Full-scan high resolution accurate mass spectrometry (HRMS) in regulated bioanalysis: LC–HRMS for the quantitation of prednisone and prednisolone in human plasma

A liquid chromatography–full scan high resolution accurate mass spectrometry (LC–HRMS) method for quantifying prednisone and prednisolone in human plasma using a quadrupole time-of-flight mass spectrometer (Q-TOF) was developed. Plasma samples were extracted using a liquid–liquid extraction procedure. Full scan data were acquired in the TOF only mode and extracted ion chromatograms were generated post-acquisition with the exact masses of the analytes. The calibration range was 5–2500 ng/mL, with a Lower Limit of Quantitation (LLOQ) of 5 ng/mL. The assay accuracy was between 98.4% and 106.3%. The between-run (inter-day) and within-run (intra-day) precision were within 1.7% and 2.9%, respectively. The matrix effect was between 0.98 and 1.10 for the six different lots of human plasma evaluated. Pooled incurred samples were analyzed by the method and the results matched those obtained from an LC–MS/MS method. In addition, qualitative information on phospholipids, and other endogenous components were also extracted from the full-scan data acquired.