Simultaneous determination of levofloxacin and ciprofloxacin in microdialysates and plasma by high-performance liquid chromatography

The fluoroquinolones levofloxacin and ciprotloxacin were simultaneously determined in microdialysis and plasma samples by reversed-phase high-performance liquid chromatography (HPLC) and fluorescence detection. After a simple sample preparation step the analytes were separated in the isocratic mode within 12 min. The calibration curve for levofloxacin was linear from 0.0156 to 5 mug ml(-1) and 0.02-12.5 mug ml(-1) in microdialysates and plasma samples, respectively. The limits of quantification for levofloxacin and ciprofloxacin were 0.0156 and 0.1 mug ml(-1) in microdialysis samples, and 0.02 and 0.1 mug ml(-1) in plasma samples, respectively. Some experimental details concerning microdialysate dilution and plasma protein precipitation were described to ensure accurate quantitation. The assay can be used as a routine method to analyse microdialysis and plasma samples from clinical studies. (C) 2002 Elsevier Science B.V. All rights reserved.