MECHANISTIC STUDY ON TOXICITY OF POSITIVELY CHARGED LIPOSOMES CONTAINING STEARYLAMINE TO BLOOD

We studied the interaction of stearylamine (SA) containing liposomes ( SA-liposomes) with erythrocyte ghost (EG) or platelets, utilizing the Tb/dipicolinate (Tb/DPA) assay for the mixing of aqueous contents and a resonance energy transfer (RET) assay for the mixing of lipid. The r esults demonstrate that SA-liposomes and EG, after aggregation, have a great tendency to mix their lipid before the mixing of the internal c ontents. The mixing of their contents takes place inside the vesicles due to the fusion of SA-liposomes and EG, followed by the leakage of t he contents from the vesicles. In the presence of carboxymethyl chitin (CM-chitin), SA-liposomes-EG interaction was inhibited indicating tha t CM-chitin reduces the tendency bf SA-liposomes to interact with EG. The lipid mixing between SA-liposomes and platelets was not affected b y CM-chitin or phagocytosis inhibitors: EDTA, cytochalasin B, or 2,4-d initrophenol and iodoacetate, indicating the importance of glycoprotei ns on the platelet membrane surface in the interaction of SA-liposomes with platelets.