Intestinal CYP3A4-mediated biotransformation and active efflux of absorbed drug by P-glycoprotein are major determinants of bioavailability of orally administered drugs.

• 肠CYP3A4介导的生物转化和P糖蛋白介导的药物主动泵出肠细胞是决定口服药物生物利用度的主要因素。