Analysis of ofloxacin in plasma samples by high-performance liquid chromatography

Summary A sensitive HPLC method has been developed for determination of ofloxacin (OFL) in biological fluids. Sample preparation was performed by adding phosphate buffer (pH 7.4, 0.1m) then extraction with trichloromethane. OFL and the internal standard, sarafloxacin (SAR), were separated on a reversed-phase column with aqueous phosphate solution-acetonitrile, 80∶20, as mobile phase. The fluorescence of the column effluent was monitored at λ_ex 338 and λ_em 425 nm. The retention times were 2.66 and 4.24 min for OFL and SAR, respectively, and the detection and quantitation limits were 8 and 15 ng mL⁻¹, respectively. Plots of response against ofloxacin concentration were linear in the range 8 to 2000 ng mL⁻¹. Recovery was 92.9% for OFL.