sitagliptin phosphate monohydrate is the phosphate salt of its active component, sitagliptin, with one molecule of water. sitagliptin is a potent inhibitor of dipeptidyl peptidase 4 (dpp-4), an enzyme catalyzing the cleavage of peptides with an n-terminal alanine or proline amino acid residue, that selectively inhibits dpp-4 with 50% inhibition concentration ic50 value of 18 nm and shows no affinity towards other ddp enzymes (such as ddp-8 and ddp-9). the inhibition of dpp4 by sitagliptin has been found to be mediated by increasing levels of two dpp-4 substrates, including glucagon-like peptide-1 (glp-1) and gastric inhibitory polypeptide (gip). sitagliptin is currently being investigated in the treatment of type ii diabetes.gallwitz b. review of sitagliptin phosphate: a novel treatment for type 2 diabetes. vasc health risk manag. 2007;3(2):203-10.
