January 24, 2022
I’m a pretty good disinfectant, but I’m also a suspected carcinogen.
What molecule am I?
Image of Polyhexanide 3D Image of Polyhexanide

Polyhexanide [formally, poly(hexamethylene biguanide)] is an unusual water-soluble polymer with five nitrogen atoms in each repeating unit, three of them in the polymer’s backbone. It was first described in late 1960s in British, French, and South African patents to Imperial Chemical Industries (London).

Since its inception, polyhexanide and its hydrochloride salt1 have been used for a wide range of sanitizing purposes. Examples are protecting crops from molds and bacteria in the field and in storage, preserving meat and fish products, and sanitizing swimming pools. In medicine, it has been used primarily for treating keratitis (corneal infection), but also for dressing wounds.

The use of polyhexanide products may be coming to an end. In 2011, the European Chemical Agency designated it as a suspected carcinogen. Since then, its uses have been increasingly restricted in Europe. In 2017, the US Food and Drug Administration declined an application for polyhexanide as an orphan drug for keratitis.

1. CAS Reg. No. 32289-58-0.

Polyhexanide hazard information*

Hazard class**GHS code and hazard statement
Skin sensitization, category 1H317—May cause an allergic skin reactionChemical Safety Warning
Serious eye damage/eye irritation, category 1H318—Causes serious eye damage Chemical Safety Warning

Acute toxicity, inhalation, category 3

H331—Toxic if inhaledChemical Safety Warning
Carcinogenicity, category 2H351—Suspected of causing cancerChemical Safety Warning
Specific target organ toxicity, repeated exposure, inhalation, category 1H372—Causes damage to organs through prolonged or repeated exposure if inhaledChemical Safety Warning

*Information for 20 wt% aqueous solution. 
**Globally Harmonized System (GHS) of Classification and Labeling of Chemicals. Explanation of pictograms.

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Polyhexanide fast facts

CAS Reg. No.28757-47-3
Poly(iminocarbonimi- doylimino- carbonimi- doylimino-1,6-hexanediyl)
Empirical formula(C8H17N5)n
Molar massVariable
AppearanceWhite to pale yellow solid
Melting pointVariable
Water solubility≈400 g/L
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Learn more about this molecule from CAS, the most authoritative and comprehensive source for chemical information.

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