微乳液 (Microemulsion) 為化粧品載體之一，是熱力學穩定系統且製備方法簡單，具有很小的液滴大小 (5-100 nm)，能提高有效成份的經皮吸收效果。本研究主要目的為探討含維生素 C (AA)、維生素 C 醣苷 (AA2G) 及 3 氧乙基維生素 C (3OEAA) 之微乳液的製備及物理化學安定性質。製備混合型界面活性劑及單一型界面活性劑之微乳液。維生素 C 、維生素 C 醣苷及 3 氧乙基維生素 C 各別添加在微乳液中，並藉由 HPLC 、動態光散射分析儀、 pH 值、黏度及折射率來評估其安定性。以擬三相圖繪製微乳液形成之範圍。以靜態擴散裝置及豬皮測定體外經皮吸收，並與傳統乳液進行比較。結果顯示 L 型及 LS 型的平均粒徑分別為 100 nm 及 40 nm。LS 型微乳液比 L 型較穩定。 AA2G 在兩種微乳液配方中皆很穩定。以 LS 型微乳液皮膚穿透最高且高於傳統乳液。 Microemulsions (MEs) are carrier systems for cosmetics, which are thermodynamically stable, ease of preparation, with very small droplet size (5-100 nm), and can enhance skin permeation of the loaded substances. The aim of this work was to investigate the preparation and physicochemical properties of ascorbic acid (AA), ascorbic acid 2-glucoside (AA2G) and 3-o-ethyl ascorbic acid (3OEAA) in MEs. MEs of surfactant mixed type (LS type) and single surfactant type (L type) were prepared. AA, AA2G and 3OEAA were added respectively to the MEs and their stability were evaluated by HPLC, Dynamic Light Scattering, pH meter, viscosity and refractive index. MEs existence ranges were identified through the construction of the pseudo-ternary phase diagram. In vitro transdermal penetration was evaluated by Franz diffusion cells with pig-skin, and compared with conventional emulsion. Result shows that the mean droplet size of type L and type LS are 100nm and 40 nm, respectively. LS type ME was stable than L type. AA2G was stable in both types of ME. LS type ME with the highest skin penetration than conventional emulsion.
