Development and validation of LC–ESI-MS method for sensitive, accurate and rapid determination of UC-781 in New Zealand white rabbit plasma

The highly potent non-nucleoside reverse transcriptase inhibitor UC-781 is under development as a potential microbicide to prevent sexual transmission of human immunodeficiency virus type 1 (HIV-1). A sensitive and reproducible liquid chromatography–mass spectrometric method has been developed and validated for the quantification of the drug in New Zealand white rabbit plasma after liquid–liquid extraction procedure. The method was validated over the range of 1–500 ng mL−1. Average recoveries of the extraction method were high and consistent: 72%. The method is accurate with average accuracies over three QC (n = 30) concentrations ranging from 99.9% to 106.1%, and precise (within-day and between-day precision measures ranging from 2.2% to 9.9% and 6.50% to 9.0%, respectively). Plasma from other three species proved that extraction method did no affect analyte and internal standard stability. Due to its critical and consequential use, this assay could be readily used for investigational or clinical monitoring of plasma concentrations for low concentration as 1 ng mL−1 without interference.