Poly(ethylene glycol)-Prodrug Conjugates: Concept, Design, and Applications
Figure 6
(a) Active and passive targeting by nanocarriers [35]; (b) (1) polymer-conjugated drug is internalized by tumor cells through receptor-mediated endocytosis following ligand-receptor docking, (2) transport of DDS in membrane limited organelles; (3) fusion with lysosomes; (4) the drug will usually be released intracellularly on exposure to lysosomal enzymes or lower pH (pH 6.5–<4.0) [31]. If the drug is bound to the polymer by an acid-sensitive linker then the extracellular release of drug takes place, especially if the drug is trapped by the tumor for longer period of time.
