Molecular Sciences/Candidate Optimization and Discovery Biology, Bristol-Myers Squibb Company, 311 Pennington-Rocky Hill Road, Pennington, NJ 08534, USA.
J Pharmacol Exp Ther. 2011 Nov;339(2):589-96. doi: 10.1124/jpet.111.184895. Epub 2011 Aug 9.
The thienopyridine antiplatelet drugs, such as ticlopidine, clopidogrel, and prasugrel, require activation by cytochromes P450 in vivo to effectively block platelet aggregation. The study of the metabolic activation of these compounds has been hampered by the lability and reactivity of the ring-opened active metabolite (AM) and by the numerous metabolites that can be formed in such a transformation. We have developed a novel method whereby platelets are incubated with the cytochrome P450 and the thienopyridine of interest for various amounts of time, and the effects on ADP-driven platelet aggregation are directly examined. In this way, the platelet is used as a biosensor for detection of the AM. Using this method, cytochromes P450 capable of converting clopidogrel, prasugrel, and 2-oxo-clopidogrel to metabolites that inhibit ADP-induced platelet aggregation were identified as well as which cytochromes P450 were capable of catalyzing partial reactions (e.g., conversion of 2-oxo-clopidogrel to the AM). These studies show that, in vitro, CYP3A4/5, 2C19, and 2B6 are individually capable of converting clopidogrel and prasugrel to the AM and that the cytochrome P450 preference for these two thienopyridines is very similar.
噻吩并吡啶类抗血小板药物，如噻氯匹定、氯吡格雷和普拉格雷，需要在体内被细胞色素 P450 激活，才能有效地阻止血小板聚集。这些化合物的代谢激活研究受到开环活性代谢物（AM）的不稳定性和反应性以及在这种转化中可以形成的众多代谢物的阻碍。我们开发了一种新方法，即将细胞色素 P450 和感兴趣的噻吩并吡啶与血小板一起孵育一段时间，然后直接检查对 ADP 驱动的血小板聚集的影响。通过这种方式，血小板被用作检测 AM 的生物传感器。使用这种方法，鉴定出能够将氯吡格雷、普拉格雷和 2-氧代-氯吡格雷转化为抑制 ADP 诱导的血小板聚集的代谢物的细胞色素 P450，以及能够催化部分反应（例如，将 2-氧代-氯吡格雷转化为 AM）的细胞色素 P450。这些研究表明，在体外，CYP3A4/5、2C19 和 2B6 均可单独将氯吡格雷和普拉格雷转化为 AM，并且细胞色素 P450 对这两种噻吩并吡啶的偏好非常相似。
