Development of boron nanocapsules for neutron capture therapy

High accumulation and selective delivery of boron into tumor tissues are the most important requirements to achieve efficient neutron capture therapy of cancers. We focused on liposomal boron delivery system in order to achieve a large amount of boron delivery to tumor. We synthesized the double-tailed boron cluster lipid 4c according to our reported procedure with modification. Size distribution of liposomes prepared from the boron cluster lipid 4c, DMPC, PEG-DSPE, and cholesterol was determined as 100 nm in diameter by an electrophoretic light scattering spectrophotometer. A high level of 10B concentration (22 ppm) was observed in tumor tissue at 24 h after the administration of boron liposomes.