Liquid chromatography-tandem mass spectrometry method for simultaneous quantification of four triazole antifungal agents in human plasma

Background: Invasive fungal infections are an increasing cause of morbidity and mortality. Triazole antifungal agents are recommended for the prevention and treatment of such infections. Their broad inter-and intra-individual pharmacokinetic variability and the high probability of drug-drug interactions justify therapeutic drug monitoring (TDM). We developed a liquid chromatography-tandem mass spectrometry method for the simultaneous quantification of four triazole antifungal agents (fluconazole, itraconazole, posaconazole, voriconazole) and one of their metabolites (hydroxy-itraconazole) in human plasma. Methods: After protein precipitation with acetonitrile (ACN), a C18 column was used for separation with a mobile phase consisting of 0.1% formic acid, water and ACN in a linear gradient from 20% to 70%, over 10 min. Detection was performed by electrospray ionization and quantification was performed using selected reaction monitoring transitions. Results: Total run time was 15 min. The method was validated for a range of 0.1-12 mu g/mL. Coefficients of variation were <9.5% and <13.8%, and accuracies were between <5.4% and +7.7% and between -10.8% and +10.4%, for intra-and inter-day validations, respectively. Conclusions: This method appears to be well suited to routine hospital practice for the TDM of triazole antifungal agents considering its time of analysis, range of concentrations measured, precision and accuracy. Clin Chem Lab Med 2010;48:1515-22.