Abstract: Described are tripeptides or tetrapeptides comprising a proteolytic enzyme cleavable amiino acid moiety as a drug or pharmacologically active site or pharmacologically active group binding, transport by blood cells and delivery system as well as to the transport and delivery system coupled drugs. Such transport and delivery system is especially favorable for the treatment of diseases that lead to an enhanced activity of proteolytic enzymes such as cancer, arthritis, or are blood cell related.

Abstract: L-prolyl-L-m-sarcolysyl-L-p-fluorophenylalanine, lower alkyl esters and/or acid addition salts thereof are produced. For this purpose, L-p-fluorophenylalanine with a protected carboxyl group is caused to react with L-m-sarcolysine with a protected amino group preferably with cooling in an anhydrous medium in the presence of dicyclohexylcarbodiimid, L-m-sarcolysyl-L-p-fluorophenylalanine with a protected amino group and a protected carboxyl group being obtained. Then the amino protection group is removed, with formation of L-m-sarcolysyl-L-p-fluorophenylalanine with a protected carboxyl group. The obtained product is caused to react with proline with a protected amino group in the presence of dicyclohexylcarbodiimid. L-prolyl-L-m-sarcolysyl-L-p-fluorophenylalanine with a protected amino group is obtained. Finally, the amino protection group is removed, and optionally the lower alkyl ester group is removed and/or the obtained compound is converted into an acid addition salt.

Abstract: Pharmaceutical compositions are made available which serve to treat cancers, particularly melanomas.