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采用共沉淀法和离子交换法实现了谷氨酸与Zn/Al水滑石的插层组装,并采用X射线粉末衍射、差热分析、红外光谱表征了谷氨酸插层水滑石的结构,并在模拟胃液和肠液中测试了复合材料中谷氨酸的缓释性能。结果表明,合成的水滑石前躯体(LDHs-NO3)结构规整、晶相单一,层间距为0.879 nm;2种方法合成的谷氨酸插层水滑石,其层间距分别增加到1.251 nm和1.334 nm,可以推测谷氨酸以垂直方式分布于水滑石层间。插层后水滑石样品在1588 cm-1和1346 cm-1处出现了谷氨酸中羧酸根的不对称伸缩振动和对称伸缩振动峰,也佐证了氨基酸插层成功。谷氨酸插层水滑石后,其热稳定性大大提高,热分解温度由230℃升高至397～434℃。与物理混合法相比,谷氨酸与水滑石复合后增加了谷氨酸的耐酸性,使其具有较好的缓释性能。谷氨酸释放曲线符合Bhaskar方程,表明微粒间的扩散作用是谷氨酸分子释放的限速步骤。LDHs-Glu经海藻酸钠包裹后,在模拟肠液中缓慢释放而在模拟胃液中不释放,起到了肠液定向释放的效果。
The intercalation and assembly of glutamic acid and Zn / Al hydrotalcite were achieved by coprecipitation and ion exchange. The structure of glutamate intercalated hydrotalcite was characterized by X-ray powder diffraction, differential thermal analysis and infrared spectroscopy The release properties of glutamic acid in the composite were tested in simulated gastric fluid and intestinal fluid. The results show that the synthesized hydrotalcite precursors (LDHs-NO3) have a regular structure with a single crystal phase and a layer spacing of 0.879 nm. The interlayer spacing of glutamate-intercalated hydrotalcite synthesized by the two methods increases to 1.251 nm and 1.334 nm, it is presumed that glutamic acid is distributed vertically between the hydrotalcite layers. The intercalated hydrotalcite samples showed asymmetric stretching vibration and symmetrical stretching vibrational peaks of carboxylate at 1588 cm-1 and 1346 cm-1, which also proved the successful intercalation of amino acids. After glutamic acid intercalated hydrotalcite, its thermal stability is greatly improved, the thermal decomposition temperature increased from 230 ℃ to 397 ~ 434 ℃. Compared with the physical mixing method, the combination of glutamic acid and hydrotalcite increased the acid resistance of glutamic acid and made it have better sustained-release properties. The glutamate release curve is in accordance with the Bhaskar equation, indicating that the interparticle diffusion is the rate-limiting step in glutamate release. After LDHs-Glu was wrapped in sodium alginate, it was slowly released in the simulated intestinal fluid and not released in the simulated gastric fluid, which resulted in the directional release of intestinal fluid.