The solubility of β-arbutin (ARB) in 12 different monosolvents (methanol, ethanol, propanol, isopropanol, butyl alcohol, isobutanol, ethyleneglycol, acetone, 2-butanone, acetonitrile, methyl acetate, and ethyl acetate) from 283.15 to 323.15 K at atmospheric pressure was measured by gravimetric method. The solubility data show an increasing trend with increasing temperature. The solubility is related to many factors like polarity, H-bond, cohesive energy density, etc. The solubility of ARB was correlated by the Apelblat model, λh model, Van’t Hoff equation, and nonrandom two-liquid (NRTL) model. Also, the Apelblat model shows a better fitting result compared with other three models through calculating the value of ARD. Besides, the dissolution thermodynamic properties (the dissolution Gibbs energy, enthalpy, and entropy) were evaluated, which revealed that the dissolution of ARB was a spontaneous and exothermic process.

The thermodynamic solubility of γ-pyrazinamide in 13 solvents (methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, acetone, acetonitrile, water, 1,4-dioxane, methyl acetate, ethyl acetate, and n-propyl acetate) was measured by a dynamic method from 278.15 to 318.15 K. The results were modified by four models (λh equation, Apelblat equation, Wilson model, and nonrandom two-liquid (NRTL) model), and all of the relative standard deviation (RSD) values were less than 6%, indicating that the correlated data is in good agreement with the experiments. The thermodynamic parameters of mixing (Δmix H, Δmix G, and Δmix S) were calculated by the NRTL model. Furthermore, the physicochemical properties of different solvents were investigated to visualize the solvent effects. The results indicated that for the ester and alcohol systems, the “like dissolves like” principle and mass transfer rules were the main factors that affect the solubility, and for other solvents, hydrogen bond donor propensities played the key role.