o f i n d s lowering of serum c h o l e ~ t e r o l . A~ very ~ no change i n m o r t a l i t y or morbidity i n humans t r e a t e d with D-thyroxine.88 The r o l e of antiinflammatory drugs i n t h e treatment of a t h e r o s c l e r o s i s i s s t i l l being i n v e s t i g a t e d . Cortisone a c e t a t e has been shown t o reduce t h e development of plaques i n c h o l e s t e r o l - f e d r a b b i t s by about 754'0.89 Phenylbutazone w a s a l s o e f f e c t i v e b u t a s p i r i n w a s not. Cortisone d i d not cause r e g r e s s i o n of a l r e a d y formed plaques i n d i c a t i n g t h a t t h e a c t i o n of t h e drug i s i n t h e e a r l y s t a g e s of plaque formation through i t s antiinflammatory p r o p e r t i e s r a t h e r t h a n through any lipemic e f f e c t s . Thrombosis and F i b r i n o l y s i s - P l a t e l e t adhesiveness i s mediated by ADP. Release of ADP from t h e p l a t e l e t causes aggregation." This response i s i n h i b i t e d by ATP. The mechanism proposed f o r t h e clumping reaction" i s that ADP i n h i b i t s t h e s p l i t t i n g of ATP t o ADP, a r e a c t i o n which otherwise occurs through p l a t e l e t membrane ATPase which u s u a l l y keeps t h e p l a t e l e t i n an unsticky s t a t , e . I n h i b i t i o n of t h i s ATPase by ADP l e a d s t o t h e exposure of adhesive s i t e s and permits p l a t e l e t aggregation. C e r t a i n physiologic and d i e t a r y m a t e r i a l s a f f e c t t h e p l a t e l e t react i o n s . Catechol amines enhance p l a t e l e t aggregations2 and promote thrombus formation. 93 F a t t y a c i d s appear t o enhance p l a t e l e t aggregat i o n , with s a t u r a t e d f a t t y a c i d s being more e f f e c t i v e t h a n u n s a t u r a t e d f a t t y acids.s4 Thrombosis i s produced i n t h e dog by s i n g l e r a p i d i n f u s i o n of long-chain s a t u r a t e d f a t t y acidss5 b u t chronic slow i n f u s i o n s a r e nonthrombogenic. 96 Apparently t h e dog has s u f f i c i e n t thrombolytic power t o handle t h e l a t t e r s i t u a t i o n . L i t e r a t u r e on t h e e f f e c t s of dextran on p l a t e l e t adhesiveness i s c o n t r a d i c t o r y . The method of measurement i s important. It appears t o reduce p l a t e l e t adhesiveness t o glasss7 b u t has no e f f e c t on ADP-induced I t s e f f e c t i n humans i s e q u a l l y confused. 99 Although aggregation. it may p l a y a r o l e i n surgerylo0 and c e r t a i n occlusive v a s c u l a r diseases,lol it appears t o have no b e n e f i t i n a c u t e myocardial i n f a r c t i o n . l o 2 Atromid S reduces p l a t e l e t adhesivenesslo3 and i n c r e a s e s bleeding timelo4 i n man. E s t r i o l , i n man, has no e f f e c t on p l a t e l e t adhesion.lo5 A l a r g e s e r i e s of guanidino compounds has been s t u d i e d and found t o be a c t i v e i n h i b i t o r s of ADP-induced p l a t e l e t aggregation.lo6 Some of t h e most a c t i v e a r e 6 -guanidinovaleric acid, p,p' -diguanidinodi.phenylsulfone and p,p'-diguanidinodiphenylmethane. Other agents which have shown some a c t i v i t y a r e N-Ethylmaleimidelo7 and a s e r i e s of membrane-active drugs,lo8 such as chlorpromazine, imipramine, n o r t r i p t y l i n e , e t c . Prostaglandin El
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Sect. IV - Metabolic & Endocrine
Heinzelman, Ed.
has been shown to reduce clotting time very markedly in rats.”’
A study in coronary patients has shown that fibrinogen levels are increased over normal controls’” and that fibrinolytic activity is also decreased in these patients .I1’ The rate of degradation of fibrinogen is inhibited in rats fed En atherogenic diet.l12 It would seem reasonable then that some control over the clinical outcome of atherosclerosis could be had by the use of fibrinolytic agents. The enzymes streptokinase and urokinase continue to be eval~ated’’~with some benefits Phenforminl” is reported in the therapy of acute Thromb~embolisrn.’~~ still the only drug of interest as a fibrinolytic agent other than the enzymes and CPIB mentioned earlier. Psycho-Social Factors - One’s personality and environment greatly Personality type A influence his prognosis of coronary thrombosis.’16 individuals are highly prone while the fully developed type B are essentially immune to the disease’17 provided their serum lipids are not abnormal. Seemingly healthy individuals exhibiting type A behavior exhibit a serum lipid pattern similar to that found in persons suffering from coronary artery disease. They exhibit abnormal preprandial and postprandial values of serum triglycerides while blood sugars are normal?-’’ This triglyceride response can be controlled by the administration of corticotr~pin,~’~ which acts apparently by augmenting the adrenal discharge of hormones. The mechanisms involved in the lipid responses of behavior type A remain uncertain. Summary - Knowledge in the field of atherosclerosis is expanding at a very rapid rate. There seems to be sound evidence that vigorous dietary measures along with the use of drugs can bring serum lipid levels to a “normal“ value and that, with these measures, a considerable majority of coronary heart disease and atherosclerosis cases may be prevented. The Anti-coronary Club study lends support to this statement and hopefully the National Lipid Lowering Study, just getting underway, will provide conclusive evidence on this point. The release of Atromid S to the U.S. market provides a powerful tool to the physician in his fight against coronary artery disease. A very promising method of treatment is emerging in the use of bile acid sequestering agents. This therapy provides safety along with a method of lowering cholesterol levels which is highly physiologic in nature. Study of the mechanism of thrombosis and its inhibition by drugs affecting platelet aggregation i s proceeding at a rapid rate and shows great promise for future application. The application of Prostaglandin El, a material occurring naturally in humans, in this area is an intriguing possibility. The study of atherosclerosis and its prevention remains one of the most vigorous and perhaps one of the most important areas in medical research.
Chap. 18
U r sprung
Atherosclerosis
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References 1
W . P . C a s t e l l i , W . B. Kannel, and D. S h u r t l e f f , C i r c u l a t i o n ,
71(1966)
2 3 4.
5. 6. 7. 8.
2,S u p p l .
111,
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118,
a,
Chapter 19. Reproduction Daniel Lednicer, The Upjohn Company, Kalamazoo, Michigan Introduction - At first sight, the intricate process of mammalian reproduction would appear vulnerable to interuption by outside agencies at numerous points. In the female, for example, one could, at least in principle, prevent ovulation, sperm capacitation, transport of that sperm to the oviduct, penetration of the egg by sperm, division of the fertilized egg, transport of the egg to the uterus, or even finally nidation. The developmental process of the male germ cell from the spermatogonium to a mature sperm cell would also appear to offer numerous points of attack. Despite this, the only practical means of chemical contraception as of this writing consists of estrogen progestin type of oral contraceptives. Though much effort has been expended in the search for some means of contraception which does not involve the pituitary, such an agent has not yet been found. Steroids - The steroidal oral contraceptives now available in the U. S. have recently been reviewed' as has the chemical development ofthese drugs.2 The belated recognition of the importance of the estrogen component of these formulations has led to the development of the so called sequential agents; studies seem to indicate that better control of intramenstrual bleeding is achieved w i t h the I' sequentials r'3,4 J' than with the combination drugs. The finding that certain progestins had long lived action when administered parenterally has led to the development of injectable long acting contraceptives; one of these (medroxyprogesterone acetate) is administered as the pure progestin,6 the other (dihydroxyprogesterone acetophenide) is given with an injectable estrogen (estradiol enanthate).7 Interestingly, some clinical success has been realized in achieving-contraception with an orally administered pure estrogen (diethyl stilbestrol)8 or a pure progestin (chlormadinone) in low dosage.' Apparent exceptions to the rule that a saturated A ring is necessary for progestational activity have been reported recently. Thus, compound 1 was shown to exhibit weak activity in the Clauberg assay'' vhile 2 showed good activity in inducing arborization of rabbit uterine epithelium;11,12 the observation that 2 is uterotropic 3s well,
20 0 -
Sect. I V - M e t a b o l i c & E n d o c r i n e
H e i n z e l m a n , Ed.
s u g g e s t s t h a t a s i n g l e compound estrogen-progestin contraceptive i s i n t h e realm of p o s s i b i l i t y . The search f o r s t e r o i d s with non-classical b i o l o g i c a l s p e c t r a included t h e preparation o f t h e modified s t e r o i d s 3 t o 10. The b i o l o g i c a l a c t i v i t i e s a r e surmnarized i n Table I.
OH
OH
4
3
OH
R
5; A8,14,
R
= 0
6 ; R = O OH / 7 ; R =. B
9
10
Reproduction
Chap. 19
Lednicer
20 1 -
Table I B i o l o g i c a l A c t i v i t i e s of S e l e c t e d S t e r o i d s Compound
References
13 14 15 15 15 16 17 18
9 10
Biological Activity
5% of Progesterone; Clauberg very weak estrogen u t e r o t r o p i c ; .01% e s t e r o n e u t e r o t r o p i c ; .03$ e s t e r o n e u t e r o t r o p i c ; 0.6% e s t e r o n e gonatropin i n h i b i t o r ; low u t e r o t ropic a c t i v i t y antiestrogen; antiprogestin, progestin
Compounds Related t o Triphenylethylene - Derivatives of t h i s c l a s s of s y n t h e t i c estrogens continue t o be an area of i n t e r e s t f o r t h e preparat i o n of p o t e n t i a l a n t i f e r t i l i t y agents. Thus, compounds llJ1’ 12,20 and 1321 are a l l reported t o possess u t e r o t r o p i c a c t i v i t y , t h e pQtency depending on t h e s u b s t i t u t i o n p a t t e r n . No b i o l o g i c a l d a t a a r e a v a i l a b l e f o r 14.22 The incorporation o f a b a s i c e t h e r i n t o t h e n i t r o t r i a r y l ethylene 1523 l e d t o a potent o r a l a n t i f e r t i l i t y agent; t h i s compound (CN-55,945-27) w a s shown t o be an estrogen antagonist24 and t o be Replacement e f f e c t i v e probably because of t h i s a n t a g ~ n i s r n . ~ ~ o f the n i t r o group i n 1.5 by an e t h y l s i m i l a r l y l e a d s t o an estrogen a n t a g o n i s t . I n t h i s case, however, t h e cis and trans isomers (16, 17)26 showed markedly d i f f e r e n t b i o l o g i c a l p r o p e r t i e s ; t h e cis compound ( I C 1 47, 699; 17) behaved as a conventional estrogen while t h e trans compound ( I C 1 46, 474; 16) w a s a weak estrogen and antagonized t h e e f f e c t of concomittantly administered estrogen.27 I n puzzling c o n t r a s t t o t h i s , t h e isomers of 15 show i d e n t i c a l a n t i f e r t i l i t y a c t i v i t y , 2 3 and t h e corresponding isomers of 1 2 show t h e same antigonadotropic potencies .20 R1
R1 . R2
Rs
11
R1 = HJCF3
R2 = CF3 R3 = CH3,OCHz
12
20 2 -
Sect. IV
-
Metabolic & Endocrine
Heinzelman, Ed.
y R1
R2
k3
13
14
R1,R2 and/or R3
R1 = H,OCH3 R2 = H,Cl,OC&
= OCH3
X = Br,C1
trans
/
( CH3 ) 2NCH2CH20
17 cis -
A series of chromenes and chromans (18, 19 d 20), analogous to previously recorded tetrahydronaphthalenes,28 has been reported;29 compound 19 [cis,R=OCH$H2N(CH2H5)z] was the only one to show activity as an antifertility agent at 1 mg./kg. Replacement of a methylene by nitrogen similarly leads to attenuation of potency; thus, only one [ 2 3 , of a series (21-24)of indoles showed R1=R2=R4=H; R3=OCH2CH2N( C2HS) antifertility activity.30 The tetrahydronaphthols 25 and the dihydronaphthalenes represented by 26 were all shown to be potent estrogens;31 in contrast to this, the glyceryl ether 27 showed many of the estrogen antagonistic properties characteristic of the previously reported basic ether.32 Attempts to simplify these molecules by replacement of the phenyl at the 1 position by vinyl and ethynyl (28) led to a series of inactive compounds.33
Reproduction
Chap. 19
Ledni c e r
20 3 -
18; R = H,CH~,CH~CHZN(C~H~)~ 21; R1 = OCH2CH2N(C2H5)2; R2,R3,R4 = H,OCH3 c i s diphenyl; R = H,CH3, 19; -
-
20; t r a n s diphenyl; R
CHPCH~N(C~H~)~ 22; R2 = OCH~CH~N(C~H~)Z; = H,CH3, R1,R3,R4 = H,OCH3 C H Z C H ~ N ( C ~ H ~23, ) ~ R3 = O C H Z J ~ ~ ~ " ~ C ~ H S ) ~ ; R1,R2,R4 = H,OCH3 24; R4 = OCHZCH~N(C~H~)~; R1,R2,R3 = H,OCH3 R
25; R
=
H,CH3,F
CH30
J33
C6H5
\
26; R 27; R
= =
H,CHs,F,OH OCH2CHOHCH20H
29; R
=
H,OCOCH3
rnC\ 6.".
X 28; R = -CH=CH2,-CECH X = CH2,O
The cyclohexylidene 29, has been reported t o be a weak estrogen, e f f e c t i v e as an a n t i f e r t i l i t y agent, which w i l l under c e r t a i n conditions exhibit antiestrogenic activity.34 Miscellaneous S t r u c t u r a l Types - The oxazolidine t h i o n e 30 (U-11,634) w a s r e -p o r t e d t o be an e f f e c t i v e a n t i f e r t i l i t y agent i n t h e rat.35 It w a s shown t o be devoid of hormonal p r o p e r t i e s and t o suppress t h e deciduomata development i n a traumatized u t e r u s .36 The dibenzodiazocine 3137 caused complete i n h i b i t i o n of f e r t i l i t y i n rats a t 2.5 mg./kg. i n t h e
Sect. I V - Metabolic & E n d o c r i n e
20 4
I
H e i n z e l m a n , Ed.
r a t ; t h e d e m o n ~ t r a t i o nt ~h ~ a t t h i s compound behaves as an estrogen on s e v e r a l endpoints seems t o account f o r t h i s a c t i v i t y . A u t e r o t r o p i c f a c t o r from s p o i l e d grain3' has been i s o l a t e d ; s t r u c t u r a l e l u c i d a t i o n
30
33 C ECH
34
35
showed t h i s compound (zearalenone) t o be t h e macrocyclic l a c t o n e 32.40 This c l a s s of compounds has been reported capable of c o n t r o l l i n g animal f e r t i l i t y . 4 1 A p o t e n t i a l approach t o a p o s t c o i t a l " p i l l " comes from t h e f i n d i n g t h a t t h e n o n s t e r o i d a l estrogen 33 e f f e c t i v e l y prevented pregnancy i n t h e rhesus monkey when administered a t 10 mg. p e r day for 6 days following mating.42 The perhydro phenanthrene 34 (Ro 5-2537) shows i n t e r e s t i n g s t e r o i d a n t a g o n i s t i c p r o p e r t i e s i n that it w i l l i n h i b i t t h e u t e r o t r o p i c e f f e c t of s t i l b e s t r o l b u t only minimally t h a t of e s t r a d i o l ; t h e compound a l s o i n h t b i t s t h e stirnulatory e f f e c t s of androgens i n t h e male.43 The p o s s i b l e s i g n i f i c a n c e of such an agent i n reproductive processes i s not known. Induction of Ovulation - F a l l o u t f r o m t h e recent emphasis on work on a n t i f e r t i l i t y has,been a t o o l f o r t h e treatment of i n f e r t i l i t y due t o ovulatory f a i l u r e . The use of clomiphene c i t r a t e ( 3 5 ) f o r t h i s c l i n i c a l condition has met with a good measure of a double b l i n d study demonstrated t h a t t h e response w a s indeed a drug e f f e c t . 4 5 Though t h e exact mechanism o f a c t i o n of t h i s agent i s not c l e a r , it has been shown t o i n c r e a s e t h e estrogen output i n women without i n c r e a s i n g u r i n a r y gona-
Chap. 1 9
Reproduction
L e dni c e r
20 5 -
dotropins.46 An a l t e r n a t e approach t o induce ovulation involves t h e use of human gonadotropic preparations. 47, 48 Refractory cases have been s u c c e s s f u l l y t r e a t e d with a combination of clomiphene and gonadotropins .4s B i o l o g i c a l Considerations - Progress i n t h i s a r e a as i n many o t h e r s depends Qn developing a c l e a r e r understanding of f i n e r d e t a i l s of t h e hormonal mechanisms involved i n both t h e normal processes and i n drug a c t i o n . The a v a i l a b i l i t y of radioimmune assays for human serum LH5'j5l and for u r i n a r y FSK52 should h e l p provide information on t h e a c t i o n of drugs a t t h e p i t u i t a r y l e v e l . I n an e l e g a n t piece of work, t h e u t e r i n e estrogen receptor was r e c e n t l y i s o l a t e d i n highly concentrated form.'3 The r o l e of t h e hypothalmus i n t h e r e g u l a t i o n of t h e reproductive cycle i s coming under i n c r e a s i n g l y i n t e n s i v e i n v e s t i g a t i o n ; t h e a c t i o n o f hormones on t h i s e n t i t y has r e c e n t l y been reviewed.'* Considerable progress i s being achieved towards t h e i s o l a t i o n of t h e hypothalamic r e l e a s i n g f a c t o r s f o r t h e p i t u i t a r y hormones .'5 Summary - The means f o r chemical contraception a r e now a t hand, with
various estrogen p r o g e s t i n regimes. Considerable c l i n i c a l and b i o l o g i c a l e f f o r t i s devoted t o f i n d i n g new and more convenient means of employing t h e s e hormonal agents. The success achieved with p o s t c o i t a l l y admini s t e r e d estrogens may l e a d t o a p o s t c o i t a l p i l l . Despite a l a r g e amount of both chemical and b i o l o g i c a l work on compounds which may be l o o s e l y termed estrogen a n t a g o n i s t s , no n o t i c e of c l i n i c a l success of such an agent has as y e t appeared. An i d e a l agent f o r achieving contraception would be one which completely bypassed t h e endocrine system; t h i s breakthrough i s s t i l l t o come. The i n t e n s i v e work on t h e endocrinology of reproduction i s bringing c l o s e r t h e day when t h e process w i l l be f u l l y understood
.
Sect. I V
20 6 -
- Metabolic
& Endocrine
H e i n z e l m a n , Ed.
References
1. L. F. Tice, Am. J . Pharm., 2.
3-
4.
7.
1-38,
104(1966) C . D j e r a s s i , Science, 1055(1966) G. Oclander, Can. Med. Assoc. J . , 94,218(1966) E. C . Jungck, Am. J . Obstet. Gynecol., 94,165(1966) J . A. Board and D. S. Borland, F e r t i l i t y and S t e r i l i t y , 1-7, 234(1966) E. M. Coutinho, J . C. deSouza, and A. I. Csapo, F e r t i l i t y and S t e r i l i t y , 1-7, 261 (1966) T. H. Rizkallah and M. L. Taymor, Am. J . Obstet. Gynecol., 94,
151,
161(1966)
8. E. 9. J.
B. Middleton, O b s t e t r i c s and Gynecology, 26, 253(1965) Martinez-Manautou, V. Cortez, J . Giner, R. Aznar, J . Casasola, and H. W. Rudel, F e r t i l i t y and S t e r i l i t y , 49(1966) 10. L. J. Chinn, J . Med. Chem., 9, 602(1966) 11. R. E. Counsell, P. D. K l i m s t r a , R. L. Elton, and E. F. Nutting, J. Med. Chem., 9, 689(1966) 12. R. L. Elton, R. E. Counsell, P. D. K l i m s t r a , and E. F. Nutting, Experientia, 22, 437(1966) 13. G. C. Buzby, Jr., E. Capaldi, G. H. Douglas, D. Hartley, D. Herbst, G. A. Hughes, K. k d i g , J . McMenamin, T . P a t t i s o n , H. Smith, C . R. Walk, G. R. Wendt, J . S i d d a l l , B. Gadsby, and A. B. A. Jansen, J . Med. Chem., 2, 338(1966) 1 4 . D. F. Morrow and R. M. Hofer, J. Med. Chem., 2, 249(1966) 1 5 . G. H. Douglas, C . R. Walk, and H. Smith, J . Med. Chem., 2, 27(1966) 16. E. Farkas, J . M. Owen, M. Debono, R. M. Molloy, and M. M. Marsh, Tetrahedron L e t t e r s , 2, 1023(1966) 1 7 G. Bialy, A. P. M e r r i l l , and G. Pincus, Endocrinology, 79, 125(1966) 18. G. A. Boswell, Jr., J . Org. Chem., 2, 991(1966) 19* Ng. Ph. Buu Hoi, N. H. N a n , and N. D. Xuong, Rec. Trav. Chim. Pays. Bas., 367(1966) 20. H. H. FOX, J . T. Gibas, H. L. Lee, and A. Boris, J . Med. Chem.,
17,
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3,
8, 415(1965)
21.
5.
22.
176( 1966) L. N. Volovelskii and V. G. Khukhryanskii, Zhur. Org. Khim., 1688(1966)
23 24. 25 * 26. 27 * 28.
R. Dice, L. Scheinman, and K. W. Berrodin, J . Med. Chem.,
2,
2,
H. A. DeWald, 0 . D. Bird, G. Rodney, D. H. Kaump, and M. L. Black, Nature, 2,538( 1966) M. R. C a l l a n t i n e , R. R. Humphrey, S. L. Lee, B. L. Windsor, N. H. S c h o t t i n , and 0 . P. O'Brien, Endocrinology, 79, 153(1966) M. R. C a l l a n t i n e , R. R. Humphrey, and B. L. Nesset, Endocrinology,
79,
455(1966)
G . R. BeSiford and D. N. Richardson, Nature, 212, 733(1966) M. J . K. Harper a,nd A. L. Walpole, Nature, @, 87(1966) W. L. Bencze, R. W. J . Carney, L. I. Barsky, A. A. Renzi, L. Dorfman, and G. &Stevens, Experientia, 261(1965) R. W. J . Carney, W. L. Bencze, J . Wojtkunski, A. A. Renzi, L. Dorfman, and G. &Stevens, J . Med. Chem., 2, 516(1966)
g,
Chap. 19
31.
Reproduction
Lednicer
20 7
J . K. Landquist and C. J . Marsden, Chemistry and Industry, 3, 1032 (1966) D. Lednicer, S. C . Lyster, B. D. Aspergren, and G. W. Duncan, J . Med. Chem., 2, 172(1966) D. Lednicer, S. C . Lyster, and G. W. Duncan, J . Med. Chem., 10,
78(1967)
33. 34. 35.
36.
37. 38.
39. 40.
41. 42.
43. 44. 45.
46. 47. 48. 49. 50 *
51. 52
53.
54. 55.
G. &Stevens and B. Smolinsky, J . Med. Chem., 9, 954(1966) E. N. Jensen, Acta. Pharmacol. Toxicol., 23, 3Z5(1966) G. A. Youngdale, G. W. Duncan, D. E. Ehmert, and D. Lednicer, J . Med. Chem., 2, 155(1966) G. W. Duncan, J. C. Cornette, S. C. Lyster, J. I. Northam, and L. J. Wyngarden, Am. J. Physiol., 184(1966) W. Metlesics, T. Resnick, G. Silverman, R. Tavares, and L. H. Sternbach, J . Med. Chem., 2, 633(1966) G. W. Duncan, S. C. Lyster, and J. B. Wright, Proc. SOC. Exptl. Biol. Med., E, 725(1965) M. Stob, R. S. Baldwin, J . T u i t e , F. N. Andrews, and K. G. G i l l e t t e , Nature, @, 1318(1962) W. H. U r r y , H. L. Wehrmeister, E. B. Hodge, and P. H. Hidy, 3109(1966) Tetrahedron L e t t e r s , 3, J . A. Osmundsen, The New York Times, December 8, 1965, p. 69, 78. J . McL. Morris and G. Vanwagenen, Am. J . Obstet. and Gynecol., 804 (1966) A. Boris and R. H. Stevenson, Endocrinology, 78, 549(1966) M. J. Whitelaw, F e r t i l i t y and S t e r i l i t y , 9, $4( 1966) D. W. Cudmore and W. R. C. Tupper, F e r t i l i t y and S t e r i l i t y , 9,
211,
96,
363 (1966)
94,
0. W. Smith, Am. J. Obstet. Gynecol., 440(1966) C . Gemzell and P. ROOS, Am. J. Obstet. Gynecol., 94, 490(1966) C . Gemzell, F e r t i l i t y and S t e r i l i t y , 149(1 9 6 6 F R. W. Kistner, F e r t i l i t y and S t e r i l i t y , 569(1966) W . D. Odell, G. T. Ross, and P. L. Rayford, Metab. Clin. Exp., 15, 287 (1966) A. R. Midgely, Jr. and R. B. J a f f e , Abstracts, Endocrine S o c i e t y Meeting, Chicago, I l l i n o i s , June 1966 A. Wolf, Nature, p11, 942(1966) P. W. Jungblut and E. V. Jensen, Abstracts, Endocrine S o c i e t y Meeting, Chicago, I l l i n o i s , June 1966 K. Brown-Grant, B r i t . Med. Bull., 273(1966) A. V. Schally, T. S a i t o , A. Arimura, E. E. Muller, and C. Y. Bowers, Endocrinology, 79, 1087(1966)
1-7, 1-7,
z,
20 8
Chapter 20. Steroid Hormones and their Antagonists Patrick A. Diassi and Leonard J. Lerner, The Squibb Institute for Medical Research, New Brunswick, N. J. A bibliography of steroid conjugates’ as well as a treatise on the metabolism of steroid hormones2 have been published. The abstracts of papers presented at the Second International Congress of Hormonal Steroids are available3
.
Corticoids A possible explanation for the anti-inflammatory action of cortisol based on the prevention of release of plasma kinins has been published4. A number of 8-dehydro analogs of corticosteroids have been synthesized5 and their thymolytic and salt retaining properties measured. The compound found to have the highest thymolytic activity was 1 (11.4 x hydrocortisone). Again the fallacy of projecting biological activity from one series of steroids to another was demonstrated by the large decrease in activity exhibited by the 8dehydro steroid 2 as compared with 16a-methylprednisolone ( 3 ) . CH20R
CH2 OAc
I
I
2 3
R=Ac R = H, 8,g-dihydro
Chap. 20
Steroid Hormones
Diassi and L e r n e r
20 9 -
The 21-desoxy-16a,l7a-isopropylidenedioxypregnenes 4 and 5 show potent anti-inflammatory properties and the allylic alcohol 6 has water solubility and a partition coefficient (water-ether) which might predict a favorable percutaneous absorption6.
A number of 3-(2'-chloroethoxy)-6-formylpregn-3,5-dienes have been prepared7 of which 7 shows a marked dissociation of local and systemic anti-inflammatory activity. Both 1,4-dimthylestratrienes 8 and 9 are active in the carragenininduced foot edema rat assay at the subcutaneous dose level of 2 5 mg./rat8.
It has been proposed9 that there is a direct relationship between the inhibition of growth of mouse fibroblasts in vitro and the anti-inflammatory activity of llf3-hydroxylated steroids, ll-Ketosteroids do not show this inhibition and this may be due to the lack of enzyme systems necessary to convert ll-keto to llg-hydroxy steroidslO.
210 -
Sect. I V
-
Metabolic & Endocrine
Heinzelman, Ed.
Studies on the mechanisms regulating secretion of aldosterone and glucocorticoidsll and on the mode of action of aldosterone12 have been published. Proqestational Compounds The 16-methylene derivative (10) of chlormadinone (11) is twice as active as 11 in the modified Mc Phail assay on oral admini~trationl~. The deciduogenic activity of substituted estradiols has been used as another parameter for assessing intrinsic progestational activityl4,15,16. Both 17-(2-butenyl)-estradiol 3-acetate (12) and the 17-(2-methylallyl) derivative (13) were active in this assay. The totally synthetic 18-homolog 14 of norethisterone (15) has proven to be a potent progestational compound in a n i m a l ~ l ~ and , ~in ~ rnan19920,21. The 6a-methyl derivative 16 has 85 times the activity of 15 in the Clauberg assay22. (f)-18-Methyl-19norprogesterone (171 is a potent pr~gestogen~~.
OH
10 R = CH2 11 R = H2
&
CH3
I
.CZCH
17 H H
16
R1
C2H5,
R2 = CH3
Steroid Hormones
Chap. 20
Diassi and Lerner
21 1 -
Androcrens The effect of l-alkyl substitution in decreasing the androgenicity of a number of 5a-androstanes has been noted and a proposal regarding the structural requirements for biological activity of androgens has been made24. 17~-Trimethylsiloxytestosterone (18) has been shown25 to be more active on subcutaneous administration than testosterone. The prolonged duration of action of this compound has also been noted26. A new class of orally active alkyl steroid-17p-yl mixed ketals of aliphatic and cycloaliphatic ketones have been prepared27. A member of this series, 178- (l-methoxy-l-cyclohexyloxy)-3-propionyloxy-5a-androst-l-ene (19) shows greater androgenic activity than methyl testosterone.
19
18
An evaluation has been made of the nitrogen retention: androgenic and myotrophic:androgenic dissociation ratios of anabolic steroids2*. A number of new anabolic agents have been synthesized which have a good ratio of myotrophic to androgenic activity. These include 17a-methyl-androsta-1, 5-diene-38,17@-diol(2O) 29, 5a-estr-2-en-17p-01 (21)30 and its l7a-methyl derivative 22, the two 2a,3a-epithio-5aandrostanes 23 and 2431, the l-keto-5a-androstane 2532 and 17~-(l-methoxy-l-cyclohexyloxy)-androst-5(lO)-en-~-one (26)27.
17a-Methyl-4,9,11-estratriene-17~-01-3-one(27), a potent anabolic steroid, has been reported to produce liver toxicity with low dosage in humans3 3
.
212 -
Sect. IV
-
Metabolic & Endocrine
4 &* cH3
RS
Heinzelman, Ed.
-:&,?.
.R
H
20
21 22
R = H R CH3
23 24
R - H R = CH3
.CH3
26
25
27
EstroqenF The relative uterotrophic activities of *and 17-desoxy derivatives of estrone and estradiol and their alkyl derivatives hape been publishec13~. A comparison of the hormonal activities of some new 17a-haloethynyl steroids is also available35. The totally synthetic (f)-8arisomer 28 of 17f3-hydroxy17a-ethynylestr-5(10)-en-3-one (29) is about one-half as active as 2 9 in a pituitary blockage test36. l-Acetoxy-17~ethynylestradiol 3-acetate (30) is ten times as active orally as 17a-ethynylestradiol (31)37.
28
29
8a 8!3
Chap. 20
Steroid H o r m o n e s
D i a s s i and L e r n e r
21 3 -
Estradiol dipropionate has been shown to hasten brain maturation in new born rats38. It has been found that there is no necessary correlation between estrogen antagonism and progestational activity of steroids39. The spiran 32 exhibits very pronounced antiestrogenic activity40.
32 Insect Hormones The synthesis of ecdysone (33) the insect moulting hormone has been announced by two g r ~ u p s ~ ~ Furthermore j ~ ~ . isolations of 20-hydroxy-ecdysone (34) from silk worm43 (e~dysterone)~~, crayfish45 and oak-silk moth (crustecdysonep and tobacco h ~ r n w o r mhave ~ ~ been reported. Four compounds have been isolated48 from the leaves of Podocarpus nakaii Hay all of which have insect moulting activity. The structure proposed for ponasterone A is 35. Crustecdysone has been isolated from Podocarpus elatus, an Australian timber tree49. The ready isolation of these compounds from plants makes it possible to supply large amounts of active substances for biological testing.
33 34 35
R1 = H R2 OH 22 R1 = R2 = OH (C20 and C22 configurations undefined) Rl = OH (C20 and C22 configurations undefined) R2 = H
214 -
Sect. i V
- Metabolic
& Endocrine
Heinzelman, Ed.
The secretion of large amounts of cortexone ( 3 6 ) by the water beetle (Dytiscus maaginalis) as a defensive substance has been reported5'.
36
References 1.
S. Bernstein, E. W. Cantrall, J. P. Dusza and J. P. Joseph, "Steroid Conjugates", American Chemical Society, 1155 Sixteenth Street, N.W. , Washington, D. C.
2.
R. I. Dorfman and F. Ungar, "Metabolism of Steroid Hormones", Academic Press, New York, 1965. Second International Congress on Hormonal Steroids, Abstracts of Papers Presented, Excerpta Medica Foundaticn, New York Academy of Medicine Bldg., 2 East 103 Street, New York, N. Y. 10029, 1966. M. J. Cline and K. L. Melmon, Science, 153, 1135 ( 1 9 6 6 ) . M. Heller, R. H. Lenhard and S. Bernstein, Steroids, 1,
20036,
3.
4.
5.
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3 8 1 (1966). 6.
7.
8. 9.
R. Deghenghi, M. Boulerice, J. D. Rochefort, S. N. Sehgal and D. J. Marshall, J. Med. Chem., 2, 513 ( 1 9 6 6 ) . G. Baldratti, B. Camerino, A. Consonni, F. Facciano, F. Mancini, U. Pallini, B. Patelli, R. Sciaky, G. K. Suchowsky and F. Tani, Experientia, 2 2 , 468 ( 1 9 6 6 ) . L. J. Chinn, J. Med. Chem., 2, 602 ( 1 9 6 6 ) . A. G. Ruhmann and D. L. Berliner, Endocrinology, 76, 916 (1965).
10.
D. L. Berliner and A.
G.
Ruhmann, Endocrinology, 7 8 , 373
(1966).
11.
12.
W. F. Ganong, E. G. Biglieri and P. J. Mulrow, "Recent Progress in Hormone Research", V o l . 22, G . Pincus, Ed. , Academic Press, New York, N. Y., 1966, p. 381. G. W. G. Sharp and A. Leaf, "Recent Progress in Hormone Research", V o l . 22, G. Pincus, Ed. , Academic Press, New York, N. Y. 1966, p. 431.
Chap. 20 13. 14. 15. 16. 17.
18. 19. 20. 21.
22. 23. 24. 25. 26.
27. 28. 29.
30. 31. 32. 33.
Steroid Hormones
D i a s s i and Lerner
21 5 -
Cekan, M. Seda, J. Mikulaskova and K. S y h o r a , S t e r o i d s , 8, 205 ( 1 9 6 6 ) . R. E. C o u n s e l l , P. D. K l i m s t r a , R. L. E l t o n and E. F. N u t t i n g , J. Med. Chem., 9, 689 ( 1 9 6 6 ) . R. L. E l t o n , P. D. K l i m s t r a , F. B. C o u l t o n , Proc. SOC. Exp. B i o l . Med., 121, 1194 ( 1 9 6 6 ) . R. L. E l t o n , R. E. C o u n s e l l , P. D. K l i m s t r a and E. F. N u t t i n g , E x p e r i e n t i a , 2 2 , 437 ( 1 9 6 6 ) . R. A. Edgren, D. L. P e t e r s o n , R. C. Jones, G. L. Nagra, H. Smith and G. A. Hughes, " R e c e n t P r o g r e s s i n Hormone R e s e a r c h " , G. P i n c u s , Ed., Academic P r e s s , New York, N. Y., V o l . 2 2 , 1 9 6 6 , p. 305. R. A. Edgren, D. L. P e t e r s o n and R. C. Jones, I n t e r n . J. of F e r t i l i t y , ll, 389 ( 1 9 6 6 ) . R. B. G r e e n b l a t t , E. C. J u n g c k , R. A. P u e b l a and M. C. Ward, C l i n i c a l Pharm. and T h e r a p e u . , 1, 490 ( 1 9 6 6 ) . M. Roland, I n t e r n . J. of F e r t i l i t y , 2, 4 0 1 ( 1 9 6 6 ) . H. C. O'Roark, F. R. Lock, J. H. Smith-Foushee and R. L. B u r t , I n t e r n , J. of F e r t i l i t y , 11,405 ( 1 9 6 6 ) . G. H. Douglas, G. C. Buzby, J r . , C. R. Walk and H. S m i t h , T e t r a h e d r o n , 2 2 , 1019 ( 1 9 6 6 ) . G. A. Hughes, T. Y. J e n and H. S m i t h , S t e r o i d s , 8, 947 (1966). 2. Cekan and B. P e l c , S t e r o i d s , 8 , 209 ( 1 9 6 6 ) . E. Chang and V. K. J a i n , J. Med. C h e m . 2, 433 ( 1 9 6 6 ) . F. J. S a u n d e r s , P r o c . SOC. Exp. B i o l . Med., 1 2 3 , 303 (1966 1. R. V i t a l i , R. G a r d i , G. F a l c o n i and A. E r c o l i , S t e r o i d s , 8 , 528 ( 1 9 6 6 ) . A. Arnold and G. 0. P o t t s , Acta E n d o c r i n . , 52, 489 (1966). E. S h a p i r o , L. Weber, E. P. O l i v e t o , H. L. Herzog, R. N e r i , S. T o l k s d o r f , M. Tanabe and D. F. C r o w e , S t e r o a 8, 4 6 1 ( 1 9 6 6 ) . R. E. C o u n s e l l , G. W. A d e l s t e i n . P. D. K l i m s t r a and B. Smith, J. Med. C h e m . , 9, 685 ( 1 9 6 6 ) . P. D. K l i m s t r a , E. F. N u t t i n g and R. E. C o u n s e l l , J. Med. Chem., 9, 693 ( 1 9 6 6 ) . P. D. K l i m s t r a , R. Zigman and R. E. C o u n s e l l , 57. Med. Chem., 2, 924 ( 1 9 6 6 ) . H. L. Kruskemper and G. N o e l l , S t e r o i d s , 8, 1 3 ( 1 9 6 6 ) . Z.
Sect. I V
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34.
-
Metabolic & E n d o c r i n e
Heinzelman., Ed.
R. I. Dorfman and F. A. Kin4 Acta Endocrinologica,
52,
619 ( 1 9 6 6 ) . 35. 36. 37.
E. Kendle, D. K. Vallance and B. H. Vickery, Acta Endocrinologica, 5 3 , 443 ( 1 9 6 6 ) . G. C. Buzby, Jr., E. Capaldi, G. H. Douglas, et.al., J. Med. Chem., 9, 338 ( 1 9 6 6 ) . 0. Engelfried, H. Gibian, F. Neumann, K. Prezewowsky, G . Schulz and R. Wiechert, Arzneimittelforschung, 11, J. P. Bennett, K.
1518 ( 1 9 6 6 ) . 38. 39. 40.
L. M. Helm, Endocrinology, 7 8 , 1130 ( 1 9 6 6 ) . R. A. Edgren, Proc. SOC. Exp. Biol. Med., 123, 788 (1966). G. Bialy, A. P. Merrill and G. Pincus, Endocrinology, 7 9 ,
41.
125 ( 1 9 6 6 ) . U. Kerb, G. Schulz, P. Hocks, R. Weichert, A. Furlenmeier,
A. Furst, A. Langemann and G. Waldvogel, Helv. Chim. Act+ 49, 1601 ( 1 9 6 6 ) .
43.
I. T. Harrison, J. B. Siddall and J. H. Fried, Tetrahedm Letters, 3457 (1966) P. Hocks and R. Weichert, Tetrahedron Letters, 2987,
44.
H. Hoffmeister and H. F. Grutzmacher, Tetrahedron Letters,
42.
.
(1966). 4017 ( 1 9 6 6 ) .
49.
F. Hampshire and D. H. S. Horn, Chem. Corn. 37, 1966. D. H. S. Horn, E. J. Middleton and J. A. Wunderlick, Chem. Comm. 339 ( 1 9 6 6 ) . J. N. Kaplanis, M. J. ThompSOn, R. T. Yamamoto, W. E. Robbins and S. J. Louloudes, Steroids, 8, 605 (1966). K. Nakanishi, M. Koreeda, S. Sasaki, M. L. Chang and H. Y. Hau, Chem. Comm. 915 ( 1 9 6 6 ) . M. N. Galbraith and D. H. S. Horn, Chem. Comm., 905
50.
H.
45. 46. 47. 48.
(1966 1.
Schildnecht, R. Siewerdt, U. Maschwitz, Angew. Chemie, 5, 421 ( 1 9 6 6 ) .
217
Chapter 21. Non-steroidal Antiinflammatory Agents T. Y. Shen, Merck Sharp & Dohme Research Laboratories Divison of Merck & Co., Inc., Rahway, New Jersey Introduction - Interest in the search for new antiinflammatory drugs has continued with growing emphasis. During the past year more than one hundred groups of new compounds have been disclosed in the patent literature as potential antiinflammatory agents. The prospect of finding a better drug, possibly with a novel mode of action, is further enhanced by the intensive clinical and pharmacological efforts to unravel the etiology and pathogenesis of rheumatic di~n increasing appreciation of various immunological factors seases. involved in many connective tissue diseases2 has opened a new dimension to medicinal chemists. A wealth of background materials are to be found in two comprehensive monographs3y4 and several review artiCurrent clinical and biological reports are conveniently cles. 5 ,6 , abstracted in an NlH publication8, freely available to qualified investigators in this field. Etiology and Pathogenesis of Rheumatic Diseases - The detection of various infectious agents, e.g. PPL.09 and diphtheroidslO, in the synovial joints of some rheumatic patients continues to suggest that chronic symptoms may be the result of a primary infection with immunologically induced secondary manifestations. Following an acute inflammatory response the pathogenesis is initiated by the presence of an antigenic material, such as denatured y-globulin or other autoantigensll, the formation of which may involve sulfhydryl exchange reactions. An insoluble immuno complex is then formed with an antibody like rheumatoid factor, possibly with the participation of complement. The antirheumatic activity of sulfhydryl compounds, e.g penicillamine (I), may be attributable to its ability to dissociate
I
or inactivate the immuno macro globulins at this stage. The ensuing chemotaxis and phagocytosis processes have also been investigated in detail. The former is inhibited by hydrocortisone and chloroquine in vitro13, and the occurrence of extensive phagocytosis in synovial joints is evidenced by the observation of "inclusion bodiesTTinside polymorphonuclear leukocytes. l4 An outcome of phagocytosis is the release of various lysosomal proteins and enzymes15, which are capable of producing local inflammation, tissue erosion,
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protein denaturation and the generation of autoantigens, and thus completing a self-perpetuating cycle of pathogenesis. Test Methods - As a model manifesting both an acute inflammatory response and disseminated secondary lesions, the adjuvant arthritis assay in rats has become widely accepted in many laboratories. The effect of various known agents on such parameters as the decrease in foot volume, the restoration of body-weight loss, the reduction of plasma "inflammation units"16, and the change in erythrocyte sedimentation rate has been described. 179 189 l9 The relative potency of known drugs was estimated by Glenn20 as indomethacin (11), 81, hydro-
c1 I1
cortisone acetate 6, flufenamic acid (111) 1.6, indoxole (IV) 1.1,
phenylbutazone 1 and ibufenac ( V ) 0.5. With certain immune suppressive agents, Newbould21 observed that the gradual development of secondary lesions (polyarthritis) is inhibited by a three-dose treatment started just before the challenge with Freund's adjuvant. The procedure of inducing inflammation in canine joints with microcrystalline sodium urate h a s been modified and extended to man. 2 2 , 23 When needed, this assay provides another animal species for preclinical evaluation of new drugs. With the availability of new non-steroidal agents as reference compounds, the development of new -in vitro assays as potential primary screens has been much facilitated. According to M i ~ u s h i m a ~ ~ , the thermal denaturation of protein can be inhibited by a number of antiinflammatory compounds with an order of activity roughly in agreement with their in viva potency. As a sim le model to study the stabilization of lysosomal membrane, Brown2 has described a new I !
Chap. 21
Antiinflammatory
Shen
219 -
protocol based on heat-induced hemolysis of canine erythrocytes. The interaction of antiinflammatory acids with the lysyl&-amino group in serum albumin or histidine decarboxylase, in competition with pyridoxal phosphate, was suggested by WhitehouseZ6 as a mode of action for these agents and adoptable as a preliminary assay. It is interesting to note that the lysyl €-amino group has also been implicated in the cross-linking of fibrinsz7 and collagen (after oxidation to aldehyde).28 Alterations in the reactivity and serum level of free sulfhydryl groups have previously been related to connective tissue diseases. An in vitro assay measuring the acceleration of disulfide interchange between serum sulfhydryl groups and 5,5'-dithiobis (2-nitrobenzoic acid) (DTNB, Ellman's reagent VI) by non-steroidal a ents was recently described." The increased rate may be indicative of free sulfhydryl groups uncovered by antiinflammatory agents through an induced conformational change of the protein molecule. However, Hichens30 observed that antiinflammatory compounds can block the binding site of DTNB, which has a configuration not unlike several antiinflammatory aryl acids. Thus, the acceleration may be caused by an increase of unbound DTNB conNO, centration instead. Studies on G the inhibition of various tissue VI proteases by known drugs have been extended. 31 Several antiinflammatory acids have also shown fibrinolytic activity -in vitro at relatively high concentrations. 32 This is coincidental with a recent clinical note suggesting the application of fibrinolytic agents in rheumatoid arthritis.33
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-
So far, no single in vitro assay has been generally accepted as the most promising preliminary screening. Many antirheumatic drugs have shown activity in a variety of the in vitro assays mentioned above. Obviously the spectrum of a compound and not the activity in any single assay should be emphasized. At the present time, the optimal biochemical profile of an ideal agent remains shrouded in the unknown.
Indomethacin and Analogs - Among several isosteric modifications of indomethacin studied at M e r ~ k ~an~ indene , isoster, 77cis77-l-p-chlorobenzyl~denyl-5-methoxy-2-methyl-3-indenylacet~cacid (VII ), was found to be half as active as indomethacin. The corresponding 77transr7isomer was only one-tenth as active. The structure-activity relationship of N1-aroyl and N -aralkyl indole acetic acids is generally parallel to that of inaene isosters, indicative of a similar mode of action. Based on X-ray diffraction data, the nonplanar configuratim of the &-isomer was suggested as the preferred conformation of
-
2 20 -
Sect. IV
- Metabolic & Endocrine
Heinzelman, Ed.
indomethacin (11) in vivo. The possible modes of action of indomethacin remain to be a subject of active interest. As a reference compound it has been found to be active in most of the in vitro and in-vivo assays mentioned above. While none of these can be considered as the primary mode of action, certainly several are contributory. An earlier report35 of kallikrein inhibition was not confirmed.36 The suggestion37 that the antiinflammatory activity of indornethacin may be due to the displacement of tissue-bound corticosteroid has also been disputed. 38 The distribution and metabolism of indornethacin in various species have been reported in detail39, and a number of long-term clinical studies have been p ~ b l i s h e d . ~ O - ~ ~
--
--
Aryl acetic Acids - Of several aryl acetic acids described in the last report, no significant developments have been noted regarding Fbufenac and namoxyrate. Detailed pharmacology and toxicity data on naphthypraide AVIII )44 and E-n-butoxyphenylacethydroxaic acid (CP 1044 53, Ix)45, 6 have been puGlished. The antiinflammatory potency
CH,
I
VIII
IX
of the latter is comparable to phenylbutazone and is at least partly
attributable to its effects on the adrenals. The corresponding amids has analgesic activity only, and the free acid is completely inactive, Available animal data indicated that several substituted phenyl aliphatic acids possess a high degree of antiinflammatory activity, greater than or comparable to that of indomethacin. In the carrageenin edema assay the ED% of ( + ) 3-chloro-4-cyclohexyl-a-methylphenylphenylacetic acid (X) is ca. 0.3 mg/kg.47, Being the most potent compound reported so far. 4~iphenylyl-3-hydroxybutyricacid (XI) has an ED50 of 14 mg/kg. in the edema assay and a otency of six times Another analog, pphenyibutazone in the U.V. erythema assay.45 anilinophenylacetic acid (XII)49 also showed a high degree of-
Chap. 21
Antiinflammatory
Shen
221 -
a c t i v i t y i n b o t h edema and a d j u v a n t a r t h r i t i s a s s a y s . The o r t h o aniS u b s t i t u t e d 3l i n o a n a l o g s (see fenamates below) are l e s s a c t i v e . p h e n o t h i a z i n y l a c e t i c a c i d s s 0 , o-benzamidophenoxy and o-benzamidophenyl acetic acids51 have also-been claimed. A s w i t h indomethacin a n a l o g s , t h e -i n vivo b i o l o g i c a l a c t i v i t y of s e v e r a l a - m e t h y l p h e n y l a c e t i c a c i d s i s i n v a r i a b l y a s s o c i a t e d w i t h t h e d e x t r o r o t a t o r y isomer of t h e s i n i s t e r a b s o l u t e conf i g ~ r a t i o n . ~ ~ Thus t h e s t e r e o - s p e c i f i c i t y of t h e a-carbon atom of t h e s e a n t i - i n flammatory a g e n t s appears t o b e i d e n t i c a l w i t h t h a t of p l a n t growth hormones.
Fenamates - The a n t i r h e u m a t i c e f f i c a c y of b o t h mefenamic a c i d and f l u f e n a m i c a c i d (111) have been demonstrated i n t h e c l i n i c . 5 2 , 5 3 The equipotency dose w a s e s t i m a t e d as a s p i r i n 2.4 g. mefenamic acid1.7g., f l u f e n a m i c a c i d 0.67 g. and phenylbutazone 0.33 g., r a t h e r a t v a r iance w i t h t h e i r a c t i v i t i e s i n a n i m a l s . No o u t s t a n d i n g d i f f e r e n c e s between t h e s i d e - e f f e c t s of t h e f o u r d r u g s w e r e r e p o r t e d i n t h i s study. C l i n i c a l d a t a on t h e more p o t e n t congener, meclofenamic a c i d ( C I 583, X I I I ) h a s not been p u b l i s h e d . 0
I n t e r e s t i n c l o s e a n a l o g s of f e n amates i s i l l u s t r a t e d by 8-trifluoromethyl phenothiazine-l-carb o x y l i c a c i d ( X I V ) 5 4 ( a n S-bridged NH and t h e a c e t i c a c i d homoHeterocyclic analogs are exem l i f i e d by s e v e r a l p y r i m i d i n e 1 @ c3: ( X V I g 6 and p y r i d i n e (XVI)57 i s o X I I1 sters. ReDlacement of t h e c a r b o x y l group by a t e t r a ~ o l er e~s u ~ l t e d i n a s l i g h t l y l e s s a c t i v e b u t poss i b l y lezs t o x i c analog. I t i s noteworthy t h a t t h e o p t i m a l a c t i v i t y
,E, XIV
0
I
Sect. IV - Metabolic & Endocrine
222 -
Heinzelman, Ed.
enhancing groups of these analogs apparently are considered to be identical with those in fenamates, i.e., 2,6-diC1-3-Me, 3-CF3 and 2 , 3-diMe, originally selected by the Parke-Davis group.
--
-
In the chemical study of indoxole (XVII)59 and its analogs the minimum structure requirement for significant activity was defined as 2,3-diphenyl indole. The potency enhancing effect of two 5 G H CH3 3 p-methoxy groups was specific and additive. Substitutions at C 5 of the indole ring (a sensitive position in the indomethacin series) by XVII C1, F and CH had little influence 3 on the activity, whereas N1-alkylation and acylation were detrimental. The highly conjugated system has strong U.V. absorptions at ca. 250 and 310 m p suggesting that the two anisyl groups, like thearyl groups in fenamates and phenylbutazone, are not coplanar. Biological activity in animals was related to the log of the average serum level which is largely determined by the solubilizing vehicles used in formulation.20,60 Indoxole was modestly active in crystal-induced synovitis in man at 2.4 g/day.61 Indoxole
’
-
Sulfhydryl Compounds - The anti-rheumatic activity of penicillamine (I) has been attributed by Lorber12 to its ability to dissociate abnormal macroglobulin and to restore serum sulfhydryl levels in vivo, either through sulfhydryl-disulfide interchange or chelation of divalent metal ions like copper which catalyze the oxidation of sulfhydryl groups. Penicillamine, cysteine and other thiol compounds are ca able of solubilizing collagens in vitro62 as well as vivo.65 Inhibition of kallikrein and foot-edema in guinea pigs by these compounds has also been noted.64
--
-
Immune Suppressive Agents - Satisfactory clinical results have been obtained in the treatment of rheumatoid arthritis with an immune suppressive agent cycl~phosphamide~~, but wider application must await the availability of a safer and less toxic agent. Following the discovery of a novel antipolyarthritic agent 47,776 (XVIII), was I.C.I. 43,82317, a thiophene derivative, I . C . I . described as a new immune suppressive agent capable of inhibiting HO the development of polyarthritic lesions, antibody response and other autoimmune syndromes in rats. The inhibition was attributed to interF ference with generation of high XVIII energy phosphate esters necessary for protein and nucleic acid synthesis. These potent cytotoxic agents are valuable laboratory tools
pJ3
Chap. 21
Shen
Antiinflammatory
223
but of limited clinical applications.
-
Miscellaneous Two novel agents reported to possess antiinflammatory, antipyretic and analgesic activities nearly comparable to phenylbutazone are N,N-Di(m-aminopheny1)butyl-ethylmalonamide (Gy-97, X I X ) 6 6 and 1-(4-~hlorophenyl)-4-[2-[ 3-(2-pyridyl )acryloxy)ethyl] piperazine (DA 1529 XX).67 Gy-97 also has anti-histaminic and anti-
0
XIX
xx
anaphylactic properties, whereas DA 1529 possessesmild CNS depressant properties. The biochemical properties of chloroquine and related antimalarials have been examined further. In addition to its inhibition of the biosynthesis of sulfated mucopolysaccharides, chloroquine inhibits irreversibly an autolytic enzyme from bovine cartilage and a ~ hydrocortisone, it inhibits rat skin collagenase (at 10 r r ~ M ) . ~Like chemotaxis of leukocytes and, to a lesser extent, the phagocytosis process.13 It also stabilizes lysosomal membranes in vitro. Potential “anti-degenerative” activity is clearly suggested by these properties, but unfortunately the well-known retinopathic effect is further complicated by a delayed symptom.69
--
Proceedings of an international conference on dimethylsulfoxide have been summarized.70 The FDA restriction of DMSO has been modified to allow limited investigations of this unique agent. One of its metabolites, the crystalline dimethylsulfone, also possesses a weak antiinflammatory activity.71 On the other hand the phenyl derivatives, benzyl methyl sulfones and ~ u l f o x i d e s ~have ~ , been found to be more potent but short acting anti-edema and analgesic agents
.
Sect. I V
224
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Heinzelman, Ed.
References
f 1) D. Hamerman. Amer. J. Med.. -40. 1 (1966). -, A. J. B o l l e t , P o s t g r a d u a t e Med., 391 ( O c t . 1966). i2j (3) The Inflammatory P r o c e s s , B. W. Zweifach, L . Grant and R . T. McCluskey, Eds., Academic P r e s s , N e w York, 1965. J . L. H o l l a n d e r , Ed., A r t h r i t i s and A l l i e d C o n d i t i o n s , Lea (4) and F e b i g e r , P h i l a d e l p h i a , 1966. C. A. Winter i n E. J u c k e r , Ed., P r o g r e s s i n Drug Research, (5) Vol. 10, B i r k h a u s e r Verlag, B a s e l - S t u t t g a r t , 1966, i n p r e s s . R. Domenjoz, Advances i n Pharmacology,& 143 ( 1 9 6 6 ) . (6) T. Y. Shen, Topics i n Med. Chem., V o l . 1, 1967 i n p r e s s . (7) (8) A r t h r i t i s and Rheumatic Diseases A b s t r a c t s , N a t i o n a l I n s t . of A r t h r i t i s and Metabolic Diseases, N a t i o n a l I n s t i t u t e of H e a l t h , Bethesda, Maryland, 20014. (3) E. V. B a r n e t t , P. B a l d u z z i , J. H. Vaughan and H. R. Morgan, A r t h r i t i s R h e u m . , a 720 ( 1 9 6 6 ) . (10) J. J. R. D u t h i e , S . M. S t e w a r t , W. R. M. Alexander and R. E. Dayhoff, The L a n c e t , 142 ( J a n . 21, 1967). (11) J. L. H o l l a n d e r , H. H. Fudenberg, A. J. Rawson, N. M. Abelson and T. P. T o r r a l b a , A r t h r i t i s and R h e u m a t i s m , A 675 (1966). A. Lorber, N a t u r e , 1235 (1966). (12) P. A. Ward, J . E x p t l . Med., 209 ( 1 9 6 6 ) . (13) J . M. R i d d l e , G. M. Bluhm and M. I. B a r n h a r t , J. R e t i c u l o e n (14) d o t h e l i a l . SOC., 420 (1965). (15) A. Janoff and S. S c h a e f e r , N a t u r e , 144 ( 1 9 6 7 ) ; S. Wasi, R. K. Murray, D. R . L. Macmovine and H. 2. Movat., B r i t . J. E x p t l . 411 ( 1 9 6 6 ) . Pathol., E. M. Glenn and W. M. Kooyers, L i f e S c i . , 619 ( 1 9 6 6 ) . (16) B. B. Newbould, B r i t . J. Pharmacol., 632 ( 1 9 6 5 ) . (17) C. A. Winter andsitRheum., 394 ( 1 9 6 6 ) . (18) (19) S. S. P i l l i e r s , M. L. G r a e m e , B. B. S i g g , G. Chinea and C. Colombo, L i f e S c i . , 1057 (1966). E. Myles Glenn, B. J . Bowman, W. Kooyers, T. Koslowske and M. (20) L. Myers, J . Pharmacol. Exptl. Therap., lz, 157 (1967). T. J. F r a n k l i n , B. B. Newbould, D. M. O'Mant, A. I . S c o t t , (21) G. J . S t a c e y and G. E. Davies, N a t u r e , 638 ( 1 9 6 6 ) . D. J. M c C a r t y , J r . , P. Phelps and J. Pyenson, J . Exp. Med., (22) 1 3 , 99 (1966). A. D. S t e e l e and D. J. M c C a r t y , J r . , A r t h r i t i s Rheum.,& (23) 430, ( 1 9 6 6 ) . Y. Mizushima and H. S u z u k i , Arch. i n t . Pharmacodyn., a 7 , 115 (24) (1965). J . H. Brown, H. K. Mackey and D. A. R i g g i l o , A b s t r a c t s of (25) P a p e r s 152nd Am. Chem. SOC. Meeting, September, 1966, N e w York, N e w York, P-13. (26) I. F. Skidmore and M. W. Whitehouse, Biochem. Pharmacol., 1965 (1966). L. Lorand, H. H. Ong, B. L i p i n 6 k i N. G. Rule, J. Downey and (27) A. J a c o b s e n , Biochem. Biophys. R e s . Comm., ? ,& , 629 (1966). I
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( 2 8 ) P. Bornstein and K. A. Piez, Biochem.,A 3460 ( 1 9 6 6 ) . ( 2 9 ) D. A. Gerber, N. Cohen and R. Giustra, Biochem. Pharmacol., 115 (1967). ( 3 0 ) M. Hichens, Unpublished observations. ( 3 1 ) I. F. Skidmore and M. W. Whitehouse, J. Pharm. Pharmacol., & 558 ( 1 9 6 6 ) . ( 3 2 ) R. J. Gryglewski and T. A. Gryglewska, Biochem. Pharmacol., 15, 1171 ( 1 9 6 6 ) ; 2. Roubal and 0. Nemecek, J. Med. Chem.,jZ, 840 (1966). ( 3 3 ) G. R. Fearnley, R. Chakrabarti and J. F. Evans, Lancet, 757 (Oct. 1 9 6 6 ) . ( 3 4 ) T. Y. Shen, R. L. Ellis, B. E. Witzel and A. R. Matzuk, Abstr.
of Papers, 152nd Meeting, Am. Chem. SOC., New York, New York, Sept. 1966, 3P. ( 3 5 ) M. N-I Walters and D. A. Willoughby, J. Path. Bact., 9 2 , 641 (1965). ( 3 6 ) G. E. Davies, G. Holman, T. P. Johnston and J. S. Lowe, Brit. J. Pharmacol. Chemother., Za, 212 ( 1 9 6 6 ) . ( 3 7 ) B. B. Brodie, G. J. Cosmides and D. P. Rall, Sci., 1547 (1965). i 3 8 ) 'C. A. Winter, E. A. Risley and R. H. Silber, Fed. Proc., 620 11967). ( 3 9 ) H. B. Hucker, A. G. Zacchei, S. V. Cox, D. A. Brodie and N. H. R. Cantwell, J. Pharmacol. Exptl. Therap., 237 ( 1 9 6 6 ) . ( 4 0 ) N. 0. Rothermich, J. Amer. Med. ASSOC., 1 2 3 , 1102 ( 1 9 6 6 ) . ( 4 1 ) Council on Drugs, J. Amer. Med. ASSOC., 651 ( 1 9 6 6 ) . ( 4 2 ) The Cooperating Clinics Committee of the Amer. Rheumatism ASSOC., New York, Clinical Pharmacol. Therap.,,&, 11 (1967). ( 4 3 ) C. J. Smyth, Arthritis Rheum.,,& 921 ( 1 9 6 5 ) ; P. J. Bilka, Arthritis Rheum., &, 431 (1965). ( 4 4 ) E. Marazzi-Uberti and C. Turba, Arch. Int. Pharmacodyn., 378 (1966). ( 4 5 ) R. Roncucci, M. J. Simon, G. Lambelin, N. P. Buu-Hoi and J. Thirianx, Biochem. Pharmacol., 1563 ( 1 9 6 6 ) . ( 4 6 ) N. P. Buu-Hoi, G. Lambelin, C. Gillet, C. Lepoivre, J. Thiriaux and G. Mees, Nature, 211, 752 ( 1 9 6 6 ) ; G. Lambelin, N. P.
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Buu-Hoi, G. Mees, J. Thiriaux and M. Huriaux, Med. Pharmacol. Exp., J& 545 (1966). ( 4 7 ) T. Y. Shen, C. P. Dorn, W. V. Ruyle, B. E. Witzel, C. H. Shunk, A. R. Matzuk, H. Schwam, R. L. Bugianesi, L. Bock, H. M. Lewis, G. E. Arth, and A. A. Patchett, Abstr. of Papers, Am. Chem. SOC. 2nd Middle Atlantic Regional Meeting, February, 1967, New York, New Yolk, p. 46; C. A. Winter, unpublished results. ( 4 8 ) British Drug Houses, South Afr. P. 65/3510 ( 1 9 6 6 ) . ( 4 9 ) Rhone-Poulenc, South Afr. P. 65/6358. ( 5 0 ) Rhone-Poulenc, South Afr. P. 65/5718. ( 5 1 ) Smith and Naphew, French P. 1 , 4 4 6 , 6 2 2 (1965). ( 5 2 ) Today's Drugs, Brit. Med. J., 1506. ( 5 3 ) D. E. Barnardo, H. L. F. Currey, R. M. Mason, W. R. Pox and (Aug., 1966). M. Weatherall, Brit. Med. J.,
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( 5 4 ) B. M. S u t t o n and J. H. B i r n i e , J . Med. Chem., 835 ( 1 9 6 6 ) ; Smith, K l i n e and French, South Africa P a t . 65/6180 ( 1 9 6 6 ) . ( 5 5 ) Geigy, Belg. P a t . 679, 315 (1966). ( 5 6 ) Bristol-Myers, U.S. P a t . 3/254,086, 3,254,087 ( 1 9 6 6 ) . ( 5 7 ) S c h e r i c o , Ltd., Belg. P a t . 679, 271 (1966). ( 5 8 ) B r i s t o l - M y e r s , Belg. P a t . 679,245 (1966). ( 5 9 ) J. Szmuszkovicz, E. M. Glenn, R. V. Heinzelman, J. B. H e s t e r , Jr., and G. A. Youngdale, J. Med. C h e m . , A 527 ( 1 9 6 6 ) . ( 6 0 ) D. G. Kaiser, E. M. Glenn, R. H. Johnson and R . L. J o h n s t o n , J. Pharmacol. E x p t l . Therap., 174 ( 1 9 6 7 ) . 39 ( 6 1 ) A. D. S t e e l e and D. J. M c C a r t y , Ann. Rheum. D i s . , (1967). 434 (1966). ( 6 2 ) M. E. N i m m i , Biochem. Biophys. R e s . Comm., ( 6 3 ) E. D. H a r r i s , Jr., and A. Sjoerdsma, The L a n c e t , 996 (Nov. 5 , 1 9 6 6 ) ; E. D. H a r r i s , Jr., I. Jaffee and A. Sjoerdsma, Arth. and Rheum., A 509 (1966). ( 6 4 ) ' G. E. Davies and J. S . Lowe, B r i t . J. Pharmacol. Chemother., 107 (1966). ( 6 5 ) Med. World N e w s , 31 (1967). ( 6 6 ) P. G6rdg and L. Szporny, A r z n e i m i t t e l - F o r s c h u n g , fi 1 2 1 1 (1966). ( 6 7 ) E. Marazzi-Uberti, C. Turba and C. B i a n c h i , J. Pharma. S c i . , % 1105 (1966). ( 6 8 ) F. K. Cowey and M. W. Whitehouse, Biochem. Pharmacol., 1071 (1966). ( 6 9 ) R. P. Burns, New England J. Med., 3,693 ( 1 9 6 6 ) ; B r i t i s h Med. J., 254 (Feb. 1967). (7o)C. A. Leake, S c i e n c e , J5& 1646 (1966). ( 7 1 ) C. A. Winter, B. E. Witzel and T. Y. Shen, Unpublished observations. ( 7 2 ) Merck,Neth. P a t . 66,07144 ( 1 9 6 6 ) .
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Editor:
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Section V Topics in Biology I.I.A. Tabachnick,Schering Corporation, Bloomfield, New Jersey
Chapter 2 2 . Molecular Aspects of Drug-Receptor Interactions. Barry M. Bloom, Chas. Pfizer & Co., Inc. , Groton, Connecticut "Membrane biochemistry occupies a central position in modern biology, second in importance, perhaps, only to biochemical genetics. Replication and organization are the significant differences between living and nonliving catalytic systems, and cellular org nization is a function of membranes." Edward D. Korn
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Membrane Biology There is a growing realization among drug research scientists that many receptor systems of major interest are located in the plasma membranes of cells. Sites responsive to acetylcholine, epinephrine, histamine, serotonin, peptide hormones such as insulin and oxytocin, and the plasma kinins are almost certainly among this group. These receptor systems usually remain fully responsive only as long as the structural integrity of their highly architectured residence is maintained, and therein lies the main stumbling block to their direct study along lines successful with enzyme systems. Nevertheless, the present decade has witnessed remarkable progress in the isolation and analysis of various plasma membrane systems, and new knowledge has been amassed at an impressive pace. It seemed, therefore, particularly timely this year to review those aspects of the field of membrane biochemistry and ultrastructure that appear most pertinent to the study of drug receptor systems.
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The Repeating Unit Concept of Biological Membranes An important concept has emerged in recent months that deviates importantly from earlier views on the nature of biological membrane systems. The theory, as put forward by Benson* and by Green and his colleague^^'^, suegests that biological membranes are vesicular or tubular systems built up of nesting, lipoprotein repeating units one layer thick. This viewpoint, along with a considerable amount of compelling evidence that supports it, has been brilliantly summarized in several papers. One chapter in a new book by Green and Goldberger' provides an outstanding introduction to the field of membrane biology, viewed from this new perspective. Judging from the evidence at hand, it would appear that the repeating unit visualization seems destined to replace the classical Danielli-Davson model of plasma membrane ultrastructure that has dominated thinking on the subject ever since it was first proposed in 1935. In the classical model, as well as its more contemporary variant, the Robertson unit membrane hypothesis, membranes are seen to consist of a bimolecular leaflet of phospholipid sandwiched between two layers of globular protein. The nen-polar fatty acid chains of the phospholipid are oriented inward, perpendicular to the plane of the membrane system. The polar groups of the phsspholipid at the external surface of the bimolecdar leaflet are presumed to bond electrostatically to the protein, affording
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two essentially separate but continuous phases. Excellent reviews and critiques of these earlier hypotheses are a~ailablel,~. Because of the potentially great heuristic value of knowledge about membrane structure, the following three sections are devoted to a sumary of the repeating unit concept as it appears most relevant to the study of receptor systems. Mention is made of the molecular nature of the repeating units, the types of cohesive and repulsive forces that appear to be important in membrane systems, and discernible relationships between form and function. The probable mode of membrane biosynthesis is reviewed as a likely source of fundamental insights.
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Membrane Formation The formation of a biological membrane, according to the repeating unit viewpoint, begins with the geneticallycontrolled synthesis of the individual component proteins and phospholipids These interact through specific hydrophobic bond formation to afford one repeating unit or macromolecular lipoprotein complex. It assumes the conformation thermodynamically most stable under physiological conditions. The repeating units then aggregate in two dimensions with similar (or different but compatible) particles to form the membrane continuum. This latter process occurs spontaneously in the proper environment and requires no "informational" molecules. The resulting structure is dynamic in character. A constant input of metabolic energy is required to maintain its structural integrity, and it undergoes conformational changes quite readily under the influence of various stimuli.
In contrast to classical membrane theory, the repeating unit concept is clearly compatible with the fundamentals of molecular genetics, in that organization and function are controlled through the mechanisms of protein synthesis. Genetically-determined amino acid sequences are seen to afford protein tertiary structures characterized by a hydrophobic interior that could facilitate specific associations with the lipid chains of particular phospholipid components. It is an established fact that the phospholipids of mammalian tissue are highly specific as to their fatty acid content (another point of genetic control), so that one would anticipate a high order of influence for the protein amino acid sequence on which lipids are mo'st stably bound to them, as well as where and how they are bound. This, in turn, would largely determine,the tertiary strncture of the protein-phospholipid macromolecular complex, including such key features as the distribution of polar functionality on the membrane surface. The phospholipid component appears to determine the preferred mode of combination of repeating units with one another. Lipid-free particles polymerize to three-dimensional aggregates, which are essentially bulk phases devoid of enzymatic activity. Reintroduction of phospholipid restricts the repeating units to "side to side" interactions involving predominantly hydrophobic protein-to-protein bonds. This type of interaction affords an enzymatically-active membrane continuum. It has been concluded, therefore, that the essentiality of phospholipid for normal enzymatic function in such systems reflects Lheir ability to "direct" membrane formation rather than any specific chemical effect exerted directly on the enzyme5.
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Repeating Unit Composition The repeating units that have been detected in various types of cell membranes appear to be made up of socalled base pieces, which are the sub-units essential to membrane formation, and detachable portions (headpieces and stalks) which contain enzymatic activity, but are not essential to the membrane continuum per se. The headpiece and stalk can be detached through procedures such as sonication or detergent action, without disruption of the membrane. The repeating units themselves can also be disassociated by detergent action. Upon removal of the disassociating influence, the units will spontaneously reaggregate to form vesicular membranes. Going one step further, solvent extraction of lipid from repeating units removes their ability to form membranes, but this can be restored by reintroduction of the extracted lipid. The tendency to form membranes would, therefore, seem to be an expression of the intrinsic chemical properties of these lipoprotein repeating units. The molecular weight of repeating units appears to range from 50,000 to over a million. The particles from inner mitochondria1 Eembrane, for example, have a size (MW about 1.3 million; diameter about 150A) that corresponds to about 600 phospholipid molecules (MW = 800) and 30 protein molecules (MW = 25,000). On the assumption that the base piece constitutes about 40% of the entire repeating unit, Green and Goldberger6 estimate that it would contain about six each of structural and catalytic proteins, along with about 240 phospholipid molecules. Membranes commonly appear to possess structural and catalytic proteins in about a 1 ; l ratio.
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Membrane Function The primary functional properties manifested by plasma membranes include a selective permeability toward ions and molecules, the ability to translocate such species at the expense of metabolic energy, and highly specialized enzymatic activities characteristic of the function of the parent tissue. They also often contain glycolytic enzymes to help meet energy needs. Determining the location of the enzymatic activity responsible for any of these functions is a complicated problem in itself. Most systems are characterized by a multiplicity of membranes, single membranes being the exception. Location thus becomes a question of which membrane, which species of repeating unit, and which sector of the repeating unit is involved. Repeating units of varying composition can apparently be sufficiently complimentary to form a given membrane, and enzymatic properties are often parcelled out in blocs to different species of repeating units. For example, it is felt that the inner membrane of the mitochondrion may be comprised of as many as ten species of elementary particles, each chemically and enzymatically different, with electron transfer involving a set of four of these. It is intriguing to speculate whether this same kind of ultrastructural differentiation (different repeating units) underlies the recognized ability of a single type of smooth muscle cell, for example, to respond to stimulation by a number of different hormones and humoral substances, each in a chemically precise but different way. Hokin8 has already suggested the existence of ‘‘membranepatches of active liproprotein
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specialized to carry out various functions.” Permeability characteristics toward ions and polar molecules, which vary greatly among membranes, presumably reflect the tightness of fit among repeating units, as well as the nature of the functionality lining the potential pores or channels. Permeability modification, by metal ions for example, is attributable to their ability to change the size, shape and volume of repeating units, presumably by interacting with phospholipid anionic centers. This can induce phase transitions9 which profoundly alter the nature of the membrane. In fact, the action of metal ions can entirely transform the shape of the organelle or cell involved.
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Selected References on Membrane Biology A number of other important papers and books on membrane biology have been published recently. KavanaulO has written two provocative volumes in which he views the biological membrane as a dynamic and highly labile entity, shifting between different substructural states with different phases of function. The proceedin s of symposia on membrane biology have been reviewedll and publishedl2, 3 . The complexities of membrane phospholipids have been reviewed and their role in membrane function analyzed, espein some cially by the Hokins‘’. Wolfel’ has provided a useful review of cell membrane const u nts as they relate to transport mechanisms. Kennedy and his colleagues!!6-’2 have conducted well-designed experiments with the $-galactoside permease system in E. coli. Other noteworthy papers discuss the properties and stabilization of lysosomal membranese3 and the similar effects of phospholipase C (a phospholipid ydrolyzing enzyme) and insulin on glucose transport in isolated fat cells2 k
s5
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Two recent s t u d i e ~ ~ ~on , ~the ~ ,molecular nature of cell membrane protein offer an excellent illustration o f the power of modern instrumental techniques in this field of biology. They provide evidence that supports a model of membrane structure closely akin to the repeating unit visualization, through the use of ORD and CD coupled with refined methods o f membrane fractionation. Additional information of importance was obtained on the degree of similarity among membrane structural proteins from different types of cells, the proportion of membrane protein that seems to assume a helical conformation, and the hydro hobic nature of the membrane interior. These same two papers and others27-32 serve as excellent leading r ferences to methods of membrane isolation and fractionation. IR33 and NPIR3‘ studies on membrane fractions have been performed with less rewarding results than the ORD and CD efforts cited.
Changeaux and his colleagues35 have analyzed the amplifying properties of repeating unit membranes as they respond to ligand binding, from a viewpoint that reflects previous association with M ~ n o din~ the ~ field of regulatory enzyme mechanisms. The result is a generalized mathematical model of the so-called cooperative properties of membranes. In effect, this constitutes the first receptor theory specifically related to the new concept of membrane structure, in that it emphasizes the relationship between the conformational transitions undergone by repeating units and ligand (drug) binding. One prediction of the model i s that the concept
Chap. 22
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of "intrinsic activity" of a drug, as introduced by Arigns, is an unnecessary one. Receptor Systems The proceedings of a recent conference on adrenergic blocking drugs37 contain a wealth of material. B e l l e a ~provides ~~ a provocative stereochemical model for the adrenergic a-receptor based on the idea of catalysis of ATP cleavage to P by a-agonists, as proposed recently in the "dynamic receptor" hypothesis"j3'. Certain of the structural speculations offered are clearly influenced by his assumption that the membrane cation transport AlTase system is involved. This is unfortunate,since the primary influence of a-agonists on cation transport (rapid K+ efflux) is just the opposite of the result to be expected from stimulation of that system. The ability of norepinephrine to stimulate the rate of a different phosphate ester-hydrolyzing enzyme has recently been demonstrated in a synaptic membrane fraction from rat brain h o m ~ g e n a t e s ~ ~ . Robison, Butcher and S ~ t h e r l a n dspeculate ~~ that both a- and f3-adrenergic receptor mechanisms are related to adenyl cyclase. Criticism of this hypothesis is summarized by C0tte1-i~~. Three different laboratories have reported studies of the adrenergic a-receptor employing labeled, insurmountable antagonists of the f3-haloalkylamine type, which bind covalently to an essential component of this SY@y2 The carefully-designed experiments of Triggle and his colleagues show quite clearly that the usefulness of this type of adrenergic blocking agent for receptor "structure" studies is severely limited by their low tissue specificity. For example, uptake of H3-labeled N-(2-bromoethy~N-ethyl-N-l-naphthylmethylamine by a-receptor-containing tissue proves to be a linear function of the bath concentration of drug, even at concentrations well beyond the amount required to effect complete pharmacological blockade. It is intriguing to speculate whether this experimental approach might prove more fruitful when applied to an appropriate membrane fraction rich in receptor material. This question seems likely to receive attention as soon as the necessary isolation and purification techniques are mastered in laboratories conducting receptor research. Despite experimental limitations, these studies with p-haloalkylamine antagonists have led to certain conclusions regarding the concentration of a-receptors and the significance of "spare receptors" in rabbit aortic strips. Lewis and Miller43,44 have analyzed the same problems, using H3-phenoxybenzamine in rat seminal vesicle preparations. Both of these groups and another from Manitoba45 have offered criticism of certain of the data and conclusions from an earlier study by Dikstein and Sulman46, especially the suggestion that alkylation by Dibenamine involves a cephalin-like fraction of the a-adrenergic receptor system. Studies on isolated guinea pig vas deferens tissue47 have been interpreted as showing that trypsin can reverse an insurmountable blockade
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of adrenergic a-receptors established with a B-haloalkylamine. The authors conclude that the anionic site of the receptor is a carboxyl group derived from arginine or lysine. However, attempts to repeat these experiments elsewhere4I have served to demonstrate that the increased responsiveness of alkylated tissue toward a-agonists, observed following incubation with trypsin, also occurs with non-alkylated (untreated) tissue. Furthermore, proteolytic enzymes unrelated to trypsin in their action are also capable of reversing the blockade, suggesting that the tissue modification involved in restoring sensitivity is not directly related to the drug-receptor complex. Gillespie48,49 has employed fluorescence techniques to show that smooth muscle membrane can bind norepinephrine, and that this binding can be prevented by prior treatment with the a-adrenergic blocking agent, phenoxybenzamine
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A recent series of pharmacological studies has analyzed certain steric aspects of adrenergic drug struct~res~~,51. Biel and Lum52 and Ari&s3’ have reviewed the rapidly expanding field of j3-adrenergic receptor blocking agents, emphasizing their pharmacology and important structure-activity relationships. Pratesi, Lilla and Grana53 have analyzed a group of nuclearsubstituted N-isopropylphenethanolamines for the relationship between their properties as $-adrenergic blocking agents and their lipophilic character. A linear correlation was observed between lipophilicity(T in the Hantsch sense) and non-specific spasmolytic activity, but specific, competitive antagonist activity at $-receptors proved to be a quadratic function of rT. Wenke has done a scholarly analysis of the effects of catecholamines, their analogs, and various blocking agents on the adrenergic receptors re ulating lipid mobilization in adipose tissue. His reviews of the subject3 9 ~ 5 4 ,as well as experimental studies published recently with several colleague^^^, go far to dispel existing confusion about the nature of the adrenergic receptor mechanisms that serve to regulate lipolysis.
The relationship between an observed physiological response and the receptor event that triggers it often introduces complexities that are a source of serious confusion to those studying mechanism at the receptor level. Any knowledge that contributes to a better understanding of such relationships is worth having. The so-called cascade reaction, wherein a weak initial stimulus undergoes a series of amplification reactions to provide a strong ultimate response, has been clear1 explained, using epinephrine-induced glycogenolysis as an example$6 Visual excitation and the blood coagulation mechanism are other recognized examples of cascade processes57.
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A generalized analysis of the stimulus-response-recovery cycle and its relationship to receptors has been offered by Dikstein and Sulman58 A preliminary attempt has been made to label the muscar inic
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lines similar to the a-adrenergic receptor cholinergic receptor, studies already mentioned . H3-Dibenamine was employed, with atropine as protecting agent. Future experiments will doubtless employ the new alkylating species, N-2-chloroethyl-N-methyl-2-aminoethyl benzilate, recently described by Gill and Rang60. This compound, which is analogous in structure to benzilylcholine, is a highly specific, long-lasting antagonist which effectively inhibits the muscarinic actions of exogenous acetylcholine. Benzilylcholine and hyoscine protect against the pharmacological blockade it induces.
alo:fi
Ariens61'62 has reported finding potent anticholinergic activity among benzilylcholine analogs devoid of any cationic head (amine moiety). The concept of an interaction of a competitive antagonist with a receptor area "additional" to that occupied by the corresponding agonist would appear to have important implications to the analysis of receptor mechanisms at the molecular level. Elucidation of the molecular nature of another cholinergic receptor system, the enzyme acetylcholinesterase, is also being attempted through the use of specific, irreversible inhibitors. Belleau and Tani6 3 have recently demonstrated that N,N-dimethyl-2-chloro-2 phenylethylamine inactivates erythrocyte acetylcholinesterase when acetylcholine is the substrate.. Other workers64 have provided evidence that the action of this compound involves alkylation at or near the anionic site of the enzyme, rather then at the esteratic site. Future studies of this sys em may well be conducted with pure, crystalline enzyme, if a recent reporti5 of the crystallization of acetylcholinesterase from eel electric tissue can be confirmed. Changeaux66 has studied the effect of changing ionic strength on an elasmobranch acetylcholinesterase preparation. In solutions of low salt concentratiogthe enzyme tends to form rapidly sedimenting aggregates and displays a high affinity for its substrate as well as for inhibitors like decamethonium. Curare-like drugs, which are ordinarily rather poor inhibitors of the enzyme, actually bind to it rather strongly pnder these conditions. The results are analyzed from a viewpoint that assumes the existence of two conformational states of the enzyme in reversible equilibrium with one another. Mapping studies of acetylcholinesterase have been conducted in the intact electroplax with a series of inhibitory 1-methyl-hydroxyqu:nolinium compounds67. The presence of a hydroxyl group located about 5A. from the quaternary nitrogen (as in 1-methyl-7-hydroxyquinolinium iodide), increases the inhibitory strength more than a hundredfold. Spectral studies of acetylcholine in solution68 support the conclusion that the influence of the quaternary nitrogen on the reactivity of the carbonyl group is inductive in nature and is not transmitted directly through space. C ~ t h b e r thas ~ ~ made a careful study of the effect of various hydrolytic enzymes on acetylcholine-responsive systems in guinea pig
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taenia coli. Hydrolytic enzymes have also proven useful in locating certain steroid hormone receptor systems. Fanestil and Edelman” have provided evidence that aldosterone receptor sites are located in the nuclei of kidney cells, by showing that the action of trypsin or a proteinase from S . Priseus decreases the ability of these nuclear sites to bind H3-aldosterone. The same principle has been employed71 to demonstrate the nuclearmyofibrillar site of estrogenic hormone receptors in the immature rat uterus, bound H3-estradiol being released in this instance. Offermeier and A r i h ~ s ~in ~ ,an extensive and systematic study of the serotonin receptors in rat fundus and calf tracheal muscle, were able to confirm the experimental observations of Woolley and Gommi regarding the effects of sialidase and EDTA on smooth muscle sensitivity towards serotonin. However, they strongly criticized the earlier conclusion that a particular ganglioside is the serotonin receptor. Their work reveals that the observed effects are mainly attributable to EDTA alone, and are probably the result of calcium chelation. Ash and S ~ h i l dhave ~ ~ made a systematic analysis of the various types of histamine receptors, using several histamine analogs. From studies of gastric secretion, inhibition of uterine stimulation with carbachol, and stimulation of ileal smooth muscle, they conclude that there are at least two classes of histamine receptors. Leading concepts ofthe nature of the analgesic receptor, as well as pertinent stereochemical studies of narcotic analgesics,have been reviewed by Port~ghese~~. Differing modes of drug-receptor association and the phenomenon of induced fit are favored as possible explanations for some of the complexities that characterize structure-activity relationships in this field. Two symposia7 5 ~ 7 6dealing with water and its structural significance in biological systems offer provocative reading for those interested in receptor mechanisms.
Instrumental Methods The elucidation of macromolecular structures, and the investigation of how smaller molecules such as substrates bind to these substances, continues to be successfully accomplished through the use of modern physical techniques. It seems inevitable that these methods will make important contributions to future studies of receptor systems. The egg-white lysozyme story, involving the first successful elucidation of the three-dimensional structure of an enz me by x-ray crystallographic anaasis, has been well etudies79 of the egg-white enzyme told by P h i l l i p ~ ~ ~ ,NMR ~ ~spectroscopic . have revealed perturbations of the amide group in certain N-acetamido sugars bound as substrates. In general, x-ray structural studies of biochemical interest8’ are being reported with increasing frequency. For example, two groups have
Chap. 22
Bloom
R e c e p t o r Theory
235 -
just described the s tructure of the complex enzyme, ribonuclea~e~~'~~. Computer-based approaches to molecular modsl-build,inga4 offer promise as potentially facile methods of gaining structural information about complex molecules of biological interest. Circular dichroism studies of proteins and nucleic acidsa5 are providing useful data on conformations in solution and their modification by various agen s. Studies of the binding of N-acetylglucosamine to eggwhite lysozyme8' and of acetazolamide to human carbonic anhydrasee' exemplify the application of this technique to the measurement of conformational changes induced in enzymes by small molecule substrates and inhibitors. References 1. E. D. Korn, Science, 153, 1491 (1966). 2. A. A. Benron, J. Am. O i l Chemists' SOC., 265 (1966). 3. D. E. Green and 0. Hechter, Proc. Nat. Acad. S c t . U.S., 3, 318 (1965). 4. D. E. Green and J. F. Perdue, Proc. Nat. Acad. S c i . U . S . , 55, 1295 (1966). 5. D. E. Green and A. Tzagoloff, J. Lipid Res., 1, 587 (1966)6. D. E. Green and R. F. Goldberger, "Molecular I n r i g h t s i n t o t h e Living Process," ACademic Press, New York 1967, p. 222. 7. R. 0. Brady and E. G. Trams, Ann. Rev. Biochem., 33, 75 (1964). 8. M. R. Hokin, A b r t r a c t of Seminar i n Contemporary Biochemistry, U. of Wisconsin, Oct. 27, 1965, p. 1. 9. J. L. K.vcmau, Nature, 525 (1963). 10. J. L. Kavanau, "Structure and Function i n B i o l o g i c a l Membranes," Holden Day, San Franciroo, 1965. 11. D. T. Warner, Science, 153, 324 (1966). 12. Ann. N.Y. Acad. Sci., 137, 403 (1966). 13. J. Am. O i l C h e m i s t s ' S O C . , ~ 257 , (1966). 14. C. B. A n r e l l and J. N. Hawthorne, "Phorpholipidr," E l s e v i e r , Amsterdam, 1964. 15. L.L.M. van Deenan i n "Progrcrr i n the Chemistry of F a t s and Other Lipids,'' Vol. 8, R. T. Holman, Ed., Pcrgamon P r e s s , London, p. 1. 16. R.M.C. h w r o n i n "Es8ays i n Biochemistry," Vol. 2, P.N. Campbell and G. D. G r e v i l l e Eds., Aoademic Press, London, 1966, p. 69. 17. G. B. Ansell, Adv. Lipid Res., 2, 139 (1965). 18. L. E. Hokin and M. R. Hokin, ScL. Am., 213, 78 (1965). 19. L. S. Wolfe, Can. J. Biochem., 42, 971 (1964). 20. A. R. Tarlov and E. P. Kennedy, J. Biol. Chem., &O, 49 (1965). 21. E. P. Kennedy, C. F. Fox, and J. R. C a r t e r , J. Cen. P h y s i o l . , 9, 347 (1966). 22. C. F. Fox and E. P. Kennedy, Proc. Nat. Acad. S c i . U.S., 54, 891 (1965). 23. C. J. Duncan, Nature, 210, 1'229 (1966). 24. M. Rodbell, J. Biol. Chem.. & 130 (1966). 25. D.F.H. Wallach and P. H. Zahler, Proc. N a t . Acad. S c i . U . S . , 56, 1552 (1966). 26. J. Lanard and S. J. ginger, Proc. Nat. A c d . S c i . U.S., 56, 1828 (1966). 27. L. Warren, M. C. C l i c k and M. K. Nars, J. Cell. P h y s i o l . , 68, 269 (1966). 28. E. C. Lapetina, E. F. Soto and E. De R o b e r t i r , Biochim. Biophyr. Acta, 135, 33Q967) 29. R. Coleman and J . B. Finean, Biochim. Biophyr. Acta, 125, 197 (1966). 30. P. Eranelot. C. J. Bar. E. L. Benedetti and Ph. Rumke, Biochim. Biophvr. Acta, 2,126 (1964). 375 (1966). 31. P. Emmelot and C. J. BOB, Biochim. Biophyr. Acta, 369 (1966). 32. P. Enrwlot and C. J. BOB, Biochim. Biophyr. Acta, 33. A. H. Maddy and B. R. Malcolm, Science, 150, 1616 (1965). 34. D. Chapman, V. B. knut, J. de Gier and S. A. Penkott, Nature, 213, 74 (1967). 35. J.-P. Changoax, J. Thic'ry, Y. Tung and C. K i t t e l , Proc. N a t . Acad. S c i . U.S., 335 (1967). 36. J. Monod, Science, 154,475 (1966). 37. Ann. N.Y. Acad. S c i . , 139, 541 (1967).
u,
m,
m, m,
z,
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38. 39. 40. 41. 42. 43. 44. 45. 46. 47.
48. 49.
50. 51. 52. 53. 54. 55. 56. 57. 58. 59. 60. 61. 62. 63. 64. 65. 66. 67. 68. 69. 70. 71. 72. 73. 74. 75. 76. 77. 78. 79. 80. 81. 82. 83. 84. 85. 86. 87.
Sect. V
-
Topics i n Biology
Tabachnick, Ed.
I. M. Goldman, Advan. Drug. Res., 2, 121 (1966). B. M. Bloom, Am. Cham. SOC. Abrtr. of Papers, 152nd Mtg., New York, N . I . , Sept. 1966, Abstr. P. 39. J. Clauren and B. Formby, Nature, 213, 389 (1967). J. F. Moran, M. May, H. Kinelberg and D. J. T r i g g l e , Mol. Pharmacol., 2, 15 (1967). M. May, J. F. Moran, H. K i w l b e r g and D. J. Triggle, M o l . Pharmacol., 3, 28 (1967). J. E. Lawir and J. W. M i l l e r , J. Pharmacol. Exp. Therap., 154, 46 (196;). J. E. L a w i r , "The S y n t h e r i r of Phen~xybcnzarnine-H~and I t 8 P o r s i b l e U s e f o r t h e Study of Receptorm" (Ph.D. T h e r i r , U. of Wirconsin, 1966), University Microfilmr, I n c . , Ann Arbor, Michigan, 1966. M. S. Yong, M. R. Parulekar, J. Wright and G. S. MarkL, Biochem. Pharmaeol., g, 1185 (1966). S. D i k s t e i n and F. G. Sulman, Biochem. Pharmacol., l4, 739, 881 (1965). J.D.P. Graham and H. A 1 U t i b , B r i t . J. Pharmacol., 2,1 (1966). J. S. G i l l e r p i e and D.N.H. Hamilton, Nature&& 524 (1966). J. S. G i l l e r p i e , Proc. Royal SOC. (London), 1 (1966). 1,U,24(1%% P. N. P A t i l , J. B. LaPidur and A. Qe, J. Pharmacol. Exp. Therap., P. N. P a t i l , J. 8. LaPidus, S. Molinari and A. ?ye, J. Pharm. S c i . , 56, 287 (1967). J. H. B i e l and B.K.B. Lum i n "Drug Reraarch," Vol. 10, E. Jucker, Ed., B i r k h k s e r Verlag, Basel, 1966, p. 46. P. P r a t e s i , L. V i l l a and E. Grana, Farmaco, Ed. S c i . , 2l, 409 (1966). M. Wenke,,Adv. 5 i p i d Res., 4, 69 (1966). J. Eepelik, M. Cernohorakf, D. Lincovdand M. Wenke, Arch. I n t e r n . Pharmacodyn, 165. 37, 45, 53 (1967). J. M. Bowners, Science, 152, 1370 (1966). G. Wald, Science, 150, 1028 (1965). S. M k r t e i n 8nd F. G. Sulman, J. Theoret, B i o l . , 2,385 (1966). K. Takagi, M. Aka0 and A Takahashi, Life S c i . , 4, 2165 (1965). E. W. G i l l and H. P. Rang, Mol. Pharmacol., 2, 284 (1966). E. J. Arii'ns and A. M. Slmonie, Parmco, Ed. S c i . , 21, 517, 581 (1966) E. J. Ariens i n "Drug Research," Vol. 10, E. Jucker, Ed., B i r k h h s e r Verlag, Basel, 1966, p. 429. B. Belleau and H. Tani, Mol. Pharmacol., 2, 411 (1966). J. E. Purdie and R. A. McIvor, Biochim. Biophys. Acta, 128, 590 (1966). W. Leuzinger and A. L. Baker, Proc. Nat. Acad. S c i . U.S., 446 (1967). J.-P. Changeux, Mol. Pharmacol., 2, 369 (1966). T. R. Podleskl and D. Nachmansohn, Proc. N a t . Acad. S c i . U . S . , 1034 (1966). J. H. Fellman and T. S. F u j i t a , Nature, 211, 848 (1966). A. W. Cuthbert, J. Pharm. Pharmacol., l8, 561 (1966). D. D. F a n e s t i l and I. S. Edelman, Proc. N a t . Acad. S c i . U . S . , 56, 872 (1966). W. D. Noteboom and J. Gorrkl, Arch. Biochem. Biophyr., 111,559 (1965). J. Offermeier and E. J. Arii'ns, Arch. I n t e r n . Pharmacodyn, &, 192, 216 (1966). A.S.F. Ash and H. 0. Schlld, B r i t . J. Pharmacol., 27, 427 (1966). P. S. Portoghese, J. Pharm. S c i . , 55, 865 (1966). Fed. Proc., 25, 951 (1966). Ann. H. Y. Acad. Sci., 125, 249 (1965). D. C . P h i l l i p s , S c i . Am., 215, 78 (1966).
B. M. Bloom and
E,
&,
a,
E. P. Oaserman, Science, 155, 1536 (1967). E. W. Thomas, Biochem. Biophys. Res. Commun., &, 611 (1966).
J. Kraut, Ann. Rev. Biochem., 2,247 (1965). E d i t o r i a l (anon.), N8ture, 852 (1967). G. Kartha, J. Bello and D. Harker, Nature, 862 (1967). H. P. Awy, M 0 . Boles, C. 8. Carlirle, S. A. Evans, S. J. Morris, R. A. Palmer, B. A. Woolhouse and S. S h a l l , Nature, 21l, 557 (1967). C. Levinthal, S c i . Am., 42 (1966). S. Beychok, Science, 154, 1288 (1966). A. N. Glazer and N. S. Simmons. J. Am. Cham. SOC.. 88. 2335 (1966). J. E. Coleman, Biochemistry, 5; 2644 (1965).
u,
a,
~
-I
237
D.A.
Chapter 23. F a t e and D i s t r i b u t i o n o f Drugs Buyske and D. Dvornik, Ayerst L a b o r a t o r i e s , Montreal, Canada.
The p r e s e n t c h a p t e r h a s been w r i t t e n t o b r i n g t h e review p r e s e n t e d l a s t y e a r up t o d a t e . Approximately 1100 r e f e r e n c e s as l i s t e d i n t h e Ringdoc A b s t r a c t s were examined; amongst them, 70 were s e l e c t e d from t h o s e r e p o r t i n g e i t h e r new f i n d i n g s o r biochemical t r a n s f o r m a t i o n s o f s t r u c t u r e s n o t mentioned l a s t y e a r . Again, data are a r r a n g e d i n t a b u l a r form and i n c l u d e main pharmacodynamic p r o p e r t y , chemical name o r t h e g e n e r i c name a s l i s t e d i n t h e Merck Index; s t r u c t u r a l formula ( * i n d i c a t e s u s e o f r a d i o a c t i v e compound), w i t h arrows i n d i c a t i n g s i t e ( s ) o f biochemical r e a c t i o n ( s ) d e s c r i b e d i n t h e accompanying t e x t . A b b r e v i a t i o n s used: UCC, unchanged ( p a r e n t ) compound; (MI major; ( m ) minor; ( t r ) t r a c e ; (A) pharmacologically a c t i v e ; conj. f o r conjugated; g l u c . , g l u c u r o n i d e and s u l f . , s u l f a t e , respectively. Upon examination o f t h e r e p o r t s d e a l i n g w i t h some a s p e c t o f d r u g metabolism and p u b l i s h e d i n 1966, we have been l e f t with t h e f o l l o w i n g impressions. F i r s t l y , one is overwhelmed by t h e number o f s t u d i e s e x p l o r i n g t h e metabolic f a t e o f d r u g s and r e l a t e d s u b s t a n c e s . It a p p e a r s t h a t such s t u d i e s a r e b e i n g undertaken as soon a s a pharmacologically a c t i v e substance begins t o look l i k e a p o t e n t i a l candidate f o r c l i n i c a l i n v e s t i g a t i o n s . O f t e n , l a b e l l e d compounds a r e used; i n t h e p a s t , conc l u s i o n s from a b s o r p t i o n , d i s t r i b u t i o n and e x c r e t i o n s t u d i e s were based on d a t a r e p r e s e n t i n g r e c o v e r i e s o f t o t a l r a d i o a c t i v i t y , i.e. comprising t h e p a r e n t compound as w e l l as i t s m e t a b o l i t e ( s ) ; nowadays, a n a t t e m p t i s u s u a l l y made t o r e c o g n i z e t h e main biochemical t r a n s f o r m a t i o n ( s ) o f a s u b s t a n c e so as t o d i f f e r e n t i a t e t h e unchanged p a r e n t s u b s t a n c e from i t s m e t a b o l i t e ( s ) i n r e s p e c t t o d i s t r i b u t i o n , l i f e - t i m e and e x c r e t i o n a n d , e s p e c i a l l y , t o uncover whether pharmacodynamic a c t i v i t y i s due t o t h e p a r e n t s u b s t a n c e or t o i t s m e t a b o l i t e ( s ) . A s a consequence, d a t a and e x p e r i e n c e g a t h e r e d from such s t u d i e s a f f e c t t h e f u t u r e o f a pharmacologi c a l l y a c t i v e s u b s t a n c e i n more t h a n one way. Regarding t h e biochemical t r a n s f o r m a t i o n s which o c c u r on a s u b s t a n c e i n v i v o , i n s p i t e o f v a r i a t i o n with s p e c i e s , t h e m e t a b o l i c f a t e o f many a compound can be a n t i c i p a t e d w i t h a c o n s i d e r a b l e degree of c o n f i d e n c e ; t h i s can be done because t h e r e a r e only few biochemical r e a c t i o n s involved i n t h e p r o c e s s o f r e n d e r i n g c i r c u l a t i n g s u b s t a n c e s more h y d r o p h i l l i c - though n o t n e c e s s a r i l y l e s s b i o l o g i c a l l y a c t i v e o r l e s s t o x i c . The p a u c i t y o f t h e s e biochemical r e a c t i o n s coupled with t h e p r a c t i c a l l y u n l i m i t e d number o f s u b s t a n c e s which a r e , or which can be m e t a b o l i z e d , r e f l e c t t h e low degree o f s u b s t r a t e s p e c i f i c i t y o f t h e enzyme s y s t e m ( s ) d e t e r m i n i n g t h e f a t e o f a Substance i n v i v o ; t h e enzyme s y s t e m ( s ) involved i n hydroxyla t i o n ( s ) , f o r example, can h y d r o x y l a t e a g r e a t v a r i e t y o f s t r u c t u r a l l y q u i t e d i f f e r e n t compounds.
238 -
Sect. V
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T o p i c s in Biology
T a b a c h n i c k , Ed.
A t t h i s point it is p e r t i n e n t t o r e c a l l t h e c a p a c i t y of many substances t o a l t e r enhance o r block t h e a c t i v i t y of enzyme system(s): while l a s t i n g , t h e change may a f f e c t not only t h e f a t e of t h e substance which caused i t ; because of t h e low s u b s t r a t e s p e c i f i c i t y mentioned above, t h e change may a l s o a f f e c t t h e f a t e of any o t h e r s u b s t r a t e subsequently i n c o n t a c t with t h e r e s p e c t i v e enzyme system(s). It i s of considerable importance t o t a k e t h e phenomena of enzyme i n h i b i t i o n and, p a r t i c u l a r l y , of enzyme i n d u c t i o n i n t o c o n s i d e r a t i o n whenever t h e b i o l o g i c a l a c t i v i t y o r t h e metabolic f a t e of a compound is e i t h e r discussed, s t u d i e d o r r a t i o n a l ized. Appreciation of t h e s e phenomena may r e s u l t i n more frequent use of a g e n t s known t o a f f e c t t h e a c t i v i t y of microsomal enzyme systems €or a s p e c i f i c purpose: t o a l t e r t h e p h y s i o l o g i c a l o r t h e pharmacodynamic e f f e c t s of endogenous or exogenous substances merely by a l t e r i n g t h e i r metabolic fate.
-
-
An i n s p i r i n g , and l i k e l y t h e f i r s t , example f o r t h e t h e r a p e u t i c a p p l i c a t i o n of enzyme induction t o a f f e c t t h e metabolic f a t e of an endogenQus substance h a s r e c e n t l y been r e p o r t e d by Yaffe and h i 6 a s s o c i a t e s (71): phenobarbital treatment has been used t o prevent hyperbilirubinemia: by inducing t h e glucuronyl t r a n s f e r a s e , enhanced glucuronide formation enabled i n c r e a s e d b i l i r u b i n e x c r e t i o n and r e s u l t e d i n decreased serum b i l i rubin concentration.
Chap. 2 3
Fate of Drugs
Buyske a n d Dvornik
239 -
SOME MhTTBBOLIC TRANSFORMATIONS REPORTED I N 19 6 6
N e w metab. o f propylbrornide ( I ) i n rat is n-propylmercapturic a c i d sulf o x i d e (14%). trace of S-contg.
5 . h
metab. s u g g e s t t h a t S-alkyl. c y s t e i n r e s i d u e s formed only with (I) (1). Haloalkanes gen. metab. t o mercapt u r i c ac. and similar S-linked conj. Addl. metab. r e a c t i o n i s hydroxyl a t i o n (2).
CII CH CH X 3 2 2
1-Halopropanes (X=C1, B r , I)
I n r a t , man: oxid. t o Me2S02 ( r a t ,
15%; man, 3%); rest is UCC (3).
0
I1
Ii C-S-CH
't
3
Dime thy l s u l f o x i tie
bie t h y lhy d r a z i n e (a=€{, o r CH 1
In
r a b b i t , UCC ( 3 5 $ ) , red. t o Me2S (exh a l e d ) ; oxid. t o Me2S02 (9.5%) (4). IYe2S02 ( i . p . 1 . i n r a t (64%) ( 3 ) and r a b b i t s (75%) ( 4 ) excr. as UCC. Me$ ( i . p . 1 , i n r a b b i t : UCC ( e x h a l e d ) ; Me2SO (approx. 9%) and Me2S02 (approx. 10%) ( i n u r i n e ) ( 4 ) .
I n r a t : oxid. dernethyl. t o C02 for dimethyl d e r i v . dependent on dose; approx. 50% of monomethyl d e r i v . demethylated t o e q u a l q u a n t i t i e s o f C02 and C€I4(5).
.+
3
Toxic. from B l i g h i a s a p i d a
i b
H2C 7 C H 2 S H C O C H NH2
Hypoglycin A
I n r a t s , r a p i d l y oxid. I n v i t r o , transamin. and decarbox. t o rnethylene-cyclopropaneacetate (61, which b l o c k s f a t t y a c i d ()ClO)oxid. i n v i t r o ; tox. of hypoglycin prob.due t o t h i s metab. ( 7 ) .
240 -
Sect. V - T o p i c s i n Biology
T a b a c h n i c k , Ed.
Surfactant
ca CH
1‘
I n r a t : UCC ( 6 0 % ) ; 2-ethyl-2,3dihydroxyhexanoic a c i d (30%); 2e t h y l h e x a n o y l g l u c . (5%); 2 - e t h y l hexanol (1%). I n r a b b i t s , mainly
ucc (8).
Hypoglycemic 3-Hydroxy-deriv. o n l y metab. i n g u i n e a p i g , mouse, rat and r a b b i t . Hypoglycemic e f f . p r o p o r t i o n a l t o UCC: h i g h i n r a t , none i n r a b b i t . I n man, o n l y UCC ( 9 ) . i-Uutylbigumide*
I n r a b b i t , t h e N-0-C $uc. isolated and i d e n t i f . ; i n c o n t r a s t t o N-gluc. , t h e N-0-C g l u c . is completely h y d r o l . by p-glucuronidase (10).
N- Ace tyl-I;-:,hen.rlhydroxyln.?iine
CNS S t i m u l a n t
UCC, rat ( m ) , dog (M), monkey (M) (ll), man (MI (12,131,r a b . ( t r ) ; p O H and g l u c . , r a t (I41 , dog (m), monkey ( t r ) (111,r a b . , man ( m ) (12); benzylmethylketone, rab. (m) , dog ( t r ); phenylpropanol r a b . ( m ) , dog ( t r ) (12); h i p p u r i c a c . , r a t ( t r ) , dog (M), monkey (m) (111, r a b . , man (N) (12,131. I n r a t . d i f f . i n metab. o f ( + ) and ( - ) forms (12).
Chap. 2 3
Fate of D r u g s
Buyske a n d Dvornik
241 -
I n r a b b i t : p-OH-phenylacetate major metab. Also, p-oxid. * oxid. deam., rn-hydrox. and m-0-methyl.; i m p o r t a n t f i n d i n g : depending on s e q u e n c e , octopamine (approx. Fb) and/or c a t e c h o l a m i n e s a r e formed (14).
Ty r amine
*
An t i b i o t i c
I n c u l t . medium o f b a c t . growing on chloramphenicol a s s o u r c e o f C , s e r i e s of metabolites i d e n t i f i e d , i n d i c a t i n g stepwise degradation t o P-carboxy-cis,cis-muconic a c i d (15).
Chloramphenicol
Anti-inflammatory
CII (CIi ) 0 ~ 3 2 3
c
H
)
&
I n r a t , UCC (m); o f t h e 11 metabol i t e s , 4-butoxyphenylacetamide and corresp. a c i d i d e n t i f i e d . Rapid a b s . and d i s t r i b . ( r a t , r a b b i t ) ; a f t e r 48 h r approx. 456 i n u r i n e , 30"k i n f a e c e s (UCC) (16).
4 - B u t o x y ~ h e n y l a c etyl-hpdroxami c a c i d?v
Analgesic
J
Ace tophene t i d i n e
I n man, r a t : UCC ( t r ) ; G-dealkyl. and g l u c . (man 28%, rat 22%), s u l f . (man &b* r a t 6%); rn-hydroxyl. ( r a t , (0.01%). o-Sulfonyloxy-metab. is new (17). 2-Hydroxyl. new metab. i n c a t , dog, man; a l s o , N-OH-metab. ( t r ) (18).
242 -
Sect. V - Topics i n Biology
Tabachnick, Ed.
Hypoglycemic
Z i O X 2A
@I
M k ( C E ) CH
3
*
Tolbutsmide
I n man, 85% recovered a s 4-CH20Hand 4-COOH m e t a b o l i t e s . I n r a t , 4C&OH (M) with 4-COOH ( t r ) and Ndealk. ( t r ) . U s e o f 3H-label c l a r i f i e d e a r l i e r discrepancies. In rat, r e l . amts. of m e t a b o l i t e s n o t changed a f t e r c h r o n i c admin. (19).
A n t i -1eprosy
H2N
0
I n man, t h e s u l f o n e w e l l abs. and excr. (75%/24 h r ) , slowly metab.: UCC (up t o 41%, pH-depend. >;probably N-conj. ( g l u c . ) (27%). Corresp. s u l f o x i d e l e s s w e l l absorbed; oxid. t o s u l f o n e (10%) (20).
Dapsoce
Herbicides
-+kq;
2,6-Dichlorobenzonitrile (R=CN) 2 * 6-Dichlorothiobenzamide ( lI=CSNHT)
Insecticide
I n r a t , r s b . , dog: r a p i d a b s . , metab. and excr. UCC ( t r ) ; 3-011 (M), 4-OH ( M ) and conj. ( g l u c . , sulf., m a r c a p t u r i c a c . ) ; CN hydrol. ( t r ) (21.22). F a t e o f thiobenzamide similar* as n i t r i l e major metab. ( 2 1 ) . P h e n o l i c metab. uncouple oxid. phosp h o r y l . , may e x p l a i n hepatotox. ( i n rab.) (23).
\ J . Completely metabolized i n r a t , dog; 0 - d e s - e t h y l a t i o n with s i d e - c h a i n dec h l o r i n a t i o n , dephosphorylation and s i d e - c h a i n oxid. t o produce 6-7 m e t a b o l i t e s (24).
Fate of Drugs
Chap. 2 3
Buyske and Dvornik
243 -
Muscle relaxant
H3C
I
c-
.OCH2
O
H C \5
O
Retaxalone
In dog, man: oxid. of 3-methyl to COOH (27%) followed by conj. (gluc. (1%); cleavage of ether bond (m). Rapid excr. (48 hr) in rabbit (96%) and rat (71$), slow in dog (11%). Metabolism similar in rabbit and dog, different in rat ( 2 5 ) .
Coccidiostat In chicken: ester hydrol. ( 2 0 % ) . with (a) N-des-acetylation (15$), (b) N-des-acetylation, 5-hydroxyl. and conj. (sulf. (256) ; unident. conj. ( 2 5 % ) ( 2 6 ) .
Ethopab-3teW
CN depressant
UCC, rat (M) , rabbit ( m > ; progressive oxid. of glycerol chain: corresp. deriv. of a-OH-propionic acid, rat (m), rabbit (M) and of acetic acid, rat (m) , rabbit (tr). Both metabolites lack CN depressant act. (27).
CIi 6’
3
Keprophendiol Hallucinogen +.H,CO
LL
CI12 CH2XH2
Me scalin*
\
In man: rapid abs., metab. and excr. (87%); UCC (55-6M); oxid. deamin. (27-30%); N-acetylation (0.1%); N-acetylation and 5-0-demeth. ( 7 6 ) . Fattern of metab. in cerebros p . fl. indicates N-acetyl. more important in CNS than oxid. deamin. N-Ac-metabolite inact. in man (28).
2 44 -
Sect. V
- Topics i n Biology
Tabachnick, Ed.
Estrogen
I n r a t , conj. (monogluc. and 3 u n i d e n t i f i e d m e t a b o l i t e s ; glucuronide e x c r e t e d v i a b i l e (29).
St i l b e s t r o l *
Carcinogen
\
I n r a b b i t , 7 m e t a b o l i t e s which i n c l u d e h y d r o x y l a t i o n w i t h conj. ( g l u c . , s u l f . ; N-gluc ; r e d u c t i o n and f i s s i o n o f azo-bond ( 3 0 ) .
1-Phenylazo-2-neph t h o 1 Antioxidant
C(cH3)3
In rat, dibenzylether is s p l i t with subsequent o x i d a t i o n t o c o r r e s p . benzoic a c i d (M) and i t s e s t e r gluI n t e r m e d i a t e aldehyde c u r o n i d e (M.). a l s o found (m) (31).
Antituberculosis
I n man ( 3 2 1 , mice, r a t s and dogs, ethionamide and t h e s u l f o x i d e ( i t s metab.) are i n t e r c o n v e r t i b l e : both a p p e a r i n b l o o d , i r r e s p . o f which cpd. w a s given ( 3 3 ) . Ethioniamide
Buyske and Dvornik
Fate of D r u g s
Chap. 2 3
245 -
Anti -choline s t e r a s e - i n h i b i t o r XGX 4 It
CH
2Bf
iQCH II
I n r a t (i.p.1: UCC ( l a r g e q u a n t . ) ; d e h y d r a t i o n t o mono-CN m e t a b o l i t e ; additional metabolites detected
(34).
TFI3-4
*
I n man,
6-0x0 m e t a b o l i t e is new
(35).
Met h y p r y l o n
I n dog, t h r e e new m e t a b o l i t e s i s o l a t e d : 3’-carboxy-, s u l f o x y and s u l f o n o - d e r i v a t i v e s o f b a r b i t u r i c a c i d (36). Kethitural
I n r a t , o x i d a t i o n o f t e r m i n a l Ca t . t o a c i d (MI o f i n t e r e s t s i n c e is u s u a l l y , penultimate C-at o x i d i z e d . Addl. metab. found ( t r ) (probably u n s a t . a l c o h o l ) (37).
.
5-Ethyl-5-crotylbarbituric
acid
-
Sect. V
246
Topics i n Biology
Tabachnick, Ed.
Ant i p r o tozoa
c2;:
Metab. p a t t e r n similar i n man and dog: UCC 0 6 0 % ) ; oxid. of CH20H t o COOH 0 2 5 % ) ; e t h e r gluc. o f CH20H 0 5 % ) ; no r e d u c t i o n of NO2 d e t e c t e d
CB,
I
(38).
J
Me t r o n i d a z o l e
Major m e t a b o l i t e ( i n f a e c e s ) i s 5,6-dihydro-6-( 2-thienyl ) imidazo [2 (1b l t h i a z o l e , more p o t e n t a n t i h e l m i n t i c t h a n p a r e n t drug. F i n d i n g l e d t o s y n t h e s i s of t e t r a m i s o l e ( c o r r e s p . 6-phenyl-thiazoline d e r i v . ) , p o t e n t broad-spectrum a n t i h e l m i n t i c (39,401.
Anthelmintic
CGCE,
Thiazo thit.nol
J
CCH ./
1
ii21i
Metab. o f CH3O-subst. 6 - s u l p h a n i l arnidopyrimidines depends on pos. of CH3O; e.g. ( a ) 2,4,5-(0CH3)3: N ' conj. ( g l u c . ) , monkey (MI, r a t , r a b . ( m ) ; N4-acetyl., monkey ( m ) , rat ,rab. (M); ( b ) 2,5-(OCH3)?: UCC (MI; N4a c e t y l . ( t r ) ; N4-conj. ( g l u c . , s u l f . )
( t r ) (41).
S u l f a d i u e thoxine
LCII
03 OH
\
3
T
Metab. s t u d i e s with t h e c i s - and t r a n s - form i n t h e r a t s u g g e s t t h a t interconversion occurs v i a oxidation t o ketone and r e d u c t i o n back t o a l c o h o l (42 1.
Chap. 2 3
F a t e of D r u g s
Buyske and Dvornik
247
The metabolism o f t h e i s o m e r i c forms o f 1- and 2-decalone was investig. i n the rabbit: reduction t o a l c o h o l (10-50%) and conj. ( g l u c . ) (20-50%) (MI (43). Decalone, 1 o r 2
Insecticide Ci
c1
c1 Dihydroaldrin
-
I n h o u s e f l y and p i g microsomes:
mixt. o f endo- and exo-6-08-metab. I n h i b . o f h y d r o x y l a t i o n by s e s o x a n e , may account f o r synergism i n vivo. In v i t r o , dihydroaldrin i n h i b i t s c o m p e t i t i v e l y t h e e p o x i d a t i o n of a l d r i n (44).
Adrenergi c 8- blocker I n mice, r a t s , guinea p i g and man: UCC ( t r ) ; conj. (gluc. 1; 4'-hydroxyl a t i o n followed by conj. ( g l u c . ) (M); o x i d a t i v e deamination (approx. 3096) (45). Fropranolol
Anti - i n f lamma t o r y Not metabolized i n r a t , r a b b i t , I n man, 50% excr./24 h r . I n man. r a b b i t , 48% undergoes t u b u l a r rea b s o r p t i o n (46).
Kapht h y p a n i d e
Sect.
248
V - Topics
i n Biology
Tabachnick, Ed.
S tiruluzts
Cil,
m2A1 I ’
qki CNBGH
\
k
i;
Nydroxylamine moiety reduced to corresp. amine by mouse tissues. Ketab. probably responsible f o r stimu1;int action (47).
Ic do lyl a l k y ih y eroxyI m i ne s (;?I=!i o r C53) In rat: oxid. to corresp. acid
(93%));conj. (prob. with glycine) (m); hence, 5-methoxyindole-3-acetate acid in pineal tissue is probably a metabolite of 5-methoxytryptophol rather than the product of pineal hydroxyindol-0-methyltransferase
(48).
In rat, Cuinea pig, rabbit: O-desmethyl. of 5-0313 and 6-OCii3 derivs. ; 5-hydroxyl. and partial G-des-methyl. of 4-GC1i3 and 7-0CiI3 derivs. In vitro 0-des-methyl. in rat liver slices, but not in microsom. prep. (49).
In vitro comparison of 0- snd Nilemethyl. and ring-hydroxyl. of 4isomeric methoxy- and N-rnethylmethoxyoxindoles by rat. guinea pig and rabbit liver microsomes. Large differences noted (50). Methoxyoxindoles
B u y s k e and Dvornik
Fate of D r u g s
Chap. 2 3
Diagnostic aid Food colour n
;
,
.
a
\
n
a N
3
f Tj
i!i
w 03r;a
s
249 -
In rats (i.v.1, bile (10$/30 min), urine (657/6 hr): UCC (45%). isatin5-sulfon. ( 6 $ ) ; orally, (12%), poor sulfoanthranilate abs. ( 3 ? / 7 2 hr urine). Interpretation of kipiney function test may be complicated if dye is metabolized in humans (51).
/
11
F1) and C Blue N o . 2 % & n o s tatic
In rat, 30% UCC; three minor metabolites formed: one unidentif., other two are sulf. conj. of phenolic OH of corresp. indole derivs., with and without retention of semicarbazone ( 5 2 ) .
I
Cii,
, kdrenochrome sernicarbazone
*
V i i . E-act.
In rats, both cpds. have similar absorption and distribution pattern. Same final metabs. as a-tocopherol, '3 but vit. E-act. not due to metabolism to a-tocopherol (53).
TIi3 (Cii2CE2CE2CH) C F H C
3
m
CH
CR
3
3
(iil=CE3,
*
II2=EI) jF. N-Me thyl-Y-tocopheramine(21=11, i?2=CH3)
c1 -,ocopheramir:e
U rA
lj-R
CH CIi2CH2X 3 (a) X=II; ( b ) X=OH
Chloroquine ( Ia) , Nydroxychloroquine (Ib): In man: UCC (6U;g); Ndesethyl. (37"k); N-bis-desethyl. ( 3 % ) ; oxid. deam. (tr), subsq.redn. or oxid. (monkey). Metab. of netabs. reported (54). Glycerylaminophenaquine ( I1 : In man: UCC;. hydrol. to corresD. free acid (M); no conj. (55,561.
Sect. V - Topics i n Biology
2 50 -
Tabachnick, Ed.
Antihypertensive I n dog: UCC ( 1 5 % ) ; t r a n s a m i d i n a t i o n t o a r g i n i n e ( W ) (5%)and g u a n i d y l acetate, the l a t t e r giving rise t o c r e a t i n e (10%) and c r e a t i n i n e ( 1 5 % ) ; h y d r o l . t o u r e a (4%), b u t no desirnidation; aromatic hydroxylation (4%>,p r o b a b l y a t C-7 (57).
+
Gui7noxan Hypnotic
CH-
I n r a t , man: UCC; hydroxyl. and c o n j . ( g l u c . ) (14) (58). I n r a t , r a b . , dog, Rhesus monkey, man: 3'-011; 4'OH; 6-011; hydroxyl. o f 2'-CX3. I n r a t , r a b . : 8-011( t r ) ; hydroxyl. of 2-CH3 ( n o t i n man) (58,591. A l l OHmetab. are l e s s a c t i v e and l e s s t o x i c ( e x c e p t 2I-CH20H) (59).
Ke t h a q u a l o n Xanthine Oxidose I n h i b i t o r
CII
I n mice, dogs and man: 6-hydroxyl a t i o n (M); small amounts o f r i b o s i d e may b e formed ( 6 0 ) .
I
Allopurinol
*
Vasodilator
I n r a t , r a b b i t : UCC ( t r ) ; 5'-OH ( 3 % ) w i t h p a r t i a l c o n j . (gluc.),
CH 3 1-Hexyl-3, ?-dime t h y l x a n t h i n e
(SK-7)
o x i d . t o 5-one ((1%) and hydroxyl. t o 4 ' , 5 ' - d i o l (10-2@/0); o x i d . c l e a v a g e t o 3'-COOH (15-35%); d i o l p a r t l y c o n j . ( g l u c . 1. E q u i l . between 5l-01 and 5'-one. 1-Hexyl enhances l i p i d s o l . , hence ( a ) accel. a b s . (oral, r e c t a l ) and metab. , ( b ) l a c k of Nd e a l k y l . (unchanged u r i c a c . e x c r . )
(61,621.
Chap. 2 3
Buyske and Dvornik
Fate of D r u g s
Antifolic acid
9
251 -
FG0H
I n r a b b i t s , 4,7-dihydroxy d e r i v . i s major metab. Metab. is l e s s t o x i c i n mice t h a n p a r e n t cpd. and h a s lower a n t i f o l i c a c i d a c t i v i t y ; t h i s may e x p l a i n r e s i s t a n c e of r a b b i t t o cytotox. o f m e t h o t r e x a t e ( 6 3 ) . Methotrexate Psychotropic appnt
Nine metab. formed, similar i n r a b . , dog and man: r e d u c t i o n of k e t o n e , h y d r o x y l a t i o n of C-2 o f s i d e c h a i n and s e l e c t i v e 0-demethylation w i t h conj. ( g l u c . ) (64). l’etrabenazine
J
R e l . low r a t e o f excr. i n r a t s , r a b . , man. UCC ( r a t ) ; d e s - a c e t y l . ; b i s - d e s - a c e t y l . , r a t (MI and conj. ( g l u c . ); C=C c l e a v a g e , man (M) and conj. ( g l u c . ) . I n r a t s , bulk excr. i n f a e c e s . S i m i l a r d a t a with f r e e di-phenol (65).
~is(4-acetoxyphenylicyc~ohexy~idene re thane
*
Tranquilizer
J I n r a t , r a p i d a b s . , slow e x c r . ; ( g l u c . ) ( r n ) ; oxid. t o s u l f o x i d e (M); N-dealkyl. ( t r ) w i t h conj. ( g l u c . )(rn); a l s o u n i d e n t i f . , p o s s i b l y p h e n o l i c m e t a b o l i t e s found UCC (tr); conj.
(66). Clopenthixol
Sect. V
2 52 -
kr:tico n v u i sant
- Topics in Biology
Tabachnick, Ed.
.1 In rat, rab. , dog: ring hydroxylation (M); 10,ll-bis-hydroxylation (trans) (m); conj. (glut.) (67).
COKE, z
Antidepressant
k
In man: following (I) or (II) 10OH-like derivs. , partly conj. (gluc. ). Lack of 2,lO-bis-hydroxylated metab. may indicate that aromitic (2-OH) and benzylic (10-OH) hydroxyl. represent alternative metab. pathways (68).
Trnnqui liz e r
In man, p-(2-~hlorophenothiazinyl) propionic acid is new metabolite (O.4.k of total) (69).
Chlorpromnzice
'
2
Glucuronide is major metab. in mice, rats, rab., and dogs. Fluorometric assay described ( 7 0 ) .
1. 2.
3.
253 -
Buyske and Dvornik
Fate of D r u g s
C h a p . 23
E. A. Barnsley , T.H. Grenby and L. Young, Biochem. J. , loo, 282 (1966). E.A. B a r n s l e y , Biochem. J. , 100, 362 (1966). H.B. Hucker, P.14. Ahmad, E.A. Miller and F. Brobyn, N a t u r e , 2, 619
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2 54 -
T a b a c h n i c k , Ed.
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G.B. A. Kovensky, G.H. H i t c h i n g s , E. Metz and 9 . Rundles9 Biochem. Pharrnacol. , Q, 863 (1966).
0
(1966 1. Nowak, G. Schorre and R. S t r u l l e r , Arzneimittel-Forsch.
. Elion,
, 16,395 , 16,407
( 1966)
Fate of D r u g s
Chap. 23
61.
vV. Mohler, I. B l e t z and K. Heiser, Arch. Pharmaz.,
62.
d. Mohler, K.
Popendiker and M.
255 -
B u y s k e and Dvornik
9, 448
Reiser, Arzneirnittel-Forsch.,
(1966).
16,
1524 (1966). 1i.M.
64.
3.3. Schwartz, X. Bruderer, J. Xieder and A. B r o s s i , Biochern. Pharmacol., 9, 645 (1966). H. Larsen, Acta pharmacol. t o x i c o l . , 3,337 (1365). I. Xuus, U. ilahl Larsen and P.V. P e t e r s o n , p e r s o n a l communication. Fi. K r a m l , K. S e s t a n j and i). J v o r n i k , p r e s e n t e d i n p a r t a t t h e Xth Ann. Neeting of t h e Zanad. Fed. 3 i o l . Aoc., i'rontreal, J u l y 1967. J.L. C r a m m e r and 3. S c o t t , Psychopharmakol., 461 (1966). C.F. Rodriguez and 3 . i . Johnson, L i f e S c i . , 5 , 1283 (1966). B. h b n i c k , 3.F. iiorcan, C.A. Towne and G.S. F n i l l i p s , J. Pharmacol. 301 (19661. :<xptl. Therap., S.J. Yaffe, G. Levy, T. katsuzawa and T. E k l i a h , New Zngland J. Med.
Xlias, Biochem. Pharmacol.,
425 (1966).
65. 66. 67.
68. 69 70 71
Hedetzki, J.F.
Redetzki and A.L.
2,
63
-
g,
a,
275. 1461 (1966).
,
Chapter 24 The Unknown Variable in Sensitization to Drugs: Drug or Host? Max Samter and G. H. Berryman, Univ. of Ill. Col. of Med., Chicago, Ill. and R. G. Wiegand, Abbott Labs., No.Chicago,Ill. Drug toxicity and sensitization to drugs (which might cause indistinguishable clinical symptoms) differ; toxicity has no immunological connotations while sensitization implies the presence of antibodies. Yet, unexpected toxicity as well as sensitization are likely to be results of the same 'normal' metabolic processes which are applied to any substance which is not part of our internal environment and therefore must be excreted. With insignificant exception, the effective excretion of a drug requires its biotransformation. Deamination, sulphoxidation, 0- and N- dealkylation, hydroxylation of ring structures, oxidation of side chains produce a wide spectrum Some of these metabolites are innocuous of metabolites. ' 9 (as intended), some are toxic, some are neither innocuous nor toxic, but are sufficiently reactive to sensitize, i.e. to form co-valent bonds with macromolecular components of the host and to render them antigenic. It is with the formation of such antigenic determinants, 'haptens', that these reflections are concerned. Since the discussion refers, necessarily, to concepts which have been held for a number of years, the bibliography covers more than the immediate past. Extensive in vitro studies have established that metabolites must meet certain criteria to qualify as 'haptens'. Davies, for instance, listed certain groupings which can be expected to conjugate with protein e.g -"H2 (-N02, -N=N-), -CONH2, -NHOH, -COOH, -OH and quinones', and the list has lengthened in the intervening years. In spite of our in vitro understanding, however, the incidence of clinical sensitization seems to be without rhyme or reason. Drugs are absorbed, transported, metabolized and excreted; sensitization must occur along the way. Information about physical chemistry and biological fate of drugs is generally available. We have abundant data, for example, about solubility, ionization, half-life, protein binding, metabolic handling and mode of excretion of sulfonamides4~5~6;moreover , there is no doubt that sulfonamides are able to sensitize.7
Chap. 2 4
Drug Sensitization
S a m t e r , B e r r y m a n , Wiegand
2 57 -
Considering our f a m i l i a r i t y w i t h t h e pharmacological behavior of d i f f e r e n t sulfonamides, i t i s f r u s t r a t i n g , indeed, t o concede d e f e a t ; no c o r r e l a t i o n appears t o e x i s t between t h e i r s t r u c t u r a l or f u n c t i o n a l c h a r a c t e r i s t i c s and t h e i r tendency t o become a n t i g e n i c determinants. T a b l e I - which has been compiled and averaged from m u l t i p l e sources - p r e s e n t s biochemical and metabolic s t u d i e s of v a r i o u s sulfonamides and n o t e s , f o r each, t h e r e p o r t e d incidence of s e n s i t i z a t i o n . W e have been unable t o f i n d a common denominator. Even so, i t i s i n s t r u c t i v e t o take a c r i t i c a l look a t c e r t a i n hypotheses which have been advanced. A s h o r t h a l f - l i f e , f o r i n s t a n c e , does n o t prevent s e n s i t i z a t i o n s i n c e sulfanilamide (which i s r e a d i l y absorbed and excreted) and s u l f a t h i a z o l e (which has t h e s h o r t e s t h a l f - l i f e of a l l sulfonamides) produce t h e l a r g e s t number of r e a c t i o n s . On t h e s u r f a c e , i t seems d i f f i c u l t t o r e c o n c i l e t h i s f a c t w i t h L e h r ' s view t h a t t h e incidence of s e n s i t i z a t i o n depends on the amount and c o n c e n t r a t i o n of t h e s u l f a drug t o which p a t i e n t s a r e exposed b u t w e s h a l l r e t u r n t o a p o s s i b l e explanation of t h i s discrepancy l a t e r on.
Several a u t h o r s have speculated on the r o l e of plasma p r o t e i n s i n t h e processing and f i n a l d i s p o s a l of drug&, and while i t has been suggested t h a t conjugation of drugs or of t h e i r m e t a b o l i t e s w i t h plasma p r o t e i n s might produce a n t i g e n i c compounds, t h i s tempting ypothesis has never been v e r i f i e d . On t h e o r e t i c a l grounds, N - a c e t y l a t e d or N1-conjugated s u l f a d e r i v a t i v e s , even i f bound t o albumin, should n o t b e expected t o become a n t i g e n i c determinants. Table I supports our b e l i e f t h a t p r o t e i n binding, per se, does not e x p l a i n s e n s i t i z a t i o n ; some sulfonamides which, l i k e s u l f i s o x a z o l e , are r e a d i l y bound t o albumin, cause few a l l e r g i c r e a c t i o n s . Parker has s t a t e d t h a t r e v e r s i b l e binding of a s i m p l e chemical t o protein, r e g a r d l e s s of degree, i s n o t r e l a t e d t o i t s a b i l i t y t o s e n s i t i z e 9 , b u t t h e p o s s i b i l i t y e x i s t s , of course, t h a t p r o t e i n binding m i g h t p r e v e n t s e n s i t i z a t i o n . S u l f a t h i a z o l e , however, which probably produces t h e h i g h e s t number of a l l e r g i c symtoms, is bound t o albumin a t twice the r a t e of s u l f a d i a z i n e (which i s innocuous) and a t seven times t h e rate of s u l f a nilamide which s e n s i t i z e s a s i g n i f i c a n t number of p a t i e n t s . By and l a r g e , we have no evidence t h a t r e v e r s i b l e binding of s u l f a drugs t o plasma albumin has e i t h e r a p o s i t i v e o r negat i v e e f f e c t on s e n s i t i z a t i o n .
Q
2 58 -
Sect. V- Topics in Biology
Tabachnick, Ed.
The renal clearance of sulfa drugs, on the other hand, might have some bearing on their sensitizing potential, but the connection is, at best, suggestive. Sulfanilamide is excreted by glomerular filtration, but some of the newer sulfonamides are reabsorbed by the renal tubules. Experimental findings suggest that tubular handling of sulfa drugs might correlate with the ability of the drug to diffuse from an aqueous into a lipid solvent. Tubular reabsorption creates a long half-life; this is true for sulfadimethoxine and sulfamethoxypyridazine. While sulfadimethoxine and sulfamethoxypyridazine have a comparatively low incidence of 'conventionalt immunological reactions, they are now known to give rise to a significant incidence of Stevens-Johnson syndrome which is thought to represent an immunological response. Research into its pathogenesis is complicated by the species specificity of the syndrome; like other phenomena which are caused by the biotransformation of drugs, it has no counterpart in experimental animals. Binding of drugs to plasma albumin is 'normal', just as $-acetylation or N1-conjugation with glucuronide must be considered 'normal' events which forestall the emergence of sensitizing metabolites. The low incidence of sensitization to drugs in general - considering the total number of potentially sensitizing compounds which are taken must mean that most drugs and their metabolites are handled with uncanny skill and efficiency. If sensitization does take place, it might not necessarily reflect an obligatory, built-into-the-drug formation of an antigenic determinant, but the 'abnormalt and faulty handling of a potentially innocuous metabolite by a deficient host.
-
As a result of the growing suspicion that the major (and usually well-known) metabolites of common drugs might not be the metabolites which cause sensitization, the search for minor metabolites has been resumed with considerable vigor in recent years. Williams had shown some years ago that although sulfanilamide is predominantly excreted unchanged or as an N4 acetylated compound, a small amount is not acetylated, but is oxidized to 3-hydroxy-sulfanilamide in amounts up to 10s of the total recovered metabolites. The same holds true for sulfathiazole and sulfadiazine and, conceivably, for other sulfa derivatives.lo Weinstein makes the interesting remark that sensitization is generally assumed to be caused by oxidized rather than by acetylated metabolites; and while he
-
Chap. 24
Drug Sensitization
S a m t e r , B e r r y m a n , Wiegand
259 -
does not give the source for this statement, there is good reason to believe that it is correct.ll Penicillin sensitivity presents a similar case in point: after extensive studies of possible breakdown products, it has lately been demonstrated that major sensitization might be attributed to minor contaminants.12 It is conceivable, in other words, that the formation of antigenic determinants indicates that the host has exhausted 'normal' metabolic pathways and has turned to pathways which produce 'haptens'. 'Normal' metabolic pathways in man may be inaccessable for a variety of reasons, e.g. a genetic absence of the appropriate enzymes, or their commitment elsewhere to cope with the simultaneous administration of drugs which compete for the same substrate.13a14,l-5 Or, conceivably, the administration of large doses of a single drug which is ordinarily handled in a predictable fashion by microsomal enzymes, may exceed even briefly, their capacity. With this possibility in mind, Lehr's views should be reexamined since it seems quite possible that a drug which rarely forms sensitizing metabolites might do so when uncommonly large amounts are given.
It has never been established, however, that the appearance of metabolites which can form co-valent bonds with macromolecules in vitro, must be followed by sensitization in vivo. It is possible that the 'biochemical integrity' of an individual does not end with the selection of innocuous metabolic pathways, but might also have access to unidentified 'mechanisms of detoxicatlon' which neutralize antigenic determinants before they can conjugate with homologous 'carriers'. The existence of such secondary means of protection is strongly suggested by a study which is frequently cited in support of the hypothesis that solubility is a primary prerequisite for sensitization. Sulzberger and his associates placed equivalent amounts of various sulfonamides on the base of an induced third-degree burn.16 Sulfanilamide produced reactions in 22s of the patients, sulfathiazole (which produces the highest incidence of sensitization if administered systemically) in only 7$, sulfadiazine in only 5$, but the soluble sodium salt of sulfadiazine in 57%. It seems to us that these findings do not necessarily indict solubility as a factor in sensitization, but rather indicate that the skin lacks a protective mechanism which is present if the same drugs - regardless of solubility are taken by mouth.
-
260 -
Sect. V
-
Topics i n Biology
Tabachnick, Ed.
The defenses of t h e h o s t a r e even more impressive i f he i s exposed t o a drug which, l i k e chloroquine, has a wide spectrum of r e a c t i v i t y i n v i t r o as w e l l as i n vivo. T h i s a n t i - m a l a r i a l and anti-amebic drug has been recommended f o r t h e treatment of d i s c o i d and systemic lupus erythematosus, of a u t o a e n s i t i v i t y t o DNA, of polymorphic l i g h t e r u p t i o n s , of rheumatoid a r t h r i t i s , of hypercalcemia, and even of pulmonary l e s i o n s i n s a r c o i d o s i s .I7 I n v i t r o s t u d i e s have demonstrated t h a t chloroquine i n h i b i t s m u l t i p l e enzyme s y s t e m s i n c l u d i n g t h e NADH - cytochrome C r e d u c t a s e system, t h a t i t binds t o melanin and DNA, t h a t i t s t a b i l i z e s lysosomes, t h a t it blocks t h e s u l f h y d r y l - d i s u l f i d e interchange, and t h a t , t o some degree, i t suppresses inflammation. I n view of t h i s impressive a r r a y of b i o l o g i c a c t i v i t i e s , i t seems remarkable t h a t chloroquine i s a s a f e drug i n t h a t only a small number of p a t i e n t s become s e n s i t i v e t o it. The i n t r i c a t e system which channels drugs through t h e
v a r i o u s t r a n s f o r m a t i o n s involved i n a b s o r p t i o n , c i r c u l a t o r y t r a n s p o r t , metabolic handling and e x c r e t i o n m u s t be endowed w i t h c e r t a i n safeguards which can prevent t h e development o f a n t i g e n i c determinants, o r t h e conjugation of t h e a n t i g e n i c determinant w i t h a macromolecular c a r r i e r , even though t h e drug o r i t s m e t a b o l i t e s might f u l f i l l one o r more of t h e s t r u c t u r a l requirements f o r s e n s i t i z a t i o n . The a d a p t i o n of man t o chemical a s s a u l t i s q u i t e e x t r a ordinary. It i s i n t r i g u i n g t h a t we are n o t more v u l n e r a b l e than w e a r e t o t h e continued c o n f r o n t a t i o n w i t h new chemicals which challenge our microsomal enzymes. We have been preoccupied, r i g h t l y , w i t h t h e s t r u c t u r a l p o t e n t i a l of drugs and m e t a b o l i t e s t o induce s e n s i t i z a t i o n . Possibly a more productive approach would evolve from t u r n i n g o u r a t t e n t i o n t o t h e h o s t t o analyze h i s means f o r preventing s e n s i t i z a t i o n when assessment of i n v i t r o c h a r a c t e r i s t i c s of t h e drug i n d i c a t e t h a t s e n s i t i z a t i o n should occur.
Chap. 2 4
Drug Sensitization
% excreted as * t50% protein, hrs. binding N1m c hangec N4at 0.4 acety' g lucuron molar conc'n. % of
Drug
-
Su1fani1 amide
12
-
Sulfathiazole
77
-
Su lfadiazine
45
17
9
30-80
20-60
4
30
20-60 -
% of
% of
sensitivity reactions after systemic administr.
sensitivity reactions after topical application
**
12
**
19
22
-k-k
Sodium Sulfadiazine
-
60
30 -
10
.6
5
57
-
-
Su 1fadimeth-
***
oxine (Madr ibon)
98
35
7
15
Sulfisoxazole (Gantrisin)
90
-
6
70
30 -
Su1famethoxypyridazine (Kynex 1
91
40
30
60
Table I
26 1 -
S a m t e r , B e r r y m a n , Wiegand
78
3 6
*** 10
8
I
Pharmacological data (approximate) and reported incidence of sensitization for some commonly used sulfonamides. *assuming normal renal function. *from 5-10% of the drug is oxidized and excreted as 3-hydroxysulfanilamide 3-hydroxysulfathiazole, 4'-hydroxysulfadiazine, respectively. **the recognition that "long-acting" sulfonamides can cause StevensJohnson syndrome is of recent origin and exact figures of the incidence are not yet available.
Sect. V
-
Topics in Biology
Tabachnick, Ed.
Bib 1iography 1. Brodie, B. B. and Hogben, C. A. M., J. Pharm., 9, 345 (1957) 2. Brodie, B. B.: Absorption and Distribution of Drugs, London (1964 3. Davies, G. E., A Symposium (Rosenheim, M. L. Moulton, editors), Oxford, 149, (1958). 4. Bhger, P., Diller, W., Fuhr, J., and KrLger-Thiemer, E., Arzneim.-Forsch. 11, 247-255 (1961). 5. RiEder, J., Arzneim.-Forsch. 13, 81-103, (1963). 6. Kruger-Thiemer, E. and Bunger, P., Proc. of the European Society for the Study of Drug Toxicity, V I , (1965), International Congress Series No. 97, 185-207. 7. Lehr, D., Ann. N. Y. Acad. of Sci. 69: 417 (1957). 8. Bennhold, H., Dtsch. Med. Wschr. 76: 1485, (1951). 9. Parker, C. W., in: Immunological Diseases", 663-681, Boston (Little, Brown 6 Co.), (1965). 10. Williams, R. T., Detoxication Mechanisms (John Wiley & Sons), New York (1959). 11. Weinstein, L., in: The Pharmacological Basis of Therapeutics, 3rd. ed. , 1151, (Macmillan), (1965). 12. Voss, H. E., Redmond, A. P., and Levine, B. B., J.A.M.A. 196: 679, (1966). 13. Dixon, R. L., Shultice, R. W. and Fouts, J. R., Proc. S o c . Exp. Biol. Med. 103, 333 (1960). 14. Maickel, R., Gordon Conferences on Nutrition (1961). 15. Samter, M. and Berryman, G., Allergology, Pergamon Press (1962). 16. Sulzberger, M. B., Kanof, A., Baer, R. L. and Lowenberg, C., J. Allergy 18: 92, 1947. 17. Sams, W. M., Jr., Mayo Clin. Proc. 42: 300-309 (1967).
26 3 -
Chapter 25. Factors Affecting Adrenal Steroidogenesis Herbert Shepparc?, Research Dept., ClBA Pharmaceutical Co., Summit, N.J. Introduction. The work to be reviewed will concern the mechanism and pathways of synthesis of adrenal corticosteroids as they may be affected by the natural hormone, ACm, and various chemical agents. For the purpose of orientation an outline of the pathways of synthesis is included below. The s o l i d arrows indicate the need for 02 and reduced nicotinamide adenine dinucleotide phosphate (NADPH) while the double arrows suggest a need for the oxidized forms Cholesterol (Chol) (NADP or NAD). Reference to the steroid listed be1 low will be made in the text through the abbrevia2W-OH Chol tions shown in parentheses. In addition, radio1 active compounds will be starred. 20,22-diOH Chol
' L
Pregnenolone (Preg) 21
11-OH P j 1 1 , 2 1 - d i O H P (B)+ll-dehydro
2 7 -+ 21-OH P (DOC)
L
YH3
c=o
L
B (A)
11,18,21-triOH P (18-OH B)+11,21diOH-18-01 P (Aldo)
7
18-OH P--$ 18,214iOH P (18-OH WC) 11,17,21-triOH P (F)+ll-dehydro
F (E)
7 l7-OH P +17,21-diOH
P (S)
o=LL'
Progesterone (P)
Pathways of Synthesis. Sulfated steroids are produced by human adrenals from both P+l and 20cr-OH-Cho12. The failure of chicken adrenals to use Chol*3 is overcome by solubilizing high specific activity material with Tween 804. The failure of 2Oa-OH,22-keto-Chol to trap the radioactivity from Chol* mediates against its being an obligatory intermediate?. Mitochondria1 fractions from the adrenals of several species contain enzymes necessary for steroid production. These include a solubilizable Chol side chain splitting complex6, a non-soluble cytochrome P-4507, 18hydroxylase and 18-01dehydrogenase from sheep8 and bullfrog9 adrenals and enzymes from the guinea pig adrenal which 11- and 2l-hydroxylate,reduce ring A and remove side chain of Sl0. The lI$3-hydroxylase in adrenal homogenates of the guinea piglo is mximally stimulated by Krebs-cycle acids in the absence of NADPH while that of the ratll is stimulated by both. The response in the rat varies with the Ca concentration suggesting a partial dependence on the degree of mitochondria1 swelling. Minced rat adrenals convert P* to WC and then to B and 18-OH WCl2. High concentrations of NADPH inhibit 21- but stim-
264
Sect.
V - Topics in Biology
Tabachnick, Ed.
ulate 1lp-hydroxylations of F+ in rat adrenal homogenates such that 11-OH P ts the major producti3. The 18-OH DOC area on paper chromatograms may be contaminated with allotpahydro B which is produced in smaller amounts in the presence of ACT314. Another complication is that during a preincubation period, enzymes are lost from the gland which can convert Preg* to P and can hydroxylate the P in positions 17,U and Z!115. Glucose-6-phosphate (G6P) dehydrogenase activity is also present. Rat adrenal small particles contain a A5-3 ketosteroid isomerase for which NAD or NADH but not NADP o r NADPH serve as activators but not electron donors or acceptors16. Without ACTH, the adrenal of the Mongolian gerbil converts P* to DOC, 18-OH DOC and E in vitrol7. Animals killed with nembutal instead of ether, produce $ 3 -but the F and 19,21-diOH P seen in adrenal venous blood19 is not detectable. The European eel converts P* to 17-OH P, s, F and E20. ACTII stimulates the steroid production of the adrenals of turtle and snake to a lesser degree than that of the bullfrog1. Aldo Synthesis. Bullfrog adrenal homogenates synthesizing Aldo at the high rate of 250 pg/g/hr. require NADPH, fumarate and Mg9 which can be replaced by Ca or Mn. Phosphate, ATP, Na and K are not required. Rat and bovine homogenates contain an inhibitor of Aldo synthesis. The production of 18-OH B and Aldo by rat adrenal quarters increases linearly for 20 hours but, if the animals drink 1% NaCl for 8 days, production plateaus after 2 hours22. The accumulation of B and 18-OH DOC plateaus after 4 hours. Adrenal sections from Na-deficient rats convert B*, DOC*, P* and Preg* to Aldo and B23. Angiotensin 11, NH4 and ACTH increase production from endogenous substrates while NADPG6P stimulate conversion of exogenous substrates as well. Angiotensin I1 and NH4 stimulate only Aldo production while the other factors stimulate B + Aldo. These agents are believed to act between Chol and Preg. With the turtle adrenal, ACTR stimulates Aldo production 250q6. Rat adrenal regeneration following enucleation or ACTH results in a depressed ability t o produce Aldo and 8-OH B and an increased ability to form B and 18-OH Doc from P* and Doc*2 Adrenal homogenates of sheep, cow and guinea pig show a decreasing ability to convert P* or Doc* to Aldo and l8-OH B8. The ratio of 18-OH B/Aldo is 2 for cow and guinea pig while with sheep homogenates values of 2, 4 and 9 are seen with P*, Doc* and B* respectively. The conversion of B to Aldo requires NADPH but the presence of NADP or NAD promotes 11-dehydrogenation with the formation of 18-OH A. Sonication failed to solubilize these enzymes. They are stimulated by Ca but inhibited by Cu, Zn, Co, Hg, Fe ana
r4 .
lrln
.
Analysis of dog adrenal vein blood shows higher secretory rates for Aldo, B and F in animals on a low Na diet by factors of 8.6, 14.1 and 417, respectively25. Incubation of such adrenals in the absence of added substrate, kave-rzr, results ir a %vo-fold increase, in aldo, and aecrease in 9 with no effect on F production. Because of this uifference between the in vivo 2nd in vitro responses, as well as changes in F/B ratios it is -difficult to accept the proposal that Na deficiency is affecting the B to Aldo pathway. While it is shown that twice as much B* is converted to Aldo by Na deficient adrenals, the production of half the amount of B tends to increase the net specific activity of B. The amount of label in
Chap. 25
Adrenal Steroidogenesis
Sheppard
265 -
Aldo will double even though the same number of molecules of B are converted. Thus the conversion of B to .41do will not actually be stimulated. In man, Na depletion is thought to act at some point prior to DOC such that the precursors are increased26. It is cautioned that since B production is under control of both Aldo and F stimulating factors, its measurement gives a false picture of F production. Caution is required when dexamethasone is used to shut off F associated production of B since it is reported to reduce Aldo production as wel127. Some interactions between the F and Aldo secreting systems must exist, since feeding a high Na diet suppresses Aldo but stimulates F secretion28. Angiotensin I1 in vitro fails to stimulate Aldo production by rat29 and bovine30 adrenal sections. Administration for 3 days, in the rat, had the same negative effect3l. With bovine adrenal slices, angiotensin I1 reduced acetate* incorporation in P and l 7 - O H P but increased it into all other steroids suggesting a site of action prior to the formation of Chol3O. Thus the site of action of both Na deficiency and angiotensin I1 remains elusive. While Na deficiency will increase the juxtsglomerular index (JGI) of the kidney and will result in increased Aldo secretion, division of the common bile duct also increases the JGI but does not necessarily result in ascites or an elevated Aldo secretiod2. Surgical relief o f an otherwise intractable hyperaldosteronism resulting from severe hepatic outflow obstruction is achieved by a side-to-side portacaval shunt33. Inhibitors of Protein and RNA Synthesis. A review of the action of ACT€134 in 1965 points out that the obligatory requirements for RNA or protein synthesis is still open to question. The following studies do little to correct the situation. Puromycin and cycloheximide inhibit both the incorporation of amino acids* into protein and steroidogenesis by rat in vit1-035~36. NADPtG6P reverses the inhibition of Aldo proadrenals, -duction but not that of leucine* incorporation35. These agents act similarly in vivo and in addition cause hepatic but not adrenal glycogenolysis36. The suggestion that glycogenolysis may, therefore, not be involved in steroidogenesis is supported by the finding that the adrenal responds even better to ACTH following a pre-incubation period that results in a loss of glyc0gen3~. Whfle cycloheximide and puromycin are thought to block the AC"H stimulated protein synthesis, no stimulation by ACTH is demonstrated. The problem is further complicated by the reported inhibition of glycine* incorporation by cyclic AMP, ACTH and NADPG6P, all of which stiaulate steroidogenesis by rat adrenal quarters37. The addition of theophylline, an inhibitor of cyclic AMP phosphorylase, further depresses glycine* incorporation without affecting steroid production. The suggestion is made that with theophylline, unlike with ACTK, decreased glycinex incorporation now represents decreased steroidogenesis. Fortuitously, this balances the stimulation which is expected fro= an inhibition of cyclic AMP phosphorylase and no change in steroid production need occur. m i s is unacceptable in the absence of any experimental data. A recent study shows that adrenals of 8 hour hypophysectomized (hypoxed) rats secrete less steroids but have unchanged uridine* incorporating abilit~3~.Actinomysin D inhibits uridine* and amino acid* incorporation in the absence of ACTH but has no effect on steroid secretion in the
266 -
Sect. V
-
Topics in Biology
Tabachnick, Ed.
presence of ACTH. It is concluded that the ACTH induced formation of a steroid-regulating protein (not demonstrated) does not require new RNA formation but can be directed by RNA which is stable for 8 hours. However, such data could mean that neither RNA nor protein synthesis is involved in the steroidogenic effect of ACTH.
.
Metyrapone (M) 2-methyl-lj2-bis-( 3-pyridyl)-1-propanone, continues to be used clinically for determining the pituitary's ability to secrete ACTH. The adrenal response to the drug as measured by the secretion of F and S is found to depend on the pituitary reserve of ACTH and the degree of dose-dependent inhibition of 1l@-hydroxylase39. The failure to include the increased secretion of DOC leads to a low value for the inhibition of the enzyme. The varied M response seen in liver disease may result from altered metabolism of the drug40. NADPH does not reverse the M i ibited conversion of P* to B, 18-OH B and Aldo by mouse adrenal quarters . Neither 2l-hydroxylation, ring A or 20-keto reduction is inhibited by M42. Acutely hypoxed rats secrete more blue tetrazolium reducinf (BT+) steroids following M suggesting a direct stimulation of the adrenal 3. However, rats secrete a BT- steroid, 18-OH DOC, and thus inhibition of 11- and 18hydroxylations by M could result in an amount of BT+ WC equal to B +18-0H Doc. While total BT+ material would increase, the total amount of steroid could be the same and a direct effect on the adrenal need not be considered. Bovine adrenal ices produce less 11-oxysteroids and more S and DCC in the presence of M The data shows that the increase in DOC and S is much less than the decrease in 11-oxygenated steroids at the concentrations used, suggesting an inhibition of 21-hydroxylation. Inhibition by M of 11and 18-hydroxylations in rat adrenal mitochondria appears to be linked to the utilization of Krebs-cycle acids and may act mainly on the c ochrome P-450 system rather than the classical electron transport system 5 . Prolonged treatment of dogs with M results in elevated blood pressure, hypokalemia, polyuria and l7-KS excretion in some animals which may have resulted from increased S and Doc secretion46. Adrenal hyperplasia in half of the dogs resembles that seen in the hypertensive form of congenital adrenal hyperplasia. Chronic treatment of rats with M and amphenone B causes decreased weight gain and plasma B levels but increased adrenal weights47. Peculiarly, injecting only 0.001 pg of B increases ACTH activity of plasma. With increasing amounts of B, the kCTH content rises further and then decreases even if median eminance lesions were made 2 days earlier. Thus, small amounts of B may stimulate the anterior pituitary directly.
91
ti .
T
SKF-l2l85. 2-(p-aminophenyl)-2-phenylethylamine inhibits B production in vitro by the rat and F production in vitro and in vivo by the guinea pig a d r a . Signs of adrenal insufficiency are produced in rats. Clinical studies suggest that like M, the drug is partially an 11- and 18-hydroxylase inhibitor49, 5O. Glutarimide Derivatives. Glutethimide (a-ethyl-a-phenylglutarimide as well as its 0-, m- and p-EH3 and p-OH phenyl derivatives are inactive Dehydrogenation of the ring, reduction of one or both keto-groups or s u b stitution of S for 0 yields no active compounds. The N-amino, o-amino-
Chap. 25
Adrenal Steroidogene sis
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phenyl, and p-amino phenyl (aminoglutethimide) derivatives as well as 3biphenyl-6-keto piperidine and 3-biphenyl piperidine are found to be total blockers. An 11-hydroxylase inhibitor, a-(p-chloropheny1)-a-(2-pyridyl) glutarimide is also reported. Aminoglutethimide (AG) blocked the ACTH response, caused adrenal hypertrophy in rats and normalized plasma and urine corticosteroid levels in 2 patients with Cushingls syndrome5*. Its use as an anticonvulsant drug in 2 children produced signs of adrenal insufficiency53. The secretion of F and B in puppies fell with no rise in S or Doc and it was concluded that AG acts between Chol and Preg54.Adrenal, thyroid and ovarian weights increased in normal but not hypoxed rats given AG55. During 182 days oT treatment all clinical and biochemical signs of Cushing's syndrome disappeared and adrenal metastasis appeared arrested%. Steroids. A large number of steroids including adrenal corticosteroids, androgens, estrogens and synthetics were found to inhibit a number of hydroxylations carried out by bovine adrenal homogenates.57. However, the use of amounts of steroids exceeding their solubilities introduces an element of doubt as to the validity of the interpretations since some of the effects may result from an interaction between a solid phase and enzymes58. Norethynodrel, 174-ethinyl-17p-h droxy-5( lO)-estrene-3-0ne, increases Plasma and adrenal B levels deadrenal weights in intact female rats5 crease at the time of day when values are normally highest. Clomiphene increases output of 17-oxysteroids in a patient with galactorrhea60. Cyanotrimethylandrostenolone,2a-cyano-4,4,17a-trimethyl-17$-OH-5-androstene-3one, causes adrenal hypertrophy, a fall in adrenal venous i3 of male rats and inhibition of 3-hydroxysteroid dehydrogenase61. Norethandrolone, 17a-ethyl-17p-OH-4-norandrostene-3-one, stimulates the production of B by adrenals of castrated rats and increases pituitary ACTH content62. This androgen partially reverses the E induced suppression of B production but not of the adrenal response to stressG2. Testosterone, androstenedione, DHEA, estrone and estradiol has no effect on conversion of B to 18-OH B and Aldo by sheep adrenal mitochondria8.
5.
Miscellaneous. Other total blockers of adrenal hydroxylations include 1,2- and 1,4-naphthoq~inones5~.Inhibitors of 17-, 18- and 19hydroxylases include 1- and 4-(5) but not 2-benzylimidazoles51. Inactive compounds include imidazolines, benzimidazolines, diphenylhydantoin and various barbiturates51. Adrenal necrosis caused by 2-dimethylbenzanthracene (IMBA) is blocked by M or impaired liver function63 while that brought on b its metabolite, 7-hydroxymethyl methylbenzanthracene is blocked only by Mg4 This metabolite is 2-3 times more active, less toxic and spares the zona glomerulosa Unlike the D@A, R0-1-8307, N-formyl-chitosan polysulfinic acid, (z.g. ). having heparin-like activjty, reduces the width of z.g. but not the other zones of the rat adrenal65. It reduces A o secretion in cases of primary aldosteronism and blocks 18-hydroxylationi2. A heparin antagonist, hexadimethrine bromide, causes adrenal and pituitary necrosis in the rat but not the dog despite a fall in adrenal blood flow and 17-OH steroid secretion@.
.
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Sect. V - Topics in Biology
Tabachnick, Ed.
A.
Stimulation of adrenal function-by N,N-dimethyl-p- m-tolylazo) aniline appears necessary for the production of liver toxicit Methylcholanthrene increases plasma half-life of B without affecting its volume of distribution suggesting a decreased rate of metabolism@. However, when the pool size is calculated it can be seen that the turnover of B is only slightly reduced, if at all. Phenylbutazone increases the volume of distribution with no change in half-life but similar calculations show that the turnover of B is the same as in cold exposure. It is suggested that the increased turnover in cold stress results only from increased synthesis. However, the use of steady state kinetics requires that synthesis and degradation be equal and thus both would increase Cortisol secretion by isolated adrenal pouches in hypoxed dogs was stimulated by cyclic AMP, vasopressin and ACTH7O. However, epinephrine and norepinephrine, which stimulate formation of cyclic AMP in fat pads, dichloroisoproterenol, which inhibits adenyl cyclase, or dihydroergotamine, an inhibitor of action of cyclic AMP in the liver, failed to have any effect. The -SH binding agents, diethyldithiocarbamate, p-chloromercuribenzoic acid, iodoacetic acid, formamidine acetate and N-ethyl-maleimide inOf these, only formamidine acetate fails to hibit 18-hydroxylation of €@. inhibit 11-dehydrogenase. Of the 17-hydroxylase inhibitors tested, Su-9055 inhibits 18-hydroxylase, SU-8000acts on 18-01dehydrogenase and SU-10603 is inactive with sheep adrenal homogenates8. Since Su-955 and Su-8000 were tested on different homogenates showing appreciable variation in 18OH B/Aldo ratios, the conclusion that the two drugs differ in action is open to question. Stimulation of 1l.p-hydroxylase activity by Krebs-cycle acids is inhibited by CN and Amytal8. With rat adrenal homogenates, Amytal is not active in presence of isocitrate or Ca and the CN effect is reversed by isocitrate + NADF'H7l. Oligomycin is inactive but Antimycin A, ferricyanide and dinitrophenol act like Amytal. This supports the concept of a link between the classical electron transfer chain and the P-450 containing hydroxylating system. Rhythm and Stress. An excellent review of Circadian rhythm includes a section dealing with that of adrenal cortical secretions72. In the rat, the plasma and adrenal B are higher in the P.M. and F implants in the median eminance, midbrain reticular formation and ventral hippocampus reduced plasma and adrenal B. However, only the median eminance implant reduced the A.M. adrenal B and adrenal weight73. It is felt that the median eminance regulates the secretion of the corticotrophin releasing factor (CRF) while the other areas in some way modulate this effect. Humans excrete more 17-OHCS in the A.M. and in men the increment associated with "sustained effective distress" was greatest at this timeT4. The increment seen with women, however, is greatest during the P.M. trough of the diurnal curve. Pathological emotional stress and adrenocortical activity is reviewed and it is concluded that the psychological variable correlating with increased secretion is loss of Ireo defense strength"75. Stress increased the CRF activity of rat plasma7t f but this could be an artefact since CRF was tested in rats with implanted pituitary tumors while A C m was tested
Chap. 25
Adrenal Steroidogenesis
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269 -
in normals. If the adrenals were larger in the tumor rats the increment in the ACTH response could be mistaken for CRF activity. Rats with diabetes insipidus (DI) responded to stress with a smaller increase in plasma B and this went uncorrected after several weeks of vasopressin treatment, despite the improvement of ~177. Treatment of rats with the histamine depleter, 48/80, blocked the adrenal response to various forms of stress but not to histamineT8. This suggests some role for histamine in the stress response and in this regard it should be noted that anaphylactic shock in dogs is accompanied by a stimulation of 17-OHCS secretion79. A neonatal stress non-responsive periods0 does not exist when plasm E is measured in place of adrenal B8l, B2. Action of ACTH. ACTH given in 4 injections to rats decreases adrenal lipids and Chol esters but increases phosphatides and arachidonic acid83. Bovine adrenal slices use more added Chol* but not P* in the presence of ACTH84. The conclusion that a pool of 21-desoxypregnanes is released by ACTH for hydroxylation is questionable in the absence of data on the time course of production *ofsteroids. Histochemical analysis of enzymes in rat adrenal sections demonstrated that NADPH-dichlorophenolindophenol reductase of the zona fasciculata-reticularis (z.f-r.) is stimulated by ACTH whereas NADPH or NADH quinone reductase, N.ADPH and NADH oxidases or NADPH-NAD transhydrogenases are not85. In tissue culture, cells of the rat adrenal cortex with mitochondria of the type found in the z.g. do not respond to ACTH while those of the z. intermedia show mitochondria1 changes to the vesicular types seen in the z.f-r.86. The tubular and vesicular forms of the endoplasmic reticul u m also increase. A large number of dehydrogenases are shown to be present but ATP-ase as well as alkaline and acid phosphatase are absent. Chromatin condensation along the nuclear membrane suggest that ACTH might effect transformation of z.g. cells to those of the z.f-r. by action at the nuclear or gene level. Cloned mouse adrenal cortex tumor cells respond to AC% with an increased output of steroids which is independent of the growth phase87. Jithin 5 minutes the cells retract from tie surface of the vessel and from each other and within 1 hour a rounded-up morphology is seen. This cell line is unable to hydroxylate position 21 but has a high ability to reduce the 20-keto gr up. A synthetic corticotrophin stimulates B production by rat adrenal sections88 and has a half-life in nan o 32 minutes@. Little or no activity is seen with the p1-l0 and B11-29 fra ents88. Alphamelanocyte hormone has only weak ACTH-like activit$e 9O. A synthetic 6 1-25 corticotrophin with D-serine, L-norleucine and L-valine-amide at positions 1, 4 and 25 respectively was preparedgl and reported to be 6 times as active as the natural and synthetic @1-24preparationsg2. IIFFSFENCES 1. G. P. Klein and C. J. P. Giroud, Can. J. Biochem. 44, 1005 (1966) 2. K. Shimizu, J. Biochem. (Tokyo) 59, 430 (1966) 3. T. Sandor, J. Lamoureaux and A. Lanthier, Steroids 6, 143 (1965)
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4.
5. 6.
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T o p i c s i n Biology
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P. F. H a l l and S. B. Koritz, Endocrinology 79, 652 (1966) G. Constantopoulos, A. Carpenter, P. S. S a t z and T. T. Tchen, Biochemistry 5, 1650 (1966) P. Setok, G. Eonstantopoillos and T. T. Tchen, Biochemistry 2, 1646
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5-Hydroxytryptamine and the C e n t r a l Nervous System Chapter 26. Roberto Levi and J a c k P e t e r Green, Department of Pharmacology., Cornell University Medical College, New Y o r k , N. Y . 1 0 0 2 1 Much of the extensive w o r k that has been done on 5-hydroxytrypta m i n e ( H T ; serotonin) s i n c e its isolation and identification twenty y e a r s ago h a s been d i r e c t e d t o uncovering its possible function i n n e u r a l activity. A s no s h o r t review can include r e f e r e n c e s to all the n u m e r o u s contributions, the a u t h o r s have t r i e d t o s e l e c t t h o s e r e f e r e n c e s that a r e r e c e n t and include a significant bibliography. N o a t t e m p t h a s b e e n m a d e t o designate p r i o r i t i e s f o r the observations. Two booksl, 2 and a s y m posium3 scheduled f o r publication in 1968 provide full r e f e r e n c e s and detailed d i s c u s s i o n s of all a s p e c t s of t h e subject.
-
Distribution in the c e n t r a l nervous s y s t e m (CNS) HT, which w a s f i r s t detected in m a m m a l i a n b r a i n by Twarog and P a g e 4 and Amin e t _a1 * 2 o c c u r s in the CNS of m a n y v e r t e b r a t e , m o r e p r i m i t i v e s p e c i e s having a relatively g r e a t e r concentration. The a m i n e i s concentrated in the phylogenetically old p a r t s of the b r a i n 5 , which a r e connected with the autonomic nervous s y s t e m o r with the r e t i c u l a r activating formation. Thus, the l a r g e s t amounts of HT a r e p r e s e n t in the hypothalamus and midbrain, while m u c h s m a l l e r amounts a r e found i n the c e r e b r a l cortex, c e r e b e l l u m and white m a t t e r 6 . After i n t r a v e n t r i c u l a r injection, t r i t i a t e d HT w a s taken up by a r e a s r i c h in endogenous HT7, 8. The u s e of histof l u o r e s c e n c e m i c r o s c o p y in combination with d r u g s allowed the visualization of c e n t r a l s e r o t o n e r g i c neurons in t h e i r e n t i r e extension9. Axotomy combined with histofluorescence m i c r o s c o p y h a s shown that HT rapidly a c c u m u l a t e s in the portion of the axons immediately proxim a l t o the lesion, a n observation suggesting that HT i s synthesized in the c e l l bodies and t r a n s p o r t e d down the axons9-11.
’
Maintenance of HT (and norepinephrine a l s o ) in the r a t b r a i n i s dependent upon the integrity of the m e d i a l f o r e b r a i n bundle within the l a t e r a l hypothalamusl2s 13: When the m e d i a l f o r e b r a i n bundle d e g e n e r a t e s a s a consequence of a l e s i o n produced in the l a t e r a l hypothalamus, HT is depleted in the telencephalon i p s i l a t e r a l t o t h e l e s i o n in the r a t and cat. Concomitant with depletion of HT in t h i s region i s a d e c r e a s e in the activity of L - a r o m a t i c amino acid decarboxylase, the enzyme that f o r m s HT f r o m its p r e c u r s o r l 4 . Specific l e s i o n s can selectively affect monoamine l e v e l s : l e s i o n s in the c e n t r a l g r a y a r e a and the septum lower the level of HT in the telencephalon without affecting the level of
27 4 -
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norepinephrine, w h e r e a s a n opposite effect follows ventrolat_eral tegm e n t a l l e s i o n s l 2 . Such studies have mapped out the c e n t r a l s e r o t o n e r g i c system. The ascending s e r o t o n e r g i c neurons have t h e i r c e l l bodies located m a i n l y in the m e s e n c e p h a l i c nuclei and t h e i r axons r u n u n c r o s s e d , principally in the m e d i a l f o r e b r a i n bundle to the l i m b i c f o r e b r a i n s t r u c t u r e s and the hypothalamus15. The p r e s e n c e of descending HT neurons h a s a l s o been d e s c r i b e d i n the m a m m a l i a n spinal c o r d ; the c e l l bodies a r e located in s u p r a s p i n a l c e n t e r s and the f i b e r s descend in the l a t e r a l and a n t e r i o r funiculi t o end i n the g r a y matte^-9, 16. Differential and density gradient centrifugation of m a m m a l i a n b r a i n showed that m o s t of the HT i s a s s o c i a t e d with p a r t i c u l a t e m a t e r i a l , e s p e c i a l l y a f r a c t i o n containing pinched-off n e r v e endingsl7-21. Disruption of t h e n e r v e ending p a r t i c l e s by ultrasound22 o r by osmotic shock yielded a f r a c t i o n that contains v e s i c l e s like those s e e n at the synaptic junctions by e l e c t r o n microscopy. HT, differing f r o m n o r epinephrine, does not s e e m to b e p r e s e n t p r i m a r i l y in the v e s i c l e f r a c tion209 22a23, p e r h a p s b e c a u s e it l e a k s out of the v e s i c l e s during disruption of the n e r v e endings24. The uptake of HT by p a r t i c u l a t e f r a c tions of brain25-30 is dependent upon concentration of the amine2bY27, 2 9 ~ 3 0and upon temperature27-29, and w a s not s a t u r a b l e with a high concentration of HTZ79 2 9 a 30. Complexes between HT and o t h e r bioc h e m i c a l s have been review ed21. Biosynthesis - HT is synthesized in b r a i n f r o m the d i e t a r y amino acid L-tryptophan ( T P ) , with 5-hydroxytryptophan ( H T P ) a s a n i n t e r m e d i a t e . T P is actively and s t e r e o s p e c i f i c a l l y t r a n s p o r t e d into b r a i n 3 I . I n c r e a s i n g the intake of T P can i n c r e a s e the b r a i n l e v e l s of HT32-35. Phenylalanine and leucine d e c r e a s e t h e s e levels36, 37 p e r h a p s by inhibiting t r a n s p o r t of T P into the synaptosomes (Lovenberg3). F o r m a t i o n of H T P f r o m T P , which is t h e rate-limiting s t e p in the f o r m a tion of HT, i s catalyzed by a hydroxylase specific f o r T P and requiring NADPH, a reduced pteridine, 2-mercaptoethanol and probably f e r r o u s ion353 38-41. The hydroxylation by the pineal enzyme i s inhibited by norepinephrine , a - m e thyldopa 3 , 4 - dihy d r oxy - n- p r o p ylac et a m i d e , and L-phenylalanine (Lovenberg, e t al. 42). The inhibition of the hydroxylase and the reduction of HT l e v e l s by a - n -- p r o p y l a c e t a m i d e a r e 44. A drug that a p p e a r s t o inhibit specifically tryptophan not s p e c i f i c 4 3 ~ hydroxylase and t o deplete b r a i n HT in m o s t s p e c i e s without affecting 419 429 3 . But the l e v e l s of catecholamines is p-~hlorophenylalanine~~. in m a n the effects of t h i s d r u g a r e not c l e a r l y a t t r i b u t a b l e solely to depletion of HT46. The decarboxylation of H T P t o form HT is c a r r i e d out by a pyridoxal-dependent, non- specific L-amino acid decarboxylase47-52
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the distribution of which roughly p a r a l l e l s the content of HT in b r a i n 5 3 ~6. L o s s of enzyme activity a f t e r l a t e r a l hypothalamic l e s i o n s o c c u r s i n the s a m e a r e a s of b r a i n that show a d e c r e a s e in HT a f t e r t h e s e l e s i o n s , probably as a r e s u l t of degeneration of amine-producing n e u r o n s l 4 . The decarboxylase i s found in the soluble portion of the cell69 24. Inh i b i t o r s of this non- specific enzyme have b e e n d e s c r i b e d , the m o s t extensively studied being a-methyldihydroxyphenylalanine54. Disposition - It is p o s s i b l e that one m e c h a n i s m f o r the disposition of the endogenously produced a m i n e i s by diffusion, which could b e followed by re-uptake by n e r v e endings ( o r by o t h e r m a t e r i a l i n t i s s u e s ) a s h a s been shown with norepinephrine. But as yet t h e r e i s no evidence f o r such a cycle f o r HT, although, a s noted above, b r a i n and its p a r t i c ulate f r a c t i o n s have the capacity f o r uptake. A m a i n catabolic pathway f o r HT i s oxidative deamination by monoamine oxidase t o f o r m 5-hydroxyindoleacetaldehyde, m o s t of which i s converted to 5-hydroxyindolea c e t i c a c i d (HIAA) by aldehyde dehydrogenase and N A D 5 5 ~ 5 6 ;a r e l a tively s m a l l portion is reduced to 5-hydroxytryptophol b y alcohol dehydrogenase and NADH57, 58. Monoamine oxidase, which, like aldehyde dehydrogenase56, is a s s o c i a t e d with t h e mitochondria59, i s found throughout the b r a i n , with highest activity in the hypothalamus6. L e s i o n s of the m e d i a l f o r e b r a i n bundle, which produce a localized f a l l in b r a i n HT and HTP-decarboxylase a c t i v i t y l 4 , a l s o c a u s e a fall in HIAA in the s a m e a r e a s 6 * . S i m i l a r l y , section of the t h o r a c i c spinal c o r d produces a fall in HT and HIAA caudal to the l e s i o n with complete disappearance of both the a m i n e and the metabolite6I. It is possible that s o m e of the HIAA i n b r a i n d e r i v e s f r o m t r a n s a m i n a t i o n of H T P , followed by oxidation of the 5-hydroxyindole pyruvic a c i d , but a l m o s t c e r t a i n l y m o s t of the HJAA c o m e s f r o m HT. Other catabolic pathways f o r HT e x i s t in brain2, including acetylation of the p r i m a r y amino group. In the pineal body, the acetylation of the amino group i s followed by methylation of the phenolic hydroxyl group t o f o r m melatonin62; the methylating enzyme h a s not been found in any o t h e r m a m m a l i a n t i s s u e examined. Also uniquely p r e s e n t i n pineal body a r e 5-methoxytryptophol h 3 and 5-methoxyindole a c e t i c acid64. The hydroxyindole-0methylt ransf e r a s e r equir e s S- adeno sylmethionine62. Among othe r postulated catabolites of HT a r e hallucinogenic h a r m a l a n - l i k e compounds ( r e s u l t i n g f r o m cyclization of the side-chain) and bufotenine65. The p r e s e n c e of the l a t t e r i n u r i n e h a s been disputed66, 67, and i t s p r e s e n c e in b r a i n not demonstrated. Numerous inhibitors of monoamine oxidase have been studied, many in man2. T h e i r effects cannot be unambiguously attributed to a n elevation of HT, b e c a u s e they concomitantly elevate catecholamines. Ingestion of ethanol diminishes the e x c r e t i o n of HIAA and e l e v a t e s that
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of 5-hydroxytryptophol (and its conjugates), p r e s u m a b l y due t o the effect of ethanol in i n c r e a s i n g NADH r e l a t i v e t o NAD68, 69. The t u r n o v e r r a t e of HT in b r a i n , e s t i m a t e d by m e a s u r i n g the t i m e r e q u i r e d t o i n c r e a s e the concentration of HT i n b r a i n by 50 p e r cent, is about 10 t o 2 0 minutes70. M e a s u r e m e n t of the amount of HIAA f o r m e d f r o m HT yielded a half-life of n e a r l y 40 m i n u t e s , about 0.4 pglglhr7l. Much of the HT spontaneously r e l e a s e d f r o m n e u r a l s t r u c t u r e s can b e r e c o v e r e d unchanged f r o m the incubation m e d i a containing b r a i n slices72 o r isolated spinal cord73 o r in p e r f u s a t e s of the c e r e b r a l vent r i c l e s in which the HT is a s s u m e d t o come f r o m hypothalamus and caudate nucleus74. E l e c t r i c a l stimulation of a spinal c o r d p r e p a r a t i ~ n ~ ~ and t h e medulla oblongata75 is accompanied by a r e l e a s e of HT. Of special i n t e r e s t i s the observation that e l e c t r i c a l stimulation of the m i d b r a i n raphe, a n a r e a consisting e s s e n t i a l l y of HT-containing neurona1 p e r i k a r y a whose t e r m i n a l s p r o j e c t in v a r i o u s f o r e b r a i n regions, c a u s e s a fall i n HT and a n elevation in HIAA in the forebrain. Unilateral l e s i o n s of the m e d i a l f o r e b r a i n bundle prevent the stimulation-induced changes in indole concentrations only in t h e f o r e b r a i n i p s i l a t e r a l t o the l e s i o n , a n observation suggesting that the r e l e a s e of endogenous HT i s m e d i a t e d by a specific n e u r a l pathway76. Numerous drugs have been shown to deplete b r a i n of HT, a s well a s o t h e r biogenic amines2a 21, 77. R e s e r p i n e , the prototype of such drugs, m a y owe i t s sedative action t o the r a t e at which it depletes the b r a i n of HT78. A new agent, p-chloroamphetamine, depletes b r a i n of HT but not of catecholamines2, 3 , 79, 8 0 . Development and growth - B r a i n HT is lower in f e t a l and newb o r n rats than in the adult and i n c r e a s e s in e x t r a u t e r i n e life, a s do the catecholamines81. At b i r t h monoamine oxidase activity i s low but the decarboxylase is a s active a s in the m a t u r e rat82. The low l e v e l s of HT probably r e s u l t f r o m low activity of the enzyme that hydroxylates TP82, 8 3 . A l s o in rabbitsg4 and chicks83, b r a i n HT i n c r e a s e s during fetal and e a r l y postnatal life, but r e s u l t s on guinea pigs conflict85, 86. P i n e a l body and c i r c a d i a n rhythms - The pineal body i s r i c h i n biogenic a m i n e s , and the f o r m a t i o n and m e t a b o l i s m of HT, melatonin and o t h e r indoles w a s noted above871 8 8 , 41. HT i s found t h e r e in the pinealocytes and in the sympathetic n e r v e s 8 9 , a s c o n t r a s t e d with norepinephrine which i s found only in the latter9O and h i s t a m i n e which i s found in m a s t c e l l s within the pineal body91. At l e a s t s o m e of the HT found in the sympathetic n e r v e s m a y be f o r m e d by pinealocytes f r o m
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which the a m i n e is elaborated and then take up by the n e r v e endings89,3. Many i m p o r t a n t physiological actions a r e now being a s c r i b e d to melatonin899 42, 3 which is found only i n the pineal body. Among t h e s e is a n influence on pituitary m e c h a n i s m s controlling s e c r e t i o n of the melanocyte stimulating hormone and luteinizing hormone. Melatonin inhibits the e s t r o u s cycle in r a t s . The e s t r o u s cycle is m a r k e d l y influenced by light, which a l s o d e c r e a s e s the activity of hydroxyindole0 - m e t h y l t r a n s f e r a s e , the enzyme that f o r m s melatonin. Light inc r e a s e s the activity of H T P - decarboxylas e88. The diurnal rhythm in the activity of hydroxyindole- 0 - m e t h y l t r a n s f e r a s e depends on changes in light, w h e r e a s serotonin c i r c a d i a n rhythm i s endogenous a s it is not abolished by continuous d a r k n e s s o r by blinding, but c a n be s u p p r e s s e d by continuous light e x p o s u r e o r by s u p e r i o r c e r v i c a l ganglionectomy o r by section of preganglionic f i b e r s to the s u p e r i o r c e r v i c a l ganglion88. Both biological clocks a p p e a r t o be modulated by n e r v e i m p u l s e s g e n e r a t e d by p h o t o r e c e p t o r s (the r e t i n a in adult r a t s ) , c a r r i e d through the m i d b r a i n and b r a i n s t e m t o the spinal c o r d , to r e a c h the pineal through a pathway including preganglionic sympathetic f i b e r s t o the s u p e r i o r c e r v i c a l ganglionq2. One c e n t r a l pathway i s t h e m e d i a l f o r e b r a i n bundle, l e s i o n s of which s u p p r e s s pineal HT (and norepinephrine) rhythms a s w e l l as light induced v a r i a tions of hydroxyindole-0-methyl t r a n s f e r a s e (Moore and Heller42, 9 2 ) . The pineal bodies of the monkey, kangaroo and pigeon show c i r c a d i a n behavior s i m i l a r to that of the rat93. A c i r c a d i a n rhythm of pinealocyte m i t o t i c activity h a s a l s o been found in rat3. It should b e noted that c i r c a d i a n rhythms in HT l e v e l s have a l s o been found in the whole b r a i n of the m 0 u s e 9 ~and r a t 9 5 , in the c o r t e x of the rat96, and in the c e r e b r u m and b r a i n s t e m of the turtle97. Effects on CNS - A l a r g e n u m b e r of studies have been conducted on the effects of HT on spontaneous and evoked e l e c t r i c a l activity of the CNS2. HT, injected into the f e m o r a l vein of unanesthetized c a t s and rabbits, l o w e r s the level of functional activity of the c e r e b r a l c o r t e x and s u b c o r t i c a l s t r u c t u r e s , effects that a r e even m o r e evident a f t e r the injection of 5-methoxytryptamine98. When HT w a s injected into the c a r o t i d a r t e r y of the monkey, c o r t i c a l synaptic inhibitory actions w e r e seen, which w e r e a l s o s e e n with LSD-25 and which could b e blocked by c h l o r p r o m a z i n e ; this r e s p o n s e of the monkey is qualitatively identical in dogs and cats99. In the spinal c o r d of the cat, HT l e v e l s c a n be m a r k e d l y i n c r e a s e d by a n intravenous injection of T P o r H T P , with a c o n c u r r e n t l y l a r g e i n c r e a s e of monosynaptic spike height, accompanied by spontaneous motoneuronal d i s c h a r g e , while polysynaptic spiking is
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S i m i l a r effects w e r e s e e n a f t e r i n t r a c i s t e r n a l injection
Iontophoretic applicationlo2 of HT prompted inhibitory r e s p o n s e s in the neurons in both neo-103 and paleo-cortex104 of the c a t and on the hippocampal n e u r o n s of the c a t l 0 5 , 106 and of the rabbit107. Studies on the l a t e r a l geniculate nucleus of the c a t with t h i s technique have shown that HT d e p r e s s e s the orthodromic excitation of the single genicul a t e neurons t o volleys in the optic n e r v e f i b e r s , but do not affect antid r o m i c excitation elicited by e l e c t r i c a l o r c h e m i c a l stimulation of the optic radiationlog. Most n e u r o n s of the s a m e nucleus a r e d e p r e s s e d by HT and excited by acetylcholine and norepinephrine, w h e r e a s a few c e l l s , v e r y likely of the short-axon type, a r e excited by HT109. The olfactory bulb neurons of the rabbit respond to HT with a slowing of the spontaneous d i s c h a r g e r a t e l l o . In the hypothalamus of the c a t , those c e l l s that w e r e s e n s i t i v e t o HT (and norepinephrine) responded t o both a m i n e s with a d e c r e a s e in the r a t e of f i r i n g l l l . Iontophoretic application of HT on the l o w e r l u m b a r and l u m b o s a c r a l spinal i n t e r n e u r o n s have shown t h a t HT h a s a d e p r e s s a n t a c t i o n l l z , although s o m e neurons respond with e i t h e r facilitation o r d e p r e s s i o n of f i r i n g l l 3 . HT h a s been implicated in the control of body t e m p e r a t u r e . The suggestion that n o r m a l body t e m p e r a t u r e i s a reflection of a balance between the r e l e a s e of HT and catecholamines in the hypothalamus114 is complicated by s p e c i e s differences in r e s p o n s e s to both HT and catecholamines. Injections of HT into the c e r e b r a l v e n t r i c l e s 1 14 o r in the a n t e r i o r hypothalamus115 of the c a t and dogl16 produce a longlasting i n c r e a s e of body t e m p e r a a r e , accompanied by shivering. HT applied i n t r a v e n t r i c u l a r l y in the g o a t l l 7 , s h e e p l l 8 , rabbit119 and 0x12 p r o d u c e s a fall in body t e m p e r a t u r e . In c o n t r a s t with t h e s e findings in the rabbit a f t e r HT is injected into the v e n t r i c l e o r a n t e r i o r hypothalam u s , injection into the c i s t e r n a produces a h y p e r t h e r m i c r e s p o n s e l 2 1 . In the r a t , p-chlorophenylalanine depleted b r a i n of HT without affecting body t e m p e r a t u r e 3 . A provocative observation i s t h a t a substance r e l e a s e d f r o m the hypothalamus of a hypothermic monkey r a i s e d the t e m p e r a t u r e of another monkey when introduced into i t s t h i r d v e n t r i c l e ; the substance r e l e a s e d f r o m the hypothalamus, when a s s a y e d , w a s antagonized by bromo-LSD, a n antagonist of HT3. A r o l e of HT h a s b e e n postulated122 in H e s s ' trophotropic s y s t e m which i n t e g r a t e s the p a r a s y m p a t h e t i c s y s t e m with a c t i v i t i e s leading to sleep. P e r h a p s pertinent t o t h i s alleged r o l e i s the observed rhythm in HT l e v e l s in the b r a i n of m i c e and r a t s , the highest amounts being p r e s e n t when rodents sleep949 95. Raising b r a i n l e v e l s of HT in young chicks by the injection of HT o r HTP123,124 and in c a t s by drugs125
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produced electroencephalographic p a t t e r n s of sleep. The i n t r a c a r o t i d injection of HT had the s a m e effect probably by stimulating the bulbopontine hypnogenic a r e a s , via the a r e a p o s t r e m a l 2 6 . The injection of H T P into one portion of the bulbopontine hypnogenic a r e a of the r a b b i t produces a slow e l e c t r i c a l p a t t e r n of s l e e p , and into a n o t h e r portion of this a r e a a rapid p a t t e r n l 2 7 .
A m o s t striking c o r r e l a t i o n between HT telencephalic l e v e l s and s l e e p w a s p r e s e n t e d by Jouvet3. When a c a t w a s given p - c h l o r o phenylalanine, a m a r k e d depletion of b r a i n HT and total insomnia followed, which could b e r e v e r s e d by the a d m i n i s t r a t i o n of H T P (which b y - p a s s e s t h e inhibited s t e p in HT b i o s y n t h e s i s ) . Destruction of the m i d b r a i n raphe, w h e r e the m a j o r i t y of s e r o t o n e r g i c p e r i k a r y a a r e 7 6 , produced a fall in HT in the telencephalon without a l t e r i n g l e v e l s of catecholamines. Total d e s t r u c t i o n of the m i d b r a i n raphe produced a n a r o u s a l p a t t e r n with a s e v e r e reduction in daily sleeping t i m e f r o m the n o r m a l of 60 p e r cent t o 3.5 p e r cent. The extent of d e s t r u c t i o n of t h e raphe nuclei is w e l l - c o r r e l a t e d with telencephalic l e v e l s of HT, the electroencephalographic p a t t e r n , and amount of sleep. I n m a n , o r a l a d m i n i s t r a t i o n of T P r e d u c e s the duration of the f i r s t phase of slow-wave (non-dreaming) s l e e p and provokes a n a b n o r m a l l y e a r l y onset of the second p h a s e of paradoxical ( d r e a m i n g , rapideye-movement) sleep. In patients with n a r c o l e p s y , w h e r e paradoxical s l e e p is t h e f i r s t p h a s e , this phase i s prolonged. In both c a s e s T P effects a r e blocked by m e t h y d e r g i d e l 2 8 . M e t h y s e r g i d e , a n antagonist of HT, blocks the e a r l y onset of d r e a m i n g sleep128; it a l s o c a u s e s insomnial26. The possibility that HT m a y be catabolized t o hallucinogenic s u b s t a n c e s w a s mentioned above. This possibility, together with the o b s e r v e d hallucinogenic activity of m a n y indoles, h a s prompted the idea that m e t a b o l i s m of HT m a y play a r o l e in schizophrenia, a subject t h a t has been reviewed671 129. One of the provocative observations, f i r s t m a d e by Kety and h i s a s s o c i a t e s , i s that feeding a combination of tryptophan and methionine c a n induce s y m p t o m s of schizophrenia. Studies of the effect of HT on affective s t a t e s and behavior12 2 , 67, 1 2 9 - 132 cannot b e d i s c u s s e d f a i r l y i n a s h o r t review. A r o l e of HT m e t a b o l i s m in the m e n t a l r e t a r d a t i o n of phenylketonurial33 r e m a i n s unproved, although it has been noted that phenylalanine inhibits t r a n s p o r t and hydroxylation of T P 3 .
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28 1 -
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Topics i n Biology
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211,
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Chapter 27. Regulation of Cell Metabolism: Role of Cyclic Cnarles G. Smith, The Upjohn Company, Kalamazoo, Michigan Cyclic 3',5'-adenylic acid (cyclic AMP), the structure of which is shown in Figure 1, was isolated from animal tissue by Sutherland and Pall''', while investigating the mechanism by which epinephrine exerts its glycogenolytic effect in liver and muscle. These and subsequent investigations in various laboratories suggested a role for cyclic AMP as a modifier or mediator of pho~phorylase~'", UDFG-~-transglucosylase7 phosphofructokinases, lipasel' tryptophan pyrrolase12, steroid~genesisl~-~~ '*a J15b ,ketogenesis'" , amino acid uptake into liver proteins17, acetate incorporation into liver fatty acids and cholesterol16, lactate conversion to glucoseLs, release of amylase'@, water and ion permeability in the toad bladder20'21, sugar transport in thyroid tissue22 and acid secretion in the gastric mucosa23. In addition, this nucleotide has been implicated in the actions of g l ~ c a g o n ~ACTH3, ~, vasopressin=, luteinizing hormones , thyroid stimulating hormone=, serotonina, acetyl cholinem, prostaglandin1'", histamine%, melanocyte-stimulating and i n s ~ l i n X ~ ' ~ ~Several C. recent papers have appeared in which the role of cyclic AMP as a hormone mediator or "second messenger" has been described in some detai131-3s and a suggestion that adenyl cyclase may It is the actually be the adrenergic receptor site has also been made3'". purpose of this communication to center discussion on the possible value of cyclic AMP, and test systems for measuring its effects, to the medicinal chemist. Synthesis and Degradation of Cyclic AMP Adenyl cyclase - The synthesis of cyclic AMP from ATP is catalyzed by the enzyme adenyl cyclase, which itself is responsive to hormone stimulation in various tissues3'. Catecholamines have been shown to stimulate the formation of cyclic AMP in a variety of tissues3' (Table 133), and adenyl cyclase has been shown to be wide-spread in various tissues39. Since procedures for the isolation and assay of this enzyme and measurement of the products of its reaction are available3' direct effects of analogues of ATP and/or cyclic AMP (or hormones) on the enzyme can be determined in an in vitro system. The degradation of cyclic AMP is catalyzed by a specific phosphodiesterase which converts it to adenylic (Figure 1). Again, the effect of nucleotide analogues or other potential inhibitors on the degradation of cyclic AMP can be studied in vitro in this enzyme system, and the possible significance of such agents will be discussed below. Cyclic 3',5'-AMF'as a Hormone Mediator
-
The phosphorylase system While investigating the site of the glycogenolytic action of epinephrine, Sutherland and Cori4' demonstrated the stimulation of phosphorylase activity by this catecholamine and subsequent studies' '32' 43
'la,
Chap. 27
Cell Metabolism
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implicated c y c l i c AMP i n t h i s process. Krebs, e t al.32, have r e c e n t l y r e viewed t h e s u b j e c t o f a c t i v a t i o n of s k e l e t a l muscle phosphorylase under t h e influence of epinephrine, mediated by c y c l i c AMP. Figure 2 , adapted from t h e i r paper, summarizes t h e s t e p s which have been shown t o be involved i n t h i s process. The d i r e c t a c t i v a t i o n of phosphorylase b k i n a s e i n muscle e x t r a c t can be demonstrated upon t h e a d d i t i o n of c y c l i c AMP i n v i t r o 4 3 , 4 4 . The a c t i v a t i o n of phosphorylase by epinephrine has a l s o been demonstrated i n t h e perfused h e a r t and i n t a c t h e a r t i n s i t u 3 5 . Thus, t h r e e enzymatic systems a r e a v a i l a b l e which can be s t u d i e d i n i s o l a t e d c e l l p r e p a r a t i o n s f o r e f f e c t s of analogues or chemically u n r e l a t e d compounds on e i t h e r t h e s y n t h e s i s or degradation of c y c l i c AMP or enzymatic a c t i v a t i o n by t h i s nucleotide. The p h o ~ p h o d i e s t e r a s e ~which l cleaves c y c l i c AMP i s i n h i b i t e d by methyl xanthines and it i s e n t i r e l y p o s s i b l e t h a t some or a l l of t h e b i o l o g i c a l a c t i v i t y observed f o r t h e s e i n h i b i t o r s of c y c l i c AMP degradation may be due t o t h i s a c t i o n . For example, t h e o p h y l l i n e has been shown t o i n c r e a s e phosphorylase a a c t i v i t y i n t h e i s o l a t e d h e a r t and p o t e n t i a t e t h e e f f e c t s of epinephrine in t h i s assaya5. E f f e c t s on l i p o l y s i s - I n a r e c e n t a r t i c l e , Butcher37 reviews t h e h i s t o r y o f t h e i r experiments on t h e r o l e of t h e c y c l i c AMF i n t h e l i p o l y t i c process. T h e i r i n v e s t i g a t i o n s showed an i n c r e a s e i n t h e concentration of c y c l i c AMP upon t h e a d d i t i o n of epinephrine t o f a t pads i n v i t r o , followed by a s t i m u l a t i o n of t h e r e l e a s e of f r e e f a t t y a c i d s . Caffeine, a known i n h i b i t o r o f t h e phosphodiesterase which degrades c y c l i c AMP, a c t e d s y n e r g i s t i c a l l y with epinephrine on t h e accumulation of c y c l i c AMP and t h e subsequent r e l e a s e of f r e e f a t t y acid^^^,^^. It should be noted t h a t t h e l i p o l y t i c e f f e c t of epinep h r i n e w a s decreased by d i c h l o r o i s o p r o t e r e n o l , a known i n h i b i t o r of t h e s t i m u l a t i o n of adenyl cyclase by c a t e ~ h o l a r n i n e ~ " ~ ~I n . s p i t e of t h i s e v i dence f o r t h e r o l e of c y c l i c AMP as a mediator i n t h e l i p o l y t i c process, t h e d i r e c t a d d i t i o n of t h i s n u c l e o t i d e t o f a t pads i n v i t r o d i d not s t i m u l a t e f a t t y a c i d r e l e a s e 4 5 , although p e n e t r a t i o n i n t o t i s s u e by t h e n u c l e o t i d e w a s low. When t h e Ne-2'-O,dibutyryl e s t e r of c y c l i c 3',5'-AMP4e w a s added t o f a t pads or f a t pads were perfused with t h i s compound, s t i m u l a t i o n of t i s s u e f r e e f a t t y a c i d s y n t h e s i s and f r e e f a t t y a c i d r e l e a s e w a s noted. The subs t i t u t e d compound w a s a t l e a s t t e n times as a c t i v e i n t h i s system as w a s c y c l i c AMF per se. The d i b u t y r y l d e r i v a t i v e may p e n e t r a t e t i s s u e more e f f e c t i v e l y t h a n does t h e u n s u b s t i t u t e d n u c l e o t i d e , but a l s o it i s degraded by t h e c y c l i c phosphodiesterase more slowly t h a n i s t h e p a r e n t compound 3 7 . T h i s i s indeed a n e x c i t i n g example t o t h e medicinal chemist of a r e l a t i v e l y simple chemical s u b s t i t u t i o n which r e s u l t s i n a marked change i n t h e a b i l i t y of a compound t o p e n e t r a t e t i s s u e and withstand t h e degradation t h a t i t s p r o g e n i t o r undergoes. A t t h e same time, t h e substance obviously can be conv e r t e d , a l b e i t slowly, t o t h e a c t i v e c y c l i c AMP and a c t as a " s l o w f e e d " of the latter. E f f e c t s on s t e r o i d o g e n e s i s - E a r l y investigation^^^'^ showed t h a t incubation of beef a d r e n a l s l i c e s with ACTH r e s u l t e d i n an i n c r e a s e i n t h e c y c l i c AMP l e v e l i n t h i s t i s s u e and t h a t added c y c l i c AMP s t i m u l a t e d c o r t i c o i d sylrthesis i n r a t a d r e n a l s l i c e s . More r e c e n t l y , Karaboyas and K o r i t z & s t u d i e d t h e
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mechanism of s t i m u l a t i o n of c o r t i c o i d s y n t h e s i s i n r a t and beef a d r e n a l c o r t e x s l i c e s and concluded t h a t c y c l i c AMP and ACTH a f f e c t t h e same s i t e i n t h e b i o s y n t h e t i c pathway between c h o l e s t e r o l and pregnenolone. They f u r t h e r suggested t h a t c y c l i c AMP i s a n o b l i g a t o r y intermediate i n t h e a c t i o n ~~ that of ACTH. I n another r e c e n t paper, Roberts and c o - w ~ r k e r sconcluded 5 l - M (as w e l l as c y c l i c AMP) s t i m u l a t e s s t e r o i d hydroxylation i n adrenal mitochondria. The mechanism whereby c y c l i c AMP enhances s t e r o i d hydroxyla t i o n i n t h i s system i s unknown. I n t h e i r hands, hydroxylation of s t e r o i d could not be obtained even a t high l e v e l s of c y c l i c AMP i f t h e a d r e n a l mitoc h o n d r i a l system or homogenate d i d not c o n t a i n reduced NADP, and t h e y suggest as p o s s i b l e explanations f o r t h e a c t i o n of t h i s n u c l e o t i d e 1) increased s t i m u l a t i o n of t h e t r a n s p o r t of s t e r o i d ( o r co-factor ) a c r o s s mitochondria1 membranes o r 2 ) d i r e c t a c t i v a t i o n of t h e s t e r o i d hydroxylase system. Creange and Roberts on t h e o t h e r hand, a l s o studying t h e mechanism of ll-fbhydroxyla t i o n , concluded t h a t c y c l i c AMP s e l e c t i v e l y stimulated t h i s process i n t h e a d r e n a l c o r t e x by a mechanism which i s independent of glycogen phosphoryla t i o n , reduced NADP g e n e r a t i o n and endogenous c o r t i c o i d precursorss1. I n 1964, Marsh and Savards2 r e p o r t e d t h a t l u t e i n i z i n g hormone increased t h e l e v e l of phosphorylase a c t i v i t y i n bovine corpora l u t e a , t h a t t h i s response w a s s p e c i f i c f o r t h e hormone and t h a t a high degree of c o r r e l a t i o n e x i s t e d between t h e e x t e n t o f phosphorylase s t i m u l a t i o n and t h e degree o f progesterone s t i m u l a t i o n by l u t e i n i z i n g hormone. I n t h e i r s t u d i e s , exogenous c y c l i c AMP d i d not s t i m u l a t e l u t e a l phosphorylase a c t i v i t y . More r e c e n t l y , Marsh and c o l l a b o r a t o r s 5 showed t h a t l u t e i n i z i n g hormone s t i m u l a t e d t h e production of c y c l i c AMP i n bovine corpora l u t e a incubated i n v i t r o and t h a t t h i s i n c r e a s e preceded progesterone s y n t h e s i s . Again t h e e f f e c t w a s r e p o r t e d t o be s p e c i f i c f o r l u t e i n i z i n g hormone. These i n v e s t i g a t o r s a l s o demonstrated a n i n c r e a s e i n t h e c o n c e n t r a t i o n o f c y c l i c AMP i n a human corpus luteum s t i m u l a t e d Ln v i t r o by human chorionic gonadotrophin. Other e f f e c t s of c y c l i c AMP i n v i t r o - I n a r e c e n t paper, Appleman and coworkers5 concluded t h a t many s i m i l a r i t i e s e x i s t between t h e ATP-cyclic AMP a c t i v a t i o n of phosphorylase b k i n a s e and t h e conversion of glycogen synthetase from t h e independent t o t h e glucose 6-phosphate-dependent form. C e r t a i n i n t e r e s t i n g e f f e c t s on i o n and water permeability a r e a l s o thought t o be mediated by c y c l i c AMP. Handler, e t a1.=, r e p o r t e d t h a t e i t h e r a r g i n i n e vasopressin or t h e o p h y l l i n e s i g n i f i c a n t l y i n c r e a s e d t h e concentration of c y c l i c AMP i n t h e i s o l a t e d toad bladder and t h a t t h e two t o g e t h e r were synergistic. Cyclic AMP w a s a l s o r e p o r t e d t o have t h e same e f f e c t as vasop r e s s i n on t h e permeability of t h e bladder t o water and sodium i o n and, accordingly, w a s concluded t o a c t as a n i n t r a c e l l u l a r mediator of t h e vasop r e s s i n e f f e c t . It i s i n t e r e s t i n g t h a t t h i s n u c l e o t i d e has a l s o been r e p o r t e d t o i n c r e a s e d i u r e s i s i n vivo, as described below. Although t h y r o i d s t i m u l a t i n g hormone (TSH) has been r e p o r t e d t o i n c r e a s e l e v e l s of c y c l i c AMP i n t h y r o i d homogenates and s l i c e s = ' s 6 , t h e n u c l e o t i d e d i d not i n c r e a s e Ci402 production from glucose nor t h e i n c o r p o r a t i o n of $2phosphate i n t o phospholipids i n v i t r o , as w a s observed with TSH p e r seS6 ' 5 7 . More r e c e n t l y , Pastans8 r e p o r t e d a s i g n i f i c a n t s t i m u l a t i o n of both of t h e s e
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p r o c e s s e s by t h e d i b u t y r y l d e r i v a t i v e o f c y c l i c AMP a t c o n c e n t r a t i o n s as low as 50 pg/mL b u t not by c y c l i c AMP a t f i v e t i m e s t h i s c o n c e n t r a t i o n . TSH, as expected, s t i m u l a t e d b o t h p r o c e s s e s a t low c o n c e n t r a t i o n . Again, as mentioned above under l i p o l y t i c s t u d i e s , t h e enhanced a c t i v i t y of t h e d i b u t y r y l s u b s t i t u t e d n u c l e o t i d e should be noted. Metabolic E f f e c t s of Cyclic AMP i n Whole Animals A s mentioned e a r l i e r , c y c l i c AMP has been p o s t u l a t e d as t h e c e l l u l a r i n t e r mediate i n t h e a n t i - d i u r e t i c a c t i o n of v a s o p r e ~ s i '21y25 n ~ ~ j 5 9 y60 i n i s o l a t e d dog kidney homogenates and i s o l a t e d t o a d b l a d d e r . Based orAt h e s e o b s e r v a tions, Levine s t u d i e d t h e e f f e c t of c y c l i c AMP on d i u r e s i s i n v i v o and r e p o r t e d a prompt a n t i - d i u r e t i c e f f e c t a f t e r i n j e c t i o n of t h e n u c l e o t i d e Levine and VogelG2 a l s o determined t h e e f f e c t of t h e c y c l i c i n man61. n u c l e o t i d e on h e a r t r a t e , c a r d i a c o u t p u t , mean blood p r e s s u r e , t o t a l p e r i p h e r a l r e s i s t a n c e , s t r o k e volume,pulse p r e s s u r e , blood g l u c o s e and plasma f r e e f a t t y a c i d s i n i n t a c t dogs and r e p o r t e d t h a t a d m i n i s t r a t i o n of a s i n g l e dose produced e f f e c t s i n t h e whole animal resembling t h o s e of c a t e cholamines. They r e p o r t e d no s i g n i f i c a n t changes i n c a r d i a c o r m e t a b o l i t e f u n c t i o n s f o l l o w i n g a d m i n i s t r a t i o n of t h e 2 l - , 3 * - o r 5'-AMP, ATP or s a l i n e , a l t h o u g h p r i o r a d m i n i s t r a t i o n of d i c h l o r o i s o p r o t e r e n o l p r e v e n t e d t h e c a r d i o v a s c u l a r (but n o t t h e m e t a b o l i c e f f e c t s ) of c y c l i c AMP. The l a t t e r nucleot i d e has a l s o been i m p l i c a t e d i n t h e mechanism o f myocardial ~ o n t r a c t i l i t ~ ~ - "
General C o n s i d e r a t i o n s Examination o f a v a i l a b l e d a t a c l e a r l y i n d i c a t e s a r o l e f o r c y c l i c AMP as a mediator of t h e catecholamine s t i m u l a t i o n of g l y c o g e n o l y s i s , b y t h e mechanism d e p i c t e d i n F i g u r e 2. Unlike t h e a t t e m p t s t o demonstrate t h e s i t e of a c t i o n of most p r o t e i n and s t e r o i d hormones66, t h e expected i n c r e a s e s i n each of t h e enzyme a c t i v i t i e s presumed t o b e mediated by c y c l i c AMP can be demons t r a t e d with d i r e c t i n v i t r o techniques after treatment of t h e appropriate t i s s u e w i t h s p e c i f i c hormones. A s a n example, adenyl c y c l a s e a c t i v i t y and c y c l i c AMP i n c r e a s e upon t r e a t m e n t w i t h e p i n e p h r i n e and t h i s i n t u r n can b e shown, a t t h e enzymatic l e v e l , t o a c t i v a t e phosphorylase k i n a s e . The l a t t e r enzyme c o n v e r t s phosphorylase b t o phosphorylase a which i s t h e a c t i v e form o f t h e enzyme c a t a l y z i n g t h e s y n t h e s i s of glucose-1-phosphate from glucagon. The o p p o r t u n i t i e s f o r t h e m e d i c i n a l chemist t o s t u d y analogues and d e r i v a t i v e s o f t h e simple n u c l e o t i d e s o r o f compounds r e l a t e d t o t h e catecholamines a r e unusual i n t h a t s e v e r a l enzymatic s t e p s i n a known sequence of r e a c t i o n s can b e measured q u a n t i t a t i v e l y i n v i t r o and e f f e c t s of s t i m u l a t o r s o r i n h i b i t o r s can b e d i r e c t l y a s s e s s e d . The d a t a i m p l i c a t i n g c y c l i c AMP i n t h e l i p o l y t i c p r o c e s s are a l s o q u i t e convincing, and t h e concept of c y c l i c n u c l e o t i d e mediation of ACTH i n s t e r o i d o g e n e s i s and v a s o p r e s s i n a c t i o n on water and i o n t r a n s p o r t a c r o s s nembranes i s a l s o sound. I n v i v o , c y c l i c AMP e x e r t s many of t h e e f f e c t s observed w i t h c a t e cholamines and, i n v a r i o u s systems, t h e methylxanthines (e.g., t h e o p h y l l i n e ) , which a r e known t o i n h i b i t t h e p h o s p h o d i e s t e r a s e t h a t c l e a v e s t h e n u c l e o t i d e , a l s o p o t e n t i a t e i t s a c t i o n . I n a d d i t i o n , t h e c y c l i c n u c l e o t i d e has been i m p l i c a t e d i n v a r i o u s s t e p s i n t h e gluconeogenic pathway, t h e mechanism o f a c t i o n of l u t e i n i z i n g hormone, glycogen s y n t h e t a s e and t h e metabolism of
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thyroid t i ssue . Although it is not uncommon t o a s s o c i a t e s i n g l e co-enzymes with d i f f e r e n t enzymes c a t a l y z i n g s i m i l a r t y p e s of r e a c t i o n s (e.g., ATP w i t h k i n a s e s , NADP w i t h reductases, and t h e l i k e ) , it i s not common t o t h i n k of a s i n g l e small molecule as a mediator of a wide v a r i e t y of hormonal o r metabolic r e a c t i o n s . Since adenyl c y c l a s e i s membrane bound, it i s p o s s i b l e t h a t s t e r e o - s p e c i f i c attachment s i t e s on t h e c e l l s u r f a c e t o which t h e p a r t i c u l a r p r o t e i n o r s t e r o i d hormone binds a c t i v a t e t h e s y n t h e s i s of t h e c y c l i c nucleotide i n a p a r t i c u l a r c e l l u l a r compartment, i n which it t h e n a f f e c t s t h e a c t i v i t y of another enzyme (e.g., phosphorylase kinase, l i p a s e , o r t h e l i k e ) , thereby ~~ completing t h e response i n i t i a t e d a t t h e c e l l surface. S ~ t h e r l a n dand T a l w a r 6 7 e l a b o r a t e d a d d i t i o n a l p o s s i b i l i t i e s whereby adenyl cyclase can mediate d i f f e r e n t hormone e f f e c t s : 1) d i f f e r e n t a f f i n i t i e s of a s i n g l e r e c e p t o r s i t e f o r d i f f e r e n t hormones, 2 ) m u l t i p l e s i t e s on a s i n g l e r e c e p t o r molecule, 3 ) unique responses i n d i f f e r e n t c e l l s t o t h e a c t i v a t i o n of adenyl cyclase , 4 ) d i f f e r e n t c o f a c t o r requirements of t h e v a r i o u s cyclase:;, and 5 ) c e l l u l a r compartmentalization e f f e c t s . Regardless of t h e exact mechanism of a c t i o n , epinephrine can b e shown both i n v i t r o and i n vivo t o i n c r e a s e t h e a c t i v i t y of adenyl cyclase and t h i s e f f e c t can be s t i m u l a t e d or i n h i b i t e d by substances which antagonize t h e s y n t h e s i s o r degradation of c y c l i c AMP. I n t h e case of l i p o l y s i s , t h e r e appears t o be a d i r e c t c o r r e l a t i o n between t h e l e v e l s of c y c l i c AMP achieved and t h e amount of f r e e f a t t y a c i d r e l e a s e d , which a l s o s t r o n g l y i m p l i c a t e s t h e c y c l i c n u c l e o t i d e as a hormone mediator Coupled with t h i s f a c t , it m u s t be r e c a l l e d t h a t i n t h i s system as well. c y c l i c AMP mimics t h e e f f e c t of epinephrine i n l i v e r s l i c e s and causes hyperzlycemia i n v a r i o u s i n t a c t animals including humans"'. acid r e s i s t s the cyclic The f i n d i n g t h a t N6-21-O-dib~tyryl-3',5'-adenylic phosphodiesterase but p e n e t r a t e s c e l l s more r e a d i l y t h a n c y c l i c AMP i t s e l f i s of g r e a t t h e o r e t i c a l and p r a c t i c a l i n t e r e s t t o t h e medicinal chemist. This r e p r e s e n t s a s i t u a t i o n toward which many i n v e s t i g a t o r s s t r i v e i n prep a r i n g s u b s t i t u t e d d e r i v a t i v e s and analogues of pharmacologically a c t i v e compounds. Very seldom, however, a r e such c l e a r - c u t advantages f o r a r e l a It i s s u r p r i s i n g t o t h i s reviewer t h a t t i v e l y simple d e r i v a t i v e r e a l i z e d . considerably more work has not been done t o d a t e , both i n v i t r o and i n whole animals, with t h e d i b u t y r y l compound. It i s not only imperative t h a t s u f f i c i e n t q u a n t i t i e s of t h i s substance be prepared f o r broad e v a l u a t i o n i n experimental animals t o determine t h e o v e r a l l pharmacological p r o p e r t i e s o f t h i s unique substance, b u t a d d i t i o n a l r e l a t e d d e r i v a t i v e s w i t h v a r i e d s i d e chains a l s o seem worth i n v e s t i g a t i n g . It i s p o s s i b l e t h a t t h e p r e p a r a t i o n of s i m i l a r s u b s t i t u t e d nucleosides o r n u c l e o t i d e s o f bases o t h e r t h a n adenine might r e s u l t i n increased p e r m e a b i l i t y i n s p e c i f i c t i s s u e s and decreased r a t e of h y d r o l y s i s t o nucleosides. Analqgues o f c y c l i c AMP p e r s e may a l s o be worthy of i n v e s t i g a t i o n i n view o f t h e f a c t t h a t a s p e c i f i c enzyme s y n t h e s i z e s t h i s compound. The enzyme may be l o c a l i z e d s e l e c t i v e l y i n v a r i o u s t i s s u e s and a s p e c i f i c c y c l i c phosphod i e s t e r a s e i n a c t i v a t e s t h e substance by forming 5l-AVP. Thus, enzyme systems i n which t h e medicinal chemist can e v a l u a t e compounds i n a di-ect manner f o r t h e i r a b i l i t y t o a c t i n p l a c e o f c y c l i c AMP o r i n h i b i t i t s a c t i o n o r degradation
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a r e a v a i l a b l e . One c l o s e r e l a t i v e of c y c l i c AMP, c y c l i c t u b e r c i d i n phosphate6', has been t e s t e d by Butcher and Sutherland (unpublished o b s e r v a t i o n s ) and shown t o r e p l a c e c y c l i c AMP as an a c t i v a t o r of phosphorylase. C e r t a i n l y a wide v a r i e t y of s u b s t i t u t e d p u r i n e analogues and 2 ' - s u b s t i t u t e d c y c l i c AMP d e r i v a t i v e s or analogues should be prepared and i n v e s t i g a t e d i n t h e abovementioned enzyme systems. The u b i q u i t y of c y c l i c AMP (animal t i s s u e s , u r i n e and E. -~ 0 l i 6 9 )and t h e occurrence of t h e c y c l i c monophosphates of guanosine and p o s s i b l y u r i d i n e i n nature70 '7 f u r t h e r s t r e n g t h e n t h e p o t e n t i a l importance of t h e s e compounds i n o v e r a l l r e g u l a t i o n of metabolism, and extend t h e f i e l d of s y n t h e s i s of p o s s i b l e analogues or d e r i v a t i v e s t o t h i s e n t i r e family o f n u c l e o t i d e s . It should be emphasized t h a t s e l e c t i v e or s p e c i f i c i n h i b i t i o n of t h e a c t i o n of t h e progenitor substance i s not t h e only b a s i s f o r i n t e r e s t i n d e r i v a t i v e s and analogues of compounds r e l a t e d t o c y c l i c AMP. Increased h a l f - l i f e of t h e molecule i n t h e animal body, allowing it t o b e c a r r i e d t o s p e c i f i c organs i n higher concentration t h a n t h e p a r e n t compound, can be a decided advantage. Likewise, s e l e c t i v e organ concentration of d e r i v a t i v e s o r analoguesorchanges i n r a t e of c e l l u l a r k i n e t i c s can a l t e r t h e o v e r a l l metabolism and d i s t r i b u t i o n p i c t u r e as w e l l as t h e b i o l o g i c a l e f f e c t s observed Marked changes i n p o l a r i t y of t h e compound w i t h s u b s t i t u t e d nucleotides68 '72. may s i g n i f i c a n t l y i n f l u e n c e passage a c r o s s t h e blood-brain b a r r i e r r e s u l t i n g i n pharmacologically a c t i v e doses of a compound i n t h e nervous system where t h e p a r e n t accumulates i n only v e r y low concentrations. Obviously, it cannot be p r e d i c t e d whether such changes w i l l be f a v o r a b l e of unfavora5le t o t h e animal i n which t h e y are induced. When t h e c y c l i c AMP and c y c l i c n u c l e o t i d e p i c t u r e i s considered i n t o t o , it emerges as a f a s c i n a t i n g a r e a of biochemistry and biology i n which t h e medicinal chemist ought t o p l a y a s i g n i f i c a n t r o l e i n t a i l o r i n g molecules f o r c e r t a i n enzymatic a c t i v i t i e s which can be d i r e c t l y measured i n v i t r o and evaluated i n v a r i o u s s p e c i e s of whole animals, including man, where i n d i c a t e d .
-
Sect. V
292 -
Tabachnick, Ed.
Topics i n Biology
Figure 1
0
I
0
II H OI - P 1- O - P - O - ~ ~ ~ II
0
0
I
H
-7OH
0- -OH
OH
OH
Adenyl Cyclase
9
Activated by hormones
I
ATP
Cyclic-AMP
Phosphod i esterase
T
F2
I n h i b i t e d by methyl x a n t h i n e s 0
II
OH
OH
5'
B i o s y n t h e s i s and Degradation of Cyclic AMP
Smith
Cell Metabolism
Chap. 27
Figure 2 The Mechanism of Action of Epinephrine oh Glycogenolysis in Muscle Epinephrine
J
Adenyl cyclase
Cyclic 3' ,5'-AMP
ATP
n Enzyme ( ? )
Nonactivated
Activated
phosphorylase kinase
phosphorylase kinase
2
+ ATP Phosphorylase
Glycogen
+ Pi
Phosphorylase 5
Glucose-1-P
294 -
Sect. V
-
Topics i n Biology
Tabachnick, Ed.
References
(2)
E. W. Sutherland and T. W. R a l l , J. Am. Chem. Soc. 79, 3608 (1957). E. W. Sutherland and T . W . R a l l , J. B i o l . Chem. %?lo77 (1958).
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(13) (14) 533 (1965). (15) J. E. Creange and S. Roberts, Biochem. Biophys. Res. Comm. 3, 73 (1965). ( l 5 a ) J. M. Marsh and K. Savard, S t e r o i d s 4, 133 (1966). ( l 5 b ) P. F. H a i l and S. B. K o r i t z , Biochemistrx,$, 1037 (1965). (16) J . B e r t h e t , Proc. Fourth I n t l . Cong. Biochem. 15, lo7 (1960). (17) J . Pryor and J. Be'rthet, Biochim. Biophys. Acta $ 3 , 556 (19601. (18) J. H. Exton and C. R. Park, Fed. Proc. 24, 537 (1965). (19) A. Bdolah and M. Schramm, Biochem. Biophys. Res. Corm. ;,8, 452 (1965). (20) J. O r l o f f and J . S. Handler, J. C l i n . I n v e s t . ,$A, 702 (1962). (21) B. S. S t r a u c h and R. G. Langdon, Biochem. Biophys. Res. Comm. :6, 27 (1964). (22)
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,A?,
329 (1963). (23) J. B. H a r r i s and D. Alonso, Fed. Proc. 2 2 , 623 (1963). (24) M. H . Makman and E. W. S u t h e r l a n d , Endocrinology 75, 127 (1964). J. S . Handler, R. W . Butcher, E. W. S u t h e r l a n d a n r J . O r l o f f , J. Biol. Chem. (25) 240, 4524 (1965). (26) J. M. Marsh, R. W. Butcher, K. Savard and E. W. S u t h e r l a n d , Fed. Proc. 24, 320, ".,.,., (1965). ( 2 7 ) P. L. M. K l a i n e r , Y.-M. C h i , S. L. F r e i d b e r g , T . W. R a l l , E. W. S u t h e r l a n d , J. Biol. Chem. 727, 1239 (1962). ( 2 8 ) T. E. Mansour, E. W. S u t h e r l a n d , T. W. R a l l and E. Bueding, J. B i o l . Chem. 235, 466 ( 1 9 6 ~ ) . Chi, T . W. R a l l and E. W . S u t h e r l a n d , J . Biol. Chem. 2 3 7 , 1233 (1962). ( 2 9 ) F. Murad, Y.-M. (30) S. Kakiuchi and T. W . R a l l , Fed. Proc. 24, 150 (1965). (30a) M. W. Bitensky and S. R. B u r s t e m , Nature 208, 1282 (1965). (30b) R. W.
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+TI
( 3 0 ~ G. ) S c h u l t z , G . S e n f t and K. Munske, Naturwissenschaften 53, 529 (1966). (31) E. W . Sutherland and G. A . Robison, Pharmacol. Rev. 18, 145 (1966).
(32) E . G. Krebs, R. J . De Lange, R. G. Kemp and W. D. R i l e y , Pharmacol. Rev. 18, 163 (1966). (33) J . H. Exton and C. R . Park, Pharmacol. Rev. 18, 181 (1966). ( 3 4 ) E. Helmreich and C. Cori, Pharmacol. Rev. 18: 189 (1966). (35) N. Haugaard and M. E. Hess, Pharmacol. Rev. 18, 197 (1966).
Chap. 27
*
295 -
Smith
Cell Metabolism
(36) J. R. W i l l i a m s o n , Pharmacol. Rev. $$, 205 (1966). 8 , 237 (1966). (37) R. W. B u t c h e r , Pharmacol. Rev. ; (38) Fr. H u i j i n g and J . L a m e r , P r o c . N a t l . Acad. S c i . 2,647 (1966). (38a) G. A. Robison, R . W . B u t c h e r and E . W . S u t h e r l a n d , Annals N . Y . Acad. S c i . , i n p r e s s (1967). (39) E. W . S u t h e r l a n d , T. W . R a l l and T. Menon, J . B i o l . Chem. k32, 1220 (1962). (40) J . G . Hardman, J . W. Davis and E . W . S u t h e r l a n d , J . B i o l . Chem. 2A1, 4812 (1966). (41) R. W. B u t c h e r and E. W . S u t h e r l a n d , J . B i o l . Chem. 227, 1244 (1962). (42) E. W. S u t h e r l a n d and C . F. C o r i , J . B i o l . Chem. $88, 531 (1951). (43) T. W. R a l l , E . W . S u t h e r l a n d and J . B e r t h e t , J . B i o l . Chem. 2&4, 463 (1957). (44) E. G . Krebs, D. J . Graves and E. H. F i s c h e r , J. B i o l . Chem. 2 4 , 2867 (1959). (45) M. Vaughn, J. B i o l . Chem. g?, 3049 (1960). (46) T. P o s t e r n a k , E. W . S u t h e r l a n d and W . F. Henion, g o c h i m . Biophys. Acta 9 , 558 (1962). 1220 (1958). (47) R. C. Haynes, J r . , J . B i o l . Chem. (48) R . C. Haynes, J r . , S. B. K o r i t z and F. G. P e r o n , J. B i o l . Chem. 2A4, 1421 (1959). (49) G. C. Karaboyas and S. B. K o r i t z , B i o c h e m i s t r y k, 462 (1965). (50) S. R o b e r t s , J . E. Creange and P . L. Young, N a t u r e 188 (1965). (51) J . E. Creange and S . R o b e r t s , Biochem. Biophys. Res. Comm. 9, 73 (1965). (52) J. M. Marsh and K. S a v a r d , J . B i o l . Chem. 1 (1964). (53) J. M. Marsh, R . W . B u t c h e r , K. Savard and E. W . S u t h e r l a n d , J . B i o l . Chem. Z&, 5436 (1966). (54) M. Appleman, L. Birnbaumer and H. N . T o r r e s , Arch. Biochem. Biophys. 2 6 , 39 (1966). (55) A. G. Gilman and T. W. R a l l , Fed. Proc. 3, 617 (1966). (56) J . B. F i e l d , I . H. P a s t a n , P. Johnson and B. H e r r i n g , J . B i o l . Chem. 235. 1863 (1960). (57) J . B. F i e l d , I . H . P a s t a n , B. H e r r i n g and P . Johnson, Biochim. Biophys. Acta ZQ., 513 (1961). (58) I. H. P a s t a n., &>, 14 (1966). (59) J . O r l o f f and J . S. H a n d l e r , Amer. J . Med. 26, 686 (1964). (60) I . S. Edelman, M. J . P e t e r s e n and P. F . G u l y a s s y , J . Clin. I n v e s t . 43, 2185 (1964). (61) R. A . L e v i n e , J . C l i n . I n v e s t . 5, 1039 (1966). (62) R. A. Levine and J . A. V o g e l , J . Pharm. E x p t l . Therap. 121, 262 (1966). (63) I . $ye, R . W. B u t c h e r , H. E. Morgan and E. W. S u t h e r l a n d . Fed. P r o c . 3 , 562 (1964). (64) R. A. Levine and J . A . Vogel, N a t u r e ?O], 987 (1965). (65) G . A. Robison. R. W . B u t c h e r , I . @yeie,H. E. Morgan and E. W . S u t h e r l a n d . Mol. Pharmacol. A, 168 (1965). (66) C . G. S m i t h , Annual R e p o r t s i n Med. Chem. (1965). (67) D i s c u s s i o n by E . W . S u t h e r l a n d and G. P. Talwar i n S c i e n c e 1 2 , 226 (1967).
m,
zs7,
m,
-
(68)
C.
G. Smith, R.
123 (1967). (69) R. S. Makman and (70) D. F. Ashman, R . corn.
A;,
(71)J .
(72)
C.
G.
C a r l s o n , G. D. Gray and A.
R . Hanze, Advances i n Enzyme Reg.
E . W . S u t h e r l a n d , J. B i o l . Chem. z#$O, 1309 (1965). L i p t o n , M. M. Melicon and T. D . P r i c e , Biochem. Biophys. R s .
330 ( 1 9 6 3 ) . G . Hardman and E. W . S u t h e r l a n d , J . B i o l . Chem. ? 4 9 , PC3704 (1965). G. S m i t h , H. H. B u s k i r k and W . L. Lummis, J . MeC. Chem., i n p r e s s (1967).
Section VI Topics i n Chemistry E. E. Smissman, University of Kansas, Lawrence, Kansas
Chapter 28 Synthetic Peptides George W. Anderson, Lederle Laboratories, American Cyanamid Company P e a r l River, New York Introduction. This review i s based on papers published i n 1966, and i s necessarily s e l e c t i v e i n order t o keep it s h o r t . Some of t h e newly proposed synthetic procedures a r e i n t e r e s t i n g but need f u r t h e r development. Only passing mention w i l l be given t o much important work i n the f i e l d of peptide hormones, since t h i s i s covered i n t h e chapter on non-steroidal hormones .
1 Books and Review A r t i c l e s . Schroder and Lubke have cmpleted t h e i r comprehensive survey with The Peptides, Vol. 11.Synthesis, Occurrence, and Action of Biologically Active Polypeptides. This work complanents t h e f i r s t volume (Methods of Peptide Synthesis) which appeared i n 1965, and the two a r e recoxtimended as t h e most cmprehensive treatise on peptides a v a i l a b l e today. A less cpprehensive b u t very readable Peptide Synthesis, by 3 Bodanszky and Ondetti a l s o appeared i n 1966, as did a monograph by Kopplg Peptides and Amino Acids, which was w r i t t e n f o r t h e use of undergraduate students of chemistry. Not t o be overlooked a r e general reviews by Wieland and Determann4 and Law5 on recent work, and more specialized reviews by Russell6 on Cyclodepsipetides and by S . G. Waley7 on Naturally Occurring Peptides. symposium on Hlypotensive Peptides, held i n 1965, w a s reported i n 1966.
8
Active Esters. The synthesis of r e a c t i v e e s t e r s of acylamino acids and t h e i r use in lengthening a peptide chain by reaction a t t h e amino end i s a j u s t i f i a b l y popular method; racemization i s avoided, y i e l d s are good, and p u r i f i c a t i o n of t h e products i s r e l a t i v e l y easy. Esters of N-hydroxysuccinimide (I), N-hydroxypiperidine (11) and 8-hydroxyquinoline (111) have received p a r t i c u l a r a t t e n t i Q n during 1966.
0 Q ACNHCHRCON
I
8-
r-\
AcNHCHR(!!O\
$
I1
I11
6
The p r a c t i c a l value of N-hydroxysuccinimide (HOSu) e s t e r s of acylamino a c i d s i s i l l u s t r a t e d by t h e i r use i n t h e syntheses of i n s u l i n ccnnponents
Chap. 28
Peptide s
Anderson
297 -
by t h e Aachen group. 9-15 Recent improvements of t h e mixed anhydride method16 have been ada t e d t o t h e synthesis of HOSu e s t e r s o f acylpeptides without racemization,lY which should g r e a t l y extend t h e u t i l i t y of these e s t e r s . The same communication reported t h e synthesis of N-hydroxypiperie s t e r s without racemization; however, t h e low r e a c t i v i t y of i s t o t h e i r disadvantage. The authors of t h e l a t t e r r e f e r ence found u s e f u l r e a c t i v i t y of HOPip e s t e r s of acyldipeptides with amino acid e s t e r s , but not with peptide e s t e r s . I n contrast, 8-hydromjquinoline (HOQ) e s t e r s of acylamino acids and acyldipeptides were found t o be highly r e a c t i v e t o amino acid o r peptide e s t e r s ; l 3 e s t e r s derived from 5-chloro8-hydroxyquinoline were even more r e a c t i v e .20 Since these e s t e r s a r e e s p e c i a l l y r e s i s t a n t t o racemization, they a r e promising. I l l u s t r a t i v e of t h e complexity i n evaluation of active e s t e r s , it has been observed t h a t the mixed anhydride procedure which gives a HOSu e s t e r without racemization y i e l d s a p a r t i a l l y racemized HCQ e s t e r . l T There a r e other indications t h a t HOSu has a good balance of properties f o r a c t i v e e s t e r use. Thus, it has been found t h a t t h e t r i f l u o r o a c e t a t e e s t e r s of p-nitrophenol, 2, 4, 5-trichlorophenol and HOSu a r e u s e f u l reagents f o r making t h e corresponding a c t i v e e s t e r s of acylamino acids, but o n l t h e The HOSu derivative gave l i t t l e racemization i n a s e n s i t i v e t e s t case." use of HOSu t o prevent racemization by t h e dicyclohexylcarbodimide method, which l i k e l y proceeds v i a t h e a c t i v e e s t e r s , w i l l be discussed below. Finally, an ingenious synthesis of t-butyloxycarbonylamino a c i d s v i a t-butyloxycarbonyl N-hydroxysuccinimide e s t e r and t h e subsequent i n s i t u synthesis of t-butyloxycarbonylamino acid N-hydroxysuCcinimi.de e s t e r s i s noted.22 *
An improved procedure f o r t h e use of t-butyloxycarbonylanino acid p-nitrophenyl e s t e r s i n s o l i d phase synthesis of peptides was r e p 0 r t e d . ~ 3 An opposite procedure, i n .which t h e a c t i v e e s t e r tias attached t o a r e s i n , w a s investigated i n two l a b o r a t o r i e ~ ~ ~ fju~r 5 t h;e r work w i l l be necessary t o evaluate t h e u t i l i t y of t h i s approach. More evidence t h a t commonly used a c t i v e e s t e r s can be used without racemization was found by Weygand, B o x and Konig.26 Their t e s t , which involved t h e coupling of Z*Leu-Phe.OH (2L) w i t h H . V a l . O t 'Bu, was applied t o a number of common methods; only t h e azide and t h e a c t i v e e s t e r s gave no racemate. However, Liberek blichalik27 have found t h a t racemization H-Gly-OEt; t h i s i s an unusual case, occurs i n coupling of Z - a l a but it i l l u s t r a t e s t h a t no absolute conclusions can be drawn. Mixed Anhy dride Coupling. This very popular method, involving t h e use of alkyl chloroformates as reagents t o make anhydrides with acylamino acids or acyl eptides, has been reinvestigated. Determann, Heuer, Pfaender and Reinartz28 have shown t h a t exposure of the mixed anhydride
8
X-Phe.0 O q C H 3
t o triethylamine gives racemization r a t e s i n the order
benzoyl' a c e t y l ? formyl f o r X; no racemate was found when X was ethoxycarbonyl o r t-butyloxycarbonyl. These r e s u l t s confirn previous findings, and an azlactone mechanism of racemization. Anderson, Zinnr,eman
S e c t . VI - Topics i n C h e m i s t r y
298 -
S m i s s m a n , Ed.
and Callahan16 presented evidence for t e r t i a r y m i n e p a r t i c i p a t i o n i n mixed anhydride formation, with s t e r i c f a c t o r s being important. Racemization could be avoided i n s e n s i t i v e t e s t cases by use of a t e r t i a r y m i n e containing an N-methyl group, provided no excess was used. With a s u i t a b l y weak m i n e such a s N-methylmorpholine, an excess w a s permissable. Coupling of acylpeptides without racemization should now be p o s s i b l e , which w i l l considerably extend t h e u t i l i t y of t h e mixed anhydride method.
DicYclohexYlcarbodiimide ( E C D ) Coupling. This method was improved by ?Tiinsch and Dreeszy and Weygand, Hoffmann and F:iin~ch3~. The first authors found t h a t t h e a d d i t i o n of an equivalent or more of N-hydroxysuccinimide t o t h e coupling of a C-terminal l e u c i n e pentapeptide t o a t r i p e p t i d e e s t e r i n t h e presence of DCCD r a i s e d t h e y i e l d from 31% t o 75% and eliminated t h e N-acylurea byproduct. The l a t t e r authors found t h a t racemization i n t h e s y n t k e s i s of Z-Leu-Phe-ValeOtBu from Z-Leu-Phe-OH and H.Val-OtBu by DCCD was eliminated by using two equivalents of H@Suand a temperature of - 2 2 " . Since an excess of DCCD was a l s o used, t h e minimum requirements f o r no rncemization were not c l e a r . p->:itrophenoi i n place of EICEu d i d not e l - b i n a t e racernization. I n another paper31, it xas found thak t h e coupling of pi.5: .Leu-Phe. OH(where gIGZ i s g-methoxybenzyloxycarbonyl) t o H.Val-OCK2*P (where P i s a polymer) i n dhethylformamide a t room t e n p e r a t w e i n t h e presence of HOSu ( 2 e q u i v a l e n t s ) and. DCCD gave sorne racemization, b u t a similar r e a c t i o n i n methylene c h l o r i d e gave none. The use of o p t i c a l l y pure f'1vE.Leu-Val.OSu a l s o gave no racemate. The i m p l i c a t i o n i s t h a t racemization-free DCCD r e a c t i o n a l s o proceeded through t h e HoSu e s t e r , b u t it i s nof proven. I n :.rork r e p o r t e d a t a synposium i n
1965 b u t
published i n
196G8
BZl
?Bzl Katchalski r e p o r t e d good r e s u l t s i n t h e s y n t h e s i s of BOC .T$r-Ua-Glu.OSu by t h e DCC3 method, removal of p r o t e c t i n g groups and polymerization. In r e t r o s p e c t it seems l i k e l y t h a t r a c e n i z a t i o n d i d not occur. Rapid S y n t h e t i c Procedures. T'ne most i n t e r e s t i n g development of t h e year pias t h e s k i l l f u l use of a - a z i n o a c i d N-carboxyanhyd.rides i n a r a p i d s y n t h e s i s i n aqueous medium3*. This procedure i s much f a s t e r t h a n t h e I t e r r i f i e l d " s o l i d phase" s y n t h e s i s , undoubtedly more econornical, and mobably e a s i e r t o adapt t o l a r g e r scale syntheses. It appears t h a t more byproducts a r e formed, b u t both methods r e q u i r e cnroniatographic or more e l a b o r a t e p u r i f i c a t i o n of -the f i n a l products. iiie " s o l i d phase method was f u r t h e r applied during t h e year by M e r r i f i e l d and a s s o c i a t e s . The most severe t e s t was i t s use fcr t h e s y n t h e s i s of t h e A and B chains of insulin33; it i s not p o s s i b l e t o a c c u r a t e l y e v a l u a t e t h e r e s u l t s from t h e b r i e f r e p o r t , b u t i n s u l i n a c t i v i t y :..-asobtained by o x i d a t i v e combination of t h e two chains. I n another g a p e r 3 it 1;ra.s s h o m by sTynthesis of bradykinylbradykinin, an 18 anino a c i d pepti.de, t h a t t h e o-nitrophenylsulfenyl group can be used f o r amine p r o t e c t i o n i n t h i s g o c e d u r e . The automated solid-phase s y n t h e s i s of t h e C-terminal decapeptidc fraLment of tobacco mosaic v i r u s p r o t e i n was r e p o r t e d by Stewart, Young, Benjaiiini, Shimiza and Leung35. rl1
'
Chap. 28
Peptide s
Anderson
299 -
Amine-Frotectirl@;Groups. The 0-nitrophenylsulfenyl (NPS) group, introduced i n 19633O, received a good deal of a t t e n t i o n during t h e year. Selective removal i n the presence of ccamnonly used groups such as benzyloxycarbonyl and t-butyloxycarbonyl (BOC) i s a p a r t i c u l a r l y desired property, and t h e NPS group has been promising f o r t h i s use. From comparative syntheses of a decapeptide, Poduska37 concluded t h a t selective removal of the NPS group by hydrogen chloride with BOC as the "stable" group was r i s k y i n long syntheses. Kessler and Iselin38 reached similar conclusions; they found p r m i s i n g r e s u l t s with thioacetamide i n t h e presence of a c e t i c acid, although byproducts f r o m t h e NPS caused some d i f f i c u l t i e s . Brandenburg39 found t h a t acidolysis i n t h e presence of mercaptoethanol helped avoid unwanted byproducts. Fontana e t a1.40 reccmnnend thiophenol or thioglycollic acid. Further work41 with t h e t-amyloxycarbonyl group showed t h a t it i s comparable t o t h e t -butyloxycarbonyl group. The furfuryloxycarbonyl group was found t o be between t h e t-butyloxycarbonyl and benzyloxycarbonyl groups i n ease of removal by acid treatment.42 Carboxy-Protecting Groups. Stewart43 has investigated 2, 4, 6trimethylbenzyl e s t e r s . They are comparable t o t - b u t y l e s t e r s i n s e n s i t i v i t y t o acid catalyzed cleavage. Methanolic hydrogen chloride does not a f f e c t them under conditions which remove NPS or t r i t y l groups. Further work with diphenylmethyl, wc phenacylu, and f3-rnethylthioethy14~ e s t e r s disclosed useful combinations with N-protecting groups, p a r t i c u l a r l y t r i t y l and o-nitrophenylsulfenyl groups. Special Protecting Groups. I n t h r e e papers 46,47y48 Hiskey and coworkers reported a study of t h e problem of SH protection i n the synthesis of cysteine peptides. Mercuric acetate was found t o be useful f o r &elective cleavage of the S-triphenylmethyl groups, and sodium ethoxide f o r the S-benzoyl group. The l a t t e r group i s limited i n u t i l i t y , however, because of tende cy t o migration t o the amino group during peptide bond formation. Guttmann 9 found t h a t a new S-protecting group, e t h y l carbanoyl (CH3CH2NHCO-), was stable under acidic and n e u t r a l conditions but readily cleaved by basic reagents. glutathione and oxytocin were synthesized with i t s use. Wilchek e t al.3O solved the problem by synthesizing peptides containing L-p-chloroalanine and converting these t o cysteine peptides with appropriate t h i o compounds.
t
Weygand and a s s 0 c i a t e s 5 ~introduced a new protecting group f o r t h e imidazole of histidine, 2, 2, 2-trifluoro-1-benzyloxycarbonylaminoethyl(m); it i s r e s i s t a n t t o acid and t o alkali, and i s cleaved by hydrogenation, then hydrolysis. FGCH-
dH3
(rv) z-TFgroup
(v) D m
&COUP
Y
U
( V I ) phthalimidomethyl
30 0 -
Sect. VI - Topics i n C h e m i s t r y
Smi s sman, Ed.
Weygand e t a1.52 a l s o proposed t h e 2, bdimethoxybenzyl group (V) f o r protection of amide groups; perhaps t h e most i n t e r e s t i n g aspect of such amide protection i s t h e r e s u l t i n g increase i n s o l u b i l i t y of peptides i n organic solvents. The group i s removed by strong acid treatment or by sodium i n l i q u i d ammonia. Wilchek e t a1.53 found t h e phthalimidamethyl group ( V I ) t o be u s e f u l f o r protecting t h e y-carboxyl of glutamic acid; it was removed by molar piperidine. Biological A c t i v i t y of Synthetic Peptides. The primary reasons f o r t h e synthesis of peptides a r e t o confirm s t r u c t u r e s of biologically a c t i v e natural peptides and t o study t h e e f f e c t of modification of such s t r u c t u r e s on t h e b i o l o g i c a l e f f e c t s . A p r a c t i c a l goal i s t h e synthesis of peptides which can be used f o r drug purposes. Progress i n these areas was made i n
1966. Much work on t h e synthesis of hormones and analogs was reported, and t h i s w i l l be covered i n another chapter as already mentioned. A c p l e t e r e p o r t on t h e syntheses of p-corticotropins by Schwyzer and S i e b e r T i s noted here; t h i s i s of general i n t e r e s t because of t h e discussion of problems i n synthesis and p u r i f i c a t i o n of products. An analog of a 25 amino acid corticotrophin (ACTH) fragnent with improved properties f o r drug use was reported??; r e s i s t a n c e t o aminopeptidase a c t i v i t y by proviaing a D-serine residue a t t h e amino end and t o carboxypeptidase by a C-terminal mlinamide, and r e s i s t a n c e t o a i r oxidation by s u b s t i t u t i n g norleucine f o r methionine were obta'ned. Biological assays showed increased potency over natural ACT$ ?t and more prolonged a c t i o n i n human beings57. These r e s u l t s suggest t h a t synthetic v a r i a t i o n s w i l l be valuable i n improving t h e medical properties of other b i o l o g i c a l l y a c t i v e peptides.
,
Replacement of amide by e s t e r linkages gives a c l a s s of cmpounds known as depsipeptides. A n example i s t h e cyclic a n t i b i o t i c valinamycin (VII) J A
I-
- - -----(D-Val-L-Lac-L-Val-D-mIv)
3
VII which i s composed of valine, l a c t i c a c i d andCZ-hydroxyisovaleric acid u n i t s I n a paper of s p e c i a l interest58, Shemyakin and associates showed t h a t replacement of one of t h e hydroxy acids with a sirnilas amino acid gave compounds with a n t i b i o t i c a c t i v i t y which i n sane cases exceeded t h a t of t h e n a t u r a l compound. Similarly, replacement of amide by e s t e r groups t o give analogs of glutathione, ophthalmic acid and bradykinin gave b i o l o g i c a l l y a c t i v e compounds. Resistance t o enzymatic a t t a c k i s one of t h e i n t e r e s t i n g p o s s i b i l i t i e s of such compounds.
Replacement of amino acid moieties i n b i o l o g i c a l l y active peptides by other amino acids with r e t e n t i o n of a c t i v i t y i s cannon, and more examples were reported during t h e year. A p a r t i c u l a r l y i n t e r e s t i n g study w a s made
Chap. 28
Peptides
30 1 -
Anderson
by Hof’mann and Bohn.59 Histidine appears t o be important i n t h e biological a c t i v i t y of several enzymes and hormones, probably because of the acid-base behanior of i t s imidazole f’ragment. Hof’mann and Bohn replaced t h e h i s t i d i n e of an S-peptide fragment of ribonuclease with 8- (pyrazole-1)-Lalanine and with B -(ppazole-3)-L-alanine; although these are i s o s t e r i c with h i s t i d i n e , b i o l o g i c a l a c t i v i t y was l o s t . Since t h e pyrazoles d i f f e r i n acid-base properties, t h e r e s u l t s suggest t h a t t h e ionization behavior of h i s t i d i n e i s important i n t h e a c t i v a t i o n of ribonuclease S-protein by S -pept ide .
I n t h e a n t i b i o t i c f i e l d , Vogler and StuderGO have reviewed t h e chemistry of t h e poly-myxin a n t i b i o t i c s . Studer, Lergier and6pgler61 reported t h e synthesis of Circulin A, and Ohno and coworkers synthesized tyrocidin A. References
1. E. Schroder and K. Lubke, The Peptides,
z.
Synthesis, Occurrence, and Action of Biologically Active Polypeptides. Translated by E. Gross. Academic Press Inc. U.1 F i t h Avenue, New York, New York, 1966. M. Bodanszlry and M. A. Ondetti, Peptide Synthesis. Interscience Publishers, New York, New York, 1966. K. D. Kopple, Peptides and Amino Acids, W . A. Benjamin, Inc., New York, New York, 1966. T . Wieland and H. Determann, Ann. Rev. Biochemistry, 35 ( 2 ) , 651 (1966) H. D. Law, Amino-Acids and Peptides, Ann. Reports, 62,389 (1966). D . W. Russell, Cyclodepsipeptides, W a r t . Rev., 2 0 , 5 5 9 (1966). S. G . Waley, Naturally Occurring Peptides, Adv. Protein Chem., 21,
,
2.
3.
4. 5. 6. 7. 8.
-
1, (1966) *
E. G. Erdss, N. Back, F. S i c u t e r i and A. F. Wilde, Eds., Hypotensive Peptides, Springer-Verlag, New York, New York, 1966. 48, 171 (1966). 9. J.Meienhofer, Acta Chim. Acad. S c i . Hung., 10. J . Meienhofer, Ann. Chem., 692, 231 (1966). 11. E. Schnabel, Ann. .Chem., 220 (1966). 12. M. Kinoshita and H. Klostermeyer, Ann. Chem. 696, 226 (1966). 13. M. Kinoshita and H. Zahn, Ann. Chim., 696, 234-966). 14. K . B. Mathur, H. Klostermeyer and H. Z Z , Z . Physiol. Chem., 346, 60
,
(1966) *
15.
16.
17*
H. Z a n y W. Danho and B. Gutte, Z . Naturforschung,, g, 763 (1966). G. W. Anderson, J. E . Zimmerman and F. 14. Callahan, J. Am. Chem. SOC.,
88,
1338 (1966).
G. W. Anderson, F. M. Callahan and J. E . Zimerman, J . Am. Chem. SOC.,
89, 178 (1967).
18. F. Weygand, 19.
20. 21. 22.
W. Konig, E. Nintz, D. Hoff’mann, P. Huber, N. M. Khan and W. Prinz, Z . Naturforschung, 21b, 325 (1966). H. - D. Jakubke and A. Voight3hem. Ber 3, 2419 (1966) H. - D. Jakubke and A. Voight, Chem. Ber . 2944 (1966). S . Sakakibara and N. Inukai, B u l l . Chem. SOC. Japan, 39, 1567 (1966). M. Frankel, D. Ladkany, C . Gilon and Y. Wolman, T e t r a r m o n L e t t e r s No. 39, 4765 (1966).
.,
, By
.
Sect. VI
30 2
-
Topics i n C h e m i s t r y
23-
Smi s sman, Ed.
14. Bodanszw and J. T. Sheehan, Chem. & Ind., 1966, 1597. 24. M. Fridkin, A. Patchornik, and E. Katchalski, Chem. Soc., 88,
n.
3164 (1966).
25. T . Kieland and C . B i r r , Angew. Chem. ( I n t e r n a t . Ed), 2, 310 (1966). 26. F. Weygand, A. &ox and bi. Konig, Chem. Ber. 99, 1451 (1966). 27. B. Liberek and A. Michalik, Roczniki Chemii G. SOC. Chim. Polonorum
28.
40, 597 (1966) H. Determann, H. Heuer, 694, 190 (1966).
29. 30.
E . Wihsch and F. Drees, Chem. Ber., F . bieygand, D. Hoffmann and E. Whsch,
*
P. Pfaender and M. - L. Reinartz, Ann. Chem.,
z, 110 (1966).
Weygand and V.
Z . Naturforschung,
g, 426
(1966)
Ragnarsson, Z . Naturforschung, 21b, ll41(1966). F. R . G. Denkewalter, H. Schmn, R . G . Strachan, T . T B e e s l e y , D. F . Veber, E . F . Schoenewalt, H. Barkemeyer, W. J . Paleveda, Jr T. A. Jacob, and R . Hirschmann, J. Am. Chem. SOC. 88, 3163 (1966). A. IAarglin and R . B. Merrifield, J. Am. Chem. Soc., 88, 5051 (1966). V . A. Najjar and R . B. Merrifield, Biochemistry, 5, 3765 (1966). J . M. Stewart, J. D . Young, E. Benjamini, 14. Shimizu -.nd C . Y. Leung, Biochemistry, 5, 3396 (1966). L . Zervas, D. Borovas and E . Gazis, J. Am. Chem. Soc., 85, 3660 (1963) K. Poduzka, Collection Czechoslov. Chem. C m u n . , 31, 255 ( 1966 ) . W. Kessler and B. I s e l i n , Helv. Chim. Acta, 49, 133 (1966). D . Brandenburg, Tetrahedron Letters, 6201. A. Fontana, F. Marchiori, L. Moroder, and E. Scoffone, Tetrahedron Letters, 2985. S . Sakakibara and M. Fujino, Bull. Chem. SOC. Japan, 3, 947 (1966). H. Jeschkeit, G. Losse and K. Menbert, Chem. Ber., 99, 2803 (1966). F. H. C . Stewart, Australian J . Chem., 9, 1067, 1511 (1966). G. C . Stalakatos, A. Paganou, and L. Zervas, J . Chem. SOC., ( C )
,
33. 34. 35.
36. 37. 38. 39.
40. 41. 42.
43.
44.
.,
1966,
1966,
1966, 1197.
45. 46. 47. 48. 49. 50.
M. Joaquina S. A. A m a r a l , G. C . Barrett, H. N . Rydon and J. E . Willett J . Chan. SOC. ( C ) , 807. R . G. Hiskey, T . Mizoguchi and H. Igeta, J . Org. Chem., 2,U88 (1966) R. G. Hiskey, T . Mizoguchi and T . Inui, J . Org. Chem., 2,1192 (1966) R . G. Hiskey and J. B. Adams, Jr., J. Org. Chem., 3,1192 (1966). S. Guttmann, Helv. Chim. Acta, 83 (1966). 14. Wilchek, C . Ziondron, and A. Patchor:iik, J. Org. Chem., 3,2865
53.
F . Weygand, F. Weygand, Tetrahedron M. GJilchek,
1966,
9,
(1966) *
W. S t e g l i c h and P. P i e t t a , Tetrahedron Letters, 1966,3751. W . Steglich, J. Bjarnason, R . Akhtar and N. M. Khan,
Letters,
1966, 3483.
A. Frensdorff and M. Sela, Arch. Biochem. Biophys., 113
742 (1966). 54. R. Schwyzer and P. Sieber, Helv. Chim. Acta, 49, 134 (1966). 55. R . A. Boissonnas, S t . Guttmann and J. Pless, Ekpebentia, 22, 526 (1966) 56. :!. Doepfner, Experientia 22, 527 (1966). 57. M. Jenny, A. F . Muller and R . S . Mach, Experientia 22, 528 (1966). 58. 1.1. 14. Shemyakin, L. A . Shchukina, E. I . Vinogradova, G. A. Ravedel and Yu. A. Ovchinnikov, Experientia 22, 535 (1966).
Chap. 28
Peptides
Anderson
30 3 -
59. K. Hofknann and H. Bohn, J . Am. C h e m . SOC., 88, 591'1. (1966). 60. K . Vogler and R . 0. Studer, m p e r i e n t i a 2 2 , 3 4 5 (1966). 61. R . 0 . Studer, W. Lergier and K. Vogler, Helv. C h i m . A c t s , 49, 974 (1966 1 62. 14. Ohno, T . Kato, S . Makisumi and It. Izumiya, B u l l . C h e m . SOC. Japan, 3, 1738 (1966).
30 4 Chapter 29. Nucleosides and Nucleotides Howard J . Schaeffer, State University of New York at Buffalo, Buffalo, New York During 1966, a review of methods in nucleoside syntheses' and a review of the ionization and metal complex formation of adenosine and adenine nucleotides were published. 2 The preparation of nucleosides by the fusion method continues to be employed extensively. Iodine has been found to be a good catalyst for the synthesis of certain nucleosides by the fusion method? Nebularine has been synthesized in high yield by the fusion technique using &-@nitropheny1)hydrogen phosphate as the catalyst .4 The synthesis of 2'-Cmethyladenosine has been accomplished from the protected 2-C-methyl-Dribono-7-lactone (I) which was reduced with &-(3-methyl-2-buty1)borane(disiamylborane). The corresponding tetrabenzoyl derivative was converted into the chloro sugar which after condensation with chloromercuri-6-benzamidopurine followed by deblocking gave 2 '-C-methyladen~sine.~ This compound as well as 3'-C-methyladenosine are both cytotoxic against KB cells in ~ u l t u r e . ~ Nucleosides were prepared by the fusion method from homoribose with 6-chloro-, and 2,6-diI chloropurines. The corresponding 6-mercaptoand 2-chloro-6-aminopurinenucleosides were nontoxic in tissue culture (KB and HEp-2/MP).6 A variety of aldofuranosyl nucleosides have been prepared by the chloromercuri procedure.' The utilization of the 2,4-dinitrophenyl group as a blocking group in the preparation of 2'-amino-2'deoxy-nucleosides has been described in the synthesis of 2'-amino-2'deoxy-adenosine. Urbas and Whistler have prepared several 1- (4-thio-Dribofuranosy1)pyrimidine nucleosides by the Hilbert-Johnson procedure. In all instances a 2:l mixture of anomers was obtained with the f3-2 anomer predominating over the a-2 anomer. The synthesis of 4'-acetamidoadenosine has been accomplished by the condensation of 4-acetamido-1,5-di-O-acetyl2 ,3-di-0- benzoy l-4-deoxy-D -ribofuranose with chloromercuri-6-benzamidopurine using a titanium tetrachloride catalyzed reaction. lo 1-Deaza-6-methylthiopurine ribonucleoside and 3-deaza-6-methylthiopurine ribonucleoside have been prepared by fusion of the corresponding deaza-6-chloropurine with t e t r a - 0 - a c e t y l r i b o f u r a n o s e followed by reaction with sodium methyl mercaptide.11,l2 Both of these deaza nucleosides were much less cytoxic than 6-methylthiopurine ribonucleoside, but l-deaza6-methylthiopurine ribonucleoside was cytotoxic to HEp-2 cells which were resistant to 6-merca topurine. 3-Deazaadenosine has been synthesized by a related procedure.P3 Replacement of the 6-chloro group could not be accomplished with ammonia. However, treatment of 3-deaza-6-chloropurine ribonucleoside with hydrazine followed by reduction with Raney nickel gave 3-deazaadenosine . 13
Montgomery and Thomas have studied the infrared, ultraviolet and NMR
Chap. 2 9
Nucleosides and Nucleotides
Schaeffer
30 5 -
spectra of a number of mercury or chloromercury purines and compared these spectra with the spectra of the corresponding sodium s a l t s and N-7 and N - 9 a1kylp~rines.l~Based on these studies, they concluded that the mercury or chloromercuri are covalent. The chloromercury group is attached to N-7 of 3-benzylhypoxanthine and the mercury group is at N-7 of theophylline. The chloromercuri group is attached to N-9 of l-benzylhypoxanthine, 1-benzylpurine-6(1 H) -thione, and 6-dimethylaminopurine. When these mercury or chloromercury derivatives are allowed to react with acylglycosyl halides the attack is on the nitrogen bearing the mercury or chloromercury group. 14 The utility of a 3-substituent on hypoxanthine to direct substitution to the 7-position has been shown by the preparation of 7a- and 7B-D-arabinofuranosylhypoxanthines. l5 Thus , 3-benzyl- o r 3-benzhydryladenines were treated with nitrosyl chloride to give the corresponding 3-substituted hypoxanthines. The chloromercury derivatives of these compounds were condensed with 2,3,5-tri-O-benzoyl-D-arabinofuranosyl bromide. Catalytic hydrogenolysis of the benzyl or benzhydryl group gave 7a- and 7B-D-arab i n o f u r a n o s y l h y p o x a n t h i n e s . l5 The synthesis of 7-glycosylpurines as the exclusive product of the reactions is exemplified by the preparation of 7B-D-ribofuranosyladenine.16 4 (5) -Bromo-5(4)-nitroimidazole was fused with tetra-0-acetyl-@-D-ribofuranose to give a N-glycosyl derivative which on treatment with potassium cyanide, then Raney nickel and finally with acetic anhydride and triethyl orthoformate gave 7-B-D-ribofuranosyladenine.16 Shimizu and Miyaki have shown that the migration of the ribosyl group in N-benzoyl-3-~-D-ribofuranosyLadenine from N 3 to N 9 occurs by an intermolecular mechanism. 17 An interesting stereoselective synthesis of the anomeric 5-mercapto-2'deoxyuridines has recently been reported. l8 When 5-acetylmercapto-2,4-0bis-(trimethylsily1)uracil and the blocked chloro sugar were fused at 100110" for 15-20 minutes, only the B-isomer of the blocked compound could be isolated from the reaction. However, when the reaction was carried out in benzene solution at 37" for 90 hours, only the a-isomer was isolated.18
By modifications of known procedures, the following compounds have been prepared: 1-B-D-arabinofuranosylthymine, l9 2 '-deoxy-5-(trifluoromethyl) uridine and its a-anomer,2o a- and @-5-trifluoromethyl-6-aza-2'-deoxyuridines,21,2 2 l-~-D-arabinofuranosyl-5-fluorouracil, 23 5-fluoro-2'deoxycytirimidines,25 pyrLmidine and urine nucledine,24 3'-deoxynucleosides of 9-D-mannofuranosyladenine, 2f; 3-@-D-araosides of D-glucuronic acid,26,'y b inofuranosyladenine, 3-B-D- ribofuranosy lor0t ic ac id,30 5- (DLribofuranosyl) -6-azauracil,31 and 5-a-D-arabinitoluracil and 5-a-D-ribitoluracil.32 Chemical transformations of nucleosides have resulted in the syntheses of some 2',3'-unsaturated pyrimidine nucleosides33 as well as a 4',5'unsaturated pyrimidine nucleoside.34 Treatment of 3'-0-tosyl-2'-deoxyadenosine with alkoxide produced the 2' ,3'-unsaturated n u ~ l e o s i d e36 ~ ~ as , well as a smaller amount of the 3',5'-oxetane deri~ative.3~The syntheses of 2 ' ,3'-dideoxy-, 2 ' ,5 ' -dideoxy-, and 2 ' ,3',5 '-trideoxyadenosine have been accomplished by mono- or ditosylation of 2'-deoxyadenosine
306 -
Sect. VI
-
Topics in Chemistry
Smi s sman, Ed.
'0 HoxoHp - I2
followed by displacement of the tosylate with sodium ethyl mercaptide and Raney nickel desulfurization.37 F\c L O O H
H
o
~
0 o
I'H~
A novel transformation
in aqueous alkali has been observed with 1-f3-D0 uracil arabinof as uranos outlined.38 yl-5 fluoroThe
-
open cham compound was isolated in 50% yield and by treatment with diazomethane and then with alkali generated 1- f3-D -arabinofuranosyl-3-methyl-5fluorouracil. Moreover, the ribo- or 2'-deoxyribo derivatives did not undergo this reaction.38 The acid catalyzed solvolysis of pyrimidine nucleosides has been studied and the acid stability is markedly influenced by the number o f hydroxyl groups in the sugar. In the 2'-deoxyribonucleosides, the 3'-hydroxyl group exhibits a large effect on the rate of react i ~ n ? A~ convenient synthesis y f 1;p-D-arabinofuranosylcytosine has been reported by tosylation o f ~ 4 , 0 3,O5 -tri-0-acetylcytidine. The proposed 2,2'-anhydrocytidine derivative undergoes rapid hydrolysis to 1-f3-Darabinofuranosylcytosine.40 Hampton and Nichol have described a convenient synthesis of 2,2'-anhydro-l-~-D-arabinofuranosyluracil by treating uridine with diphenyl carbonate.41 In a continuation of some studies on acyl migrations in model compounds related to aminoacyl-S-RNA, a technique has been developed using NMR to determine the rate of acyl migration in some 3'-O-acyl ribonucleosides. It was estimated that the half-time of equilibration into 2' and 3'-isomers of an average aminoacyl-S-RNA derivative in pH 7 buffer at 37' sec. It was concluded that equilibration of an average aminois 2 x acyl-S-RNA would most likely be much faster than peptide bond synthesis.42 Two studies of ORD on pyrimidine nucleosides have appeared which assist in the assignment o f the anomeric configuration.43,44 The anomeric configuration can be assigned utilizing an NMR technique which compares the pyrimidine nucleoside with its 5,6-dihydroderivative.45 In some 6-substituted purine 3'-deoxyribonucleosides,a direct correlation between the extent of phosphorylation of the nucleosides and inhibition of RNA synthesis in intact Ehrlich ascites cells has been shown.46 The synthesis and properties o f some substituted 6-hydroxylaminopurines has been de~cribed.~7 The structures of f ~ r m y c i n , formycin ~~ B,48 and blasticidin S4' have been described. The syntheses of some nucleosidic peptides related to amicetin have also been reported.50 In an elegant paper, Shealy and Clayton have outlined their synthesis of 9G-DL-2a, 3a-dihydroxy-4P-(hydroxymethyl) cyclopentyl] adenine (11)
Chap. 29
Nucleosides and Nucleotides
HO
OH I1
S cha effe r
307 -
which is the carbocyclic analog of adenosine.51 Norbornadiene was cis-hydroxylated and after protection the olefin was oxidized to yield 2a,3adiacetoxy-l~,4f3-cyclopentanedicarboxylicacid. The cyclic anhydride was converted into the amide acid which on Hofmann rearrangement followed by lithium borohydride reduction on the ester gave a derivative of l~-amino-2a,3a-dihydroxy-4B-hydroxymethylcyclopentane. Condensation of the aminotr iol with 5-amino-4,6-dichloropyrimid ine followed by ring closure with triethyl orthoformate gave the 6-chloropurine derivative which on treatment with ammonia gave II.51
A most unusual rearrangement has been observed by Chheda and Hall with the finding that N6-glycvladenine (111) is converted into N- (6-purinyl) When 111 is kept in aqueous solution for a few minutes glycine (vII),~~ at lOO", it loses the elements of ammonia and forms a cyclic intermediate which has beep assigned structure IV. N6-chloroacetyladenine (V) forms the identical intermediate(1V). Compound IV in neutral solution undergoes ring cleavage, and rearrangement to VII, presumably via VI.52 0
NHCOCH2NH2
H
I," /
H
H V
111
H VI
VII
The initial announcement of a method for the stepwise synthesis of o l i g o d e o x y r i b o n u c l e o t i d e s on aninsoluble polymer support was made in 1965 by Letsinger and M a h a d e ~ a n . ~ n~ 1966 several papers appeared on syntheThe procedure used by Letsinger and ses with a polymer support.54-5' Mahadevan employs an insoluble copolymer of styrene (88%); 2-vinylbenzoic acid (12%) and p-divinylbenzene (0.2% or 0.02 %). The carboxyl groups on the polymer were converted into acid chlorides with thionyl chloride and allowed to react with 5 '-0-trityl-2'-deoxycytidine (VIII) to yield IX. Condensation of IX with cyanoethylphosphate and mesitylenesulfonyl chloride or DCC gave X. When X was activated with mesitylenesulfonyl chloride and
30 8 -
Sect. VI
- Topics
in Chemistry
Smi s sman, Ed.
condensed with thymidine XI was produced. By repetition of 'the phosphorylation of the free 3'-hydroxyl group, activation and condensation steps several different oligodeoxyribonucle@-co-NH otides were synthesized. The final products can be removed from the polymer with 0.4 M_ sodium hydroxide in a mixture of dioxane, ethanol and 0 water .53354 0
" 4
The second method of deoxyribonucleotide synthesis on a polymer support is different from the procedure of Letsinger and Mahadevan in two respects. The polymer employed is a polystrene polymer which is soluble in the reaction medium and the deoxyribonucleoside is attached to the polymer through its 5I-hydroxyl group by means Ok of a methoxytrityl group on the polymer.55,56 In order to functionalize XI the polymer (XII), it was subjected to a Friedel-Crafts with benzoyl chloride to give XIII. Treatment of XI11 with 2-methoxyphenylmagnesium bromide gave the trityl alcohol (XIV) which was converted to the trit 1 chloride (XV) with acet 1 chloride. Condensation of XV with thymidineT5 or 3I-O-acetylthymidineX6 gave XVI. For internucleotide bond synthesis, XVI was allowed to react with pyridinium 3'-O-acetylthymidine 5 -phosphate and mesitylene chloride in pyridine solution. After treatment with water followed by removal of the 3I-O-acetyl blocking group, XVII was obtained in good yield. By repetitimof the condensation and deblocking steps, several different oligodeoxyribonucleotides were prepared. Removal of the oligodeoxyribonucleotide from the polymer was accomplished by brief treatment with trifluoroacetic acid in chloroform55 or d i ~ x a n e . ~ ~ A review has appeared on the synthesis and biological function of nucle~ t i d e s . A~ ~ paper describing the synthesis of the 64 possible ribotrinucleotides derived from the four major ribomononucleotides has been
Chap. 2 9
Nucleosides and Nucleotides
XI1
XI11
Scha effer
30 9 -
p~blished.5~A report has appeared describing the use of nucleoside 2’-0benzyl ethers in the synthesis of oligoribonucleotides.59 The use of l-dimethy lamino-1,1-dialkoxymethanes as a blocking group for reactive amino groups of cytidine, adenosine and guanosine in the stepwise synthesis of ribooligonucleotides has been described.60
Detailed kinetic studies on internucleotide bond synthesis using arylXIV, R=OH sulfonyl chlorides are reported, and the XV, R=C1 use of 2,4,6-triisopropylbenzenesulfonyl chloride for internucleotide bond synthesis is described.61 Phosphorylation of nucleosides with organic amine salts of phosphoric acid has been
XVI
XVII
studies on the preparation of nucleotides and ~ t u d i e d . ~ ~Additional >~3 dinucleoside phosphates by the anhydronucleoside method have been reported. 64965 Finally, an interesting phosphorylation of ribonucleosides with phosphorus trichloride has been discovered.66 Reaction of 2 ’ , 3’-O-isopropylidene inosine with phosphorus trichloride in acetone solution followed by an aqueous treatment and removal of the blocking group gave 5’-IMP in a 91% yield. This reaction was applicable to other nucleoside isopropylidene derivatives. The reaction requires oxygen and a solvent which is a ketone or aldehyde (acetone and methyl ethyl ketone are best). It is postulated that phosphorus trichloride reacts with the nucleoside to6give a dichlorophosphite which is then oxidized to the dichlorophosphate.
310 -
Sect. VI
-
T o p i c s in C h e m i s t r y
Smi s sman, Ed.
References
(1) H. G . Garg, J . S c i . Ind. Research 25, 404 (1966). (2) R. P h i l l i p s , Chem. Rev. 66, 501 (1966). (3) K . I m i a , A. Nohara and M. Honjo, Chem. Pharm. B u l l (Tokyo) E, 1377 (1966). (4) T. Hashizume and H. Iwamura, T e t r a h e d r o n L e t t e r s 643 (1966). (5) E. Walton, S. R. J e n k i n s , R . F. N u t t , M. Zimmerman and F. W . H o l l y , J. Am. Chem. Soc. 88, 4524 (1966). (6) J. A. Montgomery and K. Hewson, J . Med. Chem. 2, 234 (1966). (7) P . Kohn, R. H. S a m a r i t a n 0 and L. M . L e r n e r , J . Org. Chem. 31, 1503 (1966). (8) M. L. Wolfrom and M. W . Winkley, Chem. Comm. 533 (1966). (9) B . Urbas and R. L. W h i s t l e r , J. Org. Chem. 31, 813 (1966). (10) E. J. R e i s t , D. E. Gueffroy, R. W. Blackford and L. Goodman, J . Org. Chem. 3l, 4025 (1966). (11) J. A. Montgomery and K. Hewson, J . Med. Chem. 2, 354 (1966). (12) J. A. Montgomery and K. Hewson, J . Med. Chem. 2, 105 (1966). (13) R. J. Rousseau, L. B. Townsend and R. K. Robins, Biochemistry 5, 756 (1966). (14) J . A. Montgomery and H. J . Thomas, J . Org. Chem. 2,1411 (1966). (15) H. J . Thomas and J . A . Montgomery, J . Org. Chem. 2, 1413 (1966). (16) R. J. Rousseau, L. B. Townsend and R. K. Robins, Chem. Comm. 265 (1966). (17) B. Shimizu and M . Miyaki, Chem. Ind. 664 (1966). '(18) T . J. Bardos, M. P . Kotick and C. Szantay, T e t r a h e d r o n L e t t e r s 1759 (1966). (19) F. K e l l e r and A. R. T y r r i l l , J. Org. Chem. 3l, 1289 (1966). (20) K. J. Ryan, E . M..Acton, and L. Goodman, J . Org. Chem. 3 l , 1181 (1966). (21) M. P . Mertes, S . E . Saheb and D . M i l l e r , J . Med. Chem. 2, 876 (1966). (22) A. D i p p l e and C . H e i d e l b e r g e r , J . Med. Chem. 2, 715 (1966). (23) F. K e l l e r , N. Sugisaka, A. R. T y r r i l l , L. H. Brown, J. E. Bunker and I . J . B o t v i n i c k , J. Org. Chem. 2, 3842 (1966). (24) R. Duschinsky, T. G a b r i e l , M. Hoffner, J . B e r g e r , E . T i t s w o r t h , E . Grunberg, J. H. Burchenal and J. J. Fox, J. Med. Chem. 2, 566 (1966). (25) E . Walton, F. W. H o l l y , G. E. Boxer, R. F. N u t t , J . Org. Chem. 3l, 1163 (1966). (26) T. Kishikawa and H. Yuki, Chem. Pharm. B u l l . (Tokyo) l4, 1360 (1966). (27) T. Kishikawa, T . Yamazaki and H. Yuki, Chem. Pharm. B u l l . (Tokyo) 14, 1354 (1966). (28) L. M. L e r n e r and P . Kohn, J . Org. Chem. 31, 339 (1966). (29) K. R. D a r n a l l and L. B. Townsend, J . H e t e r o c y c l i c Chem. 3, 371 (1966). (30) W. V. Curran and R. B. AngiFr, J . Org. Chem. 3l, 201 (19z6). (31) M . Bobek, J. Farkag and F. Sorm, T e t r a h e d r o n L e t t e r s 3115 (1966). (32) W . Asbun and S . B. B i n k l e y , J. Org. Chem. 3 l , 2215 (1966). (33) J. P. Horwitz, J. Chua, M . A. DaRooge, M. Noel and I. L. Klundt, J . Org. Chem. 3 l , 205 (1966).
Chap. 29
N u c l e o side s and N u c l e o t i d e s
Scha ef f e r
31 1 -
(34) J. P . H. Verheyden and J . H. M o f f a t t , J . Am. Chem. SOC. 88,5684 (1966). (35) J . R . McCarthy, J r . , M . J . Robins, L. R. Townsend and R . K . Robins, J . Am. Chem. S O C . 88, 1549 (1966). (36) J . P . Horwitz, J . Chua and M . Noel, T e t r a h e d r o n L e t t e r s 1343 (1966). (37) M . J . Robins, J . R . McCarthy, J r . and R. K . Robins, B i o c h e m i s t r y 5, 224 (1966). (38) J . J . Fox, N . C . Miller and R. J . Cushley, T e t r a h e d r o n L e t t e r s 4927 (1966)(39) E . R . G a r r e t t , J . K. S e y d e l and A . J . Sharpen, J . Org. Chem. 2, 2219 (1966). (40) H. P . M . Fromageot and C . B . Reese, T e t r a h e d r o n L e t t e r s 3499 (1966). (41) A . Hampton and A . W. N i c h o l , B i o c h e m i s t r y 5, 2076 (1966). (42) B . E . G r i f f i n , M . Jarman, C . B . Reese, J . E . S u l s t o n and D . R . Trentham, B i o c h e m i s t r y 5, 3638 (1966). (43) 1. F r i c , J . Smejkal and J . F a r k a s , T e t r a h e d r o n L e t t e r s 75 (1966). (44) T. L. V. U l b r i c h t , T . R . Emerson and R. J . Swan, T e t r a h e d r o n L e t t e r s 1561 (1966). (45) R . J . Cushley, K . A . Watnabe and J . J . Fox, Chem. Corn. 598 (1966). (46) H . T. S h i g e u r a , G. E . Boxer, M . L. Meloni and S . D . Sampson, B i o c h e m i s t r y 2, 994 (1966). (47) A . G i n e r - S o r o l l a , S . O'Bryant, J . H. Burchenal and A . Bendick, B i o c h e m i s t r y 5, 3057 (1966). (48) R. K . Robins, L. B. Townsend, F . C a s s i d y , J . F . Gerster, A. F . L e w i s and R . L . M i l l e r , J . H e t e r o c y c l i c Chem. 3, 110 (1966). (49) J . J . Fox and K . A . Watanabe, T e t r a h e d r o n L e t t e r s 897 (1966). (50) C. L . S t e v e n s , T . S . Sulkowski and M. E . Munk, J . Org. Chem. 3l, 4014 (1966). (51) Y . F. S h e a l y and J . D . C l a y t o n , J . Am. Chem. SOC. 88, 3885 (1966). (52) G. B . Chheda and R. H. H a l l , B i o c h e m i s t r y 5 , 2 0 8 2 (1966). (53) R. T . L e t s i n g e r and V. Mahadevan, J . Am. Chem. SOC. 87, 3526 (1965). (54) R . T . L e t s i n g e r and V. Mahadevan, J . Am. Chem. SOC. 88, 5319 (1966). (55) H. Hayatsu and H. J . Khorana, 3. Am. Chem. SOC. 88, 3182 (1966). (56) F . C r a m e r , R. H e l b i g , H. H e t t l e r , K. H. S c h e i t and H . S e l i g e r , Angew. Chern.Intern. Ed. E n g l . 5, 601 (1966). (57) F. C r a m e r , Angew. Chern.Intern. Ed. E n g l . 5, 173 (1966). (58) R . Lohrmann, D . S811, H . Hayatsu, E . Ohtsuka and H. G. Khorana, J . Am. Chem. SOC. 8 8 , 8 1 9 (1966). (59) B . E . G r i f f i n , C. B . R e e s e , G . F . S t e p h e n s o n and D . R . Trentham, T e t r a h e d r o n L e t t e r s , 4349 (1966). (60) A , Hal? and J . Smrt, C o l l e c t i o n Czech. Chem. Comun. 31, 3800 (1966). (61) R. Lohrmann and H . G. Khorana, J . Am. Chem. SOC. 88, 829 (1966). 1061 (62) M . Honjo, Y . Furukawa and K . Kobayashi, Chem. Pharm. B u l l . (1966). (63) M . Honjo, Y . Furukawa and K . Kobayashi, Chem. Pharm. B u l l . (Tokyo) 14, 1061 (1966). (64) T M i z u n y and T . S a s a k i , J . Am. Chem. SOC. 88, 863 (1966). (65) J . Nagyvary, B i o c h e m i s t r y 5, 1316 (1966). (66) M . Honjo, R . Marumoto, K. Kobayashi and Y . Yoshioka, T e t r a h e d r o n L e t t e r s 3851 (1966).
14,
Chap. 30 STEROIDS Raphael Pappo, G. D. Searle & Co., Chicago, Illinois Introduction. Interest in the field of steroids remains undiminished.
A major breakthrough was achieved in the elucidation of the biosynthesis of sterols. Strong evidence has been obtained showing that squalene 2,3-oxide is an intermediate in the conversion of squalene to cholesterol.I 3 2, 3, Other important contributions were in the area of total synthesis. Compounds of type I were converted to the required optically active interusing microbiological transformations. mediates I1 in about 70s yield, 5 j
'
or R =
r-
(I?
Thus it has been possible for the first time to effect an asymmetric total synthesis of steroids. Androstane Series. The selective reduction of steroids by homogeneous catalytic hydrogenation has been studied and shown to be promising.7JB A new angular methylation procedure, at C19, involving the Simmons-Smith reagent was discovered, thus extending the usefulness of the Smith-Torgov total synthesis of 19-nor~teroids.~The preparation and properties of 5,19-cyclosteroids was the subject of several studies.lo,ll Interestingly enough, the Villsmeier reaction on enamines of 3-keto-A4-steroids led to the 4,6-difo-l derivatives.I2 Additional work with ammonium sulfide has shown that it is a usefil reagent for the hydrogenolysis of selenides obtained as by-products in the selenium dioxide dehydrogenation of 3-keto-A4-steroids to the corresponding A1 7 *-ketones.I3
Among new compounds of interest one should mention lWestra-4-en3-ones,14 A-homotest~sterone,~~ and 2-oxa-estra-5-en-3-ones.16 A total synthesis of resolved 17~-hydroyy-des-A-androst-9-en-5-one has been described in connection with the preparation of 1Wmethyl steroids.17,1B Conessine was degraded by an elegant and simple method to
Chap. 30
Steroids
PapPo
313 -
13p-cyano-18-nor-5a-androstane derivatives.lS The photolysis of 3-0x04,5-epoxides led to 3,5-dioxo-10(5-4)abeo steroids.20 Pregnane Series, Steroid ally1 and propargyl enol ethers undergo the Claisen rearrangement.a Surprisingly, cyanogen bromide reacts with 18hydroxy-20-dimethylamino steroids to form the corresponding 18,20-epo~y derivatives.22 Additional work has been reported on the synthesis of 18-methyl steroids.23J 24J 25 Estratriene Series. The Wyeth chemists have published details of their w o r k z " j ~ ~ zon y the total synthesis of estratriene derivatives prepared mainly for biological evaluation. In addition they described also a new The ~ Merck group working along similar lines total synthesis of e q ~ i l i n . ~ has found that IV is easily prepared from I11 and can be used to alkylate 2-aUryl-cycLopentane-1,3-diones in cases where I11 fails. 31 They also AcO-
&+m(:
CH2S-C
CH30
\
CH3O
(1111
published work on the chemistry of dl-8(14)dehydroestrone. 32 The total synthesis of 6-thia,33 4-aza,34 b-am, 35 and 8,13-diazaW steroids has been reported. A l o n g different lines, it was interesting to note the report that l'j$-hydroxyestrone and 15p-hydroxy-l7$-estradiol are present in the urine of pregnant women.38
Corticosteroids. An interesting paper described the use of an iridium catalyst for the stereoselective hydrogenation of a 36-methylene steroid.37 Some interesting theoretical considerations were discussed in connection with the solvolysis of 9cz,ll$-dichloro-steroids. 38 A novel reagent, s u l f u r dioxide and N-bromoacetamide, f o r the dehydration of U p hydroxy-steroids has been di~cwered.~' The total synthesis of a hydrocortisone derivative was described by the Roussel Sterols. A considerable amount of work was devoted to the study of backbone r e a r r a n g e m e n t ~ . * ~ JWhile ~ ~ ~ ~partial ~ syntheses of an insect moulting hormone, ecdysone, were announced by several g r ~ ~ evidence is accumulating on the widespread occurrence in nature of its hydroxylated derivatives. This year saw the isolation of 20-hydroxyecdysonsl from silkworm4' (ecdysterone)," crayfish5* (crustecdysone),52 oak-silk moth, tobacco horn~orm,'~ and from plants such as Podocarpus r~akaii,~~ Podocarpus elat~s,~' and Achyranthi~.~~ The ready isolation of insect-moulting hormones from plants in contrast to the extremely poor
p
314 -
Sect. VI
-
Topics i n Chemistry
S m i s sman, Ed.
yield from insects and other sources makes it possible to obtain for the first time large amounts of active substances for biological experimentation. Nitrilium ion intermediates have been shown to have synthetic utility.56 Addition of phosphate carbanion to 3-keto steroids could be controlled to yield either cis or trans 01efin.'~ Antibiotics. Cephalosporin PI was shown to have structure V with a fusidane framework:58
HO - :
H
CH3
:
OAC
Fusidic acid has been degraded to adrenocortical hormone analogs5' and to derivatives of b,&, 14&trimethyl-18-norandrostane .60j61 "he structure of Withaferin A has been confirmed by degradation to bisnor-5acholanic acid.62 Cardenolides. The synthesis of digitoxigenin was announced,63 while cardenolides of novel structure were described by the Ayerst chemists.64 Reichstein and his group are continuing their work on the structure determination of various natural cardenolides.659 86 Steroidal Alkaloids. Photolysis of (22s:25S)-N-chloro-22,26-Mno-5& cholestan-3B-01 and the corresponding 168-hyhroxy substituted (22s:25R)-, (22S:25S)-, and (22-S:25R)-N-chloro compounds caused fragmentation to a mixture of the corresponding 20R and 20s chloropregnane derivatives. Whereas photolysis of (22R:25S )-N-chloro-22,26 -imino-5c%-cholestan-3~-ol gave the corresponding l6-chloro derivative.67 W-irradiation of the stereoisomeric N-nitroso-22,26-irninocholestane-3j3,16j3-di01~ in acidic solution led to the corresponding spirosolane alkaloids soladulcidine, solasodine, and tomatidine respectively, by way of the intermediate A22(N)
Chap. 30
Steroids
PapPo
315 -
imine.68 Dehydrogenation of Demissidine cinimide gives the corresponding A22(N product.
'
mercuric acetate or N-bromosuc9thimonium salt as the main
The acid catalyzed rearrangement of conessine was reinvestigated recently and the structures of the two reaction products i~oconessine~~ and neoconessinen were elucidated. Isoconessine was proved to be 38dimethyla~ino-5B-methyl-19-norconan-8-enewhereas neoconessine has the (VI) novel structure 3&dimethylmino-abeo-l(lO-5 )5~~-conan-8-ene
.
CH3 I
It is interesting to note that in the case of isoconessine, the double bond migration ends at carbon 8, whereas in the case of the cholesterol derivatives the process continues f'urther causing rearrangement of the angular methyl attached to the 13 po~ition.*~,~~,*~ Steroidal alkaloids from Paravallaris microphylla, containing the 1840 lactone system, have been related to conessine, by the conversion of N-methyl-dihydroparavallaridine to dihydroconessine.72 An unusual hydride transfer was during the Eschweiler-Clarke methylation of compound VII. The products isolated, VIII and M, were derived from an intermediate oxidized at C20.
s OH
CH3
+
N-CH3
316 -
Sect. VI
-
Topics in Chemistry
Smi s sman, Ed.
Alkaloid A isolated from Sarcococca Pruniformi~~~ is a 3a,2Oadiamino-5Gpregnane derivative. Also possessing a pregnane skeleton are the various alkaloids isobted recently from the leaves of Holarrhena Antidy~enterica.~~ In particular, it is interesting to note that kurchiphylline is 2CY-hydroxy-3f3-dimethylamino-5-pregnen-16-one. Samandenone, a new salamander alkaloid was isolated and identified76 as X:
A review on salamander alkaloids has been published.n
Buxenine-G, a cytotoxic alkaloid isolated from Buxus sempervirens, XI, which was established unambiguously by x-ray analysis of Buxenine-G dihydroiodide.78
was shown to possess structure
The structurally related Buxpsiine,7e,80 also isolated from Buxus sempervirens, was pruved to be 313-dimethylamino-4,k l , lbtrimethyl-19-nor-Bhomo-pregna-ga(lo), 9(ll), 16-trien-20-one. Work is continuing on the isolation and identification of new steroidal alkaloids from boxwood species, such as Bwcus balearica,80 Buxus malayana,85. Bwcus rolfei,= Buxus sempervirens,83 and Buxus With few exceptions, these alkaloids have an unusual skeleton koreana.containing a cyclopropane ring and are derived from the 4,4',1b trimethyl-9f3,19-cyclo-5~Lpregnane system.
Chap. 30
Steroids
PapPo
317 -
References 1. 2.
3. 4.
5. 6.
7. 8. 9.
E. J. Corey and W. E. Russey, P. 0. Ortiz de Montellano, J. Am. Chem. Soc., 4750 (196). E. J. Corey and W. E. Russey, J. Am. Chem. Soc., g,4751 (1966). E. E. van Tamelen, J. D. Willett, R. B. Clayton and K. E. Lord, J. Am. Chem. Soc., E, 4752 (lgbb). E. E. van Tamelen, J. Willet, M. Schwartz and R. Nadeau, J. Am. Chem. SOc., 88, 5937 (1966). H. Gibian, K. Kieslich, H.-J. Koch, H. Kosmol, C. Rufer, E. SchrOder, R. Vossing, Tetrahedron Letters, 2321 (1966). P. Bellet, G. Nomine and J. Mathieu, Compt. Rend., 263, 88 (196). C. Djerassi and J. Gutzwiller, J. Am. Chem. Soc., g,4537 (1966). A . J. Birch and K. A. M. Walker, J. Chem. Soc. C, 1894 (lgb6). P. Turnbull, K. Syhora and J. H. Fried, J. Am. Chem. Soc., 88, 4764
g,
(1%6 1. 10. K. Syhora, J. A. Edwards and A. D. Cross, J. Org. Chem., (lgb6). 11. J. Tadanier, J. Org. Chem., 31, 2l24 and 3204 (1966).
2, 3411
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12. R. Sciaky and U. Pallini, Gazz. Chim. Ital., 96, 1241 (lsb). 13. M. Kocor and M. Maczka, Bull. Acad. Polon. Sci., Ser. Sci. Chim.,
14, 347 ( ~ 6 ) .
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.
(1w). C. J. Jung and R. Pappo, U. S. Patent 3,280,149.
Z. G. Hajos, D. R. Fdrrish and E. P. Oliveto, Tetrahedron Letters, 6495 (1%). 18. M. Uskokovic, J. Iacobelli, R. Phillion and T. Williams, J. Am. Chem. SOC., 4538 (1966). 19 M.-M. Janot, P. Milliet, X. Lusinchi and R. Goutarel, Compt. Rend., 263, 785 (1966). 20. H. Wehrli, C. Lehmann, P. Keller, J. J. Bonet, K. Schaffner and 0. Jeger, Helv. Chem. Acta, 49, 2218 (1966). 21. R. Vitali and R. Gardi, Gazz. Chim. Ital., 96, U 2 5 (1966). 22. V. :ern$, A. Kasal and F. Sorm, Coll. Czech. Chem. Comm., s, 1752
17*
s,
(1966). V 23. A. Kasal and V. Cernf, Coll. Chem. Comm.,
31, 2759 (1966).
Sect. VI
318
24.
-
Topics in Chemistry
Smi s sman, Ed.
G. V. Baddeley, H. Carpio and J. A. Edwards, J. Org. Chem.,
11, 1020
(1966).
g,
947 (1966).
25
G. A. Hughes, T. Y. Jen and H. Smith, Steroids,
26.
D. P. Strike, T. Y. Jen, G. A. Hughes, G. H. Douglas and H. Smith, Steroids, 8, 309 (1966).
27.
G. A. Hughes and H. Smith, Steroids,
28.
G. H. Douglas, G, C. Buzby, Jr., C. R. Walk and H. Smith, Tetrahedron, 22, 1019 (1966).
29
G. C. Buzby, Jr., C. R. Walk and H. Smith, J. Med. Chem., 9, 783
30.
R. P. Stein, G. C. Buzby, Jr. and H. Smith, Tetrahedron Letters,
31.
C. H. Kuo, D. Taub and N. L. Wendler, Chem. and Ind.,
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L. Re, D. B. R. Johnston, D. Taub and T. B. Windholz, Steroids, 365 ( 1 9 6 ) .
33.
J. G. Westra, W. N. Speckamp, U. K. Pandit and H. 0. Huisman, Tetrahedron Letters, 2781 (igb6).
-8,
547 (1%).
-
(1966). 5015 (1966).
34
-
1340 (1966).
g,
M. A. Sluyter, U. K. Pandit, W. N. Speckamp and H. 0. Huisman, Tetrahedron Letters, 87 (1966)
.
35 * J. H. Burckhalter and H. N. Abramson, Chem. Commun., 895 (1966). 36. R. Knuppen, 0. Haupt and H. Breuer, Steroids, g, 403 (1966). 37. G. I. Gregory, J. S. H u n t , P. J. May, Mrs. F. A. Nice and G. H. P h i l l i p s , J. Chem. SOC. C, 2201
(1966).
38. N. M u r r i l l , R. Grocela, W. Gebert, 0. Gnoj and H. L. Herzog, Steroids, 8, 233 (1%); 39. T. Horawina, D. Ksierny, J. Vaedtke, M. Iwaszkiewicz and W. Lewenstein, Przemysl chem., 45, 437 (1966). 40. R. Bucourt and G. Nomine, B u l l . SOC. Chim. France, 1537 (1966). 41. J. W. Blunt, M. P. Hartshorn and D. N. Kirk,. Tetrahedron, 11, 3195 (1966). 42.
J. W. Blunt, M. P. Hartshorn and D. N. Kirk, Tetrahedron Letters, 2125 (1966).
43.
M. P. Hartshorn and D. N. Kirk, Tetrahedron Letters,
44.
J. B. Siddall, A. D. Cross and J. H. Fried, J. Am. Chem. SOC., 262 (1966).
45.
I. T. Harrison, J. B. S i d d a l l and J. H. Fried, Tetrahedron Letters, 3457 (1966).
3913 (1966).
88,
46. U. Kerb, P. Hocks and R. Wiechert, Tetrahedron Letters, 1391 (1966).
Chap. 30
Steroids
PapPo
319 -
47.
A. Furlenmeier, A . FUrst, A. Langemann, G. Waldvogel, P. Hocks, U. Kerb and R. Wiechert, Experientia, 21, 573 (1%6).
48.
U. Kerb, G. Schulz, P. Hocks, R. Wiechert, A. F’urlenmeier, A. Furst, A. Langemann and G. Waldvogel, Helv. Chim. Acta, 49, lbOl (1966).
49
-
50.
51.
-
P. Hocks and R. Wiechert, Tetrahedron Letters, 2989
(1966).
H. Hoffmeister and H. F. GrEtzmacher, Tetrahedron Letters, 4017 (19Ob 1. F. Hampshire and D. H. S. Horn, Chem. C ~ I ~ I I I . , 37 (1966).
52.
D. H. S. Horn, F. J. Middleton and J. A. Wunderlich, Chem. Comm., 339 (lgbb).
53.
J. N. Kaplanis, M. J. !R~ompson,R. T. Yamamoto, W. E. Robbins and S. J. Louloudes, Steroids, 605 (1966).
5,
K. Nakanishi, M. Koreeda, S. Sasaki, M. L. Chang and H. Y. Hsu, Chem. Comm., 915 (1906).
55.
M. N. Galbraith and D. H. S. Horn, Chem. Comm.,
56.
A. Hassner, L. A. Levy and R. Gault, Tetrahedron L e t t e r s , 3119 (1%6).
57. 58.
H. Kaneko and M. Okasaki, Tetrahedron Letters, 219 (1966).
905 (1966).
T. G. Halsall, E. R. H. Jones, G. Lme and C. E. Newall, Chem. Comm.,
085 (1966). 59.
W. 0. Godtfredsen, W. V. Daehne and J. Vangedal, Chem. Comm., 638 (1966).
60.
P. A. Diassi, G. W. Krakower, I. Bacso and H. A. Van Dine, Tetrahedron, 22, 3443 (1966).
bl.
P. A. Diassi, I. Bacso, G. W. Krakower and H. A. Van Dine, Tetra22, 3459 (1966). hedron, -
b2.
D. Lavie, S. Greenfield and E. Glotter, J. Chem. Soc., 1753 (1960).
63. 64.
N. Danieli, Y. Mazur and F. Sondheimer, Tetrahedron, 22, 3189 (1966).
65.
R. Brandt, W. Stoeklin and T. Reichstein, Helv. Chim. Acta, 49, 1662
66.
R. Brandt, H. Kaufhann and T. Reichstein, Helv. Chim. Acta, 49, 1844 (1966 1. G. Adam and K. Shreiber, Tetrahedron, 22, 3581 (1966).
b7.
68.
69. 70.
-
-
J. M. Ferland, Y. Lefebvre, R. Deghenghi and K. Wiesner, Tetrahedron Letters, 3617 (1966).
1.
-
22,
3591 (1966). K. Shreiber and C. Horstmann, Chem. Ber., 99, 3183 ( 1 9 6 ) . G. Adam and K. Shreiber, Tetrahedron,
P. Devissagnet, M. Pays, F. X. Jarreau, Q. Khuong-Huu and R. Goutarel, Tetrahedron Letters, 1073 (1966).
3 20 -
Sect. VI
-
Topics i n C h e m i s t r y
S m i s s m a n , Ed.
M.-M. Janot, P. Devissagnet, M. Pays, F. X. Jarreau, Q. Khuong-Huu and R. Goutarel, Tetrahedron Letters, 4375 (lgb6). 72 H. P. Husson, R. Beugelmans, P. Potier and J. Le Men, Bull. SOC. Chim. France, 2516 (1%). 73. H. P. Husson, P. Potier and J. Le Men, Bull. SOC. Chim. France, 948
71
(1966).
74 75
X. S. Mukherjee, Chem. and Ind., 769 (196). Me-M. Janot, P. Longevialle and R. Goutarel, Bull. SOC. Chim. France, A. Chatterjee and
1212 (lgdb).
76. G. Habermehl, Chem. Ber., 99, 1439 (1966). 53, 123 (19661. 77. G. Habermehl, Naturwissenschaften, 78. R. T. Puckett, G. A. Sim, E. Abushanab and S. M. Kupchan, Tetrahedron Letters, 3815 (196). 79 J. Tomko, 0. Bauerava, Z. Voticky, R. Goutarel and P. Longevialle, Tetrahedron Letters, 915 (1966). 80.
F. Khuong-Huu, D. Herlem-Gautier, M. M. Qui Khuong-Huu, E. Stanislas and R. Goutarel, Tetrahedron, 22, 3321 (1966). 81. F. Khuong-Huu-Lain&, M.-J. Magdeleine, N. G. Bisset and R. Goutarel, Bull. SOC. Chim. France, 781 (1w). 82. F. Khuong-Huu-Lain6, A. Milliet, N. G. Bisset and R. Goutarel, Bull. SOC. Chitn. France, L216 (1966). 83. S. M. Kupchan and G. Ohta, J. Org. Chem., 2,608 (196b). 84. T. Nakano, S. Terao, Y. Saeki and K. D. Jin, J. Chem. SOC. C, 1805 (1966)
Chapter 31. Reactions of Interest in Medicinal Chemistry Edward E. Smissman, University of Kansas, Lawrence, Kansas An ever increasing number of new and/or novel reactions makes an interesting chore of selecting reactions for this chapter. This report will cover only a small number of the unique reactions reported during 1966 but will attempt to select representative examples of high utility to the medicinal chemist. Reports of excellent results utilizing soluble catalysts continue to support the superiority in selective reductions of systems containing multiple double bonds. Tris (triphenylphosphine) rhodium chloride as a soluble catalyst for hydrogenation allows the reduction of w-nitrostyrene to phenylnitroethane and cinnamylchloride, in part, to phenylpropyl chloride. Deuterium is added to a double bond without the introduction of additional labeling.lI2 Aluminum hydride has given superior results in the reduction of amides, nitriles, oximes, isocyanates, and Schiff bases to the corresponding amines! A comparison of its reducing characteristics with those of lithium aluminum hydride has also been reported.4 The eneamine of cyclooctanone is reduced to cyclooctane in 85% yield with aluminum h ~ d r i d e . ~ Hydrogenation of a,@-unsaturated aldehydes on Raney zinc catalysts was studied. Saturated aldehydes were obtained along with saturated alcohols. The amounts of each were dependent on reaction conditions. On reduction of nitriles and oximes with Raney alloy improved yields of primary amines were obtained.7 Treatment of ketoximes with Raney-nickel yields the ketones. The reduction of nitrobenzene with cyclohexane, cyclohexene, and n-hexane over a series of catalysts on aluminum An oxide afforded aniline in yields greater than g o % . ’ iridium catalyst prepared by Adams’ method is useful for the reduction of nitroaromatics to hydroxylamines.9 Although a,B unsaturated acids are not usually reduced by aqueous sodium borohydride, they a r e in the presence of cyanocobalt complexes to yield the saturated acid.” Various cyanostilbenes were reduced to the corresponding diphenyl cyanoethanes with sodium borohydride in tetrahydrofuran; yields ranged from 72-98%.” A tetrahydrofuran solution of diborane reduced oximes to the corresponding alkylhydroxylamines.’2 A discussion of the stereoselectivity in the reduction of ketones by3metal hydrides gives an excellent route to axial alcohols.
Sect. VI
322 -
- Topics i n C h e m i s t r y
S m i s s m a n , Ed.
Hueckel and co-workers indicate three methods by which reductions in liquid ammonia (Birch reduction) can be performed. They show that the reduction is substantially affected by the sequence in which reagents are added.14 Mechanisms of dimethylsulfoxide oxidations have been studied and an explanation is now available for the fact that the oxidation ro eeds in a weak acid medium and is sensitive A new reagent for the oxidation of alcohols to pH change. lPa" to ketones in neutral solution at room temperature is 4-pheny> 1,2,4-triazoline-3,5-dione. Dry benzene is a convenient solvent, from which the phenylurazole separates during the reaction.16 Cyclic acetals can be oxidized to bromine containing esters under mild conditions using N-bromosuccinimide~7 Palladium acetate gives mainly enol acetates with terminal RCH 2 CH/
'1
8
RCH 2' OCH 2 CH 2Br
' 0
olefins and mainly allylic acetates with 2-01efins.l~ Cobalt (I1 and 111) acetates and sterates catalyze the allylic oxidation of cyclohexene by oxygen at 60' in acetic acid. Molecular oxygen can also be utilized for the direct epoxidation of olefins in acetone solution2' The reaction of propene and other olefins with mercuric salts of some strong oxy acids was shown to give acrolein and analogous carbonyl compounds. This reaction proceeds through a 1:l adduct which in a ueous solution is probably of the Inclusion compounds of diperoxyform CH3CH (OH)CH2Hg+x-. carboxylic anhydrides with urea have been prepared as peroxyacid precursors.22 The inclusion compounds are not shock or heat sensitive. Various unique replacement reactions in aromatic systems have been reported. A one step replacement of aromatic amino groups by chlorine or bromine involves treatment with CuC12NO or CuBrp-NO complexes. The complex is formed in -situ.23 Nitric oxide acts as a diazotization agent and can be used to give higher yields than obtained by other methods.24 Another method of aromatic chlorination involves desulfonylation of aromatic sulfonyl chlorides utiliziiig tris(tripheny1phosphine) rhodium chloride[(Ph3P) 3RhC111' Arylsulfonyl azides give direct amination of benzene when the latter is treated with the azide in the presence of H 2 S 0 ~ . 2 6 Hydroxyl groups can be replaced by methyl at primary carbon atoms via the sodium salt of dimethyl sulfoxide utilizing the following sequence:27 RCH2SOMe + Ni/H -> RMe ROTS + NaCHpSOMe + Me2S0 -> The hydrogenator previously described, which generates hydrogen automatically from NaBH4 has been adapted to hydrochlorination of reactive alcohols and olefins. The apparatus allows quantitative conversion into product without excessive contact with hydrochlorination agent.28 Phosphorous
"
Chap. 31
Chemical Reactions
Smi s sman
323 -
acid with iodine and alcohols affords alkyl iodides in 75-96% yield." In polar inert solvents, CuC12 can convert acid chlorides, anhydrides, and carboxylic anhydrides into a-chloro derivatives with selectivities greater than 95%. This method can be used to prepare pure a-monochloro acids re ardless of the number of a-hydrogen atoms in the substrate. 3 % A simple method for the preparation of primary amines from aliphatic halides involves the treatment of the halide with KOCN in alcohol to give the urethane which is hydrolyzed to the amine. In general the yields are high.31 A novel conversion in which tetrakis(dimethylamin0) titanium converts carboxylic acids and their common derivatives in orthoamides and ketene N,N-acetals in good yields is described. 3 2 a r b Quinoline 1-oxide can be substituted by mercaptans with the 3-isomer being the major product.33 Heterocyclic acid amides, such as 10-methyl-9-acridone and 2-methyl-1-phthalazone, were aminoalkylated by ClMg(CH2) 3NMe3. The carbinols formed have the character of pseudo bases and were transformed to the corresponding acridinium or phthalazinium salts. 3 4 A useful synthesis of a wide variety of ketones was developed by mono- and dialkylation of 6-oxosulfoxides. Reductive cleavage of these alkylated products with aluminum amalgam produces the desired ketone35 Hauser and co-workers continue to investigate the alkylation of dianions.36 A study was made of the relative reactivities of disodio salts of 6-diketones toward alkyl halides in liquid NH3. The order of relative reactivities observed was isobutyryl, propionyl> acetyl > phenylacetyl. Sodium a-sodioacetate reacts with aliphatic dihalo compounds and aromatic hydrocarbons containing side chain halo groups to give the di- and monocarboxylic acids, respectively.37 0-alkylation of ketones to produce enol ethers utilizing triethyloxonium fluoroborate or a dialkyl sulfate occurs readily in dimethylformamide and dimethyl sulfoxide.38 1,3-Dipolar addition to unsaturated compounds affords routes to unique and interesting structures. The 1,3-dipolar cycloaddition of the 0-methyl ether of dinitromethane to methyl acylate produced N-methoxy-3-nitro-5-carbomethoxyisoxazolidine in 65% yield. Similar results were obtained with other olefins.39 Acetonitrile N-oxide adds to enynes to form isoxazolines and isoxazoles.40 Additions to multiple bonds catalyzed by radical initiators produce novel synthetic methods,Carboxylic acids add to acetylenic compounds in the presence of organic peroxides. Acetic acid and acetylene yield adi ic acid; 1-hexyne and acetic acid give octen-3-oic acid. Radical amination of olefins with hydroxylamine sulfonic acid and hydroxylamine in the presence of FeC12 gives the corresponding l-amino-2chloro compounds.42
"
324 -
Sect. VI
-
Topics in C h e m i s t r y
Smi ssman, Ed.
The steric course of additions of amines and alcohols to acetylene dicarboxylic ester was studied under various conditions.43 Secondary amines gave stereospecifically cis addition product. Nitrosyl formate can be generated situ in the presence of an olefin to yield the nitrosoformate h on hydrolysis affords the hydroxynitroso compound in high yield.44 Transoximination gave the a-hydroxy ketone. Phosphorous tribromide can be added to olefins to yield 1:l adducts with uv irradiation, peroxides, or heat as initiator^!^ Similar results are obtained with PC13. Maleic anhydride condenses with G ; k r 2 olefins in an ene synthesis to give substituted succinic anhydrides. An review of the preparative use of the Diels-Alder reaction relating predominantly to recent results gives a systematic approach to this useful reaction. 4 7 The direct brominative cyclization of methyl farnesate was accomplished utilizing N-bromosuccinimide in aqueous MeOCH2CH20Me.48 Bor~ntrichloride~'and boron tribromide5' have been studied further as dealkylating agents with regard for specificity and neighboring group effects. Mercuric salts of carboxylic acids decompose in uv light or in the presence of peroxides to form alkylmercury derivatives.51 Aqueous peroxydisulfate can be used to decarboxylate N-acetylamino acids to give aldehydes or ketones, acetamide, and Con. 5 2 Dehydrogenation of amine derivatives with Hg-EDTA can give rise to hydroxy lactams by the following sequence:53
RL?
>-
rB]
d
"3
PhCH(OH)CH2N
A reagent for dehydrohalogenations is 1,5-diazabicycl0(4.3.0)5-nonene has been shown to be versatile and capable of being used under mild conditions.54 The reaction of &-dibromides with thiourea gave olefins in high yields.55 The ylides, alkylidenetriphenylphosphoranes, tend in general towards cis olefin formation. The proportion of cis olefin is highest when ylide is salt-free while lithium salts favor trans isomers.56 Ylides can be prepared by the treatment of
Q U
Chap. 3 1
Chemical Reactions
Smis sman
325 -
phosphines R’R2PCH2R3(R1=Ph;R2=Ph, CH2Ph; R3=Ph, COpEt) with activated olefins H2C=CHR4(R4=CN, CONHp, C02Et). These ylides can be used in situ in Wittig olefin syntheses under mild conditions, with or without a hydroxylic solvent.57 The synthesis of stable sulfonium ylides is described.” Trichloroacetic acid reacts with cyclic enamines to give the chloromethyl derivatives. This demonstrates that trichloromethyl anion will react preferentially with an organic a r 1 3 cationic species rather than undergo loss of chloride ion cc13 to give dichlorocarbene.” Oxidation of benzyl ketone hydrazones with Hg2 (O2CCF3) in ether or dioxane gives a direct synthesis of phenylacetyl6 o Olefin formation occurs with saturated enes (C~HSCECR). aldehydes and carboxylic acids when they are allowed to react with ruthenium and rhodium complexes.61 Olefins can be converted to aldehydes in high yields by ozonization followed by treatment with dimethylsulfide.62 Dimethylsulfoxide was found to increase the rate of hydrolysis in esters which were resistant to saponification.63 Treatment of alkyl toluenesulfonates with sodium naphthalene anion radical in tetrahydrofuran constituted an almost ideal procedure €or regenerating the corresponding alcohols.64 The hydration of nitriles to amides in the presence of nickel catalysts shows an increase in yield with the addition of pyridine.65 A convenient synthesis of tert-alkyl amines involves the amination of the methine group with trichloroamine-aluminum chloride.66 Organoboranes from both hindered and unhindered
3
BN3
R3CH
+ NC13 + AlCl3
> -
R3CNH2
olefins can be converted to the corresponding amines by treatment with H z N O S O ~ H . Isocyanates ~~ and isothiocyanates give 2oxazolinyl-2-amines and 2-thiazolinyl-2-amines when treated with aziridinium tetrafluorobrate.68 A continuing investigation of amino ketone rearrangeR-N RN H ments has produced a novel H N N route to a variety of 2-alkylamino-2-phenylcyclohexanones and 2-alkylamino-2-phenylcyclohex ano1s.69’70 2-Alkyl-A‘-piperidienes were obtained in good purity from the corresponding 1-alkylcyclopentanols with NaN3 and HzSOL,. 7 1 Primary, secondary, and tertiary amines were produced by the reaction of nitro compounds with aliphatic alcohols in the presence of aluminum oxide.72 The formation of various amides from aliphatic and aromatic carboxylic acid hydrazides in the Tresence of chloral involves a novel dehydrazination reaction.7 Reductive
7rS]
-If0]
Sect. VI - Topics in C h e m i s t r y
326 -
RCONHN:CHCC13
+
R'NH;! ->
[?
Smi s sman, Ed.
1
l!
R-C-NHN:CHCC13 --> R NHR' NHR ' elimination of diazo nitrogen via the sequence Y:N:N --> YH2 + N2 (Y=RCON:, RCOC:) can be extended to include reductive desamination of primary amines through the diazonium salt.74 Benzazide on photolysis in isopropyl alcohol gave quantitative yields of benzamide and acetone. Hydrazines can be acetylated in the presence of dicyclohexylcarbodiimide to give monoacetyl (on the more basic nitrogen) and diacetylhydrazines in good yields.76 Glycidic nitriles can be pre ared from chloroaldehydes by treatment with sodium ~yanide.'~ RR'CClCHO + NaCN -> Refluxing 1-nitro-2-alkanols in HC1 gave high yields the CN corresponding a-hydroxy acids.78 R' Ketol nitrates (e.g. E-BrC ~ H ~ C O C H ~ O N Oare Z ) readily converted in good yields to the corresponding dicarbonyl derivatives (e.g. E - B ~ C ~ H ~ C O C H O under the influence of sodium acetate in CH3SOCH3.79 The a-bromo ketones are treated with silver nitrate to give the nitrate which is used without isolation. The efficiency of drying agents of organic solvents was examined using near IR techniques. The agents CaC12, CaSO4, MgS04, mol. sieves-type 4a, and Na2SO4 were determined for the removal of H20 in solution from C6H6, Et20, and EtOAc. CaC12, CaS04, and mol. sieves were fast drying; MgS04 and Na2S04 were slow drying agents and removed only small amounts Of H20." In small amounts methyl sulfinyl carbanion is prepared safely. When 4.5 moles of sodium hydride was added in 5 portions to 18.4 moles of dimethylsulfoxide at 70' and stirred the temperature rose sharply and an explosion occurred.*'
'fl-
Chap. 31
(1)
Chemical Reactions
3 27 -
Smi s sman
A. J. Birch and K. A. M. Walker, J. Chem.
SOC.,
C, Org.
1894 (1966). J. F. Biellmann and H. Liesenfelt, Compt. Rend., 2 6 3 , (2) 251 (1966). (3) M. Ferles, Z. Chem. 6 , 2 2 4 ( 1 9 6 6 ) . (4) H. C. Brown and N. MT Yoon, J. Am. Chem. SOC. 88, 1 4 6 4 (1966). J. M. Coulter and J. W. Lewis, Tetrahedron Letters 3 7 1 5 (5) (1966). (6) E. J. Mistrik, J. Nevydal, and V. Macho, Chem. Zvesti 20 641 (1966). B. Staskun and T. van Es, J. Chem. SOC., C, O r g . 5 3 1 (7) (1966). (8) N. S. Kozlov and N. K. Marveeva, Uch. Zap. Permsk. Gos. Ped. Inst. 32, 1 4 ( 1 9 6 5 ) . (9) K. T a G , Chem. Commun. 4 6 4 ( 1 9 6 6 ) .
( 1 0 ) A. Kasahava and T. Hongu, Yamagata Daigaku Kiyo, Shizen Kagaku 6 , 2 6 3 ( 1 9 6 5 ) . (11) J , Knabe, R. Herbort, and N. Ruppenthal, Arch. Pharm. 299, 534 ( 1 9 6 6 ) . (12) A. A. Medvedeva and S. S. Novikov, Izv. Akad. Nauk SSSR 1537 (1966). (13) D. C. Ayres and R. Sawdaye, Chem. Commun. 5 2 7 ( 1 9 6 6 ) . (14) W. Hueckel, S. Gupte, and M. Wartini, Chem. Ber. 99, 1388 (1966). (15) a) K. Torssell, Tetrahedron Letters 4 4 4 5 ( 1 9 6 6 ) b) A. H. Fenselau and J. G . Moffatt, J. Am. Chem. SOC. 88, 1 7 6 2 ( 1 9 6 6 ) . (16) R. C. Cookson, I. D. R. Stevens, and C. T. Watts, Chem. Commun. 7 4 4 ( 1 9 6 6 ) .
(17) J. D. Prugh and W. C. McCarthy, Tetrahedron Letters 1351 (1966).
(18) W. Kitching, Z. Rappoport, S. Winstein, and W. G. Young, J. Am. Chem. SOC. 8 8 , 2 0 5 4 ( 1 9 6 6 ) . (19) M. Prevost-Gzgneux, Rev. Inst. Franc. Petrole Ann. Combust Liquides 21, 9 1 1 ( 1 9 6 6 ) . S. L. Reid and D. B. Sharp, U. S. Pat. 3,228,967. (20) (21) B. C. Fielding and H. L. Roberts, J. Chem. SOC., A, 1627 (1966). (22) L. Heslinga and W. Schwaiger, Rec. Trav. Chim. 85, 7 5 (1966). (23) W. Brackman and P. J. Smit, Rec. Trav. Chim. Pays-Bas 85. 857 ( 1 9 6 6 ) . J. 'Rigaudy and J. C. Vernieres, Compt. Rend. 261, 5516 (24) (1965). (25) J. Blum, Tetrahedron Letters 3 0 4 1 ( 1 9 6 6 ) . G. S. Sidhu, G. Thyagarajan, and U. T. Bhalerao, Chem. (26) Ind. 1301 ( 1 9 6 6 ) . (27) T. J. Broxton, Y. C. Mac, A. J. Parker, and M. Ruane, 1 9 , 521 ( 1 9 6 6 ) . Australian J. Chem. -
3 28 -
Sect. VI
- Topics in C h e m i s t r y
Smi s sman, Ed.
( 2 8 ) H. C. Brown and M. H. Rei, J. Org. Chem., 3 1 , 1 0 9 0 ( 1 9 6 6 ) ( 2 9 ) N. G. Feshchenko and A. V. Kirsanov, Zh. Obshch. Khim. 36, 157 (1966). ( 3 0 ) R. Louw, Chem. Commun. 5 4 4 ( 1 9 6 6 ) ( 3 1 ) A. Nagasawa, H. Kitano, and K. Fukui, Nippon Kagaku Zasshi 8 7 , 4 8 5 ( 1 9 6 6 ) . Weingarten and W. A. White, J. Am. Chem. SOC. 88, ( 3 2 ).H)a 8 5 0 ( 1 9 6 6 ) ; b) J . Org. Chem. 31, 2 8 7 4 ( 1 9 6 6 ) . ( 3 3 ) L. Bauer and T. E. Dickerhofe, J. Org. Chem. 3 1 , 9 3 9 (1966). ( 3 4 ) A. Marxer, Helv. Chim. Acta 4 9 , 5 7 2 ( 1 9 6 6 ) . ( 3 5 ) P. G. Gassman and G. D. R i c G n d , J. Org. Chem. 31, 2355 1 9 6 6 ) . ( 3 6 ) K. G. Hampton, T. M. Harris, and C. R. Hauser, J. Org. 31, 6 3 3 ( 1 9 6 6 ) . Chem. 3 1 , 1 0 3 5 ( 1 9 6 6 ) ; J . Org. Chem. ( 3 7 ) H. Hopff and H. Diethelm, Ann. Chem. 6 9 1 , 6 1 ( 1 9 6 6 ) . ( 3 8 ) G. J . Heiszwolf and H. Kloosterziel, Chem. Commun. 2 (1966). ( 3 9 ) V. A. Tartakovskii, I. E. Chlenov, N. S . Morozova, and S. S. Novikov, Izv. Akad. Nauk SSSR 3 7 0 ( 1 9 6 6 ) . ( 4 0 ) L . K. Vagina, V. N. Chistokletov, and A. A. Petrov, Zh. Organ. Khim. 2 , 4 1 7 ( 1 9 6 6 ) . 44, 2241 ( 4 1 ) J. DiPietro and W. J. Roberts, Can. J. Chem. (1966). 48, 132 ( 4 2 ) F. Minisci, R. Galli, and M. Cecere, Chim. Ind. (1966). ( 4 3 ) E. Winterfeldt and H. Preuss, Chem. Ber. 9 9 , 4 5 0 ( 1 9 6 6 ) . ( 4 4 ) H. C. Hamann and D. Swern, Tetrahedron Letters 3 3 0 3 (1966). ( 4 5 ) B . Fontal and H. Goldwhite, J. Org. Chem. 3 1 , 3 8 0 4 ( 1 9 6 6 ) ( 4 6 ) C. Agrami, M. Andrac-Taussig, C. Justin, and C. Prevost, Bull. SOC. Chim. France 1 1 9 5 ( 1 9 6 6 ) . ( 4 7 ) J . Sauer, Angew. Chem. Inter. Ed. 5 , 2 1 1 ( 1 9 6 6 ) . ( 4 8 ) E. E. Van Tamelen and E. J. Hessler, Chem. Commun. 4 1 1 (1966). ( 4 9 ) F. M. Dean, J. Goodchild, L. E. Houghton, J. A. Martin,
-
-
-
R. B. Morton, B. Parton, A. W. Price, and N. Somvichien, Tetrahedron Letters 4 1 5 3 ( 1 9 6 6 ) . ( 5 0 ) V. Stehle, M. Brini, and A . Pousse, Bull. SOC. Chim. France 1100 ( 1 9 6 6 ) . (51) Y . A. Ol'dekop and N. A. Maier, Izv. Akad. Nauk SSSR, Ser. Khim. 1 1 7 1 ( 1 9 6 6 ) . ( 5 2 ) H. L. Needles and R. E. Whifield, Chem. Ind. 2 8 7 ( 1 9 6 6 ) . ( 5 3 ) H. Moehrle, Arch. Pharm. 2 9 9 , 1 8 ( 1 9 6 6 ) ; Angew. Chem. Intern. Ed. 5 , 2 5 7 ( 1 9 6 6 ) . ( 5 4 ) H . Oedyger, Chem. Bey. 9 9 , 2 0 1 2 ( 1 9 6 6 ) . ( 5 5 ) K. M. Ibne-Rasa, N. M u h G a d , and Hasibullah, Chem. Ind. 1 4 1 8 ( 1 9 6 6 ) . ( 5 6 ) M. Schlosser, G. Mueller, and K. F. Christmann, Angew. 5, 667 ( 1 9 6 6 ) . Chem. Intern. Ed. -
Chap. 31 (57) S. (58) A. (59) G. (1966) 9 R. (60) R. (61) J. (62)
Chemical Reactions
Smissman
329 -
Trippett, Chem. Commun. 4 6 8 ( 1 9 6 6 ) . Hochrainer and F. Wessely, Monatsh. Chem. 9 7 , 1 (1966) H. Alf and A. J. Speziale, J. Org. Chem. 31,1340
J. Theis and R. E. Dessy, J. Org. Chem. 31, 6 1 2 (1966) H. Prince and K. A. Raspin, Chem. Commun,l56 (1966). J. Pappas, W. P. Keaveney, E. Gancher, and M. Berger, Tetrahedron Letters 4 2 9 3 ( 1 9 6 6 ) J. Sfiras and A. Demeilliers, Recherches (Paris) 15, 83 (63) (1966) (64) W. 88, 1 5 8 1 (65) K. (1966). (66) P.
D. Closson, P. Wriede, and
S.
Bank, J. Am. Chem. SOC.
(1966).
Watanabe and K. Sakai, Bull. Chem. SOC. Japan 39, 8
Kovacic, R. J. Hopper, S . S. Chaudhary, J. A. Levisky, and V. A. Liepkalns, Chem. Commun. 2 3 2 ( 1 9 6 6 ) . (67) M. W. Rathke, N. Inoue, K. R. Varma, and H. C. Brown, J. Am. Chem. SOC., 88, 2 8 7 0 ( 1 9 6 6 ) . (68) E. Pfeil and K. Milzner, Angew. Chem., Intern. Ed. 5, 667 ( 1 9 6 6 ) . (69) C. L. Stevens, A. B. Ash, A. Thuillier, J. H. Amin, A.
Balys, W. E. Dennis, J. P. Dickerson, R. P. Glinski, H. T. Hanson, M. D. Pillai and J. W. Stoddard, J. Org. Chem. 31, 2593 (70)
(1966).
C. L. Stevens, A. Thuillier, K. Grant Taylor, F. A. Daniher, J. P. Dickerson, H. T. Hanson, N. A. Nielsen, N. A. 31, 2 6 0 1 ( 1 9 6 6 ) . Tikotkar, and R. M. Weier, J. Org. Chem. (71) K. Dietzsch, Z. Chem. 6, 9 8 ( 1 9 6 6 ) . (72) N. S. Kozlov and V. Sh, Pasternak, Zh. Organ. Khim. 2 , 461 (1966). (73) T. Kametani and 0. Umezawa, Chem. Pharm. Bull. 14, 369 (1966). L. Horner and G. Bauer, Tetrahedron Letters 3 5 7 3 ( 1 9 6 6 ) . (74) (75) A. Buzas, C. Egnell, P. Freon, and F. Canac, Compt. 262, 845 ( 1 9 6 6 ) . Rend., Ser. C (76) A. Buzas, F. Canac, C. Egnell, and P. Freon, Compt. Rend., Ser. C. 2 6 2 , 6 5 8 ( 1 9 6 6 ) . (77) J. Cantacuzene and D. Ricard, Tetrahedron Letters 2 2 3 7 (1966). (78) V. V. Perekalin, A. K. Petryaeva, M. M. Zobacheva, and 166, 1129 ( 1 9 6 6 ) . E. L. Metelkina, Dokl. Akad. Nauk SSSR (79) N. Kornblum and H. W. Frazier, J. Am. Chem. SOC. 88, 865 ( 1 9 6 6 ) . (80) B. D. Pearson and J. E. Ollerenshaw, Chem. Ind. 3 7 0 (1966). (81) F. A. Frech, Chem. Eng. News 44, 48 ( 1 9 6 6 ) .
-
3 30 -
Chapter 3 2 .
A n t i r a d i a t i o n Agents
W i l l i a m 0. Foye, Massachusetts College of Pharmacy, Boston
Advancement i n knowledge of s t r u c t u r a l requirements f o r chemical p r o t e c t i o n a g a i n s t i o n i z i n g r a d i a t i o n has continued mainly through m o d i f i c a t i o n of s t r u c t u r e s having known prot e c t i v e e f f e c t s . Knowledge of t h e e f f e c t s of i o n i z i n g radiat i o n on b i o l o g i c a l systems, p a r t i c u l a r l y i n regard t o enzymes, p r o t e i n s , and n u c l e i c a c i d s , has undergone a marked expansion, and new approaches t o improved r a d i o p r o t e c t i v e a g e n t s should be forthcoming. Since t h i s d i s c u s s i o n i s concerned p r i m a r i l y w i t h t h e development of new p r o t e c t i v e agents f o r mammalian c e l l s , mention here can be made only t o s e v e r a l r e c e n t reviews concerned w i t h r a d i o b i o l o g i c a l e f f e c t s of i n t e r e s t t o t h e medicinal chemist. These include t h e r a d i a t i o n chemistry of p r o t e i n s and enzymes: e l e c t r o n s p i n resonance and t h e e f f e c t s of r a d i a t i o n on b i o l o g i c a l systems: and t h e chemical, physical, and b i o l o g i c a l a s p e c t s of energy t r a n s f e r i n r a d i a t i o n proce s s e s ? Chapters on ESR s t u d i e s , r a d i c a l scavengers, and s e r o t o n i n i n regard t o r a d i o p r o t e c t i o n * have been w r i t t e n as w e l l as one on t h e r e a c t i o n s of t h e hydrated e l e c t r o n w i t h b i o l o g i c a l substances of importance? Reviews - A handbook of r a d i o p r o t e c t i v e agents has appeared i n Russian: and a c h a p t e r on chemical a g e n t s t h a t i n f l u e n c e t h e e f f e c t s of r a d i a t i o n i n mammals i s now included i n "Progress i n Drug Research"? Radioprotection of mammals by t h i o l i c compounds' and a m i n o t h i o l s s y l o has been reviewed, as w e l l as t h e more g e n e r a l a s p e c t s of chemical r a d i a t i o n p r o t e c t i o n ? l Y l 2 Proceedings of t h e Second Symposium on P r o t e c t i o n a g a i n s t Radia t i o n s i n Space has been p r i n t e d ? = The r o l e of oxygen i n chemi~ w e l l as t h e conc a l r a d i o p r o t e c t i o n has been d i ~ c u s s e d ;as v e r s i o n of p r o t e c t i v e drug p r e c u r s o r s t o p r o t e c t o r s i n vivo.15 A bibliography on a n t i r a d i a t i o n d r u g s covering 1 9 5 9 - i 9 6 F E a v a i l a b l e .16 Radioprotection of Mammals - Chemical modification of t h e MEA s t r u c t u r e conti'nGs t o be worthwhile i n t h e s y n t h e s i s of new r a d i o p r o t e c t i v e a g e n t s , and some h i g h l y a c t i v e d e r i v a t i v e s have been reported. S u b s t i t u t i o n s on e i t h e r carbon, s u l f u r , o r n i t r o g e n have provided a c t i v e products, and i n t r o d u c t i o n of o t h e r f u n c t i o n a l groups, g e n e r a l l y c o n t a i n i n g s u l f u r , has a l s o been made. I n a few examples, i n c l u d i n g t h e condensation product of carbon d i s u l f i d e w i t h c y s t e i n e , an improvement over t h e t o x i c i t y of MEA or MEG has been found. An increased amount of a n t i r a d i a t i o n t e s t i n g has been observed f o r natu-
Chap. 3 2
Antiradiation
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rally-occurring compounds, and those compounds known to be physiologically active. Amino thiol derivatives. In a series of N-monosubsti-tuted 2-mercaptoethylamines, the 8-phenethyl derivative gave good protection to mice vs. 1000 r, and the B-2-thienylethyl derivative gave fair pro=cti~n?~No protection was shown by N-monosubstituted derivatives containing thioureido groups:8 and no protective activities were reported for N-monosubstituted Bunte salts of MEA carrying sulfone substituent~'~ Several 2-amino-2-alkyl-1,3-propanedithiols failed to show significant protection in mice, but L(+)-3-amino-4-mercapto-lbutanol gave good protection?' N Nf-Polymethylenebridging of the MEA molecule, giving XS( CHzIzNH( CH2)nNH( CH2)2SX, removed protective activity in mice where X was S03H, but provided good protection where X was P03HM and n=3 or 4?' Good protection vs. l O O O r in mice was also reportedz2 f o r the following MEA derivatives: S-2-amino2-methylpropylthiosulfuric acid (the N-decyl derivative was active vs. 750 r ) , S-2-amino-2-methylpropylphosphorothioic acid (the corresponding thiol was previously reported inactive), 2-amino-1-pentanethiol, and 2-amino-3-methyl-1-butanethiol. S-2-amino-1-pentylphosphorothioc acid showed fair protection, and the cyclic dithiocarbamate I gave good protection. Reaction of sultones with MEA and several thiones provided sulfonic acid inner salts, of which HS( CH2)2NH+( CH2)nSO; and its disulfide (where n-737 were protective in mice I -vs. 1000r?3 Corresponding butane derivatives (n-14) , Bunte s p t s (n=3,4) II S and dithiocarbonates, NH3( CH2)2SC(= 0)S(CHz)nSO;, were inactive, as well as were several isothiuronium sulfonates and heterocyclic sulfonates, which points to the same high degree of specificity as shown by other charged derivatives of MEA. Synthesis of the thiolsulfinate of MEA, NH2(CH2)2S(0)S(CH2)2NH2.2HC1, has been claimed:* as well as the preparation of 2-arninoethaneselenic acid25; no testing results were reported. A patent on 1-phenyl-2-aminoethanethiols as radiation protectors has appeared?8 A comparison of the protective effects in mice vs. 200-1000 rad of MEA and the Bunte salts of MEA, MPA, and Ksubstituted derivatives has been made?' The Bunte salts were claimed to give greater protection and possess about half the toxicity of MEA. A bisthiolsulfonate of N-acetyl MEA, A C N H ( C H ~ ) & ~ ~ ~ S ( C H ~ ) ~ S O ~ S ( C Hwas ~ ) ~found N H A ~to , be non-protective in mice?8 Unsymmetrical disulfides of MEA of type I1 were found active in mice vs. 1000 r, the most promising being zwitterions?' Good proEction was given where X was CO; or SO; and where the 2-minoethyl group was replaced by 2-pyridylmethyl.
02
332
Sect. VI
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Topics in C h e m i s t r y
Smi s sman, Ed.
No correlation was found between the nature of X, antiradiation potency, or resistance of the disulfides to disproportionation by either thermal o r photochemical I1 means. Where X was located para, no protective activity was shown?' Cyclic analogs of AET were examined in an attempt to find relationships between free SH content of the compound and reductive capacity, inhibition of tissue respiration, and radioprotective effect?l Where AET and APT gave 8 0 - l O O q 6 protection to mice vs. 730 r, alkylisothiourea derivatives had only a moderateeffect ( 3 5 - 5 0 $ ) , and aminoalkylmercaptoimidazolines gave only 2 O - 3 O $ protection. It was concluded that inhibition of tissue respiration does not depend on SH content, and that release of SH, reductive capacity, and inhibition of tissue respiration determine toxicity rather than protective ability. Other sulfur compounds. Several dithiocarbamates containingsulf'ide functions were non-protective in mice, as well as the S-benzyl dithiocarbamate of ethylenediamine?2 The S-trithiocarbonate N-dithiocarbamate of cysteine, 111, however, was found to give the same order of protection to mice vs. 800-1100 r as AET and was 2 - 3 S I1 fold less toxic than AET?3 It is believed to be converted in -S cs C H CHCO; ~ 3mf I vitro to the dithiocarbamateof cysteine, a compound not yet NHcs; 111 synthesized. A series of antibacterial sulfonamides showed varying degrees of protection in mice vs. 800 r , the best effects being shown by sulfanilamide (30~survival), sulfathiocarbamide (45%), and sulfamethazine (60$)?* Heterocycles. A series of N-alkylthiazolinium salts proved to be inactive in micei7 as was also a series of 2-aminothia~olines:~probably due to slow rates of hydrolysis to aminothiols. Various salts of 2-aminothiazoline showed varying degrees of protection in mice vs. 1090 r, the most effective being the succinate, fumaratc benzoate, and glutamate? Protection was somewhat less than that afforded by AET. Mice were protected (25% survival) vs. 800 r by 1-(p-ethoxyphenyl)-~-(D-arabinotetrahydroxy)bu~limida~oline-2-thi0ne?~ A series of s-triazoles, mesoionic s-triazoles, and l,3,4-oxadiazolium salts was screened in mice vs. 900 r without report of significant protection?8 Physiologically-active substances. In a series of p - a m m and p-nitro derivatives of procainamide tested in mice ys-. 880 r. none of the amino derivatives were protective. but several p-nitro compounds were?B Compound ?V provided 100% +
axs(CH2)2NH3
Chap. 32
Antir adiation
Foye
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survival. Among 14 organo-phosphorus compounds designed to form C-N-(C&)areversible antienzymeN O 2 0 I enzyme complexes and CH2- Ce H 5 Iv thus protect cholinesterase, only 2 (both thio hosphate esters) showed protective activity in mice vs. 750- 00 r f o No relation of anticholinesterase activity to raioprotective ability was found. 2-Aminoethylphosphoric acid was claimed to protect mice, however? Psychotropic drugs recently reported to be radioprotective include imipramine$2 taractan, Valium, tryptizol, and i n ~ i d o n ? ~ vs. 800 r. Substances Taractan provided 73% survival in mice known to stimulate turnover of NADP.H2, a physiological reducing agent, showed significant protection in mice vs. 900 r f 4 These included 4-hydroxybutyric acid and 6-phosph~luconolactone. Naturally-occurring substances. Significant radiation protection has recently been claimed for comrhmine. a nicotinic acid derivative$3 Ca pantothenate$ leicode1pkinidine$ tea catechols and a gallatetannin complex$8 isopropylarterenolt9 tyramine?' and methoxamine?' Among a group of commonly used antibiotics, the tetracyclines gave the best survival rate, which was attributed to an increase in metabolic activity?l Cyanocobalt-chlorophyllin has been patented as an antiradiation drug:2 and several articles have reported radiation protection from DNA, RNA, and derivatives distinct from postirradiation repair the rap^?^-^^ Other substances reported to show radioprotective effects include uridine but not cytidine monophosphate:6 polysaccharides extracted from typhoid and Proteus organism^?^ and typhoid-paratyphoid vaccineP8 Radiosensitizers The role of halogenated thymidine analogs in inducing radiosensitization of cells has been reviewed?' The common thiol-binding reagents sensitized mice to whole-body irradiation of 525 or 810 rads?' possible by removing endogenous protective thiols. Sensitization of mice or rats was also reported for nembutaltl nalorphine?' organic peroxide^?^ hemato orphyrinT4 riboflavine (increased by K)75 and cupric saltseg The sensitizing action of cupric salts was prevented by thiols. Sensitization of ascites lym hosarcoma NKLy cells was reported for ambunol, an aminophenol??
'
8
-
Radiosensitizing effects in bacteria have been found among hthalanilides phenaziniums, and isoindoliniums?8 Hadachloral hydrate and other halides (recidin5P vitamin KS," versed by MEA and cysteine)ll and organic n i t r o x i d e ~have ~~ also sensitized bacteria to ionizing radiation. A direct relation between ability to bind p-hydroxymercuribenzoate to
3 34
Sect. VI - T o p i c s i n C h e m i s t r y
Smi s s m a n , Ed.
thiols among several species of bacteria and radiosensitivity has been observed?" The sensitizing action of iodoacetamide on enzymes has been stated not to be the result of reaction with thiol groups, h ~ w e v e r ? ~ Radioprotective Dru s and Radiosensitizers & Radiotherapy of Tumors - Repeate&inistration of methyl ethyl ketone per=oxide increased the thera eutic effect of X-rays on lymphosarcoma in mice and possibly be decreasing catalase activity. Irradiation (2750 r) of transplanted rhabdomycosarcoma in mice gave complete remission in the presence of hematoporphyrin and its copper ~ o m p l e x ?Cysteine ~ thiosulfate protected organs but also exerted some protection on Crocker sarcoma in mice, thus diminishing the therapeutic effect?' The mitotic activity of MEA, AET, and serotonin in normal and malignant cells has been related to their protective effect^?^ Potentiating effects on irradiation of various tumors have been reported for actinomqcin Dye combination of cyclohexanol succinate and lysozyme,s 6-chlorothymineyo heterologous RNAY1 and menadione82 No protection was shown in experimental tumors by MEA, thiourea, serotonin, or iodoacetate; protection was given by 6-aminonicotinamide and menadiol diphosphate, however?" The distribution of AET in the or ans has been observed; tumors showed the lowest c~ncentration!~ Cysteamine-S-phosphate was found to give significant concentrations of MEA in 1 3 of15 tissues observed, including tumor tissuey5 whereas its methyl ester remained uncleaved in vivo. -Modes of Radioprotection - The major hypotheses of the modesof radioprotection, e.g., hypoxia, radical scavenging, and mixed disulfide formation, continue as the basis for much experimentation, but a very complex picture is emerging for the phenomenon of radioprotection. For the amino thiols, at least, free radical formation, oxygen, metal ions, energy transfer, and possibly mixed disulfide formation may all be involved. Bacq, however, favors a "biochemical shock'' mechanism for the amino thiols, in which fixing of the thiols to important macromolecules of the mitochondria liberates certain substances, possibly enzymes, which results in inhibition of carbohydrate utilization? In regard to anoxia or hypoxia as a major mechanism, most recent evidence has been unfavorable, particularly for the action of amino thiols. For instance, a correlation was observed between radioprotective activity and depressive effect of thymidine uptake in DNA synthesis, whereas anoxia did not inhibit the uptakef7 No relation was shown between radioprotective activity and ability to increase oxygen uptake in spleen, kidney, muscle, o r red blood cells:e and the intracellular oxred state in rats was unaltered even after massive doses of radiationFS Amino thiols, nitrite, and PAPP did not affect
Chap. 3 2
Anti r adia ti on
Foye
335 -
respiration of brain or liver mitochondria in either healthy or irradiated rabbits, but did in liver mitochondria -in vitr%O Post-irradiation exposure of rats to respiratory inhibitors, however, did reduce mortality and prevent loss of nuclear structure from thymocytes?l Evidence for the activity of some radioprotectors as inhibitors of free radical processes has appeared, and the subject has been reviewed?2 Involvement of MEA?= as well as of metal ions:4 in free radical formation in proteins and bacteria has been observed. It was also found that cysteine and glutathione could accept electrons from irradiated proteins, whereas cystine and non-sulfur compounds did not?5 Presence ofmetal ions, particularly cupric, had a protective effect for ribonuclease, presumably by interce ting electrons and preventing radical formation on the enzyme!' A protective effect of mucopolysaccharide polyanions and cysteine for trypsin and RNA, however, was not considered to be due to transfer of radiation energy to the protector^?^ Furthermore, substances known to react with H atoms or the aqueous electron did not protect hydrated E. coli cells from X-raysa8 Further examples that some radioprotectors cause an increase of endogenous thiol groups in various tissues have been reported during the past year. Amino thiols, cystamine, serotonin, compounds which lower 02 tension in tissues, and anoxia, bring about an increase in cellular thiol content, which, with the amino thiols, is 30-40 fold greater than that supplied by the protective agent?' This increase was also observed with diethyl dithiocarbamate, but not for disulfiram, its disulfi.de, which is also not protective>'' Decrease in both protein- and non-protein-bound thiol content has been observed with increasing doses of radiation?" Evidence for the binding of protective molecules to important cellular macromolecules continues to appear. The protection of GED against inactivation of trypsin, lysozyme, and aldolase was considered not due to radical scavenging, but to mixed disulfide formation>02 Protection of DNA by diamino disulfides was attributed to bound disulfide:03 and protection of lactate dehydrogenaselo4 and catalaselo5 by serotonin was also attributed to complex formation, possibly with the metal ions in the enzymes. Further indications of the importance of metal ions in radiation damage and protection have been found. Radiation death of L. delbrueckii, found to be due to the H202 formed, was prevented by catalase, as well as by EDTA indicating that oxidation by H202 is catalyzed by metal ions?6s Radioprotective properties of heavy metal ions, particularly Fei2 and Fef3,and MEA for plants was observed?07 Cuf2 was sensitizing, as it was for radiolytic deactivation of a-amylase and catalase>08 Radiation-induced oxidation of cytosine and uracil in presence of
Sect. VI
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- Topics in Chemistry
Smi s sman, Ed.
O2 produced radicals, but in the presence of Cuf2 and Fe+3, radicals were not formed.loS Whereas radical formation appears to be a major role for the amino thiols in radioprotection, protein binding o r reaction with metals probably occurs as well. At least, involvement in these reactions provides some basis for the necessity of the m i n e function, and for the high degree of structural specificity known for protection by amino thiols, which are not explained by radical trapping alone.
References 1. B. M. Tolbert, Natl. Acad. Sci.-Natl. Res. Council, Publ. No. 1355, 101 (1966). 2. W. Snipes, ed., "Electron Spin Resonance and the Effects
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of Radiation on Biological Systems", Natl. Acad. Sci.-Na tL Research Council, Washington, D. C., 1966. G. 0. Phillips, ed. , "Energy Transfer in Radiation Processes", Elsevier, New York, 1966. M. Ebert and A. Howard, eds. , "Current Topics in Radiation Research", V o l . 1, North Holland Publ. Co. , Amsterdam,l965. M. Ebert and A. J. Swallow, Adv. Chem. Ser.,50,289 (1965). L. A. Tinnov, G. A. Vasilfev, and E. A. Valldshtein, "Agents for Protection against Radiation, Handbook", Nauka, MOSCOW, 1964. H. J. Melching and C. Streffer, Progr. Drug Res.,~,ll(1966). P. Ciccarone, Comit. Nazl. Energia Nucl., Notiziario, 11,
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Chap. 3 2
Antiradiation
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-.3 37
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S m i s s m a n , Ed.
50. L. I. Tank and N. M. Slavachevskaya, Radiobiologiya, 6, 451 (1966). 51. T. Aleksandrov, I. Nikolov, D. Krustanov, and T. Tinev, Roentgenol. Radiol., 5, 45 (1966). 52. N. Kasugai, Japan pat. 18, 634 ( 165). 53. M. A. Tumanyan, N. G. Sinilova, A. P. Duplischeva, and K. K. Ivanov, Radiobiologiya, 6, 712 (1966). 54. N. Savkovic, J. Kacaki, and S.-Hajdnukovic, Nature, 211, 1179 (1966). 55. M. E. Roberts, C. Jones, and M. A. Gerving, Life. Sci. , 5, 1913 (1965). 56. M. Fukuda, M. Abe, Y. Tanaka, and M. Hashi, Strahlentherapie, 127, 146 (1965). A 57. . P. Duplischeva, K. K. Ivanov, and N. G. Sinilova, Radiobiologiya, 5, 318 (1966). 58. E. J. Ainsworth and F. A. Mitchell, Nature, 210, 321 (1966) 59 J. P. Kriss, US At. Energy Comm. Symp. Ser.,No.6,305(1966) 60. H. Moroson and H. A. Spielman, Intern. J. Radiation Biol., 11, 87 (1966). 61. C. Stuart and G. Cittadini, Minerva Fisioterap. Radiobiol., 10, 337 (1965). 62. G. Caprino and L. Caprino, ibid. , 10, gll (1965). 63. L. A. Tinnov, N. A. Kachurina, and-. I. Smirnova, Radiobiologiya, 6, 343 (1966). 64. G. CittadinT, B o l l . SOC. Ital. Biol. Sper., 41, 360 (1965). 65. St. Grigorescu, C. Nedelcu, and M. Netase, Raiobiologiya, 6, 819 (1966). 66. v. G. Yakovlev, ibid. , 4, 656 (1964). 67. G. G. Afanesfev, L. P. f;ipck?ina, I. I. Pelevina, Z. P. Khein, and N. M. Emanuel, Izv. Akad. Nauk SSSR, Ser. Biol.,
31, 890 (1966). 68. R. F. Pitillo, M. B. Lucas, and E. R. Bannister, Radiation Res. , 29, 549 (1966). 69. R. F. Pitillc E. R. Bannister, and E. P. Johnson, Can. J. Microbiol. , 12, 17 (1966). 70. H. K. Chandler, J. J. Licciardello, and S. A. Goldblith, J. Food Sci., 30, 893 (1965). 71. J. Burns, J. PFGarcia, M. B. Lucas, C. Moncrief, and R. F. Pitillo, Radiation Res. , 25, 460 (1965). 72. P. T. Emerson and P. Howard-Flanders, ibid. , &,54 (1965). 73. A. K. Bruce, US At. Energy Comm. , NYO-3319-6(1965). 74. M. Quintiliani and G. Gorin, Radiation Res. ,25,231(1965). 75. L. Cohen and S. Schwartz , Cancer Res. , 26, 1 F g (1966). 76. T. Zebro, Acta Med. Polona, 7, 83 (1966). 77. J. Kobayashi and F. Kawamura; Tokushima J. Exptl. Med. , 12, 24, 40, 45 (1965). 78. B. T. Aftonomos, P. M. St. Aubin, and J. F. Foley, Life
Sci., 5, 905 (1966). 79. A. Rocca, C. I e r o , and P. Mastroeni, Progr. Biochem. Pharmacol., 1, 400 (1965). 53, 44 (1966). 80. E. Magdon, Nzturwissenschaften, -
Chap. 32
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, G. Giudici, Strahlentherapie, 81. M. Pini, L. D ' A c ~ ~ z o and 128, 558 (1965). 82. S. A. Baisheva, Tr. Ka akhsk. Nauchn.-Issled. Inst. OnkoL i Radiol. 1, 308 (1965 . 83. R. Koch ana I. Seiter,Arzniemittel.-Forsch,l4,1018(1964). 84. H.Katayama,Nippon Igaku Hoshasen Gakkai Zasshi& 124(1965) 85. K.Pollack and O.M.Friedman,J. Med. Chem., 9, 622 (1966). 86. Z. M. Bacq, Bull. Acad. Roy. Med. Belg. , 6, 115 (1966). 87. H.A. B.Simons & E.M. Davis, Intern.J.Rad.Bioi. ,10,343 88. Y.Benabid and R.Rinaldi,Compt. Rend. Ser.D,263,683 89. D. Jamieson, Nature, 209, 361 (1966). 90. N. I.Bicheikina & E.F.~tsev,Radiobiologiya,6,8%( 1966). 211, 775 (1956). 91. J.F.Whitfield & H.Brohee, Nature, 92. N. M. Emanue1,E. B.Burlakova,K.E.Kruglyakova,& I.I.Sa ezkinskii,Izv.Akad.Nauk SSSR, Ser. Biol. , 31, 183 (19667. A. Saker, M. G. Ormerod, C. Dean, andP. Alexander, 93. Biochim. Biophys. Acta, 114, 169 (1966). '94.B.B.Singh & M.G.Ormerod,Intern.J.Rad.Bio1. 10,369(1966). 95. W. -C.Hsin,C. -L.Chang,M. -J.Yao,C. -H.Hua,& H. -C. Chin, Sci. Sinica (Peking), 15, 211 (1966). 96. P.Riesz,Biochem. mophys. Res. Commun. ,Q,273 (1966). 97. V.K.Ermolaev,Y. Cherepanov,G.D.Berdyshev,Y. N.Molin, and R.I.Salganik,Biofizika, 11, 805 (1966). 98. I.Johansen & P.Howard-Fl=ders,Radiation Rea,24,184(1965). 99. E. Y. Graevsky, M. M. Konstantinova, I. V. NekTasova, and 0. M. Sokolova, Nature, 212, 475 (1966). 100. J. H.Stromme & L.Eldjarn,=chem. Pharmacol.,15,287 (1966) . 101. L. Revesz and H. Modig, Ann. Med. Exptl. Biol. Fenniae (Helsinki), 44, 333 (1966). 102. G.Kollmann a x B.Shapiro, Radiation Res. ,27,474(1966). 103. E.Jellum, Intern. J. Radiation Biol. , 10,777 (1966), 104. W. Lohmann, A. J. MOSS, Jr. , W. B. G a r z d , and D. M. Woodall, Experientia, 22, 514 (1966). J. L. Sanders, B. J. Porter, 105. W. Lohmann, A. J. Moss,Jr., and D. M. Woodall, Radiation Res. , 29, 155 (1966). 106. D. Kayser, Z. Naturforsch., b 21, 167 (1966). 107. P. A. Vlasyuk, D. M. G r o d z i n m , and I. N. Gudkov, Radiobiologiya, 6, 591 (1966). 108. M. Anbar and A. bvitzki, Radiation Res. , 27, 32 (1966). log. J. Holian and W. M. Garrison, Nature, 212,394 (1966).
9
9-
3 40 -
Chapter 3 3 .
PHARMACEUTICS AND BIOPHARMACEUTICS Takeru Higuchi and Kenneth F. Finger School of Pharmacy, University of Wisconsin, Madison, Wisconsin William I. Higuchi School of Pharmacy, University of Michigan, Ann Arbor, Michigan
Basic investigations and developments in both pharmaceutics and biopharmaceutics area continue with increasing vigor. Although the bulk of published works still originates from academic institutions, an increasing proportion appears to be contributed by industrial organizations. General developments during the past year in these fields are summarized below. THERMODYNAMIC AND EQUILIBRIUM RELATIONSHIPS The tendency of polyethylene glycol (PEG) to form addition complexes with iodine was reported again by Hiskey and Catwell.' Unfortunately, the authors were apparently not aware of a more extensive study of similar systems carried out ten years earlier' which suggested formation of at least two types of adduct involving PEG, K+, I- and Iz. The more recent report differs in part from the earlier work in that PEGI, complex containing Iz/monomeric unit ratio of one is suggested among others. Bates, Gibaldi and Kanig3 have studied the relative solubilizing tendencies of four bile salts with respect to hexesterol, griseofulvin and glutethimide. The effect, which is ascribed entirely to micellar solubilization, was determined at several temperatures and at salt concentrations up to 0.6M. The most marked effect was noted with hexestrol and least for glutethimide. Connors and Mollica4 have compared the theoretical relationships of stability constants obtainable by solubility and other methods. Chelation equilibria involving five different tetracyclines with cupric copper have been examined by Benet and Goyan.5 These interactions appear to form essentially 2 : l (1igand:metal) complexes, the reaction showing large positive entropy changes.
Chap. 33
Biopharmaceutic s
Higuchi, F i n g e r a n d Higuchi
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DRUG STABILITY The past year was marked by relatively little activity in this area. -Wadke and Guttman' reported on the base induced degradation of 9-methylisoalloxazine under both aerobic and anaerobic conditions. The initial product formed appears to be a carbinol amine. Finholt et a17 have continued their investigation of anaerobic hydrolytic degradations of ascorbic acid with a study on the effect of metallic ions on the over-all rate. Although the reaction appears to be accelerated by doubly and triply charged species, the effect was surprisingly small. HETEROGENEOUS SYSTEMS Powders, Suspensions, and Emulsions - One of the most significant articles in recent years is that by Hiestands on particle-particle interaction in powders. The author has brought together much information from pharmaceutical research and from other disciplines and has perspectively assembled a rational treatise. The importance of plasticity and the true area of contact is clearly described. In addition, several novel methods for evaluating cohesion and adhesion of powder particles are described in this paper. Nash and Haeger9 have described the applications of the Zeta-Meter, a device which conveniently measures the electrophoretic mobility of suspension particles. The instrument appears to be useful in suspension and emulsion formulation work and in basic studies related to dispersed systems. Mima and Kitamori'' and Groves" have employed the Coulter Counter in studying the aggregation behavior of emulsions. This instrument continues to be useful for work of this type. Ho12 has described a modification of this instrument which involves the simultaneous sorting of the particles into 400 size ranges. This improvement significantly extends the applicability of this technique. Drug Release Rate Behavior - Desai et all3 have reported results of extensive studies on the release of druq from matrices. Taking the basic physical model approach and beginning with the Higuchi relati~nship'~ these authors have quantitatively investigated the influence of many factors upon the rate of release. The equation was also found by Lapidus and Lordi15 to apply to a system having hydrophillic gum as the matrix. Goldberg et al" have continued their extension of the Japanese workI7 on utilizing melts to increase dissolution
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rates of drugs. Succinic acid as well as urea was used as the vehicle in these studies. Since at elevated temperatures the dicarboxylic acid readily cyclizes to form succinic acid, some of the results should, perhaps, be re-examined. BIOPHARMACEUTICS The pharmacological activity, efficacy, and toxicity of an administered medicament may be profoundly affected by the physic-chemical properties of the drug and the drug dosage form. Thus, such parameters as solubility, particle size, diffusional characteristics, availability and rate of dissolution of the drug have been the areas emphasized in most biopharmaceutical studies. The effect of these parameters on drug absorption is the subject of this review. Diffusional Characteristics - The everted intestinal sac technique was employed by Aguiar and Fifelski” to quantitate the absorption of flufenamic acid. These workers determined the rate of permeability of flufenamic acid through the intestinal wall of the golden hamster, in vitro, and interpreted their results in terms of Fick’s first law of diffusion. They observed a -linear relationship between the concentration of the drug employed and the rate of intestinal permeation, thus establishing that the transport of flufenamic acid through the gut was by passive diffusion. By varying the pH of the external (mucosal) media, they found that the rate of permeation was inversely proportional to the degree of ionization, thus supporting the hypothesis that only the unionized moiety permeates the biological membrane. While most drug systems evaluated have shown passive diffusional characteristics, Levy and Jusko19 have reported that the oral absorption of riboflavin in man possesses characteristics indicative of specialized transport mechanisms. The evidence in support of such a conclusion was based on the finding that as the dose of riboflavin was increased, the per cent absorbed (based on urinary recovery) decreased. This effect was observed only in fasted patients and was not observed when riboflavin was administered with a meal. The authors suggest that the presence of food in the alimentary tract delays the transit time of riboflavin, thus keeping it in the presence of absorptive sites for longer periods of time. In an interesting study utilizing tritiated mineral oil, Ebert, Schleifer, and HessZo have shown that contrary to previous opinions, a small but significant amount of mineral oil is absorbed from the alimentary tract following oral
Chap. 33
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Higuchi, F i n g e r and Higuchi
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administration. Their findings, employing doses consistent with those usually utilized for laxative purposes in humans, indicated that approximately 1.5% of the administered dose was absorbed unchanged with an additional 1.5% appearing in the carcass of the animals but arising from non-mineral oil sources. The origin of the non-mineral oil sources was not proved but may have arisen from exchange reactions prior to or after absorption or from non-polar metabolic products of mineral oil metabolism. The authors noted that once absorbed, the mineral oil was slow in leaving the body. The elimination curves illustrated a dephasic characteristic, the more rapid component resulting in a reduction of the mineral oil content of the body from 1.5% of the administered dose down to 0.3% in approximately two days. The slower component of elimination reduced the content further down to 0.1% in 21 days. In agreement with studies previously reported,21 Ebert et a1 found that emulsification of the mineral oil greatly facilitated the oral absorption of mineral oil. Although a mechanism to rationally explain their findings is not presented, Green et a122 have reported data substantiating their previous observations on the influence of cholinesterase inhibitors on the oral absorption of sulfonamides.23 These workers found that the four-hour plasma levels of sulfacetamide, sulfonilamide and sulfaguanidine were enhanced when the rats were pre-treated with neostigmine as compared to those plasma levels found in the controls. The earlier studies had indicated that this enhancement was not blocked by atropine, thus minimizing the possibility of an increased blood flow at the absorption site as being the mechanism for enhanced absorption. While perhaps not representing a major factor in the absorption of drugs through the intestinal membranes, the role played by cholinergic systems is worthy of further elucidation. It would be desirable, in this regard, to ascertain whether or not other drug systems are similarly affected by inhibitors of cholinesterase. Particle Size - The influence of particle size on the overall absorption of medroxyprogesterone in man has been studied by Smith, Pulliam and Forist.24 Utilizing an eight-hour urinary excretion of metabolite as an index of the absorption of drug, they found that 2 . 2 3 times as much medroxyprogesterone was absorbed from the micronized formulation as was obtained from the non-micronized drug formulation. While these data could also be interpreted to indicate only an increased rate of absorption with no change in the total amount of drug absorbed, the authors feel that because of the finite transit' time of the drug through the gastrointestinal tract, and the 1 previously reported excretion studies of Helmreich and Huseby,25 these data are best interpreted to indicate an
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enhanced total absorption of the drug. Drug Interactions and Availability - The role of surfactants in modifying the availability and/or the absorbability of various barbiturates via the rectal route was the subject of a report by Fincher, Entrekin, and Hartman.26 These workers, employing a petrolatum-paraffin base suppository, added various surfactants of known HLB values, and determined the effect of the incorporated barbiturate on the rate of respiration of the rabbit. The authors concluded that while the inclusion of a surfactant enhanced the rate of absorption of the barbiturates in some cases, it could also bind the drug, thus making it less available for the absorption process. The chemical type of drug and surfactant were deemed more important than either the apparent HLB of the system or the relative distribution coefficient. Similarly, Levy, Miller, and Reuningz7 found that by adding various concentrations of polysorbate 80, a nonionic surfactant, to aqueous drug solutions, the absorbability of a barbiturate could be both increased or decreased. These authors employed goldfish as the test species and investigated the lethality times of low molecular weight alcohols and two barbiturates. The inclusion of the polysorbate 80 had no effect on the lethality times of the alcohols while it was concluded that low concentrations of the surfactant (below the critical micelle concentration) enhanced the absorption of sodium secobarbital,and higher concentrations decreased the rate of absorption of the barbiturate. In both this study and the work of Fincher et a1,26 the possibility of drug-surfactant interactions detrimental to the availability of the drug for absorption is a probability worthy of further study. Singh et allz8 studied the interaction of various barbiturates with polyethylene glycol 4000 and found that phenobarbital formed a complex with the glycol. The solubility of the complexed phenobarbital was much lower than the intrinsic solubility of phenobarbital in the absence of polyethylene glycol 4000. Utilizing the everted sac technique to measure the rate of intestinal permeability, they found that the decreased solubility greatly decreased the rate of permeation. The other three barbiturates'studied, pentobarbital, barbital, and barbituric acid, did not interact with the polyethylene glycol 4000 and the inclusion of this material did not decrease their rates of intestinal permeation. Sorby and LiuZ9 investigated the effect of adsorbents on the intestinal absorption of promazine in humans. The
Chap. 33
B i o p h a rm a ce u t i c s
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results of this study point out the importance of knowing the reactivity of the drug with materials either contained in the dosage form or administered as concurrent therapy. They found that an antidiarrhea mixture containing attapulgite and pectin had a very strong affinity for promazine by in vitro adsorption techniques. When promazine was administered to humans along with the attapulgite-pectin mixture, the rate and extent of gastrointestinal absorption of promazine was decreased. Influence of Dosaqe Form - The oral absorption of indoxole, an experimental non-steroidal anti-inflammatory compound, was studied by Wagner, Gerard, and Kaiser.30 These workers employed four different dosage forms of indoxole in their studies, an emulsion, soft elastic capsules, an aqueous suspension, and a hard capsule. They found that solutions of the drug (the emulsion and the soft elastic capsule) gave superior absorption characteristics as measured by drug plasma levels than did the solid drug forms (the suspension and the hard capsule). It would appear that indoxole represents another case where dissolution rate and/or drug availability is the rate determining process in the over-all absorptive process. References 1. 2.
3. 4. 5. 6. 7.
8. 9.
10. 11. 12. 13. 14. 15.
C. F. Hiskey and F. F. Cantwell, J. Pharm. Sci., 55, 166 (1966). D. E.' Guttman and T. Higuchi, J. Am. Pharm. Assn. Sci. Ed. 44, 668 (1955). T. B z e s , M. Gibaldi, and J. L. Kanig, J. Pharm. Sci., 55, 191, 901 (1966). K. A. Connors and J. A. Mollica, ibid, 55, 772 (1966). L. Z . Benet and J. E. Goyan, ibid, 55, -84 (1966). D. A. Wadke and D. E. Guttman, i b i d T z , 1088, 1363(1966). P. Finholt, H. Kristiansen, L. Krowczynski, and T. Higuchi, ibid, 55, 1435 (1966). E. N. Hiestand, J. Pharm. Sci., 55, 1325 (1966). R. A. Nash and B. E. Haeger, J. %%arm. sci., 55, 829 (1966). H, Mima and N. Kitamori, J. Pharm. Sci., 55, 44 (1966). 305 (1966). M. J. Groves, J. Pharm. Pharmacol., N. F. H. Ho and W. I. Higuchi, Abstracts of the 1966 Meetings, Acad. Pharm. Sci., Dallas. S. J. Desai, P. Singh, A. P. Simonelli, and W. I. Higuchi, J. Pharm. Sci., 55, 1224, 1230, 1235 (1966). T. Higuchi J. Pharm. Sci., 52, 1145 (1963). H. Lapidus and N. G. Lordi, ibid,55, 840 (1966).
=,
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346 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30.
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H . G o l d b e r g , M. G i b a l d i , and J . L. K o n i g , i b i d , 55, 4 8 2 , 487 ( 1 9 6 6 ) . K. S e k i g u c h i , N. O b i , and Y. U e d a , C h e m . Pharm. B u l l . , 12, 1 3 4 (1964). A. J . A g u i a r , a n d R . J . F i f e l s k i , J . P h a r m . S c i . , 55, 1387 (1966). G. Levy and W. J . J u s k o , J . Pharm. S c i . , 55, 285 ( 1 9 6 6 ) . A. G. E b e r t , C . R . S c h l e i f e r , a n d S . M. H e s s , J . P h a r m . S c i . , 55, 923 ( 1 9 6 6 ) . J . G. Wagner, E . S . G e r a r d , and D . G. K a i s e r , C l i n . Pharmacol. Therap., 2, 929 ( 1 9 6 6 ) . V. A . G r e e n , T . M. G l e n n , S . J . S t r a d a , and G. M e d i n a , J . Pharm. S c i . , 55, 516 ( 1 9 6 6 ) . D . L . S m i t h , A. L. P u l l i a m , and A. A. F o r i s t , J . P h a r m . S c i . , 55, 519 ( 1 9 6 6 ) . I b i d . , 398. I b i d . , 403. J. H. F i n c h e r , D. N . E n t r e k i n , and C . W. H a r t m a n , J . Pharm. S c i . , 55, 23 ( 1 9 6 6 ) . G. Levy, K. E . M i l l e r , and R . H. R e u n i n g , J . Pharm. S c i . , 55, 394 (1966). P . S i n g h , J . K . G u i l l o r y , T . D . Sokoloski, L . Z . B e n e t , and V . N . B h a t i a , J . Pharm. S c i . , 55, 63 ( 1 9 6 6 ) . D . L . Sorby and G. L i u , J . Pharm. S c i . , 55, 5 0 4 ( 1 9 6 6 ) . J . G. Wagner, E . S . G e r a r d , and D . G. K a i s e r , C l i n . Pharmacol. Therap., 2, 610 ( 1 9 6 6 ) . A.
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347
Chapter 34. The U s e of S u b s t i t u e n t C o n s t a n t s i n Drug Design Corwin Hansch, Pomona C o l l e g e , Claremont, C a l i f o r n i a The s u b j e c t of s t r u c t u r e - a c t i v i t y r e l a t i o n s i n m e d i c i n a l chemistry is almost boundless. Few p a p e r s a r e now published without some d i s c u s s i o n of t h i s problem. The work considered i n t h i s review i s l i m i t e d t o t h a t concerned w i t h mathematical c o r r e l a t i o n s between s t r u c t u r e and activity. The u s e of physical-chemical r e f e r e n c e systems t o s e r v e a s scales w i t h which one could d i s c u s s i n q u a n t i t a t i v e t e r m s t h e r e l a t i o n between b i o l o g i c a l a c t i v i t y and chemical s t r u c t u r e e x c i t e d g r e a t i n t e r e s t a t t h e t u r n of t h e c e n t u r y . C. R i c h e t , J . Traube, H . Fiihner and e s p e c i a l l y H . Meyer and E. Overton gave t h r u s t t o t h i s movement. It was observed, almost e n t i r e l y i n a l i p h a t i c systems, t h a t as one i n c r e a s e d t h e c h a i n l e n g t h i n a homologous series a r e g u l a r i n c r e a s e i n a s t a n d a r d b i o l o g i c a l response o c c u r r e d . L i n e a r r e l a t i o n s between a s t a n d a r d r e s p o n s e and t h e number of carbon atoms i n t h e c h a i n , w a t e r s o l u b i l i t y , s u r f a c e t e n s i o n lowering a b i l i t y , vapor p r e s s u r e and o i l - w a t e r p a r t i t i o n c o e f f i c i e n t s were o f t e n found i n many d i f f e r e n t tests. An example of t h i s t y p e of c o r r e l a t i o n u s i n g p a r t i t i o n c o e f f i c i e n t s coming from t h e work of Overton is : l o g 1 / C = 0.858 logP
+
0.837
n = 28
r = 0.978
(1)
I n eq 1, C r e p r e s e n t s t h e molar c o n c e n t r a t i o n of v a r i o u s a l c o h o l s , k e t o n e s and esters producing i s o n a r c o s i s i n t a d p o l e s , P i s t h e octanol-water part i t i o n c o e f f i c i e n t , n i s t h e number of d a t a used i n f i n d i n g t h e c o n s t a n t s v i a t h e method of least s q u a r e s , and r i s t h e c o r r e l a t i o n c o e f f i c i e n t . The c o n s t a n t s i n eq 1 are s l i g h t l y d i f f e r e n t from t h o s e published' and t h e c o r r e l a t i o n is a l i t t l e b e t t e r because of t h e u s e of imprpved P v a l u e s . An important advance w a s made by Ferguson2y3 who showed t h a t t h e following generalization holds. ci = kAi l / n
I n eq 2 , Ci is t h e c o n c e n t r a t i o n of t h e ithmember of a series producing a n e q u i v a l e n t response, k and n are t h e c o n s t a n t s , and A. i s a p h y s i c a l 1 chemical d i s t r i b u t i o n c o n s t a n t of t h e above mentioned k i n d . Ferguson p o i n t e d o u t t h a t f o r n o n s p e c i f i c n a r c o t i c s i n s t a t e s of e q u i l i b r i u m , biol o g i c a l a c t i v i t y i s r e l a t e d t o thermodynamic a c t i v i t y . Ferguson's approach was extended by Brink and Post-._-nak4 and i t i s now e v i d e n t t h a t t h e r e a r e many i n s t a n c e s where e q u a l d e g r e e s of n a r c o s i s a r e caused by molecules having e q u a l thermodynamic a c t i v i t i e s . Other approaches t o e x p l a i n i n g t h e e f f e c t of n a r c o t i c a c t i v i t y i n terms of physical-chemical parameters are t h o s e of M c G ~ w a n ~and - ~ Mullinsg McGowan u s i n g parachor and Mullins u s i n g H i l d e b r a n d ' s s o l u b i l i t y parameter and m o l a l volume, have
.
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Sect. VI
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S m i s sman, Ed.
assembled e v i d e n c e t o s u p p o r t t h e view t h a t t h e m o l e c u l a r volume of t h e n a r c o t i c is of c r i t i c a l importance i n d e t e r m i n i n g n a r c o s i s . PaulinglO and Miller'' have s u g g e s t e d t h a t a n e s t h e t i c potency i s r e l a t e d t o t h e a b i l i t y of a n e s t h e t i c s t o form h y d r a t e s . M i l l e r , Paton and Smith' and o t h e r s have c r i t i c i z e d t h e Pauling-Miller view. Agin, Hersh and Holtzman14 have shown t h a t eq 3 g i v e s an e x c e l l e n t c o r r e l a t i o n f o r t h e r e l a t i o n between minimum b l o c k i n g c o n c e n t r a t i o n (MBC) of 3 9 l o c a l a n e s t h e t i c s i n f r o g s a r t o r i u s muscle w i t h p o l a r i z a b i l i t y (a) and t h e i o n i z a t i o n p o t e n t i a l (I) of t h e d r u g s .
Zahradnik15, i n a s y s t e m a t i c s t u d y u s i n g mice and c a r e f u l l y cont r o l l e d c o n d i t i o n s , developed a set of c o n s t a n t s f o r a l k y l groups from t h e l i n e a r Hammett-like p o s t u l a t e thattftog (T./T,,) = aB where T r e p r e 1 s e n t s t h e molar c o n c e n t r a t i o n of t h e i member of a set of a l i p k a t i c cong e n e r s producing a s t a n d a r d b i o l o g i c a l r e s p o n s e and T~~ i s t h e concentrat i o n of t h e e t h y l d e r i v a t i v e . 6 i s a c o n s t a n t c h a r a c t e r i s t i c of t h e subs t i t u e n t ( R of RX) and a i s a c o n s t a n t c h a r a c t e r i s t i c of t h e system. The c o n s t a n t B w a s determined f o r 25 R groups and a w a s e v a l u a t e d f o r 39 d i f f e r e n t b i o l o g i c a l systems. While t h i s s i n g l e parameter approach works w e l l f o r i n h i b i t o r y s t u d i e s of homologous groups of a l i p h a t i c compounds where h i g h l y s p e c i f i c e l e c t r o n i c and s t e r i c e f f e c t s are n o t c r i t i c a l , i t h a s n o t been extended t o more complex systems. The above i d e a s have provided i n s i g h t i n t o n o n s p e c i f i c b i o l o g i c a l i n h i b i t i o n s ; however, t h i s knowledge h a s n o t been of g r e a t h e l p i n t h e des i g n and m o d i f i c a t i o n of d r u g s of h i g h s p e c i f i c i t y . Two approaches have been emerging i n r e c e n t y e a r s t o supplement t h e m e d i c i n a l c h e m i s t s ' i n t u i t i o n on t h e e f f e c t of s u b s t i t u e n t v a r i a t i o n on drug a c t i v i t y . I n one aproach de novo s u b s t i t u e n t c o n s t a n t s have been d e r i v e d by simply f i n d i n g t h e " b e s t numbers'' t o go w i t h g i v e n s u b s t i t u e n t s on a p a r t i c u l a r drug a c t i n g i n a s t a n d a r d t e s t . The o t h e r approach h a s used s u b s t i t u e n t cons t a n t s d e r i v e d from model n o n b i o l o g i c a l systems. The f i r s t work on t h e former of t h e s e two t r a c k s a p p e a r s t o b e t h a t of B r u i c e , Kharasch and Winzlerl working w i t h t h y r o x i n e d e r i v a t i v e s . T h e i r ,approach has been s t a t e d i n more g e n e r a l terms by F r e e and Wilson17. The method can b e ill u s t r a t e d w i t h t h e i r example f o r a s e t of t e t r a c y c l i n e (I) a n a l o g s . The r e l a t i v e b i o l o g i c a l a c t i v i t y f o r each d e r i v a t i v e c a n be formulated a s t h e l i n e a r combination of t h e c o n t r i b u t i o n of each of t h e groups r e p r e s e n t e d by X , Y and R: Biological a c t i v i t y = p
+
a[X.] 1
+
bEY.1 1
(1)
+ c[Ril One can w r i t e a set of s i m u l t a n e o u s e q u a t i o n s , one f o r each compound t e s t e d , t h e s o l u t i o n of which g i v e s t h e c o n t r i b u t i o n t o t h e a c t i v i t y f o r each a [ X i ] , e t c . T a b l e I l i s t s t h e r e s u l t s f o r t h e t e t r a c y c l i n e s .
Table I X
R
a[Hl a[CH3]
75
b[C11
84
-112
b[Brl
-16
349 -
Hansch
Drug Design
Chap. 3 4
Y
c “Hz
I
123
c [ CH3CONHI
18
!J =
161
-218 Of t h e t o t a l of 1 8 p o s s i b l e d e r i v a t i v e s r e s u l t i n g from d i f f e r e n t combinat i o n s of R, X and Y , 10 had been t e s t e d . Presumably, a c t i v i t i e s f o r t h e o t h e r e i g h t can b e c a l c u l a t e d from t h e s u b s t i t u e n t c o n s t a n t s i n T a b l e I . The method i s of g r e a t e s t v a l u e when a l a r g e group of d e r i v a t i v e s and f u n c t i o n s i s i n v o l v e d . There a r e of c o u r s e many o b j e c t i o n s t h a t come t o mind i n c o n s i d e r i n g t h e above t e c h n i q u e . Modern c h e m i s t r y h a s l o n g recognized t h e g r e a t importance of s t e r i c and e l e c t r o n i c e f f e c t s of s u b s t i t u e n t s on r a t e and e q u i l i b r i u m p r o c e s s e s 1 8 . From t h e Meyer-Overton work and from more r e c e n t t h e hydrophobic bonding power of funct i o n a l groups i s s e e n t o b e a v e r y i m p o r t a n t s u b s t i t u e n t e f f e c t . These t h r e e e f f e c t s a r e lumped i n t o each of t h e c o n s t a n t s under R, X and Y of T a b l e I . Hence i t would seem t h a t i n g e n e r a l , c o n s t a n t s d e r i v e d f o r one s e t of congeners w i l l n o t b e u s e f u l f o r a n o t h e r set c a u s i n g a d i f f e r e n t b i o l o g i c a l r e s p o n s e . N e v e r t h e l e s s , t h i s e m p i r i c a l method of d e r i v i n g cons t a n t s f o r t h e r e l a t i v e e f f e c t s of chemical groups on b i o l o g i c a l a c t i v i t y i s bound t o b e more h e l p f u l i n t h e long run t h a n unguided i n t u i t i o n . Purc e l l 3 4 has been s t u d y i n g t h e Free-Wilson method. Some i n f o r m a t i o n i s a l r e a d y i n hand t o show t h a t such e m p i r i c a l cons t a n t s are r e l a t e d t o more fundamental p a r a m e t e r s . C i l e n t o and Berenholc have shownz6 t h a t t h e r e i s a good l i n e a r c o r r e l a t i o n between f(X) o b t a i n e d f o r 1 6 t h y r o x i n e a n a l o g s (11) and t h e n e g a t i v e l o g a r i t h m of t h e l i f e t i m e of t h e phosphorescent s t a t e ( e q u i v a l e n t t o t h e t r i p l e t t o s i n g l e t t r a n s i t i o n i n n a p h t h a l e n e a n a l o g s ) f o r t h e f i v e f u n c t i o n s where X = H , CH3, C l , B r , I. They conclude t h a t t h e s t r o n g T+S t r a n s i t i o n i n d i i o d o t y r o s i n e and t h y r o x i n e d e r i v a t i v e s makes t h e s e compounds v e r y e f f i c i e n t i n t h e t r a n s f e r of t r i p l e t - s t a t e energy. Using t h e subx s t i t u e n t o f o r t h e e l e c t r o n i c e f f e c t and / \ H \ n f o r t h e hydrophobic e f f e c t z 7 of /WH,CHNH,COOH .-.\-R /-.\s u b s t i t u e n t s , i t i s s e e n from eq 4 t h a t f(X’) d e r i v e d by B r u i c e e t a l . x’/ X/ (11) i s i n f a c t r e l a t e d t o t h e s e more fundamental c o n s t a n t s .
\.-.
<-
f(X’)
It h a s of t h y r o x i n e t h e u s e of B been shown30
-
= 0.3081~
0.5640
- 1.672
n = 7
r
=
0.934
(4)
been shown28 t h a t IT and o c a n b e used t o r a t i o n a l i z e t h e SAR a n a l o g s and J ~ r g e n s e n *h~a s t e s t e d t h e p r e d i c t i v e v a l u e of and IT w i t h a t e r t - b u t y l a n a l o g of t h y r o x i n e . It h a s a l s o t h a t Zahradnik‘s $ c o n s t a n t s a r e l i n e a r l y r e l a t e d t o IT.
Kopeck; and Bozek31,32 have a l s o been s t u d y i n g t h e u t i l i t y of emp i r i c a l s u b s t i t u e n t c o n s t a n t s i n an i n v e s t i g a t i o n of t h e t o x i c i t y of d i s u b s t i t u t e d benzenes. I n t h e i r e q u a t i o n (5) t h e y have used a n i n t e r a c t i o n
3 50 -
Sect. VI
-
Topics i n Chemistry
Smi s sman, Ed.
term of t h e t y p e d i s c u s s e d by Miller33 f o r t h e l i n e a r combination of terms i n t h e f o r m u l a t i o n of m a t h e m a t i c a l m o d e l s .
I n eq. 5 , HH r e p r e s e n t s benzene and XY a d i s u b s t i t u t e d d e r i v a t i v e . Quite good c o r r e l a t i o n s w e r e o b t a i n e d u s i n g eq 5 f o r n o n s p e c i f i c t o x i c i t y . The c o n s t a n t bX i s s t a t e d t o b e l i n e a r l y r e l a t e d t o f(X’) of Bruice e t a l . Puree1136 , following t h i s g e n e r a l approach, h a s s t u d i e d amides which are i n h i b i t o r s of c h o l i n e s t e r a s e . P u r ~ e 1 Y 136~ and ~ co-workers have a l s o i n v e s t i g a t e d a v a r i e t y of p h y s i c a l chemical parameters t o r a t i o n a l i z e t h e SAR f o r these inhibitors. A f t e r t h e r a t h e r i n t e n s e work on t h e c o r r e l a t i o n of b i o l o g i c a l act i v i t y w i t h p a r t i t i o n c o e f f i c i e n t s of t h e e a r l y y e a r s of t h i s c e n t u r y had reached a s t a n d s t i l l , new hope f o r r a t i o n a l i z i n g t h e b i o l o g i c a l a c t i v i t y of o r g a n i c compounds appeared i n t h e work of H a m m e t t 3 7 . The H a m m e t t equat i o n and o t h e r v a r i a t i o n s of i t 1 a ~ 3 a have proved t o be v e r y s u c c e s s f u l i n c o r r e l a t i n g chemical r e a c t i v i t y w i t h t h e e l e c t r o n i c o r s t e r i c e f f e c t s of s u b s t i t u e n t s f o r t h e r e a c t i o n s of o r g a n i c compounds i n homogeneous solut i o n s . Although a good many a t t e m p t s have been made39’47 t o apply t h e H a m m e t t e q u a t i o n t o biochemical systems, t h e r e s u l t s have, w i t h few except i o n s , been d i s a p p o i n t i n g . Such a n e x c e p t i o n i s seen i n t h e enzymatic hyd r o l y s i s of phenyl s u l f a t e s 3 9 from which eq 6 r e s u l t s 2 4 . l o g l / K m = 0.9300
+
2.522
n = 10
r = 0.931
(6)
I n eq 6, K i s t h e Michaelis c o n s t a n t . Good c o r r e l a t i o n w i t h o w a s a l s o The b e s t l i n e a r r e l a t i o n s w i t h o have been found uso b t a i n e d wyth Vmax. i n g more o r less pure enzymes. The l a c k of s u c c e s s w i t h o i n biochemical s t e r i c i n t e r a c t i o n s of s u b s t i t systems h a s g e n e r a l l y been a t t r i b ~ t e dt o~ ~ u e n t s w i t h t h e enzyme o r l i p o p r o t e i n membranes. Recent work21-25 would i n d i c a t e t h a t w h i l e s t e r i c i n t e r a c t i o n s are extremely i m p o r t a n t , t h e conc e p t of lock-and-key f i t of enzyme and s u b s t r a t e h a s been over-emphasized a t t h e expense of hydrophobic bonding. The importance t o t h e m e d i c i n a l chemist of t h e more f l e x i b l e c h a r a c t e r of enzymes which is emerging from t h e work of Koshlandlt9 and others5O h a s been analyzed by Belleau51. A most important new concept f o r t h e d e s i g n e r of drugs is t h a t of t h e hydrophobic bond19 y 2 0 ,s2. The view of Hansch and co-workers is t h a t i f a s u i t a b l e parameter can be formulated f o r t h i s , t h e n by means of t h e w e l l known c o n s t a n t s 1 8 o , a+, O-, o*, and E,, many of t h e powerful t o o l s of p h y s i c a l o r g a n i c chemistry might b e brought t o b e a r on m e d i c i n a l chemic a l problems. To t h i s end octanol-water p a r t i t i o n c o e f f i c i e n t s (P) have Y ~ a d~ d i t. i v e - c o n s t i t u t i v e been s t u d i e d as a r e f e r e n c e standard1 Y ~ ~ The n a t u r e of l o g P and IT (IT = logP - logP where P r e f e r s t o a p a r e n t moleX H H c u l e and P t o a d e r i v a t i v e ) means t h a t from a r e l a t i v e l y few v a l u e s Of X l o g P, many o t h e r s can b e calculated1,24,27,53,54. The u s e f u l n e s s of t h e s e parameters f o r measuring binding of n e u t r a l molecules w i t h p r o t e i n s i s i l l u s t r a t e d i n eq 7 - 2 .
Drug Design
Chap. 34 l o g 1 / C = 0.71 logP l o g 1 / C = 0.58 logP
+ +
Hansch
351 -
1.51
n = 17
r = 0.950
(7)
2.40
n = 4
r = 0.961
(8)
n = 19
r
(9)
+
l o g 1 / C = 0 . 6 8 1 ~ 3.48
= 0.962
I n eq 7-9, C is t h e molar c o n c e n t r a t i o n of compound n e c e s s a r y t o produce a 1-to-1 complex w i t h bovine hemog1obin2l (eq 7 ) and bovine serum albumin (eq 8 and 9 ) . Equation 7 c o r r e l a t e s t h e binding of 1 7 m i s c e l l a n e o u s compounds ( e . g . , phenols, a n i l i n e s , naphthalene) and eq 8 c o r r e l a t e s t h e binding of 4 barbiturate^^^. I n eq 9 , t h e comparative c o n s t a n t IT i s used55 t o c o r r e l a t e t h e binding of phenols by serum albumin. The s l o p e s of t h e t h r e e e q u a t i o n s a r e s u r p r i s i n g l y c l o s e , i n d i c a t i n g t h a t t h e binding of n e u t r a l molecules t o two d i f f e r e n t p r o t e i n s can be q u a n t i t a t i v e l y def i n e d u s i n g l o g P o r IT as hydrophobic bonding c o n s t a n t s . For t h e s e s i t u a t i o n s no h i g h l y s p e c i f i c s t e r i c o r e l e c t r o n i c parameters a r e n e c e s s a r y t o rationalize the results. Going t o t h e n e x t more complex s i t u a t i o n , t h a t of enzymic r e a c t i o n s , i t can be shown t h a t t h e l i n e a r combination of IT and 0 can account f o r t h e s u b s t i t u e n t e f f e c t s i n t h e h y d r o l y s i s of phenyl g l u c o s i d e s by e m ~ l s i n ~ ~ . Using r e g r e s s i o n a n a l y s i s , eq 10-13 are d e r i v e d t o i l l u s t r a t e how one can f a c t o r s u b s t i t u e n t e f f e c t s on a biochemical r e a c t i o n . P a r a Groups
Meta Groups
+ 0.331~+
l o g Ke = 0.52a
2.03
l o g Ke =
0.620
+
+ 1.63 0 . 1 2 ~+ 0.96 +
1.80
l o g Ke = 0.95a l o g Ke =
1.59
n = 8
r = 0.753
(10)
n = 8
r = 0.921
(11)
n = 6
r = 0.949
(12)
n = 6
r = 0.963
(13)
Ke r e p r e s e n t s t h e e q u i l i b r i u m c o n s t a n t € o r t h e enzyme s u b s t r a t e complex. Comparison of eq 10 and 11 f o r t h e p a r a d e r i v a t i v e s i n d i c a t e s t h a t complex formation depends on both e l e c t r o n i c and hydrophobic f a c t o r s . The c o r r e l a t i o n c o e f f i c i e n t i s much b e t t e r and s t a t i s t i c a l l y q u i t e s i g n i f i c a n t f o r eq 11. The p o s i t i v e s i g n s of t h e c o e f f i c i e n t s f o r IT and a i n d i c a t e t h a t l i p o p h i l i c and e l e c t r o n - a t t r a c t i n g groups promote complex formation. Comp a r i n g eq 12 and 13, one f i n d s t h a t f o r meta isomers hydrophobic bonding i s a p p a r e n t l y n o t p o s s i b l e . N o s i g n i f i c a n t improvement i n c o r r e l a t i o n res u l t s on t h e i n t r o d u c t i o n of t h e v term. A s i m i l a r set of e q u a t i o n s was d e r i v e d 5 6 t o show t h e s u b s t i t u e n t e f f e c t on t h e h y d r o l y s i s rate c o n s t a n t k3. Equally good c o r r e l a t i o n s were obtained except i n t h i s s t e p ; as one might e x p e c t , t h e c o e f f i c i e n t w i t h IT h a s a n e g a t i v e s i g n . T h i s i n d i c a t e s t h a t hydrophobic bonding slows down d e s o r p t i o n of t h e cleaved p r o d u c t s . S i n c e good c o r r e l a t i o n s w e r e o b t a i n e d i n eq 11 and 13 w i t h o u t t h e u s e of s t e r i c c o n s t a n t s , i t is assumed t h a t t h e s e are unimportant, a t least f o r f u n c t i o n s as l a r g e as t h o s e s t u d i e d . The meaning of t h e words s t e r i c and e l e c t r o n i c i n t h e s e d i s c u s s i o n s is somewhat ambiguous. For example, t h e l i n e a r r e l a t i o n s between parachor and t o x i c i t y found by McGowan o r t h e u s e of t h e s o l u b i l i t y parameter 6 by Mullins could b e viewed as i n d i c a t i n g a d i r e c t r e l a t i o n between t h e s i z e of t h e s u b s t i t u e n t and i t s a b i l i t y t o produce a g i v e n b i o l o g i c a l response. The a f f i n i t y of a n a p o l a r group f o r a l i p i d phase w i l l a l s o b e a f u n c t i o n
3 52
Sect. VI
-
Smi s sman, Ed.
T o p i c s in C h e m i s t r y
of i t s s i z e and, t o a lesser e x t e n t , i t s shape. Thus i t i s n o t always e a s y , even i n t h e a b s t r a c t , t o s e p a r a t e t h e b i n d i n g r o l e of hydrophobic bonding by an a p o l a r f u n c t i o n from i t s r o l e of d i s t o r t i n g a hydrophobic r e g i o n by i t s s i z e . We are a t t e m p t i n g t o u s e hydrophobic bonding as &f i n e d by p a r t i t i o n c o e f f i c i e n t s as s i m p l e h o l d i n g of t h e drug t o t h e act i v e s i t e , r e a l i z i n g t h a t o f t e n t h i s r o l e cannot be s e p a r a t e d from t h e c o n f o r m a t i o n a l change t h e a p o l a r group w i l l , i n t h e b i n d i n g p r o c e s s , produce i n an enzyme o r membrane.’ S t e r i c e f f e c t s , t h e n , a r e t h o s e due t o s i z e o r arrangement i n s p a c e of s u b s t i t u e n t s which cannot b e accounted f o r by t h e hydrophobic c o n s t a n t s l o g P and TI. These w i l l b e b o t h i n t r a - and i n t e r m o l e c u l a r i n n a t u r e . I n t h e same way, e l e c t r o n i c e f f e c t s w i l l overl a p w i t h hydrophobic bonding s i n c e t h e p o s i t i o n of e q u i l i b r i u m i n t h e d i s t r i b u t i o n of a drug between phases w i l l b e a f u n c t i o n of i t s e l e c t r o n i c s t r u c t u r e . Indeed, i t h a s been shown27 t h a t TI v a r i e s w i t h O . However, t h i s v a r i a n c e i s n o t g r e a t i f t h e s u b s t i t u e n t s a r e s e p a r a t e d by one o r more atoms. The term e l e c t r o n i c e f f e c t s means h i g h l y s p e c i f i c e f f e c t s i n g e n e r a l n o t a s s o c i a t e d w i t h t h e p a r t i t i o n i n g p r o c e s s . These would b e e f f e c t s involved i n a chemical r e a c t i o n o r charge t r a n s f e r p r o c e s s where a change i n e l e c t r o n d e n s i t y t o o small t o make a s i g n i f i c a n t d i f f e r e n c e i n l o g P could c a u s e a l a r g e change i n a r a t e o r e q u i l i b r i u m c o n s t a n t . Using t h e s e somewhat a r b i t r a r y d i v i s i o n s of s u b s t i t u e n t e f f e c t s and r e g r e s s i o n a n a l y s i s , a s t a r t can b e made i n s e p a r a t i n g t h e e f f e c t s of groups of atoms on t h e b i o l o g i c a l a c t i v i t y of a s e t of congeners. Hansch and co-workers have n o t , f o r example, a t t e m p t e d t o f a c t o r o u t hydrogen bonding. I n gene r a l t h e y have worked w i t h systems where t h i s could b e accounted f o r i n terms of o and IT. P u r c e l l e t a l . have s u g g e s t e d a way of d e a l i n g s p e c i f i c a l l y with t h i s t e r m 3 6 . I n a d d i t i o n t o many e a r l y examples1 , b i o l o g i c a l r e s p o n s e has been found t o be q u a n t i t a t i v e l y l i n e a r l y dependent on l o g P o r IT i n t h e i n h i b i t i o n of t h e H i l l r e a c t i o n 5 7 9 5 8 a c t i v i t y of p e n i c i l l i n s s 9 , t o x i c i t y of benz o i c a c i d s t o mosquito larvae28, phenol c o e f f i c i e n t s 2 8 , c h o l i n e s t e r a s e i n h i b i t o r, ~ and ~ ~ catechol-amine a c t i v i t y 6 0 .
Hernker61 w a s one of t h e f i r s t to a t t e m p t t h e q u a n t i t a t i v e c o r r e l a t i o n of b i o c h e m i c a l r e s p o n s e u s i n g b o t h p a r t i t i o n c o e f f i c i e n t s and i o n i z a t i o n c o n s t a n t s t o account f o r t h e uncoupling a c t i o n of p h e n o l s . The l i n e a r combination of TI and 0 h a s been found t o h o l d f o r s e v e r a l enzymic reaction^^^^^^ as w e l l as t h e b i n d i n g of phenols by p r o t e i n 5 5 , t h e t o x i c i t y of p h e n o l s 6 2 , t h e uncoupling a c t i o n of p h e n o l s 6 2 , and t h e r e l a t i v e sweetness of n i t r ~ a n i l i n e s ~ An ~ . i n t e r e s t i n g a p p l i c a t i o n i s t h a t of McMahon63. Equation 14 w a s formulated f o r t h e enzymic r e d u c t i o n of aromatic ketones t o alcohols.
+
+
(14) O f c o u r s e t h e most i n t e r e s t i n g and d i f f i c u l t drug s t u d i e s a r e t h o s e i n which whole organisms a r e i n v o l v e d . It h a s been p o s t u l a t e d 6 4 t h a t i n g e n e r a l , f o r t h e s e s t u d i e s one would e x p e c t a p a r a b o l i c r e l a t i o n between ~ ~ 1~5 .~ l o g 1/C and l o g P. T h i s h a s l e d t o t h e d e ~ e l o p m e n tof~ eq logVm,,
=
0.334~
1.2390
n = 10
0.824
l o g 1/C = - k ( l o g P ) 2
+
k‘logP
r = 0.89
+
pa
+
k”
(15)
Chap. 34
Drug D e s i g n
Hansch
3 53
I n t h e development of t h i s model a p r o b a b i l i s t i c view i s t a k e n f o r movement of drug from t h e exobiophase o r p o i n t of i n j e c t i o n t o t h e s i t e s of a c t i o n . It i s assumed t h a t as P-to d r u g s become more and more i s o l a t e d i n t h e water phase and e v e n t u a l l y become u n a b l e t o c r o s s l i p i d b a r r i e r s . A s Pthe reverse is true. Somewhere between P=O and P=m t h e r e w i l l b e an i d e a l v a l u e (Po) f o r a g i v e n s e t of congeners i n a g i v e n b i o l o g i c a l systein s u c h t h a t t h o s e members having t h i s v a l u e w i l l f i n d t h e s i t e s of a c t i o n v i a a random walk p r o c e s s i n t h e minimum time. T h i s assumes s t e r i c and e l e c t r o n i c (pKa, e t c . ) f a c t o r s are c o n s t a n t . I n o t h e r words, a g r e a t e r number of molecules of drug w i t h Po would r e a c h t h e s i t e s of a c t i o n i n t h e t e s t i n t e r v a l t h a n d r u g s having o t h e r P v a l u e s . I n e f f e c t , one e x p e c t s a change i n t h e mechanism of movement i n a s e t of d r u g s h a v i n g a s u f f i c i e n t s p r e a d i n P v a l u e s . The movements of t h e lower members of t h e series w i l l b e mostly determined by i n t e r a c t i o n s w i t h water, w h i l e t h o s e of t h e h i g h e r members w i l l b e determined by hydrophobic i n t e r a c t i o n s w i t h l i p i d s . Such p a r a b o l i c r e l a t i o n s may even b e found i n c l o s e d systems of t h e t y p e used i n n a r c o s i s s t u d i e s . Ferguson66 h a s s t a t e d t h a t probably i n most e x p e r i ments on n a r c o s i s a complete e q u i l i b r i u m i s n e v e r r e a c h e d i n t h e p e r i o d of exposure and t h e r e s u l t s a r e t i m e dependent. R e s u l t s w i l l b e even more t i m e dependent i n open systems such as whole animals where e l i m i n a t i o n and Such r e s u l t s can even b e exb i o t r a n s f o r m a t i o n are c o n t i n u o u s p r o c e s s e s . p e c t e d i n t i s s u e experiments o r work w i t h p a r t i a l l y p u r i f i e d enzymes. S i n c e a c t i v i t y i s u s u a l l y e x p r e s s e d a s l o g 1 / C , t h e most a c t i v e compounds M. t e s t e d a r e o f t e n i n v e r y low c o n c e n t r a t i o n , sometimes less t h a n While l o g 1/C may b e l i n e a r w i t h r e s p e c t t o l o g P a t h i g h e r c o n c e n t r a t i o n s eq 6-8 i n d i c a t e t h a t h i g h l y l i p o p h i l i c m o l e c u l e s w i l l b e v e r y t i g h t l y bound t o p r o t e i n s s o t h a t t r u e e q u i l i b r i u m i s n o t reached i n t e s t t i m e . The lower t h e t e s t c o n c e n t r a t i o n s become, t h e more l i k e l y t h e d e p a r t u r e from l i n e a r i t y through l o c a l i z a t i o n of m o l e c u l e s i n p a r t i c u l a r l y l i p o p h i l i c material. Of c o u r s e t h e r e are r e a s o n s o t h e r t h a n b i n d i n g by l i p i d s o r p r o t e i n s which might c a u s e a d e p a r t u r e from l i n e a r i t y i n t h e r e l a t i o n s h i p of l o g 1 / C and l o g P o r TI. M e t a b o l i c o r e l i m i n a t i o n r e a c t i o n s n o t s i g n i f i c a n t a t low v a l u e s of l o g P c o u l d , w i t h i n c r e a s i n g l o g P , become v e r y i m p o r t a n t . A good example of t h i s i s i n t h e metabolism of a l k y l a r y l e t h e r i n r a b b i t s 67. I n (111) when R i s e t h y l o r m e t h y l , d e a l k y l a t i o n i s t h e main r e a c t i o n . When R i s p r o p y l o r b u t y l , w - 1 hydroxy l a t i o n becomes more i m p o r t a n t . S i n c e t h e r a t e of m e t a o/ bolism of drugs may b e l i n e a r l y r e l a t e d 6 8 t o l o g P , (111) t h i s may b e a n i m p o r t a n t c o n t r i b u t i n g f a c t o r f o r t h e bCH, p a r a b o l i c dependence of a c t i v i t y on l i p o p h i l i c charOR acter. Another unknown i s t h e l i p o p h i l i c s p a c e a t t h e s i t e of a c t i o n a v a i l a b l e f o r t h e hydrophobic moiety of t h e d r u g . I f t h i s i s q u i t e l i m i t e d , t h e n a p o i n t i s soon reached where l o g 1/C and l o g P a r e no l o n g e r l i n e a r l y a s s o c i a t e d . The p r o b a b i l i s t i c n a t u r e of t h e l o g P terms i n eq 15 does a good d e a l t o i n s u r e a r e a s o n a b l e f i t of a set of d a t a as long as i n d i v i d u a l congeners i n t h e set do n o t d e p a r t r a d i c a l l y from t h e b e h a v i o r of t h o s e having similar l i p o p h i l i c c h a r a c t e r . I n p r i n c i p l e , l o s s through metabolism o r e l i m i n a t i o n i s n o t d i f f e r e n t t h a n l o s s through b i n d i n g i f t h e s e l o s s e s depend o n l y on l o g P. Good r e s u l t s have
Po.
u c ‘7’
Sect. V I - T o p i c s i n C h e m i s t r y
3 54 -
Smi s sman, Ed.
been o b t a i n e d w i t h eq 15 f o r plant-growth regulator^^^ , chloromycetin anaand c o l l e a g u e s have found a more l i n e a r dependence of l o g (Garrett69 ~ ~ ~ c h l o r o m y c e t i n a c t i v i t y under d i f f e r e n t test c o n d i t i o n s ) , t h y r o x i n e anal o g s 2 8 , phenol coef f i c i e n t s 2 8 , c a r c i n o g e n i c i t y of a r o m a t i c compounds2* , and t h e l o c a l i z a t i o n of benzeneboronic a c i d s i n b r a i n and tumor t i s s u e 7 ( ] .
A c o n s t a n t which may prove t o b e v e r y u s e f u l i n drug d e s i g n i s l o g Po ( o r no). T h i s f i g u r e can b e found by t a k i n g t h e p a r t i a l d e r i v a t i v e of eq 1 5 and s e t t i n g t h i s e q u a l t o z e r o . Once t h i s h a s been e s t a b l i s h e d f o r a set of d r u g s , i t becomes a u s e f u l bench mark from which t o s t a r t t h e des i g n of a completely new drug t o a c t on t h e same sites. For example, i t w a s found t h a t l o g Po f o r phenoxyacetic a c i d s a c t i n g as plant-growth regul a t o r s i s 2.03. Log Po f o r p h e n y l a c e t i c a c i d s a c t i n g i n t h e same system i s 2.47. I f one wished t o d e s i g n a new a c i d t o a c t i n t h i s system, one of t h e f e a t u r e s which one would d e s i g n i n t o t h e f i r s t test m o l e c u l e would b e By means of t h e a d d i t i v e - c o n s t i t u t i v e c h a r a c t e r of l o g P of about 2.2. l o g P one could d e s i g n s u c h compounds on p a p e r w i t h o u t c a r r y i n g o u t extensive partition coefficient studies. While s u i t a b l e t e c h n i q u e s t o h a n d l e s t e r i c e f /@\/OTzEt f e c t s between s u b s t r a t e and t h e material comprising (IV) t h e s i t e s of a c t i o n are a t p r e s e n t o u t of r e a c h , intramolecular s t e r i c i n t e r a c t i o n s can be handled q u a n t i t a t i v e l y , a t least i n some i n s t a n c e s u s i n g T a f t ' s E, parameter22,56. Equations 16 and 1 7 , f o r m u l a t e d from t h e work of Metcalf and Fukuto c o r r e l a t e 2 2 s u b s t i t u e n t e f f e c t s of R i n (IV) on t h e i n h i b i t i o n of c h o l i n e s t e r a s e by a l k y l p h o s p h o n i c a c i d esters.
'./
0 1
ozd
l o g K = 3.74 E, l o g K = -1.680*
+ 7.54 + 0.1511 + 4.05
E,
+
7.21
n = 13
r = 0.901
(16)
n = 13
r = 0.907
(17)
Comparison of eq 1 6 and 1 7 i n d i c a t e s t h a t n e i t h e r e l e c t r o n i c nor hydrophobic f a c t o r s p l a y a n i m p o r t a n t p a r t i n t h e i n h i b i t i o n . Thus i t a p p e a r s t h a t t h e phosphonates i n t e r a c t w i t h t h e enzyme i n such a way t h a t t h e y cannot come i n c o n t a c t w i t h a hydrophobic r e g i o n of t h e p r o t e i n . The .k r a n g e of e l e c t r o n i c f o r c e s covered by t h e R groups w a s s m a l l so t h a t u may b e more i m p o r t a n t t h a n eq 17 would i n d i c a t e . Some o v e r l a p between E, and o* c o n s t a n t s t e n d s t o o b s c u r e t h e r o l e of u*. The f a c t t h a t Es, a c o n s t a n t d e r i v e d from h y d r o l y s i s s t u d i e s under homogeneous c o n d i t i o n s , should a p p l y t o heterogeneous c a t a l y s i s i s s u r p r i s i n g and i n d i c a t e s much more u s e f o r t h i s parameter t h a n one would have had r e a s o n t o e x p e c t . Another method f o r o b t a i n i n g biochemical s u b s t i t u e n t c o n s t a n t s i s Considerable e f f o r t 7 ' a v a i l a b l e i n t h e v a r i o u s forms of chromatography. 7 3 h a s been made t o g a t h e r and A% v a l u e s f o r t h e e f f e c t of s u b s t i t u e n t s on
RF .
%
A%=%$-\
%
I n eq 18, R M ~i s c a l c u l a t e d from t h e v a l u e of a p a r e n t compound and Rp from t h a t of a d e r i v a t i v e having s u b s t i t u e n t X. ARM i s a c o n s t a n t a n a l o gous t o II and i n f a c t a c l o s e c o r r e l a t i o n e x i s t s between t h e two as i s
Hansch
Drug Design
Chap. 34
355 -
shown1 i n eq 19. = -l.l03AR,
+
0.647
r = 0.970
n = 12
(19)
l triI n measuring t h e A R M v a l u e s i n eq 1 9 , Green and M a r c i n k i e w i ~ z ~used g o 1 and d i i s o p r o p y l e t h e r i n reversed-phased, t a n k l e s s f l a t - b e d chroma~ ~ shown t h a t % v a l u e s c o r r e l a t e t h e tography. Boyce and M i l b ~ r r o whave m o l l u s c i c i d a l a c t i v i t y of a series of N - n - a l k y l t r i t y l a m i n e s assuming a p a r a b o l i c r e a c t i o n e x i s t s between l o g LD50 and %. Thus RM o r ARM v a l u e s can b e used i n eq 1 5 i n p l a c e of l o g P o r 1 ~ . C o n s i d e r a b l e e f f o r t 3 5 s75-*O h a s been made t o understand biochemic a l and pharmacological problems u s i n g quantum mechanical c a l c u l a t i o n s of e l e c t r o n d e n s i t i e s w i t h molecules. While t h i s h a s been u s e f u l i n exp l a i n i n g how a p a r t i c u l a r bond i s broken o r made75, l i n e a r r e l a t i o n s between c a l c u l a t e d e l e c t r o n d e n s i t i e s and b i o l o g i c a l a c t i v i t y are n o t a b l y l a c k i n g . An e x c e p t i o n coming from t h e work of Fukui i s i l l u s t r a t e d i n eq 20 and 2 1 which cprrelate t h e n i c o t i n e - l i k e a c t i v i t y of m e t a d e r i v a t i v e s of C6H50CH2CH2N(CH3)3 w i t h t h e s u p e r d e l o c a l i z a b i l i t y ( S o ( N 3 ) of e l e c t r o n s a t t h e o r t h o p o s i t i o n and t h e f r o n t i e r e l e c t r o n d e n s i t y (f6:;) on t h e e t h e r oxygen. logA = 13.742 So(4 logA = 30.392 f ( E ) OXY
- 10.465 - 20.924
n = 6
r = 0.994
(20)
n = 6
r = 0.949
(21)
The combination of such e l e c t r o n i c d e n s i t i e s w i t h a hydrophobic bonding c o n s t a n t does y i e l d good r e s u l t s 2 8 , 5 6 as i l l ~ s t r a t e dby~ ~eq 22 and 23. log% = 2 2 . 9 1 ~ - 42.49 log% = 0 . 2 9 ~+ 18.166.
-
33.82
n = 6
r
0.685
(22)
n = 6
r = 0.995
(23)
=
I n t h e above e q u a t i o n s Ax, from t h e work of Jacobson, r e p r e s e n t s t h e relat i v e rates of a c y l a t i o n of a r o m a t i c amines having s u b s t i t u e n t s X by means of pigeon l i v e r a c e t y l t r a n s f e r a s e . E r e p r e s e n t s t h e c a l c u l a t e d e l e c t r o n d e n s i t i e s on t h e n i t r o g e n atom made by P e r a u l t and Pullman. Equation 22 a c c o u n t s f o r o n l y 47% of t h e v a r i a n c e i n t h e d a t a w h i l e eq 23 a c c o u n t s f o r 99%. Thus i t a p p e a r s t h a t quantum m e c h a n i c a l l y o b t a i n e d e l e c t r o n d e n s i t i e s can b e e x t r e m e l y u s e f u l t o t h e m e d i c i n a l c h e m i s t . I n t h i s way t h e r e l a t i v e e l e c t r o n d e n s i t y on each atom i n t h e m o l e c u l e can b e found and through r e g r e s s i o n a n a l y s i s t h e r e l a t i v e importance of t h i s d e n s i t y a t one o r p o i n t s i n t h e m o l e c u l e c a n b e e v a l u a t e d . T h i s approach o f f e r s , i n p r i n c i p l e , a g r e a t advantage o v e r t h e u s e of u . What a r e t h e g u i d e l i n e s t h a t s u b s t i t u e n t o f f e r t h e d e s i g n e r of d r u g s ? The g r e a t s u c c e s s geneous o r g a n i c r e a c t i o n s 1 * and t h e more modest method w i t h heterogeneous b i o c h e m i c a l r e a c t i o n s t h e u s e of eq 24 and 25 as a r e a s o n a b l e working
constant analysis has t o of t h i s method i n homoachievements of t h i s would s e e m t o v a l i d a t e hypothesis.
I n eq 24 w e are assuming5' t h a t t h e u l t i m a t e l y measured b i o l o g i c a l response ( t o x i c i t y , r e s i s t a n c e t o a m e t a b o l i c p r o c e s s , E D 5 0 , e l i m i n a t i o n ,
356
Sect. VI
-
T o p i c s in C h e m i s t r y
Smi s sman, Ed.
e t c . ) i s governed by one r a t e - l i m i t i n g p r o c e s s f o r which kgR i s a r a t e o r equilibrium constant. i n eq 2 4 , mt/H r e p r e s e n t s t h a t p o r t i o n of t h e f r e e energy change which can be a t t r i b u t e d t o hydrophobic bonding, AFglect Tepr e s e n t s a n e l e c t r o n i c component, and AFzteric r e p r e s e n t s h i g h l y s p e c i f i c s p a t i a l demands of r e a c t a n t s and p r o d u c t s on t h e f r e e energy change. Of c o u r s e , were s u f f i c i e n t d a t a a v a i l a b l e , one might p r o f i t a b l y f a c t o r each of t h e terms i n eq 2 4 and 25 i n t o s e v e r a l t o r e p r e s e n t s u s p e c t e d c r i t i c a l p a r t s of a molecule. S u b s t i t u e n t e f f e c t s on l o g kgR of eq 24 are r e p r e s e n t e d i n eq 2 5 .
E q u a t i o n s 24 and 25 w e r e formulated f o r t h e c a s e where t h e drug is a t t h e s i t e of a c t i o n o r t h e s i t u a t i o n where t r u e e q u i l i b r i u m w i t h t h e exobiophase i s e s t a b l i s h e d a s envisaged by Ferguson. From t h e p r e s e n t l i m i t e d work i t would appear t h a t 'XXFi/H might be r e p r e s e n t e d by l o g P , T I ,%, ARM, B (Zahradnik15) and, under c e r t a i n cond i t i o n s p a r a c h o r . The 6xF~1ec term may be r e p r e s e n t e d u s i n g t h e v a r i o u s (5, quantum m e c h a n i c a i l y c a l c u l a t e d e l e c t r o n d e n s i t i e s o r chemiforms "'of c a l s h i f t s ' ' o b t a i n e d v i a NMR. I t should a l s o b e p o s s i b l e t o f o r m u l a t e s u i t a b l e c o n s t a n t s from I R and UV s p e c t r a . Attempts t o u s e polarographi c a l l - o b t a i n e d c o n s t a n t s do n o t seem t o b e as u s e f u l as one might expect' 5 , 8 3
.
The c a s e where s u b s t i t u e n t changes r e s u l t i n l a r g e d i f f e r e n c e s i n i o n i z a t i o n i s one of g r e a t importance s i n c e s o many d r u g s are e i t h e r weak a c i d s o r weak b a s e s . The d e g r e e of i o n i z a t i o n h a s long been r e c o n i z e d as has p l a y i n g a p a r t i n drug a c t i v i t y 8 4 . I n a c a r e f u l a n a l y s i s , F u j i t a " shown how s u b s t i t u e n t e f f e c t s on i o n i z a t i o n should be s e p a r a t e d from o t h e r e l e c t r o n i c e f f e c t s of s u b s t i t u e n t s .
It does n o t seem p o s s i b l e t o make any g e n e r a l o b s e r v a t i o n s about s u i t a b l e ways of r e p r e s e n t i n g 6XF&eric f o r t h e i n t e r a c t i o n s between a drug and i t s r e c e p t o r s . By c o n s i d e r i n g se ts of congeners i n which g r o s s s t e r i c changes a r e avoided ( e . g . , c o n s i d e r i n g D isomers s e p a r a t e l y from L i s o m e r s , e t c . ) u s e f u l c o r r e l a t i o n s can b e made. I n f a c t , where t h e twoparameter e q u a t i o n c a n be shown t o h o l d o v e r a r e a s o n a b l e r a n g e of subs t i t u e n t s , one c a n make d e d u c t i o n s about GXFEteric by c o n t i n u i n g t o i n crease t h e s i z e of X u n t i l t h e two-parameter e q u a t i o n f a i l s . I n t h i s way one c a n , t o a l i m i t e d e x t e n t , map t h e f r e e s p a c e around a r e c e p t o r s i t e . P ~ r t o g h e s e ~ ~i n- ~a n~ e, x t e n s i o n of t h e approach of Zahradnik, h a s shown t h a t l i n e a r r e l a t i o n s h i p s between d i f f e r e n t c o n g e n e r i c s e t s of a n a l g e s i c s can b e used t o make more f i r m d e c i s i o n s about whether t h e sets are a c t i n g i n t h e same three-dimensional way on t h e s a m e receptors. The t h r e e sets of congeners i n which R of V w a s h e l d c o n s t a n t ( i . e . , 1. R' = C O z E t , 2 . R' = O C O E t and 3. R' = OCOCH3) were v a r i e d by changes i n R. Least s q u a r e f i t s of sets 1 v s . 2 , 1 v s . 3 , and 3 v s . 2 gave
/\. 1
( V>
I
4.
\
t P' i
/t t
'w' A
Chap. 3 4
Hansch
Drug Design
3 57 -
s l o p e s c l o s e t o 1 w i t h good c o r r e l a t i o n c o e f f i c i e n t s . Such tests can be used t o h e l p e s t a b l i s h t h e f a c t t h a t , f o r example, R i n each series is i n By e x p l o r i n g a t h e same p h y s i c o t h e m i c a l environment on t h e r e c e p t o r s . l a r g e enough number of sets of s y s t e m a t i c a l l y v a r i e d congeners one could o b t a i n c o n s i d e r a b l e i n f o r m a t i o n about t h e geometry of t h e r e c e p t o r s i t e s . The f a c t t h a t simply changing t h e l e n g t h of R can l e a d t o a complete change i n t h e mechanism of a c t i o n ( e . g . , a g o n i s t t o a n t a g o n i s t ) h a s been thoroughly documented by AriEnsB8. A c a r e f u l case s t u d y i n which t h e ent h a l p i c and e n t r o p i c r o l e s of t h e s u b s t i t u e n t s i n t r a n s i t i o n from a g o n i s t t o a n t a g o n i s t have been c o n s i d e r e d h a s been made by B e l l e a u , T a n i and L i e B 9 . Miller and HanschZ5 have p r e s e n t e d e v i d e n c e t o show t h a t when two hydrophobic areas are p r e s e n t i n a drug and o n l y a l i m i t e d s p a c e f o r hydrophobic bonding e x i s t s i n an enzyme, t h e more hydrophobic of t h e two groups may determine t h e c o n f i g u r a t i o n of b i n d i n g . Thus s t e r i c i n t e r a c t i o n s of r e c e p t o r s i t e and s u b s t r a t e are extremely d i f f i c u l t t o e v a l u a t e . The c o n f o r m a t i o n a l p e r t u r b a t i o n s of drug on r e c e p t o r r e c e p t o r on drug w i l l t a x t o t h e l i m i t o u r a b i l i t y t o unt a n g l e t h e mechanism of drug a c t i o n f o r many y e a r s t o come. However, t h e u s e of s u b s t i t u e n t c o n s t a n t s and l a r g e computers f o r r e g r e s s i o n a n a l y s i s o f f e r s u s new hope denied workers a few y e a r s ago. References
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23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50. 51. 52. 53. 54. 55. 56. 57. 58. 59. 60.
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E. W. Deutsch and C. Hansch, N a t u r e , 2,7 5 ( 1 9 6 6 ) . C. Hansch, P r o c . I n t . Cong. Pharmacol., Sao P a u l o , 1 9 6 6 . E. M i l l e r and C. Hansch, J . Pharm. S c i . , 56, 92 ( 1 9 6 7 ) . C. C i l e n t o and M. Berenholc, Biochim. Biophys. Acta, 94, 2 7 1 ( 1 9 6 5 ) . T. F u j i t a , J . I w a s a and C. Hansch, J . Am. Chem. Soc., 86, 5175 ( 1 9 6 4 ) . C. Hansch and T. F u j i t a , J . Am. Chem. Soc., 86, 1 6 1 6 ( 1 9 6 4 ) . E . C. J o r g e n s e n and J . W. Reid, J . Med. Chem., 8, 533 ( 1 9 6 5 ) . J . Kopeck? and K. Bozek, E x p e r i e n t i a , 23, 1 2 5 ( 1 9 6 7 ) . K. BoEek, J. Kopeck?, M. Krivucova and V . Vlachova, Experimentia, 20, 667 ( 1 9 6 4 ) . J . Kopeck?, K. Bogek and D. Vlachova, Nature, 207, 9 8 1 ( 1 9 6 5 ) . S . I . M i l l e r , J . Am. Chem. SOC., 8l, 101 ( 1 9 5 9 ) . W. P . P u r c e l l , Biochim. Biophys. Acta, 105,2 0 1 ( 1 9 6 5 ) . W . P. P u r c e l l , J . Med. Chem., 9, 294 ( 1 9 6 6 ) . W . P. P u r c e l l , J . G. Beasley, R . P. Quintana and J . A. S i n g e r , J . Med. Chem. , 9, 297 ( 1 9 6 6 ) . L. P. Hamett, " P h y s i c a l Organic Chemistry,'' McGraw-Hill, New York, N.Y. , 1 9 4 0 . Y. Yukawa, Y . Tsuno and M. Sawada, B u l l . Chem. SOC. J a p . , 39, 2274 (1966). K. S . Dodgson, B. Spencer and K. W i l l i a m s , Biochem. J . , 64, 216 (1956). T. Ingami, S . S. York and A . P a t c h o r n i k , J . Am. Chem. SOC., 87, 126 (1965). M. Caplow and W. P. J e n c k s , Biochemistry, L, 883 ( 1 9 6 2 ) . R. A. D e i t r i c h , L. Hellerman and J . Wein, J . B i o l . Chem., 237, 560 (1961). R. L. Nath and H. N. Rydon, Biochem. J . , 57, 1 ( 1 9 5 4 ) . 0 . Gawron, C. J . G r e l e c k i and M. Duggan, Arch. Biochim. Biophys., 44, 455 ( 1 9 5 3 ) . R. Hanson, Acta Chem. Scand., l6, 1 5 9 3 ( 1 9 6 2 ) . R. L. Metcalf and T. R. Fukuto, J . Econ. Entomol., 55, 340 ( 1 9 6 2 ) . P . Hey, B r i t . J . Pharmacol., 1,117 ( 1 9 5 2 ) . T. C. B r u i c e and S . J . Benkovic, "Bioorganic Mechanisms," Vol. I , W.A. Benjamin Co., New York, N . Y . , 1 9 6 6 , p 1 9 . D. E. Koshland, Cold S p r i n g Harbor Symposia on Q u a n t i t a t i v e Biology, 2 7 , 473 ( 1 9 6 3 ) . J . Monod, J . Wyman and J . Changeux, J . Mol. B i o l . , l2, 8 8 ( 1 9 6 5 ) . B. B e l l e a u , J . Med. Chem. , 7 , 7 7 6 ( 1 9 6 4 ) . W. Kauzmann, Advan. P r o t e i n Chem., l 4 . , 37 ( 1 9 5 9 ) . D. J . C u r r i e , C. E. Lough, R. F. S i l v e r and H. L . Holmes, Can. J . Chem., 44, 1 0 3 5 ( 1 9 6 6 ) . P . Bracha and R. D. O'Brien, J . Econ. Entomol., 2,1255 ( 1 9 6 6 ) . C. Hansch, K. Kiehs and G . L. Lawrence, J . Am. Chem. S O C . , 87, 5770 (1965). C. Hansch, E . W . Deutsch and R. N . Smith, 3 . Am. Chem. Soc., 87, 2738 (1965) C. Hansch and E . W. Deutsch, Biochim. Biophys. Acta, 112, 3 8 1 ( 1 9 6 6 ) . K. H. Biichel, W. Draber, A . T r e b s t and E . P i s t o r i u s , Z e i t . Naturf o r s c h . , 21, 243 ( 1 9 6 6 ) . C . Hansch and E . W. Deutsch, J . Med. Chem., 8, 705 ( 1 9 6 5 ) . P . P r a t e s i , P r o c . I n t . Congress Pharmacol., Sao P a u l o , 1 9 6 6 .
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H. C. Hemker, Biochim. Biophys. A c t a , 63, 46 ( 1 9 6 2 ) . T . F u j i t a , J . Med. Chem., 2, 797 (1966). R. E . McMahon, H. W. Culp and M. M. Marsh, 149th N a t i o n a l Meeting of t h e American Chemical S o c i e t y , A t l a n t i c C i t y , N . J . , September, 1965. C. Hansch, A. R . S t e w a r d , J . Iwasa and E . W. Deutsch, Mol. Pharmacol., -1, 205 (1965). C. Hansch, R. M. Muir, T. F u j i t a , P. P. Maloney, F. G e i g e r and M. S t r e i c h , J . Am. Chem. S o c . , 85, 2817 (1963). J . Ferguson, Chem. I n c . , 1964,818. H . Yoshimura, H. T s u j i and H. Tsukamoto, Chem. Pharm. B u l l . , l4, 939 (1966). C. Hansch, A. R. Steward and J . I w a s a , J . Med. Chem., 8, 868 (1965). E . R. Garrett, 0. K. Wright, G. H. Miller and K. L . Smith, J . Med. Chem., 2, 203 (1966). C. Hansch, A. R. Steward and J . Iwasa, Mol. Pharmacol., 1,8 7 (1965). J. Green and S. Marcinkiewicz, J . Chromatog., 10,389 (1963). L. S. Bark and R. J . T. Graham, T a l a n t a , 13,1281 (1966). L. S. Bark and R. J . T. Graham, J . Chromatog., 23, 417 (1966). C. B. C. Boyce and B. V. Milborrow, N a t u r e , 208, 537 (1965). B. Pullman and A. Pullman, "Quantum B i o c h e m i s t r y , " I n t e r s c i e n c e P u b l i s h e r s , New York, N . Y . , 1963. B. Pullman, " E l e c t r o n i c A s p e c t s of B i o c h e m i s t r y ,I' Academic P r e s s , 1964, p 559. K. Fukui, K. Morokuma, C. Nagata and A. Imamura, B u l l . Chem. SOC. J a p a n , 34, 1224 (1961). K. Fukui, C. Nagata and A. Imamura, S c i e n c e , 132, 87 (1960). A. Szent-Gyorgyi, " I n t r o d u c t i o n t o a Submolecular B i o l o g y , " Academic P r e s s , New York, N.Y., 1960. F. Yoneda and Y . N i t t a , Chem. Pharm. B u l l . , l3, 574 ( 1 9 6 5 ) . R. W. T a f t , E . P r i c e , I. R. Fox, I. C. Lewis, K. K. Anderson and G. T. Davis, J . Am. Chem. S o c . , 85, 3146 (1963). E. R. Garrett and A. G . Cosimano, J . Pharm. S c i . , 55, 702 (1966). L. G . P a l e g and R. Muir, P l a n t P h y s i o l . , 27, 285 (1952). A. A l b e r t , "Selective T o x i c i t y , " J o h n Wiley & Sons, New York, N.Y., 3 r d Ed., 1965, p 178. P. S. P o r t o g h e s e , J . Pharm. S c i . , 54, 1079 ( 1 9 6 5 ) . P. S. P o r t o g h e s e and T. N . R i l e y , J . Pharm. S c i . , 54, 1 8 3 1 (1965). P. S . P o r t o g h e s e , J . Med. Chem., 8, 609 (1965). E. J . AriEns, "Molecular Pharmacology," Vol. 1, Sec. 11, Academic P r e s s , N e w York, N . Y . , 1964. B. B e l l e a u , H. T a n i and F. L i e , J . Am. Chem. Soc., 87, 2283 ( 1 9 6 5 ) .
S U B J E C T INDEX
A d r e n a l s t e r o i d o g e n e s i s , 263 AMP, cyclic, 286 Analgetics, 33 A n e s t h e t i c s , G e n e r a l , 24 Angina P e c t o r i s , 6 9 Ano r exigen s, 44 Antiallergy agents, 83 Antianginals, 69 Anti-anxiety a g e n t s , 1 A n t i b a c t e r i a l s , synthetic, 112 Antibiotics, 102 Anticonvulsants, 24 A n t i d e p r e s s a n t s , 11 Antidiabetics, 176 Antifungals, 157 A n t i h y p e r t e n s i v e s , 48 A n t i i n f l a m m a t o r y a g e n t s , nons t e r o i d a l , 217 A n t i n e o p l a s t i c s , 166 A n t i p a r a s i t i c s , a n i m a l , 147 A n t i p a r a s i t i c s , h u m a n , 131 Antip s y c h o t i c s, 1 A n t i r a d i a t i o n a g e n t s , 330 A n t i v i r a l s , 122 A t h e r o s c l e r o s i s , 187
B i o p h a r m a c e u t i c s, 340 C e l l M e t a b o l i s m , regulation, 286 D i u r e t i c s , 59 D r u g Design, s u b s t i t u e n t cons t a n t s in, 347 D r u g - R e c e p t o r I n t e r a c t i o n s , 227 Drug Sensitization, 256 D r u g s , f a t e and d i s t r i b u t i o n , 237 Gastrointestinal agents, 9 1 Hallucinogens, 11 5 - H y d r o x y t r y p t a m i n e , 27 3 Hypnotics, 24 M u s c l e R e l a x a n t s , 24 N u c l e o s i d e s , 304 Nucleotides, 304 P e p t i d e s , synthetic, 296 P h a r m a c e u t i c s , 340 Pulmonary agents, 83 R e a c t i o n s i n Medicinal C h e m i s t r y , 321 Reproduction, 199 S e d a t i v e s , 24 S t e r o i d H o r m o n e s , 208 S t e r o i d s , 31 2 S t i m u l a n t s , 11 Substituent c o n s t a n t s i n d r u g design, 347
COMPOUND NAME INDEX
36 1 -
4 8 / 8 0 , 269 6 - A m i n o n i c o t i n a m i d e , 3 34 Acetaminophen, 39, 6 6 2-Amino- I -pentanethiol, 331 A c e t a z o l a m i d e , 117, 235 2-Amino- 1 - p h e n y l e t h a n e t h i o l s , 331 Acetohexamide, 182 p - Aminop r opiophenone, 3 34 Acetophenetidine, 39, 241 p - A m i n o s a l i c y l i c a c i d , 112 Acetylcholine, 227, 233 2-Aminothiazoline s a l t s , 332 N-Acetylcysteine, 8 5 A m i t r i p t y l i n e , 16, 95 N - A c e t y l g l u c o s a m i n e , 235 A m p h e t a m i n e , 13, 17, 44, 45, 46 Acetylenic c a r b a m a t e s , 172 d - A m p h e t a m i n e , 44, 45, 46, 240 N - A c etyl- N- phenylhydroxylamine, p- ethyl-, 45 Amphetamine, 240 Amphetamine, p- trifluoromethyl-, A c e t y l s p i r a m y c i n , 108 45 10 -Acetylyohimbane, 3 A m p h o t e r i c i n B, 157 ACTH, 264, 265, 268, 269 A m p i c i l l i n , 10 3 Actinomycin D, 169, 265, 334 A m p r o l i u m , 153 Actomol, 17 A m y t a l , 268 A d a m a n t a n e c a r b o x a m i d e , N - m e t h y l , A n d r o s t e n e d i o n e , 267 o c t a c h l o r o c h l o r i n a t i o n prod. , Angiotensin, 93, 265 123 p-Anilinophenylacetic a c i d , 220 Adenosine monophosphate, 3 ' , 5' 4-Anilino- 5 - p y r i m i d i n y l c a r b o x y l i c c y c l i c , 60, 61, 66, 94, 177a c i d s , 221 179, 181, 286-293 A n i s o t r o p i n e m e t h y l b r o m i d e , 98 A n t i d i u r e t i c h o r m o n e , 65, 93 Adenosine monophosphate, 3 ' , 5 ' c y c l i c , d i b u t y r y l , 287, 290 A n t i m y c i n A, 268 A d r e n o c h r o m e s e m i c a r b a z o n e , 249 A r a b i n o s y l c y t o s i n e , 167 AHR 1209, 26 A r a b i n o s y l f l u o r o c y t o s i n e , 167 A l d o s t e r o n e , 234 A r g i n i n e , 177 Allopurinol, 250 A s p a r a g i n a s e , 170-171 A m a n t a d i n e h y d r o c h l o r i d e , 122, 1 2 3 A s p i r i n , 37, 38, 40, 96 Ambunol, 333 AY-9944, 189 Amiloride hydrochloride, 63 A z a t h i o p r ene, 98 2 - A m i n o a l k y l m e r c a p t o imi da z oline s , A z a t h y m i dine, 12 5 332 6 - A z a u r i d i n e , 125 2 - A m i n o e t h a n e s e l e n i c a c i d , 33 1 Ba-30803, 11 2-Aminoethylphosphoric a c i d , 333 Ba-31531, 84 Aminoglut e t h i m i d e , 26 6, 26 7 B a y e r 1443, 19 3 -Amino - 4 - m e r c a p t o - 1 - butanol, B a y e r 1500, 60 331 Benfurodil, 75 2-Amino- 3 - m e t h y l - 1-butanethiol, 0 - Benzamidophenoxyac e t i c a c i d s , 331 221 S- 2- Amino - 2 - m e t h y l p r o p y l p h o s 0 - B e n z a m i d o p h e n y l a c e t i c a c i d s , 22 1 p h o r o t h i o i c a c i d , 33 1 Benzilylcholine, 233 S- 2- Amino - 2 - m e t h y l p r o p y l t h i o B e n z i m i d a z o l e s , 94 s u l f u r i c a c i d , 331 B e n z o i s o t h i a z o l e , 94
362 -
COMPOUND NAME INDEX
Benzomorphans, 34 B enzphetamine, 44 Benzphetamine analogs, 44 Benzquinamide, 3 Benzydamine, 39 B enz ylimi dazol e s , 2 6 7 Bepzyl methyl sulfone, 223 Benzyl methyl sulfoxide, 223 B enzylpenicillin, 10 3 Biguanides, 182 3 -Biphenyl- 6 - ketopiperidine, 267 3 -Biphenylpiperidine, 26 7 4 - Biphenyl yl- 3- hydr oxybuty ri c a c i d , 220 2, 2'-Bipyridine, 94 Bis-(4-acetoxyphenyl) cyclohexylidenemethane, 251 Bi solvon@, 8 6 Bradykinin, 93 Brinaldix, 6 1 Brobenzoxalidine, 160 B r o c r e s i n e , 87 N-(2-Bromoethy1)-N-ethyl-N- 1naphthylmethylamine, 23 1 Broxyquinoline, 164 BUdR, 125 Buquinolate, 153- 154 Busulfan, 98 1, 4-Butanediol, 29 p-n-Butoxyphenylac ethydroxamic acid, 220, 241 1-Butylbiguanide, 240 t - Butylmethoxamine, 7 8 y-Butyrolactone, 29 Buxenine-G, 3 16 Buxp siine, 3 16 BW 58-271 (rolodine), 26 Caffeine, 1 Calcium pantothenate, 333 Candicidin, 158 Capreomycin, 108 Caprochlorone, 123 Carbochromene, 72, 74, 75 C a t a p r e san@, 48 CB 2487, 27
-
Cephaloglycin, 10 5 Cephaloridine, 104, 105 Cephalosporin C, 102 Cephalosporin P l y 314 Cephalothin, 102, 104, 105 Chloral hydrate, 333 Chloramphenicol, 112, 117, 241 Chloramphenicol analogs, 108 Chloridazepoxide, 1, 2, 5, 7, 95 Chlormadinone a c e t a t e , 199 C h l o r m e r o d r i n , 59 1-p -- Chlor obenzylidenyl- 5- methoxy 2-methyl- 3-indeneacetic acid, c i s - , 219 ( t)- 3- Chloro - 4- cyclohexyl -a- m ethyl phenylacetic acid, 220 7-Chlorodeoxylincomycin, 106 N-2- Chloroethyl- N-methyl- 2- amino ethyl benzilate, 7, 233 pChloromercuribenzoic acid, 94, 268 p-Chlorophenylalanine, 3, 24 1-(4-Chlorophenyl)-4-{ 2- [3-(2pyridy1)acryloxy]ethyl] p i p e r a z i n e , 223 a - (p- Chloropheny1)-a-( 2-pyridyl) glutarimide, 267 Chloroquine,' 131, 132, 133, 217, 249 7-Chlorotheophylline, 73 Chlorothiazide, 6 1 6- Chlorothymine, 334 Chlorphenesin c a r b a m a t e , 27 Chlorphentermine, 44, 46 Chlorphenvinphos, 242 Chlorpromazine, 1, 2, 3, 4, 5, 7, 13, 16, 19, 95, 252 Chlorpropamide, 178 Cholecystokinin, 96, 97 Cholesterol, 312 Cholestyramine, 191 CI-564, 135 CI-578, 141 CI-581, 28 Cinerubin, 168
363 -
COMPOUND NAME INDEX Clamoxyquin pamoate, 137, 138 Cloferex, 44, 46 Clofibrate, 189, 190, 193 Clomiphene, 267 Clomiphene c i t r a t e , 204 Clopamide, 6 1 Clopenthixol, 4, 251 Clothiapine, 4 Cloxacillin, 10 3 CN- 55, 945-27, 201 Codeine, 37 Complamine, 333 Conessine, 312, 315 Cortexone, 214 Corticotrophins, 269 Cortisone, 193 5-Crotyl- 5-ethylbarbituric a c i d , 245 Crustecdysone, 313 CUdR, 125 Cyanocobalt-chlorophyllin, 3 33 Cyanotrimethylandrostenalone, 267 Cyclazocine, 37, 38 Cycloguanil pamoate, 134, 135 Cycloheximide, 159, 169- 170, 265 Cyclohexanol succinate, 334 9- Cyclopentyl- 6-mercaptopurine, 125 Cyclophosphamide, 66, 222 Cycloserine, 113 Cyprolidol, 11, 12 Cy st eamine- S- pho sphat e, 334 Cysteamine-S- sulfate, 331 Dichloroisoproterenol, 77, 94, 268 Cysteine, N-dithiocarbamate, Strithiocarbonate, 332 Cysteine thiosulfate, 334 Cytarabine, 125 DADDS, 135 Dapsone ( a l s o DDS), 132, 133, 135, 242 Dapsone sulfoxide, 242 Daunomycin, 168 DDS, s e e dapsone Debrisoquin, 52
Decalones, 247 Decamethonium, 23 3 Dehydro epiandro s t e r one, 26 7 8 -Dehydro- 16a-methylprednisolone, 20 8 Dehydrosanol ( a l s o Diu 60), 62 Demethylchlortetracycline, 106 Demi s sidine, 3 15 2-Deoxyglucose, 92, 177 Desipramine, 1 3 Desmethylimipramine, 13, 252 Dexamethasone, 265 Dextromoramide, 97 N, N - Di- (m-aminophenyl)butylethylmalonamide, 223 Diazepam, 5, 6, 7, 333 Diazoxide, 53, 177, 178 Dibenamine, 231, 233 5H-Dibenzo [a, dlcycloheptene- 5carboxamide, 252 2, 6-Dichlorobenzonitrile, 242 2, 6-Dichlorothiobenzamide, 242 Dicloxacillin, 10 3 2 Diethylaminoethyl- 4-me thylp i p e r a z i n e - 1-carboxylate, 126 Diethyl dithiocarbamate, 268, 335 Digitoxigenin, 31 4 Dihydroaldrin, 247 Dihydroergotamine, 178, 268 Dihydromorphine, 36 Dihydroxyprogesterone acetophenide, 199 Dimethacrin, 11 3,4-Dimethoxyphenethylamine, 19 2 - Dimethylb e n z a n t h r a cene, 267 N, N-Dimethyl-2-chloro-2-phenethylamine, 233 Dime thyli sopr opylmethoxamine, 78 6a, 18-Dimethylnorethiqterone, 210 Dimethylsulfone, 223, 239 Dimethylsulfoxide, 125, 223, 239 N, N-Dimethyl-2-(m-tolylazo)aniline, 268 (Dimethyltriazeno)imidazolecarboxa m i d e , 172
-
-
-
364 -
COMPOUND NAME INDEX
Dinit rophenol, 268 Diphenidol, 98 Diphenoxylate, 97 Diphenylhydantoin, 267 Dipyridamole, 73 D i s u l f i r a m , 335 5, 5'-Dithiobis-(Z-nitrobenzoic a c i d ) , 219 Ditran, 19 Diu 60, see D e h y d r o s a n o l DMPEA, 19 D o x a p r a m , 30 Doxycycline, 10 6 Doxylamine, 26 Dymanthine, 141 E c d y s o n e , 213, 313 E c d y s t e r o n e , 21 3, 31 3 E n c y p r a t e , s e e MO- 1255 E p h e d r i n e , 45 E p i n e p h r i n e , 94, 178, 181, 227, 232, 268 Equilin, 313 E r g o t a m i n e , 19, 20 E s t r a d i o l , 234, 267 E s t r a d i o l d i p r o p i o n a t e , 21 3 E s t r a d i o l e n a n t h a t e , 199 E s t r o n e , 267 E t h a c r y n i c a c i d , 60 E t h a m b u t o l , 113, 114, 118 E t h i o n a m i d e , 113, 114, 244 E t h i o n a m i d e sulfoxide, 244 E t h o p a b a t e , 153, 243 2-Ethylhexyl s u l f a t e , 240 N - E t h y l m a l e i m i d e , 94, 268 Etrafonm, 16 F e n f l u r a m i n e , 46 F e r r i c yanide, 2 68 F l u f e n a m i c a c i d , 218 F l u o r o d e o x y u r i d i n e , 167 1 - ( 4 - F l u o r o p h e n y l ) - 1 -phenyl-2p r opynyl- N- c y clohexylc a r b a m a t e , 126 F o r m a m i d i n e a c e t a t e , 268 FR33, 5 Fr enolicin, 160
N1 - F u r f u r y l b i g u a n i d e , 127 F u r 0 s e m i d e , 60 F u r t e r e n e , 62 F u s i d i c a c i d , 314 Gamf exine, 18 G a s t r i n , 91 G a s t r i n 11, 92 G a s t r i n p e n t a p e p t i d e , 91, 97 G e n t a m i c i n , 107 Glaphenin, 39 Glucagon, 93, 97, 177, 178, 181 G l u t e t h i m i d e d e r i v a t i v e s , 266, 267 Glycerylaminophenaquine, 249 Glycopyrrolate, 95 G r i s e o f u l v i n , 159 G r o w t h h o r m o n e , 177, 178, 181 G u a n o c l o r , 52 Guanoxan, 2 50 Hadacidin, 333 H a l i d o r , 95 H a l o p e r i d o l , 1, 2, 5 1 - H a l o p r o p a n e s , 239 Halothane, 28 Haloxon, 151 H a m y c i n , 158 H e m a t o p o r p h y r i n , 333 Hetacillin, 103 H e x a d i m e t h r i n e b r o m i d e , 267 Hexamethonium, 96 Hexobendine, 7 5 1 -Hexyl- 3, 7-dimethylxanthine, 2 50 H i s t a m i n e , 227, 234, 269 A- Homot e s t o r enone, 3 12 Hpt-909, 87 Hycanthone, 139 H y d r o c h l o r o t h i a z i d e , 53 H y d r o c o r t i s o n e , 217 H y d r oxyb e n z y l b e n z i m i dazol e , 1 2 2 y-Hydroxybutyric a c i d , 29, 333 Hydroxychloroquine, 249 N6-(2-Hydroxyethyl)-adenine, 125 2 - H y d r o x y i m i p r a m i n e , 16 7 - ( H y d r o x y m e t h y l )- m e t h y l b e n z a n t h r a c e n e , 267
COMPOUND NAME INDEX 7 - Hydroxy- 1 - m e t h y l q u i n o l i n i u m iodide, 233 Hydroxyquinolines, 160 5- Hydroxytryptophan, 96 H y d r o x y u r e a , 126, 172 H y o s c i n e , 233 Hypoglycin A, 239 IBD-78, 4 Ibuf e n a c , 2 18 ICI 4 3 , 8 2 3 , 222 ICI 4 6 , 4 7 4 , 201 ICI 4 7 , 7 7 6 , 222 ICI 50, 123, 91, 92 Idoxuridine, 12 5 Ildamen, 75 Imidoline, 7 I m i p r a m i n e , 12, 13, 14, 19, 95, 252, 333 Indane- 1, 2-diol, 246 Indomethacin, 218 Indoxole, 218, 222 I n n o v a r B , 30 INPEA, 78 Insidon, 333 Insulin, 92, 176, 227, 230 Iodinin, 108 Iodoac e t a m i d e , 94 I o d o a c e t i c a c i d , 268 I p r o v e r a t r i l , 72, 74, 7 5 I s o c o n e s s i n e , 31 5 Isoindolinium salts, 333 I s o m e t h a d o n e , 35 I s o n i a z i d , 117, 118 I s o p r o t e r e n o l , 94, 96, 178, 333 Isoquinazepon, 6 I s o s o r b i d e d i n i t r a t e , 73 I s o t h i a z o l e t h i o s e m i c a r b a z o n e , 124 I s t o n i l , 11 IUdR, s e e I d o x u r i d i n e K a n a m y c i n , 108, 112 K a s u g a m y c i n , 108 K u r c h i p h y l l i n e , 3 16 L e u c i n e , 177 Leucodelphinidine, 3 3 3 L i l l y 5164, 16
365
L i n c o m y c i n , 10 6 L i n o l e x a m i d e , 192 L i t h i u m ion, 7 LL-195, 7 LSD, 19 LU 3-010, 11 L u 3-057aY 11 Lucanthone, 139 L u c e n s o m y c i n , 158 LW3170, 4 M a g n e s i u m p e m o l i n e , 18 M a l e t h e m e r , 98 Mannoheptulose, 177, 180 M a r i j u a n a , 19 M & B 10, 755, 152 M e b a n a z i n e , 17 M e b u t a m a t e , 53 M e c l o f e n a m i c a c i d , 221 M e d r o x y p r o g e s t e r o n e a c e t a t e , 199 M e f e n a m i c a c i d , 221 M e f r u s i d e , 60 M e l i t r a c e n , 11 Menadione, 334 M e p e r i d i n e , 97 M e p r o b a m a t e , 1, 5 Meprophendiol, 243 M e r a l l u r i d e , 59 2 - M e r c a p t o e t h y l a m i n e d e r i v s . , 331 6 - M e r c a p t o p u r i n e , 98 M e r s a l y l , 60 M e s c a l i n e , 19, 20, 243 M e t a p r o t e r enol, 8 3 Metaraminol, 13 Metaxalone, 243 M e t h a c y c l i n e , 106 Methadone, 35 Methamphetamine derivs. , 45 Methaqualone, 25, 250 Methionine sulfoximine, 7 M e t h i s a z o n e , 124 M e t h i t u r a l , 245 M e t h o t r e x a t e , 251 M e t h o t r im e p r a z i n e , 3 6 M e t h o x a m i n e , 3 33 Methoxyindoles, 248
366 -
COMPOUND NAME INDEX
5-Methoxytryptophol, 248 Neuroleptanalgesics, 30 Methylaminodeoxyuride, 125 Nicotinic acid, 189, 192 Methylcholanthrene, 268 Nicotinyl alcohol, s e e RoniacolB a-Methyldopa, 53 Niridazole, 136, 137, 138 a-Methyldopamine, 13 Nitrazepam, 25 16-Methylenechlormadinone, 210 Nitrodan@, 151, 152 Methylrnercaptopurine riboside, 166 Nitrofurans, 113, 116, 117, 118 N-Methyl- 3-pyrrolidylphenylcyclo- Nitroglycerin, 71, 72, 73, 79 pentylglycolate, 19 N i t r o s o u r e a d e r i v a t i v e s , 171 18-Methylnorethi s t e r o n e , 21 0 Nogalamycin, 168 18-Methyl- 1 9 - n o r p r o g e s t e r o n e , 210 Norepinephrine, 12, 178, 232, 268 Methyl salicylate, 96 Norethandrolone, 267 N-Methyl- y- tocopheramine, 249 N o r e t h y r o d r e l , 267 a-Methyltyramine, 13 Normetanephrine, 13 a-Methyltyrosine, 3, 5, 46, 53 Nortriptyline, 4, 95 Methyprylon, 27, 245 Novastat@, 154 Meticlorpindol, 154 NSD-1055, 87 Metronidazole, 136, 137, 246 Nystatin, 157 Metyrapone, 266 Oligomycin, 268 Minocycline, 10 6 Ophiobolo sin, 160 Mithramycin, 168 Opipramol, 95 MJ 1987, 8 3 Oripavines, 33 MJ 1988, 8 3 Oxacillin, 10 3 MJ 1992, 8 3 1, 3,4-Oxadiazolium s a l t s , 332 Oxazepam, 2, 5 MJ 1999, 77 MK-741, 4 Oxyclozanide, 152 MO- 1255 ( e n c y p r a t e ) , 16 Oxye thy1theophylline, 7 4 Morphinans, 33 Oxypertine, 7 Morphine, 33, 36, 37, 96, 97 Oxytetracycline, 106 NADP, 264, 265 Oxytocin, 93, 227 NADPH, 263, 264 Pactamycin, 169 Nafiverine, 97 P a p a v e r i n e , 71, 96, 97 Nalidixic acid, 112, 117 P a r g y l i n e , 17, 52 Nalorphine, 36, 40, 333 P a r o m o m y c i n , 135, 142 Naloxone, 38 Pasaden, 4 Namoxyrate, 220 Pemoline, 18 Naphthoquinones, 267 Penamecillin, 104 Naphthypramide, 220, 247 Penicillamine, 217 Naphthyridines, 112, 113 P e n i c i l l i n aldehydes, 104 Necrotoxin, 160 P e n i c i l l i n s , 112 Nembutal, 3 3 3 P e n o t r a n e , 161 Neoconessine, 31 5 P e n t a e r y t h r i t o l t e t r a n i t r a t e , 73 Neomycin, 112, 191 Pentazocine, 37 Neospiramycin, 108 Pentobarbital, 44 Neostigmine, 96 P e r p h e n a z i n e , 16
COMPOUND NAME INDEX Peyote, 19 Phagicin, 126 Phenazinium s a l t s , 333 Phenformin, 182, 190 Phenindione, 95 Pheniprazine, 13, 16 P h enm e t r a z i n e , 4 5 Phenobarbital, 2 3-Phenothiazineac etic a c i d s , 2 2 1 Phenoxybenzamine, 94, 231, 232 P h e n t e r m i n e , 46 Phentolamine, 94, 178 Phenygam, 7 1-Phenylazo- 2-naphthol, 244 Phenylbutazone, 218, 268 1-Phenylpiperazine, 46 Phleomycin, 169 6-Pho sphogluconolactone, 333 Phthalanilides, 333 P i l o c a r p i n e , 96 P i m a r i c i n , 157 P i m e t i n e , 86 Pinoxepine, 4 P i r i b e n z i l , 95, 97 Poldine, 95 Polymyxins, 114 Polynoxylin, 16 1 P oly vinylpy r r ol'idone , 126 P o n a s t e r o n e A, 213 Prazepam, 5 P r e m a r i n B , 189 P r e n y l a m i n e , 2, 3, 71, 74 P r o c a i n e a m i d e s , 332 P r o c a r b a z i n e , 17 1 Prodilidine, 36 P r o g e s t e r o n e , 56 Pronethalol, 77 Propanidid, 29 Propanolol, 53, 78, 79, 178, 192, 247 P r o s t a g l a n d i n E l , 192, 193 P r o t r i p t y l i n e , 12 Psilocybin, 19 Puromycin, 265 Pyramidon, 39
367
P y r a n t e l , 141, 142 P y r a n t e l t a r t r a t e , 148 Pyridinolcarbamate, 7 5 P y r i m e t h a m i n e , 131, 132, 133, 134 P y r i m i d i n e s , 95 P y r r o l n i t r i n , 160 P y r v i n i u m pamoate, 141 Quindonium b r o m i d e , 252 Quinoxaline di-N-oxides, 115 R e s e r p i n e , 2, 3, 5, 12 Riboflavine, 333 Rifaldazine, 107 Rifamycin SV, 107 Rifazine, 107 Rimantadine hydrochloride, 123 RO 1-8307, 267 RO 4-4602, 3 RO 4-5282, 45 RO 5-6901, 25 Roletamide, 26 Rolodine, s e e B W 58-271 RoniacolB (nicotinyl alcohol), 191 Rufochromomycin, 160 Salicylamide, 96 Salicylic acid, 96 Samandenone, 3 16 SC-16100, 65 SC-16102, 65 S e c r e t i n , 93 Serotonin, 227, 234, 334, 335 S K & F 6678, 45 S K & F 12185, 266 S K & F 14336, 4 Sodium salicylate, 38, 39 Soladulcidine, 3 14 Solasodine, 314 Spiramycin, 108 Sporaviridin, 160 SQ 10,648, 87 Squal ene, 3 12 Stilbestrol, 244 Streptomycin, 112 Su-8000, 268 SU-9055, 268 SU-10603, 268
368 -
COMPOUND NAME INDEX
SU-14074, 64 Sulclamide, 61 Sulfadimethoxine, 11 5, 132, 246 Sulfamethoxypyridazine, 11 5, 132 Sulfanilamides, 114, 115, 118, 332 Sulfapyrazinemethoxine, 132 Sulfapyrimidines, 11 5, 118 Sulfa symazine, 114, 118 Sulfonylureas, 177, 180, 182 Sulforthomidine, 132 T a r a c t a n , 333 T e s t o s t e r o n e , 267 Tetrabenazine, 2, 3, 13, 251 T e t r a c y c l i n e s , 112, 117, 333 T e t r a m i s o l e , 141, 149, 150 Theophylline, 178, 265 Thiabendazole, 140, 141, 150, 160 Thiazothienol, 246 6- Thioguanosine, 98 Thioridazine, 2 Thiothixene, 4 D-Thyroxine, 189, 193 TMB-4, 245 a- Tocopheramine, 249 Tolazamide, 182 Tolazoline, 94 Tolbutamide, 182, 242 Tolnaftate, 160 Tomatidine, 314 Tranylcypromine, 17 Trausabun, 11 T r i a m t e r e n e , 53, 61, 62 TriavilB, 16 s- T r i a z i n e s , aminoalkoxydiamino-, 46 s- T r i a z o l e s , 332 Trichlorofon, 140 Trichomycin, 158 8- Trifluoromethylphenothiazine- 1 carboxylic acid, 221 Trifluperidol, 190 17p Trimethylsiloxytestosterone, 21 1 T r i m e t o z i n e , 26 Trioxazine, 26
-
-
T r i p a r a n o l , 189 Triperidol, 5 Tropenzilene, 95 Tryptizol, 333 Tybamate, 5 Tyramine, 241, 333 U-16,178F, 45 U-23,807A, 18 U r a c i l methyl sulfone, 125 Urea, 8 5 Uridine monophosphate, 333 Variotin, 160 V a s o p r e s s i n , 268, 269 Vinblastine, 170 Vinglycinate sulfate, 170 Vinleurosine, 170 Viractin, 126 Vitamin K5, 333 WIN 1344, 18 Wy-5256, 62 X-5079C, 159 Xylopinine, 3 Xanthine oxidase inhibitors, 126 Zearalenone, 204
4 8 5 C 6 D 7
~a
F 9 G O
H 1 1 2 1 3
