title: Disposition of the dipeptidyl peptidase 4 inhibitor sitagliptin in rats and dogs.
abstract: The pharmacokinetics, metabolism, and excretion of sitagliptin [MK-0431; (2R)-4-oxo-4-[3-(trifluoromethyl)-5,6-dihydro[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl]-1-(2,4,5-trifluorophenyl)butan-2-amine], a potent dipeptidyl peptidase 4 inhibitor, were evaluated in male Sprague-Dawley rats and beagle dogs. The plasma clearance and volume of distribution of sitagliptin were higher in rats (40-48 ml/min/kg, 7-9 l/kg) than in dogs ( approximately 9 ml/min/kg, approximately 3 l/kg), and its half-life was shorter in rats, approximately 2 h compared with approximately 4 h in dogs. Sitagliptin was absorbed rapidly after oral administration of a solution of the phosphate salt. The absolute oral bioavailability was high, and the pharmacokinetics were fairly dose-proportional. After administration of [(14)C]sitagliptin, parent drug was the major radioactive component in rat and dog plasma, urine, bile, and feces. Sitagliptin was eliminated primarily by renal excretion of parent drug; biliary excretion was an important pathway in rats, whereas metabolism was minimal in both species in vitro and in vivo. Approximately 10 to 16% of the radiolabeled dose was recovered in the rat and dog excreta as phase I and II metabolites, which were formed by N-sulfation, N-carbamoyl glucuronidation, hydroxylation of the triazolopiperazine ring, and oxidative desaturation of the piperazine ring followed by cyclization via the primary amine. The renal clearance of unbound drug in rats, 32 to 39 ml/min/kg, far exceeded the glomerular filtration rate, indicative of active renal elimination of parent drug.
authors.affiliation: Merck Research Laboratories, P.O. Box 2000, Rahway, NJ 07065, USA.
authors.forename: Maria G
authors.initials: MG
authors.lastname: Beconi
authors.forename: James R
authors.initials: JR
authors.lastname: Reed
authors.forename: Yohannes
authors.initials: Y
authors.lastname: Teffera
authors.forename: Yuan-Qing
authors.initials: YQ
authors.lastname: Xia
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Kochansky
authors.forename: David Q
authors.initials: DQ
authors.lastname: Liu
authors.forename: Shiyao
authors.initials: S
authors.lastname: Xu
authors.forename: Charles S
authors.initials: CS
authors.lastname: Elmore
authors.forename: Suzanne
authors.initials: S
authors.lastname: Ciccotto
authors.forename: Donald F
authors.initials: DF
authors.lastname: Hora
authors.forename: Ralph A
authors.initials: RA
authors.lastname: Stearns
authors.forename: Stella H
authors.initials: SH
authors.lastname: Vincent
mesh_terms: D000243:Adenosine Deaminase / Q000378:metabolism; D058892:Adenosine Deaminase Inhibitors; D000284:Administration, Oral; D000818:Animals; D001646:Bile / Q000378:metabolism; D001682:Biological Availability; D001711:Biotransformation; D003500:Cyclization; D018819:Dipeptidyl Peptidase 4 / Q000378:metabolism; D054873:Dipeptidyl-Peptidase IV Inhibitors; D004285:Dogs; D004791:Enzyme Inhibitors / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D005243:Feces / Q000737:chemistry; D020719:Glucuronides / Q000378:metabolism; D006023:Glycoproteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D000882:Haplorhini; D006801:Humans; D006900:Hydroxylation; D007004:Hypoglycemic Agents / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D066298:In Vitro Techniques; D007668:Kidney / Q000378:metabolism; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism; D015394:Molecular Structure; D010084:Oxidation-Reduction; D011485:Protein Binding; D011719:Pyrazines / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D051381:Rats; D017207:Rats, Sprague-Dawley; D000068900:Sitagliptin Phosphate; D013045:Species Specificity; D013463:Sulfuric Acid Esters / Q000378:metabolism; D014230:Triazoles / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine
chemical_list: D058892:Adenosine Deaminase Inhibitors; D054873:Dipeptidyl-Peptidase IV Inhibitors; D004791:Enzyme Inhibitors; D020719:Glucuronides; D006023:Glycoproteins; D007004:Hypoglycemic Agents; D011719:Pyrazines; D013463:Sulfuric Acid Esters; D014230:Triazoles; C042807:DPP4 protein, human; D018819:Dipeptidyl Peptidase 4; D000243:Adenosine Deaminase; D000068900:Sitagliptin Phosphate