Preclinical and clinical studies of anticancer agent‐incorporating polymer micelles

Abstract

The size of anticancer agent‐incorporating micelles can be controlled within the diameter range of 20–100 nm to ensure that they do not penetrate normal vessel walls. With this development, it is expected that the incidence of drug‐induced side‐effects may be decreased owing to the reduced drug distribution in normal tissue. Micelle systems can also evade non‐specific capture by the reticuloendothelial system because the outer shell of a micelle is covered with polyethylene glycol. Consequently, a polymer micelle carrier can be delivered selectively to a tumor by utilizing the enhanced permeability and retention effect. Moreover, a water‐insoluble drug can be incorporated into polymer micelles. Presently, several anticancer agent‐incorporating micelle carrier systems are under preclinical and clinical evaluation. Furthermore, nucleic acid‐incorporating micelle carrier systems are also being developed. (Cancer Sci 2009; 100: 572–579)