title: In vitro metabolism of a novel antithrombotic compound, S002-333, and its enantiomers: quantitative cytochrome P450 phenotyping, metabolic profiling and enzyme kinetic studies.
abstract: 1. S002-333, (2-(4'-methoxy-benzenesulfonyl)-2,3,4,9-tetrahydro-1H-pyrido (3,4-b) indole-3-carboxylic acid amide) is a novel potent antithrombotic molecule currently under development phase. It is the racemic mixture of two enantiomers, namely S004-1032 (R-form) and S007-1558 (S-form). 2. The contribution of five major isoenzymes, namely CYP2B6, 2C9, 2C19, 2D6 and 3A4 was quantified using recombinant P450s in the phase-I metabolism through relative activity factor approach. CYP2C19 was found to be the major contributor for S002-333 and S007-1558, while CYP3A4 showed greater involvement in S004-1032 metabolism. Chemical inhibition and immunoinhibition studies reconfirmed the results in human liver microsomes (HLM). 3. Four major phase-I metabolites of S002-333; M-1 and M-3 (oxidative), M-2 (O-demethylated) and M-4 (dehydrogenated) were characterized in HLM. These metabolites constituted 11.2, 11.3 and 21.5% of the parent in comparison with the net phase-I metabolism of 29.9, 31.4 and 38.3% of S002-333, S004-1032 and S007-1558, respectively. 4. Among CYP2C9, 2C19 and 3A4, the relative contribution of CYP2C9 was found to be maximum during M-1 through M-4 formation. Enzyme kinetic analysis for detected metabolites indicated that M-1 to M-3 followed classical hyperbolic kinetics, whereas M-4 showed evidence of autoactivation. In conclusion, the results suggest prominent role of CYP2C9, 2C19 and 3A4 isoforms for enantioselective disposition of S002-333 in vitro.
authors.affiliation: Pharmacokinetics and Metabolism Division, CSIR - Central Drug Research Institute , Lucknow, Uttar Pradesh , India .
authors.forename: Amrita
authors.initials: A
authors.lastname: Saxena
authors.forename: Girish K
authors.initials: GK
authors.lastname: Jain
authors.forename: Hefazat H
authors.initials: HH
authors.lastname: Siddiqui
authors.forename: Shom S
authors.initials: SS
authors.lastname: Bhunia
authors.forename: Anil K
authors.initials: AK
authors.lastname: Saxena
authors.forename: Jiaur R
authors.initials: JR
authors.lastname: Gayen
mesh_terms: D000911:Antibodies, Monoclonal / Q000737:chemistry; D002243:Carbolines / Q000737:chemistry*; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry*; D015195:Drug Design; D005343:Fibrinolytic Agents / Q000737:chemistry*; D006801:Humans; D006900:Hydroxylation; D007211:Indoles / Q000737:chemistry; D007527:Isoenzymes / Q000737:chemistry; D007700:Kinetics; D008862:Microsomes, Liver / Q000378:metabolism; D010641:Phenotype; D013237:Stereoisomerism; D013449:Sulfonamides / Q000737:chemistry*
chemical_list: C000592767:2-(4'-methoxybenzenesulfonyl)-2,3,4,9-tetrahydro-1H-pyrido(3,4-b)indole-3-carboxylic acid amide; D000911:Antibodies, Monoclonal; D002243:Carbolines; D005343:Fibrinolytic Agents; D007211:Indoles; D007527:Isoenzymes; D013449:Sulfonamides; C012382:indole-3-carboxylic acid; D003577:Cytochrome P-450 Enzyme System