Validation of a Reversed-Phase Ultra-High-Performance Liquid Chromatographic Method With Photodiode Array Detection for the Determination of Voriconazole in Human Serum and Its Application to Therapeutic Drug Monitoring.

BACKGROUND: Voriconazole is a broad-spectrum triazole antifungal agent. It is widely used in the treatment of invasive fungal infections in immunocompromised patients. Because the pharmacokinetics of voriconazole demonstrates considerable variability, monitoring its serum levels plays an important role in optimizing therapies against many clinically relevant fungal pathogens. The aim of this study was to validate a simple and rapid U-HPLC-PDA method with minimal sample preparation for routine therapeutic drug monitoring (TDM) of voriconazole.

METHODS: After protein precipitation with the internal standard solution (posaconazole 5.0 mg/L in acetonitrile), chromatographic separation was performed in 4 minutes using water and acetonitrile as mobile phases and an Acquity UPLC BEH HSS C18 column (2.1 × 100 mm, 1.7 µm). The temperature was set at 45°C and the flow rate was 0.4 mL/min. Photodiode array detection at 256 nm was used as detection system. The method was validated according international guidelines for linearity, accuracy, precision, selectivity, lower limit of quantitation, carry over, and stability under different conditions.

RESULTS: All performance parameters were within acceptance criteria, demonstrating that the validated method is fit for purpose. After assay validation, 115 serum samples collected from 41 patients were analyzed to report the experience of the laboratory in TDM of voriconazole. Results showed a large variability in voriconazole trough levels, suggesting that this drug should be frequently measured in patients under treatment to enhance therapies efficacy and improve safety.

CONCLUSIONS: In this study, a reproducible U-HPLC-PDA assay with a short analysis time, requiring only a small amount of serum, good accuracy and reproducibility was validated, which is suitable for routine TDM of voriconazole in serum.