Shima Motohiro, Tanaka Miyono, Kimura Yukitaka, Adachi Shuji, Matsuno Ryuichi
Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kitashirakawaoiwake-cho, Sakyo, Kyoto 606-8502, Japan.
J Control Release. 2004 Jan 8;94(1):53-61. doi: 10.1016/j.jconrel.2003.09.008.
W/O/W emulsions are expected to protect bioactive substances from degradation by pancreatic enzymes. We investigated the enzymatic hydrolysis of the oil phase and release of a marker substance from the inner-aqueous phase to the outer-aqueous phase using an artificial digestive fluid. Octanoic acid triacylglycerol (C8TG) was used as the oil phase. W/O/W emulsions were prepared by two-step homogenization and succeeding membrane filtration. When the artificial digestive fluid containing lipase and gall was added to the emulsion, release of the marker substance from the inner-phase solution, oil-phase hydrolysis, and emulsion coalescence occurred in that order. When a coarse emulsion and 0.2- and 0.8-microm membrane-filtered fine emulsions were treated with the fluid for 1 h, the degrees of C8TG hydrolysis were 3.8%, 55% and 57%, the fractions of the marker substance released from the inner-water phase were 2.7%, 89% and 72%, and the median diameters of the oil droplets were changed from 32 to 23 microm, 0.71 to 27 microm, and from 2.2 to 26 microm, respectively. These results suggested that the diameter of the oil droplets in the W/O/W emulsion significantly affected the release profile of the marker loaded in the inner-water phase of the emulsion.
水包油包水型乳液有望保护生物活性物质不被胰酶降解。我们使用人工消化液研究了油相的酶促水解以及标记物质从内水相向外水相的释放情况。辛酸三酰甘油（C8TG）用作油相。通过两步均质化和后续的膜过滤制备水包油包水型乳液。当向乳液中加入含有脂肪酶和胆汁的人工消化液时，标记物质从内相溶液中的释放、油相水解和乳液聚结按此顺序发生。当用该消化液处理粗乳液以及经0.2微米和0.8微米膜过滤的细乳液1小时时，C8TG的水解程度分别为3.8%、55%和57%，从内水相中释放的标记物质的比例分别为2.7%、89%和72%，油滴的中位直径分别从32微米变为23微米、从0.71微米变为27微米以及从2.2微米变为26微米。这些结果表明，水包油包水型乳液中油滴的直径显著影响乳液内水相中负载的标记物的释放情况。
