氮酮对鼠角质层角蛋白作用的光谱证据

Spectroscopic Evidence of Azone Effect on the Keratin in Mouse Stratum Corneum

应用 1 3C NMR和 ATR-FTIR为测试手段 ,探讨角蛋白的分子运动自由度与堆积结构 ,以及氮酮对鼠角质层角蛋白的作用 .经氮酮处理后 ,角蛋白主侧链碳的自旋晶格弛豫时间 t1 从 7.9,8.2和 2 .1 s分别减小到 5 .4,3 .6和 1 .6s,表明氮酮作用加快了角蛋白所有碳的运动 ,获得了氮酮对鼠角质层角蛋白作用的确凿证据 .同时 ,ATR-FTIR结果显示 ,经氮酮处理后 ,角蛋白的酰胺吸收峰 带的峰位从 1 5 44.7cm- 1 向低波数位移到 1 5 41 .4cm- 1 .结果表明氮酮可使部分角蛋白从α-螺旋型结构向β-折叠型结构和无规则卷曲型结构转变 ,导致角蛋白的堆积结构疏松 。

Chemical enhancers are widely employed to overcome the skin barrier in transdermal drug delivery systems. The penetration mechanism of chemical enhancers is the key point to develop a new transdermal drug delivery system. Azone is a common chemical enhancer and could make the stratum corneum(SC) lipid fluidization. However the protein also contributes to the skin barrier. Transport of large molecules was blocked by the keratin matrix even with an aqueous lipid pathway under a high-voltage pulsing. In this paper the effects of azone on the keratin in the mouse SC were investigated by determination of the molecular mobility and secondary structure of keratin. 13C NMR spectroscopy recorded a decreased spin-lattice relaxation time of keratin(t 1) for the carbon in the main and graft chain when treated with azone. ATR-FTIR spectra showed that amide Ⅱ absorption peak of keratin shifted from 1 544.7 to 1 541.4 cm -1 after the treatment with azone. It was concluded that azone could change the keratin conformation structure partially from α-helix to β-sheet or random coil, leading to a loose keratin structure, therefore reduced the drug transdermal delivery barrier.