Development and validation of a LC/MS/MS method for quantifying the next generation calcineurin inhibitor, voclosporin, in human whole blood

A rapid, accurate, and reproducible liquid chromatography electrospray tandem mass spectrometry (LC/ESI–MS/MS) method was developed and validated for the therapeutic drug monitoring of voclosporin in human whole blood. Sample aliquots of 100 μL were processed utilizing a protein precipitation procedure that contained a mixture of methanol, 0.2 M ZnSO4, and deuterated voclosporin internal standard. Supernatant was injected onto a Zorbax SB-C8, 2.1 × 12.5 mm column (at 60 °C), and washed with water–acetonitrile, supplemented with 0.02% glacial acetic acid and 0.02 mM sodium acetate, to remove poorly retained components. After washing, water–MeOH (with 0.02% glacial acetic acid and 0.02 mM sodium acetate) was used to elute the voclosporin and internal standard to the Applied Biosystems/MDS-Sciex API3000 mass spectrometer for detection in multiple reaction monitoring. Analytical performance was assessed in the range of 1–200 ng/ml in whole blood. This method has been used to quantify concentrations of voclosporin in whole blood from healthy volunteers participating in a pharmacokinetic study.