Antiplatelet effect of the pyrimido-pyrimidinic derivative RA-642.

Amongst pyrimido-pyrimidine derivatives (p-p), dipyridamole (Dip) acts as a coronary vasodilator and platelet aggregation inhibitor (l-3), mopidamole (Mop) has been used in association with antimetastatic drugs (4,5), and RA-642 is endowed with vasodilating and hypertensive effects (6-8). We also reported that RA-642 inhibited lipid peroxidation induced by oxygen free radicals (9). We have found no references to RA-642 as a possible inhibitor of platelet aggregation. In the present study, we assessed the in vitro antiplatelet effect of RA-642 in comparison with Dip and Mop.