Pickering Emulsion with Functionalized Particles: Formulation and Application to Sunscreens.
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Presented by: Heleen Kibbelaar
Introduction:
Pickering emulsions have recently gained much attention in the cosmetic formulation community because of their ability to stabilize emulsions such as sunscreens and they offer a promising alternative to classical surfactants, which are known to cause skin irritation. Pickering emulsions use solid (nano)particles with the key advantage to be functionalized. For instance, very recent advances in sunscreen formulation suggest using nanoparticles with encapsulated (organic) UV filters to optimize solar protection. In this work, we formulate and study surfactant-free sunscreen emulsions over a broad range of silicon oil concentrations, solely stabilized by silica nanoparticles (NPs). Our formulation provides good stability of the emulsion in time with good UV absorbance performance.
Methods used:
Silica particles containing the organic UV filters avobenzone and octocrylene were mixed with a model silicone oil phase to obtain stable Pickering emulsions. The rheology and stability of these o/w Pickering emulsions were systematically characterised using a rheometer, laser scanning confocal microscopy and tensiometer. The UV absorbance of the formulated emulsions was studied in time by UV/Vis spectrophotometry.
Results and Discussion:
Stable Pickering emulsions containing between 40 and 60 wt.% of silicone oil were formulated with 2 wt.% of silica particles (containing UV filters) in the aqueous phase. The droplet size was controlled by the silica nanoparticles concentration (with respect to the oil phase). The Pickering emulsions were stable against coalescence, creaming and Ostwald ripening and exhibited photoprotective properties similar to photoprotective sunscreens stabilized with surfactants and free organic UV filters with an in vitro SPF of about 30.
Conclusion:
Pickering emulsions with functionalized (nano)particles offer a new class of functional material. In this work, we show that such Pickering emulsions with nanoparticles not only provide full broadband UV protection but are also able to stabilize emulsions and constitute an excellent alternative to surfactant-free Pickering emulsion.
Pickering emulsions have recently gained much attention in the cosmetic formulation community because of their ability to stabilize emulsions such as sunscreens and they offer a promising alternative to classical surfactants, which are known to cause skin irritation. Pickering emulsions use solid (nano)particles with the key advantage to be functionalized. For instance, very recent advances in sunscreen formulation suggest using nanoparticles with encapsulated (organic) UV filters to optimize solar protection. In this work, we formulate and study surfactant-free sunscreen emulsions over a broad range of silicon oil concentrations, solely stabilized by silica nanoparticles (NPs). Our formulation provides good stability of the emulsion in time with good UV absorbance performance.
Methods used:
Silica particles containing the organic UV filters avobenzone and octocrylene were mixed with a model silicone oil phase to obtain stable Pickering emulsions. The rheology and stability of these o/w Pickering emulsions were systematically characterised using a rheometer, laser scanning confocal microscopy and tensiometer. The UV absorbance of the formulated emulsions was studied in time by UV/Vis spectrophotometry.
Results and Discussion:
Stable Pickering emulsions containing between 40 and 60 wt.% of silicone oil were formulated with 2 wt.% of silica particles (containing UV filters) in the aqueous phase. The droplet size was controlled by the silica nanoparticles concentration (with respect to the oil phase). The Pickering emulsions were stable against coalescence, creaming and Ostwald ripening and exhibited photoprotective properties similar to photoprotective sunscreens stabilized with surfactants and free organic UV filters with an in vitro SPF of about 30.
Conclusion:
Pickering emulsions with functionalized (nano)particles offer a new class of functional material. In this work, we show that such Pickering emulsions with nanoparticles not only provide full broadband UV protection but are also able to stabilize emulsions and constitute an excellent alternative to surfactant-free Pickering emulsion.