不同晶型倍他米松醋酸酯形成机理研究

目的：研究不同晶型倍他米松醋酸酯制备，分析其形成机理。方法：采用溶剂重结晶，研磨，溶剂转换等方法制备，应用红外光谱、粉末X射线衍射和热分析等技术加以鉴定。结果：制备了倍他米松醋酸酯的三种晶型和一个水化物，确定了它们的熔点，粉末X射线衍射特征及红外光谱特征。结论：倍他米松醋酸酯产生多晶型的原因是由于分子结构中活泼的羟基，在制备中产生的无定形和较低的温度是倍他米松醋酸酯水化物形成的重要条件。

Study on Mechanism of Formation of Betamethasone Acetate Different Crystal Forms

AIM: The purpose is to prepare different crystal forms of betamethasone acetate,and to analyse the mechanism of formation. METHOD: Different crystal forms were prepared by recrystallization from solvents, grinding, changing solvents. And the crystall structure were analyzed by means of the following techniques were used: DSC,TG, X -ray powder diffraction and IR spectroscopy. RESULT: The characteristic parameters of polymorphs and hydrate of betamethasone acetate were identified. CONCLUSION: The polymorphic phenomenon of betamethasone acetate is due to active OH of molecule; amorphous from and low temperature is helpful to the formation of hydrate.