Selective Dipeptidyl peptidase-IV Inhibitor Research Articles

Design of some Apigenin derivatives as selective DPP-IV Inhibitors by Pharmacophore Modelling and its Validation through Molecular Dynamics Simulation

One of the most common forms of diabetes, type-2 diabetes mellitus is a chronic metabolic condition brought on by problems with insulin production or insulin resistance. By modifying blood glucose homeostasis, dipeptidyl peptidase-IV (DPP-IV) inhibition has the potential to treat type 2 diabetes. The quick development of computational drug design provided a fantastic opportunity to both discover and forecast the effectiveness of potential DPP-IV inhibitors. The current investigation supports and verifies the identification of new Apigenin derivatives as selective DPP-IV inhibitors. Schrodinger software was used to perform virtual screening (VS) of created compounds against DPP-IV, and the most promising hits were chosen. Out of 110 substances, 56 new apigenin derivatives were chosen for additional docking investigations using Glide based on their selectivity threshold followed by validation by pose selection method which is found to be below 2 Ǻ based on their superimposion with co-crystallized lgand. The DPP-IV protein was used as the target of molecular dynamic (MD) simulation studies to evaluate the correct binding mechanisms and stability of their complexes with enzyme. Structural chemistry was utilised to guide and considerably speed up the drug discovery process during the back-up development stages. It was also used to analyse in-silico suggestions and screening results, as well as to come up with fresh ideas. The study thus demonstrates the possibility of apigenin derivatives as highly specific DPP-IV inhibitors.

Preparation and optimization of tetraethyl orthosilicate cross-linked chitosan-guar gum-poly(vinyl alcohol) composites reinforced with montmorillonite for sustained release of sitagliptin

Development of efficient drug carriers has become an integral part of advanced drug delivery systems. This work aims at developing composites by adopting an economically viable method for sustained release of anti-diabetic drug sitagliptin — a potent and selective dipeptidyl peptidase-IV inhibitor. To combat the harsh environment of gastrointestinal tract, the composite (F13) was prepared using biodegradable polymers namely chitosan, guar gum and poly(vinyl alcohol) with montmorillonite clay as nano-filler and tetraethyl orthosilicate as the cross linker. The composites were characterized using FT-IR, XRD, DSC and SEM techniques. Physical properties such as thickness, swelling capacity, folding endurance and water solubility were studied. In vitro analysis of composites (F17, F19 and F20) in simulated gastric medium showed <14 % cumulative release in 2 h while a sustained release was observed in simulated intestinal medium. Drug release kinetics was investigated using five mathematical models namely zero order, first order, Higuchi, Hixon-Crowell and Korsemeyer-Peppas wherein the latter was the best fit model (R2, 0.969). Antimicrobial studies of drug free composite (F13) revealed good activity against bacteria as well as fungi. The results implied that the composites were pH sensitive and could serve as a potential choice for sustained release of drugs.

Activity and selectivity cliffs for DPP-IV inhibitors: Lessons we can learn from SAR studies and their application to virtual screening.

The inhibition of dipeptidyl peptidase-IV (DPP-IV) has emerged over the last decade as one of the most effective treatments for type 2 diabetes mellitus, and consequently (a) 11 DPP-IV inhibitors have been on the market since 2006 (three in 2015), and (b) 74 noncovalent complexes involving human DPP-IV and drug-like inhibitors are available at the Protein Data Bank (PDB). The present review aims to (a) explain the most important activity cliffs for DPP-IV noncovalent inhibition according to the binding site structure of DPP-IV, (b) explain the most important selectivity cliffs for DPP-IV noncovalent inhibition in comparison with other related enzymes (i.e., DPP8 and DPP9), and (c) use the information deriving from this activity/selectivity cliff analysis to suggest how virtual screening protocols might be improved to favor the early identification of potent and selective DPP-IV inhibitors in molecular databases (because they have not succeeded in identifying selective DPP-IV inhibitors with IC50 ≤ 100nM). All these goals are achieved with the help of available homology models for DPP8 and DPP9 and an analysis of the structure-activity studies used to develop the noncovalent inhibitors that form part of some of the complexes with human DPP-IV available at the PDB.

Ephedrine as a lead compound for the development of new DPP-IV inhibitors.

Extracts from Ephedra species have been reported to be effective as antidiabetics. A previous in silico study predicted that ephedrine and five ephedrine derivatives could contribute to the described antidiabetic effect of Ephedra extracts by inhibiting dipeptidyl peptidase IV (DPP-IV). Finding selective DPP-IV inhibitors is a current therapeutic strategy for Type 2 diabetes mellitus management. Therefore, the main aim of this work is to experimentally determine whether these alkaloids are DPP-IV inhibitors. Materials& methods: The DPP-IV inhibition ofEphedra's alkaloids was determined via a competitive-binding assay. Then, computational analyses were used in order to find out the protein-ligand interactions and to perform a lead optimization. Our results show that all six molecules are DPP-IV inhibitors, with IC50 ranging from 124μM for ephedrine to 28 mM for N-methylpseudoephedrine. Further computational analysis shows how Ephedra's alkaloids could be used as promising lead molecules for designing more potent and selective DPP-IV inhibitors.

Novel hydrazine derivatives as selective DPP-IV inhibitors: findings from virtual screening and validation through molecular dynamics simulations

The present study demonstrates and validates the discovery of two novel hydrazine derivatives as selective dipeptidyl peptidase-IV (DPP-IV) inhibitors. Virtual screening (VS) of publicly available databases was performed using virtual screening workflow (VSW) of Schrödinger software against DPP-IV and the most promising hits were selected. Selectivity was further assessed by docking the hits against homology modeled structures of DPP8 and DPP9. Two novel hydrazine derivatives were selected for further studies based on their selectivity threshold. To assess their correct binding modes and stability of their complexes with enzyme, molecular dynamic (MD) simulation studies were performed against the DPP-IV protein and the results revealed that they had a better binding affinity towards DPP-IV as compared to DPP 8 and DPP 9. The binding poses were further validated by docking these ligands with different softwares (Glide and Gold). The proposed binding modes of hydrazines were found to be similar to sitagliptine and alogliptine. Thus, the study reveals the potential of hydrazine derivatives as highly selective DPP-IV inhibitors.

Soluble CD26/Dipeptidyl Peptidase IV Enhances the Transcription of IL-6 and TNF-α in THP-1 Cells and Monocytes

CD26 is a 110-kDa multifunctional molecule having dipeptidyl peptidase IV (DPPIV) enzyme activity and is present on the surface of human T cells. Soluble CD26 (sCD26) exists in human blood and enhances the proliferation of peripheral T lymphocytes induced by tetanus toxoid (TT). The mechanisms by which CD26 enhances the activation of T cells and monocytes remain to be fully elucidated. In this study, we compared the stimulation of THP-1 cells and isolated human monocytes with a combination of recombinant sCD26 and lipopolysaccharide (LPS) and the stimulation of these cells with LPS alone. We found that addition of sCD26 increased TNF-α and IL-6 mRNA and protein expression and enhanced ERK1/2 levels in the cytosol as well as c-Fos, NF-κB p50, NF-κB p65, and CUX1 levels in the nuclei of these cells. On the other hand, the selective DPPIV inhibitor sitagliptin inhibited the increase in TNF-α mRNA and protein expression as well as the increase in ERK, c-Fos, NF-κB p50, NF-κB p65, and CUX1 levels. However, it did not inhibit the increase in IL-6 mRNA and protein expression. We then demonstrated that sCD26 enhanced binding of transcription factors to the TNF- and IL-6 promoters and used reporter assays to demonstrate that transcription factor binding enhanced promoter activity. Once again, we observed differential activities at the TNF- and IL-6 promoters. Finally, we demonstrated that CUX-1 overexpression enhanced TNF- production on sCD26/LPS stimulation, while CUX-1 depletion had no effect. Neither CUX-1 overexpression nor CUX-1 depletion had an effect on IL-6 stimulation. These results are discussed in the context of a model that describes the mechanisms by which stimulation of monocytic cells by sCD26 and LPS leads to elevation of TNF- and IL-6 expression. CUX-1 is identified as a new transcription factor that differently regulates the activities of the TNF- and IL-6 promoters.

Safety, Tolerability, Pharmacokinetics and Pharmacodynamics of E3024, a Novel and Selective Dipeptidyl Peptidase-IV Inhibitor, in Healthy Japanese Male Subjects: Rash Development in Men and Its Possible Mechanism

E3024 (3-but-2-ynyl-5-methyl-2-piperazin-1-yl-3,5-dihydro-4H-imidazo[4,5-d]pyridazin-4-one tosylate) is a dipeptidyl peptidase-IV (DPP-IV) inhibitor that was expected to be an antidiabetic agent. Its safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) were investigated in a randomized, double-blind, placebo-controlled, ascending single-dose study in 48 healthy Japanese male subjects. Fasted subjects were orally administered E3024 (5, 10, 20, 40, or 80 mg) or placebo. E3024 was rapidly absorbed, with tmax values ranging between 0.33 and 3 h after dosing. The mean t1/2 ranged from 5.34 to 11.68 h. AUC0-inf and Cmax increased dose-proportionately. PK-PD relationship of E3024 was evaluated by using an Imax model, indicating that plasma E3024 concentrations and inhibitory effects of plasma DPP-IV activity were well correlated. The IC50 value was calculated as 33.7 ng/mL, which was consistent with in vitro data. Thus, E3024 showed a good PK profile and inhibited DPP-IV dose-dependently. Of 30 subjects administered E3024, 12 (40%) experienced adverse events (AEs). Dose escalation to 160 mg was abandoned owing to undesired subjective/objective findings in 4 of 6 subjects receiving 40 mg and 5 of 6 subjects receiving 80 mg. The most prominent AE was rash, but there were no serious AEs or deaths. The maximum tolerated dose was considered to be 20 mg. We hypothesized that histamine was a cause of the rash induction, and examined blood histamine levels of normal Fischer rats treated with E3024. Blood histamine levels were increased significantly by E3024 at 500 mg/kg (p Ws/Ws rats treated with E3024 at 500 mg/kg. In in vitro assays, E3024 induced histamine release from normal rat peritoneal mast cells in a concentration-dependent manner, but not from basophils. The structure-activity relationship study suggested that a piperazine group N-linked to the 2-position of the 5,6-membered fused heterocyclic rings was a key structural element for triggering histamine release.

Biological evaluation of RBx-0128, a potent and selective dipeptidyl peptidase-IV inhibitor in type 2 diabetes genetic model

Aim:Dipeptidyl peptidase IV (DPP-IV) inhibition to modulate the incretin effect is a proven strategy to treat type 2 diabetes mellitus. The present study describes the pharmacological profile of a novel DPP-IV inhibitor RBx-0128, as an antidiabetic agent.Material and Methods:DPP-IV assay was carried out to evaluate in vitro potency of RBx-0128 using human, mouse, and rat plasma as an enzyme source. Selectivity was assessed with various serine proteases. In vivo efficacy was assessed in ob/ob mice. The pharmacokinetic (PK) profile was performed in Wistar rats.Results:RBx-0128 inhibited human, mouse, and rat plasma DPP-IV activity with IC50 values of 10.6, 18.1, and 56.0 nM respectively, selective over various serine proteases (900–9000-fold). The inhibition was reversible and competitive in nature. In ob/ob mice, RBx-0128 significantly (P < 0.05) inhibited plasma DPP-IV and stimulated GLP-1 and insulin at 10 mg/kg. In the oral glucose tolerance test (OGTT), glucose lowering effect was better than sitagliptin (23 vs. 17%) at 10 mg/kg. The effect was sustained till 8 hours (30-35%) at 10 mg/kg with favorable PK profile (plasma clearance: 39.3 ml/min/kg; Cmax 790 ng/ml; t1/2 1.6 hours; tmax 4.8 hours, Vss 3.24 l/kg and Foral 55%) in Wistar rats.Conclusions:The present study showed that RBx-0128 is a novel, DPP-IV inhibitor with an antihyperglycemic effect. It can be a promising candidate for the treatment of type 2 diabetes mellitus.

Non-competitive and selective dipeptidyl peptidase IV inhibitors with phenethylphenylphthalimide skeleton derived from thalidomide-related α-glucosidase inhibitors and liver X receptor antagonists

Novel dipeptidyl peptidase IV (DPP-IV) inhibitors with a phenethylphenylphthalimide skeleton were prepared based on α-glucosidase inhibitors and liver X receptor (LXR) antagonists derived from thalidomide. Representative compounds showed non-competitive inhibition of DPP-IV and 28a exhibited 10-fold selectivity for DPP-IV over DPP-8. Compound 28a is the first non-competitive, selective DPP-IV inhibitor.

Crystal Structures of Human Dipeptidyl Peptidase IV in its Apo and Diprotin B-complexed Forms

Dipeptidyl peptidase IV (DPPIV), which belongs to the prolyl oligopeptidase family of serine proteases, is known to have a variety of regulatory biological functions and has been shown to be implicated in type 2 diabetes. It is therefore important to develop selective human DPPIV (hDPPIV) inhibitors. In this study, we determined the crystal structure of apo hDPPIV at 1.9 A resolution. Our high-resolution crystal structure of apo hDPPIV revealed the presence of sodium ion and glycerol molecules at the active site. In order to elucidate the hDPPIV binding mode and substrate specificity, we determined the crystal structure of hDPPIV-diprotin B (Val-Pro-Leu) complex at 2.1 A resolution, and clarified the difference in binding mode between diprotin B and diprotin A (Ile-Pro-Ile) into the active site of hDPPIV. Comparison between our crystal structures and the reported apo hDPPIV structures revealed that positively charged functional groups and conserved water molecules contributed to the interaction of ligands with hDPPIV. These results are useful for the design of potent hDPPIV inhibitors.

Incretins and other peptides in the treatment of diabetes

Glucagon-like peptide-1 (7-36) amide (GLP-1) is a gut hormone, released postprandially,which stimulates insulin secretion and insulin gene expression as well as pancreatic B-cell growth. Together with glucose-dependent insulinotropic polypeptide (GIP), it is responsible for the incretin effect which is the augmentation of insulin secretion following oral administration of glucose. Patients with Type 2 diabetes have greatly impaired or absent incretin-mediated insulin secretion which is mainly as a result of decreased secretion of GLP-1. However,the insulinotropic action of GLP-1 is preserved in patients with Type 2 diabetes,and this has encouraged attempts to treat Type 2 diabetic patients with GLP-1.GLP-1 also possesses a number of potential advantages over existing agents for the treatment of Type 2 diabetes. In addition to stimulating insulin secretion and promoting pancreatic B-cell mass, GLP-1 suppresses glucagon secretion,delays gastric emptying and inhibits food intake. Continuous intravenous and subcutaneous administration significantly improves glycaemic control and causes reductions in both HbA1c and body weight. However, GLP-1 is metabolized extremely rapidly in the circulation by the enzyme dipeptidyl peptidase IV(DPP-IV). This is the probable explanation for the short-lived effect of single doses of native GLP-1, making it an unlikely glucose-lowering agent. The DPP-IV resistant analogue, exenatide, has Food and Drug Administration (FDA) approval for the treatment of Type 2 diabetes and selective DPP-IV inhibitors are underdevelopment. Both approaches have demonstrated remarkable efficacy in animal models and human clinical studies. Both are well tolerated and appear to have advantages over current therapies for Type 2 diabetes, particularly in terms of the effects on pancreatic B-cell restoration and potential weight loss.

E3024, 3-but-2-ynyl-5-methyl-2-piperazin-1-yl-3,5-dihydro-4 H-imidazo[4,5- d]pyridazin-4-one tosylate, is a novel, selective and competitive dipeptidyl peptidase-IV inhibitor

Dipeptidyl peptidase IV (DPP-IV) inhibitors are expected to become a useful new class of anti-diabetic agent. The aim of the present study is to characterize the in vitro and in vivo profile of E3024, 3-but-2-ynyl-5-methyl-2-piperazin-1-yl-3,5-dihydro-4 H-imidazo[4,5- d]pyridazin-4-one tosylate, which is a novel imidazopyridazinone-derived DPP-IV inhibitor. E3024 inhibited recombinant human and mouse DPP-IV with IC 50 values of approximately 100 nM. E3024 inhibited DPP-IV in human, mouse, rat and canine plasma with IC 50 values of 140 to 400 nM. In contrast, E3024 did not inhibit DPP-8 or DPP-9 activity. Kinetic analysis indicated that E3024 is a competitive DPP-IV inhibitor. In Zucker fa/fa rats, E3024 (1 mg/kg) reduced glucose excursion after glucose load, with increases in plasma insulin and active glucagon-like peptide-1 levels. In fasted rats, this compound did not cause hypoglycemia. In a rat 4-week toxicological study, no notable changes were found at doses up to 750 mg/kg. The present preclinical studies indicate that E3024 is a novel selective DPP-IV inhibitor with anti-diabetic effects and a good safety profile.

PIII-60Effect of renal insufficiency on the pharmacokinetics of MK-0431 (sitagliptin), a selective dipeptidyl-peptidase-IV (DPP-IV) inhibitor

BACKGROUND/AIMS This study was conducted to evaluate the influence of renal insufficiency (RI) on the pharmacokinetics (PK) of sitagliptin (SIT), a selective DPP-IV inhibitor in Phase III development for the treatment of type 2 diabetes. METHODS 6 patients/subjects in each of the following groups: mild RI (creatinine clearance (CrCl) = 50 to 80 mL/min), moderate RI (CrCl = 30 to 50 mL/min), severe RI (CrCl < 30 mL/min) and healthy subjects (CrCl > 80 mL/min). Each group received a single oral 50-mg dose of SIT. End-stage renal disease (ESRD) patients received 2 single oral 50-mg doses (hemodialysis 4-hr or 48-hr postdose). SIT PK in RI patients was compared to concurrent and historical control subjects. Less than 2-fold increases in AUC0-∞were not considered clinically meaningful changes. RESULTS SIT AUC0-∞ was approximately inversely related to CrCl. Renal clearance (ClR) was approximately proportional to CrCl. AUC0-∞ increased less than 2-fold for CrCl > 50 mL/min. AUC0-∞ was 1.6, 2.3, 3.8 and 4.5-fold higher in mild RI, moderate RI, severe RI and ESRD patients, respectively, compared to healthy subjects. Cmax was 1.4, 1.4, 1.8 and 1.4 higher in mild moderate and severe RI and ESRD, respectively. Dialysis removed ∼13.5% of the dose. SIT was well tolerated in all groups. CONCLUSIONS Mild RI patients do not require dose-adjustment. To obtain an exposure of SIT similar to patients without renal insufficiency, moderate RI, and severe RI and ESRD patients should receive ½ and ¼ of the usual SIT dose, respectively. Clinical Pharmacology & Therapeutics (2005) 79, P75–P75; doi: 10.1016/j.clpt.2005.12.268

PII-46Sitagliptin (MK-0431), a selective dipeptidyl-peptidase-IV (DPP-IV) inhibitor, does not affect the pharmacokinetics of simvastatin in humans

BACKGROUND/AIMS MK-0431 (sitagliptin) is a selective DPP-IV inhibitor in Phase III development for the treatment of type 2 diabetes. Since sitagliptin is expected to be commonly co-administered with statins, the effect of sitagliptin on the pharmacokinetics (PK) of simvastatin, a CYP3A4 substrate, was evaluated. METHODS Twelve healthy subjects were randomized to 2 treatment periods: (A) a single oral dose of simvastatin 20 mg and (B) daily oral doses of 200 mg sitagliptin on Days 1 through 5 and a single oral dose of simvastatin 20 mg on Day 5. Plasma was collected for 24 hours following each simvasatin dose to determine the PK of active HMG-CoA reductase inhibitors (represents all active inhibitors in plasma; primary analyte), total HMG-CoA reductase inhibitors, simvastatin, and simvastatin acid. RESULTS Active inhibitor geometric mean ratio (simvastatin+sitagliptin/simvastatin) and the 90% CI for AUC0-last and Cmax were 1.06 (0.88, 1.26) and 0.94 (0.66, 1.34), respectively, with no meaningful difference in Tmax between treatments (median 1.8 hours for both treatments). Additionally, there were no clinically or statistically meaningful differences in AUC0-last, Cmax or Tmax between treatments for the other three analytes evaluated (total inhibitors, simvastatin and simvastatin acid). Sitagliptin and simvastatin were well tolerated. CONCLUSIONS Multiple oral doses of sitagliptin do not meaningfully alter the pharmacokinetics of simvastatin. Clinical Pharmacology & Therapeutics (2005) 79, P48–P48; doi: 10.1016/j.clpt.2005.12.171

Pharmacokinetic and pharmacodynamic properties of multiple oral doses of sitagliptin, a dipeptidyl peptidase-IV inhibitor: A double-blind, randomized, placebo-controlled study in healthy male volunteers

Background: Dipeptidyl peptidase-IV (DPP-IV) inhibitorsrepresent a new class of oral antihyperglycemic agents. Sitagliptin is an orally active and selective DPP-IV inhibitor currently in Phase III development for the treatment of type 2 diabetes mellitus. Objective: The aim of this study was to assess the pharmacokinetic and pharmacodynamic (PK/PD) properties and tolerability of multiple oral once-daily or twice-daily doses of sitagliptin. Methods: This double-blind, randomized, placebo-controlled,incremental oral-dose study was conducted at SGS Biopharma, Antwerp, Belgium. Healthy, nonsmoking male volunteers aged 18 to 45 years with a creatinine clearance rate of >80 mL/min and normoglycemia and weighing within 15% of their ideal height/weight range were randomly assigned to 1 of 8 treatment groups: sitagliptin 25, 50, 100, 200, or 400 mg or placebo, QD for 10 days; a single dose of sitagliptin 800 mg administered on day 1 followed by 600 mg QD on days 3 to 10; or sitagliptin 300 mg BID for 10 days. For analysis of PK properties, plasma and urine samples were obtained before study drug administration on day 1 and at 0.5, 1, 2, 4, 6, 8, 10, 12, and 16 hours after study drug administration on day 1; before study drug administration on days 2 to 9; and every 24 hours for 96 hours after the last dose on day 10, and analyzed for sitagliptin concentrations. Assays were used to measure inhibition of plasma DPP-IV activity and plasma concentrations of active and total glucagon-like peptide-1 (GLP-1), glucose, and glucagon, and serum concentrations of insulin, C-peptide, insulin-like growth factor-1, and insulin like growth factor binding protein-3. Tolerability was assessed throughout the study using physical examination, including vital sign measurements; 12-lead electrocardiography; and laboratory analysis, including hematology, biochemistry (hepatic aminotransferase and creatine phosphokinase), and urinalysis. Results: Seventy subjects were enrolled (mean age, 32.9 years [range, 18–45 years]; mean weight, 79.7 kg [range, 63.4–97.7 kg]; 8 patients per sitagliptin study group and 14 patients in the control group). In the sitagliptin groups, the plasma concentration-time profiles and principal PK parameters (T max, C max, and t ½) were statistically similar at days 1 (single dose) and 10 (steady state). In the groups receiving sitagliptin QD doses, accumulation of sitagliptin was modest (AUC accumulation ratio [day 10/day 1] range, 1.05–1.29), and the apparent terminal elimination t ½ was 11.8 to 14.4 hours. At steady state in the sitagliptin QD groups, the mean proportion of drug excreted unchanged in the urine was ∼70.6%. Dose-dependent inhibition of plasma DPP-IV activity was apparent, and the pattern of inhibition at steady state (day 10) was statistically similar to that observed on day 1. Day-10 weighted mean inhibition of plasma DPP-IV activity over 24 hours was ≥ 80% for doses of ≥ 50 mg QD. After a standard meal, active GLP-1 concentrations were significantly increased in the sitagliptin groups by ∼2-fold compared with that in the control group, a finding consistent with near-maximal acute glucose lowering in preclinical studies. Across doses, no apparent adverse effects, including hypoglycemia, were found or reported. Conclusions: The results from this study in a select population of healthy male volunteers suggest that multiple oral doses of sitagliptin inhibited plasma DPP-IV activity and affected active GLP-1 concentrations in a dose-dependent manner, without producing hypoglycemia. Multiple dosing of sitagliptin exhibited a PK/PD profile consistent with that of a QD regimen and was well tolerated.

2-[3-[2-[(2S)-2-Cyano-1-pyrrolidinyl]-2-oxoethylamino]-3-methyl-1-oxobutyl]- 1,2,3,4-tetrahydroisoquinoline: A Potent, Selective, and Orally Bioavailable Dipeptide-Derived Inhibitor of Dipeptidyl Peptidase IV

Dipeptidyl peptidase IV (DPP-IV) inhibitors are expected to become a new type of antidiabetic drugs. Most known DPP-IV inhibitors often resemble the dipeptide cleavage products, with a proline mimic at the P1 site. As off-target inhibitions of DPP8 and/or DPP9 have shown profound toxicities in the in vivo studies, it is important to develop selective DPP-IV inhibitors for clinical usage. To achieve this, a new class of 2-[3-[[2-[(2S)-2-cyano-1-pyrrolidinyl]-2-oxoethyl]amino]-1-oxopropyl]-based DPP-IV inhibitors was synthesized. SAR studies resulted in a number of DPP-IV inhibitors, having IC(50) values of <50 nM with excellent selectivity over both DPP8 (IC(50) > 100 microM) and DPP-II (IC(50) > 30 microM). Compound 21a suppressed the blood glucose elevation after an oral glucose challenge in Wistar rats and also inhibited plasma DPP-IV activity for up to 4 h in BALB/c mice. The results show that compound 21a possesses in vitro and in vivo activities comparable to those of NVP-LAF237 (4), which is in clinical development.

Inhibition of dipeptidyl peptidase IV by novel inhibitors with pyrazolidine scaffold

Inhibition of dipeptidyl peptidase IV (DPP-IV) activity has been reported to improve nutrient-stimulated insulin secretion through the stabilization of glucagon-like peptide (GLP-1). In the present study, we identified novel DPP-IV inhibitors of pyrazolidine derivatives (Compounds 1 and 2) and characterized their biological effects in vitro and in vivo. Compound 1, an isoleucine pyrazolidide with a phenyl urea group, inhibited rat plasma DPP-IV, porcine kidney DPP-IV, as well as human Caco-2 DPP-IV with IC 50 values of 1.70, 2.26, and 2.02 μM, respectively. Because of the poor pharmacokinetic properties of Compound 1, further optimization was carried out, leading to the discovery of Compound 2, which had similar in vitro activities. Compound 2 acted as a selective and competitive inhibitor of DPP-IV. MALDI-TOF mass spectrometric analysis proved that the compound (20 μM) effectively blocked the degradation of active GLP-1 peptide by 61%. Although similar in in vitro potency, marked improvement of in vivo efficacy and pharmacokinetic properties was seen with Compound 2. Oral administration of Compound 2 resulted in potent and rapid inhibition of circulating DPP-IV in C57BL/6J mice, with ED 50 values of 26 mg/kg (s.c.) and 42 mg/kg (p.o.). In addition, this compound improved glucose tolerance in ob/ob mice, as determined by an oral glucose tolerance test (OGTT). These results indicate that Compound 2 is a potent and selective DPP-IV inhibitor with oral anti-hyperglycemic activity in vivo.

1-[[(3-hydroxy-1-adamantyl)amino]acetyl]-2-cyano-(S)-pyrrolidine: a potent, selective, and orally bioavailable dipeptidyl peptidase IV inhibitor with antihyperglycemic properties.

Dipeptidyl peptidase IV (DPP-IV) inhibition has the potential to become a valuable therapy for type 2 diabetes. The synthesis and structure-activity relationship of a new DPP-IV inhibitor class, N-substituted-glycyl-2-cyanopyrrolidines, are described as well as the path that led from clinical development compound 1-[2-[5-cyanopyridin-2-yl)amino]ethylamino]acetyl-2-cyano-(S)-pyrrolidine (NVP-DPP728, 8c) to its follow-up, 1-[[(3-hydroxy-1-adamantyl) amino]acetyl]-2-cyano-(S)-pyrrolidine (NVP-LAF237, 12j). The pharmacological profile of 12j in obese Zucker fa/fa rats along with pharmacokinetic profile comparison of 8c and 12j in normal cynomolgus monkeys is discussed. The results suggest that 12j is a potent, stable, selective DPP-IV inhibitor possessing excellent oral bioavailability and potent antihyperglycemic activity with potential for once-a-day administration.

1-[2-[(5-Cyanopyridin-2-yl)amino]ethylamino]acetyl-2-(S)-pyrrolidinecarbonitrile: A Potent, Selective, and Orally Bioavailable Dipeptidyl Peptidase IV Inhibitor with Antihyperglycemic Properties

Dipeptidyl peptidase IV (DPP-IV) inhibition has the potential to become a valuable therapy for type 2 diabetes. We report the first use of solid-phase synthesis in the discovery of a new DPP-IV inhibitor class and a solution-phase synthesis that is practical up to the multikilogram scale. One compound, NVP-DPP728 (2), is profiled as a potent, selective, and short-acting DPP-IV inhibitor that has excellent oral bioavailability and potent antihyperglycemic activity.