Formulation of Pickering Emulsions for topical applications: The feasibility of cosmetic formulations and the forecasting of environmental impacts
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Presented by: Aurélie ASDRUBAL
Some usual surfactants have a measurable activity on the skin's barrier function and microbiota1 and are responsible for environmental contamination due to its non-degradability 2,3. Those facts explain the increasing interest for the Pickering Emulsions based on the possibility to replace these surfactants with solid particles. This new approach not only is it attractive for the cosmetic field because of the greater resistance to coalescence4 but also with a rational choice of particles it can be less toxic for the environment and the skin. Most of the research in this field is focused on the theoretical aspect of Pickering, with emulsions composed of water, oil, and particles only. There is no information about complex, totally emulsified, and stable cosmetic emulsions. Furthermore, the environmental and toxicological impacts of these Pickering emulsions are not yet investigated. However, it is likely that contact with the other ingredients will change the properties of the introduced particles. This study aims to formulate stable, complex, and homogenous Pickering Emulsion suitable for the cosmetic field and topic application. Once this formulation is stable its environmental and toxicological impacts would be studied for both emulsion and particles. That’s why non-destructive particles extraction processes are developed.
Models particles5 (modified titanium dioxide and modified silica) studied by the URCOM laboratory can form simple, stable, and totally emulsified systems. These models were used for complexifying to obtain a formula close in composition to a real commercial product. Then the complexified formula will be tested with inorganics (Smectite clays) or organics (Chitosan, Native starch, and modified starch) particles highlighted by bibliographic and experimental research. Interactions between ingredients in the different formulas (oil phase, texturing agents…) will be studied from microstructure to macroscopic characterization to highlight key parameters for totally emulsified complex topical emulsions.
For the environmental impacts, the particles have to be extracted from the media, which will allow characterizing its surface. A modification of the surface structure or physicochemical properties should be an indicator of the non-stability of the particles in the formulation and will be an indicator of potential ecological or skin toxicity. That’s why extraction methods must be non-destructive and the particles must remain unchanged by the extraction process. The aim of our study is also to develop such extraction processes.
Particles are an alternative to usual problematic surfactants. This study shows the stability of complex Pickering emulsion composed of cosmetic ingredients and will give some tools to control such formulation. Non-destructive extraction methods are used to control the size and the surface proprieties of the particles before and after introduction in the formulation.
1 Lémery, E.; Briançon, S.; Chevalier, Y.; Bordes, C.; Oddos, T.; Gohier, A.; Bolzinger, M.-A. Skin Toxicity of Surfactants: Structure/Toxicity Relationships. Colloids and Surfaces A: Physicochemical and Engineering Aspects 2015, 469, 166–179. https://doi.org/10.1016/j.colsurfa.2015.01.019.
2 Jackson, M.; Budgen, N. Comprehensive Review of Several Surfactants in Marine Environments: Fate and Ecotoxicity. 2016, Vol. 35, 10. http://dx.doi.org/10.1002/etc.3297.
3 Garcia, M. T.; Campos, E.; Marsal, A.; Ribosa, I. Fate and Effects of Amphoteric Surfactants in the Aquatic Environment. Environment International 2008, Iss 7, Pp 1001-1005, 5. http://dx.doi.org/10.1016/j.envint.2008.03.010.
4 Colloidal Particles at Liquid Interfaces; Binks, B. P., Horozov, T. S., Eds.; Cambridge University Press: Cambridge, 2006. https://doi.org/10.1017/CBO9780511536670.
5 Terescenco, D.; Hucher, N.; Picard, C.; Savary, G. Sensory Perception of Textural Properties of Cosmetic Pickering Emulsions. International Journal of cosmetic science 2020, 42 (2), 198–207. https://doi.org/10.1111/ics.12604.
Models particles5 (modified titanium dioxide and modified silica) studied by the URCOM laboratory can form simple, stable, and totally emulsified systems. These models were used for complexifying to obtain a formula close in composition to a real commercial product. Then the complexified formula will be tested with inorganics (Smectite clays) or organics (Chitosan, Native starch, and modified starch) particles highlighted by bibliographic and experimental research. Interactions between ingredients in the different formulas (oil phase, texturing agents…) will be studied from microstructure to macroscopic characterization to highlight key parameters for totally emulsified complex topical emulsions.
For the environmental impacts, the particles have to be extracted from the media, which will allow characterizing its surface. A modification of the surface structure or physicochemical properties should be an indicator of the non-stability of the particles in the formulation and will be an indicator of potential ecological or skin toxicity. That’s why extraction methods must be non-destructive and the particles must remain unchanged by the extraction process. The aim of our study is also to develop such extraction processes.
A complex formula has been developed and is stable and totally emulsified with the model particles. Some particles showed promising stability and uniformity in simple and complex formulas. Extraction methods have been developed and will be presented. The size and the surface properties of the particles are studied before and after introduction in both simple and complex formulas.
Particles are an alternative to usual problematic surfactants. This study shows the stability of complex Pickering emulsion composed of cosmetic ingredients and will give some tools to control such formulation. Non-destructive extraction methods are used to control the size and the surface proprieties of the particles before and after introduction in the formulation.
1 Lémery, E.; Briançon, S.; Chevalier, Y.; Bordes, C.; Oddos, T.; Gohier, A.; Bolzinger, M.-A. Skin Toxicity of Surfactants: Structure/Toxicity Relationships. Colloids and Surfaces A: Physicochemical and Engineering Aspects 2015, 469, 166–179. https://doi.org/10.1016/j.colsurfa.2015.01.019.
2 Jackson, M.; Budgen, N. Comprehensive Review of Several Surfactants in Marine Environments: Fate and Ecotoxicity. 2016, Vol. 35, 10. http://dx.doi.org/10.1002/etc.3297.
3 Garcia, M. T.; Campos, E.; Marsal, A.; Ribosa, I. Fate and Effects of Amphoteric Surfactants in the Aquatic Environment. Environment International 2008, Iss 7, Pp 1001-1005, 5. http://dx.doi.org/10.1016/j.envint.2008.03.010.
4 Colloidal Particles at Liquid Interfaces; Binks, B. P., Horozov, T. S., Eds.; Cambridge University Press: Cambridge, 2006. https://doi.org/10.1017/CBO9780511536670.
5 Terescenco, D.; Hucher, N.; Picard, C.; Savary, G. Sensory Perception of Textural Properties of Cosmetic Pickering Emulsions. International Journal of cosmetic science 2020, 42 (2), 198–207. https://doi.org/10.1111/ics.12604.