A mixture of 92.4 mg (0.48 mmole) of 5-guanidino pentanamide hydrochloride, 166.5 mg (0.57 mmole) of N-[4-(3-aminopropyl)aminobutyl]-2,2-dihydroxyethanamide dihydrochloride, 62.8 mg (0.48 mmole) of glutaric acid and 0.1 ml of water was heated at 60° C. for 24 hours. After completion of the reaction, 5 ml of water was added to the reaction mixture which was then purified in a manner similar to that in Example 1, using CM-Sephadex® C-25 (Na-type) and Sephadex® LH-20 to obtain 82.5 mg (37.1% yield) of a white powder of N-[4-(3-aminopropyl)aminobutyl]-2-(5-guanidinopentanamido)-2-hydroxyethanamide trihydrochloride.
