Simple high-performance liquid chromatographic assay for the determination of ciprofloxacin in human plasma with ultraviolet detection

A simple high-performance liquid chromatographic method is described for the quantitative analysis of ciprofloxacin in human plasma. Following protein precipitation from plasma by means of 6% perchloric acid, the upper layer which contains the analyte and the internal standard lomefloxacin, was analysed on a reverse phase column LiChrospher® 60 RP-select B (5 μm) (EcoCART® 125-3) with ultraviolet detection at 280 nm. The mobile phase was acetic acid 5%-methanol–acetonitrile (90:5:5, v/v/v). The assay was linear for ciprofloxacin over the concentration range of 0.050 to 6.00 μg ml−1. The limit of quantification (LOQ) was 0.050 μg ml−1. The method was successfully applied to a bioavailability study with five different ciprofloxacin formulations.