Ex vivo anti-platelet effects of isocarbacyclin methyl ester incorporated in lipid microspheres in rabbits.

Effect of TTC-909, a chemically stable isocarbacyclin methyl ester (CAS 88931-51-5, TEI-9090) incorporated in lipid microspheres, on platelet aggregation was tested in conscious rabbits. TTC-909 significantly inhibited platelet aggregation induced by ADP at early times after bolus i.v. injection from the dose of 0.3 micrograms/kg in a dose-dependent manner. Similarly, TTC-909 significantly inhibited platelet aggregation induced by ADP during the venous infusion from the dose of 100 ng/kg/min, also in a dose-dependent manner. The anti-platelet effect of TTC-909 was observed at a dose lower than that inducing hypotensive effect when given as both bolus i.v. and venous infusion. On the other hand, prostaglandin (PG) E1 (LM)--PGE1 incorporated in lipid microspheres--reduced blood pressure without having an anti-platelet effect. These results indicate that TTC-909 may be a potent anti-thrombotic drug.