Kim Y H, Higuchi W I, Herron J N, Abraham W
Department of Pharmaceutics, University of Utah, Salt Lake City 84112.
Biochim Biophys Acta. 1993 May 14;1148(1):139-51. doi: 10.1016/0005-2736(93)90171-u.
Previously, the action of the short chain n-alkanols (from C1 to C5) and isopropanol as possible enhancers on the transport of lipophilic and polar/ionic permeants across hairless mouse skin was investigated. In the present study, the steady-state fluorescence anisotropy was measured as a means of estimating the changes in fluidity caused by the n-alkanols at different depths in the stratum corneum lipid liposomes (SCLL). Some selected experiments with the distearoylphosphatidylcholine (DSPC)/distearoylphosphatidic acid (DSPA) liposomes were performed for relative comparisons. The effects of the n-alkanols on polarity sensitive parameters such as fluorescence lifetimes, fluorescence quantum yield ratios, and emission maxima were studied in the SCLL. The polarity of the bilayer decreased as the fluorescent probe was placed closer to the bilayer center and the n-alkanols did not alter this gradient. Assessment of the depth-dependent effects of the n-alkanols using SCLL showed that most of the significant changes in fluidity induced by the n-alkanols were observed at intermediate depths (C2-C9) and there was little or no increase in fluidity in the deep hydrophobic region close to the bilayer center. These results suggest that the short chain n-alkanols work as effective 'fluidizing' agents at the intermediate depths (C2-C9) in the bilayer.
此前，研究了短链正烷醇（从C1到C5）和异丙醇作为可能的增强剂对亲脂性和极性/离子性渗透剂跨无毛小鼠皮肤转运的作用。在本研究中，测量稳态荧光各向异性，作为估计正烷醇在角质层脂质体（SCLL）不同深度引起的流动性变化的一种方法。对二硬脂酰磷脂酰胆碱（DSPC）/二硬脂酰磷脂酸（DSPA）脂质体进行了一些选定的实验以作相对比较。在SCLL中研究了正烷醇对极性敏感参数如荧光寿命、荧光量子产率比和发射最大值的影响。随着荧光探针靠近双层中心，双层的极性降低，且正烷醇并未改变这种梯度。使用SCLL评估正烷醇的深度依赖性效应表明，正烷醇引起的流动性的大多数显著变化出现在中间深度（C2 - C9），而在靠近双层中心的深疏水区域，流动性几乎没有增加或没有增加。这些结果表明，短链正烷醇在双层的中间深度（C2 - C9）起有效的“流化”剂作用。
