Dipeptidyl peptidase 4 (DPP-4), well known as the T-cell antigen CD26 enzyme which, was discovered in the year of 1966 by Hopsu-Havu and Glenner. The enzyme gained considerable attention due to its vital functions, such as (1) deactivation of the incretin hormone, which is responsible for insulin catabolism, (2) hydrolyzes of opioid peptides engaged in pain modulation, etc. Moreover, DPP-4 also acts as a carrier protein and ligand for a variety of extracellular and intracellular substrates. The Finding of DPP-4 inhibitors is the newer approach to treating numerous disorders/ diseases, for example, coronary heart disease, heart failure, stroke, and Diabetes mellitus (DM). The outcomes of studies carried out in the past few decades revealed that Gliptins (DPP-4 inhibitors) is a more promising candidate than conventional hypoglycaemic agents, as the former can be taken in monotherapy once a week or conjointly with another hypoglycaemic agent. By considering all favorable properties of DPP-4 inhibitors, this excerpt was written with the primary focused on the clinically approved, orally acting Gliptin class of drugs, with an emphasizing on their conventional, modern as well as patented methods of intermediates and final product development.

二肽基肽酶 4 (DPP-4)，众所周知的 T 细胞抗原 CD26 酶，由 Hopsu-Havu 和 Glenner 于 1966 年发现。该酶因其重要功能而受到广泛关注，例如（1）使负责胰岛素分解代谢的肠促胰岛素激素失活，（2）水解参与疼痛调节的阿片肽等。此外，DPP-4 还发挥作用作为多种细胞外和细胞内底物的载体蛋白和配体。 DPP-4 抑制剂的发现是治疗多种病症/疾病的新方法，例如冠心病、心力衰竭、中风和糖尿病 (DM)。过去几十年的研究结果表明，格列汀（DPP-4抑制剂）是比传统降血糖药物更有前景的候选药物，因为前者可以每周一次单独治疗，也可以与另一种降血糖药物联用。考虑到 DPP-4 抑制剂的所有有利特性，本摘录主要关注临床批准的口服格列汀类药物，重点介绍其传统、现代以及专利的中间体和最终产品开发方法。