Determination of the Active Metabolite of the Prodrug Repirinast in Human Plasma by a Liquid Chromatography-Tandem Mass Spectrometry Method

Repirinast is a prodrug for the treatment of asthma. This paper describes the development of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the analysis of its active metabolite (MY-1250) in human plasma. The LC-MS/MS was operated under multiple reaction monitoring (MRM) mode using the electrospray positive ionization technique. The transition ions m/z 286.1 -> 498.2 and m/z 171.3 -> 0.26.2 were selected for the quantification of MY-1250 and internal standard (I.S.). The linear range was 2-15000 ng/mL. The absolute recoveries were 87.5 and 93.9% for MY-1250 and I.S. Within-run and between-run precision were lower than 6.2%. This method was reproducible and reliable, and was successfully used to analyze human plasma samples for application in a pharmacokinetic study.