PEGylated lysine dendrimers for tumor-selective targeting after intravenous injection in tumor-bearing mice.

In this study, we synthesized a sixth generation lysine dendrimer (KG6) and two PEGylated derivatives thereof and evaluated their biodistribution characteristics in both normal and tumor-bearing mice. The intact KG6 showed a rapid clearance from the blood stream and non-specific accumulation in the liver and kidney. In contrast, the PEGylated derivatives showed a better retention in blood and low accumulativeness in organs dependent of the rate of PEGylation. In addition, PEGylated KG6 with a high modification rate was accumulated effectively in tumor tissue via the enhanced permeability and retention (EPR) effect. Moreover, we clarified that multiple administrations did not affect the biodistribution characteristics of a second dose of PEGylated KG6. PEGylated lysine dendrimer would be a useful material for a clinically applicable tumor-targeting carrier.