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目的研究岩白菜素的理化性质。方法通过X-射线粉末衍射(powder X-ray diffraction patterns,PXRD),差示扫描量热分析(differential scanning calorimetry,DSC),热重量分析法(thermogravimetric analysis,TGA),吸湿性实验以及湿、热稳定性实验研究岩白菜素的固态理化性质;在不同pH、不同温度条件下研究岩白菜素的溶解度;采用非水滴定法测定解离常数pKa;采用正辛醇-水系统测定岩白菜素的表观油/水分配系数。结果PXRD研究结果表明,岩白菜素在溶解过程以及潮湿环境下均未发生晶型转变;DSC,TGA研究结果表明,岩白菜素为一水合物;在湿热条件下该药能稳定存在;其水中溶解度较低,解离常数为pKa1(5.46±0.13)和pKa2(5.74±0.18),为极弱酸;表观油/水分配系数具有pH依赖性,但亲脂性较差。结论本实验确定了岩白菜素的主要理化性质,有利于其生物药剂学的研究以及新剂型的开发。
Objective To study the physicochemical properties of Bergenin. The method was characterized by powder X-ray diffraction patterns (PXRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), hygroscopicity experiments, and wet and hot The stability experiment was carried out to study the physicochemical properties of bergenin. The solubility of bergenin was studied under different pH and different temperature. The dissociation constant pKa was determined by non-aqueous titration. The content of bergenin was determined by n-octanol-water system View oil / water partition coefficient. Results The results of PXRD showed that there was no crystal transition of bergenin during the dissolution and the humid environment. The results of DSC and TGA indicated that bergenin was monohydrate, which was stable under the conditions of hot and humid. Solubility was low and the dissociation constants were pKa1 (5.46 ± 0.13) and pKa2 (5.74 ± 0.18), which were very weak acids. Apparent oil / water partition coefficients were pH-dependent but poorly lipophilic. Conclusion The main physical and chemical properties of bergenin were identified in this experiment, which is conducive to the research of biopharmaceuticals and the development of new dosage forms.