The object is to research the solid liquid phase of enalapril maleate and its intermediate enalapril hydride in pure solvent. Within the investigated temperature range, the mole fraction solubility data in the selected solvents increase with the increasing temperature. The solubility of enalapril hydride in different solvents decreases according to the order ethyl acetate > acetone > ethanol > n-octanol > isopropanol > acetonitrile, while enalapril maleate obeys the order ethyl acetate > acetone > ethanol > acetonitrile > n-octanol > isopropanol. The experimental solubility data of enalapril hydride and enalapril maleate in those solvents were correlated by the modified Apelblat equation, Buchowski-Ksiazaczak lambda h equation, and Wilson equation. The maximum values of root-mean-square deviation (RMSD) and relative average deviation (RAD) obtained by the three equations were 1.48 X 10(-4), 3.32% (enalapril hydride) and 2.82 x 10(-4), 4.36% (enalapril maleate), respectively. It was found from the RMSD value that the modified Apelblat equation is more suitable to describe the solubility behavior of enalapril hydride and enalapril maleate in these solvents.