尼群地平晶型转变条件及其影响因素的确定

根据熔化数据推算相变稳定性理论计算了尼群地平不同晶型之间的相变温度, 并分别考察了高温、高温和高湿及高压条件下的晶型转变. 理论推导尼群地平I与II, 尼群地平I与III, 尼群地平II与III的转化温度分别为158.88, 160.50和158.65 ℃, 三者均为单变关系, 且在高温条件下尼群地平II, III都转变为尼群地平I, 在高压条件下, II易转变为I. 试验结果表明室温下尼群地平I为稳定型, II和III为亚稳定型, 3种晶型稳定性顺序为尼群地平I＞II＞III.

Conversion Conditions and Influence Factors of Nitrendipine Crystal Polymorphism

Theoretical conversion temperature was calculated between different crystal forms of nitrendipine from melting data. The different conversion conditions were investigated, such as high temperature, high temperature and humidity and high pressure. The theoretical conversion temperature between nitrendipine I and II is 158.88 ℃, that between nitrendipine I and III is 160.50 ℃ and that between nitrendipine II and III is 158.65 ℃, indicating nitrendipine polymorphs belong to a monotropic system. At high temperature, nitrendipine II and III both converted to I. Under high pressure, II converted to I. The results indicate that nitrendipine I was a stable form, while II and III were metastable form. The stability ranked as I＞II＞III.