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 μg/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.