ML133 hydrochloride is a selective K_ir2 family channels inhibitor, with an IC₅₀ of 1.8 μM at pH 7.4 and 290 nM at pH 8.5^[1]. IC50 & Target: IC50: 1.8 μM (K_ir2 at pH 7.4), 290 nM (K_ir2 at pH 8.5)^[1]. In Vitro: ML133, which inhibits K_ir2.1 with IC₅₀ of 1.8 μM at pH 7.4 and 290 nM at pH 8.5, but exhibits little selectivity against other members of K_ir2.x family channels^[1].
ML133 has no effect on K_ir1.1 (IC₅₀ > 300 μM), and displays weak activity for K_ir4.1 (76 μM) and K_ir7.1 (33 μM), making ML133 the most selective small molecule inhibitor of the Kir family reported to date^[1].