防曬乳在Span 80/Tween 60系統中之貯存安定性與SPF值有效性評估

Study on Stability and SPF Effectiveness of Sunscreens with Span80/Tween60

利用Span 80/Tween 60為乳化系統，並選擇三種最常見的防曬成分：Octyl Methoxy Cinnamate（PMCX）、Octocrylene（OCT）、及4-Tert-Butyl Methoxy Dibenzoyl Methane（P1789），進行單一及混合方式添加，製備一系列含不同防曬成分的防曬乳產品。所得防曬產品再經45℃加速老化後測定流變性質、黏度變化及相分離等各項物性以及利用Labsphere's UV-1000S測定SPF值（sun Protection Factor），進而觀察不同防曬成份對SPF之影響與防曬成份間的加成作用對SPF值之貢獻。經實驗結果顯示，所得的防曬產品均具有切變減稀（shear thinning）的流體性質，安定性也可維持60天以上並仍然具有優質乳液產品外觀。另外，SPF有效性顯示，防曬劑成分的濃度與SPF防護能力有一正比關係存在，單一防曬成份添加的結果，其線性相關係數（correlation coefficient, r）較佳，範圍在0.9800~0.9876之間。實驗結果已獲得最佳的防曬乳產品之配方，除了具有優質乳液產品外觀及好的應用性質外，也具備高SPF值的防護能力。

Using the mixture of Span 80 with Tween 60 as emulsifies and three approved UV filters-Octyl Methoxy Cinnamate （PMCX）, 4-Tert-Butyl Methoxy Dibenzoyl Methane （P1789） and Octocryene formulated a series of sunscreen products including different UV filters combinations at varying levels. These sunscreen products are characterized by rheological measurement, stability tests and SPF efficacy evaluation, It was found that the sunscreens have an aesthetic performance and their storage stability were up to 60 days at 45℃. The effect of UV filters on rheological behavior was examined. It was shown that all the sunscreen products formulated exhibited shear thinning behavior before and after accelerating aging test. In addition, SPF effectiveness was measured by Labsphere's UV-1000S transmittance analyzer （according to Food and Drug administration method）. These results indicated that there was a good linear correlation （SPF value vs concentration） for the sunscreens with only one kind of UV filter. The correlation coefficient of liner regression was the range of 0.9800~0.9876. Obviously, the SPF effectiveness increases with the increase in amounts of UV filters. Furthermore, a combination of two or more UV filters incorporated in a sunscreen product make it possible to result in synergistic effect on the sun protect efficacy. Therefore, when sunscreen products are formulated, it is important for optimizing them to consider different filters combinations and the right surfactants. An elegant suncream with both high SPF and good spreadability was obtained.