|摘要: ||因台灣同時具有熱帶及亞熱帶的氣候特色，長年日射量高且長，在加上全世界因氟氯碳化物的使用，臭氧層遭受破害，使得紫外線到達地表量增加，且肌膚長時間暴露在此環境中時，會遭成肌膚傷害甚至病變的危機，所以防護化妝品 — 防曬產品的使用就更為重要。
研究利用 Span 80 / Tween 60 為乳化系統，並以 Isopropyl Palmitate、Finsolv TN、Cyclopentasiloxane 為基礎油脂，進行單一及混合油脂添加調製基礎乳液，所得配方產品再經 45℃ 加速老化後測定流變性質及黏度變化、粒徑分佈及相分離等物性，進而選出最佳基礎乳液。取此基礎乳液再進行防曬成分之添加調製成防曬產品。而防曬成分則運用最常見的 Octyl Methoxy Cinnamate (PMCX)、Octocrylene、4-Tert-Butyl Methoxy Dibenzoyl Methane (P1789)，進行單一及混合方式添加，除了探討防曬劑間的加成效能，並以 in vitro SPF 測定儀測定其 SPF 值，然而使用此儀器時有塗佈性的問題存在，並非每個人都能輕易上手。因此另利用紫外光/可見光光譜分析儀開發一套迅速且有相應關係存在的防曬評估方法。
經研究結果顯示，基礎乳液中混合式油脂的使用其物理性質較優於單一油脂的使用，且乳化系統之 HLB 值為 9.60 時為最佳，經加速老化後安定天數都可達到 60 天以上。而所得的防曬配方均具有切變減稀的流體性質，乳化粒徑大小在 10 μm 以內，安定性也可維持 60 天以上。
另外，SPF 有效性顯示，防曬劑成分濃度與 SPF 防護能力有一正比關係的存在，具有線性的表現，因此可從關係中估計防曬產品之 SPF 值。另外，在不同防曬組成中以兩種成分添加中 PMCX + P1789 的加成作用最明顯，但 SPF 安定性則 PMCX + P1789 之安定性最差。但當在配方中添加 Octocrylene 時，就能有減緩此安定性不佳的現象，且濃度用高效果越佳。在 SPF 數值檢測上，以 UV-Vis Spectrophotometer 及 Labsphere’s UV-1000S analyzer 兩種儀器方法檢測防曬配方所得的 r 值為 0.9980，顯示此方法是可行的，它可以快速的提供 SPF 檢測值，且對檢測人員的訓練時間短，也增加新產品在 SPF 有效性的鑑識速度並縮短研發時間。
Ozone layer depletion is to continue for several years due to the existing ozone depleting chemicals, such as a series of chlorofluorocarbon components, those are known to remain in the atmosphere. This is will result in the increasing amount of UV sunlight that reaches the earth’s surface. It is well known that an excessive exposure to UV radiation will cause wrinkling, premature aging of the skin, hyperpigmentation macules and even skin cancer. In general, the customary use of sunscreens in the condition of exposure is recommended in order to reduce significantly the level of UV irradiation. The well-known harmful effects of UV radiation have led the intensive development of sunscreen products.
The objectives of the present study were to formulate sunscreens, to determine their physical-chemical properties and to evaluate the influence of different filter combinations on their SPF (Sun Protection Factor) effectiveness.
In order to formulate sunscreen products, the mixture of Span 80 with Tween 60 at varying HLB values as emulsifies and three different oils - Isopropyl Palmitate, C12-15 Alkyl Benzoate, Cyclopentasiloxane as oil phase, were examined. And then Octyl Methoxy Cinnamate (PMCX), 4-Tert-Butyl Methoxy Dibenzoyl Methane (P1789) and Octocryene were approved UV filters. Each of them at varying levels was incorporated individually during the emulsification. Moreover, the different UV filters combinations at varying levels are also incorporated into the optimum emulsion with 9.60 of HLB during the production. As a result, a series of sunscreen products with different UV filters were obtained. Their physical-chemical properties and their effectiveness of SPF were determined instrumentally.
The results showed that all the emulsions without any UV filter have good storage stability at 45℃ for 60 days. Furthermore, when the mix emulsifier is with 9.60 of HLB and the mixture of three different oils is used as oil phase, the emulsion obtained has a more esthetic appearance which is an important feature for being a commercial product.
We have demonstrated that all the sunscreen products had pseudoplastic behavior which produces a coherent protective film covering the skin surface with evenly distributed UV filters. In addition, their storage stability is also up to 60 days at 45℃ accelerated test. On the other hand, SPF effectiveness of all the sunscreen products were measured by two different instruments, Labsphere UV-1000S transmittance analyzer (according to Food and Drug administration method) and UV-Vis Spectrophotometer (according to the spectrophotometric method of Robent M. Sayre). These results indicate that there was a good correlation between the two different determinations for the sunscreen formulations. The correlation confident of liner regression was 0.9981. Furthermore, the SPF effectiveness increases with the increase in amounts of UV filters make it possible to attain sunscreens with high SPF value and to result in synergistic effect on the sun protect efficacy. The sunscreen product containing a combination of PMCX with P1789 exhibits better synergistic effect than those with other combinations. However, it has a poor photostablity. Fortunately, the photo-stability can be improved by adding Octocryene at a higher level to it. Therefore, when sunscreen products are formulated, it is important for optimizing them to consider different filters combinations and the kinds of emulsifiers and the types of oils.