Hexetidine

Hexetidine (CAS No. 141-94-6) is a broad-spectrum antimicrobial agent whose core biological activity is to inhibit the growth of Gram-positive bacteria, Gram-negative bacteria, and fungi (such as Candida albicans). It does not have a clearly defined single molecular target; its activity is presumed to be mediated by disrupting microbial cell membrane integrity and interfering with metabolism. Hexetidine shows no inhibitory activity against the SARS-CoV-2 proteases 3CLpro and PLpro. MIC values are strain-specific: in planktonic form, 0.02 mg/mL for Staphylococcus aureus, 0.25 mg/mL for Pseudomonas aeruginosa, 10–12.5 μg/mL for Streptococcus mutans, 100–125 μg/mL for Escherichia coli, and 14.3–20 μg/mL for Candida albicans. When combined with copper ions, the MIC against oral streptococci can be reduced to 1.2×10?3~1.8×10?3 mM (synergistic effect). In biofilm form (24 h), the MBC for Staphylococcus aureus is 0.5 mg/mL and for Pseudomonas aeruginosa is > 0.5 mg/mL. Common application concentrations include 0.02–125 μg/mL (gradient concentrations) for in vitro antimicrobial testing, 1 mg/mL for 4 h in biofilm inhibition assays, and 0.1%–0.2% in mouthwashes for animal and preclinical studies. The clinically effective therapeutic concentration corresponds to a 0.1% (1 mg/mL) mouthwash, used by adults 2–3 times daily, rinsing for 30 seconds to 1 minute each time, which can reduce dental plaque and alleviate gingivitis, and is suitable for oral infections (such as aphthous ulcers and halitosis). Higher concentrations (0.14% and above) are more likely to cause mucosal irritation and other side effects and are not suitable for routine use. Its residual antibacterial activity in saliva can last for 3 hours, with oral bacterial counts gradually recovering after 90 minutes.

References:

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