Dispersive liquid–liquid microextraction based on the solidification of a floating organic droplet combined with high-performance liquid chromatography with ultraviolet detection (HPLC-UV) was developed for the determination of clevidipine and its primary metabolite in Sprague-Dawley rat plasma samples. During the extraction procedure, to facilitate an efficient procedure, the plasma protein was precipitated first by using a mixture of a zinc sulfate solution and acetonitrile. Several extraction parameters were carefully evaluated and optimized, including the type and volume of the extraction solvent, salt effect, pH and extraction time. Under the optimum conditions, the limits for quantification were 2.5 and 5.0 ng mL−1 for clevidipine and its primary metabolite, respectively. Sufficient linearity of clevidipine or its primary metabolite was observed with the coefficient of correlation (r) above 0.9979. The method showed good precision and accuracy, with intra- and inter-assay coefficients of variation <6.1% at all concentrations. The proposed pretreatment technique with HPLC was successfully applied to the determinate of clevidipine and its primary metabolite in rat plasma samples. Furthermore, the method, which requires less time than conventional techniques, is environmentally friendly and requires only a small amount of low-toxicity extraction solvent.
Eleven potential impurities, including process-related compounds and degradation products, have been analyzed by comprehensive studies on the manufacturing process of clevidipine butyrate. Possible formation mechanisms could also be devised. MS and NMR techniques have been used for the structural characterization of three previously unreported impurities (Imp-3, Imp-5 and Imp-11). To separate and quantify the potential impurities in a simultaneous fashion, an efficient and advanced RP-HPLC method has been developed. In doing so, four major degradation products (Imp-2, Imp-4, Imp-8 and Imp-10) can be observed under varying stress conditions. This analytical method has been validated according to ICH guidelines with respect to specificity, accuracy, linearity, robustness and stability. The method described has been demonstrated to be applicable in routine quality control processes and stability evaluation studies of clevidipine butyrate.
危险品化学品经营许可证（带存储）