Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

The solubility of antofloxacin hydrochloride in deep eutectic solvent (DES) aqueous solutions between choline chloride (ChCl) and p-toluenesulfonic acid (PTS), (ethanol + water) and (ethanol + acetonitrile) co-solvent mixtures were investigated by means of the isothermal dissolution equilibrium method at (273.15-318.15) K under pressure condition of 101.3 kPa. Experimental solubility was strongly increased more than about 560 folds in aqueous ChCl/PTS system with the increasing temperature and mass fraction of DES, and it is 404 times in (ethanol + water) and 60 times in (ethanol + acetonitrile). The solubility maximum 0.01226 (318.15 K, in mole fraction) was obtained in wDES = 0.6 of the aqueous ChCl/PTS DES. X-ray power diffraction (XPRD) was employed to examine the equilibrium solid phase samples of antofloxacin hydrochloride in three systems resulting in no polymorphic transformation, solvate formation or crystal transition compared to the raw sample. The modified Apelblat equation was exclusively used to correlate the equilibrium solubility. Results show that the RAD and RMSD highest were, 2.35x10-2 and 3.45x10-5, respectively. The modified Apelblat equation could be used to correlate the results. Data obtained elucidated that the ChCl/PTS DES is an effective additive for enhancing the antofloxacin hydrochloride solubility.