Ionic liquid based dispersive liquid-liquid microextraction followed by RP-HPLC determination of balofloxacin in rat serum

An efficient and environmentally friendly ionic liquid based dispersive liquid-liquid microextraction procedure for the determination of balofloxacin in rat serum by reverse phase high-performance liquid chromatography was developed and validated. The effects of ionic liquids, dispersive solvents, extractant/disperser ratios and salt concentrations on sample recovery and enrichment were studied. Among the ionic liquids investigated, 1-butyl-3- methylimidazolium hexafluorophosphate was found to be the most effective and the recovery was 99.5% at an extractant/disperser ratio of 0.43 by addition of 5.0% NaCl. A threefold increase in detection (0.01 mu g mL (-1)) and quantification (0.035 mg mL (-1)) limits was achieved when compared to protein precipitation. A linear relationship in the range of 0.04-10.0 mg mL (-1) with a correlation coefficient of (r(2)) 0.9998 was observed. The method was validated and applied to study the pharmacokinetics of balofloxacin in rat serum.