Validated stability indicating assay of gemifloxacin and lomefloxacin in tablet formulations by capillary electrophoresis

A capillary zone electrophoretic (CZE) method has been developed for the determination of gemifloxacin and lomefloxacin in pharmaceutical tablet formulations. The CZE separation was performed using a 75 mu m x 35 cm fused silica capillary under the following conditions: 25 degrees C; applied voltage, 12 kV; 25 mM H3PO4-NaOH running buffer (pH 8.5). The detection wavelength was 254 nm. Flumequine was used as internal standard. The method was suitably validated with respect to linearity, limit of detection and quantification, accuracy, precision, specificity, and robustness. The calibration was linear from 5 to 50 mu g mL(-1) for gemifloxacin and 10 to 60 mu g mL(-1) for lomefloxacin, and the limit of detection and quantification were 2.93, 4.91 mu g mL(-1), and 3.87, 8.93 for gemifloxacin and lomefloxacin, respectively. Recoveries ranging from 94.4-108.6% were obtained for both drugs. The method was successfully applied to the determination of gemifloxacin and lomefloxacin in pharmaceutical tablets. Excipients present in the tablets and degraded products from different stress conditions did not interfere in the assay.