Sun-protective products are facing increasing challenges today by the regulation restrictions of each country, the ocean ecology impact by UV-filter, and the consumer’s demand for more comfortable sensory experience, as well as higher sun-protective efficiency. In this study, two approaches were investigated for reducing the environmental impact of UV-filter. One is decreasing the dosage amount of UV-filter in formulation through enhancing its sun-protective performance, the other is keeping the amount of UV-filter on skin through enhancing water-resistant properties. Since several studies indicate that emulsifier can influence the sun-protective performance, 100% natural polyglycerol emulsifiers were chosen as the key ingredients in emulsion formulation to achieve the target.
First, polyglycerol emulsifiers were evaluated as a SPF booster to reduce the UV-filter ratio in formulation while retaining the same efficiency. The SPF of sun-protective formulation by commercial PEG-based emulsifiers and polyglycerol emulsifiers were compared by the in-vitro SPF measurement method. The polyglycerol-10 ester-based formulation provides 20% higher SPF value than that in polysorbate-based formulation. Secondly, the water-resistant properties were also investigated to determine the likely influence to ocean ecology of sun-protective formulations with polyglycerol emulsifier. In the water-resistant experiment, polyglycerol-10 ester-based formulation can provide up to 50% water resistance ability, which reduces the UV-filter releasing tendency to the environment through water activities.
The increasing SPF and water-resistant abilities of polyglycerol emulsifiers were also verified. From the view of environmental protection, applying 100% natural polyglycerol ester in the formulation can reduce the dosage rate of UV-filter and still maintains the same sunlight protective ability. The lower treat rate in formulation can further reduce the amount of UV-filter released to the environment.