Simultaneous Determination of Venetoclax and Posaconazole in Human Plasma by UPLC-MS/MS: Application to Therapeutic Drug Monitoring in Acute Myeloid Leukemia Patients.

BACKGROUND

Due to the high risk of invasive fungal disease (IFD) in acute myeloid leukemia (AML) patients, the antifungal drug posaconazole is often co-administered with venetoclax. As posaconazole is a potent inhibitor of CYP3A4, the standard dosing regimen may lead to the elevated plasma concentrations of venetoclax due to potential drug-drug interactions (DDIs). Therefore, therapeutic drug monitoring (TDM) is necessary to optimize the dosage.

METHODS

This study developed and validated a rapid and sensitive ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for the simultaneous quantification of venetoclax and posaconazole in human plasma. Plasma samples were pretreated using acetonitrile precipitation. The chromatographic separation was achieved using an Acquity BEH C18 column with gradient elution. The mobile phase consisted of 0.1% formic acid in water and acetonitrile, with a flow rate of 0.4 mL/min.

RESULTS

The method demonstrated good sensitivity and linearity within the concentration ranges of 10-15,000 ng/mL for venetoclax and 10-10,000 ng/mL for posaconazole, respectively. Additionally, the method showed acceptable selectivity, intra-day precision, inter-day precision, accuracy, matrix effects (95.2% to 102.0% for venetoclax and 98.4% to 102.5% for posaconazole), extraction recovery (93.2% to 95.4% for venetoclax and 87.8% to 95.8% for posaconazole), and stability under various conditions. The trough concentrations of venetoclax were 9326.88 ± 12,169.05 ng/mL in patients treated with venetoclax alone, and 31,623.55 ± 28,453.67 ng/mL in patients treated with venetoclax in combination with posaconazole.

CONCLUSION

A rapid and simple method was established and successfully applied to the simultaneous determination of the concentrations of venetoclax and posaconazole in AML patients, providing a basis for TDM and clinical pharmacokinetic analysis of these drugs in AML patients.