ABSTRACT
The encapsulation of pharmacologically active compounds in erythrocytes is an attractive alternative to microvesicle systems such as liposomes or synthetic microcapsules. Amphotericin B, a polyene antibiotic, was used to encapsulate daunomycin in mouse erythrocytes. Polyene antibiotics have the general property of increasing membrane permeability which is the basis of the antibiotic action. The daunomycin loaded erythrocytes were successfully used to treat leukemic mice. Erythrocytes possess the essential property of deformability which allows them easy access through narrow blood vessels. The normal aged, altered, or damaged erythrocytes are eliminated from the circulation primarily by phagocytosis followed by intracellular digestion of the erythrocyte matrix and hemoglobin. Cold storage of erythrocytes may also result in irreversible changes in the membrane, lipid loss, and conformational movements of the protein, all of which result in increased osmotic fragility and decreased deformability of the cells. A reduction in deformability of erythrocytes might account in part for the high splenic localization.
