COSMETIC LIQUID CRYSTAL EMULSIONS CONTAINING BRAZILIAN VEGETABLE BUTTERS

Abstract
Emulsions containing vegetable butters have especially attractive properties in cosmetic technology. They are used as vehicle for topical application. Apart from that, the natural raw materials have pharmacological activity, increasing the necessity for the development of new delivery systems for them.
The function of liquid crystals has been investigated mainly due to studies on the cell membrane and interest in research in the development of cosmetic products applied to the skin. Of immense importance was the elucidation of the composition of the protein lipid envelope that surrounds the corneocytes of the skin that are organized in the lyotropic lamellar liquid crystalline state.
In this way, the formation of liquid crystal by the components of the formulation allows the incorporation of water-soluble, lipo-soluble and amphiphilic drugs within these layers. Therefore, they are structures of great importance for the cosmetic and pharmaceutical industries, having different functions and that we can call "intelligent cosmetic forms" for the application of cosmetic products, mainly due to the structural similarity with the lipid protein envelope of the stratum corneum.
This skin's protein lipid envelope decreases transepidermal water loss and keeps the skin soft to the touch, with accentuated features of rejuvenated skin. This research aims to develop cosmetic products containing vegetable butters, to study the formation of liquid crystal and physical chemical stability under different storage conditions.
Then, O/W emulsions containing vegetable butters were developed at a fixed surfactant ratio and observed the formation of liquid crystalline phases. Surfactant system was consisted by Steareth-2 and Ceteareth-5. Emulsions were prepared by the emulsion phase inversion (EPI) method, presenting high stability independent on the HLB value. Results indicate that this method could be employed to attain stable emulsions, even if the required HLB value is not known

摘要
含有植物脂膏的乳液在化妆品制备工艺中具备尤为优异的应用性能，可用作局部外用制剂的载体。此外，天然原料本身具有药理活性，这进一步提升了开发针对此类天然原料的新型递送系统的必要性。
液晶（liquid crystal）的相关功能研究主要源于细胞膜领域的探索，以及皮肤用化妆品开发的研究热情。阐明皮肤角质细胞周围以溶致层状液晶态有序排布的蛋白质脂质包膜的组成结构，具有极其重要的研究价值。
基于上述研究背景，化妆品配方组分可通过自组装形成液晶结构，从而将水溶性、脂溶性及两亲性药物包埋于各层间隙中。此类结构对化妆品与制药工业均具有重要意义，具备多重功能特性；且由于其与皮肤角质层的脂质蛋白质包膜结构高度相似，可将其称为化妆品应用场景下的智能化妆品剂型（intelligent cosmetic forms）。
这种皮肤的蛋白质脂质包膜可有效减少经皮水分流失，使皮肤触感柔软，并展现出显著的嫩肤效果。
本研究旨在开发含植物脂膏的化妆品配方，研究其液晶形成过程以及不同储存条件下的物理化学稳定性。
随后，本研究在固定表面活性剂比例的条件下制备了含植物脂膏的水包油（O/W）型乳液，并观察到液晶相的形成。所用表面活性剂体系由硬脂醇聚醚-2（Steareth-2）与鲸蜡硬脂醇聚醚-5（Ceteareth-5）组成。本研究采用相转变乳化法（Emulsion Phase Inversion, EPI）制备乳液，结果显示无论所需亲水亲油平衡（HLB）值是否已知，该方法均可制备出高稳定性的乳液。