hURAT1 inhibitor 1 (compound 27b) is an isomarine-based, orally active dual hURAT1/GLUT9 inhibitor with IC 50 s of 0.16 μM and 4.47 μM, respectively, and has anti-hyperuricemia effects. hURAT1 inhibitor 1 showed significant uric acid-lowering activity in a hyperuricemia mouse model (10 mg/kg dose). hURAT1 inhibitor 1 had no significant in vitro cytotoxicity or in vivo hepatotoxicity and showed good PK characteristics.