Analysis of pazufloxacin mesilate in human plasma and urine by LC with fluorescence and UV detection, and its application to pharmacokinetic study

A liquid chromatographic method for analysis of pazufloxacin mesilate in human plasma and urine has been developed and validated for selectivity, sensitivity, accuracy, precision, and stability in pharmacokinetic analysis. The sensitivity of the method was 0.02 μg mL^-1 in plasma and 0.5 μg mL^-1 in urine, with overall intra-day and inter-day precision (RSD < 10%) and accuracy (90-120%) acceptable for clinical pharmacokinetic analysis. Recovery from plasma and urine was 80-110% for both pazufloxacin mesilate and enoxacin, the internal standard. Pazufloxacin was stable in both plasma and urine, with no significant degradation under four different conditions. The method was successfully used in a preliminary study of the bioavailability of pazufloxacin mesilate in healthy human volunteers after intravenous administration of 300 and 500 mg.