Development of an LC-MS/MS method for determination of 2-oxo-clopidogrel in human plasma

Simultaneous determination of clopidogrel, 2-oxo-clopidogrel, and the thiol metabolite of clopidogrel in human plasma by LC-MS/MS

Clopidogrel is a pro-drug which needs two-step metabolism to produce the active thiol metabolite. This study aimed to explore an efficient method to simultaneously determine the plasma clopidogrel, 2-oxo-clopidogrel (2-Oxo-CLP), and the clopidogrel active metabolite (CAM). A high-throughput liquid chromatography tandem mass spectrometry (LC-MS/MS) was therefore developed. The analytes were extracted from plasma by using methyl tert-butyl ether (MTBE). Chromatographic separation was performed on a C18 column under an isocratic elution, accompanied with acetonitrile and deionized water containing 0.1% formic acid. After optimizing the condition of LC-MS/MS, a stable linearity was observed in the standard curves over the concentration ranges of 0.05 to 50.0 ng/mL for clopidogrel, 0.5 to 50.0 ng/mL for 2-Oxo-CLP, and 0.5 to 100 ng/mL for clopidogrel active metabolite derivative (CAMD). The retention time was 4.78 minutes, 3.79 minutes, 3.59 minutes, and 4.82 minutes for clopidogrel, 2-Oxo-CLP, CAMD, and internal standard, respectively. Both the relative standard deviation and the relative error were within the requirement of operating criteria. No significant degradation of clopidogrel, 2-Oxo-CLP, and CAMD occurred under different storage conditions. This method was successfully validated in 3 patients with coronary artery disease. The results showed that the current LC-MS/MS method was efficient for simultaneously detecting clopidogrel, 2-Oxo-CLP, and CAM with fine linearity, accuracy, precision, and stability.

Development and validation of a UPLC-MS/MS method for simultaneous determination of vicagrel and its major metabolites in rat or human plasma: An optimized novel strategy for the stabilization of vicagrel

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.

Validated LC-MS/MS method for simultaneous quantification of seven components of Naodesheng in rat serum after oral administration and its application to a pharmacokinetic study

A simple, precise and reliable LC-MS/MS method was developed and validated for simultaneous quantification of vitexin, notoginsenoside R1, hydroxysafflor yellow A, ginsenoside Rd, puerarin, daidzein and senkyunolide I as components of Naodesheng (NDS) in rat serum. The Linearity ranges in rat serum were 0.045-4.5 μg/mL for vitexin, 0.0476-4.76 μg/mL for notoginsenoside R1, 0.0422-4.22 μg/mL for hydroxysafflor yellow A, 0.0426-4.26 μg/mL for ginsenoside Rd, 0.0436-4.36 μg/mL for puerarin, 0.026-2.6 μg/mL for daidzein, and 0.05-5 μg/mL for senkyunolide I, with the correlation coefficients greater than 0.99. The established method was validated in terms of intra- and inter-day precision and accuracy, recovery, matrix effect and stability. Furthermore, the method was successfully applied for pharmacokinetic study of these seven components in rat serum after oral administration of NDS.

A Review of Analytical Methods for the determination of Clopidogrel in Pharmaceuticals and Biological Matrices

P2Y12 belongs to a group of G protein-coupled (GPCR) purinergic receptors and is a receptor for adenosine diphosphate (ADP). The P2Y12 receptor is involved in platelet aggregation and acts as a biological target for treating thromboembolisms and other clotting disorders. The use of Clopidogrel (CLO) has improved the morbidity and mortality endpoints including cardiovascular death, recurrent myocardial infarction (MI) and stroke at 30 days after percutaneous coronary intervention (PCI). CLO is one such drug that specifically and irreversibly inhibits the P2Y12 subtype of ADP receptor. This review delivers a detail description of various analytical methods published for the estimation of CLO and its combinations in pharmaceuticals and biological matrices. The review highlights the basic as well as advanced techniques performed for estimating CLO. The most commonly used assay techniques were UV and Visible spectrophotometry, high performance liquid chromatography (HPLC), high performance thin layer chromatography (HPTLC), micellar liquid chromatography (MLC), micellar electro kinetic chromatography (MEKC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Despite other analytical methods employed for the assay of CLO, the review reveals that the technique of HPLC with UV detection was widely used.

Species Comparison of Pre-systemic Bioactivation of Vicagrel, a New Acetate Derivative of Clopidogrel

Previously we have found vicagrel, a new acetate derivative of clopidogrel, underwent hydrolysis to 2-oxo-clopidogrel and subsequent conversions to its pharmacological active metabolite (AM) and inactive carboxylic acid metabolite (CAM). This study demonstrated the interspecies differences of the vicagrel bioactivation by comparing the critical vicagrel metabolites formation in rats, dogs and human. The pharmacokinetic studies with rats and dogs were conducted after intragastric administration of vicagrel, followed by in vitro metabolism investigation in venous system, intestinal/hepatic microsomes from rats, dogs and human. An obvious disparity was observed in system exposure to AM (99.0 vs. 635.1 μg⋅h/L, p < 0.05) and CAM (10119 vs. 2634 μg⋅h/L, p < 0.05) in rats and dogs. It was shown that the cleavage of vicagrel was almost completed in intestine with great different clearance (53.28 vs. 3.643 L⋅h^-1⋅kg^-1, p < 0.05) in rats and dogs. With no further hydrolysis to CAM, the greatest clearance of AM (3.26 mL⋅h^-1⋅kg^-1) was found in dog intestine. In rat plasma, 2-oxo-clopidogrel was much more extensively hydrolyzed to CAM than in dog and human. Albeit similar hydrolysis clearance and AM production was observed among hepatic microsomes of the three species, the production velocity of CAM ranked highest in dogs (7.55 pmol/min/mg protein). Therefore, the unconformity of AM and CAM exposure cross species mainly came from the metabolism of 2-oxo-clopidogrel associated largely with tissue specificity and interspecies differences of esterases. In human, the pharmacokinetics of vicagrel might be more optimistic due to less inactivation hydrolysis before reaching liver.