Characterization of drug-drug salt forms of metformin and aspirin with improved physicochemical properties

A drug-drug salt was prepared consisting of metformin and aspirin with two crystalline phases characterized. A hydrophilic surface induced recrystallization mechanism was supposed for the transition from anhydrate to hemihydrate. The modulated solubility properties of the dual drug would help to overcome the associated gastrointestinal side effects to some extent.