Modeling the solubility of pharmaceuticals in pure solvents and solvent mixtures for drug process design.

The knowledge of the solubility of pharmaceuticals in pure solvents and solvent mixtures is crucial for designing the crystallization process of drug substances. The first step in finding optimal crystallization conditions is usually a solvent screening. Since experiments are very time consuming, a model which allows for solubility predictions in pure solvents and solvent mixtures based only on a small amount of experimental data is required. In this work, we investigated the applicability of the thermodynamic model perturbed-chain statistical associating fluid theory (PC-SAFT) to correlate and to predict the solubility of exemplary five typical drug substances and intermediates (paracetamol, ibuprofen, sulfadiazine, p-hydroxyphenylacetic acid, and p-aminophenylacetic acid) in pure solvents and solvent mixtures.