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Nucleation kinetics of polymorphs: Induction period and interfacial energy measurements

机译：多晶型的成核动力学：诱导期和界面能测量

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Nucleation kinetics of eflucimibe polymorphs have been investigated in ethanol and n-heptane mixture. The two eflucimibe polymorphs, A and B, crystallize concomitantly for a wide range of operating conditions. The effects of supersaturation on the nucleation rates of the two existing polymorphs were analyzed. The relative nucleation rates of A and B form determine the nature of the polymorph obtained at the end of the crystallization process. The determination of the induction time for polymorphs allows to determine the crystal-solution interfacial energy for the two forms: gamma(sl)(A) = 5.17, gamma(sl)(B) = 4.23 mj m(-2). The values obtained were compared with the, ones obtained from direct methods: by contact angle measurement (7.32 mj m(-2)) and is significantly lower than values predicted by equations derived from simplified theories (15 mJ m(-2)). From induction time measurements, the nucleation rate of each polymorph was determined. The evolution of the nucleation rate with supersaturation allows the determination of the occurrence domain of each polymorph. It was found experimentally, at low (S < 1.8) and high supersaturation (S > 2.7), that the polymorphic powder composition is in agreement with the occurrence domains determined from nucleation rates. However, at intermediate supersaturation, due to the nearly equivalent structure of the two polymorphs, the occurrence domain of concomitant nucleation is wider than expected.
机译：已经在乙醇和正庚烷混合物中研究了依氟米贝多晶型的成核动力学。两种eflucimibe多晶型物A和B在广泛的操作条件下会同时结晶。分析了过饱和度对两种现有多晶型的成核速率的影响。 A和B形式的相对成核速率决定了在结晶过程结束时获得的多晶型物的性质。多晶型物的诱导时间的确定允许确定两种形式的晶体溶液界面能：γ（sl）（A）= 5.17，γ（sl）（B）= 4.23 mj m（-2）。将获得的值与通过直接方法获得的值进行比较：通过接触角测量（7.32 mj m（-2）），该值显着低于通过简化理论得出的方程式所预测的值（15 mJ m（-2））。从诱导时间测量，确定每种多晶型物的成核速率。随着过饱和成核速率的演变，可以确定每个多晶型物的出现域。通过实验发现，在低（S <1.8）和高过饱和度（S> 2.7）下，多晶型粉末组成与根据成核速率确定的出现域一致。但是，在中间过饱和时，由于两个多晶型物的结构几乎相同，因此伴随形核的出现域比预期的要宽。

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