Linagliptin (CAS: 668270-12-0, C₂₅H₂₈N₈O₂) is a selective dipeptidyl peptidase-4 (DPP-4) inhibitor utilized as a high-purity (≥98%) reference standard and active pharmaceutical ingredient (API) in pharmaceutical research, synthesis, and analytical applications for type 2 diabetes mellitus studies.

It functions by increasing incretin hormone levels (e.g., GLP-1, GIP), which enhance glucose-dependent insulin secretion and suppress glucagon release postprandially, aiding investigations into glycemic control mechanisms.

Beneficial in research models of renal impairment due to no dosage adjustment needs. Commonly studied in combination with agents like metformin. Its solid form (mp 195-210°C) supports diverse lab uses including HPLC standards, bioassays, and drug development.

Linagliptin serves as a valuable specialty chemical tool for advancing antidiabetic therapies with a favorable pharmacokinetic profile.