Pharmacokinetics
The concentrations of selnoflast were determined in a total of 260 human plasma samples (obtained during the study) using a validated liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) method. Sample analysis was performed after the addition of the internal standard by protein precipitation followed by LC‐MS/MS. The calibration range was between 40.0 ng/mL and 40000.0 ng/mL; the lower limit of quantification in human plasma was 40.0 ng/mL. Study samples were analyzed within the validated frozen storage stability timeframe of 371 days at −20°C and −70°C, the five validated freeze/thaw cycles, and proven room temperature storage stability of 24 h, in a total of six analytical runs. Five out of six runs met the acceptance criteria. The precision and accuracy (expressed as %RE) of the assay, as determined from the analysis of quality control samples, was satisfactory throughout the study.