Table 1.

The features of approved dipeptidyl peptidase 4 inhibitors (DPP4i).

DPP4i	Chemistry	Metabolism	Half-Life	Elimination Method
Sitagliptin	β-amino acid based	Minimal	12.5 h	Predominantly (>80%) renal
Vildagliptin	Cyanopyrrolidine	Hydrolysis (cytochromeindependent) to form an inactive metabolite	~2 h	Metabolism (parent) and renal (metabolite)
Saxagliptin	Cyanopyrrolidine	Hydrolysis (cytochrome P450 3A4 or P450 3A5) to form an activemetabolite	2.5 h (parent), 3 h (metabolite)	Metabolism (parent) and renal (metabolite)
Alogliptin	Modified pyrimidinedione	Minimal	20 h	Predominantly (>70%) renal
Linagliptin	Xanthine based	Minimal	~12 h (effective), >100 h (terminal)	Predominantly biliary (<6% renal)