SIMPLE AND RAPID ANALYSIS OF PEFLOXACIN, FENBUFEN AND FELBINAC IN HUMAN PLASMA USING HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

A simple and reproducible method for the simultaneous determination of the antimicrobial agent pefloxacin and the anti-inflammatory drug fen bufen with its metabolite felbinac in human plasma is described. It in volves a two steps liquid-liquid extraction and separation using an Ad sorbosphere SAX column with ultraviolet detection at 280 nm. 2-[4-(2'- furoyl)phenyl]propionic acid is used as internal standard. The coeffic ients of variation are less than 5%. The lower limits of detection are 0.1, 0.3 and 0.1 mu g/mL for pefloxacin, fenbufen and felbinac, respe ctively. This method was found to be applicable to pharmacokinetic and pharmacodynamic studies of each drug after the concomitant administra tion of pefloxacin and fenbufen.