埃索美拉唑及其光学异构体的亲和毛细管电泳手性拆分

Chiral separation of esomeprazole and its enantiomer by affinity capillary electrophoresis

以牛血清白蛋白为手性添加剂,建立埃索美拉唑对映体杂质检查的亲和毛细管电泳方法,并采用荧光光谱、圆二色光谱法,通过研究埃索美拉唑及光学异构体与牛血清白蛋白作用的热力学参数、焓熵驱动过程及蛋白构象变化对其拆分机理进行探讨。建立的电泳分离条件为：未涂层石英毛细管柱（50 cm×50μm,有效长度41.5 cm）,以pH 8.0的20mmol/L磷酸二氢钠-磷酸氢二钠缓冲液（含250μmol/L牛血清白蛋白和7%正丙醇）作为运行缓冲液,正向运行电压30kV,柱温25℃,检测波长302 nm,压力进样（5 kPa,5 s）。在优化的实验条件下,埃索美拉唑与其对映体的分离度大于1.8,对映体杂质的最低检测限和定量限分别为0.8和2.0μg/mL,在2-20μg/mL浓度范围内线性关系良好;平均回收率为100.4%,RSD小于2.0%。该方法可用于埃索美拉唑原料药的对映体杂质检查。

An affinity capillary electrophoresis （ACE） method with bovine serum albumin （BSA） as chiral selector was developed to test the enantiomeric impurity in esomeprazole. The mechanism of enantioseparation of esomeprazole and its enantiomer via BSA was investigated by fluorescence and circular dichroism spectrum for thermodynamic parameters, enthalpy entropy-driven process and the conformational changes of BSA. The optimal separation condition obtained was a running buffer consisting of 20 mmol/L sodium dihydrogen phosphate and disodium hydrogen phosphate with 250 ixmol/L BSA and 7% n-propanol at pH 8.0, a positive voltage of 30 kV, separation temperature at 25 ℃ and detection wavelength at 302 nm. The resolution of esomeprazole and its enantiomer was more than 1.8. The LOD and LOQ were 0. 8 μg/mL and 2.0 μg/mL respectively, for the enantiomer of esomeprazole, and the linear range was 2-20μg/mL. The average recovery of R-omeprazole was 100.4% （ RSD 〈 2.0% ）. This method could be applied to test the enantiomeric impurity of esomeprazole drug substances.