Polyhexamethylene guanidine-commonly encountered in the form of polyhexamethylene guanidine hydrochloride (PHMG or PHMB)-is a polymeric biocide widely utilized in fields such as disinfection and antimicrobial applications. It exhibits broad-spectrum antimicrobial activity, effectively combating a diverse range of bacteria and fungi. Its mechanism of action is predicated on the activity of its guanidine groups, which impart a positive charge to the polymer; this positive charge facilitates the adsorption of microorganisms-which typically carry a negative charge-thereby inhibiting their cellular division.
Toxicological studies indicate that the acute oral LD50 in mice exceeds 5000 mg/kg, classifying the substance as practically non-toxic, and it demonstrates no irritant effects on the skin. However, studies simulating inhalation exposure have suggested that subchronic exposure to PHMG may pose potential risks of respiratory toxicity.
