Ruan G, Ng J-K, Feng S-S
Department of Chemical and Environmental Engineering, National University of Singapore, 10 Kent Ridge Crescent, 119260, Singapore.
J Microencapsul. 2004 Jun;21(4):399-412. doi: 10.1080/02652040410001729214.
The double emulsion process has commonly been applied to encapsulate water-soluble bioactive agents into polymeric microspheres. However, the integrity of many of these agents may be destroyed by the highly energetic procedures such as sonication that are routinely used to produce stable water-in-oil (w/o) emulsion. The aim of this research was to pursue the possibility of replacing the sonication by a mild emulsification procedure such as vortex mixing, with the use of certain materials to help to obtain stable w/o emulsion. The following materials were examined: poly(lactide-co-ethylene glycol) (PELA) as the polymer, ethyl acetate and acetone as the solvents, poly(vinyl alcohol) (PVA) and d-alpha tocopheryl polyethylene glycol 1000 succinate (Vitamin E TPGS) as the emulsifiers in w/o emulsion. The experimental results, with human serum albumin (HSA) as the encapsulated agent, showed that, when vortex mixing was used, these materials could significantly improve w/o emulsion stability and help to obtain satisfactory encapsulation effects, i.e. high encapsulation efficiency (EE) and low initial release burst. A delicate structure, i.e. liposomes, which is very sensitive to sonication, was then incorporated into microspheres by the 'modified double emulsion process'. It was found that the liposomes were intact and the encapsulation effects were good. Therefore, it can be concluded that the modified double emulsion process could be advantageous for the encapsulation of delicate substances.
复乳法通常用于将水溶性生物活性剂包封到聚合物微球中。然而，许多这类活性剂的完整性可能会被常规用于制备稳定油包水（w/o）乳液的高能程序（如超声处理）破坏。本研究的目的是探索用温和的乳化程序（如涡旋混合）取代超声处理的可能性，并使用某些材料来帮助获得稳定的w/o乳液。研究了以下材料：聚（丙交酯-共-乙二醇）（PELA）作为聚合物，乙酸乙酯和丙酮作为溶剂，聚乙烯醇（PVA）和d-α生育酚聚乙二醇1000琥珀酸酯（维生素E TPGS）作为w/o乳液中的乳化剂。以人血清白蛋白（HSA）作为包封剂的实验结果表明，当使用涡旋混合时，这些材料可显著提高w/o乳液的稳定性，并有助于获得令人满意的包封效果，即高包封率（EE）和低初始释放突释。然后通过“改良复乳法”将对超声处理非常敏感的精细结构（即脂质体）掺入微球中。结果发现脂质体完整且包封效果良好。因此，可以得出结论，改良复乳法对于包封精细物质可能具有优势。
