Antimicrobial hand rub : an investigation of the various chemicals used in the concentrate skin formula to enhance the product performance

Ibbotson, J

Abstract

The following research project was conducted in order to evaluate the antimicrobial efficacy of an alcohol-free skin concentrate formula intended for use on hands. Substitute compounds for alcohol in antimicrobial formulae is receiving much interest due to the tendency of alcohol to dry and irritate the skin after repeated use. As well as assessing the formula’s efficacy, the individual components were assessed using a series of certified antimicrobial assays. Chief among the components of the skin concentrate formula was chlorhexidine digluconate, a prominent potent antimicrobial compound. The bacterial strains selected for exposure to antimicrobial susceptibility assays were Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. Furthermore, in addition to assessing antimicrobial potency, parallel cytotoxicity studies were performed on a mammalian cell line, to determine the extent of potential toxic behaviour demonstrated by the skin concentrate and its constituents. The chosen mammalian cell viability assay was the MTT (3-4(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide tetrazolium) reduction assay. The selected mammalian cell line for cytotoxicity studies was A549, which is a lung-derived carcinoma cell line. Topical antibacterial compounds are commonplace in the healthcare, domestic and industrial environments; hence the importance of assessing their cytotoxicity cannot be undervalued.


Silver is recognised as an effective antimicrobial, especially in the healthcare setting where it is incorporated into wound dressings to combat external infections. Silver sulfadiazine and silver nitrate represent two of the most common silver-containing antimicrobial compounds. For comparison against silver containing compounds, silver ions were generated in solution using a Dowex® cation exchange resin for subsequent antimicrobial susceptibility and cytotoxicity testing.


The potent antimicrobial efficacy of chlorhexidine digluconate, alone and in combination with other excipients, was observed. All three strains proved to be susceptible. Furthermore, silver displayed similar potent antimicrobial activity against all three strains. However, cytotoxic properties were observed for chlorhexidine digluconate and silver. Therefore, while chlorhexidine diguconate is a distinguished antimicrobial compound, the cytotoxic properties associated with it suggest a replacement compound with reduced cytotoxic properties may be required for incorporation into the formula.

Citation

Ibbotson, J. (in press). Antimicrobial hand rub : an investigation of the various chemicals used in the concentrate skin formula to enhance the product performance. (Dissertation). University of Salford

• Thesis Type: Dissertation
• Acceptance Date: Dec 18, 2018
• Deposit Date: Dec 18, 2018
• Publicly Available Date: Dec 18, 2018