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The Sound of Evolution
Polymyxin B
Mechanism of action:
Polymyxin B is a polypeptide antibiotic. Because it is a cationic cyclic polypeptide, it can bind to lipid A in the negatively charged lipopolysaccharide (LPS) of the outer membrane of Gram-negative bacteria. This binding displaces the divalent cations (Mg²⁺ and Ca²⁺) that stabilize the lipopolysaccharide structure, leading to loosening of the outer membrane and, ultimately, bacterial lysis and death.
Reference(s):
1. Avedissian SN et al. (2019). A Review of the Clinical Pharmacokinetics of Polymyxin B. Antibiotics (Basel).
2. Nation RL et al. (2019). Polymyxin Acute Kidney Injury: Dosing and Other Strategies to Reduce Toxicity. Antibiotics (Basel).
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