# Bactericidal and virucidal action of cetylpyridinium chloride and benzocaine lozenges against common oropharyngeal pathogens

## TL;DR

This study shows that sugar-free CPC/benzocaine lozenges effectively kill viruses and bacteria linked to throat infections, offering a potential alternative to antibiotics.

## Contribution

The study demonstrates the virucidal and bactericidal efficacy of CPC/benzocaine lozenges against oropharyngeal pathogens in vitro.

## Key findings

- Lozenges showed ≥4 lg efficacy against influenza virus within 5–10 min under clean and dirty conditions.
- Bactericidal activity was observed against nine microorganisms within 5 min, with colony counts below detection limits.
- Lozenges reduced bovine coronavirus by ≥4 lg after 10 min exposure in both clean and dirty conditions.

## Abstract

Too often, antibiotics are prescribed in the treatment of pharyngitis, which can contribute to antimicrobial resistance. We aimed to assess the in vitro antiviral and antimicrobial activity of sugar-free cetylpyridinium chloride (CPC)/benzocaine lozenges, which can potentially offer a more suitable treatment for pharyngitis.

The antiviral activity of sugar-free CPC/benzocaine (1.4 mg/10 mg) lozenges (Dolo-Dobendan 1.4 mg/10 mg lozenges) was assessed using the DIN EN 14476:2019–10 suspension test against bovine coronavirus (S379 Reims) or influenza virus A (H1N1/Brisbane/59/2007) under clean and dirty conditions. Viral titers were measured after 1, 5, 10, and 30 min exposure; a reduction of ≥4 lg was considered virucidal. For bovine coronavirus, large volume plating was used due to cytotoxicity. Antimicrobial activity was measured against 11 microorganisms associated with pharyngitis, with contact times of 1, 5, and 10 min (+30 min for positive control).

For influenza, sugar-free lozenges showed ≥4 lg efficacy from 5 and 10 min exposure under clean and dirty conditions, respectively. For bovine coronavirus, sugar-free lozenges exhibited ≥4 lg efficacy at 10 min under both conditions. Bactericidal activity was observed against nine of the challenge microorganisms within 5 min, with plate counts of <10 colony-forming units (CFU)/mL for Pseudomonas aeruginosa, Staphylococcus aureus, Arcanobacterium haemolyticum, Moraxella catarrhalis, Porphyromonas gingivalis, Prevotelia intermedia, Streptococcus dysgalactiae, and Streptococcus pyogenes, and <100 CFU/mL for Streptococcus pneumoniae. Candida albicans and Escherichia coli showed counts of <10 CFU/mL at 30 min.

Sugar-free CPC/benzocaine lozenges can be recommended for uncomplicated pharyngitis and may be more appropriate than antibiotics, helping to mitigate antimicrobial resistance.