Richards A C, Harness J B, McColm I J
Department of Chemical Engineering, University of Bradford, Bradford, BD7 1DP, United Kingdom.
J Pharm Sci. 2000 Sep;89(9):1187-95. doi: 10.1002/1520-6017(200009)89:9<1187::aid-jps11>3.0.co;2-m.
A six-stage model is proposed to describe the overall process of sorption of water vapor on and into anhydrous nedocromil sodium. The way in which temperature, pressure, and time affect the rate of reaction for each of the stages has been analyzed. Experimental data for the measured rates, where temperature, pressure, and time are variables, are compared with the predictions obtained from each of the six stages. The most useful comparator is a graphical representation of reduced time versus hydration rate. The theoretical equations presented as a shape analysis of the experimental curves show the process to have different controlling mechanisms in three temperature regions: up to 27 degrees C, hydration is controlled by a nucleation and growth mechanism; between 27 and 31 degrees C, the process is dominated by diffusion of water molecules into the crystal; and >31 degrees C, neither nucleation nor diffusion are controlling but some, as yet, undetermined physical processes.
提出了一个六阶段模型来描述无水奈多罗米钠对水蒸气的吸附及吸收的整个过程。分析了温度、压力和时间对每个阶段反应速率的影响方式。将温度、压力和时间作为变量的测量速率的实验数据与六个阶段各自得到的预测结果进行了比较。最有用的比较方法是将折合时间与水合速率以图形表示。作为实验曲线形状分析给出的理论方程表明，该过程在三个温度区域具有不同的控制机制：高达27℃时，水合作用由成核和生长机制控制；在27至31℃之间，该过程由水分子向晶体中的扩散主导；高于31℃时，成核和扩散均不起控制作用，而是一些尚未确定的物理过程。
