Interaction of Oxygen Carrying Microparticles with Blood Components and Clearance from Blood Stream

Abstract

The stable microparticles (polymeric liposomes) having a synthetic heme-imidazole complex and carrying oxygen were studied in the interaction with blood components in vitro. They did not induce hemolysis, platelet aggregation and plasma coagulation directly and were stable against the hydrolysis by phospholipases. Intravenous injection of the 14C-labeled particles into rats indicated the half-disappearance time from the blood stream of ca. 14 hr. Their tissue distribution was analyzed with time by autoradiography.

The authors have demonstrated that a stable synthetic oxygen carrier can be prepared by embedding a synthetic heme complex into the hydrophobic region of lipid bilayers of liposomes (1–4). By the use of polymeric liposomes (5), we have succeeded in preparing a stable solution of high heme concentration (6). The new oxygen-carrying aqueous solution had physical properties similar to those of whole blood. To elucidate the further possibility of the micro-particles as red blood cell models, the interaction with blood components in vitro and the behavior in the circulation in vivo are described in this communication.