[Determination of ciprofloxacin in human serum by high-performance liquid chromatography]

A high-performance liquid chromatography method was developed for the rapid determination of ciprofloxacin in human serum. After protein precipitation, chromatographic separation of ciprofloxacin in plasma was achieved with an octyl column and 20 mmol/L phosphate buffer, methanol and acetonitrile 76/12/12 (v/v/v), pH 4, as mobile phase. Quantitative determination was monitored on a fluorescence detector using an excitation and emission wavelength of 278 and 450 nm, respectively. Enrofloxacin was used as internal standard. Calibration curve is linear over the range 0,12 to 20 microg/mL (r=0,9992). Limit of detection and limit of quantification are 0,04 and 0,12 microg/mL, respectively. Within-day coefficient of variation (2,0 to 3,1 %) and day-to-day coefficient of variation (4,3 to 5,5 %) at three different concentrations are sufficient. Relative recovery ranged from 91,1 to 94,0 % at three different concentrations. Each analysis requires no longer than 7 min.