Solubility Determination and Modeling for Artesunate in Binary Solvent Mixtures of Methanol, Ethanol, Isopropanol, and Propylene Glycol + Water

Artesunate is dissolved in an aqueous solution of several organic solvents (methanol, ethanol, isopropanol, and PG), and the mole fraction of artesunate is determined by the static method. When the system reaches equilibrium, the range of system temperature is 278.15–318.15 K and the pressure environment is 101.1 kPa. When the temperature is constant, the equilibrium mole fraction of artesunate is proportional to the mass percentage of organic solvents, and the relationship between artesunate solubility and temperature is the same as before under certain conditions of the organic solvent component. When the external conditions are the same, artesunate is more likely to dissolve in the ethanol + water mixture than in several other systems. Besides, three classical mixed solvent thermodynamic equations—Jouyban–Acree model, van't Hoff–Jouyban–Acree model, and Apelblat–Jouyban–Acree model—are applied to calculate the equilibrium mole fraction of artesunate. The maximum value of average relative deviations (ARD) obtained during the calculation is 0.83%. The experimentally measured data on artesunate has different general meanings for the expansion of application and production in the pharmaceutical field and provides theoretical data for its industrial production.