UHPLC-MS/MS-based method for quantification of verinurad in rat plasma and its application in a bioavailability study

A rapid and sensitive UHPLC-MS/MS method was developed and fully validated for the quantification of verinurad in rat plasma. Lesinurad was used as an internal standard (IS), and simple protein precipitation was utilized to prepare the analytes from the matrix. Chromatographic separation was carried out on a Zorbax SB C₁₈ column. The mobile phase consisted of water with 0.1% formic acid (A) and acetonitrile with 0.1% formic acid (B) at a flow rate of 0.3 mL/min. The short run time of 4 min made it possible to analyze more than 300 samples per day. The ion transitions were quantified in negative mode with multiple reaction monitoring (MRM) transitions of 347.1 → 261.1 for verinurad and 404.2 → 178.9 for the IS. The validated linear ranges of verinurad were 10-5000 ng/mL in rat plasma. The validated UHPLC-MS/MS method was further applied to the pharmacokinetic study of verinurad in rat plasma after intragastric (2 mg/kg) and intravenous (1 mg/kg) administrations. The pharmacokinetic study revealed that verinurad showed high clearance and high bioavailability (78.1%). To the best of our knowledge, this is the first report of the bioavailability study of verinurad.