β-Cyclodextrin/epoxysuccinyl peptide conjugates: a new drug targeting system for tumor cells

β-Cyclodextrin is known to form inclusion complexes with hydrophobic drugs. Several tumor cell lines are known to secrete and/or contain membrane-associated cathepsin B which is possibly involved in invasion and metastasis. Based on these informations, our recently developed endo-epoxysuccinyl peptide inhibitor MeO-Gly-Gly-Leu-(2S,3S)-tEps-Leu-Pro-OH for cathepsin B was conjugated with β-cyclodextrin to obtain a site-directed drug carrier system. Furthermore, the conjugate was shown to form an inclusion complex with the cytotoxic drug methotrexate.