Among the P2Y13 receptor antagonists, there are some nonselective P2Y12/13 antagonist including a highly potent P2Y12 antagonist AR-C69931 (IC50 = 0.4 nM) and 2-MeSAMP.221 However, nonnucleoside MRS-2211 is a selective antagonist of P2Y13 and displays high selectivity over P2Y1 and P2Y12 receptors.307