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首页> 外文期刊>Journal of Pharmaceutics >Influence of Air Temperature and Humidity on Dehydration Equilibria and Kinetics of Theophylline
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Influence of Air Temperature and Humidity on Dehydration Equilibria and Kinetics of Theophylline

机译：气温和湿度对茶碱脱水平衡和动力学的影响

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The effect of hygrothermal conditions (air temperature and relative humidity) on the dehydration of theophylline monohydrate was investigated. Firstly, the equilibrium states of theophylline were investigated. The data from gravimetric analysis at constant temperature and humidity were reported as desorption isotherms. The PXRD analysis was used to identify the different polymorphic forms of theophylline: the monohydrate, the metastable anhydrate, and the stable anhydrate. Solid-solid phase diagrams for two processing times were proposed. Secondly, the dehydration kinetics were studied. The water content evolutions with time were recorded at several temperatures from 20°C to 80°C and several relative humidities from 4% to 50%. Different mathematical models were used to fit the experimental data. The spatially averaged solution of 2D Fickian transient diffusion equation best represented the water mass loss versus time experimental relationship. The dehydration rate constant was found to increase exponentially with air temperature and to decrease exponentially with air relative humidity.
机译：研究了湿热条件（气温和相对湿度）对茶碱一水合物脱水的影响。首先，研究了茶碱的平衡状态。将在恒定温度和湿度下的重量分析数据记录为解吸等温线。 PXRD分析用于鉴定茶碱的不同多晶型形式：一水合物，亚稳态无水物和稳定无水物。提出了两个处理时间的固-固相图。其次，研究了脱水动力学。在20°C至80°C的几个温度和4％至50％的几个相对湿度下记录了水含量随时间的变化。使用不同的数学模型来拟合实验数据。二维Fickian瞬态扩散方程的空间平均解最能代表水量损失与时间的实验关系。发现脱水速率常数随空气温度呈指数增加，随空气相对湿度呈指数下降。

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