单宁酸缓释微球的制备工艺优化及其体外释放研究

Optimization of preparation process for tannic acid sustained-release microspheres and their in vitro release

以包封率和载药量为指标,采用单因素实验及正交设计试验对单宁酸微球的制备工艺进行优化,利用扫描电镜(SEM)、傅里叶变换红外光谱(FT-IR)对其结构进行表征分析,并对单宁酸微球在模拟胃液和肠液中的体外释放规律进行了研究。结果表明:制备的微球形状规则,形成了空囊结构。单宁酸微球的最佳制备工艺条件为海藻酸钠与药物(单宁酸)比为1.5∶1、环糊精质量的分数为0.2%、海藻酸酸钠的质量分数2%以及氯化钙的质量分数为0.5%,在此条件下包封率和载药量分别达到95.17%和43.95%。单宁酸微球在人工胃液(pH=1.70)和人工肠液(pH=6.86)中释放24h的累计释放率分别为25.06%、74.26%。微球在模拟胃液中的释放符合Higuchi模型,在肠液中的释放符合一级动力学模型。

The preparation process of tannic acid microspheres was optimized by using one-way test and orthogonal design test with encapsulation rate and drug loading capacity as the indexes.The structure was characterized and analyzed using scanning electron microscopy(SEM)and Fourier transform infrared spectroscopy(FT-IR),and the in vitro release law of tannic acid microspheres in simulated gastric and intestinal fluids was studied.The results showed that the prepared microspheres were regular in shape and formed an empty capsule structure.The optimal process conditions for the preparation of tannic acid microspheres were a sodium alginate to drug(tannic acid)ratio of 1.5∶1,a fraction of cyclodextrin by mass of 0.2%,a mass fraction of sodium alginate by mass of 2%,and a mass fraction of calcium chloride by mass of 0.5%.Under these conditions,the encapsulation and drug loading rates reached 95.17%and 43.95%,respectively.The cumulative release rates of tannic acid microspheres in artificial gastric fluid(pH=1.70)and artificial intestinal fluid(pH=6.86)released for 24h were 25.06%and 74.26%,respectively.The release of microspheres in simulated gastric fluid followed the Higuchi model,while the release in intestinal fluid followed the first-order kinetic model.