Novel and emerging approaches for the delivery of metallo-drugs

Cisplatin and its derivatives are the most widely used clinical anticancer agents. They bring enormous benefits to patients but are also associated with unpleasant side-effects because of their abilities to interact with biomolecules other than the target DNA and their broad tissue toxicity across the body. While two molecular re-designs of cisplatin have entered worldwide clinical use (carboplatin and oxaliplatin) and many more have been trialled, these side effects and drawbacks remain. Recently new strategies have been developed to attempt to decrease these side effects and/or modify the tissue activity spectrum through more localized and effective delivery of the drug to the desired targets. In this review we present an overview of the principal approaches that have been explored, ranging from conjugation to biomolecular vectors or polymers, through pro-drug strategies, to adsorption on ceramic materials and encapsulation in macrocycles, nanotubes and nanocapsules, biomolecules and polymers.