Solid-state landscape and biopharmaceutical implications of novel metformin-based salts

Metformin hydrochloride (MET-HCl) is a widely prescribed antihyperglycemic drug for the non-insulin-dependent diabetes mellitus treatment. Since the prolonged use of MET-HCl may cause gastrointestinal intolerance, we have focused on expanding the solid-state landscape of MET, designing three novel MET salts with saccharin, maleic and malonic acids. These multicomponent systems named metformin maleate (MET-MAL), metformin malonate (MET-MLN), and metformin saccharinate (MET-SAC) have been prepared via supramolecular synthesis by slow evaporation method and characterized by X-ray diffraction (SCXRD, PXRD), spectroscopic (FT-IR and H-1 NMR) and thermal (TG, DSC, HSM) techniques. The biopharmaceutical profile of these salts, including the MET-HCl, has been assessed. All of them were less soluble, with a slower dissolution rate, and with a resemble permeation capacity over MET-HCl. These results demonstrate the potential of these solid forms regarding the enhanced API candidates for new antidiabetic solid formulations.