Phospholipid-based emulsifiers for sunscreen development: impact of UVA and effect on skin properties in vitro, ex vivo, and in vivo
Mag. Dr. Victoria Klang1) – University of Vienna, Austria
M.Sc. Katja Steiner (PhD fellow sponsored by the PRC) - University of Vienna, Austria
In our project, we hypothesize that due to the known biocompatibility of phospholipid derivatives and their lack of groups with distinct photoactivity, phospholipids could be useful for the stabilization of fluid sunscreen emulsions. Since no literature data on this topic exist, we aim to evaluate the behavior of different lecithin-based emulsifiers in aqueous dispersion and fluid oil-in-water emulsions under photo-stress. We aim to compare their behavior to conventional anionic and nonionic surfactants currently used in marketed products (negative control) and a known photosensitizer (for example, diclofenac sodium as positive control) to exclude any phototoxic or irritation potential.
To this end, we will employ different established methods. In vitro phototoxicity studies will be conducted using human primary cells.1) Ex vivo diffusion cell studies and biophysical analysis of skin parameters, for example by confocal Raman spectroscopy, will serve to evaluate the effect of different test compounds and UV-A on skin barrier function. In vivo studies on human volunteers will be conducted, and corneocyte morphology after treatment and UVA irradiation will be conducted using atomic force microscopy.2) The obtained knowledge will be relevant for the research community focusing on formulation development in the pharmaceutical and cosmetic sector and may contribute to the development of sunscreen formulations based on sustainable raw materials.
Benefit for the community
Dermal preparations based on phospholipids have many applications. To successfully establish their use in sustainable sunscreens, knowledge of their behavior under photo-stress is essential and reference values to other common surfactants are of high interest to enable an informed choice in product development both in academia and industry.
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