A laser monitoring technique for determination of mesalazine solubility in propylene glycol and ethanol mixtures at various temperatures

Modeling of drug solubility and its experimental determination using automated techniques have great importance in the pharmaceutical industry. Mesalazine solubility was measured in a non-aqueous system of propylene glycol and ethanol at various temperatures using an updated laser-based monitoring combined with gravimetric measurement. The obtained solubility data were fitted to diverse cosolvency models including the van't Hoff, the mixture response surface, the Yalkowsky, the Jouyban-Acree, the Jouyban-Acree-van't Hoff, and the modified Wilson models, and the mean relative deviations of the predicted solubility data by the mentioned models were calculated. Furthermore, the apparent thermodynamic properties of mesalazine dissolution process were computed by using the van't Hoff and Gibbs equations. The combined usage of the automated solubility monitoring together with thermodynamic modeling is deemed as highly promising for the pharmaceutical industry and particular results of mesalazine add to a database of drug solubility. (C) 2020 Elsevier B.V. All rights reserved.