Polymyxin B are antibiotics primarily used for resistant gram negative infections. Polymyxins bind to the cell membrane and alters its structure making it more permeable. The resulting water uptake leads to cell death. They are cationic, basic proteins that act like detergents. Side effects include neurotoxicity and acute renal tubular necrosis.
Mechanism of action
Alters cytoplasmic membrane permeability by binding to a negatively charged site in the lipopolysaccharide layer which has an electrostatic attraction for the positively charged amino groups in the cyclic peptide portion
Fatty acid portion dissolves in hydrophobic region of membrane and disrupts membrane integrity.
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