Identification of Human UDP-Glucuronosyltransferase and Sulfotransferase as Responsible for the Metabolism of Dotinurad, a Novel Selective Urate Reabsorption Inhibitor

Dotinurad, a novel selective urate reabsorption inhibitor, is used to treat hyperuricemia. In humans, orally administered dotinurad is excreted mainly as glucuronide and sulfate conjugates in urine. To identify the isoforms of UDP-glucuronosyltransferase (UGT) and sulfotransferase (SULT) involved in dotinurad glucuronidation and sulfation, microsome and cytosol fractions of liver, intestine, kidney, and lung tissues (cytosol only) were analyzed along with recombinant human UGT and SULT isoforms. Dotinurad was mainly metabolized to its glucuronide conjugate by human liver microsomes (HLMs), and the glucuronidation followed the two-enzyme Michaelis-Menten equation. Among the recombinant human UGT isoforms expressed in the liver, UGT1A1, UGT1A3, UGT1A9, and UGT2B7 catalyzed dotinurad glucuronidation. Based on inhibition analysis using HLMs, bilirubin, imipramine, and diflunisal decreased glucuronosyltransferase activities by 45.5%, 22.3%, and 22.2%, respectively. Diflunisal and 30-azido-30-deoxythymidine, in the presence of 1% bovine serum albumin, decreased glucuronosyltransferase activities by 21.1% and 13.4%, respectively. Dotinurad was metabolized to its sulfate conjugate by human liver cytosol (HLC) and human intestinal cytosol (HIC) samples, with the sulfation reaction in HLC samples following the two-enzyme Michaelis-Menten equation and that in HIC samples following the Michaelis-Menten equation. All eight recombinant human SULT isoforms used herein catalyzed dotinurad sulfation. Gavestinel decreased sulfotransferase activity by 15.3% in HLC samples, and salbutamol decreased sulfotransferase activity by 68.4% in HIC samples. These results suggest that dotinurad glucuronidation is catalyzed mainly by UGT1A1, UGT1A3, UGT1A9, and UGT2B7, whereas its sulfation is catalyzed by many SULT isoforms, including SULT1B1 and SULT1A3. SIGNIFICANCE STATEMENT The identification of enzymes involved in drug metabolism is important to predicting drug-drug interactions (DDIs) and interindividual variability for safe drug use. The present study revealed that dotinurad glucuronidation is catalyzed mainly by UGT1A1, UGT1A3, UGT1A9, and UGT2B7 and that its sulfation is catalyzed by many SULT isoforms, including SULT1B1 and SULT1A3. Therefore, dotinurad, a selective urate reabsorption inhibitor, is considered safe for use with a small risk of DDIs and low interindividual variability.