【作者】 张少杰；

【导师】 侯万国；

【作者基本信息】 青岛科技大学 ， 无机化学， 2010， 硕士

【摘要】 层状双金属氢氧化物(也称为类水滑石,layered double hydroxides,简称LDHs)是由两种或两种以上金属元素组成的具有水滑石层状晶体结构的氢氧化物,层片带结构正电荷,层间存在可交换的阴离子。由于LDHs的特殊层状结构,可以把药物分子插层到LDHs层间,形成药物-LDHs纳米杂化物。药物与层板间通过静电作用、氢键等化学作用力以及空间位阻效应等使药物稳定存在于层间,一定条件下可实现药物的有效控释。因此药物-LDHs纳米杂化物被认为是一类极具应用前景的药物载体和缓/控释材料。本文选用能溶于水的非离子型抗癌药物替加氟(Tegafur),难溶于水的农药哒螨灵(Pyridaben)作为插层客体分子,分别采用共沉淀法和结构重建法合成药物-LDHs纳米杂化物,运用XRD、FT-IR等测试手段对所得产物进行了表征,并考察了纳米杂化物在一定条件下的释放性能。研究的主要内容和结论归纳如下:1、LDHs的制备及表征合成了不同金属元素配比的MgAl-Cl LDHs,ZnAl-NO3 LDHs,考察了原料配比对产物中金属摩尔比及不同的金属盐对层间距的影响。结果表明制备的MgAl-Cl LDHs样品中Mg的含量均比原料中的低,ZnAl-NO3 LDHs亦有相同结果。MgAl-Cl LDHs层间距在0.78 nm左右,ZnAl-NO3 LDHs层间距约为0.86 nm。2、Tegafur-LDHs纳米杂化物的制备与表征首先采用共沉淀法制备了Tegafur-ZnAl-LDHs纳米杂化物,采用结构重建法制备Tegafur-MgAl-LDHs纳米杂化物,研究了不同的药物初始浓度对杂化物载药量(Ain)的影响,表明药物初始浓度越大,杂化物的载药量越大。然后模拟人体内条件,研究了37℃下,pH值分别为4.8和7.2的缓冲溶液中药物的释放行为,结果表明该杂化物中的药物具有良好的缓释性能,其释放过程符合准二级动力学方程。在pH 7.2的中性介质中的释放速率明显低于在pH 4.8的酸性介质中的释放速率,而在超纯水中的释放速率又明显的低于在缓冲溶液中的释放速率,表明其释放机理有所差别。Tegafur-LDHs杂化物的缓释效果说明LDHs可以作为药物缓释的纳米载体。3、Pyridaben-LDHs纳米杂化物的制备与表征采用共沉淀法制备了Pyridaben-LDHs纳米杂化物,考察了不同的药物初始浓度对杂化物载药量的影响,研究结果表明随着药物初始浓度的越大,杂化物的载药量越大。此外,还研究了杂化物在乙醇-水溶液(体积比Rv=4/1)中缓释效果,研究表明,恒温15℃下杂化物中哒螨灵的释放符合准二级动力学方程,具有明显的缓释作用。因此,Pyridaben-LDHs纳米杂化物具有作为农药控释体系的发展潜力。更多还原

【Abstract】 Layered double hydroxides (LDHs) are consisting of divalent and trivalent metal ions and with the same layered crystal structure as Hydrotalcite, they are a family of layered solids with structurally positively charged layers and interlayer balancing anions which can be replaced by the desired anions. Some drug molecules can be intercalated into the gallery of LDHs to form drug-LDHs nanohybrids because of their special structure. The drugs can be evidently stabilized in the interlayer of such nanohybrids because of the electrostatic, hydrogen bond, and steric hindrance in the gallery, and thus they have controlled-release characters under certain condition. Therefore, drug-LDHs nanohybrid material was considered as a potential drug carrier for controlled release.In this paper, Tegafur and Pyridaben were selected as the guest molecules and their drug-LDHs nanohybrids were synthesized via coprecipitation or reconstruction. Powder X-ray diffraction (PXRD) and FT-IR spectroscopy were used to characterize the achieved products, and the drug releases and kinetics from nanohybrids were investigated as well.1. Synthesis and characterisation of LDHsThe pristine MgAl-Cl LDHs and ZnAl-NO3 LDHs were prepared by coprecipitation method. The effects of the molar ratio of M3+/ [M2+ + M3+] molar ratio show that M3+/ M2+ molar ratio of the syntheized product was lower than that of the raw mixed salt solution. The interlayer space is about 0.78 nm for MgAl-Cl LDHs, 0.86 nm for ZnAl-NO3 LDHs. Moreover, a simple environmentally friendly method was used to prepare the ZnAl-NO3 LDHs, in which ammonia was not needed in the coprecipitation, as well as the washing or purification of the final product.2. Tegafur-LDHs nanohybridsTegafur-ZnAl-LDHs were prepared by coprecipitation method, while Tegafur-MgAl-LDHs were syntesized by reconstruction. The loading amount of Tegafur on LDHs was dependent on the Tegafur initial concentration, i.e. the loading amount increased with the initial concentration. The release results of Tegafur from the nanohybrid at pH 7.2 and pH 4.8 in buffer solution at 37℃suggest that the Tegafur-LDHs have a good controlled-release character. The drug release kinetics from the nanohybrids showed the pseudo-second order kinetic model. The release rate at pH 7.2 is remarkably lower than that at pH 4.8, and that in pure water is lower than that in the buffer solution, which can be ascribed to a possible difference in the release mechanism. 3. Pyridaben-LDHs nanohybridsPyridaben-MgAl-LDHs were prepared by coprecipitation method. The loading amount of Pyridaben on LDHs was dependent on the Tegafur initial concentration, similar to that of Tegafur-ZnAl-LDHs. The releases of Pyridaben from the Pyridaben-MgAl-LDHs nanohybrids in ethanol-water solution at 15℃indicate that the Pyridaben-LDHs nanohybrids have potential for development of new controlled-release formulations of pesticides.更多还原