Williams N A, Amidon G L
J Pharm Sci. 1984 Jan;73(1):9-13. doi: 10.1002/jps.2600730104.
An approach is developed by which the solubility of an organic compound in mixed solvents may be estimated. In this approach, an expression for the excess Gibbs free energy of mixing for multicomponent solvent systems was used to obtain parameters characteristic of the interaction between the solvents. A fairly simple equation which predicts the solubility of a solute in a binary solvent system over the entire solvent composition range was then derived. The equation may be partitioned into terms that contain (a) pure solvent solubilities, (b) solvent-solvent interaction contributions, and (c) contributions from the solute-mixed solvent interactions. The required data are the molar volume of the solute, the pure solvent solubilities, and, theoretically, one experimentally determined solubility in a solvent mixture. The equation can be easily extended for systems with three or more solvents.
开发了一种方法，通过该方法可以估算有机化合物在混合溶剂中的溶解度。在这种方法中，使用多组分溶剂系统混合的过量吉布斯自由能表达式来获得溶剂间相互作用的特征参数。然后推导出一个相当简单的方程，该方程可预测溶质在整个溶剂组成范围内的二元溶剂系统中的溶解度。该方程可以分为包含（a）纯溶剂溶解度、（b）溶剂-溶剂相互作用贡献以及（c）溶质-混合溶剂相互作用贡献的项。所需数据是溶质的摩尔体积、纯溶剂溶解度，理论上还有在溶剂混合物中的一个实验测定溶解度。该方程可以很容易地扩展到具有三种或更多种溶剂的系统。
