Simultaneous analysis of gemifloxacin mesylate and its main synthetic impurity by an optimized capillary zone electrophoretic method

Abstract

A simple and rapid stability indicating capillary zone electrophoretic (CZE) method was validated for the simultaneous determination of gemifloxacin mesylate (GFM) and its main synthetic impurity. The method was performed with a fused-silica capillary (50 μm i.d.) maintained at 30 °C. The background electrolyte consisted of 25 mM borate buffer (pH 10) and the separation was achieved applying 30 kV. The samples were injected hydrodynamically (6 s at 50 mbar) and detection was done at 220 nm. The procedure was validated by specificity, limit of detection (LOD), limit of quantification (LOQ), linearity, accuracy, precision and robustness. Degradations were performed in 0.1 M HCl, 0.01 M NaOH, 30% H₂O₂, moist heat at 60 °C and exposure to UV-A radiation to show the specificity and stability-indicating capability. Otherwise the excipients did not interfere with the quantitation of GFM. The method was linear for GFM (20.0–80.0 μg mL⁻¹) and its synthetic impurity (3.0–20.0 μg mL⁻¹). LOD and LOQ were 1.0 and 3.0 μg mL⁻¹, respectively, for synthetic impurity. The results of precision and accuracy showed values that agreed with the literature and the Plackett–Burman experimental design applied confirmed the robustness. The proposed method was used for the quantitative analysis of GFM and its synthetic impurity.