Development and validation of a liquid chromatography–tandem mass spectrometry assay for the simultaneous quantitation of prednisolone and dipyridamole in human plasma and its application in a pharmacokinetic study

We have developed and validated an accurate, sensitive, and robust LC–MS/MS method that determines the concentration of CRx-102 (the combination of prednisolone and dipyridamole) in human plasma. In this method, prednisolone, dipyridamole, and the combined internal standards (IS) prednisolone-d₆ (IS for prednisolone) and dipyridamole-d₂₀ (IS for dipyridamole) were extracted from 100 μL human EDTA plasma using methylbutyl ether. Calibration curves were linear over a concentration range of 0.4–200 ng/mL for prednisolone and 5–3000 ng/mL for dipyridamole. The analytes were quantitatively determined using tandem mass spectrometry operated in positive electrospray ionization in a multiple reaction monitoring (MRM) mode. This validated method has been used successfully in clinical pharmacokinetic studies of CRx-102 in healthy volunteers.