Antimicrobial and Antiviral Effects of Viscous Mouthwash Containing Cetylpyridinium Chloride and Isopropyl Methylphenol.

OBJECTIVES: To evaluate the antimicrobial and antiviral activities of a viscous mouthwash containing cetylpyridinium chloride (CPC) and isopropyl methylphenol (IPMP). METHODS: An experimental mouthwash containing 0.05% CPC, 0.1% IPMP, and 0.3% hydroxyethyl cellulose was compared with commercially available mouthwashes. Antibacterial and fungicidal activities were quantified as log10 reductions in viable cell counts following 10-30 s (bacteria) or 10-20 min (fungi) of exposure. Antiviral activity against influenza A virus (H3N2) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant was evaluated using ASTM E1052-20 suspension assays. RESULTS: The CPC-IPMP mouthwash exhibited rapid bactericidal activity (≥3 log10 reduction) against all tested bacterial species within 20-30 s and showed near-complete killing of Candida albicans within 10-20 min. Antiviral testing demonstrated measurable virucidal activity, reducing viral titres by 1.3 log10 PFU/mL for H3N2 and 1.8 log10 PFU/mL for SARS-CoV-2 Omicron after 20 s of exposure. CONCLUSIONS: The viscous CPC-IPMP mouthwash demonstrated potent antimicrobial activity against oral bacteria and Candida albicans, together with measurable antiviral activity against influenza A virus and SARS-CoV-2. Further in vivo and clinical studies are required to determine the clinical relevance and effectiveness of this formulation. CLINICAL SIGNIFICANCE: The CPC-IPMP mouthwash may serve as a useful adjunctive oral hygiene measure for reducing oral microbial and viral burdens.