Vol. 7, Issue 2, Part E (2025)

The compatibility of Active Pharmaceutical Ingredients (APIs) with excipients is crucial for maintaining the stability, safety, and effectiveness of formulations. This study investigates drug-excipient interactions during the pre-formulation phase for three dipeptidyl peptidase-4 (DPP-4) inhibitors: Sitagliptin, Linagliptin, and Alogliptin. A variety of analytical methods, including Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), High-performance Liquid Chromatography (HPLC), and X-Ray Diffraction (XRD), were employed to detect possible physicochemical interactions. Each drug was separately combined with common excipients and analyzed through thermal and spectral methods. The results revealed varying degrees of compatibility, with some excipients causing observable changes in thermal properties or crystallinity, indicating possible interactions. Overall, the mixtures remained stable at the tested temperatures, and the selected excipients generally interacted favorably with the APIs. These findings offer important guidance for excipient selection in formulation development, supporting the stability and effectiveness of DPP-4 inhibitor-based medications.