Polymyxin B Sulfate

Polymyxin B Sulfate | polymyxin b sulphate | Peptide Antibiotics | Endotoxin Neutralization | Science-Peptide

Polymyxin B Sulfate is a cationic peptide antibiotic belonging to the polymyxin family. It is a potent antimicrobial and relatively toxic antibiotic with anti-endotoxin activity.Polymyxin B Sulfate neutralizes endotoxin toxicity by binding with high affinity to bacterial outer membrane lipopolysaccharides (LPS) and can be used as an adjunct to studies of Gram-negative sepsis. It has shown antibacterial activity in vitro and in vivo, with rapid bactericidal activity against multidrug-resistant Gram-negative bacteria.

Polymyxin B Sulfate, as a cationic detergent, binds to anionic lipopolysaccharides on the outer membrane of Gram-negative bacteria through electrostatic interactions, destroying the structure of the outer membrane and increasing the membrane permeability, leading to bacterial lysis and death. At the same time, it can bind to the lipid A portion of LPS to stoichiometrically neutralize the endotoxin activity, and this dual mechanism makes it uniquely valuable in antimicrobial therapy and endotoxin removal studies.

1. Synergistic antimicrobial studies with combinations of drugs
Combination therapy is an important strategy for dealing with multidrug-resistant Gram-negative bacteria.Story et al. (2025), published in Frontiers in Microbiology, showed that the combination of a peptide-neomycin coupling with Polymyxin B had a significant synergistic effect against extensively drug-resistant Acinetobacter baumannii, Klebsiella pneumoniae and Pseudomonas aeruginosa, resulting in a 2-8-fold reduction in the MIC of Polymyxin B showed a 2-8-fold reduction in MIC and no development of resistance was detected within 14 days .

2. Endotoxin neutralization and adjunctive treatment of sepsis
Polymyxin b sulphate has important applications in sepsis and endotoxemia research.Mayumi et al. (1999) reported in the journal SHOCK that a low dose of Polymyxin B (600 U/kg, intramuscularly) resulted in a 100% survival rate in CLP septic rats at 3 days (68.8% for control group), and also significantly reduced plasma It also significantly reduced plasma endotoxin levels and inhibited LPS-stimulated NO and TNF-α production. Polymyxin B-based hemoperfusion (Toraymyxin®) has been used in more than 340,000 cases globally, and PMX hemoperfusion reduced 28-day mortality from 45.1% to 38.7% and 90-day mortality from 60.8% to 43.4% in the Tigris phase III clinical trial, with a 95.3% probability of benefit post hoc.

3. Nephrotoxicity mitigation and novel formulation studies
The clinical use of Polymyxin B is limited by dose-dependent nephrotoxicity.Vishwakarma et al. (2025) reported in JAC-Antimicrobial Resistance that a novel formulation of supramolecular cation, VRP-034: in HK-2 cells with an IC₅ ₀ of 147 μg/mL (90.4 μg/mL for commercially available PMB), reduced key renal injury biomarkers by up to 70% in a 3D kidney-chip model, and reduced early renal injury markers by ≥50% in an animal model.

4. Molecular engineering modifications and imaging applications
Molecular engineering modifications have received attention to overcome toxicity limitations.Brown et al. (2020) succeeded in synthetically modifying the core of Polymyxin B cyclic peptides to obtain analogues with enhanced in vitro antibacterial activity .The 2022 Frontiers in Chemistry review systematically summarized Polymyxin B molecular engineering approaches, including Engineered molecular design for targeted imaging and therapy of bacterial infections.

• Story, S., et al. Frontiers in Microbiology, 2025, 16, 1605813.
• Mayumi, T., et al. SHOCK, 1999, 11(2), 82-86.
• Tigris phase III clinical trial data (PMX hemoperfusion).
• Vishwakarma, K., et al. JAC-Antimicrobial Resistance, 2025, 7(Supplement_4), dlaf230.110.
• Brown, P., et al. Bioorganic & Medicinal Chemistry Letters, 2020, 30(11), 127163.
• Frontiers in Chemistry, 2022, 9, 809584.

Polymyxin B Sulfate, polymyxin b sulphate, Endotoxin Neutralization, Multidrug-Resistant Gram-Negative Bacteria, Combination Synergy