Acetaminophen solubility in aqueous solutions of betaine-propylene glycol natural deep eutectic solvent at different temperatures

This work reports the aqueous solubility of acetaminophen (ACP), a most traditionally used analgesics and antipyretic drug, in betaine/propylene glycol deep eutectic solvent (Bet/PG DES) as a green solvent at temperatures ranging from 293.15 K to 313.15 K and atmospheric pressure (approximate to 85 kPa). The ACP solubility in this solvent not only increases with increasing temperature, but also increases by increasing the DES portion reaching maximum values in the mixture of w(DES) = 0.90 at 313.15 K. The obtained experimental solubilities are accurately correlated with van't Hoff, Jouyban-Acree, Jouyban-Acree-van't Hoff, the modified Jouyban-Acree-van't Hoff, the mixture response surface, the combined nearly ideal binary solvent/Redlich-Kister, the Buchowski-Ksiazczak and modified Wilson models. The accuracy of each model is evaluated by computing the average relative deviations (ARD%) and the results confirm that the the mixture response surface model (ARD% = 1.78) has a better correlation performance in comparison with the other models. Besides, thermodynamic behavior of ACP in the aqueous solution of Bet/PG DES is described with calculation of thermodynamic functions including Gibbs energy, enthalpy, and entropy of dissolution achieved from the van't Hoff and Gibbs equations. The results revealed that the ACP dissolution is an endothermic and entropy-driven process. (C) 2021 Elsevier B.V. All rights reserved.