HPLC ANALYSIS OF CIPROFLOXACIN AND CIPROFLOXACIN METABOLITES IN BODY-FLUIDS

An improved high-performance liquid chromatography (HPLC) procedure fo r the analysis of ciprofloxacin and three of its metabolites in plasma , serum and urine samples was developed. The previously published HPLC procedure described the isocratic separation of ciprofloxacin and thr ee ciprofloxacin metabolites in urine samples on a polystyrene-divinyl benzene reverse-phase column followed by quantitation using a UV detec tor. The present procedure involved the same chromatographic separatio n, but is also applicable to the analysis of plasma and serum as well as urine samples, and quantitation was based on fluorometric detection after postcolumn induction of fluorescence instead of UV detection. T he post-column induction of fluorescence was necessary because the M2 and M3 metabolites of ciprofloxacin have relatively weak native fluore scence? and induction enhanced the fluorometric signals of metabolites M2 and M3 forty-four-fold and eleven-fold, respectively. The observed enhancement of fluorescence may be attributed to the partial conversi on by UV light of metabolites M2 and M3 to metabolite M1 which has int ense native fluorescence. The lower quantitation limits of ciprofloxac in and metabolites M1, M2 and M3 were 0.05 mu g ml(-1), 0.01 mu g ml(- 1), 0.05 mu g ml(-1), and 0.5 mu g ml(-1), respectively. All four anal ytes were quantitated using one isocratic elution of either plasma or serum supernatant after the precipitation of proteins or the isocratic chromatography of diluted urine samples.