Development of in vitro screening system for CYP based drug interaction

细胞色素P450亚型鉴定及药物相互作用预测。利用人肝微粒体和重组人CYP亚型鉴定了参与多种药物代谢的人CYP亚型。细胞色素P4501A1、细胞色素P3A4、细胞色素P2D6和细胞色素P2C19分别参与心得安、异丙吡胺、米安色林和5-羟色胺再摄取抑制剂的代谢。这些结果提示普萘洛尔与吸烟、异丙吡胺与红霉素、米安色林与奎尼丁、5-羟色胺再摄取抑制剂与奥美拉唑之间存在药物相互作用的可能性。临床研究表明，红霉素可显著提高阿普唑仑的血药浓度，部分患者与安定合用可使佐特平的血药浓度升高。利用人和大鼠肝微粒体和重组CYP亚型的体外研究，可以定量预测奥美拉唑的多态代谢。对于体外-体内尺度，提出了一些假设：(1)肝外代谢的贡献可以忽略不计，(2)奥美拉唑口服后完全吸收，(3)在我们使用的浓度范围内没有观察到代谢饱和。这些假设通过使用大鼠的体外和体内研究得到了验证。我们还展示了通过使用原代培养的肝细胞进行体外研究来预测苯巴比妥诱导酶的可能性。从体外研究可以预测体内最大诱导性和EC50值。

Identification of CYP isoforms and prediction of drug interaction. Human CYP isoforms involved in the metabolism of several drugs were identified by using human liver microsomes and recombinant human CYP isoforms. CYP1A1, CYP3A4, CYP2D6 and CYP2C19 were supposed to be involved in the metabolism of propranolol, disopyramide, mianserin and serotonin reuptake inhibitors, respectively. These results suggest the possibility of drug interaction between propranolol and smoking, disopyramide and erythromycin, mianserin and quinidine, and serotonin reuptake inhibitors and omeprazole.In vivo drug interaction studies. Clinical studies indicated that the administration of erythromycin significantly increased the plasme alprazolam concentration, and the plasma zotepine concentration of some patients was in creased by co-administration of diazepam.Quantitative prediction of in vivo drug metabolism from in vitro data. Polymorphic metabolism of omeprazole could be quantitatively predicted from in vitro studies using human and rat hepatic microsomes and recombinant CYP isoforms. Some assumptions were made for in vitro-in vivo scaling : (1) contribution of extra hepatic metabolism was negligible, (2) omeprazole was completely absorbed after oral administration, and (3) saturation of metabolism is not observed in the concentration range we used. These assumptions was validated by in vitro and in vivo studies using rat. We also showed the possibility of the prediction of enzyme induction by phenobarbital from in vitro studies using the primary cultured hepatocytes. Maximum inducibility and EC50 values in vivo could be predicted from the in vitro studies.