Skin Barrier Enhancing Alternative Preservation Strategy of O/W Emulsions by Water Activity Reduction with Natural Multifunctional Ingredients

Water activity (a_w) as an important parameter for self-preservation can help to control microbial growth in cosmetic formulations. However, high amounts of water-binding substances are required to lower the a_w enough to affect microbial growth. Since consequences for the skin barrier have been poorly studied so far, we investigated the effect of a_w-lowering agents on both the antimicrobial properties of o/w emulsions and skin physiological parameters. A combination of selected natural humectants (Sodium lactate, Propanediol, Erythritol, Betaine and Sodium PCA) with a total concentration of 28 wt% in an o/w emulsion was able to reduce its a_w from 0.980 ± 0.003 to 0.865 ± 0.005. The challenge test results of the a_w-lowered emulsion showed a convincing microbial count reduction in potentially pathogenic microorganisms. The addition of as little as 0.5% of the antimicrobial multifunctionals Glyceryl Caprylate and Magnolia Officinalis Bark Extract further enhanced the antimicrobial effect, resulting in adequate antimicrobial protection. Moreover, twice-daily application of the a_w-lowered emulsion for a period of four weeks led to a skin barrier-enhancing effect: TEWL significantly decreased, and SC hydration significantly increased. Thus, we present an opportunity to replace conventional preservatives with a natural alternative preservation strategy that has been shown to offer benefits for the skin. View Full-Text

Keywords: water activity; self-preservation; hurdle technology; formulation; skin barrier; humectants; multifunctional ingredients; antimicrobial

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MDPI and ACS Style

Nadarzynski, A.; Scholz, J.; Schröder, M.S. Skin Barrier Enhancing Alternative Preservation Strategy of O/W Emulsions by Water Activity Reduction with Natural Multifunctional Ingredients. Cosmetics 2022, 9, 53. https://doi.org/10.3390/cosmetics9030053

AMA Style

Nadarzynski A, Scholz J, Schröder MS. Skin Barrier Enhancing Alternative Preservation Strategy of O/W Emulsions by Water Activity Reduction with Natural Multifunctional Ingredients. Cosmetics. 2022; 9(3):53. https://doi.org/10.3390/cosmetics9030053

Chicago/Turabian Style

Nadarzynski, Alexandra, Jonas Scholz, and Markus S. Schröder. 2022. "Skin Barrier Enhancing Alternative Preservation Strategy of O/W Emulsions by Water Activity Reduction with Natural Multifunctional Ingredients" Cosmetics 9, no. 3: 53. https://doi.org/10.3390/cosmetics9030053

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Skin Barrier Enhancing Alternative Preservation Strategy of O/W Emulsions by Water Activity Reduction with Natural Multifunctional Ingredients

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