Determination of moxifloxacin hydrochloride and its related substances by HPLC

An HPLC method was established for the determination of moxifloxacin hydrochloride and its related substances.The method was carried out on a Sepax BR-C₁₈ column (250 mm×4.6 mm,5 μm) with a mobile phase consisting of methanol-buffer solution (tetrabutyl ammonium hydrogen sulfate 0.5 g,KH₂PO₄ 1.0 g,H₃PO₄ 3.4 g in 1 L of purified water)（28∶72）at the flow rate of 1.3 mL/min.The detection wavelength was 293 nm and column temperature was 45 °C.The calibration curves were linear over the range of 38.55-57.82 μg/mL (r=0.999 8).The quantitative and detection limits were 0.025 μg/mL and 0.006 25μg/mL respectively.Good chromatographic separation of moxifloxacin hydrochloride and its related substances were obtained.As a result,the established HPLC method is simple,and could be used for the determination of moxiflocain hydrochloride and its related substances.