紫草素微囊的固化机制与性能

目的考察单宁酸和氯化钙作为固化剂对微囊的成囊性及体外释药特征的影响,并对其固化机制进行探讨。方法以明胶和海藻酸钠为壁材,单宁酸和氯化钙作为固化剂,采用复凝聚法制备紫草素微囊;用扫描电子显微镜、激光粒径测试仪、红外光谱仪等手段研究微囊微球的形态结构;采用转篮法评价微囊的体外释药特性。结果制备得到了球形良好、缓释效果良好的单宁酸微囊,单宁酸和氯化钙制备的微囊包封率分别为90.34%±1.36%和69.89%±1.28%;平均粒径为241.7±6.94和278.1±4.74 nm,Zeta电位为-27.3±3.6和-24.7±3.2 mV;红外图谱显示单宁酸固化的微囊可以将紫草素包裹得更完全,使紫草素的特征峰完全消失,而氯化钙固化的微囊只能包裹部分紫草素,不能使其特征峰消失。体外释放实验结果表明,单宁酸作固化剂制备的微囊在12 h时释药率达到96.81%;而以氯化钙作固化剂制备的微囊,在6 h时释药率达到97.57%。结论固化剂的选择对微囊的成囊有较大的影响,为微囊固化剂的研究奠定了基础。

Curing mechanism and properties of Shikonin Microcapsules

Objective To investigated the effects of tannic acid and calcium chloride as curing agents on the capsulation and in vitro release characteristics of microcapsules and to discuss.The curing mechanism of curing agent.Methods With gelatin and sodium alginate as wall materials and tannic acid and calcium chloride as curing agents,comfrey microcapsules were prepared by complex condensation method.The morphology and structure of microcapsules and microspheres were studied by means of scanning electron microscope,laser particle size tester and infrared spectrometer.The in vitro drug release characteristics of microcapsules were evaluated by basket rotation.Results Microcapsules of tannic acid with good spherical shape and good slow-release effect were prepared.The encapsulation rates of tannic acid and calcium chloride were 90.34%±1.36%and 69.89%±1.28%,respectively.The average particle sizes were 241.7±6.94,278.1±4.74 nm,and the Zeta potentials were-27.3±3.6,-24.7±3.2 mV,respectively.Infrared spectrum showed that tannic acid-cured microcapsules could completely encapsulate shikonin and eliminate the characteristic peaks of shikonin,while calcium chloride cured microcapsules could only partially encapsulate shikonin but could not eliminate its characteristic peaks.In vitro release experiments showed that the drug release rate of microcapsules prepared with tannic acid as curing agent reached to 96.81%at 12 h,and that of microcapsules prepared with calcium chloride as curing agent reached to 97.57%at 6 h.Conclusion The choice of curing agent has a great influence on the cystic formation of microcapsules,which provides basis for the study of curing agent for microcapsules.