Human Serum Albumin Conjugated Nanoparticles for pH and Redox-Responsive Delivery of a Prodrug of Cisplatin.

Platinum anticancer drugs are particularly in need of controlled drug delivery because of their severe side effects. Platinum(IV) agents are designed as prodrugs to reduce the side effects of platinum(II) drugs; however, premature reduction could limit the effect as a prodrug. In this work, a highly biocompatible, pH and redox dual-responsive delivery system is prepared by using hybrid nanoparticles of human serum albumin (HSA) and calcium phosphate (CaP) for the Pt(IV) prodrug of cisplatin. This conjugate is very stable under extracellular conditions, so that it protects the platinum(IV) prodrug in HSA. Upon reaching the acidic and hypoxic environment, the platinum drug is released in its active form and is able to bind to the target DNA. The Pt-HSA/CaP hybrid inhibits the proliferation of various cancer cells more efficiently than cisplatin. Different cell cycle arrests suggest different cellular responses of the Pt(IV) prodrug in the CaP nanocarrier. Interestingly, this delivery system demonstrates enhanced cytotoxicity to tumor cells, but not to normal cells.