EPR effect based nanocarriers targeting for treatment of cancer

Abstract

The enhanced permeability and retention (EPR) effect is a unique phenomenon of solid tumors related to their anatomical and pathophysiological differences from normal tissues. In solid tumors, angiogenesis leads to high vascular density. Large gaps exist between endothelial cells in tumor blood vessels, which lead to selective extravasations and retention of macromolecular drugs. This EPR effect served as a basis for development of macromolecular anticancer therapy. There are various factors, which lead to a significantly increased EPR effect and enhanced antitumor drug effects as well. This review discusses the unique anatomy of tumor vessels, molecular mechanisms of factors related to the EPR effect and the role of the EPR effect in the intratumoral delivery of protein and peptide drugs, macromolecular drugs and drug-loaded long-circulating nanocarriers.