Processes for reducing the amount of impurities, especially α,β-unsaturated ketones (ABUK), in materials containing morphine. Novel compounds, namely low ABUK morphine sulfate methanolic solvate, and a novel crystal form are also described. The method for making morphine sulfate methanolic solvate comprises mixing a morphine free base composition with methanol to form a solution and adding a liquid comprising sulfuric acid to the solution to form a morphine sulfate methanolic solvate precipitate. A method of making a morphine sulfate compound comprises drying the morphine sulfate methanolic solvate in the presence of water vapor, such that methanol molecules are removed and replaced with water vapor molecules. A composition for treating pain comprises the morphine sulfate compound and at least one pharmaceutically acceptable excipient. A method for treating pain comprises administering to a patient in need thereof the composition comprising the morphine sulfate compound and at least one pharmaceutically acceptable excipient.