Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto-SP, Brazil.
Electrophoresis. 2011 Oct;32(19):2673-82. doi: 10.1002/elps.201100166.
A simple enantioselective method based on CE using CD as chiral selector was developed and validated for the determination of isradipine (IRD) enantiomers in a pharmaceutical formulation and for the determination of IRD enantiomers in degradation studies. After optimization, the best results were obtained using 15 mM borate buffer at pH 9.3 and sulfobutyl ether-β-cyclodextrin (2.5%, w/v) as chiral selector. The applied voltage was +30 kV, and the sample injection was performed in the hydrodynamic mode. All analyses were carried out in a fused-silica uncoated capillary with an id of 50 μm and total length of 60.0 cm. Under these conditions, a complete separation between IRD enantiomers was achieved in less than 7 min. Linearity was obtained in the range 50-300 μg/mL for both enantiomers (r≥0.9978). The RSD (%) and relative errors (%) obtained in precision and accuracy studies (intra-day and inter-day) were lower than 5%. Therefore, this method was found to be appropriate for controlling pharmaceutical formulations containing IRD enantiomers and the assay was considered to be stability indicating. The drug was subjected to oxidation, hydrolysis and photolysis. In all stress conditions the drug presented considerable degradation when compared with a fresh sample (zero time).
建立并验证了一种基于 CE 并使用 CD 作为手性选择剂的简单对映选择性方法，用于测定药物制剂中的异乐定（IRD）对映异构体和降解研究中的 IRD 对映异构体。经过优化，在 pH 9.3 的 15 mM 硼酸盐缓冲液和磺丁基醚-β-环糊精（2.5%，w/v）作为手性选择剂的条件下，获得了最佳结果。应用电压为+30 kV，采用液压模式进样。所有分析均在未涂层熔融石英毛细管中进行，内径为 50 μm，总长度为 60.0 cm。在这些条件下，IRD 对映异构体在不到 7 分钟内实现完全分离。两种对映异构体的线性范围均为 50-300 μg/mL（r≥0.9978）。精密度和准确度（日内和日间）研究中获得的 RSD（%）和相对误差（%）均低于 5%。因此，该方法适用于控制含有 IRD 对映异构体的药物制剂，并且该测定法被认为是稳定性指示的。该药物经历了氧化、水解和光解。在所有应激条件下，与新鲜样品（零时间）相比，药物都呈现出相当大的降解。
