Chouinard F, Buczkowski S, Lenaerts V
Glaxo Canada Inc., Mississauga, Canada.
Pharm Res. 1994 Jun;11(6):869-74. doi: 10.1023/a:1018938026615.
Nanocapsules of poly(isobutylcyanoacrylate) and poly(isohexylcyanoacrylate) were prepared by addition of the monomer to an organic phase and subsequent mixing of the organic phase to an aqueous phase containing poloxamer 188, 238 or 407. Gel permeation chromatography indicated that in contrast to literature reports, polymerization occurred in the organic phase and nanocapsules were obtained by interfacial precipitation of the polymer without any significant change of the molecular weight. Addition of SO2 to the organic phase before the introduction of the monomer allowed preparation of nanocapsules with a lower molecular weight. Nanospheres were prepared in a similar way albeit using an organic phase that was completely miscible within the aqueous phase so that solid spheres were obtained. Density gradient centrifugation revealed that nanocapsules had a density intermediate between nanospheres and an emulsion prepared in the same way without addition of monomer to the organic phase. Further, the process used to prepare nanocapsules had a high yield since no oil droplets or nanospheres were obtained by this process. Zeta potential of the nanocapsules and spheres was found to be related to the molecular weight of the polymer: values as high as approximately -42 mV were obtained for low molecular weight nanocapsules (MW approximately 1000) compared to approximately -10mV for the emulsion and the high molecular weight nanocapsules (MW approximately 100,000). Surface charge of the nanocapsules and molecular weight of their polymeric wall conditioned the adsorption capacity of poloxamers. Moreover, the highest adsorption was measured with the most hydrophobic poloxamer. These observations agree with previous work conducted on hydrophobic surfaces.
通过将单体加入有机相，随后将有机相与含有泊洛沙姆188、238或407的水相混合，制备了聚（异丁基氰基丙烯酸酯）和聚（异己基氰基丙烯酸酯）纳米胶囊。凝胶渗透色谱表明，与文献报道相反，聚合反应发生在有机相中，纳米胶囊是通过聚合物的界面沉淀获得的，分子量没有任何显著变化。在引入单体之前向有机相中添加SO2，可以制备分子量较低的纳米胶囊。纳米球的制备方法类似，只是使用了在水相中完全可混溶的有机相，从而得到了实心球。密度梯度离心显示，纳米胶囊的密度介于纳米球和以相同方式制备但未向有机相中添加单体的乳液之间。此外，用于制备纳米胶囊的过程产率很高，因为通过该过程没有获得油滴或纳米球。发现纳米胶囊和纳米球的ζ电位与聚合物的分子量有关：低分子量纳米胶囊（分子量约为1000）的ζ电位高达约-42 mV，而乳液和高分子量纳米胶囊（分子量约为100,000）的ζ电位约为-10 mV。纳米胶囊的表面电荷及其聚合物壁的分子量决定了泊洛沙姆的吸附能力。此外，用疏水性最强的泊洛沙姆测得的吸附量最高。这些观察结果与之前在疏水表面上进行的工作一致。
