Lab色度系统对不同类型防晒化妆品效果评价的现场实验研究

目的 ]　研究采用Lab色度系统 (△E)评价不同类型防晒化妆品的防晒效果的可行性。　 方法 ]　选择 35名年轻女性 ,随机分为 4组 ,在颊部使用含不同防晒剂的化妆品 ,以仪器法测得 4种化妆品的防晒系数SPF值和APF值。用光谱光度计记录其在 9月份连续 1 7d进行 6h室外活动暴露前及暴露后第 1、3、4、7、9、1 4、1 7d其颊部的Lab色度系统△E变化情况。同时 ,采用SPSS多变量方差分析方法分析防晒剂MCX、Parsol1 789对人体皮肤的防护作用。　 结果 ]　 4种防晒化妆品的SPF和APF值分别为 1 .0、2 .4、6 .3、9.2 (SPF)和 1 .0、3 .9、2 .0、4 .6(APF)。暴露期间 ,4组自愿者的颊部脸色 (△E)均比暴露前明显增加。使用防晒剂MCX能有效地阻止在阳光辐射下的肤色变深 ;SPF值或APF值不能完全代表UVA、UVB对肤色综合效应的防护作用。　 结论 ]　Lab色度系统可以作为防晒化妆品防晒效果的评价指标 ,颊部是防晒化妆品人体试验合适的观察部位。

A field experimental study of assessing the effects of different sunscreen products by Lab color system

To study whether it was practical to use Lab color system to assess the efficacy of sunscreen products. Thirty five young women volunteers were randomly divided into four groups using different sunscreen products on their cheeks. Four sunscreen products with respective sun protection factors(SPF and APF) were tested for their capacity to block ultraviolet rays. In September volunteers had 6 hrs outdoor activities daily for 17 days. The changes of skin color at cheeks(△E) before exposure and after exposure for 1, 3, 4, 7, 9, 14 and 17 days were detected. The effects of sunscreens (MCX and Parsol 1789) were analyzed by SPSS. The values of SPF and APF of the four sunscreen products detected were 1.0, 2.4 , 6.3, 9.2(SPF) and 1.0, 3.9, 2.0, 4.6(APF) respectively. The values of Lab color system all increased during exposure. Usage of MCX could effectively block the deepening of skin color. SPF or APF value could not wholly represent the role of sunscreens in protecting skin color under the broad band UVA and UVB radiation. Conclusion] Lab color system can be used as index to assess quantitative protection function of sunscreens. Cheek is the most appropriate observing site of sunscreen' effect.