Abstract
Dipeptidyl peptidase IV (DPP-IV) inhibitor has been expected to be a new class of anti-diabetic agent. The present study was designed to characterize the pharmacological profiles of CMD-05, a novel DPP-IV inhibitor discovered in our laboratory, in vitro and in vivo. The IC50 of CMD-05 on DPP-IV inhibitory activity was approximately 12 nM while vildagliptin was 3.5 nM in vitro. In diabetes rat model established by high fat diet/low dose streptozotocin, CMD-05 inhibited DPP-IV activity, significantly improved glucose tolerance, increased GLP-1 and insulin levels in plasma. Long-term administration of CMD-05 decreased HbA1c and TG levels and improved the islet function without significantly effect on body weight. Furthermore, CMD-05 reduced INS-1 cell apoptosis and increased GLP-1 secretion in NCI-H716. After oral administration, CMD-05 reached peak concentration at 30 min with half-life of 288 minutes and the inhibitory rate of DPP-IV greater than 50% lasted for 15 h. In fasted normal rats, CMD-05 didn't cause significant hypoglycemia. CMD-05 had a lower cytotoxicity than vildagliptin in vitro and its maximum tolerance dose in mice is beyond 2000 mg/kg. These results indicated that CMD-05 has similar activity with vildagliptin in vivo and has a much longer half-life and lower cytotoxicity than vildagliptin.