The antiplatelet activity of immobilized prostacyclin.

Owing to the chemical instability of prostacyclin, the direct immobilization of this prostaglandin has not been successful. A new procedure is described for the preparation of immobilized prostacyclin based on the conversion of immobilized prostaglandin F2 alpha to immobilized prostaglandin I2-Materials thus prepared show dramatic antiplatelet effects with regard to platelet aggregation and platelet adhesion. Radioimmunoassays of plasmas used in in vitro platelet tests and of buffers used in prostacyclin leakage studies established that these effects are not due to the release of prostacyclin from the respective immobilization substrates.