Development of a new SPF50+ photoprotection product to protect against post-inflammatory hyperpigmentation using an ecobiological approach

A photoprotection product is often used after certain aesthetic procedures, particularly to prevent post-inflammatory hyperpigmentation (PIH). The aim of the studies carried out was to develop a new repairing SPF50+ photoprotection product, formulated based on the ecobiological approach, which considers the skin as a living ecosystem interfacing with its internal and external environment and preserves its natural biology. Four experimental studies were carried out targeting the biological mechanisms of the skin, in addition to two clinical studies.

Two experimental studies assessed the protective effect via TEWL in 10 subjects each, before and after the application of a blotter or rubbing. There was a significant improvement in the treated area compared with the area without any product, with a 21.4% reduction in TEWL after application of blotting paper and a 7.8% reduction after rubbing. A 3^rd study demonstrated the breathable effect via maintaining transcutaneous O2 and CO2 partial pressure in 21 subjects, using a radiometer, versus untreated skin. A 4^th metagenomics study targeting the cutaneous microbiome at the interface between the skin and the environment in 18 subjects was carried out in order to measure microbial diversity (Shannon index) after disinfection and after applying or not applying the product. Microbial diversity was restored after 3 hours, unlike in the untreated area. A non-comparative clinical study was carried out with application of the photoprotection product (twice a day, 14 days) in 32 subjects with the assessment of post-laser PIH. An overall scar score composed of three sub-scores (inflammation, scar appearance, functional signs) was determined by a dermatologist and instrumental measurements were taken (TEWL, Visia®). There was a significant reduction in the overall scar score immediately after laser surgery (-13.7%), on D1 (-20.4%), on D3 (-29.9%), on D7 (-47.4%) and on D14 (-57.1%) compared with D0. In particular, the PIH parameter was significantly reduced by 21.8% on D14 vs. D0 and, among the functional signs, burning sensations were reduced by 69.2% as soon as the photoprotection product was applied. In addition, the instrumental analysis showed a significant reduction in measured redness on application of the product (-7.3%) and in pigmentation on the total surface area (-17.9%) compared with the initial condition on D1, with homogeneity improved by 22.4%; these parameters were reduced by 46% and 100% on D14 respectively, compared with D0. A reduction in TEWL was also obtained from D1 (-6.5% vs. after laser therapy) with a return to baseline on D7. The product was well tolerated by all the subjects.

In conclusion, this healing SPF50+ photoprotection product, designed using an ecobiological approach, promotes the natural healing process while protecting against UV rays; it respects the skin’s ecosystem, in particular its microbiome, for optimal healing without hyperpigmentation.