- Overview
  - Polymyxin B Sulfate, USP is a polypeptide antibiotic mixture composed of Polymyxins B1, B2, and B3 fractions, with B1 and B2 fractions comprising the majority of the mixture. Polymyxin B components are structurally identical with the exception of a variable fatty acid group on each fraction. Results from in vitro studies have shown marginal differences in MIC data when comparing the fractions. Polymyxin B Sulfate is freely soluble in aqueous solution (25 mg/mL).
    Polymyxin B Sulfate, USP conforms to United States Pharmacopoeia specifications.
    
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    Background
    
    Polymyxin B targets and alters the permeability of lipopolysaccharide (LPS) found in Gram-negative bacteria leading to lysing of the cell. Polymyxin B only needs to interact with LPS, it is not required to enter the cell.
- Properties
  - CAS Number
    
    1405-20-5
    
    Molecular Formula
    
    N/A (Mixture)
    
    Molecular Weight
    
    1385.61
    
    Appearance
    
    White powder
    
    Solubility
    
    Soluble in water
    
    Other Properties
    
    Source: Bacillus polymyxa
    Assay: (Dried Basis): ≥6,000 u/mg
    Loss on Drying: ≤7.0%
    Melting Point: 217-220°C
    Purity Level: >6000 u/mg
    
    Storage
    
    2-8°C
    
    * For research use only
- Applications
  - Application Description
    
    Spectrum: Polymyxin B Sulfate targets the outer membrane of Gram-negative bacteria especially Pseudomonas aeruginosa.
    
    Microbiology Applications: Polymyxin B Sulfate is commonly used in clinical in vitro microbiological antimicrobial susceptibility tests (panels, discs, and MIC strips) against Gram-negative microbial isolates. Medical microbiologists use AST results to recommend antibiotic treatment options. Representative MIC values include:
    Pseudomonas aeruginosa 0.25 µg/mL – 1 µg/mL
    Media Supplements:
    Polymyxin B is routinely used as a selection agent in several types of isolation media:
    Perfringens agar - Supplement A and Supplement B
    Perfringens Agar - SFP and TSC Selective Supplements
    Columbia Blood Agar - Campylobacter Selective Supplement (Skirrow)
    Columbia Blood Agar - Campylobacter Selective Supplement (Blaser-Wang)
    Brucella medium - Brucella Selective Supplement
    MYP Agar - Polymyxin B Bacillus Selection Supplement
    Legionella CYE Agar - Legionella BMPA-α Selective Supplement
    Legionella CYE Agar - Legionella MWY Selective Supplement
    Campylobacter Agar - Campylobacter Selective Supplement (Preston)
    PALCAM Agar - PALCAM Selective Supplement
    Legionella CYE Agar - Legionella GVPC Selective Supplement
    m-CP Medium - Membrane C. perfringens Selective Supplement
    Burkholderia cepacia Agar Base - Burkholderia cepacia Selective Supplement
    ORSAB - ORSAB Selective Supplement
    Campylobacter Agar Base - Modified Preston Campylobacter Selective Supplement
    Brucella Medium Base - Modified Brucella Selective Supplement
    Legionella CYE Agar - Legionella GVPN Selective Supplement
    ChromogenicListeria Agar - Chromogenic Listeria Selective Supplement
    ChromogenicBacillus cereus Agar - Chromogenic Bacillus cereus Selective Supplement
    ChromogenicListeria Agar - Chromogenic Listeria Differential Supplement
    
    Plant Biology Applications: Polymyxin B Sulfate was successfully tested to counteract phytopathogenic Gram-negative bacterial growth including different strains of Pseudomonas viridiflava and Erwinia carotovora. Polymixin B Sulfate was shown to reduce bacterial growth of different strains of Pseudomonas viridiflava at low concentrations, (0.08 µg/ml) and Erwinia carotovora growth at slightly higher concentrations (0.25 µg/ml) (Selim et al. 2005). Polymyxin B has been shown to elict alkaloid accumulation in E. californica. Treatment at 0.04 mg/ml for 4 hours showed a 5.5x increase in Jasmonate levels.