The solubility data, Hansen solubility parameter and dissolution thermodynamic properties of riluzole in twelve organic solvents

Abstract The solubility of riluzole in ethanol, n-propanol, n-butanol, n-pentanol, acetone, n-propyl acetate, n-amyl acetate, isopropyl acetate, N, N-dimethylacetamide (DMAC), 2-methoxyethanol, 2-propoxyethanol and acetonitrile was determined by laser detection under the external conditions of 278.15–323.15 K and 0.1 MPa. The experimental results imply that the solubility of riluzole in selected solvents is positively correlated with the temperature. The measured data was correlated with five thermodynamic models, including modified Apelblat model, λh model, NRTL model, UNIQUAC model, and Two-Suffix Margules model. And the best correlation was found in the modified Apelblat model. The solubility sequence of riluzole in selected solvents was analyzed by Hansen solubility parameter (HSP) which was calculated by using group contribution method. Meanwhile, the influence of solute–solvent interaction on the solubility of riluzole was investigated by using molecular dynamics simulation and solvent effect model (KAT-LSER model). Also, the dissolution thermodynamic properties of the dissolution process were computed and discussed via Van't hoff model. The results show that the solvent has a notable effect on the dissolution behavior of riluzole and this is an entropy-driven and endothermic process.