an oral prostacyclin receptor (IP receptor) agonist that is structurally distinct from prostacyclin, indicated for the treatment of pulmonary arterial hypertension, selexipag is hydrolyzed by carboxylesterase 1 to yield its active metabolite, which is approximately 37-fold as potent as selexipag, selexipag and the active metabolite are selective for the IP receptor versus other prostanoid receptors (EP1-4, DP, FP and TP)