Determination of Gemifloxacin in Plasma by HPLC

OBJECTIVE To establish a rapid HPLC method for determination of gemifloxacin in plasma. METHODS A Kromasil C₁₈ column(4.6 mm×250 mm, 5μm) was used at 40 ℃. Mobile phase was a mixture of CH3CN and 10 mmol·L^-1 ammonium acetate buffer (pH=2.2, containing 10 mmol·L^-1 perchloric acid) (22∶78). The flow rate was 1.5 mL·min^-1. The UV detector was operated at 338 nm. Plasma samples were treated by direct protein precipitation with 5% zinc sulfate-methanol solution. RESULTS The assay procedure was shown to produce linear calibration curves over the range of 0.05 μg·mL^-1 to 5 μg·mL^-1 of gemifloxacin in plasma(r=0.999 9). Within the range, the recovery rate was 93.2%-104.8%, and the RSD within-batch and between-batch were 1.8%~5.1% and 7.7%~8.5%, respectively. The detection limit of gemifloxacin was 0.02 μg·mL^-1. CONCLUSION This method is found to be reproducible, convenient and sensitive for bioavailability and clinical pharmacokinetics study of gemifloxacin.