Description:

IC50: 2.7 μM

Plasminogen activator inhibitor-1 (PAI-1) is the most important physiologic regulator of the plasminogen activation system through its inhibition of its target serine proteases, tissue plasminogen activator, and urokinase plasminogen activator. Significant elevations of PAI-1 lead to stabilization of arterial and venous thrombi, which contribute respectively to coronary arterial occlusion in postmyocardial infarction and venous thrombosis following postoperative recovery from orthopedic surgery. Tiplaxtinin (PAI-039) is a novel, orally efficacious inhibitor of PAI-1.

In vitro: Tiplaxtinin inhibited PAI-1 as determined by the antibody method. By use of fluorescent spectroscopy, tiplaxtinin bound to the PAI-1 mutant selectively with a Kd of 480 nM. This binding event was saturable and associated with inhibition of the protein [1].

In vivo: In the rat model of carotid thrombosis, oral administration of tiplaxtinin at 1 mg/kg increased time to occlusion and prevented the carotid blood flow reduction when compared to the vehicle group. All of the vehicle control rats exhibited thrombosis with an average time to occlusion of 11 min and a complete reduction of 100% carotid flow. Conversely, those rats receiving tiplaxtinin at 1 mg/kg po exhibited an average time to occlusion of >50 min and a carotid blood flow reduction of approximately 50% [1].

Clinical trial: Up to now, tiplaxtinin is still in the preclinical development stage.

Reference:
[1] Elokdah H, Abou-Gharbia M, Hennan JK, McFarlane G, Mugford CP, Krishnamurthy G, Crandall DL.  Tiplaxtinin, a novel, orally efficacious inhibitor of plasminogen activator inhibitor-1: design, synthesis, and preclinical characterization. J Med Chem. 2004 Jul 1;47(14):3491-4.