Colistin sulfate

Ph. Eur. Peptide antibiotic. Mixture of the sulfates of polypeptides produced by certain strains of Bacillus polymyxa var. colistinus. Acts mainly against Gram-negative bacteria. Causes changes in membrane structure resulting in leakage of small molecules. Soluble in water; stable between pH 2 - 6 at 4 °C. Protect from light.