Treffel P, Gabard B
Department of Biopharmacy, Spirig AG, 4622 Egerkingen, Switzerland.
Pharm Res. 1996 May;13(5):770-4. doi: 10.1023/a:1016012019483.
In order to improve our knowledge on the efficacy and safety of sunscreen products, we measured the skin penetration profiles of ultra-violet (UV) filters in vitro and in vivo, and the corresponding sun protection factors (SPF) from two vehicles (an O/W emulsion-gel and petroleum jelly).
The UV filters tested were oxybenzone (5%, A), 2-ethylhexyl 4-methoxycinnamate (7.5%,B), and 2-ethylhexylsalicylate (3%,C). Two mg/cm(2) were applied for 2 min to 6 h. In vitro penetration measurements were performed with static diffusion cells. In vivo, horny layer concentrations were measured after stripping and the SPF evaluated as recommended by the COLIPA-guidelines.
Significant differences between vehicles were noticed in vitro as well as in vivo. In vitro, the emulsion-gel generated higher epidermal concentrations than petroleum jelly. Values at 6 h, expressed as percent of the applied dose for A, B, and C were 4, 9, and 7% for the emulsion-gel and 2, 1, and 2% for petroleum jelly. An opposite trend was noticed, mainly for A, in the deeper skin layers with concentrations of 2% in the dermis and 5% in the receptor fluid for petroleum jelly and 0.6% and 1% for the emulsion-gel respectively. In vivo, for each UV filter, maximal stratum corneum levels (15 strips) were obtained at 0.5 h with percentages of the applied doses of 50% for the emulsion-gel and 15 percent for petroleum jelly. SPFs, measured 0.5 h after application amounted to 14 for the emulsion-gel and 5 for petroleum jelly, and decreased in both cases by a factor 2.2 after removal of non penetrated product.
These preliminary results demonstrated that UV filters penetration and retention as well as expected SPF could be optimized by a suitable vehicle.
为提高我们对防晒产品功效和安全性的认识，我们在体外和体内测量了紫外线（UV）滤光剂的皮肤渗透情况，以及两种基质（水包油乳液凝胶和凡士林）相应的防晒系数（SPF）。
所测试的紫外线滤光剂为二苯甲酰甲烷（5%，A）、桂皮酸盐（7.5%，B）和水杨酸辛酯（3%，C）。每平方厘米涂抹2毫克，涂抹2分钟至6小时。体外渗透测量使用静态扩散池进行。在体内，去除角质层后测量角质层浓度，并按照COLIPA指南的建议评估SPF。
在体外和体内均发现不同基质之间存在显著差异。在体外，乳液凝胶产生的表皮浓度高于凡士林。6小时时，以A、B和C的给药剂量百分比表示，乳液凝胶中A、B和C的值分别为4%、9%和7%，凡士林中分别为2%、1%和2%。在更深的皮肤层中观察到相反的趋势，主要是对于A，凡士林在真皮中的浓度为2%，在接受液中的浓度为5%，而乳液凝胶分别为0.6%和1%。在体内，对于每种紫外线滤光剂，在0.5小时时获得最大角质层水平（15次剥离），乳液凝胶的给药剂量百分比为50%，凡士林为15%。涂抹后0.5小时测量的SPF，乳液凝胶为14，凡士林为5，去除未渗透产品后，两种情况均下降了2.2倍。
这些初步结果表明，通过合适的基质可以优化紫外线滤光剂的渗透、保留以及预期的SPF。
