Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

ABSTRACT

The solubility of econazole nitrate (racemic mixture) in organic solvents is of clear importance for the design of separation processes and further theoretical studies. In this work, the solubilities of econazole nitrate in methanol, ethanol, n-butanol, isopropanol, ethyl acetate, 2-butanone, 3-methyl-1-butanol, acetonitrile, 1,4-dioxane, N,N-dimethylformamide (DMF), 1-methyl-2-pyrrolidinone (NMP) and acetone were determined at the temperatures from 278.15 K to 318.15 K under atmosphere pressure (p = 101.2 kPa) by high-performance liquid chromatography (HPLC). It was found that the econazole nitrate solubilities in mole fraction in selected solvents increased with the increase in temperature. At a given temperature, they obeyed the following order from high to low in different solvents: NMP greater than DMF greater than methanol greater than 2-butanone greater than acetone greater than (3-methyl-1-butanol, ethanol) greater than acetonitrile greater than n-butanol greater than isopropanol greater than 1,4-dioxane greater than ethyl acetate. The experimental solubility data were correlated with the modified Apelblat equation and the Buchowski Ksia^2 _zczak kh equation. The calculated solubilities using the modified Apelblat solubility model were in better agreement with the experimental values. The largest percentage of average relative deviation was 1.53% for solubility of econazole nitrate in isopropanol calculated with the kh equation, and the maximum value of root-mean-square deviation was 2.11 10 4. Based on the modified Apelblat equation, the apparent dissolution enthalpies of econazole nitrate in twelve pure solvent were derived. The results indicate that the dissolution of econazole nitrate in all studied cases is endothermic process.