Solvation of Oxytetracycline Hydrochloride in Ethanol-Water Mixed Solvents.
The aim of this study was to determine the thermodynamic functions, Gibbs energy, enthalpy and entropy for the solution processes of oxytetracycline hydrochloride in the mixed solvent (ethanol+water) from solubility values obtained at temperatures ranging from 293.15 K to 308.15 K. The respective thermodynamic functions for mixing and solvation processes as well as the activity coefficients for the solute were calculated. The experimental results enable us to estimate the value of thermodynamic solubility product, Ksp(th), of oxytetracycline hydrochloride in the mixed solvent. In addition, Gibbs energy, enthalpy, entropy for the solution processes and free energies of transfer of oxytetracycline hydrochloride from water to ethanol solutions.
Esam A Gomaa, Elsayed M Abou Elleef and Elsayed T Helmy