Cytochrome P450 Mediated Metabolism

Tolbutamide was purchased from Dr. Ehrenstorfer GmbH (Augsburg, Germany). 4-hydroxyTolbutamide and 6-hydroxychlorzoxazone were obtained from Toronto Research Chemicals Inc. (North York, Canada). Dextromethorphan, dextrorphan and chlorzoxazone were supplied by Sigma-Aldrich Co. (St Louis, MO, USA). Testosterone was obtained from International Laboratory Limited (San Bruno, CA, USA). 6β-hydroxytestosterone was purchased from BD Biosciences Co. (Woburn, MA, USA). Phenacetin, cortisone acetate, EB and EE were from National Institute for the Control of Pharmaceutical and Biological Products (Beijing, China). NADPH was obtained from Roche Diagnostics GmbH (Mannheim, Germany). All other reagents were of HPLC or analytical grade.