Development of O/W Zinc Only sunscreen Formulation with high UV Protection index and high transparency of Clean beauty
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Presented by: Hyeon Seon Park
Abstract
Background
Recently, the U.S. government of Hawaii banned the distribution and sale of sunscreen containing organic sunscreen Oxybenzone and octinoxate as a result of a study that organic sunscreen causes "depression" of coral reefs. Therefore, interest in inorganic sunscreen is gradually increasing in the cosmetics industry. However, among inorganic sunscreen, ZnO dissociates from the water solvent due to its amphoteric nature, which can lead to a decrease in efficient UV protection due to stability problems caused by pH increase. Therefore, we tried to develop a new O/W suncare formulation suitable for the transparent and clean beauty trend as well as showing high UV protection effect using ZnO only.
Methods and Results
The three types of ZnO used in the experiment were coated with triethoxycaprylsilane, and the particle sizes were 15 nm (ZnO-15), 30 nm (ZnO-30), and 105 nm (ZnO-105), respectively, using the SEM. The UV protection effect was compared for the new O/W formulation in which the coated ZnO powder was applied 25% to the oil surface of sunscreen formulation. This new O/W formulation is a PEG, PPG, and silicone free formulation. As a result of measuring the UV protection efficacy of In-vitro and in-vivo, the UV protection efficacy of ZnO-15 with the smallest particle size was the highest at SPF36, PA9. . In addition, the white cast measurement was carried out with a color meter to confirm the W (White value) value. As a result, the formulation of ZnO-15 with the best UV protection index showed a value of 40.24. To reach the UV protection target index, an oil dispersion with an optimal composition selected for each particle size was prepared, and ZnOdis-15, ZnOdis-30 and ZnOdis-105 were added 25% to the flow of sunscreen prescription to prepare a stabilized O/W sunscreen formulation, and the UV protection index was measured. In addition, the composition ratio of maximally increasing the UV blocking efficiency was confirmed by mixing each ZnO-containing dispersion with different particle sizes. As a result, when the oil dispersion was simultaneously used as compared with only each powder, the UV protection index increased by 1 port (SPF2, PA3) or more, and when the ratio of ZnO oil dispersion was ZnOdis-15: ZnOdis-105=5:5 with different particle sizes, the best UV protection efficiency was SPF 38.8 and PA18. In addition, as a result of white cast measurement, transparent results were derived compared to when only powder was used with W=11.
Conclusion
This study confirmed the UV protection efficacy, degree of white cast, and stability of each particle size by applying ZnO powder and ZnO oil dispersion to O/W prescription. These findings suggest that it will meet the diverse needs of consumers who prefer clean beauty and will also help develop new sunscreen products that can respond to U.S. Island Ban regulations.
Background
Recently, the U.S. government of Hawaii banned the distribution and sale of sunscreen containing organic sunscreen Oxybenzone and octinoxate as a result of a study that organic sunscreen causes "depression" of coral reefs. Therefore, interest in inorganic sunscreen is gradually increasing in the cosmetics industry. However, among inorganic sunscreen, ZnO dissociates from the water solvent due to its amphoteric nature, which can lead to a decrease in efficient UV protection due to stability problems caused by pH increase. Therefore, we tried to develop a new O/W suncare formulation suitable for the transparent and clean beauty trend as well as showing high UV protection effect using ZnO only.
Methods and Results
The three types of ZnO used in the experiment were coated with triethoxycaprylsilane, and the particle sizes were 15 nm (ZnO-15), 30 nm (ZnO-30), and 105 nm (ZnO-105), respectively, using the SEM. The UV protection effect was compared for the new O/W formulation in which the coated ZnO powder was applied 25% to the oil surface of sunscreen formulation. This new O/W formulation is a PEG, PPG, and silicone free formulation. As a result of measuring the UV protection efficacy of In-vitro and in-vivo, the UV protection efficacy of ZnO-15 with the smallest particle size was the highest at SPF36, PA9. . In addition, the white cast measurement was carried out with a color meter to confirm the W (White value) value. As a result, the formulation of ZnO-15 with the best UV protection index showed a value of 40.24. To reach the UV protection target index, an oil dispersion with an optimal composition selected for each particle size was prepared, and ZnOdis-15, ZnOdis-30 and ZnOdis-105 were added 25% to the flow of sunscreen prescription to prepare a stabilized O/W sunscreen formulation, and the UV protection index was measured. In addition, the composition ratio of maximally increasing the UV blocking efficiency was confirmed by mixing each ZnO-containing dispersion with different particle sizes. As a result, when the oil dispersion was simultaneously used as compared with only each powder, the UV protection index increased by 1 port (SPF2, PA3) or more, and when the ratio of ZnO oil dispersion was ZnOdis-15: ZnOdis-105=5:5 with different particle sizes, the best UV protection efficiency was SPF 38.8 and PA18. In addition, as a result of white cast measurement, transparent results were derived compared to when only powder was used with W=11.
Conclusion
This study confirmed the UV protection efficacy, degree of white cast, and stability of each particle size by applying ZnO powder and ZnO oil dispersion to O/W prescription. These findings suggest that it will meet the diverse needs of consumers who prefer clean beauty and will also help develop new sunscreen products that can respond to U.S. Island Ban regulations.