The Influence of Viscosity on the Antimicrobial Activity of Simple Alcoholic-Based Hand Sanitizer for Infection of Covid-19 in Nigeria

Aim: This study was carried out to analyze and evaluate the influence of viscosity on the antimicrobial activity of simple alcoholic-based hand sanitizer preparations. 
Methods: The preparation of different viscosities of hand sanitizer was done by the introduction of carbomer to define its physicochemical stability. Two folds serial dilution of the test product using isopropyl alcohol and ethanol as alcohols and biocide efficiency to determine the antimicrobial activity using killing time assay were carried out. 
Results: The pH was adjusted to 7.29 and 7.11 respectively, which shows the neutrality of the products.   More so, the pH of the two test products proved to be good and hence, stable. In terms of viscosity, it decreased as the concentration decreased at 0.07% for most of the organisms which indicated good antimicrobial activity on the bacterial and fungi strain used. However, concentrations of isopropyl-formulated test product were more effective than the ethanol-based product on the bacterial strains, with Pseudomonas aeruginosa having the highest percentage of microbial death at 92.5%.  Although, the ethanol-based products showed higher antimicrobial activity against fungi strains than the isopropyl test product. 
Conclusion: Viscosity influences the activities of alcohol-based hand sanitizers since less viscous test product has a less concentration. Thus, more water denatures the proteins of the microorganism and limits the release of the active ingredient from the formulation. Sequel to this, viscosity enhancers like thickeners and gelling agents like carbomer should be used minimally in the formulation of these products.