A new eco‐friendly and water‐resistant sunscreen agent: Lecithin‐based multilamellar liposomes

Abstract Background UV skin exposure is an important matter of public health, as the worldwide rising prevalence of skin cancers indicates. However, a wide majority of commercially available sunscreens are responsible for ocean ecosystem damages such as coral reef degradation and phytoplankton mortality. Aims To answer the urge for new eco‐friendly UV filters, we studied the use of lecithin‐based multilamellar liposomes (MLLs) of controlled size and elasticity as a bio‐sourced and biodegradable alternative to classic sunscreens. These parameters control allows different skin layers targeting. Methods The performance of two different MLLs compositions and a commercially available SPF50+ water‐resistant liposomal sunscreen was compared on skin explants. SC‐MLLs target the stratum corneum and Epi‐MLLs the whole epidermis. Preparations were applied prior to skin irradiation. Their efficiencies were evaluated histologically (hematoxylin and eosin staining plus cyclobutane pyrimidine dimer [CPD] immunostaining) and by skin barrier quality assessment (trans‐epithelial electrical resistance). Adhesiveness to the skin was also investigated. Results Altogether, ex vivo results indicate MLLs offer a solar protection as effective as a SPF50+ water‐resistant liposomal sunscreen but with a better skin adhesiveness and an improved skin barrier function. Conclusion Lecithin‐based MLLs of controlled physicochemical parameters can be used as a new eco‐friendly and water‐resistant agent for solar protection. The stratum corneum targeted action of SC‐MLLs appears to be more interesting, as SC‐MLLs exhibit an overall better performance than Epi‐MLLs at a lower cost. The skin barrier improvement showcased could be of interest to people suffering from dry skin or skin barrier impairment related disease.