大黄素/Mg-Zn-Al-LDHs纳米杂化物的制备及缓释性能研究

Synthesis and release behavior of emodin intercalated into Mg-Zn-Al layered double hydroxide

为克服大黄素循环周期短、毒副作用大等缺点,本研究以Mg-Zn-Al型层状双金属氢氧化物(Mg-Zn-Al-LDHs)为前驱体,采用二次组装法将大黄素分子成功插入到Mg-Zn-Al-LDHs层间,并探讨了反应温度和原料配比等因素对该纳米杂化物载药量的影响。XRD结果显示,随样品载药量增加,Mg-Zn-Al-LDHs粒子层间距由0.48 nm增大到3.42 nm。分别在pH4.8和pH7.5的缓冲溶液中测定了大黄素/LDHs的缓释性能,结果表明大黄素/LDHs的药品释放速率明显低于二者的物理混合物中的药品释放速率。本研究还探讨了大黄素/LDHs的释放机理,实验数据表明:在pH7.5时,大黄素的释放行为受扩散过程控制;在pH4.8时,层间药物主要通过载体的溶解释放出来。

The drug emodin was first intercalated into the layers of Mg-Zn-Al layered double hydroxides（Mg-Zn-Al-LDHs） by the re-assemble method.The emodin/LDHs nanohybrids could be used to extend the action duration and reduce the side effect of emodin.Then the effect of the temperature T and the mass ratio R of emodin to LDHs on drug loading were discussed.The XRD spectra indicated that the interlayer distance of Mg-Zn-Al-LDHs increased from 0.48 nm to 3.42 nm with the increase of drug loading.The determination results of the drug release showed that the drug release rate from the emodin/LDHs nanohybrids was much slower than that of the corresponding physical mixture with the pH of solution of either 4.8 or 7.5.Analysis showed that the mechanism of the pH 7.5 release was primarily through ion-exchange with the ions in the buffer solution,while that of the pH4.8 release was primarily through the dissolution of LDHs.