Effect of choline-based ionic liquids as novel green solvents on the aqueous solubility enhancement and thermodynamic properties of acetaminophen

A highly efficient and ecofriendly co-solvency method using choline-based ionic liquids (ILs) as novel green solvents was developed to enhance the aqueous solubility of acetaminophen (ACP). ACP is a drug that is widely used as an antipyretic analgesic in clinical practice and its paediatric use is common. In this study the solubility of ACP in aqueous choline lactate (ChLa) and choline bitartrate (ChBi) solutions were measured at different temperatures for the first time. The temperature and solvent composition dependence of ACP solubility was analyzed through the some important semi-empirical and activity coefficient models acquiring the average relative deviation percent as e-NRTL (0.39%) < Wilson (1.40%) < Apelblat (1.86%) < λh (Buchowski) (2.34%) < Yalkowsky (4.39%) for correlative investigations. We also examined the intermolecular interactions between ACP and co-solvents using thermodynamic properties including volumetric and compressibility properties based on density and speed of sound measurements at experimental temperatures. Thermodynamic parameters results show that there are strong interactions between ACP and ILs. Finally these results were further confirmed by the obtained solubility data.