Morais Jacqueline M, Rocha-Filho Pedro A, Burgess Diane J
Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, Storrs, CT 06269, USA.
Langmuir. 2009 Jul 21;25(14):7954-61. doi: 10.1021/la9007125.
A novel method of preparation of water-in-oil-in-micelle-containing water (W/O/W(m)) multiple emulsions using the one-step emulsification method is reported. These multiple emulsions were normal (not temporary) and stable over a 60 day test period. Previously, reported multiple emulsion by the one-step method were abnormal systems that formed at the inversion point of simple emulsion (where there is an incompatibility in the Ostwald and Bancroft theories, and typically these are O/W/O systems). Pseudoternary phase diagrams and bidimensional process-composition (phase inversion) maps were constructed to assist in process and composition optimization. The surfactants used were PEG40 hydrogenated castor oil and sorbitan oleate, and mineral and vegetables oils were investigated. Physicochemical characterization studies showed experimentally, for the first time, the significance of the ultralow surface tension point on multiple emulsion formation by one-step via phase inversion processes. Although the significance of ultralow surface tension has been speculated previously, to the best of our knowledge, this is the first experimental confirmation. The multiple emulsion system reported here was dependent not only upon the emulsification temperature, but also upon the component ratios, therefore both the emulsion phase inversion and the phase inversion temperature were considered to fully explain their formation. Accordingly, it is hypothesized that the formation of these normal multiple emulsions is not a result of a temporary incompatibility (at the inversion point) during simple emulsion preparation, as previously reported. Rather, these normal W/O/W(m) emulsions are a result of the simultaneous occurrence of catastrophic and transitional phase inversion processes. The formation of the primary emulsions (W/O) is in accordance with the Ostwald theory ,and the formation of the multiple emulsions (W/O/W(m)) is in agreement with the Bancroft theory.
报道了一种采用一步乳化法制备含胶束水包油包水（W/O/W(m)）多重乳液的新方法。这些多重乳液是正常（非暂时）的，并且在60天的测试期内保持稳定。此前，通过一步法报道的多重乳液是在简单乳液的转相点形成的异常体系（在奥斯特瓦尔德理论和班克罗夫特理论中存在不相容性，通常这些是O/W/O体系）。构建了拟三元相图和二维过程-组成（相转变）图，以协助进行过程和组成优化。所使用的表面活性剂为聚乙二醇40氢化蓖麻油和脱水山梨醇油酸酯，并对矿物油和植物油进行了研究。物理化学表征研究首次通过实验表明了超低表面张力点在通过相转变过程一步形成多重乳液中的重要性。尽管此前已推测过低表面张力的重要性，但据我们所知，这是首次实验证实。此处报道的多重乳液体系不仅取决于乳化温度，还取决于组分比例，因此乳液相转变和相转变温度都被认为可以充分解释它们的形成。因此，据推测这些正常多重乳液的形成并非如先前报道的那样是简单乳液制备过程中（在转相点）暂时不相容的结果。相反，这些正常的W/O/W(m)乳液是灾难性和过渡性相转变过程同时发生的结果。初级乳液（W/O）的形成符合奥斯特瓦尔德理论，而多重乳液（W/O/W(m)）的形成符合班克罗夫特理论。
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