Determination of lomefloxacin in plasma samples by HPLC with fluorescence detection. Application to pharmacokinetic studies

A sensitive HPLC method with fluorescence detection is described for the an alysis of lomefloxacin (LOM) in biological samples; sarafloxacin (SAR) is u sed as internal standard. Sample preparation was performed by adding phosph ate buffer (pH 7.4, 0.1 M) then extraction with trichloromethane. LOM and t he internal standard were separated by HPLC on a reversed-phase column with aqueous phosphate solution-acetonitrile, 80:20, as mobile phase. The conce ntrations of SAR and LOM eluting from the column (retention times 2.35 and 3.67 min, respectively) were monitored by fluorescence detection at lambda (ex) 338 and lambda (em) 425 nm, The detection and quantitation limits were 8 and 15 ng mL(-1), respectively Standard curves were linearly related to concentration in the range 8-2000 ng mL(-1). Recovery was found to be 104.8 % for LOM. The method was applied to the determination of LOM in plasma sam ples collected during pharmacokinetic studies.