Research Platform Characterisation of Drug Delivery Systems on Skin and Investigation of Involved Mechanisms, University of Vienna, Vienna, Austria.
Eur J Pharm Biopharm. 2012 Aug;81(3):557-62. doi: 10.1016/j.ejpb.2012.04.003. Epub 2012 Apr 27.
Microemulsions are thermodynamically stable, colloidal drug delivery systems. This study presents the first substantiated comparison of natural, skin-compatible and biodegradable surfactants in terms of their suitability to form isotropic microemulsions and their skin interaction. Pseudoternery phase diagrams were constructed for lecithin, sucrose laurate and alkylpolyglycoside as single surfactants. Moreover, also mixed surfactant films of lecithin and alkylpolyglycoside as well as lecithin and sucrose laurate were tested. Large isotropic areas could be identified for lecithin, sucrose laurate and lecithin-sucrose laurate. One defined composition was chosen from the pseudoternery phase diagram, prepared with all investigated surfactants and 1:1 surfactant mixtures, respectively, and analysed for their effect on the stratum corneum on a molecular level by ATR-FTIR. Significantly higher frequency values of the symmetric and asymmetric CH(2)-stretching bands compared to the control were recorded for all microemulsions, indicating a hexagonal arrangement of the lipid chains. A similar trend was observed for the lateral packing of the alkyl chains as suggested by the shift of the CH(2)-scissoring bands. Moreover, diffusion cell experiments using porcine skin were performed with the two model drugs flufenamic acid and fluconazole. In both cases, the lecithin-based microemulsions showed the highest permeation rates followed by the alkylpolyglycoside-lecithin microemulsions.
微乳液是热力学稳定的胶体药物传递系统。本研究首次对天然、与皮肤相容和可生物降解的表面活性剂进行了实质性比较，评估了它们形成各向同性微乳液的能力及其与皮肤的相互作用。构建了卵磷脂、月桂酰基蔗糖酯和烷基糖苷作为单一表面活性剂的伪三元相图。此外，还测试了卵磷脂和烷基糖苷以及卵磷脂和月桂酰基蔗糖酯的混合表面活性剂膜。可以为卵磷脂、月桂酰基蔗糖酯和卵磷脂-月桂酰基蔗糖酯确定大的各向同性区域。从伪三元相图中选择一个定义的组成，分别用所有研究的表面活性剂和 1:1 表面活性剂混合物制备，并通过 ATR-FTIR 分析它们对角质层的分子水平影响。与对照相比，所有微乳液的对称和不对称 CH(2)-伸缩带的频率值显著升高，表明脂质链呈六方排列。CH(2)-剪断带的位移表明烷基链的侧向堆积也呈现出类似的趋势。此外，还使用猪皮进行了扩散池实验，研究了两种模型药物氟芬那酸和氟康唑。在这两种情况下，基于卵磷脂的微乳液表现出最高的渗透率，其次是烷基糖苷-卵磷脂微乳液。
