Based on the ionic character of the surfactant, 3 and 4 are cationic surfactants and 5 and 6 are amphoteric surfactants. Therefore, the mechanisms of antiviral activity and effects on skin barrier function may be fundamentally different between them. Interestingly, the strength of the effect of surfactants on skin barrier function does not depend on the ionic properties of the surfactant. On the other hand, the influence of ionic properties on the antiviral activity is unknown. However, it is important information that some of these are effective in enhancing skin permeation of substances. Since 3 and 6 have a relatively small effect on the skin barrier function, they may be safely applied for sterilization.
The use of surfactants, which strongly influence the skin barrier function, may allow the transdermal entry of an object that is below the cellular level, i.e. viruses. This effect on skin barrier function may be mitigated by mixing with a surfactant having different ionicity, and we are currently studying it. Properly formulated quaternary ammonium type surfactants product may be able to prevent transdermal entry while maintaining anti- SARS-CoV-2 activity.
Because the experiments were performed on mice-extracts skin, please pay attention that these results may differ from human skin.