[Transferrin conjugated PEG-liposomes as intracellular targeting carrier for tumor therapy]

For the purpose of intracellular targeting carrier by systemic administration, PEG-liposomes conjugating transferrin (TF) at the distal ends of PEG chain were newly prepared. Biodistribution of TF-PEG liposome was examined in the colon 26 bearing mice. TF-PEG liposome were prolonged in the circulation and highly accumulated into the tumor tissue. After extravasation, TF-PEG liposome retains the specific binding ability to tumor cell surface. Uptake of TF-PEG liposome was examined by electron microscopy. TF-PEG liposome was localized at the cell surface, coated pits and endosome. These results show TF-PEG liposome was bound and internalized by endocytosis. Such liposomes should be useful for intracellular targeting carrier at the way of systemic administration.