羧甲基-β-环糊精为手性选择剂的CE法检查R-维拉帕米中S-异构体杂质

目的:建立以羧甲基-β-环糊精(CM-β-CD)为手性选择剂的毛细管电泳法检查R-维拉帕米原料药中S-异构体杂质。方法:实验考察了CM-β-CD质量浓度、pH及缓冲溶液浓度对对映体分离的影响。优化后的毛细管电泳条件为毛细管柱为未涂壁熔融石英毛细管柱,背景电解质为30 mmol·L-1磷酸盐缓冲液,pH 4.0,手性选择剂为质量浓度为15 g·L^-1的CM-S-β-CD。结果:在上述毛细管电泳条件下,维拉帕米S-异构体与R-异构体能够实现良好分离,分离度>5.0。维拉帕米S-异构体在质量浓度为2.0~20μg·mL^-1范围内呈现良好的线性关系(r>0.999),加样回收率为95.5%~103.5%,该方法的精密度和重复性均良好。3批R-维拉帕米原料药经本法检测所含S-异构体杂质均小于0.2%。结论:所建立好的方法适于R-维拉帕米原料药中S-异构体杂质的检查。

Objective:To develop a CE method using carboxymethyl-β-cyclodextrin as a chiral selector for determination of enantiomeric impurity in R-verapamil active pharmaceutical ingredient(API).Methods:The influence of the concentration of carboxymethyl-β-cyclodextrin, pH and concentration of sodium dihydrogen phosphate on the separation was investigated.The final chromatographic condition was as follows.The separation of the enantiomers was performed in a fused-silica capillary tube, in the buffer of 30 mmol·L^-1 sodium dihydrogen phosphate with 15 g·L^-1 CM-β-CD as a chiral selector at pH 4.0.Results:R-verapamil and S-verapamil were well separated(R>5.0) in the above condition.This method was linear for enantiomers of verapamil in the range of 2.0-20μg·mL^-1 with correlation coefficients > 0.999.Accuracy was validated on the basis of quotient of the measured values and the added values and it ranged from 95.5% to 103.5%.The method was validated to be accurate and precise.The S-enantiomeric impurity of 3 batches of R-verapamil API was less than 0.2%.Conclusion:The developed method was proved to be suitable for the determination of enantiomeric impurity of R-verapamil API.