阿奇霉素一水晶型与二水晶型的制备与转化

Preparation and Transformation of Azithromycin in the forms of Monohydrate and Dihydrate

阿奇霉素存在2种不同的晶型：一水晶型和二水晶型，可通过控制结晶过程中的条件来制备。阿奇霉素二水晶型比一水晶型更稳定，一水晶型在一定的条件下转化为二水晶型。一水晶型是动力学控制的稳定状态，而二水晶型是热力学控制的稳定状态。制备方法的区别以20g阿奇霉素粗品、50mL丙酮投料量为例，一水晶型制备初次加水5mL，养晶温度54～56℃，养晶0．5h；二水晶型制备初次加水10mL。养晶温度38～42℃，养晶2h。

Azithromycin is a macrolide antibiotic with two crystalline forms of monohydrate and dihydrate. They can be prepared by changing the crystallization conditions. The dynamically stable monohydrate can be converted to the thermodynamically stable dihydrate in crystallization process. For example, 20 g of azithromycin was dissolved in 50 mL of acetone. The monohydrate was prepared under conditions that the first amount of water was 5 mL, the temperature and the time of crystal growing was 54-56℃ and 0.5 h. The dihydrate was prepared under conditions that the first amount of water was 10 mL, the temperature and the time of crystal growing was 38- 42℃ and 2 h.