Development and validation of a UPLC-MS/MS method for simultaneous quantification of levofloxacin, ciprofloxacin, moxifloxacin and rifampicin in human plasma: Application to the therapeutic drug monitoring in osteoarticular infections

Background: Fluoroquinolones and rifampicin are antibiotics frequently used for the treatment of osteoarticular infections, and their therapeutic drug monitoring is recommended. The aim of this study was to develop and validate a rapid and selective method of simultaneous quantification of levofloxacin, ciprofloxacin, moxifloxacin and rifampicin with short pretreatment and run times in order to be easily used in clinical practice. Methods: After a simple protein precipitation of plasma samples, the chromatographic separation was performed using an ultra-performance liquid chromatography system coupled with mass tandem spectrometry in a positive ionization mode. The mobile phase consisted of a gradient elution of water-formic acid (100:0.1, v/v)-ammonium acetate 2 mM (A) and methanol-formic acid (100:0.1, v/v)-ammonium acetate 2 mM (B) at a flow rate at 0.3 mL/min. Results: Analysis time was 5 min per run, and all analytes and internal standards eluted within 0.85-1.69 minutes. The calibration curves were linear over the range from 0.5-30 mu g/mL for levofloxacin, ciprofloxacin, moxifloxacin and rifampicin with linear regression coefficients above 0.995 for all analytes. The intra-day and inter-day coefficients of variation were below 10 % for lower and higher concentration. This method was successfully applied to drug monitoring in patients with an osteoarticular infection. Conclusion: A simple, rapid, and selective liquid chromatography-tandem mass spectrometry method was developed and validated for the simultaneous quantification of levofloxacin, ciprofloxacin, moxifloxacin and rifampicin in human plasma. (C) 2020 Published by Elsevier B.V.