黄芩苷的处方前研究

Preformulation Study on Baicalin

目的通过处方前研究,阐明黄芩苷原料药(质量分数为85.5%)的基本理化性质。方法采用HPLC法测定黄芩苷含量,分别进行黄芩苷的平衡溶解度、油水分配系数、破坏性试验、吸湿性考察等处方前研究。结果原料药中黄芩苷在水中的平衡溶解度为0.0326 mg/m L,较甲醇、正丁醇、乙醇等溶剂低;在p H小于5.0的磷酸盐缓冲液中几乎不溶,其平衡溶解度随着p H值的增大呈增大的趋势;黄芩苷在正辛醇/水中的油水分配系数(P值)为1.19,在正辛醇/磷酸盐缓冲液(p H 2~10)中的P值均比正辛醇/水中的低;黄芩苷不耐碱,且易被氧化;在温度25℃、RH 75%条件下吸湿性较小。结论该研究可为黄芩苷新制剂原料与剂型的选择、处方设计及工艺优化等提供实验依据。

Objective To illustrate the basic physiochemical characteristic of active pharmaceutical ingredient baicalin(mass fraction 85.5%) by preformulation study. Methods The content of baicalin was determined by HPLC. The equilibrium solubility, oilwater partition coefficient and destructive testing on baicalin of preformulation was studied. Results The equilibrium solubility of baicalin in water was 0.032 6 mg/m L. It was almost insoluble in the phosphate buffer solutions with p H value under 5.0, but its solubility increased with the increasing of p H. The oil-water partition coefficient(P) of baicalin in n-octyl alcohol/water was1.19, higher than in n-octyl alcohol/ phosphate buffer solutions with p H values of 2~10. Baicalin was not alkali-resistant and easy to be oxidized. The hygroscopicity of baicalin is lesser under the condition of 25℃ and RH75%. Conclusion The above results can provide experimental basis for selection of active pharmaceutical ingredients and dosage forms, prescription design and process optimization of new baicalin preparation.