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首页> 外文学位 >Homogeneous nucleation induction time measurement and prediction of solubility and the relative stability of polymorphs.
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Homogeneous nucleation induction time measurement and prediction of solubility and the relative stability of polymorphs.

机译：均相成核诱导时间的测量以及对多晶型物的溶解度和相对稳定性的预测。

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摘要

The purpose of this work is to investigate the nucleation behavior of glycine through measurements of nucleation induction time and to evaluate methods for the prediction of solubility of organic compounds as well as to determine if the computational methods employed can determine the stability of enantiotropic polymorphs and their transition temperature.;An electrodynamic levitation trap (ELT) was used to suspend a small charged droplet (25-50mum) without a container using an electric filed. This novel technique enables the measurement of the homogeneous nucleation induction time at high levels of supersaturation at almost identical conditions. The induction time data measured were fitted to Turnbull's model and an empirical model related to two-step nucleation. The nucleation rates of glycine from aqueous solution were calculated using these models. The results obtained showed that glycine does not fit the classical model of Turnbull and is fit well by the empirical model. While ammonium sulfate (an ionic material) is previous work was shown to fit Turnbull's model.;A Conductor-like screening model for real solvents (COSMO-RS), which is based on quantum chemical calculations and a statistical thermodynamic method, was used to calculate solubility and to determine the stability of polymorphs of drug compounds. The solubility results indicate that the COSMO-RS method is not superior to conventional group contribution methods. In addition, solubility calculations using molecules of interest did not correctly predict the solubility relationship between enantiotropic polymorphs. However, calculations using the unit cell of the compound showed some possibility of using this method for prediction of the relative stability of polymorphs.
机译：这项工作的目的是通过测量成核诱导时间来研究甘氨酸的成核行为，并评估预测有机化合物溶解度的方法，并确定所用的计算方法是否可以确定对映多晶型及其稳定性。电动悬浮捕集器（ELT）用于在没有容器的情况下使用电场悬浮小的带电液滴（25-50mum）。这项新技术可以在几乎相同的条件下，在高过饱和水平下测量均相成核诱导时间。测得的感应时间数据符合Turnbull模型和与两步成核有关的经验模型。使用这些模型计算了水溶液中甘氨酸的成核率。所得结果表明，甘氨酸不符合Turnbull的经典模型，而与经验模型非常吻合。以前的工作是硫酸铵（一种离子材料）被证明适合Turnbull模型。;基于量子化学计算和统计热力学方法的真实溶剂类似导体的筛选模型（COSMO-RS）用于计算溶解度并确定药物化合物多晶型物的稳定性。溶解度结果表明，COSMO-RS方法并不优于常规的基团贡献方法。此外，使用目标分子的溶解度计算不能正确预测对映多晶型物之间的溶解度关系。但是，使用化合物的晶胞进行计算表明，使用该方法预测多晶型物的相对稳定性存在一定的可能性。

著录项

  • 作者

    Lee, Ho Yeon.;

  • 作者单位

    Illinois Institute of Technology.;

  • 授予单位 Illinois Institute of Technology.;
  • 学科 Engineering Chemical.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 110 p.
  • 总页数 110
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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