[Antimicrobial and hemolytic activities of gradex]

Gradex is a polymer preparation resulting from formation of covalent bonds between the molecules of gramicidin S, a polypeptide antibiotic, and dextran, a polymeric carrier. Antimicrobial and hemolytic activities of gradex were studied. It was shown that the antimicrobial activity of gradex was due to the presence of gramicidin S in its composition. The activity level was lower than that of gramicidin S. It was also found that the gradex reduced form in concentrations up to 300 micrograms/ml had practically no hemolytic effect against human erythrocytes. The reduced form of gradex is promising for development of an artificial ++anti-brucellosis vaccine.