DPP-4 (IC50 = 18 nM)

Sitagliptin phosphate shows a strong inhibitory action on DPP-4 from extracts of Caco-2 cells, with an IC50 of 19 nM[1]. Via a mechanism involving cAMP/PKA/Rac1 activation, sitagliptin decreases the in vitro migration of isolated splenic CD4 T-cells[2]. A recent study shows that sitagliptin stimulates intestinal L cell GLP-1 secretion through a novel, direct action that is dependent on MEK-ERK1/2 and protein kinase A, but not on DPP-4. As a result, it lessens the impact of autoimmunity on graft survival[3].

For sitagliptin phosphate to inhibit plasma DPP-4 activity in vivo, the ED50 value in freely fed Han-Wistar rats is estimated to be 2.3 mg/kg seven hours postdose and 30 mg/kg twenty-four hours postdose[1]. Elevated DPP-4 levels in the plasma are seen in the streptozotocin-induced type 1 diabetes mouse model, but these levels can be significantly reduced in mice fed Sitagliptin phosphate. This is accomplished by possibly prolonging islet graft survival through a beneficial effect on the regulation of hyperglycemia[4]. Sitagliptin phosphate's plasma clearance and volume of distribution are higher in rats (40–48 mL/min/kg, 7-9 L/kg) than in dogs (9 mL/min/kg, 3 L/kg); additionally, rats' half-lives are shorter—two hours versus four hours in dogs[5].

Confluent Caco-2 cells are used to extract DPP-4. Following a 5-minute room temperature incubation period with lysis buffer (10 mM Tris-HCl, 150 mM NaCl, 0.04 U/mL aprotinin, 0.5% Nonidet P40, pH 8.0), the cells are centrifuged at 35,000 g for 30 minutes at 4 °C, and the supernatant is kept at -80°C afterwards. Twenty microliters of suitable compound dilutions are combined with fifty microliters of H-Ala-Pro-7-amido-4-trifluoromethylcoumarin (final concentration in the assay: 100 microliters) as the substrate for the DPP-4 enzyme, and thirty microliters of the Caco-2 cell extract (diluted 1000 times with 100 mM Tris-HCl, 100 mM NaCl, pH 7.8). Fluorescence is measured using a SpectraMax GeminiXS at excitation/emission wavelengths of 405/535 nm after plates are incubated for one hour at room temperature. After exposing Caco-2 cell extracts to high inhibitor concentrations (30 nM for BI 1356 and 3 μM for vildagliptin) for one hour, the dissociation kinetics of the inhibitors from the DPP-4 enzyme are ascertained. Once the preincubation mixture has been diluted 3000-fold with assay buffer, the enzymatic reaction is initiated by adding the substrate, H-Ala-Pro-7-amido-4-trifluoromethylcoumarini. The amount of an inhibitor that is still bound to the DPP-4 enzyme is indicated by the difference in DPP-4 activity at a given time in the presence or absence of the inhibitor. Using the SoftMax software of the SpectraMax, maximum reaction rates (fluorescence units/seconds × 1000) are calculated at 10-minute intervals and corrected for the rate of an uninhibited reaction [(vcontrol-vinhibitor)/vcontrol].

Membrane inserts containing CD4T-cells are plated in serum-free RPMI 1640. Cell migration is measured using Corning Transwell chambers, either with or without DPP-4 inhibitor (100 μM) and purified porcine kidney DPP-4 (32.1 units/mg; final concentration of 100 mU/mL). Following an hour, cells that have moved into the lower compartment are counted and those on the upper surface are mechanically removed. The expression for the amount of migration is in relation to the control sample.

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Glucagon-like peptide-1 (GLP-1) is an incretin hormone secreted into the circulation by the intestinal L cell. The dipeptidylpeptidase-IV (DPP-IV) inhibitor, sitagliptin, prevents GLP-1 degradation and is used in the clinic to treat patients with type 2 diabetes mellitus, leading to improved glycated hemoglobin levels. When the effect of sitagliptin on GLP-1 levels was examined in neonatal streptozotocin rats, a model of type 2 diabetes mellitus, a 4.9 ± 0.9-fold increase in basal and 3.6 ± 0.4-fold increase in oral glucose-stimulated plasma levels of active GLP-1 was observed (P < 0.001), in association with a 1.5 ± 0.1-fold increase in the total number of intestinal L cells (P < 0.01). The direct effects of sitagliptin on GLP-1 secretion and L cell signaling were therefore examined in murine GLUTag (mGLUTag) and human hNCI-H716 intestinal L cells in vitro. Sitagliptin (0.1-2 μM) increased total GLP-1 secretion by mGLUTag and hNCI-H716 cells (P < 0.01-0.001). However, MK0626 (1-50 μM), a structurally unrelated inhibitor of DPP-IV, did not affect GLP-1 secretion in either model. Treatment of mGLUTag cells with the GLP-1 receptor agonist, exendin-4, did not modulate GLP-1 release, indicating the absence of feedback effects of GLP-1 on the L cell. Sitagliptin increased cAMP levels (P < 0.01) and ERK1/2 phosphorylation (P < 0.05) in both mGLUTag and hNCI-H716 cells but did not alter either intracellular calcium or phospho-Akt levels. Pretreatment of mGLUTag cells with protein kinase A (H89 and protein kinase inhibitor) or MAPK kinase-ERK1/2 (PD98059 and U0126) inhibitors prevented sitagliptin-induced GLP-1 secretion (P < 0.05-0.01). These studies demonstrate, for the first time, that sitagliptin exerts direct, DPP-IV-independent effects on intestinal L cells, activating cAMP and ERK1/2 signaling and stimulating total GLP-1 secretion[3].

Mice: C57BL/6J mice that have been fasted overnight are challenged with an oral glucose load (2 g/kg) 45 minutes after the compound is administered. Tail bleed predose and successive time points following the glucose load are used to draw blood samples for glucose measurement. DPP-4 inhibitors or a vehicle are given 16 hours prior to the glucose challenge in order to assess how long the effect lasts on glucose tolerance.

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Effects of MK0431 on islet graft survival in diabetic NOD mice were determined with metabolic studies and micropositron emission tomography imaging, and its underlying molecular mechanisms were assessed.
Results: Treatment of NOD mice with MK0431 before and after islet transplantation resulted in prolongation of islet graft survival, whereas treatment after transplantation alone resulted in small beneficial effects compared with nontreated controls. Subsequent studies demonstrated that MK0431 pretreatment resulted in decreased insulitis in diabetic NOD mice and reduced in vitro migration of isolated splenic CD4+ T-cells. Furthermore, in vitro treatment of splenic CD4+ T-cells with DPP-IV resulted in increased migration and activation of protein kinase A (PKA) and Rac1.
Conclusions: Treatment with MK0431 therefore reduced the effect of autoimmunity on graft survival partially by decreasing the homing of CD4+ T-cells into pancreatic beta-cells through a pathway involving cAMP/PKA/Rac1 activation.[2]

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Effects of the DPP-IV inhibitor MK0431 (sitagliptin) on glycemic control and functional islet mass in a streptozotocin (STZ)-induced type 1 diabetes mouse model were determined with metabolic studies and microPET imaging.
Results: The type 1 diabetes mouse model exhibited elevated plasma DPP-IV levels that were substantially inhibited in mice on an MK0431 diet. Residual beta-cell mass was extremely low in STZ-induced diabetic mice, and although active GLP-1 levels were increased by the MK0431 diet, there were no significant effects on glycemic control. After islet transplantation, mice fed normal diet rapidly lost their ability to regulate blood glucose, reflecting the suboptimal islet transplant. By contrast, the MK0431 group fully regulated blood glucose throughout the study, and PET imaging demonstrated a profound protective effect of MK0431 on islet graft size.
Conclusions: Treatment with a DPP-IV inhibitor can prolong islet graft retention in an animal model of type 1 diabetes.[4]

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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.[5]

Absorption, Distribution and Excretion
Sitagliptin is 87% orally bioavailable and taking it with or without food does not affect its pharmacokinetics. Sitagliptin reaches maximum plasma concentration in 2 hours.
Approximately 79% of sitagliptin is excreted in the urine as the unchanged parent compound. 87% of the dose is eliminated in the urine and 13% in the feces.
198L.
350mL/min.
Sitagliptin is secreted in the milk of lactating rats at a milk to plasma ratio of 4:1. It is not known whether sitagliptin is excreted in human milk.
Placental transfer of sitagliptin administered to pregnant rats was approximately 45% at 2 hours and 80% at 24 hours postdose. Placental transfer of sitagliptin administered to pregnant rabbits was approximately 66% at 2 hours and 30% at 24 hours.
Approximately 79% of sitagliptin is excreted unchanged in the urine with metabolism being a minor pathway of elimination.
Elimination of sitagliptin occurs primarily via renal excretion and involves active tubular secretion. Sitagliptin is a substrate for human organic anion transporter-3 (hOAT-3), which may be involved in the renal elimination of sitagliptin. The clinical relevance of hOAT-3 in sitagliptin transport has not been established. Sitagliptin is also a substrate of p-glycoprotein, which may also be involved in mediating the renal elimination of sitagliptin. However, cyclosporine, a p-glycoprotein inhibitor, did not reduce the renal clearance of sitagliptin.
For more Absorption, Distribution and Excretion (Complete) data for SITAGLIPTIN (10 total), please visit the HSDB record page.

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Metabolism / Metabolites
Sitagliptin is mostly not metabolised, with 79% of the dose excreted in the urine as the unchanged parent compound. Minor metabolic pathways are mediated mainly by cytochrome p450(CYP)3A4 and to a lesser extent by CYP2C8. After 18 hours, 81% of the dose has remained unchanged, while 2% has been N-sulfated to the M1 metabolite, 6% has been oxidatively desaturated and cyclized to the M2 metabolite, <1% glucuronidated at an unknown site to the M3 metabolite, <1% has been carbamoylated and glucuronidated to the M4 metabolite, 6% has been oxidatively saturated and cyclized to the M5 metabolite, and 2% has been hydroxylated at an unknown site to the M6 metabolite. The M2 metabolite is the cis isomer while the M5 metabolite is the trans isomer of the same metabolite.
The metabolism and excretion of (14)C sitagliptin ... were investigated in humans after a single oral dose of 83 mg/193 muCi. Urine, feces, and plasma were collected at regular intervals for up to 7 days. The primary route of excretion of radioactivity was via the kidneys, with a mean value of 87% of the administered dose recovered in urine. Mean fecal excretion was 13% of the administered dose. Parent drug was the major radioactive component in plasma, urine, and feces, with only 16% of the dose excreted as metabolites (13% in urine and 3% in feces), indicating that sitagliptin was eliminated primarily by renal excretion. Approximately 74% of plasma AUC of total radioactivity was accounted for by parent drug. Six metabolites were detected at trace levels, each representing <1 to 7% of the radioactivity in plasma. These metabolites were the N-sulfate and N-carbamoyl glucuronic acid conjugates of parent drug, a mixture of hydroxylated derivatives, an ether glucuronide of a hydroxylated metabolite, and two metabolites formed by oxidative desaturation of the piperazine ring followed by cyclization. These metabolites were detected also in urine, at low levels. Metabolite profiles in feces were similar to those in urine and plasma, except that the glucuronides were not detected in feces. CYP3A4 was the major cytochrome P450 isozyme responsible for the limited oxidative metabolism of sitagliptin, with some minor contribution from CYP2C8.
Following a (14)C sitagliptin oral dose, approximately 16% of the radioactivity was excreted as metabolites of sitagliptin. Six metabolites were detected at trace levels and are not expected to contribute to the plasma DPP-4 inhibitory activity of sitagliptin. In vitro studies indicated that the primary enzyme responsible for the limited metabolism of sitagliptin was CYP3A4, with contribution from CYP2C8.

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Biological Half-Life
Approximately 12.4 hours. Other studies have reported a half life of approximately 11 hours.
Two double-blind, randomized, placebo-controlled, alternating-panel studies evaluated the safety, tolerability, pharmacokinetics, and pharmacodynamics of single oral doses of sitagliptin (1.5-600 mg) in healthy male volunteers. Sitagliptin was well absorbed (approximately 80% excreted unchanged in the urine) with an apparent terminal half-life ranging from 8 to 14 hours. ...
The apparent terminal half life following a 100 mg oral dose of sitagliptin was approximately 12.4 hours ... .

Toxicity Summary
IDENTIFICATION AND USE: Sitagliptin is a viscous liquid. It is a dipeptidyl peptidase-4 inhibitor and used to improve glycemic control in patients with type 2 diabetes. HUMAN EXPOSURE AND TOXICITY: Sitagliptin improves glycemic control and is generally well-tolerated in patients with type 2 diabetes. Sitagliptin use has been associated with an increased risk of heart failure -related hospitalizations among patients with type 2 diabetes with pre-existing heart failure. More recently a study has pointed to the possible use of sitagliptin in the treatment of some neurodegenerative conditions of the peripheral nervous system. Sitagliptin appears to be free from the adverse effects of weight gain and hypoglycemia that are associated some other treatments. ANIMAL STUDIES: Renal and liver toxicity were observed in rodents at systemic exposure to sitagliptin at values 58 times the human exposure level. Transient treatment-related physical signs, some of which suggest neural toxicity, such as open-mouth breathing, salivation, white foamy emesis, ataxia, trembling, decreased activity, and/or hunched posture were observed in dogs at exposure levels approximately 23 times the clinical exposure level. Carcinogenicity studies in mice did not show an increased incidence of tumors in any organ up to 500 mg/kg, but in rats there was an increased incidence of combined liver adenoma/carcinoma in males and females and of liver carcinoma in females at 500 mg/kg. Reproductive effects in rats and rabbits were only seen at doses greater than 250 mg/kg. Incisor teeth abnormalities were observed in rats at exposure levels 67 times the clinical exposure level. Sitagliptin was not mutagenic or clastogenic with or without metabolic activation in the Ames bacterial mutagenicity assay, a Chinese hamster ovary (CHO) chromosome aberration assay, an in vitro cytogenetics assay in CHO cells, an in vitro rat hepatocyte DNA alkaline elution assay, and an in vivo micronucleus assay.

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Hepatotoxicity
Liver injury due to sitagliptin is rare. In large clinical trials, serum enzyme elevations were no more common with sitagliptin therapy (0.5%) than with placebo (0.4%), and no instances of clinically apparent liver injury were reported. Since licensure, instances of serum enzyme elevations attributed to sitagliptin have been reported to the FDA and the sponsor. A single case report of clinically apparent liver injury has been published, but in a patient who also had hepatitis C. The pattern of serum enzyme elevations was hepatocellular and peak serum bilirubin was 9.4 mg/dL, with a rapid recovery upon stopping sitagliptin. Immunoallergic features and autoantibodies were absent.
Likelihood score: D (possible rare cause of clinically apparent liver injury).

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Effects During Pregnancy and Lactation
◉ Summary of Use during Lactation
No information is available on the clinical use of sitagliptin during breastfeeding. Sitagliptin has a shorter half-life than most other dipeptidyl-peptidase IV inhibitors, so it might be a better choice among drugs in this class for nursing mothers. Monitoring of the breastfed infant's blood glucose is advisable during maternal therapy with sitagliptin. However, an alternate drug may be preferred, especially while nursing a newborn or preterm infant.
◉ Effects in Breastfed Infants
Relevant published information was not found as of the revision date.
◉ Effects on Lactation and Breastmilk
Relevant published information was not found as of the revision date.

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Protein Binding
38%.

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Interactions
Concomitant administration of cyclosporine and sitagliptin may increase absorption and plasma concentrations of sitagliptin. However, this interaction is not considered clinically important.
Sitagliptin and metformin have a potential additive effect on active glucagon-like peptide (GLP-1) concentrations. Pharmacokinetic interactions are unlikely. The relevance of these effects to glycemic control in patients with type 2 diabetes mellitus is unclear.
There was a slight increase in the area under the curve (AUC, 11%) and mean peak drug concentration (Cmax, 18%) of digoxin with the co-administration of 100 mg sitagliptin for 10 days. Patients receiving digoxin should be monitored appropriately. No dosage adjustment of digoxin or Januvia is recommended.
When sitagliptin was used in combination with a sulfonylurea or insulin, the incidence of hypoglycemia was greater than that in patients receiving placebo with a sulfonylurea or insulin. In a long-term (52-week) clinical noninferiority study, rates of hypoglycemia with sitagliptin/metformin combination therapy were lower than those observed with glipizide/metformin combination therapy. However, in a 24-week clinical study, rates of hypoglycemia in patients receiving sitagliptin and glimepiride with or without metformin were greater than those in patients receiving glimepiride and metformin. Patients receiving sitagliptin may require a lower dosage of a concomitant insulin secretagogue (e.g., sulfonylurea) or insulin to reduce the risk of hypoglycemia.

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Non-Human Toxicity Values
LD50 Mouse oral 4000 mg/kg
LD50 Rat oral >3000 mg/kg

[1]. (R)-8-(3-amino-piperidin-1-yl)-7-but-2-ynyl-3-methyl-1-(4-methyl-quinazolin-2-ylm ethyl)-3,7-dihydro-purine-2,6-dione (BI 1356), a novel xanthine-based dipeptidyl peptidase 4 inhibitor, has a superior potency and longer duration of acti.

[2]. Dipeptidyl peptidase IV inhibition with MK0431 improves islet graft survival in diabetic NOD mice partially via T-cell modulation. Diabetes, 2009. 58(3): p. 641-51.

[3]. Novel biological action of the dipeptidylpeptidase-IV inhibitor, sitagliptin, as a GLP-1 secretagogue. Endocrinology, 2012. 153(2): p. 564-73.

[4]. Inhibition of dipeptidyl peptidase IV with sitagliptin (MK0431) prolongs islet graft survival in streptozotocin-induced diabetic mice. Diabetes, 2008. 57(5): p. 1331-9.

[5]. Disposition of the dipeptidyl peptidase 4 inhibitor sitagliptin in rats and dogs. Drug Metab Dispos, 2007. 35(4): p. 525-32.

Therapeutic Uses
Hypoglycemic Agents
Januvia is indicated as an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus. /Included in US product label/
Januvia should not be used in patients with type 1 diabetes or for the treatment of diabetic ketoacidosis, as it would not be effective in these settings.
Type 2 diabetes mellitus is a common chronic disease that causes significant morbidity and mortality worldwide. The primary goal of treatment is to target glycemic control by maintaining the glycosylated hemoglobin level near 6-7% without predisposing patients to hypoglycemia. Diabetes results from a combination of increased hepatic glucose production, decreased insulin secretion from beta cells, and insulin resistance in the peripheral tissues. Currently available antidiabetic agents work by different mechanisms to lower blood glucose levels. Unfortunately, each of them has its tolerability and safety concerns that limit its use and dose titration. Sitagliptin is the first antidiabetic agent from the class of dipeptidyl peptidase-4 enzyme inhibitors. It increases the amount of circulating incretins, which stimulate insulin secretion and inhibit glucose production. Sitagliptin was approved by the US Food and Drug Administration (FDA) for use with diet and exercise to improve glycemic control in adult patients with type 2 diabetes. It can be used alone or in combination with metformin or a thiazolidinedione (pioglitazone or rosiglitazone) when treatment with either drug alone provides inadequate glucose control. The usual adult dose is 100 mg once daily. A dose of 25-50 mg once daily is recommended for patients with moderate-to-severe renal impairment. In randomized, placebo-controlled trials that lasted for up to 6 months, sitagliptin lowered glycosylated hemoglobin levels by 0.5-0.8%. In a 52-week clinical trial, sitagliptin was shown to be noninferior to glipizide as an add-on agent in patients inadequately controlled on metformin alone. Sitagliptin was well tolerated with the most common side effects being gastrointestinal complaints (up to 16%), including abdominal pain, nausea and diarrhea; hypoglycemia and body weight gain occurred at similar rates compared with placebo. Overall, sitagliptin provides a treatment option for patients with type 2 diabetes as a monotherapy, or as an adjunct to metformin or a thiazolidinedione when patients achieve inadequate glycemic control while on either of the agents. It is also an alternative therapy for those patients who have contraindications or intolerability to other antidiabetic agents.
For more Therapeutic Uses (Complete) data for SITAGLIPTIN (6 total), please visit the HSDB record page.

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Drug Warnings
/BOXED WARNING/ WARNING: LACTIC ACIDOSIS. Lactic acidosis is a rare, but serious, complication that can occur due to metformin accumulation. The risk increases with conditions such as sepsis, dehydration, excess alcohol intake, hepatic impairment, renal impairment, and acute congestive heart failure. The onset of lactic acidosis is often subtle, accompanied only by nonspecific symptoms such as malaise, myalgias, respiratory distress, increasing somnolence, and nonspecific abdominal distress. Laboratory abnormalities include low pH, increased anion gap, and elevated blood lactate. If acidosis is suspected, Janumet should be discontinued and the patient hospitalized immediately. /Sitagliptin and metformin hydrochloride combination product/
FDA is evaluating unpublished new findings by a group of academic researchers that suggest an increased risk of pancreatitis and pre-cancerous cellular changes called pancreatic duct metaplasia in patients with type 2 diabetes treated with a class of drugs called incretin mimetics. These findings were based on examination of a small number of pancreatic tissue specimens taken from patients after they died from unspecified causes. FDA has asked the researchers to provide the methodology used to collect and study these specimens and to provide the tissue samples so the Agency can further investigate potential pancreatic toxicity associated with the incretin mimetics. Drugs in the incretin mimetic class include exenatide (Byetta, Bydureon), liraglutide (Victoza), sitagliptin (Januvia, Janumet, Janumet XR, Juvisync), saxagliptin (Onglyza, Kombiglyze XR), alogliptin (Nesina, Kazano, Oseni), and linagliptin (Tradjenta, Jentadueto). These drugs work by mimicking the incretin hormones that the body usually produces naturally to stimulate the release of insulin in response to a meal. They are used along with diet and exercise to lower blood sugar in adults with type 2 diabetes. FDA has not reached any new conclusions about safety risks with incretin mimetic drugs. This early communication is intended only to inform the public and health care professionals that the Agency intends to obtain and evaluate this new information. ... FDA will communicate its final conclusions and recommendations when its review is complete or when the Agency has additional information to report. The Warnings and Precautions section of drug labels and patient Medication Guides for incretin mimetics contain warnings about the risk of acute pancreatitis. FDA has not previously communicated about the potential risk of pre-cancerous findings of the pancreas with incretin mimetics. FDA has not concluded these drugs may cause or contribute to the development of pancreatic cancer. At this time, patients should continue to take their medicine as directed until they talk to their health care professional, and health care professionals should continue to follow the prescribing recommendations in the drug labels. ...
Acute pancreatitis, including fatal and nonfatal hemorrhagic or necrotizing pancreatitis, has been reported during postmarketing experience in patients receiving sitagliptin or sitagliptin/metformin. The most common manifestations associated with pancreatitis were abdominal pain, nausea, and vomiting. Hospitalization was required in 66% of 88 reported cases, including 2 cases of hemorrhagic or necrotizing pancreatitis that necessitated prolonged hospitalization and intensive-care unit (ICU) care. Pancreatitis occurred within 30 days of initiation of sitagliptin or sitagliptin/metformin therapy in 21% of cases; discontinuance of the drug led to resolution of pancreatitis in 53% of patients. At least one other risk factor (e.g., obesity, high cholesterol and/or triglyceride concentrations) was noted in 51% of cases.
Renal function should be assessed prior to initiation of sitagliptin and periodically thereafter. Worsening of renal function, including acute renal failure that sometimes required dialysis, has been reported in some patients during postmarketing experience. A subset of these patients had renal insufficiency, some of whom were prescribed inappropriate dosages of sitagliptin. A return to baseline levels of renal insufficiency has been observed with supportive treatment and discontinuance of potentially causative agents. Cautious reinitiation of sitagliptin can be considered if another etiology is deemed likely to have precipitated the acute worsening of renal function. The manufacturer states that sitagliptin has not been found to be nephrotoxic in clinical trials or in preclinical studies at clinically relevant dosages.
For more Drug Warnings (Complete) data for SITAGLIPTIN (17 total), please visit the HSDB record page.

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Pharmacodynamics
Sitagliptin inhibits DPP-4 which leads to increased levels of glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide(GIP), decreased levels of glucagon, and a stronger insulin response to glucose.

C16H15F6N5O

407.32

407.118

C, 47.18; H, 3.71; F, 27.99; N, 17.19; O, 3.93

486460-32-6

Sitagliptin phosphate;654671-78-0;Sitagliptin phosphate monohydrate;654671-77-9;(S)-Sitagliptin phosphate;823817-58-9;(Rac)-Sitagliptin;823817-56-7;Sitagliptin-d4 hydrochloride

4369359

White to off-white solid powder

1.6±0.1 g/cm3

529.9±60.0 °C at 760 mmHg

274.3±32.9 °C

0.0±1.4 mmHg at 25°C

1.590

1.3

1

10

4

28

566

1

FC(C1=NN=C2C([H])([H])N(C(C([H])([H])[C@@]([H])(C([H])([H])C3=C([H])C(=C(C([H])=C3F)F)F)N([H])[H])=O)C([H])([H])C([H])([H])N21)(F)F

MFFMDFFZMYYVKS-SECBINFHSA-N

InChI=1S/C16H15F6N5O/c17-10-6-12(19)11(18)4-8(10)3-9(23)5-14(28)26-1-2-27-13(7-26)24-25-15(27)16(20,21)22/h4,6,9H,1-3,5,7,23H2/t9-/m1/s1

(3R)-3-amino-1-[3-(trifluoromethyl)-6,8-dihydro-5H-[1,2,4]triazolo[4,3-a]pyrazin-7-yl]-4-(2,4,5-trifluorophenyl)butan-1-one

EC 690-730-1; HSDB 7516; HSDB7516; HSDB-7516; Januvia; LEZ 763; LEZ-763; LEZ763; Tesavel; Xelevia; (R)-3-AMINO-1-(3-(TRIFLUOROMETHYL)-5,6-DIHYDRO-[1,2,4]TRIAZOLO[4,3-A]PYRAZIN-7(8H)-YL)-4-(2,4,5-TRIFLUOROPHENYL)BUTAN-1-ONE; sitagliptina; MK-0431; MK0431; MK 0431; MK-431; MK431; MK 431; Sitagliptin Phosphate; Sitagliptin Phosphate Monohydrate; trade name: Januvia Xelevia Janumet

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Solubility in Formulation 1: ≥ 2.5 mg/mL (6.14 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (6.14 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 3: 2.5 mg/mL (6.14 mM) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution; Need heat to 60°C.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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 (Please use freshly prepared in vivo formulations for optimal results.)