Aprocitentan D4 (ACT-132577 D4) is a deuterium labeled Aprocitentan. Aprocitentan is a major and pharmacologically active metabolite of Macitentan. Aprocitentan is dual ETA/ETB antagonist with IC50s of 3.4 nM and 987 nM, and pA2 valus of 6.7 and 5.5, respectively[1].
[1]. Iglarz M, et al. Pharmacology of macitentan, an orally active tissue-targeting dual endothelin receptor antagonist. J Pharmacol Exp Ther. 2008 Dec;327(3):736-45.