Determination of flumequine and 7-hydroxyflumequine in plasma of sheep by high-performance liquid chromatography

A high-performance liquid chromatographic (HPLC) method for the simultaneous determination of flumequine and its metabolite 7-hydroxyflumequine in sheep plasma was described. The two compounds were extracted from 100 mu l of plasma by liquid-liquid extraction. Aliquots (100 mu l) were injected onto the HPLC system and separated on a LiChrospher Select B column with an isocratic system. The compounds were detected by fluorimetric detection for concentrations below 500 mu g/l and by UV detection for the concentrations exceeding 500 mu g/l. The range of the validated concentrations were 50 000 to 5 mu g/l and 500 to 10 mu g/l with mean recovery rates of 87+/-3% and 60+/-1% for flumequine and 7-hydroxyflumequine, respectively. (C) 1998 Elsevier Science B.V. All rights reserved.