TECHNICAL FIELD 
This invention relates to novel 1,4-dihydropyridine compounds, and more 
particularly to 1,4-dihydropyridine compounds having a substituted or 
unsubstituted-carbamoylmethyl group attached to the 2-position of the 
dihydropyridine ring. These compounds are useful as antagonists of 
bradykinin, and are thus useful in the treatment of inflammation, 
cardiovascular disease, pain, common cold, allergies, asthma, 
pancreatitis, burns, virus infection, head injury, multiple trauma or the 
like in mammalia, especially humans. The present invention also relates to 
a pharmaceutical composition useful in the treatment of the above clinical 
conditions, which comprises the 1,4-dihydropyridine compound of the 
invention and a pharmaceutically acceptable carrier. 
BACKGROUND ART 
Bradykinin ("BK") is generated under normal conditions in mammalia by the 
action of various plasma enzymes such as kallikrein on high molecular 
weight kininogens. It is widely distributed in mammals, as are its two 
receptor subtypes, B.sub.1 and B.sub.2. The actions of BK at the B.sub.1 
receptor include mainly contraction of arterial and venous preparations, 
although it can cause relaxation of peripheral resistance vessels as well. 
Many of the more important functions of BK, such as increases in vascular 
permeability, pain, and vasodilatation, however, are mediated by the 
B.sub.2 receptor. These effects at the B.sub.2 receptor are believed to be 
responsible for BK's role in numerous diseases, such as inflammation, 
cardiovascular disease, pain, and the common cold. Hence antagonists at 
the B.sub.2 receptor should find considerable therapeutic applications. 
Most of the efforts in this area thus far have been directed at peptidic 
analogues of the BK structure, some of which have been studied as 
analgesics and antiinflammatory agents. 
It would be desirable if there were provided a non-peptide antagonist of 
the B.sub.2 receptor, having a good B.sub.2 antagonistic activity and a 
good metabolic stability. 
BRIEF DISCLOSURE OF THE INVENTION 
The present invention provides a compound of the formula: 
##STR2## 
and its pharmaceutically acceptable salts, wherein A.sup.1 and A.sup.2 are 
each halo or H; X.sup.1 is CH.sub.2, CO, SO or SO.sub.2 ; X.sup.2 is a 
direct bond CH.sub.2 or CO; Y is piperazinyl-(CH.sub.2).sub.n --, 
2,3,4,5,6,7-hexahydro-1H-1,4-diazepinyl-(CH.sub.2).sub.n -- or-- 
N(R.sup.5)--(CH.sub.2).sub.n -- wherein R.sup.5 is H or C.sub.1-4 alkyl, 
and n is 0, 1, 2, 3, or 4; R.sup.1 is selected from the following: 
(a) N-morpholino-C.sub.1-4 alkylphenyl, C.sub.1-4 alkoxycarbonyl, C.sub.2-5 
acyl, 4,5-dihydroimidazolyl, formamidino, guanidino or 
dihydroimidazolylamino, optionally substituted with one or two 
substituents selected from C.sub.1-4 alkyl, hydroxy and amino; 
(b) hydrogen, C.sub.1-4 alkyl optionally substituted with one or two 
substituents selected from hydroxy, amino, C.sub.1-4 alkylamino, 
di-C.sub.1-4 alkylamino, pyridyl, carbamoyl, pyrrolidinocarbonyl, 
propylaminocarbonyl, piperidinocarbonyl or morpholinocarbonyl; 
(c) piperidinyl optionally substituted on the nitrogen atom with C.sub.1-4 
alkyl or C.sub.1-4 alkoxycarbonyl; 
(d) C.sub.5-14 cycloalkyl, bicycloalkyl or tricycloalkyl, optionally 
substituted with one or two substituents selected from oxo, hydroxy, 
amino, guanidino, C.sub.1-4 alkylamino, di-C.sub.1-4 alkylamino, 
methoxybenzamido or morpholino; 
(e) C.sub.7-14 azacyclo-, azabicyclo- or azatricyclo alkyl, in which the 
nitrogen atom optionally has a substituent selected from C.sub.1-4 alkyl, 
formamidino, dihydroimidazolyl, benzyl optionally substituted with one or 
two substituents selected from halo and trihalo C.sub.1-4 alkyl, C.sub.1-4 
alkyloxycarbonyl optionally substituted with one or two halogen atoms and 
C.sub.2-5 acyl; and 
(f) C.sub.7-10 bicycloalkenyl, benzo C.sub.5-7 cycloalkyl or heterocyclic; 
as hereinafter defined with proviso that when Y is piperazinyl, (i) at 
least one of A.sup.1 and A.sup.2 is H; X.sup.2 is CH.sub.2 or R.sup.1 is a 
group selected from group (a); (ii) at least one of A.sup.1 and A.sup.2 is 
H and X.sup.2 is CH.sup.2, (iii) at least one of A.sup.1 and A.sup.2 is H 
and R.sup.1 is a group selected from (a); (iv) X is CH.sup.2 and R.sup.1 
is a group selected from (a); or (v) at least one of A.sup.1 and A.sup.2 
is H, X.sup.2 is CH.sup.2 and R.sup.1 is a group selected from (a); 
R.sup.2 is hydrogen, C.sub.1-4 alkyl, phenyl optionally substituted with 
one or two substituents selected from halo, C.sub.1-4 alkyl, trihalo 
C.sub.1-4 alkyl and C.sub.1-4 alkoxy, or heterocyclic; and R.sup.3 and 
R.sup.4 are each C.sub.1-5 alkyl. 
The dihydropyridine compounds of this invention have excellent bradykinin 
antagonistic activity and are thus useful for the treatment of 
inflammation, cardiovascular disease, pain, common cold, allergies, 
asthma, pancreatitis, burns, virus infection, head injury, multiple trauma 
or the like in mammalia, especially humans. 
The present invention also provides a pharmaceutical composition for the 
treatment of medical conditions caused by bradykinin such as inflammation, 
cardiovascular disease, pain, common cold, allergies, asthma, 
pancreatitis, burns, virus infection, head injury, multiple trauma or the 
like, which comprises a therapeutically effective amount of the 
dihydropyridine compound of formula (I) or its pharmaceutically acceptable 
salt together with a pharmaceutically acceptable carrier. 
The present also provides a method for the treatment of disease conditions 
caused by bradykinin, in a mammalian subject, which comprises 
administering to said subject a therapeutically effective amount of a 
compound of formula (I). 
DETAILED DESCRIPTION OF THE INVENTION 
As used herein, the term "C.sub.1-4 alkylamino" and by "C.sub.1-4 
dialkylamino" mean N(R')R", wherein R' is hydrogen or C.sub.1-4 alkyl and 
R" is C.sub.1-4 alkyl, such as methylamino, ethylamino, n-propylamino, 
isopropylamino, p-butylamino, t-butylamino, dimethylamino, diethylamino 
and ethylmethylamino; 
the term "C.sub.5-14 cycloalkyl, bicycloalkyl or tricycloalkyl" means 
monocyclic, bicyclic or tricyclic alkyl having 5 to 14 carbon atoms, such 
as cyclopentyl, cycloheptyl, cyclooctyl, bicyclo3.2.1!octyl, 
bicyclo3.3.0!octyl and tricyclo4.3.3.0!dodecyl; 
the term "C.sub.7-14 azacyclo-, azabicyclo- or azatricyclo-alkyl" means 
monocyclic, bicyclic or tricyclic alkyl having 7 to 14 carbon atoms and 
one nitrogen atom in the ring, such as quinuclidinyl, 
azabicyclo3.2.1!octyl, azabicyclo3.3.1!nonyl, and 
azatricyclo3.3.3.0!undecyl; and 
the term "heterocyclic" means a monocyclic or bicyclic hydrocarbon group 
which has one or more hetero atoms in the ring, preferably has 4 to 10 
carbon atoms and 1 to 3 heteroatoms, including piperidino, morpholino, 
thiamorpholino, pyrrolidino, pyrazolino, pyrazolidino, pyrazoryl, 
piperazinyl, furyl, thienyl, oxazolyl, tetrazolyl, thiazolyl, imidazolyl, 
imidazolinyl, pyrazolyl, pyridyl, pyrimidinyl, pyrrolyl, pyrrolidinyl and 
quinolyl. 
In the above (I), preferably, R.sup.1 is selected from group (a); R.sup.2 
is hydrogen, C.sub.1-4 alkyl or phenyl optionally substituted with one or 
two substituents selected from halo, C.sub.1-4 alkyl, trihalo C.sub.1-4 
alkyl and C.sub.1-4 alkoxy; and R.sup.3 and R.sup.4 are each C.sub.1-3 
alkyl. 
Among these, more preferably X.sup.1 is CH.sub.2 or CO; R.sup.1 is 
N-morpholinomethylphenyl, t-butoxycarbonyl, acetyl, guanidinopropyl, 
4,5-dihydroimidazole-2-propyl, 4,5-dihydroimidazol-2-yl or guanidinoethyl. 
Furthermore in the above formula (I), A.sup.1 and A.sup.2 may be the same 
as or different from each other, and are selected from chloro, bromo, iodo 
and fluoro, preferably chloro and bromo. 
In the above formula (I), X.sup.1 is preferably a direct bond or CH.sub.2 
In the above formula (I), examples of R.sup.1 selected from group (b) are 
hydrogen, pyridyl, pyrrolidinylcarbonyl, propylaminocarbonyl, hydroxyethyl 
and dimethylaminopropyl. 
Examples of R.sup.1 selected from group (c) are piperidinyl, 
1-(butoxycarbonyl)piperidinyl and 1-methylpiperidinyl. 
Examples of R.sup.1 selected from group (d) are C.sub.5-6 cycloalkyl, 
bicyclo3.2.1!octyl and one of the following: 
##STR3## 
(wherein R.sup.6 is hydrogen and R.sup.7 is hydroxy, amino, 
methoxybenzamido or morpholino, or R.sup.6 and R.sup.7 are taken togerther 
to represent an oxo group). 
Examples of R.sup.1 selected from group (e) are the following groups: 
##STR4## 
(wherein R.sup.8 is hydrogen, formamidino, 4,5-dihydroimidazole-2-yl, 
C.sub.1-4 alkyl, benzyl optionally substituted with one or two 
substituents selected from halo and trihaloalkyl, acetyl or 
chloroethoxycarbonyl). 
Examples of R.sup.1 selected from group (f) are norbornenyl, indanonyl, 
quinuclidinyl or pyrimidinyl. 
In the above formula (I), examples of R.sup.2 are hydrogen, phenyl, 
methoxyphenyl, propyl(methoxy)phenyl, methylphenyl, chlorophenyl, pyridyl 
and thienyl. 
In the above formula (I), examples of R.sup.3 and R.sup.4 are methyl, 
ethyl, propyl, t-butyl, s-butyl and pentyl, preferably C.sub.1-3 alkyl 
such as methyl and ethyl. 
Of these compounds, the preferred compounds are: dimethyl 
4-(2,6-dichlorophenyl)-2-4-(3-guanidinopropyl)-1-piperazinyl!carbonylmeth 
yl-6-(2-phenylethyl)-1,4-dihydropyridine-3,5-dicarboxylate dihydrochloride; 
dimethyl 
4-(2,6-dichlorophenyl)-2-{4-3-(4,5-dihydroimidazole-2-yl)propyl!1-piperaz 
inyl}carbonylmethyl-6-(2-phenylethyl)-1,4-dihydropyridine-3,5-dicarboxylate 
hydrochloride, hydriodide; dimethyl 
4-(2,6-dichlorophenyl)-2-4-(4,5-dihydroimidazole-2-yl)-1-piperazinyl!carb 
onylmethyl-6-(2-phenylethyl)-1,4-dihydropyridine-3,5-dicarboxylate 
hydriodide; and dimethyl 
4-(2,6-dichlorophenyl)-2-4-(2-guanidinoethyl)-1-piperazinyl!carbonylmethy 
l-6-(2-phenylethyl)-1,4-dihydropyridine-3,5-dicarboxylate dihydrochloride. 
General Synthesis 
The dihydropyridine compounds of formula (I) of this invention may be 
prepared by a variety of synthetic methods known to those skilled in the 
art. For example, the dihydropyridine compounds of formula (I), wherein 
X.sup.2 is CO and Y is 1,4-piperazinyl-(CH.sub.2).sub.n -- or 
--N(R.sup.5)--(CH.sub.2).sub.n --, may be prepared by reaction of compound 
(II) with compound (III-a) or (III-b), followed, if desired, by conversion 
of a compound in which R.sup.1 is H into a compound in which R.sup.1 is 
other than H, as indicated in the following Preparation Method A-I. 
##STR5## 
(wherein Z is hydrogen or lower alkyl such as methyl and ethyl; and the 
other symbols are as already defined, with proviso that X.sup.1 is 
CH.sub.2, protected carbonyl, sulfide or sulfoxide) 
In Preparation Method A-I, when Z is lower alkyl, the compound (II) may be 
first subjected to selective saponification of the ester residue at the 
2-position of the compound (II), followed by acidification to afford a 
free acid, which is coupled with the compound (III-a) or (III-b) to give 
the dihydropyridine compound (I-a) or (I-b). In this case, when X.sup.1 is 
carbonyl, the carbonyl may be protected by a conventional protecting group 
which is removed in an appropriate step by conventional means. A suitable 
protecting group for a carboxy group is, for example, a C.sub.1-4 alkyl 
(especially methyl or ethyl) which may be removed by hydrolysis with a 
suitable base such as an alkali metal hydroxide (e.g., lithium or sodium 
hydroxide). When Z is H, the compound (II) may be directly coupled with 
the compound (III-a) or (III-b) to obtain the dihydropyridine compounds 
(I-a) or (I-b). 
The selective saponification and the acidification may be carried out by 
conventional procedures. In a typical procedure, the selective 
saponification is carried out by treatment with 2N sodium hydroxide in 
aqueous methanol. In a typical procedure, the acidification is carried out 
by treatment with 1N hydrochloric acid in a suitable reaction-inert 
solvent. 
The coupling reaction between the obtained acid and the compounds of the 
formula (III-a) or (III-b) may be carried out in a reaction-inert solvent 
as listed above (preferably dichloromethane) using a coupling agent such 
as dicyclohexylcarbodiimide (DCC), water soluble carbodiimide (WSCD), 
2-ethoxy-N-ethoxycarbonyl-1,2-dihydroquinoline, Bop agent 
(Benzotriazol-1-yloxy-tris(dimethylamino)phosphonium hexafluorophosphate), 
diethyl azodicarboxylate-triphenylphosphine, diethylcyanophosphonic acid 
and diphenylphospholylazide. This reaction may be carried out at a 
temperature in the range from -30.degree. to 40.degree. C., usually from 
0.degree. C. to 25.degree. C. for 10 minutes to 96 hours, usually 30 
minutes to 24 hours. 
A compound (I-a) or (I-b) wherein R.sup.1 is other than H and n is 0, can 
be obtained from the corresponding compound (I-a) or (I-b) wherein R.sup.1 
is H, by reductive alkylation of the terminal nitrogen with appropriate 
aldehyde or ketone. The reductive alkylation may be carried out in a 
suitable reaction-inert solvent, in the presence of a suitable reducing 
agent such as NABH.sub.4, NaBH.sub.3 CN or NaBH(OAc).sub.3 at a 
temperature in the range from -20.degree. to 120.degree. C., usually 0 to 
80.degree. C. for 10 minutes to 1 week, usually 30 minutes to 96 hours, 
optionally in the presence of molecular sieves. 
In addition, the compounds of the formula (III-a) and (III-b) as used 
herein may be either known or may be prepared by known methods. For 
example, the 4-N-substituted piperazines (wherein n is 0) may be prepared 
by means of (1) N alkylation of 4-N-protected piperazine with appropriate 
alkyl halide, R.sup.1 -halo, or (2) reductive amination of 4-N-protected 
piperazine with appropriate aldehyde or ketone in the presence of a 
reducing agent, followed by deprotection of the amino-protecting group. 
Suitable amino-protecting groups include, for example, benzyl, 
benzyloxycarbonyl and t-butoxycarbonyl group. Suitable reducing agents 
include, for example, sodium cyanoborohydride, aluminum-based reducing 
reagents, boranes, borohydrides or trialkylsilanes. After finishing 
introduction of a desired R.sup.1 group, the amino-protecting group is 
removed by a suitable standard procedure to provide the objective 
compound. When a compounds of the formula (I) wherein Y is 
2,3,4,5,6,7-hexahydro-1H-1,4-diazepinyl-(CH.sub.2).sub.n --, is required, 
2,3,4,5,6,7-hexahydro-1H-1,4-diazepinyl-(CH.sub.2).sub.n --R.sup.1 is used 
instead of the compound of the formula (III-a). 
Preparation Method A-II 
The compounds of formula (I) wherein X.sup.2 is CH.sub.2 may be prepared by 
the following method. 
##STR6## 
In Preparation Method A-II, when Z is lower alkyl, the compound (II) may be 
first subjected to Mannich type alkylation of the dichloromethane at the 
2-position of the compound (II) to give the adduct (IV-a) or (IV-b). The 
adduct (IV-a) or (IV-c) were subjected to selective saponification of the 
ester residue of the 2-position, followed by acidification to afford a 
free acid. The corboxylic acid is heated in an inert solvent to give the 
corresponding decarboxylated compound (I-c) or (I-d). Mannich type 
reaction may be carried out by conventional procedures. In a typical 
procedure, the Mannich alkylation may be carried out by treatment with, 
for example, 4-alkylpiperazine and paraformaldehyde in acetic acid. These 
reaction may be carried out at a temperature in the range from -10.degree. 
to 50.degree. C., usually from 0.degree. C. to 40.degree. C. for 30 
minutes to 24hours, usually 1 hour to 8 hours. The selective 
saponification and the acidification may be carried out by conventional 
procedures. In a typical procedure, the selective saponification is 
carried out by treatment with 2N sodium hydroxide in 1,4-dioxane. In a 
typical procedure, the acidification is carried out by treatment with 1N 
hydrochloric acid in a suitable reaction-inert solvent. These reaction may 
be carried out at a temperature in the range from 5.degree. to 50.degree. 
C., usually from 15.degree. C. to 30.degree. C. for 10 minutes to 2 hours, 
usually 20 minutes to 1 hour. The decarboxylation may be carried out by 
conventional procedures. In a typical procedure, the carboxylic acid is 
heated in a reaction inert solvent, (preferably toluene) at a temperature 
in the range from 70.degree. to 140.degree. C. usually from 90.degree. C. 
to 110.degree. C. for 15 minutes to 4 hours, usually 30 minutes to 2 
hours. When a compound of the formula (I) wherein Y is 
2,3,4,5,6,7-hexahydro-1H-1,4-diazepinyl-(CH.sub.2).sub.n --, is required, 
2,3,4,5,6,7-hexahydro-1H-1,4-diazepinyl-(CH.sub.2).sub.n --R.sup.1 is used 
instead of the compound of the formula (III-a). 
The compound (II) may be prepared by several methods as indicated in the 
following Preparation Methods B-I to B-III. 
##STR7## 
(wherein Z is hydrogen or lower alkyl such as methyl and ethyl; and the 
other symbols are as already defined, with proviso that X.sup.1 is 
CH.sub.2, protected carbonyl, sulfide or sulfoxide) 
This method utilizes the modified Hantzsch synthesis as described in A. 
Sausins and G. Duburs, Heterocycles, 1988, 27, 269. In this method, 
beta-keto ester (V) is first reacted with substituted benzaldehyde (VI) to 
obtain compound (VII). This reaction may be carried out in a suitable 
reaction-inert solvent. Suitable solvents include, for example, aromatic 
hydrocarbons such as benzene, toluene and xylene; alcohols such as 
methanol, ethanol, propanol and butanol; ethers such as ethyl ether, 
dioxane and tetrahydrofuran; halogenated hydrocarbons such as methylene 
chloride, chloroform and dichloroethane; amides such as 
N,N-dimethylformamide; and nitrites such as acetonitrile. This reaction 
may be carried out at a temperature of 0.degree. C. to 200.degree. C., 
preferably from 80.degree. C. to 120.degree. C. for 30 minutes to 24 
hours, preferably 30 minutes to 6 hours. If desired, this reaction may be 
catalyzed by a base such as piperidine, pyridine or alkoxide, or by an 
acid catalyst such as acetic acid, TiCl.sub.4 or p-toluenesulfonic acid. 
Thereafter, compound (VII) as obtained above is reacted with compound 
(VIII) in the presence of, or absence of a suitable condensing agent such 
as Lewis acids, to obtain the pyridine compound of the formula (II). This 
reaction may be carried out in the presence of, or absence of the 
reaction-inert solvent as listed above. However, this reaction may 
preferably carried out in the absence of a solvent. This reaction may be 
carried out at a temperature of 0.degree. C. to 200.degree. C., 
preferably, from 60.degree. C. to 150.degree. C. for 30 minutes to 48 
hours, preferably 10 hours to 20 hours. 
In addition, the beta-keto esters (V) and the substituted benzaldehydes 
(VI) which can be used herein may be either already known or may be 
prepared by known methods. For example, the beta-keto esters (V) may be 
prepared according to the reported methods as shown in, for example, (1) 
D. Scherling, J. Labelled Compds. Radiopharm., 1989, 27, 599; (2) C. R. 
Holmquist and E. T. Roskamp, J. Org. Chem., 1989, 54, 3258; (3) S. N. 
Huckin and L. Weiler, J. Am. Chem. SC. ,1974, 96, 1082; (4) J. C. S. 
Perkin I, 1979, 529; and (5)Synthesis, 1986, 37; J. C. S. Chem. Commun., 
1977, 932). 
##STR8## 
(wherein all the symbols are as already defined) 
This method utilizes the three components Hantzsch reaction. In a typical 
procedure, the beta-keto ester (V), the substituted benzealdehyde (VI) and 
compound (VIII) may be heated together in a suitable reaction-inert 
solvent as listed above (preferably lower alkanols such as methanol and 
ethanol). Preferably, a small amount of a lower alkanoic acid such as 
acetic acid is added as catalyst. The reaction mixture may be heated at 
80.degree. C. to 200.degree. C., preferably from 100.degree. C. to 
140.degree. C. for 30 minutes to 1 week, usually 24 hours to 96 hours. 
##STR9## 
(wherein all the symbols are as already defined) 
This method also utilizes the three components Hantzsch reaction as 
mentioned above. The reaction conditions similar to the above can be also 
used in this method. 
The compound (IX), enamine may either be known compounds or may be prepared 
by known methods. For example, the enamine compounds (IX) may be prepared 
by reacting the beta-keto ester (V) with ammonia. More specifically, the 
beta-keto ester (V) may be dissolved in a suitable solvent as listed 
above. Excess amount of ammonia gas is introduced into the solution at a 
temperature of 0.degree. to 60.degree. C. Alternatively, a solution 
containing ammonia dissolved in the above solvent is added to the solution 
containing the beta-keto ester (V), and the resultant mixture is reacted 
at a temperature of 0.degree. to 60.degree. C., to obtain compound (IX). 
In this method, it is easier to modify the moiety --X--R.sup.2 to obtain 
the dihydropyridine compounds of formula (I) having a desired --CH.sub.2 
--X--R.sup.2 moiety attached to the 6 position of the pyridine ring of the 
dihydropyridine (I). 
The compounds of formula (I), and the intermediates shown in the above 
Preparation Methods can be isolated and purified by conventional 
procedures, such as recrystallization or chromatographic purification. 
As the dihydropyridine compounds of this invention possess at least one 
asymmetric center, they are capable of occurring in various stereoisomeric 
forms or configurations. Hence, the compounds can exist in separated (+)- 
and (-)-optically active forms, as well as in racemic or (.+-.)-mixtures 
thereof. The present invention includes all such forms within its scope. 
Individual isomers can be obtained by known methods, such as optically 
selective reaction or chromatographic separation in the preparation of the 
final product or its intermediate. 
Insofar as the dihydropyridine compounds of this invention are basic 
compounds, they are capable of forming a wide variety of different salts 
with various inorganic and organic acids. 
The acids which are used to prepare the pharmaceutically acceptable acid 
addition salts of the aforementioned dihydropyridine base compounds of 
this invention of formula (I) are those which form non-toxic acid addition 
salts, i.e., salts containing pharmaceutically acceptable anions, such as 
the chloride, bromide, iodide, nitrate, sulfate or bisulfate, phosphate or 
acid phosphate, acetate, lactate, citrate or acid citrate, tartrate or 
bi-tartrate, succinate, maleate, fumarate, gluconate, saccharate, 
benzoate, methanesulfonate, ethanesulfonate, benzenesulfonate, 
p-toluenesulfonate and pamoate (i.e., 
1.1'-methylene-bis-(2-hydroxy-3-naphthoate))salts. The acid addition salts 
can be prepared by conventional procedures. 
The dihydropyridine compounds of the present invention of formula (I) 
exhibit significant bradykinin receptor-binding activity and therefore, 
are of value in the treatment of a wide variety of clinical conditions in 
mammals, especially man. Such conditions include inflammation, 
cardiovascular disease, pain, common cold, allergies, asthma, 
pancreatitis, burns, virus infection, head injury, multiple trauma and the 
like. 
Therefore, these compounds are readily adapted to therapeutic use as 
bradykinin antagonists for the control and/or treatment of any of the 
aforesaid clinical conditions in mammals, including humans. 
The activity of the dihydropyridine compounds of the present invention, as 
bradykinin antagonists, is determined by their ability to inhibit the 
binding of bradykinin at its receptor sites in IMR90 cells which express 
B.sub.2 receptor or A431 cells employing radioactive ligands. 
The bradykinin antagonist activity of the dihydropyridine compounds is 
evaluated by using the standard assay procedure described in, for example, 
Baenziger N. L., Jong Y-J. I., Yocum S. A., Dalemar L. R., Wilhelm B., 
Vaurek R., Stewart J. M., Eur. J. Cell Biol., 1992, 58, 71-80. This method 
essentially involves determining the concentration of the individual 
compound required to reduce the amount of radiolabelled bradykinin ligands 
by 50% at their receptor sites in rat, guinea pig or monkey tissues, or 
A431 or IMR90 cells, thereby affording characteristic IC.sub.50 values for 
each compound tested. 
More specifically, the assay is carried out as follows. First, rat, guinea 
pig or monkey ileum tissues are minced and suspended in 25 mM 
piperazine-N,N'-bis (2-ethanesulfonic acid (PIPES) buffer (pH 6.8) 
containing 0.1 mg/ml of soybean trypsin inhibitor. Then, the tissues are 
homogenized using a Polytron homogenizer at setting #6 for 30 seconds, and 
centrifuged at 30,000.times.g for 20 minutes. The pellets are homogenized 
with the same buffer, and recentrifuged. The tissue pellets, IMR90 cells 
or A431 cells are suspended in 25 mM PIPES buffer (pH6.8,) containing 1.25 
mM dithiothreitol, 1.75 .mu.g/ml bacitracin, 125 .mu.M o-phenanthroline, 
6.25 .mu.M captopril, 1.25 mg/ml bovine serum albumin (BSA), to prepare 
tissue/cell suspensions. Then, 10 .mu.l of test compound solution 
dissolved in phosphate buffered saline (PBS, pH 7.5) containing 2% DMSO 
(final) and 0.1% BSA (w/v) or 10 .mu.l of 12.5 .mu.M bradykinin in PBS (pH 
7.5) containing 0.1% BSA (w/v) are placed in a reaction 96-well plate. 15 
.mu.l of 8.3 nM 3H!bradykinin are added to the compound solution or 
bradykinin solution in the 96-well plate. Finally 100 .mu.l of the tissue 
or cell suspension are added to the mixture in the plate, and incubated at 
25.degree. C. for 1 hour. After incubation, the resultant product in the 
reaction plates is filtered through 0.1% polyethylenimine presoaked LKB 
filermat. The filtrate is washed using a Skatron auto cell harvester. The 
tissue bound radioactivity is determined using a LKB betaplate counter. 
The IC.sub.50 value is determined using the equation: 
EQU Bound=Bmax/(1+I!/IC.sub.50) 
wherein I! means the concentration of the test compound. 
Some compounds prepared in the Working Examples as described below were 
tested by this method, and showed an IC.sub.50 value of 10 nM to 1 .mu.M 
with respect to inhibition of binding at its receptor. 
The dihydropyridine compounds of formula (I) of this invention can be 
administered via either the oral, parenteral or topical routes to mammals. 
In general, these compounds are most desirably administered to humans in 
doses ranging from 0.3 mg to 750 mg per day, preferably from 10 mg to 500 
mg per day, although variations will necessarily occur depending upon the 
weight and condition of the subject being treated, the disease state being 
treated and the particular route of administration chosen. However, for 
example, a dosage O that is in the range of from 0.06 mg to 2 mg per kg of 
body weight per day is most desirably employed for the treatment of 
inflammation. 
The bradykinin antagonist activity of the dihydropyridine compounds in vivo 
is evaluated by a plasma leakage test. This test essentially involve 
determining the concentration of the individual compound required to 
reduce by 50% the amount of bradykinin-induced plasma leakage in rat 
urinary bladder, thereby affording characteristic ED.sub.50 values for 
each compounds tested. 
More specifically, the assay is carried out as follows. 3.5-week old male 
Sprague-Dawlew rats are purchased from Charles River Japan Inc. The rats 
are fed on stock diet (CRF from Charles River Japan, Inc.) and maintained 
under the standard conditions (temperature, 23.+-.1.degree. C. and 
humidity 55.+-.5%) for at least 3 days. The rats are fasted overnight 
prior to the experiments. Each test group consists of 5 rats. 
Bradykinin, purchased from Peptide Ins., is dissolved in the physiological 
saline (0.9% sodium chloride) at a concentration of 10 nmol/ml. The test 
dihydropyridine compounds are dissolved or suspended at different 
concentrations in the physiological saline solution containing 10 mg/ml 
Evans blue (Wako Pure Chemical, Japan). 
Captopril (5 mg/kg of body weight) is intraperitoneally (i.p.) injected to 
the rats, and 20 min later the rats are anesthetized by an administration 
of Nembutal (Abbott) (2.5 mg/kg of body weight). 5 min later, the test 
compound solution containing Evans blue is intravenously (i.v.) injected 
to the rats at a dose of 3 ml/kg of body weight. Another 5 min later, 
bradykinin is i.v. injected at a dose of 10 nmol/kg body weight. 
Thereafter, the rats are killed by dislocation of the neck and the urinary 
bladders are obtained. The urinary bladders are individually treated with 
1 ml of formamide at 60.degree. C. for at least 16 hours to extract Evans 
blue from the tissue. The absorvance of the extract is measured 
spectrophotometrically at 605 nm to determined the dye concentration. The 
effect of the individual test compound is calculated as a percentage of 
the amount of Evans blue leaked into the urinary bladder as compared to 
the control (saline for the test compounds). 
The dihydropyridine compounds of formula (I) of this invention can be 
administered via either the oral, parenteral or topical routes to mammals. 
In general, these compounds are most desirably administered to humans in 
doses ranging from 0.3 mg to 750 mg per day, preferably from 10 mg to 500 
mg per day, although variations will necessarily occur depending upon the 
weight and condition of the subject being treated, the disease state being 
treated and the particular route of administration chosen. However, for 
example, a dosage level that is in the range of from 0.06 mg to 2 mg per 
kg of body weight per day is most desirably employed for the treatment of 
inflammation. 
The compounds of the present invention may be administered alone or in 
combination with pharmaceutically acceptable carriers or diluents by 
either of the above routes previously indicated, and such administration 
can be carried out in single or multiple doses. More particularly, the 
novel therapeutic agents of the invention can be administered in a wide 
variety of different dosage forms, i.e., they may be combined with various 
pharmaceutically acceptable inert carriers in the form of tablets, 
capsules, lozenges, troches, hard candies, powders, sprays, creams, 
salves, suppositories, jellies, gels, pastes, lotions, ointments, aqueous 
suspensions, injectable solutions, elixirs, syrups, and the like. Such 
carriers include solid diluents or fillers, sterile aqueous media and 
various nontoxic organic solvents, etc. Moreover, oralpharmaceutical 
compositions can be suitably sweetened and/or flavored. In general, the 
therapeutically-effective compounds of this invention are present in such 
dosage forms at concentration levels ranging 5% to 70% by weight, 
preferably 10% to 50% by weight. 
For oral administration, tablets containing various excipients such as 
microcrystalline cellulose, sodium citrate, calcium carbonate, dipotassium 
phosphate and glycine may be employed along with various disintegrants 
such as starch and preferably corn, potato or tapioca starch, alginic acid 
and certain complex silicates, together with granulation binders like 
polyvinylpyrrolidone, sucrose, gelatin and acacia. Additionally, 
lubricating agents such as magnesium stearate, sodium lauryl sulfate and 
talc are often very useful for tabletting purposes. Solid compositions of 
a similar type may also be employed as fillers in gelatine capsules; 
preferred materials in this connection also include lactose or milk sugar 
as well as high molecular weight polyethylene glycols. When aqueous 
suspensions and/or elixirs are desired for oral administration, the active 
ingredient may be combined with various sweetening or flavoring agents, 
coloring matter or dyes, and, if so desired, emulsifying and/or suspending 
agents as well, together with such diluents as water, ethanol, propylene 
glycol, glycerin and various like combinations thereof. 
For parenteral administration, solutions of a compound of the present 
invention in either sesame or peanut oil or in aqueous propylene glycol 
may be employed. The aqueous solutions should be suitably buffered 
(preferably pH&gt;8) if necessary and the liquid diluent first rendered 
isotonic. These aqueous solutions are suitable for intravenous injection 
purposes. The oily solutions are suitable for intra-articular, 
intramuscular and subcutaneous injection purposes. The preparation of all 
these solutions under sterile conditions is readily accomplished by 
standard pharmaceutical techniques well-known to those skilled in the art. 
Additionally, it is also possible to administer the compounds of the 
present invention topically when treating inflammatory conditions of the 
skin and this may preferably be done by way of creams, jellies, gels, 
pastes, ointments and the like, in accordance with standard pharmaceutical 
practice.