Morphological observations on the cellular and subcellular destination of intravenously administered liposomes.

The cellular and subcellular fate of intravenously administered liposomes was traced by light and electron microscopy, using nitroblue tetrazolium (NBT) as a marker. Liposomes were found almost exclusively within phagocytic vacuoles of cells of the reticuloendothelial system. Fusion of lysosomes with phagocytic vacuoles and liposomal degradation were clearly visible. Liposomes may find wide application in the study and treatment of metabolic, infectious and neoplastic disease of phagocytic cells.