Validation of a sensitive HPLC/fluorescence method for assessment of ciprofloxacin levels in plasma and prostate microdialysate samples from rats

Chronic bacterial prostatitis treatment consists of broad‐spectrum antibiotic therapy for long periods of time. Drug penetration into the prostate makes the treatment a challenged. Ciprofloxacin is one of the most prescribed drugs for this treatment. A liquid chromatography with fluorescence detection method was developed and validated for determining ciprofloxacin concentrations in two different matrices: plasma and prostate microdialysate. Ciprofloxacin was separated on a C 18 column eluted with a mobile phase constituted of a mixture of 0.4% aqueous triethylamine:methanol:acetonitrile (75:15:10, v/v/v) and 0.4% aqueous triethylamine:acetonitrile (88:12, v/v) for microdialysate and plasma samples, respectively. Linearity was obtained over a concentration range of 5–1000 ng/mL (microdialysate) and 10–2000 ng/mL (plasma), with coefficients of determination ≥0.9956. Precision was determined from the analysis of six quality control samples and showed RSD values <11.1 and 7.4% for intra and inter‐assay precision, respectively. The accuracy ranged from 85.6 to 114.3%. The method was applied to a preliminary pharmacokinetic study to investigate ciprofloxacin concentrations in prostate, sampled by microdialysis, and plasma after a 7 mg/kg intravenous dose to Wistar rats. The method showed high sensitivity using only protein precipitation as plasma sample clean‐up and was successfully applied to investigate ciprofloxacin prostate penetration. Copyright © 2015 John Wiley & Sons, Ltd.