Capillary electrophoretic analysis of the antibiotic vancomycin in innovative microparticles and in commercial formulations

A new fast capillary electrophoretic method has been developed for the analysis of the glycopeptide antibiotic vancomycin in formulations. An electrophoretic run is completed within 3.0 min; fused silica capillaries (100 μm i.d., 8.5 cm effective length and 48.5 cm total length) and a background electrolyte consisting of 12.5 mM, pH 2.5 phosphate buffer are used. The applied voltage is −20.0 kV; samples are injected by pressure (30 mbar × 3 s) at the anodic end of the capillary. The method was successfully applied to innovative controlled release microparticles consisting of a coated albumin core containing vancomycin. A simple procedure has been developed to obtain complete vancomycin extraction from microparticles using a 5% (w/v) sodium dodecyl sulphate aqueous solution. The method has been validated in terms of linearity, precision and accuracy. Good linearity was found in the 0.25–5.00 μg/mL range. Satisfactory precision was obtained, with relative standard deviation values always lower than 3.9%; accuracy was satisfactory, with recovery values between 97.8 and 102.2%. The method is also suitable for vancomycin determination in commercial capsules.