Linagliptin, a xanthine derivative, is a highly potent, selective, long-acting and orally bioavailable DPP-4 inhibitor for the treatment of type 2 diabetes. During the process development of linagliptin, five new process-related impurities were detected by high performance liquid chromatography (HPLC). All these impurities were identified, synthesized, and subsequently characterized by their respective spectral data (MS, HRMS, 1H-NMR, 13C-NMR and IR) as described in this article. The identification of these impurities should be useful for quality control and the validation of the analytical method in the manufacture of linagliptin.
