Simultaneous determination of rifabutin and human serum albumin in pharmaceutical formulations by capillary electrophoresis

Abstract Capillary zone electrophoresis (CZE) was used for determination of rifabutin (RFB), an anti-tuberculosis antibiotic drug, in various pharmaceutical formulations. Apart from that, simultaneous determination of RFB and human serum albumin (HSA) was performed. Electrophoretic behaviour of RFB was examined at various pH levels. CE conditions: a quartz capillary tube (internal diameter 75 mm, effective length 50 cm, total length 60 cm), the capillary temperature was 25 °С, the voltage applied to the capillary tube was + 20 kV, the UV detection wavelength was 214 nm, hydrodynamic injection of the sample was performed at 30 mbar for 5 s, tetraborate buffer solution (0.01 М, рН 9.2). The obtained results are characterized by high efficiency (number of theoretical plates up to 260,000) and sufficient sensitivity (LOQ starting from 0.02 μg/ml for RFB). The obtained data are in good accord with both HPLC results (for RFB) and spectrophotometry (for HSA).