Comparative study on the in vitro effectiveness of antithrombotic agents.

The synthetic low molecular weight inhibitors MD 805, FUT-175 and FOY as well as heparin and r-Hirudin were compared for their in vitro antithrombotic potencies and protease specificities. The amidolytic activity of thrombin and the plasma coagulation were effectively inhibited by MD 805 and, in particular, by r-Hirudin. FUT-175 and FOY revealed only weak inhibition. None of the synthetic substances discriminated between alpha-, beta- and gamma-thrombin. Beside r-Hirudin only MD 805 revealed a relatively good specificity for thrombin. On the contrary, FUT-175 and FOY are unspecific and can not be classified as thrombin inhibitors.