title: Effect of common organic solvents on in vitro cytochrome P450-mediated metabolic activities in human liver microsomes.
abstract: In this study, we report the effect of methanol, dimethyl sulfoxide (DMSO), and acetonitrile on the cytochrome P450 (P450)-mediated metabolism of several substrates in human liver microsomes: phenacetin O-deethylation for P4501A2, coumarin 7-hydroxylation for P4502A6, tolbutamide hydroxylation for P4502C8/2C9, S-mephenytoin 4'-hydroxylation for P4502C19, dextromethorphan O-demethylation for P4502D6, chlorzoxazone 6-hydroxylation for P4502E1, and testosterone 6beta-hydroxylation for P4503A4. DMSO was found to inhibit several P450-mediated reactions (2C8/2C9, 2C19, 2E1, and 3A4) even at low concentrations (0.2%). There was no measurable effect on the catalytic activity of the various P450s when methanol was present at levels </=1%, except for P4502C8/9 and 2E1. Acetonitrile did not noticeably change the catalytic activity of the P4502C8/2C9, 2C19, 2D6, and 2E1 enzymes at concentrations </=1%. It was found that the content level of the organic solvents should be kept lower than 1% because, for all three solvents, a concentration of 5% strongly affected the metabolism of the various probes. These findings should be taken into consideration when designing in vitro metabolism studies of new chemical entities.
authors.affiliation: Merck Frosst Center for Therapeutic Research, Pointe-Claire Dorval, Quebec H9R 4P8, Canada.
authors.forename: N
authors.initials: N
authors.lastname: Chauret
authors.forename: A
authors.initials: A
authors.lastname: Gauthier
authors.forename: D A
authors.initials: DA
authors.lastname: Nicoll-Griffith
mesh_terms: D000097:Acetonitriles / Q000008:administration & dosage / Q000494:pharmacology; D000287:Administration, Topical; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage / Q000494:pharmacology; D065607:Cytochrome P-450 Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System / Q000187:drug effects* / Q000378:metabolism; D004121:Dimethyl Sulfoxide / Q000008:administration & dosage / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006801:Humans; D006900:Hydroxylation / Q000187:drug effects; D000432:Methanol / Q000008:administration & dosage / Q000494:pharmacology; D008862:Microsomes, Liver / Q000187:drug effects* / Q000201:enzymology*; D012997:Solvents / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D000097:Acetonitriles; D000893:Anti-Inflammatory Agents; D065607:Cytochrome P-450 Enzyme Inhibitors; D012997:Solvents; D003577:Cytochrome P-450 Enzyme System; D000432:Methanol; D004121:Dimethyl Sulfoxide; C032159:acetonitrile