Recent Advances in the Local Drug Delivery Systems for Improvement of Anticancer Therapy.

The conventional anticancer chemotherapies not only cause serious toxic effects but also produce resistance in tumor cells exposed to long-term therapy. Usually, the selective killing of metastasized cancer cells requires long-term therapy with higher drug doses because the cancer cells develop resistance due to the induction of poly-glycoproteins (P-gps) that act as a transmembrane efflux pump to transport drugs out of the cells. During the last few decades, scientists have been exploring new anticancer drug delivery systems such as microencapsulation, hydrogels, and nanotubes to improve bioavailability, reduce drug-dose requirement, decrease multiple drug resistance, and save normal cells as non-specific targets.