High affinity, non-peptide antagonist of the urotensin-II (UT) receptor. Exhibits high affinity for mammalian UT receptors, including human, mouse and rat (Ki values are 9.3, 19.1 and 20.7 nM respectively, in HEK293 cells expressing recombinant UT receptors). Also inhibits binding of radiolabeled urotensin to endogenous human UT receptors (Ki = 5.4 nM in a whole-cell binding assay). Displays ≥100-fold selectivity for the human UT receptor over 86 different receptors, ion channels, enzymes, transporters and nuclear hormones. Purity 98%. MW (observed): 539.36