西他沙星差向异构体的毛细管电泳分离

以γ-环糊精和D-苯丙氨酸为手性选择剂,采用毛细管区带电泳成功地分离了新型抗菌素西他沙星差向异构体。考察了添加剂的种类、浓度和缓冲溶液的pH对毛细管电泳分离西他沙星的影响。分离电压为15 kV,选用60 cm(有效长度52.5 cm)×50 μm i.d.的石英毛细管,缓冲溶液组成为10 mmol/L KH2PO4-K2HPO4(pH 4.5),10 mmol/L CuSO4,20 mmol/L γ-环糊精和 10 mmol/L D-苯丙氨酸。实验结果表明,添加剂的种类和浓度是影响西他沙星手性分离的重要因素,只有当 D-苯丙氨酸、铜离子和γ-环糊精同时存在并达到一定浓度时,西他沙星差向异构体在毛细管电泳中才具有良好的分离效果。该方法可用于西他沙星差向异构体的定量分析。

Separation of Sitafloxacin Epimers by Capillary Electrophoresis

Sitafloxacin epimers were separated by capillary zone electrophoresis using gamma-cyclodextrin (gamma-CD) and D-phenylalanine (D-Phe) as chiral selector. The effects of the concentrations of gamma-CD, D-Phe, Cu2+ and pH of buffer were investigated. An uncoated fused-silica capillary of 50 microm i.d. and 60 cm (effective length 52.5 cm) was used. The capillary temperature was maintained at 25 degrees C. Samples were injected under a pressure of 7 kPa for 5 s and separated at 15 kV. A baseline separation of sitafloxacin epimers was achieved with a background electrolyte of 10 mmol/L KH2PO4-K2HPO4(pH 4.5), 10 mmol/L CuSO4, 20 mmol/L gamma-CD and 10 mmol/L D-Phe. The linear range for sitafloxacin was 32 -400 mg/L (0.996). The relative standard deviations (RSDs) of migration time and peak area were less than 1.9% and 3.8% respectively. This method can be applied in qualitative and quantitative analysis for sitafloxacin epimers.