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Chalet TanDr. Chalet Tan is an Associate Professor in the Department of Pharmaceutical Sciences at Mercer University College of Pharmacy, Atlanta, GA.

Conventional anticancer drugs are notoriously toxic to normal organs. In addition to killing the proliferating tumor cells, treatment of cancer patients with chemotherapeutic agents is commonly associated with debilitating side effects such as bone marrow suppression and toxicities towards major organs like the liver, small intestine, and kidney. To further exacerbate the toxicities, many of these anticancer drugs have very limited aqueous solubility, which necessitates the use of a large volume of toxic organic solvents and surfactants. One of the primary goals of cancer nanomedicine is to devise nano-sized drug delivery systems to improve the biopharmaceutical properties of anticancer drugs so that the efficacy and safety of this important class of drugs could be enhanced in cancer patients.

Among the various types of nanosystems that are under intense investigation, polymeric micelles are regarded as promising nanocarriers for the delivery of anticancer drugs. Self-assembled from biodegradable and biocompatible amphiphilic block polymers, and with sizes ranging from 10 to 200 nm, polymeric micelles have the capacity to solubilize clinically relevant doses of water-insoluble drugs without the inclusion of any organic excipients. Moreover, drug-loaded polymeric micelles can preferentially accumulate in the tumor via the enhanced permeability and retention effect, leading to elevated drug exposure in the tumor without increasing the drug levels in normal organs.

Polymeric Micelle

Figure 1: Schematic of multiple anticancer drugs loaded in a polymeric micelle

A team at Mercer University recently demonstrated that polymeric micelles can concurrently deliver multiple anticancer drugs with improved pharmacokinetics and anticancer efficacy in tumor-bearing mice, thereby facilitating increased patient compliance. In the future, use of active targeting strategy by incorporating tumor targeting ligands such as folic acid, cyclic RGD and transferrin can further increase the efficacy of anticancer drugs.

Recently, several nanocarrier based chemotherapeutic drugs are being approved for use in humans. Nevertheless, commercialization of nanotechnology-based drugs is faced with numerous challenges.

What challenges do you foresee in translating the exciting findings from research lab into the clinic?