Several expected advantages of this approach were reported [3, 44 –46 ]: 1) the drug does not need to accumulate via the enhanced permeability and retention effect, instead it was released in the tumor vasculature and accumulates in part in endothelial cells; 2) depending on the size of the region of release and the time of activation, accumulation can be far greater than typical cancer nanotherapeutics and 3) the released drug can be rapidly internalized.
Source: wiktionary