title: In vitro metabolism of the calmodulin antagonist DY-9760e (3-[2-[4-(3-chloro-2-methylphenyl)-1-piperazinyl]ethyl]-5,6-dimethoxy-1-(4-imidazolylmethyl)-1H-indazole dihydrochloride 3.5 hydrate) by human liver microsomes: involvement of cytochromes p450 in atypical kinetics and potential drug interactions.
abstract: Human cytochrome P450 (P450) isozyme(s) responsible for metabolism of the calmodulin antagonist 3-[2-[4-(3-chloro-2-methylphenyl)-1-piperazinyl]ethyl]-5,6-dimethoxy-1-(4-imidazolylmethyl)-1H-indazole dihydrochloride 3.5 hydrate (DY-9760e) and kinetic profiles for formation of its six primary metabolites [M3, M5, M6, M7, M8, and DY-9836 (3-[2-[4-(3-chloro-2-methylphenyl)piperazinyl]ethyl]-5,6-dimethoxyindazole)] were identified using human liver microsomes and recombinant P450 enzymes. In vitro experiments, including an immunoinhibition study, correlation analysis, and reactions with recombinant P450 enzymes, revealed that CYP3A4 is the primary P450 isozyme responsible for the formation of the DY-9760e metabolites, except for M5, which is metabolized by CYP2C9. Additionally, at clinically relevant concentrations, CYP2C8 and 2C19 make some contribution to the formation of M3 and M5, respectively. The formation rates of DY-9760e metabolites except for M8 by human liver microsomes are not consistent with a Michaelis-Menten kinetics model, but are better described by a substrate inhibition model. In contrast, the enzyme kinetics for all metabolites formed by recombinant CYP3A4 can be described by an autoactivation model or a mixed model of autoactivation and biphasic kinetics. Inhibition of human P450 enzymes by DY-9760e in human liver microsomes was also investigated. DY-9760e is a very potent competitive inhibitor of CYP2C8, 2C9 and 2D6 (Ki 0.25-1.7 microM), a mixed competitive and noncompetitive inhibitor of CYP2C19 (Ki 2.4 microM) and a moderate inhibitor of CYP1A2 and 3A4 (Ki 11.4-20.1 microM), suggesting a high possibility for human drug-drug interaction.
authors.affiliation: Drug Metabolism & Physicochemistry Research Laboratories, R&D Division, Daiichi Pharmaceutical Co., Ltd., Toky, Japan. tachiroq@daiichipharm.co.jp
authors.forename: Shuko
authors.initials: S
authors.lastname: Tachibana
authors.forename: Yuko
authors.initials: Y
authors.lastname: Fujimaki
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Yokoyama
authors.forename: Osamu
authors.initials: O
authors.lastname: Okazaki
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Sudo
mesh_terms: D001189:Aryl Hydrocarbon Hydroxylases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002147:Calmodulin / Q000037:antagonists & inhibitors; D019388:Cytochrome P-450 CYP1A2 / Q000378:metabolism; D065609:Cytochrome P-450 CYP1A2 Inhibitors; D065731:Cytochrome P-450 CYP2C19; D065727:Cytochrome P-450 CYP2C8; D065729:Cytochrome P-450 CYP2C9; D019389:Cytochrome P-450 CYP2D6 / Q000378:metabolism; D065690:Cytochrome P-450 CYP2D6 Inhibitors; D019392:Cytochrome P-450 CYP2E1 / Q000378:metabolism; D065691:Cytochrome P-450 CYP2E1 Inhibitors; D051544:Cytochrome P-450 CYP3A; D065607:Cytochrome P-450 Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D006801:Humans; D066298:In Vitro Techniques; D007191:Indazoles / Q000378:metabolism*; D007700:Kinetics; D008862:Microsomes, Liver / Q000201:enzymology / Q000378:metabolism*; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism
chemical_list: C109602:3-(2-(4-(3-chloro-2-methylphenyl)1-piperazinyl)ethyl)5,6-dimethoxy-1-(4-imidazolylmethyl)-1H-indazol dihydrochloride 3.5 hydrate; D002147:Calmodulin; D065609:Cytochrome P-450 CYP1A2 Inhibitors; D065690:Cytochrome P-450 CYP2D6 Inhibitors; D065691:Cytochrome P-450 CYP2E1 Inhibitors; D065607:Cytochrome P-450 Enzyme Inhibitors; D007191:Indazoles; D011994:Recombinant Proteins; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; C450260:CYP2C9 protein, human; D065729:Cytochrome P-450 CYP2C9; D019392:Cytochrome P-450 CYP2E1; D001189:Aryl Hydrocarbon Hydroxylases; C045793:CYP2C19 protein, human; C450259:CYP2C8 protein, human; D019388:Cytochrome P-450 CYP1A2; D065731:Cytochrome P-450 CYP2C19; D065727:Cytochrome P-450 CYP2C8; D019389:Cytochrome P-450 CYP2D6; D051544:Cytochrome P-450 CYP3A; C510163:CYP3A4 protein, human