Gupta V K, Zatz J L, Rerek M
Organon Inc., West Orange, New Jersey 07052, USA.
Pharm Res. 1999 Oct;16(10):1602-7. doi: 10.1023/a:1018916907263.
The objectives of this study were to develop an in vitro model for studying sunscreen permeation in skin, and evaluate the influence of formulation differences.
The sunscreens studied were two of the most widely used agents, octyl methoxycinnamate (OMC) and benzophenone-3. Preparations containing radiolabeled actives were applied to micro-Yucatan pig skin dermatomed to a thickness of 250-300 microm as a finite dose in a flow-through diffusion system. At the end of each experiment the amounts removed by washing, retained inside stratum corneum (SC) and penetrated into receptor and viable skin were determined.
The two sunscreens reached a peak level in SC within an hour. Benzophenone-3 penetrated skin to a greater extent than OMC. The opposite was true when comparisons of SC retention were made. The ratio of retained to penetrated amount of sunscreens from a hydroalcoholic formulation at the end of 10 hours was higher when the sunscreens were present together than alone.
Despite the highly lipophilic nature of sunscreens, particularly OMC, SC is the rate limiting skin layer for penetration. Penetration and SC retention were formulation dependent. The ratio of SC content to the amount penetrated is a useful tool for evaluating sunscreen permeation.
本研究的目的是建立一种体外模型，用于研究防晒霜在皮肤中的渗透情况，并评估配方差异的影响。
所研究的防晒霜是两种最广泛使用的成分，桂皮酸盐（OMC）和二苯甲酮-3。将含有放射性标记活性成分的制剂以有限剂量应用于厚度为250-300微米的微型尤卡坦猪皮肤，置于流通扩散系统中。在每个实验结束时，测定通过洗涤去除的量、保留在角质层（SC）内的量以及渗透到受体和活皮肤中的量。
两种防晒霜在1小时内达到角质层中的峰值水平。二苯甲酮-3比桂皮酸盐渗透到皮肤中的程度更大。在比较角质层保留量时则相反。在10小时结束时，当两种防晒霜同时存在时，来自水醇制剂的防晒霜保留量与渗透量的比率高于单独使用时。
尽管防晒霜具有高度亲脂性，尤其是桂皮酸盐，但角质层是渗透的限速皮肤层。渗透和角质层保留取决于配方。角质层含量与渗透量的比率是评估防晒霜渗透的有用工具。
