Overcoming multiple drug resistance in cancer using polymeric micelles.

INTRODUCTION: A major concern that limits the success of cancer chemotherapy is multidrug resistance (MDR). The drug resistance mechanisms are either host related or tumor related. The host tumor interacting factors also contribute to MDR. Multifunctional polymeric micelles offer several advantages in circumventing MDR due to their design, selectivity, and stability in cancer microenvironment. Areas covered: The review is broadly divided into two parts: the first part covers MDR and its mechanisms; the second part covers multifunctional polymeric micelles in combating MDR through its state-of-the-art design. This part covers various strategies like use of P-gp transporter inhibitors, TPGS, pH & thermo-sensitive, and siRNA for selectivity of PMs against multidrug-resistant tumors. Expert opinion: Numerous approaches have been tested using polymeric micelles to overcome MDR tumors. However, these are either limited to only in-vitro investigations and/or preliminary preclinical models and do not investigate the underlying biological mechanism. Hence, there exists an unmet need to perform fundamental research that focuses on studying the underlying mechanism and preclinical/clinical testing of the micellar formulations.