title: Identification and relative contributions of human cytochrome P450 isoforms involved in the metabolism of glibenclamide and lansoprazole: evaluation of an approach based on the in vitro substrate disappearance rate.
abstract: 1. The identification and relative contributions of human cytochrome P450 (CYP) enzymes involved in the metabolism of glibenclamide and lansoprazole in human liver microsomes were investigated using an approach based on the in vitro disappearance rate of unchanged drug. 2. Recombinant CYP2C19 and CYP3A4 catalysed a significant disappearance of both drugs. When the contribution of CYPs to the intrinsic clearance (CL(int)) of drugs in pooled human microsomes was estimated by relative activity factors, contributions of CYP2C19 and CYP3A4 were determined to be 4.6 and 96.4% for glibenclamide, and 75.1 and 35.6% for lansoprazole, respectively. 3. CL(int) of glibenclamide correlated very well with CYP3A4 marker activity, whereas the CL(int) of lansoprazole significantly correlated with CYP2C19 and CYP3A4 marker activities in human liver microsomes from 12 separate individuals. Effects of CYP-specific inhibitors and anti-CYP3A serum on the CL(int) of drugs in pooled human liver microsomes reflected the relative contributions of CYP2C19 and CYP3A4. 4. The results suggest that glibenclamide is mainly metabolized by CYP3A4, whereas lansoprazole is metabolized by both CYP2C19 and CYP3A4 in human liver microsomes. This approach, based on the in vitro drug disappearance rate, is useful for estimating CYP identification and their contribution to drug discovery.
authors.affiliation: Biopharmaceutical and Pharmacokinetic Research Laboratories, Fujisawa Pharmaceutical Co., Ltd, Osaka, Japan. yoichi_naritomi@po.fujisawa.co.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Naritomi
authors.forename: S
authors.initials: S
authors.lastname: Terashita
authors.forename: A
authors.initials: A
authors.lastname: Kagayama
mesh_terms: D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D000906:Antibodies / Q000008:administration & dosage; D001189:Aryl Hydrocarbon Hydroxylases / Q000037:antagonists & inhibitors / Q000378:metabolism; D065731:Cytochrome P-450 CYP2C19; D051544:Cytochrome P-450 CYP3A; D065607:Cytochrome P-450 Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005905:Glyburide / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D007654:Ketoconazole / Q000494:pharmacology; D007700:Kinetics; D064747:Lansoprazole; D008617:Mephenytoin / Q000031:analogs & derivatives* / Q000494:pharmacology; D008862:Microsomes, Liver / Q000378:metabolism; D006899:Mixed Function Oxygenases / Q000037:antagonists & inhibitors / Q000378:metabolism; D009853:Omeprazole / Q000031:analogs & derivatives* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism
chemical_list: D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D000906:Antibodies; D065607:Cytochrome P-450 Enzyme Inhibitors; D004791:Enzyme Inhibitors; C454675:N-3-benzylnirvanol; D011994:Recombinant Proteins; D064747:Lansoprazole; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; D001189:Aryl Hydrocarbon Hydroxylases; C045793:CYP2C19 protein, human; C104464:CYP3A protein, human; D065731:Cytochrome P-450 CYP2C19; D051544:Cytochrome P-450 CYP3A; C510163:CYP3A4 protein, human; D009853:Omeprazole; D008617:Mephenytoin; D007654:Ketoconazole; D005905:Glyburide