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A 22-residue engineered magainin that forms toroidal membrane pores against Gram-positive and Gram-negative bacteria.
Also known as: MSI-78 · pexiganan acetate
Part of the Foundational & therapeutic peptides cluster
Overview
Pexiganan (MSI-78) is a 22-amino-acid synthetic antimicrobial peptide derived from the frog-skin peptide magainin 2. It folds into an amphipathic alpha-helix on bacterial membranes and permeabilizes them through toroidal pore formation, and it has been studied as an investigational topical treatment for infected diabetic foot ulcers. This page is educational and not medical advice.
Source & context
Biological / chemical source: Synthetic analog of magainin 2 (frog-skin host-defense peptide)
Primary research or clinical context: Investigational topical agent studied for infected diabetic foot ulcers
Design and mechanism
Pexiganan was engineered from magainin 2 to increase cationic charge and helical amphipathicity. Unstructured in water, it adopts an alpha-helix on contact with anionic bacterial membranes, then inserts near the bilayer surface and induces positive-curvature strain that opens toroidal pores, dissipating membrane potential.
Research history
As a topical 1% cream it advanced through clinical trials for diabetic foot infections but did not gain U.S. regulatory approval. It remains a widely cited reference peptide in studies of membrane-active antimicrobials and structure-activity design.
Sequence
One-letter sequence commonly cited for Pexiganan (educational; isoforms and modifications may differ):
GIGKFLKKAKKFGKAFVKILKK
Residues plotted ~100° apart around an α-helix — clustering of one color reveals an amphipathic face.
Structure & chemistry
Molecular identity & reference confidence
Source-supported reference
Reference values are taken from the cited molecular record or curated profile. A database match is not independent laboratory verification; modifications, counter-ions, and formulations can change the measured mass.
- Molecular form
- Pexiganan (source record; form not independently established)
- Species
- Not established by this molecular identity audit
- Termini (N / C)
- Not specified / Not specified
Average reference mass
Reference policy updated: 2026-10-05
- IUPHAR/BPS source snapshot · 2026-10-01
- PubChem molecular record · 2026-10-01
- Molecular formula
- C122H210N32O22
- Average reference mass
- ≈ 2,477.2
- PubChem CID: 16132253
- IUPHAR ligand: 14042
- ChEMBL: CHEMBL1275802
- DrugBank: DB16293
- CAS RN: 147664-63-9
- UNII: TVF29Q70Q1
Chemistry values: PubChem, IUPHAR/BPS Guide to Pharmacology · fetched 2026-10-01.
Clinical development snapshot
ClinicalTrials.gov lists 4 registered studies with “Pexiganan” as an intervention (snapshot 2026-10-01). A registry footprint is not evidence of efficacy or approval.
| NCT | Title | Phase | Status | Updated |
|---|---|---|---|---|
| NCT00563394 | MSI-78 Topical Cream vs. Oral Ofloxacin in the Treatment of Infected Diabetic Ulcers | Phase 3 | completed | 2020-09-03 |
| NCT00563433 | MSI-78 Topical Cream vs. Oral Ofloxacin in the Treatment of Infected Diabetic Ulcers | Phase 3 | completed | 2020-09-03 |
| NCT01594762 | Pexiganan Versus Placebo Control for the Treatment of Mild Infections of Diabetic Foot Ulcers | Phase 3 | completed | 2017-06-14 |
| NCT01590758 | Pexiganan Versus Placebo Control for the Treatment of Mild Infections of Diabetic Foot Ulcers | Phase 3 | completed | 2017-06-14 |
Pexiganan — reconstitution calculator
Enter how much peptide is in the vial and how much diluent (e.g. bacteriostatic water) is added. The tool returns the resulting solution concentration — and, for any amount you type, the volume it corresponds to. This is educational arithmetic, not a dosing recommendation.
Reference form: Pexiganan (source record; form not independently established)Average reference mass: 2,477.2 Da
Enter an amount to see the volume it corresponds to.
Educational concentration mathematics only. This tool does not recommend a dose, amount, or protocol, and nothing here is medical advice. Many peptides are not authorized by Health Canada for human use — see our reconstitution and bacteriostatic-water guides for context.
FAQ about Pexiganan
What is Pexiganan?+
Pexiganan (MSI-78) is a 22-amino-acid synthetic antimicrobial peptide derived from the frog-skin peptide magainin 2. It folds into an amphipathic alpha-helix on bacterial membranes and permeabilizes them through toroidal pore formation, and it has been studied as an investigational topical treatment for infected diabetic foot ulcers. This page is educational and not medical advice.
What Canadian product status is recorded for Pexiganan?+
Canadian product status for Pexiganan has not been verified in this profile. No verified record here does not mean no authorization exists. Status depends on the product, formulation and use; consult Health Canada's product records.
What is the typical length of Pexiganan?+
Pexiganan is commonly described as approximately 22 amino acids (Synthetic antimicrobial peptide (magainin analog)).
Related peptides
References & further reading
- 1.Lamb et al. (1998). Pexiganan acetate. Drugs
- 2.Cohen et al. (2023). Interaction of Pexiganan (MSI-78)-Derived Analogues Reduces Inflammation and TLR4-Mediated Cytokine Secretion: A Comparative Study. ACS Omega
- 3.Lee et al. (2013). Lipid composition-dependent membrane fragmentation and pore-forming mechanisms of membrane disruption by pexiganan (MSI-78). Biochemistry
- 4.Ge et al. (1999). In vitro antibacterial properties of pexiganan, an analog of magainin. Antimicrob Agents Chemother
- 5.Cirioni et al. (2016). Enhanced Efficacy of Combinations of Pexiganan with Colistin Versus Acinetobacter Baumannii in Experimental Sepsis. Shock
- 6.Ge et al. (1999). In vitro susceptibility to pexiganan of bacteria isolated from infected diabetic foot ulcers. Diagn Microbiol Infect Dis
- 7.Cirioni et al. (2018). Efficacy of Pexiganan Combination with Tigecycline in a Mouse Model of Pseudomonas aeruginosa Sepsis. Curr Top Med Chem
- 8.Ghazvini et al. (2024). Sustain-release lipid-liquid crystal formulations of pexiganan against Helicobacter pylori infection: in vitro evaluation in C57BL/6 mice. BMC Pharmacol Toxicol
- 9.PubChem — compound summary for Pexiganan (CID 16132253)
- 10.PMC — Structure, membrane orientation, mechanism and function of pexiganan