Colistin sulfate (USP Grade)

Very potent polymyxin antibiotic - Has only one amino acid difference compared to polymyxin B - Antimicrobial - Targets the lipopolysaccharide (LPS) of the outer membrane of Gram-negative bacteria. Competitively displaces divalent cations (Ca2 and Mg2) from the negatively-charged phosphate groups LPS, causing disruption of the membrane. This increases the permeability of the cell envelope, leakage of cell contents, leading to apoptosis and cell death - Used against multidrug-resistant Gram-negative bacterial infections.