Effect of New Surfactants on Biological Properties of Liquid Soaps.

Liquid soaps are the basic cosmetics used to clean the skin of the hands. Frequent hand washing prevents viral contamination but may damage the skin's hydro-lipid layer, leading to various types of irritation. Therefore, four liquid soap formulas were developed with three amphoteric surfactants: Cocamidopropyl Betaine (LS II), CocamidopropylHydroxysultaine (LS III), and newly synthesized Evening PrimroseaamidopropylSulfobetaine (LS IV). We evaluated the skin irritating potential (zein number, bovine albumin test) and cytotoxicity (AlamarBlue™, Cell viability, and Cell cycle assays) on HaCaT cell line. We observed lower values of the zein number and bovine albumin tests after adding soaps with surfactants (the highest differences in LS IV) compared to the base soap (LS I). However, LS I and LS II did not differ in cytotoxic assays. Therefore, adding LS III and LS IV seems potentially more dangerous to the cells. However, it should be noted that cells were continuously exposed to liquid soaps for more than 24 h, so its cytotoxic effects after dermal use in humans may be unnoticeable. Concluding, results suggest that the newly synthesized LS IV should improve the safety of liquid hand washing soaps.

Rosin Soap Exhibits Virucidal Activity.

Chemical methods of virus inactivation are used routinely to prevent viral transmission in both a personal hygiene capacity but also in at-risk environments like hospitals. Several virucidal products exist, including hand soaps, gels, and surface disinfectants. Resin acids, which can be derived from tall oil, produced from trees, have been shown to exhibit antibacterial activity. However, whether these products or their derivatives have virucidal activity is unknown. Here, we assessed the capacity of rosin soap to inactivate a panel of pathogenic mammalian viruses in vitro. We show that rosin soap can inactivate human enveloped viruses: influenza A virus (IAV), respiratory syncytial virus, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). For IAV, rosin soap could provide a 100,000-fold reduction in infectivity. However, rosin soap failed to affect the nonenveloped encephalomyocarditis virus (EMCV). The inhibitory effect of rosin soap against IAV infectivity was dependent on its concentration but not on the incubation time or temperature. In all, we demonstrate a novel chemical inactivation method against enveloped viruses, which could be of use for preventing virus infections in certain settings. IMPORTANCE Viruses remain a significant cause of human disease and death, most notably illustrated through the current coronavirus disease 2019 (COVID-19) pandemic. Control of virus infection continues to pose a significant global health challenge to the human population. Viruses can spread through multiple routes, including via environmental and surface contamination, where viruses can remain infectious for days. Methods for inactivating viruses on such surfaces may help mitigate infection. Here, we present evidence identifying a novel virucidal product, rosin soap, which is produced from tall oil from coniferous trees. Rosin soap was able to rapidly and potently inactivate influenza virus and other enveloped viruses.

Comparable Environmental Stability and Disinfection Profiles of the Currently Circulating SARS-CoV-2 Variants of Concern B.1.1.7 and B.1.351.

The emergence of novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern with increased transmission dynamics has raised questions regarding stability and disinfection of these viruses. We analyzed surface stability and disinfection of the currently circulating SARS-CoV-2 variants B.1.1.7 and B.1.351 compared to wild type. Treatment with heat, soap, and ethanol revealed similar inactivation profiles indicative of a comparable susceptibility towards disinfection. Furthermore, we observed comparable surface stability on steel, silver, copper, and face masks. Overall, our data support the application of currently recommended hygiene measures to minimize the risk of B.1.1.7 and B.1.351 transmission.

Antiviral efficacy of personal care formulations against Severe Acute Respiratory Syndrome Coronavirus 2.

BACKGROUND: Non-therapeutic interventions such as practicing good hand hygiene continue to be the mainstay of protection from SARS-CoV-2 and other emerging respiratory viruses. METHODS: We have evaluated a range of commercially available personal care products including soaps, handwash liquids and alcohol-based hand sanitizers for antiviral efficacy against a clinical isolate of SARS-CoV-2 using internationally accepted standardized protocols at user-relevant contact time-points and product dilutions. RESULTS: All the tested products resulted in 3 to 4 log reduction of SARS-CoV-2 titer. CONCLUSION: Our data re-affirms recommendations by global public health authorities that proper hand hygiene can reduce SARS-CoV-2 viral load significantly which should likely limit spread of the contagion.

Soap and syndets: differences and analogies, sources of great confusion.

OBJECTIVE: Soap has been used by humankind since ancient times and was probably already known to the Sumerians. It is a fatty acid salt obtained from the reaction of a strong base with a fatty substance of animal (tallow) or plant origin (oil). This reaction is called saponification. Syndets, on the other hand, are much more recent and have been in use for about a century. In the case of liquid syndets, they are mainly alkyl sulphates and their derivatives alkyl ether sulphates while isethionates and sarcosinates are more commonly found in solid syndets. Synthetic soaps and detergents are surfactants and, as such, they have detergent properties. The way soap works accounts for its antimicrobial properties. Thanks to its amphiphilic structure, it is able to interact with the lipid membranes of microorganisms (viruses, bacteria, etc.) and inactivate them. In this coronavirus pandemic period, health authorities worldwide recommend hand washing with soap and water. We therefore wanted to provide a summary of the chemical characteristics and applications of soaps, on the one hand, and synthetic detergents, on the other. Soap is not the only product used for hand hygiene and, given the current situation, alternatives are complex and varied.

Synergistic effects of anionic surfactants on coronavirus (SARS-CoV-2) virucidal efficiency of sanitizing fluids to fight COVID-19.

Our surrounding environment, especially often-touched contaminated surfaces, plays an important role in the transmission of pathogens in society. The shortage of effective sanitizing fluids, however, became a global challenge quickly after the coronavirus disease-19 (COVID-19) outbreak in December 2019. In this study, we present the effect of surfactants on coronavirus (SARS-CoV-2) virucidal efficiency in sanitizing fluids. Sodium dodecylbenzenesulfonate (SDBS), sodium laureth sulfate (SLS), and two commercial dish soap and liquid hand soap were studied with the goal of evaporation rate reduction in sanitizing liquids to maximize surface contact time. Twelve fluids with different recipes composed of ethanol, isopropanol, SDBS, SLS, glycerin, and water of standardized hardness (WSH) were tested for their evaporation time and virucidal efficiency. Evaporation time increased by 17-63% when surfactant agents were added to the liquid. In addition, surfactant incorporation enhanced the virucidal efficiency between 15 and 27% according to the 4-field test in the EN 16615:2015 European Standard method. Most importantly, however, we found that surfactant addition provides a synergistic effect with alcohols to inactivate the SARS-CoV-2 virus. This study provides a simple, yet effective solution to improve the virucidal efficiency of commonly used sanitizers.

Effects of hand disinfection with alcohol hand rub, ozonized water, or soap and water: time for reconsideration?

The effect of alcohol hand rub was tested in eradicating Escherichia coli, and compared with hand wash using ozonized tap water or soap and water. Alcohol eradicated all bacteria in 10 out of 35 participants, but with an average (SD) of 2330 (4227) cfu/mL left after disinfection, whereas ozonized water removed all bacteria in 10 out of 55 participants, with an average of only 538 (801) cfu/mL left (P = 0.045). Soap washing was the most effective with total removal of bacteria in six out of 20 participants, with an average of 98 (139) cfu/mL (P = 0.048 and 0.018 versus ozonized water and alcohol, respectively).