Synthesis and antitumor activities of amino acid prodrugs of amino-combretastatins.

The synthesis and antitumor activity of water-soluble amino acid prodrugs of amino-combretastatins were reported. Among the synthesized compounds, 7e (CS-39-L-Ser HCI, AC-7700) showed enhanced antitumor activity and decreased toxicity in a Colon 26 murine adenocarcinoma model. Compound 7e showed improved solubility and was easily formulated for in vivo administration. Compound 7e was cleaved to generate the parent compound, CS-39, in the whole blood of mice as well as man, possibly by the action of amino peptidase on the erythrocyte membrane.