Dissolution Process and Thermodynamic Model Correlation of Homovanillic Acid in Different Solvents and Intermolecular Force Analysis

Abstract

For insoluble drug compounds, co-solvent has been widely used as a very useful dissolution technology. The dissolution of homovanillic acid (HVA) in pure and mixed solvents over the temperature range of 273.15–318.15 K was studied. In a pure solvent, the maximum solubility at 318.15 K was obtained in ethanol (1.359 × 10–2 in mole fraction), followed by n-propanol (1.307 × 10–2), isopropanol (1.273 × 10–2), ethyl acetate (1.17 × 10–2), 1-butanol (1.017 × 10–2), i-butanol (9.504 × 10–3), acetonitrile (7.960 × 10–3), toluene (2.267 × 10–4), and cyclohexane (6.124 × 10–5). In a mixture of (toluene + isopropanol), it increased to a maximum value with the increasing concentration of isopropanol and then decreased at a certain temperature. The effect of solute–solvent intermolecular interactions on the solubility in pure and mixed solvents was presented in the form of the analysis of solvent properties using the KAT-LSER method. The function of solubility data, temperatures, and solvent composition was evaluated by the modified Apelblat equation, λh equation, and Jouyban–Acree model. The result of relative average deviation (RAD) indicates that the modified Apelblat equation and Jouyban–Acree model could provide a reasonable correlation in studied solvents.