Synthesis, crystallization and characterization of diastereomeric salts formed by ephedrine and malic acid in water

► Discovery of a simple system consisting of 7 different salt forms of L-Eph. ► Successful salt screening by dry/wet grinding and RH controlled crystallization. ► 1:1 stoichiometry favours anhydrate formation. ► 2:1 stoichiometry tends to give monohydrate forms. ► 2:1 LD trihydrate is stable only at high relative humidity (>50%).