Vicagrel is a promising novel antiplatelet drug. However, the quantification of vicagrel in plasma is currently unavailable since it is liable to be hydrolyzed in plasma by esterases. In this study, an optimized strategy was developed and validated to stabilize vicagrel, 2-oxo-clopidogrel (thiolactone metabolite), and H4 (active thiol metabolite) before quantification of the analytes, such as addition of citric acid (for plasma acidification) and NaF (a non-specific esterase inhibitor) to inhibit esterase activity, immediate addition of a thiol-alkylating reagent MPB into blood samples to derivatize H4 for the formation of stable H4 derivative (i.e., MP-H4), use of the anticoagulant K2EDTA to minimize the conversion of 2-oxo-clopidogrel to H-endo, and keeping the analytes at 4 °C or on wet ice to minimize degradation of the analytes when processed and analyzed. The stability was measured as percent of each analyte remained in plasma samples after their storage for 4 h at 4 °C or in blood samples after 1 h at 4 °C. The results indicated that stability of vicagrel was increased significantly in stabilized plasma or blood samples compared with non-stabilized controls for rats and humans, respectively, and that the stability of 2-oxo-clopidogrel was increased to a certain extent. In contrast, MP-H4 formed was stable in plasma immediately after thorough mixture of MPB with blood. We conclude that the above strategy is useful for improving the stability of vicagrel, 2-oxo-clopidogrel, and H4 in rat or human plasma, and that vicagrel and its two major metabolites can be quantified accurately and simultaneously.
Keywords: Clopidogrel; Esterase inhibitor; Hydrolysis; Platelet; Stabilization; Vicagrel.
Copyright © 2019 Elsevier B.V. All rights reserved.