| or enhancement the low bioavailability of poorly water-soluble naproxen, three deep eutectic solvents (DESs)
obtained from betaine as a hydrogen bond acceptor and propylene glycol, ethylene glycol or glycerol as a
hydrogen bond donor (Bet/PG, Bet/EG or Bet/Gly DESs) are utilized from 0.0 to 1.0 mass fractions of DESs at T
= (293.15–313.15) K under atmospheric pressure (≈ 85 kPa). The solubility values tend to enhance with
enhancing mass fraction of each DES as well as increasing temperature and the maximum values are obtained in
the highest mass fraction of DESs at 313.15 K. Besides, the Hansen solubility parameters are used to predict the
selection of appropriate cosolvent system; the results indicated that the Bet/PG DES is a proper cosolvent for
naproxen solubilization. Moreover, the equilibrated solid phase crystal of naproxen with neat solvents is characterized with X-ray powder diffraction analysis to identify no polymorphic transformation, solvate formation or
crystal transition during the whole solvent crystallization process. In addition, the experimental solubilities are
correlated with the temperature dependency of traditional cosolvency models including Jouyban-Acree, Jouyban-Acree-van’t Hoff and modifed Wilson-van’t Hoff together with the activity coeffcient models of NRTL,
Wilson and UNIQUAC. The accuracies of the calculated solubilities are evaluated by calculation of the mean
relative deviation (MRD%) and the results suggested that the Jouyban-Acree (MRD% ≤ 8.9) along with the NRTL
activity coeffcient model (MRD% ≤ 2.0) are more accurate than the others. Finally, the respective apparent
thermodynamic quantities of the dissolution and mixing processes, namely Gibb’s energy, enthalpy, and entropy
are calculated based on the van’t Hoff and Gibbs equations |