Phase separation in phosphatidylcholine bilayers as a predictor of inhibition of blood platelet aggregation by amantadines.

The ability of eleven amantadine derivatives to induce phase separation in dipalmitoyl phosphatidylcholine bilayers was studied by differential scanning calorimetry. The relative potency varied with the shape and size of the hydrocarbon cage. These agents also markedly inhibited blood platelet aggregation. The relative potencies of these compounds to induce phase separation showed a significant correlation (r = 0.70) with their platelet inhibitory activity suggesting that their pharmacologic action may be at the level of the platelet membrane. The effective concentration of the parent component amantadine is similar to its pharmacologic concentration suggesting its use as an anti-platelet drug.