Department of Pharmaceutics, Faculty of Pharmacy, Kuwait University, Jabriya, Kuwait.
Med Princ Pract. 2011;20(6):509-13. doi: 10.1159/000329883. Epub 2011 Oct 4.
To investigate the ability of α-tocopherol acetate (TA) and α-tocopherol (T), widely used ingredients in cosmetics, to cross the epidermal barrier using the neonatal rat as a model.
The content of T and TA in four marketed products (A-D) and two experimental formulations (F1, F2) was investigated by HPLC. An in vitro permeation study was performed in neonatal rat epidermis using diffusion cells. In vivo permeation was studied in neonatal rats after repeated application of the products and analysis of T and TA in the stratum corneum/deeper skin layers.
Variable contents of TA were found in the marketed products (0.12-0.53%). No vitamin permeation was detected through the stratum corneum as in vitro biological barrier after 4 h. No detectable T and TA were seen in the in vivo permeation study in the epidermis. Variable degrees of drug penetration (4.3-12.6%) of the applied dose into the deeper skin layers were observed, depending on the formulation. In vivo application of TA-containing preparations did not result in any transformation of TA into T under the described experimental conditions.
TA and T exhibited variable skin penetration and TA did not transform into T under the experimental conditions. The data underscored the need for further studies to optimize such formulations to improve vitamin E transdermal permeation and eventually achieve the expected cosmetic/therapeutic outcome.
以新生大鼠为模型，研究广泛用于化妆品的醋酸生育酚（TA）和生育酚（T）穿过表皮屏障的能力。
采用 HPLC 法对四种市售产品（A-D）和两种实验制剂（F1、F2）中的 T 和 TA 含量进行了研究。采用扩散池对新生大鼠表皮进行体外渗透研究。对产品进行重复应用后，分析角质层/深层皮肤层中的 T 和 TA，研究其体内渗透情况。
市售产品中发现 TA 的含量不同（0.12-0.53%）。4 小时后，作为体外生物屏障，未检测到维生素透过角质层。在表皮的体内渗透研究中，未检测到 T 和 TA。根据制剂的不同，药物渗透到深层皮肤的程度（4.3-12.6%）也不同。在描述的实验条件下，TA 含量的制剂应用并未导致 TA 转化为 T。
TA 和 T 表现出不同的皮肤渗透性，并且在实验条件下 TA 不会转化为 T。这些数据强调需要进一步研究以优化此类制剂，以改善维生素 E 的经皮渗透，最终达到预期的美容/治疗效果。
