Solubility and mixing thermodynamic properties of levamisole hydrochloride in twelve pure solvents at various temperatures

Abstract

The solubility of solid compounds and active pharmaceutical ingredient in different solvents is important for its crystallization and purification industry. In this work, by using a laser dynamic method, the solubility of levamisole hydrochloride in methanol (MT), ethanol (ET), isopropanol (IPA), n-propanol (NPA), n-butanol (NBA), 2-butanol (SBA), isobutanol (IBA), n-pentanol (NPT), 3-methyl-1-butanol (IAA) and n-hexanol (NHA) from (283.15 to 323.15) K, dimethyl sulfoxide (DMSO) from (293.15 to 333.15) K and water from (283.15 to 308.15) K were measured under atmospheric pressure. The measured results showed that the experimental solubility of levamisole hydrochloride increased non-linearly with the temperature in the studied pure solvents. The measured solubility data were all correlated by the Yaws model equation, non-random two liquid (NRTL) model equation, universal quasi chemical (UNIQUAC) model equation, Wilson model equation and λh equation. Besides, the logarithm of activity coefficient of levamisole hydrochloride (lnγ1) were calculated with the NRTL model, Wilson model and UNIQUAC model. The maximum relative average deviation (ARD) was 0.2008, the maximum root-mean-square deviation (RMSD) was 0.0089. Basically speaking, the measured solubility data in this study can be well correlated with the five thermodynamic models. Based on the solubility data and Wilson model, the mixing entropy, mixing enthalpy and mixing Gibbs energy were evaluated. The logarithm of the solute activity coefficients lnγ1in the studied saturated solutions were calculated, The positive values of lnγ1 means that the repulsive interactions exist between levamisole hydrochloride and the corresponding solvents (NBA, NPA, NHA, IPA, IBA, SBA and IAA), and the solutions system positively deviate from Raoult’s law; The negative values of lnγ1 means that the attractive interactions exist between levamisole hydrochloride and the corresponding solvents (MT, ET, NPT, DMSO and water), and the solutions system minus deviate from Raoult’s law. This work can give fundamental data for the crystallization and purification of levamisole hydrochloride.