Solubility improvement of indomethacin by novel biodegradable eutectic solvents based on protic ionic liquid monoethanolamine carboxylate/ethylene glycol

Currently, eutectic solvents and deep eutectic solvents (DESs) have gained considerable attention due to their wide range of academic and technological domains. Meanwhile, DESs based on ionic liquids (ILs) are a new generation of green solvents that have unique properties. The goal of this study was to investigate the sparingly soluble drug indomethacin (IMC) in three monoethanolamine carboxylate-based eutectic solvents with ethylene glycol (EG), including monoethanolamine propionate/ethylene glycol (MEAP/EG), monoethanolamine lactate/ ethylene glycol (MEAL/EG), and monoethanolamine acetate/ethylene glycol (MEAA/EG). The shake flask method was employed in this investigation at an atmospheric pressure of 86.6 kPa and temperature range of T= (298.15-313.15) K. The outcomes demonstrated that the solubility of IMC was obtained approximately 600-fold more than its solubility in water. Numerous thermodynamic models, including the Jouyban-Acree model, the Van't Hoff-Jouyban-Acree model, the Modified Apelblat-Jouyban-Acree model, and the activity coefficient models Wilson and e-NRTL, accurately correlated the solubility data which their performance order is as follows: Modified Apelblat - Jouyban - Acree > Van't Hoff - Jouyban - Acree > Wilson > Modified Apelblat equation > e-NRTL > Jouyban-Acree model. Finally, Van't Hoff and Gibbs equations have been applied the apparent thermodynamic properties of dissolution in the investigated systems which the dissolution process is endothermic and enthalpy-driven in all of the co-solvents which have been utilized.