黄芩苷结肠定位固体分散体的制备及其体外释放度评价

目的： 拟制备pH依赖型黄芩苷结肠定位固体分散体，以期达到结肠定位和快速释药的目的。方法： 采用溶剂法制备黄芩苷-Eudragit S100固体分散体，运用差示扫描量热法（DSC）、扫描电镜法（SEM）、X-射线粉末衍射法（XRD） 、红外光谱（IR）等分析方法对其微观结构和理化性质进行了分析，并对其体外释放性能进行考察。结果： DSC和XRD分析结果显示黄芩苷以非晶体形式分散在固体分散体中，IR结果表明黄芩苷与Eudragit S100之间可能存在非共价键作用。体外释放度测定结果表明，黄芩苷-Eudragit S100比例达到1：6时，药物在pH 1.2的稀盐酸溶液2 h中基本不释放；在pH 6.8的磷酸缓冲液中，4 h累积溶出率小于15%；在pH 7.6的磷酸缓冲液中，1 h累积溶出度达到90%以上。结论： 所制备的黄芩苷-Eudragit S100固体分散体能够达到结肠定位和快速释药的目的，并提高结肠部位黄芩苷的浓度。

Preparation of baicalin colon-specific solid dispersion and evaluation on its in vitro release

Objective: To prepare pH-dependent baicalin colon-specific solid dispersion, with the aim of colon-specific delivery and rapid drug release. Method: Baicalin-eudragit S100 solid dispersion was prepared by using the solvent method. The microscopic structure and physicochemical properties were analyzed by using differential scanning calorimetry (DSC), scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and infrared spectroscopy (IR). And its in vitro release was also investigated. Result: The results of DSC and XRD analysis suggested that baicalin may be dispersed in solid dispersion in the amorphous state. IR results indicated a non-covalent bond effect may exist between baicalin and eudragit S100. The results of in vitro release determination showed that very few baicalins in pH 1.2 diluted hydrochloric acid solution for 2 h at the baicalin-eudragit S100 ratio of 1:6. The accumulated dissolution rate was less than 15% in pH 6.8 phosphate buffer solution for 4 h, but exceeding 90% in pH 7.6 phosphate buffer solution for 1 h. Conclusion: The prepared baicalin-eudragit S100 solid dispersion could achieve the objective of colon-specific delivery and rapid drug release, and helps increase the concentration of baicalin in colons.