Polymer may strengthen sunscreen SPF and functionality: L’Oréal study

The study, accepted into the International Journal of Cosmetic Science​, details how the polymer called C12-22 alkyl acrylate/hydroxyethylacrylate copolymer (AAHCP), along with different formulations and emulsions were tested. Ultimately the researchers created one sunscreen formulation that was tested with an in vivo study and showed positive results.

“In our constant quest for optimal photoprotection, we keep looking for innovative components to reach the best efficacy and most desirable sensorial properties for our sunscreen products,” the authors wrote. “In this context, we selected an interesting polymer, abbreviated AAHCP, and designed several knowledge and application studies to finally create a brand-new sun care technology.”

AAHCP is a semi-crystalline material that can be used in two different ways — as an emulsifying system or as an oily phase structuring ingredient within a surfactant-based emulsion, said the researchers. The researchers created several different formulations to better understand how it would perform best. They found when they added 1% AAHCP to a conventional sunscreen emulsion, there was a significant increase in SPF.

Following the development and testing of those formulas and emulsions, one sunscreen formulation was prepared for further study that included 2.5% of AAHCP and had SPF50+. In addition to its SPF factors, AAHCP also helped create a more desirable feel for the sunscreen.

“The innovation lies in the development of a new generation of surfactant-free emulsions based on AAHCP that give a perfectly uniform film while boosting filters efficiency, without compromising on sensorial features and globally designed as NetlockTM technology,” the authors wrote.

The tested sunscreen with AAHCP was deemed water resistant, sweat resistant and did not migrate after a sauna test.

Another study, which included participant use of the sunscreen for 21 days, revealed positive feedback including that “the skin seemed smoother, softer, suppler, velvetier, felt more hydrated, seemed nourished, felt soothed, and the product left the skin comfortable,” in addition to reported non-oily feeling. The study included 44 adults.

“Thanks to AAHCP, it has been possible to design sunscreen products that were evaluated through in vitro and in vivo tests,” the authors wrote. “The first results show that such sunscreen product deposits a very light, almost invisible, pleasant film that does not stick, does not shine, nor leave white marks, remaining uniform to ensure a high level of protection.”

Source: International Journal of Cosmetic Science​
September 17, 2023 https://doi.org/10.1111/ics.12889​​
“New Formulation Technology to Boost Sun Protection”​
Authors: H. Meaudre, et al.