Folate receptor-targeted hybrid lipid-core nanocapsules for sequential delivery of doxorubicin and tanespimycin.

When exposed to cancer cells, cytotoxic drugs such as doxorubicin (DOX) can lead to the induction of heat shock protein 90 (Hsp90), a molecular chaperone associated with a number of cancer-related client proteins, and result in cell survival. Co-administration of DOX with tanespimycin (TNP), an Hsp90 inhibitor, can sensitize the cancer cells to the cytotoxic effects of DOX. The effect of such a combination has been found to depend on the schedule of administration. Sequential administration of DOX and TNP has been linked to highly synergistic combination effects. Therefore, we aimed to develop folate-receptor targeted hybrid lipid-core nanocapsules comprising a hybrid lipid core lodging TNP and a polymeric corona lodging DOX (F-DTN). These nanocarriers were capable of delivering DOX and TNP sequentially, which was well demonstrated by an in vitro release study. The in vitro release profiles displayed pH-dependent and sustained release features. F-DTN exhibited excellent morphological characteristics with highly monodispersed particles. In vitro tests with F-DTN in MCF-7 cell line demonstrated exceptional cytotoxicity, with high cellular uptake and apoptosis. These findings were appreciably more assertive than tests with free individual drugs (DOX, TNP), free drug combination (DOX/TNP), or non-folate receptor-targeted hybrid lipid-core nanocapsules (DTN). In vivo pharmacokinetic study revealed noticeable enhancement of bioavailability and plasma circulation time of the drugs when encapsulated in the carrier system. Therefore, hybrid lipid-core nanocapsules have the potential to be utilized for application in folate receptor-targeted combination chemotherapy.