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The pharmacokinetics of hexylresorcinol-containing lozenges and their antimicrobial efficacy against oral and respiratory microorganisms

Priyanka Sharma Orcid Logo, Charlotte Richards Orcid Logo, Jennifer Y. M. Adams Orcid Logo, Kirsten Bentley Orcid Logo, Aamir Razzak Orcid Logo, Nicholas Claydon Orcid Logo, Thomas Hallett Orcid Logo, Graca Coutinho Orcid Logo, Anuradha Kulasekaran Orcid Logo, Lydia Powell Orcid Logo, Richard J. Stanton Orcid Logo, Elaine L. Ferguson Orcid Logo, David W. Thomas Orcid Logo, Katja E. Hill Orcid Logo

Journal of Oral Microbiology, Volume: 17, Issue: 1

Swansea University Author: Lydia Powell Orcid Logo

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Abstract

Background : Hexylresorcinol (HR) lozenges provide symptomatic relief for sore throats. Despite its recognised anaesthetic and antiseptic properties, evidence of HR bactericidal activity in these formulations is limited, being only recently described in planktonic bacteria. We defined antimicrobial/...

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Published in: Journal of Oral Microbiology
ISSN: 2000-2297
Published: Informa UK Limited 2025
Online Access: Check full text

URI: https://cronfa.swan.ac.uk/Record/cronfa69957
Abstract: Background : Hexylresorcinol (HR) lozenges provide symptomatic relief for sore throats. Despite its recognised anaesthetic and antiseptic properties, evidence of HR bactericidal activity in these formulations is limited, being only recently described in planktonic bacteria. We defined antimicrobial/antiviral activity in planktonic and biofilm models and characterised the pharmacokinetics of HR release from lozenges. Methods : Antimicrobial activity (purified or released from lozenges) was determined against oropharyngeal pathogens using minimum inhibitory concentration (MIC) and Log10 reduction assays. Antiviral activity was determined by suspension test (EN14476). Antibiofilm effects employed minimum biofilm eradication concentration assays and confocal laser scanning microscopy. HR release from lozenges was studied in vitro and in vivo using HPLC. Results : HR exhibited MICs ≤ 16 µg/mL against 19/25 strains including: Streptococcus, Staphylococcus and Candida spp. Marked bactericidal activity (>3log10; >99.9% reduction) occurred within 10 minutes. Significant anti-biofilm activity was evident in streptococcal and candidal biofilms (p < 0.05). Log10 reduction in virucidal infectivity of HR in lozenges ranged from 1-log10 to 3.5-log10. In vivo, HR exhibited rapid release (within 1 minute) from lozenges into saliva. Conclusion : Rapid release and antimicrobial activity of HR against oropharyngeal pathogens was evident, occurring at concentrations ≥ 2-fold lower than present in saliva, highlighting the potential application of HR in the treatment of oropharyngeal infections.
Keywords: Hexylresorcinol, antimicrobial, oropharyngeal pathogens, antiviral, planktonic, biofilm
College: Faculty of Medicine, Health and Life Sciences
Funders: The work was supported by Reckitt Health Ltd, UK; Reckitt Benckiser Pharmaceuticals.
Issue: 1