Platelet aggregation inhibiting and anticoagulant effects of oligoamines, XXIV: Interactions between oligosydnone imines and albumin or phospholipids.

Oligosydnone imines are strongly bound to albumin (alpha < 1%) in pure water. In saline, however, this effect is abolished (alpha approximately 80%). 4,4'-Propylene-bis-3-hexyl-sydnone-5-imine hydrochloride (1) moderately binds to phosphatidylcholine liposomes (PC, alpha approximately 34%). This is increased by phosphatidylethanolamine (PE). In PC/PE vesicles alpha is about 7%. The binding is further enhanced by the incorporation of negatively charged phospholipids (PL) like phosphatidylserine (PS). In PC/PE/PS liposomes complete binding of 1 can be achieved. This holds especially true if the composition of the liposomes is similar to the PL composition of platelet membranes. The results suggest that the antiplatelet activity of 1 is mediated by the bindings to negatively charged PL in the platelet membrane.