Dansette Patrick M, Levent Dan, Hessani Assia, Bertho Gildas, Mansuy Daniel
Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques, UMR 8601 CNRS, Université Paris Descartes , Sorbonne Paris Cité, 45 Rue des Saints-Pères, 75270 Paris Cedex 06, France.
Chem Res Toxicol. 2013 May 20;26(5):794-802. doi: 10.1021/tx400083b. Epub 2013 Apr 9.
The antithrombotics of the tetrahydrothienopyridine series, clopidogrel and prasugrel, are prodrugs that must be metabolized in two steps to become pharmacologically active. The first step is the formation of a thiolactone metabolite. The second step is a cytochrome P450 (P450)-dependent oxidation of this thiolactone resulting in the formation of a sulfenic acid that is eventually reduced into the corresponding active thiol. It has been postulated that the sulfenic acid metabolite resulted from a nucleophilic attack of water on a highly reactive thiolactone sulfoxide derived from P450-dependent oxidation of the thiolactone primary metabolite. The data described in the present article are in complete agreement with this proposition as they show that it was possible to trap these thiolactone sulfoxides by a series of nucleophiles such as amines, thiols, or cyclopentane-1,3-dione (CPDH), an equivalent of dimedone that is used as a sulfenic acid trapping agent. HPLC-MS studies showed that various bis-adducts having incorporated two nucleophile molecules were formed in these reactions. One of them that resulted from the oxidation of 2-oxo-prasugrel by human liver microsomes in the presence of ethanolamine and CPDH was isolated and completely characterized by (1)H and (13)C NMR spectroscopy in addition to MS and MS(2) spectrometry. All metabolites derived from an attack of H2O or an amine at the CO carbon of the intermediate thiolactone sulfoxide existed as a mixture of two diastereomers having a cis configuration of the double bond, whereas those formed in the presence of thiols appeared as a mixture of four diastereomers with a cis or trans configuration of the double bond. This led us to propose tentative mechanisms for the previously reported formation of trans isomers of the active thiol metabolite of clopidogrel upon microsomal metabolism of this antithrombotic in the presence of thiols. The results described in this article showed that thiolactone sulfoxides are formed as reactive metabolites during the metabolism of clopidogrel and prasugrel and are able to react as bis-electrophiles with a variety of nucleophiles. The possible implications of the formation of these reactive metabolites in the pharmacological and/or secondary toxic effects of these drugs remain to be studied.
四氢噻吩并吡啶类抗血栓药物氯吡格雷和普拉格雷是前体药物，必须经过两步代谢才能具有药理活性。第一步是形成硫内酯代谢物。第二步是细胞色素P450（P450）依赖的该硫内酯氧化，生成亚磺酸，最终还原为相应的活性硫醇。据推测，亚磺酸代谢物是由水对硫内酯初级代谢物经P450依赖氧化产生的高反应性硫内酯亚砜进行亲核攻击而形成的。本文所述数据与这一观点完全一致，因为数据表明，通过一系列亲核试剂，如胺、硫醇或环戊烷 - 1,3 - 二酮（CPDH，一种用作亚磺酸捕获剂的二甲基酮类似物），可以捕获这些硫内酯亚砜。HPLC - MS研究表明，在这些反应中形成了各种结合了两个亲核试剂分子的双加合物。其中一个是在乙醇胺和CPDH存在下，人肝微粒体氧化2 - 氧代普拉格雷产生的，除了质谱和二级质谱外，还通过¹H和¹³C NMR光谱对其进行了分离和完全表征。所有源自水或胺对中间硫内酯亚砜的羰基碳进行攻击的代谢物均以双键具有顺式构型的两种非对映异构体的混合物形式存在，而在硫醇存在下形成的代谢物则以双键具有顺式或反式构型的四种非对映异构体的混合物形式出现。这使我们对先前报道的在硫醇存在下该抗血栓药物氯吡格雷微粒体代谢时活性硫醇代谢物反式异构体的形成提出了初步机制。本文所述结果表明，硫内酯亚砜是氯吡格雷和普拉格雷代谢过程中形成的活性代谢物，能够作为双亲电试剂与多种亲核试剂反应。这些活性代谢物的形成在这些药物的药理和/或继发毒性作用中的可能影响仍有待研究。
