title: [Separation of cefoperazone and its S-isomer and other related substances by micellar electrokinetic capillary chromatography].
abstract: The separation of cefoperazone, its S-isomer, impurity A and other unknown related substances by micellar electrokinetic capillary chromatography (MECC) using sodium dodecyl sulphate (SDS) as the micellar phase was investigated. The effects of pH, concentration of phosphate buffer solution, SDS micelle concentration, methanol volume fraction, applied voltage and temperature on the separation were studied. It was found that the migration of these compounds was affected by these factors, especially by pH of the solution. The elution, as well as the migration time and separation efficiency of cefoperazone, its S-isomer, impurity A and other related substances changed with the acidity of the solution. The optimized separation conditions consisted of a running buffer of 70 mmol/L sodium phosphate buffer, at pH 6.5, containing 100 mmol/L SDS, with an applied voltage of 15 kV and a temperature of 25 degrees C. An uncoated fused-silica capillary of 51.0 cm x 75 microm (42.5 cm of effective length) was used. The sample was injected into the column by pressure (5 kPa) for 5 s. The detection wavelength was set at 254 nm. Twenty-eight impurities in cefoperazone sodium could be detected. Cefoperazone sodium and the degradation products could be separated well. The method was applied to separate and determine cefoperazone and its related substances successfully.
authors.affiliation: National Institute for the Control of Pharmaceutical and Biological Products, Beijing 100050, China. zhwpxy@126.com
authors.forename: Huiwen
authors.initials: H
authors.lastname: Zhang
authors.forename: Changqin
authors.initials: C
authors.lastname: Hu
authors.forename: Mingzhe
authors.initials: M
authors.lastname: Xu
authors.forename: Yaping
authors.initials: Y
authors.lastname: Li
authors.forename: Taijun
authors.initials: T
authors.lastname: Hang
mesh_terms: D002438:Cefoperazone / Q000737:chemistry* / Q000302:isolation & purification*; D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D007536:Isomerism; D015203:Reproducibility of Results
chemical_list: D002438:Cefoperazone