Studies on Tumor Selective Targeting by Temperature-Sensitive Liposomes Encapsulated Doxorubicin with Local Hyperthermia.

Tissue distribution and tumor uptake of temperature-sensitive liposomes entrapping doxorubicin (DXR) with local hyperthermia were studied. The liposomes composed of dipalmitoylphosphatidylcholine and distearoylphosphatidylcholine (9: 1, molar ratio) were prepared by reverse-phase evaporation method expecting to release the drug at 41°C by hyperthermia. The liposomes were injected intravenously via the tail vein into BALB/c mice bearing tumors (colon carcinomas 26) implanted in hind foot, and local hyperthermia at 42°C was applied for 20 minutes. Liposomal DXR accumulated in reticuloendothelial system such as liver and spleen, but this uptake was decreased with local hyperthermia. The tumor uptake of liposomal DXR with local hyperthermia was 4 times larger than that of free drug. These results suggest that this thermochemotherapy will be useful for targeting therapy.