Fig. 5.

Schematic representation of peptide-functionalized PEGylated liposomes containing an active drug. Small drug molecules can efflux through the healthy blood vessels endothelial cells while the liposomal formulation remains contained in the vessel (left). In contrast, in the tumor tissue vessels (right) form large vascular fenestrae due to the rapid vascular growth which facilitate liposomal passage through the vessel and impaired lymphatic drainage helps extravasation also of large liposomal drugs. Upon accumulation, the bioactive peptide on the liposome outer layer binds to the overexpressed targeted receptor on the cancer cells, which promotes intracellular uptake through receptor-mediated endocytosis and anticancer drug accumulation in vessels or in the nucleus (Reproduced with permission from [23]).