Omotosho J A, Whateley T L, Law T K, Florence A T
J Pharm Pharmacol. 1986 Dec;38(12):865-70. doi: 10.1111/j.2042-7158.1986.tb03373.x.
The effect of the nature of the oil phase of w/o/w emulsions stabilized by interfacial complexation between span 80 (sorbitan mono-oleate) and albumin has been studied. The long-term stability of the systems has been assessed by photomicrography and by measuring the quantity of an internal marker (NaCl) remaining entrapped with time. The number of multiple oil drops and the diameters of the internal aqueous droplets were determined over 6 weeks, and the amounts of NaCl entrapped over the same period were followed. There were no significant changes in w/o/w emulsions prepared with a range of hydrocarbons (octane, dodecane, hexadecane, toluene and cyclohexane), indicating stable multiple emulsions. The release of NaCl and 5-fluorouracil (5-FU) separately entrapped in the internal aqueous phase of w/o/w emulsions was measured. Diffusion of the un-ionized species of 5-FU across the oil phase or through localized thin oil lamellae is the primary transport mechanism. In the presence of surface active agents, water is solubilized in inverse micelles which would possess the ability to solubilize other water-soluble components, such as NaCl and 5-FU. The mixed inverse micellar units of Span 80 and polysorbate (Tween) 80 therefore act as solute carriers across the liquid hydrocarbon membrane separating the two aqueous phases of the emulsions. The main factor in determining the differences in rates of release from the hydrocarbon emulsions appears to be the droplet size of the internal aqueous phase.
研究了由司盘80（山梨醇单油酸酯）与白蛋白之间的界面络合作用稳定的w/o/w乳液油相性质的影响。通过显微摄影和测量随时间截留的内部标记物（NaCl）的量来评估体系的长期稳定性。在6周内测定多次油滴的数量和内部水相液滴的直径，并跟踪同一时期截留的NaCl量。用一系列碳氢化合物（辛烷、十二烷、十六烷、甲苯和环己烷）制备的w/o/w乳液没有显著变化，表明形成了稳定的多重乳液。测量了分别截留于w/o/w乳液内部水相中的NaCl和5-氟尿嘧啶（5-FU）的释放情况。5-FU未电离物种穿过油相或通过局部薄油层的扩散是主要的传输机制。在表面活性剂存在下，水溶解在反胶束中，反胶束具有溶解其他水溶性成分（如NaCl和5-FU）的能力。因此，司盘80和聚山梨酯（吐温）80的混合反胶束单元充当溶质载体，穿过分隔乳液两个水相的液态烃膜。决定碳氢化合物乳液释放速率差异的主要因素似乎是内部水相的液滴大小。
