Materials
The ethanol concentration (% w/w) and the antimicrobial activity of seven different ABHRs was evaluated. The composition (according to label claims) and regulatory classification of the analysed alcohol gels are reported in Table I. All products were purchased from a local pharmacy, except for Gel 4, which was purchased in a local supermarket.
Table I The composition and regulatory classification of the analysed alcohol gels
Entry Composition Ethanol* Regulation
Gel 1 Ethanol** 66 g; excipients and water up to 100 g. 66% Cosmetic
Gel 2 Ethanol (96%) 74 g; excipients and water up to 100 g. 74% Biocide
Gel 3 Alcohol; water; isopropyl alcohol; glycerin; Hydroxypropyl Methyl Cellulose; Aloe barbadensis leaf juice; parfum. N/R*** Cosmetic
Gel 4 Water; Denatured alcohol; glycerin; parfum; carbomer; limonene; linalool; aminomethyl propanol. N/R Cosmetic
Gel 5 Ethanol 70 g; excipients and water up to 100 g. 70% Biocide
Gel 6 Denatured alcohol; water; propylene glycol; carbomer, glycerin; sodium hydroxide; citral; citronellol; geraniol; hydroxycitronellal; linalool, limonene; CI42090. N/R Cosmetic
Gel 7 Denatured alcohol; water; aloe barbadensis leaf juice; citrus lemon peel oil; carbomer; propylene glycol; triethanolamine; PEG-40 hydrogenated castor oil, limonene; sodium benzoate; potassium sorbate; citric acid. 60% Cosmetic
*The percentage of ethanol is w/w for the products authorised as biocide, while the unit is unknown, since not reported, for the cosmetic ones
**Alcohols, as well as other ingredients with potential antimicrobial activity, are highlighted in bold
***N/R not reported