Ex‐vivo and In‐vivo Antithrombotic Effect of Triflavin, an RGD‐containing Peptide

Abstract— Triflavin, an Arg‐Gly‐Asp‐containing snake venom peptide, inhibits platelet aggregation through the blockade of fibrinogen binding to the activated platelets. It binds to fibrinogen receptors associated with the glycoprotein IIb/IIIa complex with a K_d value of 7 × 10⁻⁸ m. In this study, we found that ¹²⁵I‐triflavin reached the maximal binding to human platelets within 5 min at 25°C. In addition, when triflavin was intravenously administered at 1·0 mg kg⁻¹ to rabbits, it reversibly impaired the platelet aggregation of platelet‐rich plasma caused by ADP (20 μm) ex‐vivo over 30 min. The platelet counts of the experimental rabbits remained unchanged. Triflavin was effective in reducing the mortality of ADP‐induced acute pulmonary thromboembolism in mice when administered intravenously at a dose of 2 μg g⁻¹. Therefore, triflavin was proven to be an effective antithrombotic agent in preventing ADP‐induced acute pulmonary thromboembolism in mice and impairing reversibly the platelet function of rabbits when given intravenously. 1994 Royal Pharmaceutical Society of Great Britain