Validation of a fast and reliable liquid chromatography-tandem mass spectrometry (LC-MS/MS) with atmospheric pressure chemical ionization method for simultaneous quantitation of voriconazole, itraconazole and its active metabolite hydroxyitraconazole in human plasma

Background: Voriconazole and itraconazole are two broad-spectrum antifungal triazole derivates administered for the prevention and in the treatment of invasive fungal infections. Their broad inter-and intra-individual pharmacokinetic variability and the high probability of drug-drug interactions justify therapeutic drug monitoring. Methods: After liquid-liquid extraction with tertbutyl methyl ether, chromatographic separation was achieved on a Zorbax Eclipse XDB-C18 column using gradient elution with 10 mM ammonium formate and acetonitrile. Detection was performed by a tandem mass spectrometer coupled to LC via an atmospheric pressure chemical ionization (APCI) and quantification was performed using selected reaction monitoring (SRM) transitions Results: Total run time was 4.5 min. The method was validated for concentrations ranging from 0.05 to 10 mu g/mL for voriconazole and from 0.025 to 5 mu g/mL for itraconazole and hydroxyitraconazole, respectively. The intra-and inter-day correlation coefficients of variation were <7.7%-<9.2%, respectively. The accuracy ranged from 92.6% to 109%. Conclusions: A rapid and simple liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry (LC-APCI-MS/MS) method has been developed and validated to measure voriconazole itraconazole and hydroxyitraconazole in human plasma. This method is successfully applied to samples from patients receiving antifungal treatment.