Antibiotic with bactericidal action on E. coli. Binds to the lipid A portion of bacterial lipopolysaccharides. Induces pore formation in the membranes of cortex cells from excised sorghum roots. Mixture of Polymyxin B1 and B2 sulfate.Biological potency (dry basis): >6000U/mg.Form:White SolidMelting Point:217-220°C (dec.)Solubility:Water