Background
Voriconazole (VRZ) is a triazole antifungal used for treatment of invasive fungal infection, which is a life-threatening condition. Therapeutic drug monitoring is recommended for identifying the optimal dose in patients who have hepatic/renal impairment or reduced function of the CYP2C19 metabolizing enzyme.
Conclusion
This method is applicable for routine monitoring of patients' VRZ plasma level with fast and accurate runtime to assess CYP2C19 genotype.
Methods
One hundred microliters of sample plasma was extracted by protein precipitated with 200 μl of acetonitrile containing fluconazole as internal standard (IS). After vortexing and centrifugation, supernatant was dried and reconstituted with 100 μl of mobile phase (ACN: 0.1% formic acid in 10 mM Ammonium acetate) (50:50 v/v) before injected. The column was C18, 2.7 μm, 3.0 × 50 mm at flow rate of 0.5 ml/min with retention time of 0.5 and 0.75 min for VRZ and IS, respectively. The tandem mass spectrometer was set in multiple reactions monitoring (MRM) mode with the following transition; VRZ m/z 350.10→281.10 and 307.20→220.20 (IS).
Results
The accuracy and precision inter- and intra-day were less than 9%, over the range 0.05-10 μg/ml. The linearity was consistent (r2 = 0.9987) and recovery was more than 85.0% for both analyses.