Sitagliptin 是一种有效的DPP4抑制剂，在 Caco-2 细胞中，IC50值为 19 nM。它是一种新型口服降糖药，可单独使用或与二甲双胍或噻唑烷二酮联合用于治疗 2 型糖尿病。

Sitagliptin, a new oral hypoglycemic (anti-diabetic drug), is a new dipeptidyl peptidase-4 (DPP-4) inhibitor. This enzyme-inhibiting drug is used either alone or in combination with metformin or thiazolidinedione for treatment of type 2 diabetes mellitus. The drug can competitively inhibit a protein/enzyme and DPP-4, that leads to an incremental amount of active incretins (GLP-1 and GIP), the diminished amount of release of glucagon and increased release of insulin.

Sitagliptin phosphate exhibits a potent inhibitory effect on DPP-4 with IC50 of 19 nM from Caco-2 cell extracts[1]. Sitagliptin reduces in vitro migration of isolated splenic CD4 T-cells via a pathway involving cAMP/PKA/Rac1 activation[2]. Stagliptin exerts a novel, direct action in order to stimulate GLP-1 secretion by the intestinal L cell through a DPP-4-independent, protein kinase A- and MEK-ERK1/2-dependent pathway. It reduces the effect of autoimmunity on graft survival[3].

In vivo, the ED50 value of sitagliptin phosphate for inhibition of plasma DPP-4 activity is calculated to be 2.3 mg/kg 7 hour postdose and 30 mg/kg 24 hour postdose in freely fed Han-Wistar rats[1]. The streptozotocin-induced type 1 diabetes mouse model exhibits elevated DPP-4 levels in the plasma that can be substantially inhibited in mice on an Sitagliptin phosphate diet. This is achieved by a positive effect on the regulation of hyperglycemia, potentially through prolongation of islet graft survival[4]. The plasma clearance and volume of distribution of Sitagliptin phosphate are higher in rats (40-48 mL/min/kg, 7-9 L/kg) than in dogs (9 mL/min/kg, 3 L/kg); and its half-life is 2 hours in rats which is shorter compared to 4 hours in dogs[5].

DPP-4 is extracted from confluent Caco-2 cells. After 5 minutes of incubation at room temperature with lysis buffer (10 mM Tris-HCl, 150 mM NaCl, 0.04 U/mL aprotinin, 0.5% Nonidet P40, pH 8.0), cells are centrifuged at 35,000 g at 4°C for 30 minutes, and the supernatant is stored at -80°C. Assays are performed by mixing 20 μL of appropriate compound dilutions with 50 μL of the substrate for the DPP-4 enzyme, H-Ala-Pro-7-amido-4-trifluoromethylcoumarin (final concentration in the assay, 100 μM) and 30 μL of the Caco-2 cell extract (diluted 1000-fold with 100 mM Tris-HCl, 100 mM NaCl, pH 7.8). Plates are incubated at room temperature for 1 hour, and fluorescence is measured at excitation/emission wavelengths of 405/535 nm using a SpectraMax GeminiXS. Dissociation kinetics of inhibitors from the DPP-4 enzyme is determined after a 1-hour preincubation of Caco-2 cell extracts with high inhibitor concentrations (30 nM for BI 1356, 3 μM for vildagliptin). The enzymatic reaction is started by adding the substrate H-Ala-Pro-7-amido-4-trifluoromethylcoumarin after a 3000-fold dilution of the preincubation mixture with assay buffer. Under these conditions, the difference in DPP-4 activity at a certain time point in the presence or absence of an inhibitor reflects the amount of this inhibitor still bound to the DPP-4 enzyme. Maximal reaction rates (fluorescence units/seconds ×1000) at 10-minute intervals are calculated using the SoftMax software of the SpectraMax and corrected for the rate of an uninhibited reaction [(vcontrol-vinhibitor)/vcontrol].

CD4T-cells are plated on membrane inserts in serum-free RPMI 1640, and cell migration is assayed using Transwell chambers (Corning), in the presence or absence of purified porcine kidney DPP-4 (32.1 units/mg; 100 mU/mL final concentration) and DPP-4 inhibitor (100 μM). After 1 hour, cells on the upper surface are removed mechanically, and cells that have migrated into the lower compartment are counted. The extent of migration is expressed relative to the control sample.

486460-32-6

C16H15F6N5O

407.32

西格列汀;MK0431;西他列汀

DMSO:198.9 mM
Powder: -20°C for 3 years
In solvent: -80°C for 2 years