BASF has developed a systematic approach to test standard cosmetic formulations for their anti-pollution efficacy.

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These analyses target four core mechanisms of action: anti-adhesion, removability, anti-penetration and cleansing. The results are used to craft skin care formulations that effectively protect against the adverse impact of particulate pollutants on skin health.

“We want to assist manufacturers in developing skin care products that demonstrably help shield the skin against particulate pollutants,” said Annette Mehling, Ph.D., senior manager skin sciences of BASF. “However, there is no ‘one-size-fits-all’ test for anti-pollution claims, as there are different types of pollutants and consequently, several defense methods that may be needed to protect the skin effectively. This is why we have developed a series of new testing methods that allow for the scientifically sound evaluation of the performance of different cosmetic ingredients and formulations.”

Anti-adhesion and Removability

According to the company, keeping particulate matter (PM) off the skin is a primary line of defense against pollution-induced damage. To translate this starting point into effective skin care products, BASF designed a standardized in vivo test to evaluate the ability of typical ingredients or formulations to decrease particle adhesion and possibly improve removability from pre-treated skin.

The choice of polymers, emollients and emulsifiers in the formulation significantly influences these two parameters. For instance, eleven of the fifteen polymers tested were shown to reduce the adhesion of PM, compared with untreated polluted skin. Numerous emollients and emulsifiers, by contrast, reportedly increased adhesion.

According to BASF, the best results were obtained using a volatile hydrocarbon-based emollient at low concentrations. For emulsifiers, the sugar-based variants performed best.

Anti-penetration

Although PM itself is not absorbed through the skin, BASF reports the particles can be coated with harmful substances that leach into it. To keep skin healthy, reducing the penetration of harmful substances into deeper layers of the skin can therefore be helpful.

In response, an in vitro permeability model simulating the penetration of pollutants through the skin was developed to identify ingredients that help to form a protective layer. According to the company, the right polymer is important in terms of anti-penetration effects.

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Cleansing

The skin is exposed to a wide variety of environmental pollutants throughout the day. It is therefore imperative to remove remaining particles from it.

To test cleansing oils for their properties, BASF used a collagen matrix skin model. And through the analysis of 11 emollients, the company revealed that cleansing performance correlates directly with physicochemical parameters. According to BASF, the best results were achieved with emollients possessing a high spreading value and low viscosity.

Proven Anti-pollution Effects

Finally, BASF researchers incorporated high-performing ingredients for each anti-pollution mechanism described into skin care formulations. While developing the formulations, the team also optimized attributes such as sensory properties and consumer-perceivable benefits such as moisturization or skin mildness. Overall, it was reported that these formulations outperformed products marketed with anti-pollution claims.

For more information, contact BASF.