Writing in the international patent, Unilever said that out of the three main types of film formers – polysaccharide-based, acrylate-based and resin-based – it found the latter could be used to prevent pollution damage to the skin, specifically lipoperoxidation-based damage. Whilst the company didn’t outline specific applications, findings in the patent relate to on-skin protection.
“The present invention has surprisingly found that resin-based film formers have enhanced efficacy in preventing lipoperoxidation-based damage to the skin, especially lipoperoxidation-based damage caused by pollution,” Unilever wrote in its patent filing.
These resin-based film formers, it said, performed “better than other categories of film formers” in preventing pollution-driven oxidative damage to the skin and specifically protected against damage caused by airborne “particulate matter”.
Resin-based film formers that had proven “particularly effective” were trimethylsiloxysilicate and polypropylsilsesquioxane, it said.
Air pollution a ‘major’ health concern
Unilever said air pollution, a heterogeneous mixture of chemicals and solid particles emitted from natural and anthropogenic sources, was a “major concern from a health perspective to both susceptible and healthy members of the population”. And whilst skin provided an important barrier function, the company said the skin’s defensive capacity was limited, particularly if environmental stressors were high, disturbing skin structure and leading to skin diseases like contact dermatitis, psoriasis or erythema.
Unilever said the skin was “one of the most common routes” of exposure to air pollution, and in vitro and in vivo studies had shown a variety of biological effects after chronic and acute exposure, including oxidative stress and inflammation – both important contributors to extrinsic skin ageing.
Lipid peroxidation – the oxidative degradation of lipids – was one “critical mechanism” driving pollution damage in the skin, it said, and “a crucial step in the pathogenesis of several disease states in adult and infants” that could cause “significant tissue damage”.
“There is therefore clearly a need to address the lipoperoxidation damage to skin caused by the aforementioned pollutants and biological mechanisms,” Unilever said.
Whilst film formers were already used extensively in beauty and personal care applications, it said they were predominantly used in hair care formulations for styling and shine; SPF skin care formulas for water-resistance, and colour cosmetics for increased wear. There had only been limited research conducted on use of film formers to address pollution damage to skin, it said.
Unilever said that it was appreciated film formers could be capable of protecting the skin against pollution, but so far mention had not been made of an application to prevent lipoperoxidation-based damage.
Wider interest in measuring pollution protection
In an earlier and separate international patent*, Unilever outlined a method involving fluorescence-based assays for evaluating the efficacy of leave-on cosmetic compositions in preventing or inhibiting particulate pollutants from contacting skin.
It said that whilst a range of testing methods already existed, including colour-changing indicators, there remained a need for “a robust method” to determine the dynamics of pollutant penetration over a period of time to determine efficacy of cosmetics that claim to prevent or delay contact.
WIPO International Patent No. WO/2020/058155
Published on: March 26, 2020. Filed on: September 16, 2019.
Title: “Prevention of pollution damage to the skin of an individual”
Inventor: Unilever PLC – RK. Bhogal, S. Ghosh Dastidar, DJ. Messenger, J. Muscat and C. Yuan
WIPO International Patent No. WO/2020/053019
Published on: March 19, 2020. Filed on: September 2, 2019.
Title: “Evaluating the efficacy of leave-on cosmetic compositions to protect skin from pollutants”
Inventor: Unilever PLC – Y. Fang, S. Meng and S. Yi