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首页> 外文期刊>European journal of pharmaceutical sciences >Adaptation and optimization of the emulsification-diffusion technique to prepare lipidic nanospheres.
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Adaptation and optimization of the emulsification-diffusion technique to prepare lipidic nanospheres.

机译：乳化扩散技术的适应和优化，以制备脂质纳米球。

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In this study, the emulsification-diffusion method traditionally used to prepare polymeric nanoparticles was adapted to obtain lipidic nanospheres (LN) using four model lipids. The method consists of dissolving the lipid in a partially water-miscible solvent (previously saturated with water) at room temperature or at controlled temperature depending on lipid solubility. This organic phase is emulsified in an aqueous solution of a stabilizing agent (saturated with solvent) by conventional stirring at the same temperature used to dissolve the lipid. This oil-in-water emulsion is then diluted with an excess of water at controlled temperature in order to provoke the diffusion from the internal phase into the external phase thereby causing lipid aggregation in the form of LN. This new approach for the preparation of LN has clear advantages over the existing methods, namely: (i) it is efficient and versatile; (ii) easy implementation and scaling up (with no need of high energy sources); (iii) high reproducibility and narrow size distribution; (iv) less physical stress (i.e., long exposure to high temperatures and to mechanical dispersion); (v) it is not necessary to dissolve the drug in the melted lipid. The selection of the water-miscible solvent and the stabilizers are critical parameters to obtain lipidic particles in the nanometric range. In general, solvents with high water miscibility and stabilizers able to form stable emulsions are preferred. The results demonstrated that it was possible to reduce the particle size by increasing the process temperature, the stirring rate, the amount of stabilizer, and by lowering the amount of lipid. Control of the preparative variables allowed to obtain LN with diameters under 100 nm. It was found that the influence of preparative parameters was associated with a mechanism based on a physicochemical instability. In this sense, it is suggested that the rapid solvent diffusion produces regions of local supersaturation near the interface, and LN are formed due tothe ensuing interfacial phase transformations and lipid aggregation that occur in these interfacial domains. In terms of stability, only poly(vinyl alcohol) (PVAL) was able to preserve the physical stability of the dispersion for long periods after preparation. This effect was attributed to the ability of PVAL chains to form a strongly attached layer on the nanoparticle surface with an excellent repulsion effect.
机译：在这项研究中，传统上用于制备聚合物纳米粒子的乳化扩散方法适用于使用四种模型脂质获得脂质纳米球（LN）。该方法包括根据脂质的溶解度，在室温或受控温度下将脂质溶解在部分与水混溶的溶剂中（预先用水饱和）。通过常规搅拌在与溶解脂质相同的温度下，在稳定剂（用溶剂饱和）的水溶液中乳化该有机相。然后在控制的温度下用过量的水稀释这种水包油乳剂，以引起从内相到外相的扩散，从而导致脂质以LN形式聚集。与现有方法相比，这种制备LN的新方法具有明显的优势，即：（i）它高效且通用; （ii）易于实施和扩大规模（不需要大量能源）; （iii）高重复性和窄尺寸分布; （iv）较小的物理应力（即，长时间暴露于高温和机械分散状态）; （v）没有必要将药物溶解在熔化的脂质中。与水混溶的溶剂和稳定剂的选择是获得纳米级脂质颗粒的关键参数。通常，优选具有高水混溶性的溶剂和能够形成稳定乳液的稳定剂。结果表明，可以通过提高工艺温度，搅拌速率，稳定剂的量和降低脂质的量来减小粒度。通过控制制备变量，可以获得直径小于100 nm的LN。发现制备参数的影响与基于物理化学不稳定性的机制有关。从这个意义上讲，这表明溶剂的快速扩散会在界面附近产生局部过饱和的区域，并且由于在这些界面域中发生界面相变和脂质聚集而形成了LN。在稳定性方面，仅聚乙烯醇（PVAL）能够在制备后长时间保持分散体的物理稳定性。该作用归因于PVAL链在纳米颗粒表面上形成具有优异排斥作用的牢固附着层的能力。

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