How to protect against covid-19 while protecting our skin hands?

Frequent use of hand sanitizer can cause skin barrier alterations (hydrolipidic film and intercellular lipidic cement disruption) leading to dryness, scaling, itching, burning and even erosions and cracks. Therefore, we developed a safe and efficient alcohol-based formula for hand disinfection according to US FDA and WHO recommendations, that we enriched with lipids. This patented Lipo alcoholic Biphase (LB) is composed of 10% biomimetic oily phase (shea oil, squalane), 74.5% (m/m) ethanol, water, and a blue dye to confirm the good homogeneity after shaking. The aim of this work is to assess the immediate and long-lasting protection effect of the Lipo alcoholic Biphase on skin barrier, versus a standard hydroalcoholic solution (HS) with glycerin.

The virucidal activity against enveloped virus (including SARS-CoV-2) was evaluated in clean conditions by the standard test NF EN 14476+A2, the bacterial activity by NF EN 13727+A2 test and the yeasticidal activity by NF EN 13624 test. To evaluate the immediate protecting effect, the residual oily film was measured using a sebumeter on the forearms of 10 females (aged 22 to 43) before, immediately and 15 minutes after a single application of the LB or of the HS (2.4 μl/cm²). In a single-blind study, we evaluated the long-lasting protection effect by measuring the transepidermal water loss (TEWL) at day 0 (D0), D7 and D14. Nineteen females (aged 25 to 69) with dry to very dry skin on the hands, and/or with an atopic tendency, used the 2 products on hands for 14 days (5 sprays on each hand 10 times a day). To avoid mixing from hand to hand, the products were spread with the opposite forearm. The right biceps corresponded to the untreated area. To assess the safety and the subjective efficacy of the LB after 21 days of use (as described for the TEWL), 20 subjects (95% female, aged 23 to 54) were included in an open intra-individual study under medical supervision, using a self-assessment questionnaire. All statistical analysis was performed with the Student t-test.

The LB was virucidal, bactericidal and yeasticidal by eliminating in 30 seconds more than 99.9% of enveloped viruses, bacteria, and yeast. In addition, skin barrier studies showed that the LB:

• left a nourishing oily film immediately after application contrary to the HS, and lasted after 15 minutes (96 and 1 μg/cm², respectively).
• improved the TEWL at D7 on the hands vs the untreated area and vs the HS (-19.7% vs -3.3% and -6.8%, respectively; p<0.001) and at D14 (-24.2% vs -2.1% and -3.6%, respectively; p<0.001).
• improved the TEWL even from D7 to D14 vs D0 (-19.7% and -24.2% respectively, p<0.001), contrary to the untreated area and the HS.
• was very well tolerated on the hands for 95% of the subjects at D21.
• ensured for 85% to 100% of the subjects (somewhat to strongly agreed) at D21: disinfection and nutrition (immediately and long-lastingly), protected the skin from drying, limited cutaneous alterations, moisturized and protected the skin, leading to a smoother and softer skin.