Hydrophobic cavity formed by oligopeptide for doxorubicin delivery based on dendritic poly(L-lysine).

To deliver anti-cancer drugs to tumors, a hydrophobic cavity was prepared in the dendritic molecule, dendritic poly(L-lysine) of sixth generation (KG6), which was used as a drug carrier. The dendritic molecule was modified with polyethylene glycol (PEG)-linked hydrophobic penta-phenylalanine or penta-alanine. The hydrophobic cavity was formed between the KG6 and PEG chains. The penta-phenylalanine peptide was better in encapsulating doxorubicin (DOX) in the cavity compared with penta-alanine. The loaded DOX was slowly released from the cavity, and it depended on pH. After intravenous injection, the DOX-loaded dendrimers accumulated in the tumor by the enhanced permeability and retention effect, and showed significant suppression of tumor growth without loss of body weight. These results indicate that hydrophobic oligopeptides can be used for forming a hydrophobic cavity in a dendritic molecule for delivery of anti-cancer drugs to tumor sites.