Simultaneous quantification of venetoclax, busulfan and voriconazole in plasma by LC-MS/MS: Clinical applications in patients with acute myeloid leukemia.

[OBJECTIVE] To develop a novel approach for quantitative analysis of three pharmaceutical agents commonly employed in the treatment of hematological disorders (venetoclax, busulfan, and voriconazole) by liquid chromatography tandem mass spectrometry (LC-MS/MS).

[METHODS] The internal standards were venetoclax-d8 (venetoclax), busulfan-d8 (busulfan), and posaconazole (voriconazole), which were separated on a Phenomenex Kinetex® C (2.1 × 50 mm, 2.6 μm) column, and the multiple reaction monitoring was carried out in the positive ion mode of the SCIEX Triple Quad™ 5500. Protein precipitation pretreatment was performed using acetonitrile, with solvent A (2 mmol/L ammonium acetate dissolved in water containing 0.1% formic acid) and solvent B (acetonitrile solution containing 0.1% formic acid) as mobile phases. The flow rate was 0.8 mL/min, and the injection volume was 5 μL.

[RESULTS] The method was validated with regards to selectivity, lower limit of quantification, linearity, precision and accuracy, matrix effect and extraction recovery, dilution integrity, and stability. The runtime of each plasma sample was 3.1 min. The concentration ranges of the calibration curves were 50-10,000 ng/mL for venetoclax and voriconazole, and 15-3000 ng/mL for busulfan, with all the three correlation coefficients greater than 0.999. There were significant drug-drug interactions with venetocalx and voriconazole, and the incidence of adverse reactions was related to the venetoclax exposure in vivo. Concentrations of busulfan and voriconazole showed substantial interindividual variability.

[CONCLUSION] This study develops, with validation, a novel LC-MS/MS method for simultaneous determination of venetoclax, busulfan, and voriconazole, which is suitable for application to therapeutic drug monitoring in patients with acute myeloid leukemia.