Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, O-okayama, Meguro, Japan.
Int J Pharm. 2009 Oct 20;381(1):34-9. doi: 10.1016/j.ijpharm.2009.07.021. Epub 2009 Jul 29.
Mg-Al-ascorbic acid (ASA)-layered double hydroxides (ASA-LDHs) with Mg/Al=3 were synthesized by ion-exchange, coprecipitation and reconstruction methods. Composites with sodium oleate (SOA)/ASA-LDH were prepared by an ion-exchange method using various concentrations of SOA solutions. The (003) basal spacing of the ASA-LDHs changed from 0.76nm in the CO(3)-LDH to 0.78 and 0.86nm after intercalation of the ASA ions and these basal spacings are in good agreement with models based on the assumption as mono layers and double layers of ASA ions in the LDH interlayers, respectively. The amounts of ASA in the LDHs prepared by the reconstruction method were higher than those by the ion-exchange and coprecipitation methods. In the preparation of composites of SOA/ASA-LDH, an ion-exchange method was more suitable than a reconstruction method to cause surface sorption of the SOA molecules with maintaining intercalated ASA ions in the LDH interlayers. The acid-resistant properties of the composites of SOA/ASA-LDH were found to be much higher than for the pure ASA-LDH and mixture of CO(3)-LDH and ASA. The surfaces of the LDH particles in the composites are, thus, mostly covered with sorbed SOA molecules and they are good candidates as drug delivery materials for intestines through the stomach.
采用离子交换、共沉淀和重构方法合成了 Mg/Al=3 的 Mg-Al-抗坏血酸（ASA）-层状双氢氧化物（ASA-LDH）。通过离子交换方法，使用不同浓度的油酸钠（SOA）溶液制备了含有 SOA/ASA-LDH 的复合材料。ASA 离子插层后，ASA-LDH 的（003）基面间距从 CO3-LDH 的 0.76nm 分别变为 0.78nm 和 0.86nm，这些基面间距与基于假设的模型一致，分别为 LDH 层间的单和双层 ASA 离子。与离子交换和共沉淀方法相比，重构方法制备的 LDH 中 ASA 的量更高。在 SOA/ASA-LDH 复合材料的制备中，离子交换方法比重构方法更适合于表面吸附 SOA 分子，同时保持 LDH 层间插层的 ASA 离子。SOA/ASA-LDH 复合材料的耐酸性明显高于纯 ASA-LDH 和 CO3-LDH 与 ASA 的混合物。因此，复合材料中 LDH 颗粒的表面大部分被吸附的 SOA 分子覆盖，它们是通过胃进入肠道作为药物输送材料的良好候选物。
