MK0524, a fused indole-based antagonist of prostaglandin D2 (DP), has a Ki binding affinity of 0.57 nM and a Kd dissociation constant of 0.03 nM. With the exception of the TxA2 receptor (Ki = 2.95 nM), MK0524 has excellent selectivity over a number of other prostanoid receptors (EP family, FP, and IP). In a functional activity assay in platelet-rich plasma and washed platelets, MK0524 had an IC50 of 0.09 nM. [1]

MK-0524 has been shown to block nicotinic acid-induced cutaneous vasodilation and also antagonizes prostaglandin D1 (DP1) in a mouse DP1 functional assay at an IC50 of 1.1 nM. [2]