Figure 7.

CPP decorated pH-sensitive cleavable liposomes are designed and loaded with paclitaxel. The CPP (R8 peptide) is conjugated to a short PEG and long PEG chains are linked to liposomal surface by acid-sensitive hydrazone bond. Before liposomes injection, free losartan is administered to deplete the collagen I and facilitate liposomes deep penetration into tumors. Low extracellular pH in the cancer cell proximity causes long PEG detachment and exposes CPP to the tumor cell. Reprinted from reference (178) Copyright 2015, with permission from American Chemical Society