Separation and determination of cefotaxime enantiomers in injections by capillary zone electrophoresis

Cefotaxime enantiomers have specific effects on Gram-negative bacteria. For quality control of cefotaxime it was necessary to establish a method for enantioseparation by capillary zone electrophoresis (CZE) using cyclodextrin (CD) as a chiral selector. The effects of various parameters on enantioseparation were studied. A fused silica capillary (40 cm effective length × 75 μm ID) was used. The cefotaxime enantiomers were separated on the baseline under conditions of 0.5 mmol/L CM-β-CD, 75 mmol/L NaH2PO4 buffer at pH 7.0 using UV detection at 280 nm. Applied voltage and capillary temperature were 20 kV and 25 °C, respectively. Under these conditions for enantioseparation, linear calibration curves were obtained in the range 2 ∼ 160 μg/mL. The limit of detection for both isomers was less than 0.5 μg/mL. The method was used for analysis of pharmaceutical preparations (dosage forms) of cefotaxime from various factories. A simple and specific CZE method was successfully demonstrated for the separation of cefotaxime enantiomers. The enantioseparation method should be established and this method should be used to control the quality of cefotaxime.