In order to keep TRI open through the COVID pandemic, and to avoid shortages of cleaning products, Alison Robinson took the initiative to make batches of our own hand sanitizer for the staff to use. Many thanks to Alison for going the extra mile and helping to keep TRI running!
Alison had to do some research first before making her own alcohol-based sanitizer, since the rules for making these products were not yet clear. Here are some of her very interesting learnings.
Firstly, hand washing is vital. Since the emergency of Coronavirus (SARS-CoV-2) in the end of 2019, which lead to a word pandemic, one of the most effective ways of avoiding the contamination, recommended by World Health Organization (WHO), was keeping your hands clean. This can be done by washing your hands with soap and water or using alcohol-based sanitizers, which must be between 60% and 90% concentration.
The mechanism of action of hand sanitizers and detergents is the disruption of the virus lipid envelope (Golin et al., 2020). It was also suggested the entrapment of virus in surfactants micelles, which are formed when using surfactants in a concentration higher than CMC (Critical Micellar Concentration) values (Promad et al.,2020).
Non-alcohol-based hand sanitizers are also described to be effective against SARS-CoV-2 contamination. These products are mostly based on benzalkonium chloride - BC, a quaternary ammonium, which can be considered less irritant than alcohol products and the mechanism of action consists in the disruption of the lipophilic membrane by the cationic headgroup in BC molecule (Golin et al., 2020).
According to WHO, cleaning your hands with water and soap is preferable than using hand sanitizers. Hand sanitizers, both alcohol and non-alcohol based are always effective against enveloped virus, such as SARS-CoV-2, Zika, H1N1, but studies have shown that they are not effective against non-enveloped virus such as Hepatitis A (Golin et al., 2020).
The most common surfactants used in hand soaps are Sodium Laureth Sulphate, sodium lauroyl sarcosinate, cocamide diethanolamine, sodium lauroyl oat amino acids, disodium cocoamphodiacetate, decyl glucoside, sodium cocoyl glutamate, lauryl glucoside, and cetrimonium chloride. These are also associated with irritant contact dermatitis due to the alteration of skin barrier integrity that can lead to increase in TEWL (Transepidermal Water Loss) and increase skin sensitivity (Rundle et al., 2020). In this context, the association with moisturizing ingredients in the formulation is always important to avoid skin irritation. Alcohol based sanitizers are often associated with emollients which can decrease the risk of irritant contact dermatitis and are less associated with skin irritation than detergents.
The use of biosurfactants have also been studied to reduce the impact of chemical detergents in the environment. Biosurfactants, such as glycolipids, lipopeptides, phospholipids, polymeric surfactants, and particulate surfactants can be an alternative to synthetic surfactants, presenting the advantage of being biodegradable products. Plant based surfactants, as saponins are also interesting molecules that present detergent activity and can be used in formulations for hand sanitizing. The main disadvantage of this products is the increased price. Although more studies are needed, it is an interesting choice for conventional hand sanitizers (Davery and Dutta, 2021).
Hand hygiene is very important to avoid the contamination not only by COVID-19, but also against other infectious diseases. The use of both soap and water or hand sanitizers alcohol or non-alcohol based are indicated, being important to choose formulations with emollients (moisturizing ingredients) to avoid irritation. Another important tip is to use skin moisturizer after cleaning your hands, this way you can reduce both the risk of contamination and skin irritation.
KEEP YOUR HANDS CLEAN, KEEP SAFE!
Daverey A, Dutta K. COVID-19: Eco-friendly hand hygiene for human and environmental safety. Journal of Environmental Chemical Engineering 9, 104754, 2021.
Golin AP, Choi D, Ghahary A. Hand sanitizers: A review of ingredients, mechanisms of action, modes of delivery, and efficacy against coronaviruses. American Journal of Infection Control 48, 1062−1067, 2020.
Pramod K, Kottab S, Jijitha US, Aravindc A, Abu Tahird M, Manjua CS, Gangadharappae HV. Surfactant-based prophylaxis and therapy against COVID-19: A possibility. Medical Hypotheses 143, 110081, 2020.
Rundle, CW, Presley CL, BA, Militello M, Barber C, Powell DL, Jacob SE, Atwater AR, Watsky KL, Yu J, Dunnick CA. Hand hygiene during COVID-19: Recommendations from the American Contact Dermatitis Society. J AM ACAD DERMATOL, 83, 6, 1730 – 1737, 2020.