背景:尽管角蛋白水解产物已成为头发和指甲化妆品中的标准成分,关于角蛋白水解物的保湿效果的研究没有出现在当代文献中。
目的:为了测试在软膏基质中添加角蛋白水解物是否会增加皮肤的水合作用并改善皮肤屏障功能,或减少经表皮水分流失。
方法:制备含有2%,4%,和6%角蛋白水解产物(基于软膏基质的重量)。通过测量皮肤水合作用来测试角蛋白水解产物的保湿性能,经表皮水分流失和皮肤pH值;测量间隔为1、2、3、4、24和48小时。对10名女性进行了测试。
结果:关于水合作用,在软膏基质中加入2%的角蛋白水解物是最佳的,角质层的水合作用增加了14%-23%。对于经表皮失水,在软膏基质中加入4%KH是优先的,因为这触发了26%-46%的跨表皮水分流失减少。
结论:角蛋白水解物充当湿润剂(其将来自表皮下层的水结合到角质层)以及闭塞剂(其减少经表皮水分流失)。角蛋白水解产物的高度有利的性质归因于角蛋白水解产物分子量的广泛分布;低分子量部分容易穿透SC,而高分子量部分在表皮上形成保护膜。即使在储存6个月后,向软膏基质中添加角蛋白水解产物也不会引起相分离。
BACKGROUND: Although keratin hydrolysates have become established as standard components in hair and nail cosmetics, studies on the moisturizing effects of keratin hydrolysates do not appear among contemporary literature.
OBJECTIVE: To test if adding keratin hydrolysate into an ointment base increases hydration of the skin and improves skin barrier function, or diminishes trans-epidermal water loss.
METHODS: Formulations were prepared containing 2%, 4%, and 6% keratin hydrolysates (based on weight of the ointment base). The moisturizing properties of keratin hydrolysates were tested by measuring skin hydration, trans-epidermal water loss and skin pH; measurements were carried out at intervals of 1, 2, 3, 4, 24, and 48 h. Testing was conducted on 10 women.
RESULTS: As regards hydration, adding 2% keratin hydrolysate to the ointment base is optimal, as an increase of 14%-23% occurs in hydration of the stratum corneum. For trans-epidermal water loss, adding 4% KH to the ointment base is preferential, as this triggers a 26%-46% decrease in trans-epidermal water loss.
CONCLUSIONS: Keratin hydrolysate acts as a humectant (it binds water from lower layers of the epidermis to the stratum corneum) as well as an occlusive (it reduces trans-epidermal water loss). The highly favorable properties of keratin hydrolysates are attributed to the wide distribution of keratin hydrolysates molecular weights; low-molecular weight fractions easily penetrate the SC, while high-molecular weight fractions form a protective film on the epidermis. Adding keratin hydrolysates to the ointment base did not cause phase separation even after 6 mo storage.