Nanotechnologies to use bisphosphonates as potent anticancer agents: the effects of zoledronic acid encapsulated into liposomes

Treatment failure with zoledronic acid (ZOL) is likely based on the almost exclusive localization and distribution of this agent in bone tissues, above all in the "osteoclastic niche." PC3 xenografts showed a resistance to ZOL treatment having only about 16%-22% of tumour growth inhibition (Table on the right) after 10 or 20 total μg ZOL treatment. On the contrary, 10 or 20 total μg LipoZOL-PEG20 induced a 58-68% of tumour growth inhibition (Table on the left). Therefore, the encapsulation of ZOL in PEGylated liposomes that escape from reticuloendothelial system sensitized PC3 cells to the anti-tumour activity of ZOL. The delivery of ZOL in liposomes overcomes the bioavailability limitations of ZOL allowing it to reach the "tumour niche."170