代谢
奥美拉唑在肝脏中被细胞色素P450(CYP)酶系统广泛代谢。奥美拉唑的代谢物缺乏抗分泌活性。奥美拉唑的大部分代谢依赖于CYP 2C19同工酶,它形成羟基和去甲基代谢物。剩余的部分依赖于CYP 3A4,它形成磺酰代谢物。CYP 2C19同工酶在奥美拉唑的代谢中表现出多态性,因为大约3%的高加索人和15到20%的亚洲人缺乏CYP 2C19,被称为弱代谢者。在稳态下,弱代谢者的AUC与人群中其他人的AUC(广泛代谢者)的比例大约为2。在给予等摩尔剂量后,S-和R-异构体在肝脏中的代谢方式不同,导致S-异构体的血浆水平高于R-异构体。
Esomeprazole is extensively metabolized in the liver by the cytochrome P450 (CYP) enzyme system. The metabolites of esomeprazole lack antisecretory activity. The major part of esomeprazole's metabolism is dependent upon the CYP 2C19 isoenzyme, which forms the hydroxy and desmethyl metabolites. The remaining amount is dependent on CYP 3A4 which forms the sulphone metabolite. CYP 2C19 isoenzyme exhibits polymorphism in the metabolism of esomeprazole, since some 3% of Caucasians and 15 to 20% of Asians lack CYP 2C19 and are termed Poor Metabolizers. At steady state, the ratio of AUC in Poor Metabolizers to AUC in the rest of the population (Extensive Metabolizers) is approximately 2. Following administration of equimolar doses, the S- and R-isomers are metabolized differently by the liver, resulting in higher plasma levels of the S- than of the R-isomer.
来源:Hazardous Substances Data Bank (HSDB)