Elvax as a slow-release delivery agent for a platelet-activating factor receptor agonist and antagonist

The ability of the slow-release polymer, Elvax, to deliver a large number of different molecules to distinct brain regions has been well-documented. However, there are currently no reports of Elvax-mediated delivery of ether phospholipids, whose lipid structure renders them difficult to solubilize and detect under experimental conditions. In order to potentially examine the role of platelet-activating factor (PAF) receptors in the brain in vivo, we tested the ability of Elvax to release the ether phospholipid. PAF receptor agonist, methyl-carbamyl platelet-activating factor (mc-PAF), and the ginkolide, PAF receptor antagonist, BN 52021. Mc-PAF and BN 52021 containing Elvax sections (200 microns) prepared in methylene chloride were assayed for release characteristics with a rabbit platelet aggregation bioassay. We measured a slow, sustained release of mc-PAF and BN 52021 from Elvax in vitro over a 5 day period. Similar in vivo mc-PAF and BN 52021 release kinetics were determined. Therefore, we believe that this novel method of slow-release delivery of PAF receptor agonists and antagonists as measured with platelet aggregation is viable and offers a simple, sensitive and inexpensive method for potential in vivo studies of the roles of PAF and its receptors in neural systems.