Solubility Measurement and Thermodynamic Modeling of Bifendate in 13 Pure Solvents at Temperatures from 293.15 to 333.15 K

Abstract

This study aimed to determine the solubility of bifendate (a drug used in the treatment of chronic hepatitis) in 13 different pure organic solvents (methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, isopropanol, methyl acetate, ethyl acetate, 1-propyl acetate, 1-butyl acetate, 1-pentyl acetate, acetonitrile, and acetone) through the gravimetric method in the range 293.15–333.15 K. The physical stability of bifendate was evaluated by comparing power X-ray diffraction patterns before and after achieving equilibrium. The melting temperature and enthalpy were measured via the differential scanning calorimetry method. These experimental data were used to regress PC-SAFT (Perturbed-Chain Statistical Associating Fluid Theory) pure component parameters of the drug. Furthermore, PC-SAFT combined with solid–liquid equilibrium theory was employed to calculate the solubility of the drug in 13 pure solvents. Combined with our previous research, this study demonstrated that PC-SAFT accurately predicted the solubility of different categories of drugs in various solvent systems. Thus, PC-SAFT was a useful tool for pharmaceutical scientists in drug research and development and could significantly save time and economic cost by reducing trial-and-error experiments.