Tumor targeting based on the effect of enhanced permeability and retention (EPR) and the mechanism of receptor-mediated endocytosis (RME).

This review is focused on the macromolecular drug carrier systems by the effect of enhanced permeability and retention (EPR) and the mechanism of receptor-mediated endocytosis (RME). The effect of EPR is thought to be useful for the targeting of the macromolecular drugs to the tumor tissues on a vasculolymphatic level. The RME reveals the selective recognition, high affinity binding, and immediate internalization for the ligand on a cellular level. In the receptor, recognizing transferrin, a level of expression on the tumor cells is higher than that on the normal cells. We have used serum albumin and transferrin as drug carriers to deliver mitomycin C (MMC) to the tumor tissues and into the tumor cells. The properties of the conjugates of MMC to serum albumin and transferrin were examined in vitro and in vivo. We concluded that MMC could be delivered to the tumor tissue and cells by the use of albumin and transferrin as drug carriers.