Validation of HPLC-UV for simultaneous analysis of moxifloxacin and ciprofloxacin in peritoneal fluid

Purpose: To develop and validate a novel HPLC-UV method that involves protein precipitation for quantifying ciprofloxacin and moxifloxacin in peritoneal fluid obtained from patients receiving treatment for continuous ambulatory peritoneal dialysis (CAPD). Methods: Ice-cold (0.1 %) trifluoroacetic acid in methanol (v/v) was used to precipitate proteins in the peritoneal fluid samples. Chromatographic separation was achieved with the use of Agilent Zorbax SB-C18 analytical column (150 mm x 4.6 mm; 3.5 μm) under optimum chromatographic separation conditions (mobile phase: methanol – 0.1 % trifluoroacetic acid (34:66, v/v), flow rate of 1 mL/min, column temperature of 35°C, UV detection at 285 nm). Validation was done in accordance with the International Council for Harmonization (ICH) M10 guideline. Results: Total run time was 13 min, validation process was linear (concentration range of 0.2 – 50 μg/mL) with correlation coefficients of 0.9987 and 0.9857 for ciprofloxacin and moxifloxacin, respectively. Relative recovery values and relative standard deviation (RSD) were acceptable. Based on ICH M10, precision and accuracy that were within-run and those that were between-run were good for the proposed method. Conclusion: The HPLC-UV method developed and validated for quantifying ciprofloxacin and moxifloxacin found in the peritoneal fluid taken from patients undergoing CAPD is reliable. This method may be applicable for therapeutic drug monitoring, and conducting further pharmacokinetic studies on moxifloxacin and ciprofloxacin.