AR-H067637 is a rapid-binding, reversible and potent (inhibition constant K(i) = 2-4 nM), competitive inhibitor of thrombin, as well as of thrombin bound to fibrin (clot-bound thrombin) or to thrombomodulin. The total amount of free thrombin generated in platelet-poor clotting plasma was inhibited concentration-dependently by AR-H067637, with a concentration giving half maximal inhibition (IC(50)) of 0.6 microM. AR-H067637 also inhibited thrombin-induced platelet activation (by glycoprotein IIb/IIIa exposure, IC(50) 8.4 nM) and aggregation (IC(50) 0.9 nM).
