Determination of enoxacin and ofloxacin by capillary electrophoresis with electrochemiluminescence detection in biofluids and drugs and its application to pharmacokinetics

A novel and sensitive method for the simultaneous determination of enoxacin and ofloxacin has been established using capillary electrophoresis (CE) coupled with electrochemiluminescence (ECL) detection based on the ECL enhancement of tri(2,2‐bipyridyl)ruthenium(II). The conditions for sample solvent type, CE separation and ECL detection were investigated systematically. The analytes were well separated and detected within 7 min. The limits of detection (S/N = 3) of enoxacin and ofloxacin are 9.0 × 10^?9 and 1.6 × 10^?8 mol/L, respectively. The precisions (RSD%) of intraday and interday are less than 2.1 and 4.0%, respectively. The limits of quantitation (S/N = 10) of enoxacin and ofloxacin are 3.2 × 10^?7 and 5.4 × 10^?7 mol/L in human urine samples and 4.1 × 10^?7 and 6.9 × 10^?7 mol/L in human serum samples, respectively. The recoveries of enoxacin and ofloxacin at different concentration levels in human urine, serum and eye drop samples are between 94.0 and 106.7%. The proposed method was successfully applied to the determination of the enoxacin and ofloxacin in human urine, serum and eye drop samples and the monitoring of pharmacokinetics of ofloxacin in human body. Copyright © 2009 John Wiley & Sons, Ltd.