[Basic study and application of functional liposomes].

Liposomes are the models of biomembranes and are new thought to be ideal tools in the field of drug delivery system. Liposomalization of various drugs has been revealed to enhance their efficacy and to reduce the side effect of the drugs. For the site-specific delivery, intracellular targeting, and controlled release of drugs, many functional liposomes have been developed based on their natures as the models of biomembranes. In this report, the preparation and characterization of functional liposomes are discussed. At first, the hydration process of lipids which is an important step for the liposomal preparation was discussed. Secondly, three kinds of functional liposomes were presented, namely, thermosensitive liposomes for delivering macromolecules, pH-sensitive liposomes for the cytosolic delivery of encapsulated materials, and reticuloendothelial system (RES)-avoiding liposomes for the passive targeting to tumor tissues. Finally, the actual usefulness of RES-avoiding liposomes modified with a uronic acid derivative, palmityl-D-glucuronide for the tumor imaging and therapy was demonstrated.