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

Abstract

Currently, deep eutectic solvents (DESs) have gained considerable attention due to their wide range of investigational 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 DESs, 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 indomethacin 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.