Schoonen A J, de Vries-Nijboer G W, Huizinga T
J Pharm Sci. 1979 Feb;68(2):163-8. doi: 10.1002/jps.2600680211.
A model system was developed in which the dissolution behavior of a single crystal of potassium ferricyanide was studied at a liquid paraffin-water interface. Since the equilibrium position of a crystal at the interface is independent of its size, the lifetime of a crystal dissolving at the interface is determined entirely by its initial size and its dissolution rate in the water phase. The dimensions of every crystal were measured microscopically before dissolution. A continuous-flow recording dissolution apparatus was used to measure spectrophotometrically the mass flow of dissolved potassium ferricyanide. The dissolution cell in this system was mounted in an optical bench, making it possible to follow dissolving crystals visually by projecting them on a screen. The results show that the lifetime of a crystal is proportional to the shortest length of the crystal face in contact with the liquid paraffin and is rather independent of its form. Furthermore, crystal shape changes during dissolution, which is explained partly by the nonisometric dissolution of potassium ferricyanide crystal faces and partly by the nonconstancy of film thickness.
开发了一种模型系统，用于研究铁氰化钾单晶在液蜡-水界面的溶解行为。由于晶体在界面处的平衡位置与其大小无关，因此在界面处溶解的晶体的寿命完全由其初始大小及其在水相中的溶解速率决定。在溶解前，用显微镜测量每个晶体的尺寸。使用连续流动记录溶解装置，通过分光光度法测量溶解的铁氰化钾的质量流量。该系统中的溶解池安装在光具座上，通过将溶解的晶体投射到屏幕上，可以直观地跟踪它们。结果表明，晶体的寿命与与液蜡接触的晶面的最短长度成正比，并且与其形状相当无关。此外，晶体在溶解过程中形状会发生变化，这部分是由于铁氰化钾晶面的非等轴溶解，部分是由于膜厚度的不恒定。
