Characterization of metformin by-products under photolysis, photocatalysis, ozonation and chlorination by high-performance liquid chromatography coupled to high-resolution mass spectrometry.

Rationale: Metformin (MTF) is the most widely prescribed drug for the treatment of patients with type 2 diabetes. Studies involving the removal of MTF from aqueous solutions and detailed information regarding the overall degradation process are scarce.

Methods: The degradation of MTF in aqueous solution induced by direct photolysis, photocatalysis, ozonation and chlorination was evaluated.