Nanoscale polymer carriers to deliver chemotherapeutic agents to tumours.

Nanoscale polymer carriers have the potential to enhance the therapeutic efficacy of antitumour drugs as they can regulate their release, improve their stability and prolong circulation time by protecting the drug from elimination by phagocytic cells or premature degradation. Moreover, nanoscale polymeric carriers are capable of accumulating in tumour cells and tissues due to enhanced permeability and retention effect or by active targeting bearing ligands designed to recognise overexpressed tumour-associated antigens. The diversity in the polymer structures being studied as drug carriers in cancer therapy allows an optimal solution for a particular drug to be provided regarding its delivery and efficacy, and thus the patient's quality of life. This review is focused on the different types of nanoscale polymer carriers used for the delivery of chemotherapeutic agents and on the factors that affect their cellular uptake and trafficking.