Determination and correlation of solubility of linezolid form II in different pure and binary solvents

The solubility data of linezolid form II in five pure solvents (water, methanol, ethanol, 1-propanol, 2-propanol) and a binary (water + methanol) solvent were determined among the temperature range from 283.15 K to 318.15 K under atmospheric pressure. The results indicated that the solubility increased with the temperature increasing. Seven thermodynamic models were used here to correlate the experimental solubility data. Through the comparison of the experimental data in pure solvents with the calculated results, we found that the modified Apelblat equation fit the experimental data best. Furthermore, the density functional theory (DFT) calculations showed that the solubility in different solvents related to the interaction strength between the linezolid and the solvent molecules. Finally, the molar enthalpy change, molar entropy change and molar Gibbs free energy change of dissolution of linezolid in the different solvents were also calculated by van't Hoff equation in this paper.