DETERMINATION OF ENROFLOXACIN IN CHICKEN PLASMA BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY FOR PHARMACOKINETIC STUDIES

A simple rapid liquid chromatography method for determination of enrofloxacin in chicken plasma was developed. Samples were prepared by protein precipitation with acetonitrile/ammonia mixture and dichloroethane extraction. Analytical separation was performed in a gradient grade on a Phenomenex Gemini C18 column and analytes were detected by fluorescence (lambda(ex) = 300 nm and lambda(em) = 448 nm). The acidified mobile phase (pH = 3.8) was a mixture of acetonitrile and 0.05 M acetate buffer The method was linear in the range 0.2 - 3.5 mu g/mL, limit of detection was 40 ng/mL and limit of quantification was 120 ng/mL. The assay was accurate and precise and the mean recovery of enrofloxacin was 90.07 +/- 0.89 %. The suitability of the assay for pharmacokinetic studies was determined by measuring enrofloxacin concentrations in chicken plasma after a single intravenous administration of the drug at a dose of 10 mg/kg. Enrofloxacin concentration decreased from 4.17 mu g/mL in 5 min to 0.32 mu g/mL 24 hours after drug administration. The obtained results confirmed the suitability of the method for enrofloxacin determination.