Thermal decomposition kinetics and solution thermodynamics of two polymorphs, felodipine form I and form IV, were investigated. The thermal decomposition kinetics of the polymorphs, containing thermal decomposing mechanism and the kinetic parameters were studied under non-isothermal conditions using Popescu method, and the shelf life was simply calculated. The results showed that nucleation and growth (n = 3/4) of Avremi–Erofeev equation is the most probable mechanism function for form I, and the integral form is G(α) = [−ln(1 − α)]^3/4; while the Mample Powel law (n = 1) is the most probable mechanism function for form IV, corresponding to G(α) = α. Notably, the individual amorphous phases of crystal felodipine form I and IV were obtained after the heating–cooling cycle of DSC tests, which were identified by TMDSC and FT-IR measurements. As the interim products before the collapse, it can be inferred that different amorphous intermediates may be the determinant for different thermal decomposition mechanisms of crystal forms I and IV. The solubility data and solution thermodynamic parameters, including enthalpy, entropy and Gibbs free energy have also been calculated by Van’t Hoff equation in ethanol aqueous. The results illustrated the polymorphic pair is enantiotropic with the transition temperature of 322.23 K and the conversion is driven by entropy.

研究了两种多晶型物，非洛地平I型和IV型的热分解动力学和溶液热力学。利用Popescu方法研究了非等温条件下多晶型物的热分解动力学，包括热分解机理和动力学参数，并简单地计算了货架期。结果表明， Avremi-Erofeev方程的成核和生长（n = 3/4）是形式I的最可能的机理函数，并且积分形式为G（α）= [-ln（1-  α）] ^{3 / 4}；而范普威尔定律（n  = 1）是形式IV的最可能的机理函数，对应于G（α）=  α。值得注意的是，在DSC测试的加热-冷却循环后，获得了I型和IV型非洛地平晶体的单个无定形相，并通过TMDSC和FT-IR测量对其进行了鉴定。作为坍塌之前的中间产物，可以推断出，不同的无定形中间体可能是晶型I和IV不同热分解机理的决定因素。还通过Van't Hoff方程计算了乙醇水溶液中的溶解度数据和溶液热力学参数，包括焓，熵和吉布斯自由能。结果表明，该多晶型对是对映体，其转变温度为322.23 K，并且转化是由熵驱动的。