Engblom J
Food Technology, Lund University, Sweden.
Chem Phys Lipids. 1996 Dec 20;84(2):155-64. doi: 10.1016/s0009-3084(96)02633-3.
Biological effects of foreign substances are usually caused by their interaction within lipid bilayers with the membrane lipids. It is therefore desirable in many situations to determine the effects and the partition of xenobiotic substances, as well as drugs, added to amphiphile-water systems. Bicontinuous cubic liquid crystals provide three-dimensional isotropic matrices with symmetries easily obtained by X-ray diffraction, and were shown to be a useful tool for an initial investigation of the molecular properties possessed by a foreign substance. The concept is illustrated by adding the transdermal penetration enhancer Azone (n-dodecyl-caprolactam) to V2-phases in the glycerol monooleate (GMO)-water system. The weakly polar, water immiscible, Azone is known to favour reversed types of phases in liquid crystals. In the present investigation, Azone was shown to prefer the lipid bilayer interior, with about 19% anchored in the lipid-water interfacial region. Some dependence of its location on water concentration was indicated. The unexpected swelling behaviour of monoacylglycerols in water (L2-->L alpha-->V2) were postulated to result from the lipids changing their polar headgroup conformation, thus allowing for an increase in packing parameter upon increasing the water content.
外来物质的生物学效应通常是由它们在脂质双分子层中与膜脂的相互作用所引起的。因此，在许多情况下，确定添加到两亲物-水体系中的外源性物质以及药物的效应和分配是很有必要的。双连续立方液晶提供了具有易于通过X射线衍射获得的对称性的三维各向同性基质，并且已被证明是对外来物质所具有的分子特性进行初步研究的有用工具。通过在甘油单油酸酯（GMO）-水体系的V2相中添加透皮渗透促进剂氮酮（正十二烷基己内酰胺）来说明这一概念。已知弱极性、与水不混溶的氮酮有利于液晶中反转类型的相。在本研究中，氮酮显示出更倾向于脂质双分子层内部，约19%锚定在脂质-水界面区域。表明其位置对水浓度有一定依赖性。单酰基甘油在水中意外的膨胀行为（L2→Lα→V2）被推测是由于脂质改变了其极性头基构象，从而在增加水含量时允许堆积参数增加。
