中文摘要：

以镁铁尖晶石（MgFe2O4）颗粒为磁性基质，采用共沉淀法制备了替加氟（TF）插层层状双金属氢氧化物（LDHs）包覆MgFe2O4的核-壳结构磁性纳米复合体[MgFe2O4@（TF-LDHs）]，并对其化学组成、晶体结构和磁性等进行了表征，探讨了TF在LDHs层间的存在状态，考察了TF的释放行为．实验结果表明，MgFe2O4@（TF-LDHs）纳米复合体具有顺磁性，其比饱和磁化强度随磁性基质含量的增大而增强；TF分子在LDHs层间以长轴略倾斜于LDHs层板的方式呈双层排布；MgFe2O4@（TF—LDHs）纳米复合体具有明显的药物缓释效果，其释放动力学过程符合准二级动力学方程，释放机理为Fick扩散；增大磁性基质含量或施加外加磁场均可减缓其药物释放过程．

英文摘要：

Using magnesium ferrite （ MgFe2O4 ） as nanocomposites possessing a core-shell structure wi magnetic substrates, a series of MgFe2O4 @ （TF-LDHs） th a tegafur（TF） intercalated Zn-Al layered double hydro- xides （LDHs） shell coated onto the surface of magnetic MgFe2O4 core was assembled via a one step coprecipitation method. The chemical composition, crystal structure, magnetic property, arrangements of tegafur within interlayer and drug release behavior of the magnetic nanocomposite were investigated systematically. The resuits show that MgFe2O4@ （TF-LDHs） nanocomposites have a paramagnetism and the saturation magnetization are enhanced with increasing the magnetic substrates content. Tegafur molecules are arranged as a bilayer with the long axis slightly tilting to the LDHs layers. The release kinetics of tegafur from MgFe2O4@ （TF-LDHs） nanocomposites was investigated in pH = 7.2 and pH = 4.8 buffer solutions. It was found that the release process might fit the pseudo-second-order release kinetics and the release mechanism was Fick diffusion. The in vitro drug release from the nanocomposites is remarkably lower than that from the corresponding physical mixture and the release rate reduce gradually with increasing the content of magnetic substrate or under an external magnetic field, showing that the MgFe2O4 @ （drug-LDHs） is a potential magnetic targeting drug delivery-controlled-release system.