Selective Dipeptidyl Peptidase-4 Inhibitor Research Articles

SITAGLIPTIN AMELIORATES ATORVASTATIN INDUCED HEPATOTOXICITY IN RATS

Atorvastatin (ATOR) is the most widely used statin for the treatment of hypercholesterolemia, which is the most common cause of severe liver injury. Sitagliptin is a selective dipeptidyl peptidase-4 inhibitor (DPP4-I) used clinically as oral anti-diabetic agent. This study aimed to identify the effect of sitagliptin (SITA) pretreatment against Atorvastatin (ATOR) induced hepatotoxicity in albino rats. Twenty-five rats were divided into five groups (5 rats in each); normal control, ATOR, SITA and two sitagliptin groups, which pretreated with sitagliptin 10 and 20 mg/kg/day in combination with ATOR 20mg /kg / day for eight consecutive days prior to ATOR. The results revealed that ATOR induced noticeable hepatic injury in the form of moderate Hepatoportal + sinusoidal congestion, all Zonal changes, moderate Cloudy swelling + hydropic degeneration, moderate Fatty change and mild Apoptosis. Biochemical analysis exposed a significant rise in the serum transaminases, alkaline phosphatase and lactate dehydrogenase in ATOR group. Increased Proinflammatory TNF-alpha, Oxidative stress MDA and depressed antioxidant system of GSH were evident in ATOR group. On the other hand, sitagliptin pretreatment significantly ameliorated all of the above mentioned biochemical, histopathological changes induced by ATOR. In conclusion, sitagliptin ameliorated the hepatotoxicity induced by atorvastatin. This effect was probably based through suppression of inflammatory, oxidative stress and apoptotic processes. Sitagliptin might exert beneficial effect on diabetic hepatic disorders which mandate further clinical research.

Synthesis and Anti-Diabetic Activity of an 8-Purine Derivative as a Novel DPP-4 Inhibitor in Obese Diabetic Zücker Rats.

Type 2 diabetes mellitus (T2DM) is one of the world's principal metabolic diseases characterized by chronic hyperglycemia. The gut incretin hormones, glucagon-like peptide 1 (GLP-1) and gastric inhibitory polypeptide (GIP), which has been proposed as a new treatment for T2DM, are extensively metabolized by Dipeptidyl peptidase 4 (DPP-4). Inhibitors of DPP-4 block the degradation of GLP-1 and GIP and may increase their natural circulating levels, favoring glycemic control in T2DM. A novel and potent selective inhibitor of DPP-4 with an 8-purine derived structure (1) has been developed and tested in vitro and in vivo in Zücker obese diabetic fatty (ZDF) rats, an experimental model of the metabolic syndrome and T2DM to assess the inhibitory activity using vildagliptin as reference standard. ZDF rats were subdivided into three groups (n = 7/group), control (C-ZDF), and those treated with compound 1 (Compound1-ZDF) and with vildagliptin (V-ZDF), both at 10 mg/kg/d rat body weight, in their drinking water for 12 weeks, and a group of lean littermates (ZL) was used. ZDF rats developed DM (fasting hyperglycemia, 425 ± 14.8 mg/dL; chronic hyperglycemia, HbA1c 8.5 ± 0.4%), compared to ZL rats. Compound 1 and vildagliptin reduced sustained HbAl1c (14% and 10.6%, P < 0.05, respectively) and fasting hyperglycemia values (24% and 19%, P < 0.05, respectively) compared to C-ZDF group (P < 0.001). Compound 1 and vildagliptin have shown a potent activity with an IC50 value of 4.92 and 3.21 µM, respectively. These data demonstrate that oral compound 1 administration improves diabetes in ZDF rats by the inhibitory effect on DPP-4, and the potential to be a novel, efficient and tolerable approach for treating diabetes of obesity-related T2DM, in ZDF rats.

Acute and Chronic Exposure to Linagliptin, a Selective Inhibitor of Dipeptidyl Peptidase-4 (DPP-4), Has an Effect on Dopamine, Serotonin and Noradrenaline Level in the Striatum and Hippocampus of Rats.

Linagliptin is a selective dipeptidyl peptidase-4 (DPP-4) inhibitor that indirectly elevates the glucagon-like peptide-1 (GLP-1) level. The aim of the present study was to check whether linagliptin has an influence on neurotransmission in rat brain. Rats were acutely and chronically exposed to linagliptin (10 and 20 mg/kg, intraperitoneally (i.p.)). Twenty-four hours later, the striatum and hippocampus were selected for further studies. In neurochemical experiments, using high-performance liquid chromatography with electrochemical detection (HPLC-ED), the concentrations of three major neurotransmitters-dopamine, serotonin and noradrenaline-and their metabolites were measured. The analysis of mRNA expression of dopamine (D1 and D2), serotonin (5-HT-1 and 5-HT-2) and noradrenaline (α1 and α2a) receptors was also investigated using real-time quantitative reverse transcription polymerase chain reaction (RQ-PCR) in the same brain areas. Linagliptin has the ability to influence the dopaminergic system. In the striatum, the elevation of dopamine and its metabolites was observed after repeated administration of that linagliptin, and in the hippocampus, a reduction in dopamine metabolism was demonstrated. Acute linagliptin exposure increases the serotonin level in both areas, while after chronic linagliptin administration a tendency for the mRNA expression of serotoninergic receptors (5-HT1A and 5-HT2A) to increase was observed. A single instance of exposure to linagliptin significantly modified the noradrenaline level in the striatum and intensified noradrenaline turnover in the hippocampus. The recognition of the interactions in the brain between DPP-4 inhibitors and neurotransmitters and/or receptors is a crucial step for finding novel discoveries in the pharmacology of DPP-4 inhibitors and raises hope for further applications of DPP-4 inhibitors in clinical practices.

Evaluation of the Drug-Induced Liver Injury Potential of Saxagliptin through Reactive Metabolite Identification in Rats.

A liver injury was recently reported for saxagliptin, which is a dipeptidyl peptidase-4 (DPP-4) inhibitor. However, the underlying mechanisms of saxagliptin-induced liver injury remain unknown. This study aimed to evaluate whether saxagliptin, a potent and selective DPP-4 inhibitor that is globally used for treating type 2 diabetes mellitus, binds to the nucleophiles in vitro. Four DPP-4 inhibitors, including vildagliptin, were evaluated for comparison. Only saxagliptin and vildagliptin, which both contain a cyanopyrrolidine group, quickly reacted with L-cysteine to enzyme-independently produce thiazolinic acid metabolites. This saxagliptin-cysteine adduct was also found in saxagliptin-administered male Sprague-Dawley rats. In addition, this study newly identified cysteinyl glycine conjugates of saxagliptin and 5-hydroxysaxagliptin. The observed metabolic pathways were hydroxylation and conjugation with cysteine, glutathione, sulfate, and glucuronide. In summary, we determined four new thiazoline-containing thiol metabolites (cysteine and cysteinylglycine conjugates of saxagliptin and 5-hydroxysaxagliptin) in saxagliptin-administered male rats. Our results reveal that saxagliptin can covalently bind to the thiol groups of cysteine residues of endogenous proteins in vivo, indicating the potential for saxagliptin to cause drug-induced liver injury.

The Safety and Efficacy of Combining Saxagliptin and Pioglitazone Therapy in Streptozocin-Induced Diabetic Rats.

Type 2 diabetes mellitus (T2DM) is a chronic progressive disease due to insulin resistance. Oxidative stress complicates the etiology of T2DM. Saxagliptin is a selective dipeptidyl peptidase-4 (DPP-4) inhibitor, while Pioglitazone is a thiazolidinedione insulin sensitizer. This study aimed to assess the effect of Saxagliptin and Pioglitazone monotherapy and combination therapy on the biochemical and biological parameters in streptozotocin (STZ)-induced diabetic rats. The study included thirty-five male albino rats. Diabetes mellitus was induced by intraperitoneal STZ injection (35 mg/kg). For a 1-month duration, rats were divided into five groups. Glucose homeostasis traits, lipid profiles, kidney functions, liver enzymes, and oxidative stress markers were measured. Gene expression of miRNA-29a, phosphoenolpyruvate carboxykinase (PEPCK), phosphoinositide-3-kinase (PI3K), and interleukin 1 beta (IL-1β) was assessed using qRT-PCR. At a 1-month treatment duration, combination therapy improves oxidative stress markers more than either drug alone. The combination therapy had significantly higher levels of SOD, catalase, and GSH and lower levels of MDA compared to the monotherapy. Additionally, the diabetic group showed a significant increase in the expression levels of miRNA-29a, PEPCK, and IL-1β and a significant decrease in PI3K compared to the normal control group. However, combination therapy of Saxagliptin and Pioglitazone was more effective than either Saxagliptin or Pioglitazone alone in reversing these results, especially for PEPCK and IL-1β. Our findings revealed that combining Saxagliptin and Pioglitazone improves glycemic control and genetic and epigenetic expression profiles, which play an essential regulatory role in normal metabolism.

Saxagliptin, a selective dipeptidyl peptidase-4 inhibitor, alleviates somatic cell aneugenicity and clastogenicity in diabetic mice.

Diabetes-related complications are becoming increasingly common as the global prevalence of diabetes increases. Diabetes is also linked to a high risk of developing cancer. This raises the question of whether cancer vulnerability is caused by diabetes itself or the use of antidiabetic drugs. Chromosomal instability, a source of genetic modification involving either an altered chromosomal number or structure, is a hallmark of cancer. Saxagliptin has been approved by the FDA for diabetes treatment. However, the detailed in vivo effects of prolonged saxagliptin treatment on chromosomal instability have not yet been reported. In this study, streptozotocin was used to induce diabetes in mice, and both diabetic and non-diabetic mice received saxagliptin for five weeks. Fluorescence in situ hybridization was conducted in combination with a bone marrow micronucleus test for measuring chromosomal instability. Our results indicated that saxagliptin is neither mutagenic nor cytotoxic, under the given treatment regimen. Diabetic mice had a much higher incidence of micronuclei formation, and a centromeric DNA probe was present inside the majority of the induced micronuclei, indicating that most of these were caused by chromosome nondisjunction. Conversely, diabetic mice treated with saxagliptin exhibited a significant decrease in micronuclei induction, which were centromeric-positive and centromeric-negative. Diabetes also causes significant biochemical changes indicative of oxidative stress, such as increased lipid peroxidation and decreased reduced/oxidized glutathione ratio, which was reversed by saxagliptin administration. Overall, saxagliptin, the non-mutagenic antidiabetic drug, maintains chromosomal integrity in diabetes and reduces micronuclei formation by restoring redox imbalance, further indicating its usefulness in diabetic patients.

Dipeptidyl Peptidase 4 Inhibitors in Type 2 Diabetes Mellitus Management: Pharmacophore Virtual Screening, Molecular Docking, Pharmacokinetic Evaluations, and Conceptual DFT Analysis

Dipeptidyl Peptidase 4 (DPP-4) expressed on the surface of many different cells is a promising target to develop new candidates for Type 2 diabetes mellitus (T2DM) management. In this light, we performed a computer-aided simulation involving 3-D pharmacophore screening, molecular docking, and drug-likeness assessment to identify novel potential DPP-4 inhibitors with an improved physicochemical profile to treat T2DM. In addition, global reactivity descriptors, including HOMO and LUMO energies, HOMO-LUMO gaps, and Fukui indices, were computed to confirm the essential structural features to achieve DPP-4 activity. The gathered outcomes recommend that eight out of 240 million compounds collected from eight pre-built databases (Molport, Chembl30, ChemDiv, ChemSpace, Mcule, Mcule-ultimate, LabNetwork, and ZINC) are drug-like and nontoxic, and may serve as starting points for designing novel, selective, and potent DPP-4 inhibitors. Furthermore, the success of the current workflow to identify DPP-4-potential inhibitors strengthens its potential efficiency to also predict natural compounds as novel adjutants or main therapy for T2DM or discover hit compounds of other targets.

Trelagliptin relieved cognitive impairment of diabetes mellitus rats: Involvement of PI3K/Akt/GSK-3β and inflammation pathway

Cognitive impairment frequently coexists with diabetes. Trelagliptin is a once-weekly taking selective dipeptidyl peptidase-4 (DPP-4) inhibitor and a long-term effective hypoglycemic medicine; nonetheless, its effects for the treatment of diabetes-related cognitive impairment have only sometimes been explored. In this study, a DM model was built using streptozotocin (STZ) and a high-fat diet (HFD). The morris water maze test on DM rats revealed a considerably reduced capacity for spatial learning and memory, but trelagliptin was able to restore function. Trelagliptin could lower the mRNA expression of inflammatory factors such IL-1β, TNF-α, and IL-6 in DM rats. It could also reduce the ratio of p-IKKα/IKKα, and the immunofluorescence result of NF-κB also demonstrated a drop. Trelagliptin partially restored dendritic spines and prevented the loss or shrinkage of neurons, respectively, according to the results of Nissl's staining and golgi staining. Furthermore, PI3K/Akt/GSK-3β has been activated, and synaptic plasticity has been modified during this process. In conclusion, trelagliptin improved the cognitive lesion in DM rats by suppressing the activation of the inflammatory route and by activating the PI3K/Akt/GSK-3β pathway at the same time, as well as interacting with the pathways that protect neurons, which still need further research.

Microbial gatekeepers: unraveling the role of the gut microbiota enzyme DPP4 in diabetes management

Wang et al. identified dipeptidyl peptidase 4 (DPP4) as a gut microbe-derived enzyme that impacts on host glucose metabolism. They further introduced a novel therapeutic, daurisoline-d4 (Dau-d4), a selective microbial DPP4 (mDPP4) inhibitor that shows promise in improving glucose tolerance, highlighting the potential of therapies that target both host enzymes and gut microbial enzymes.

Alogliptin exhibits multifaceted effects in thioacetamide-insulted rats: A novel approach to combating hepatic inflammation and fibrogenesis

Hepatic fibrosis arising from chronic liver injury is characterized by dysregulated healing, including hepatic stellate cell activation and excessive deposition of extracellular matrix proteins. Administration of the hepatotoxin thioacetamide (TAA) induces liver injury coupled to fibrogenesis in rodents, mimicking aspects of human disease. Alogliptin is a highly selective inhibitor of dipeptidyl peptidase-4 with purported antifibrotic actions. We investigated the protective effects of alogliptin against TAA-mediated hepatic fibrosis in rats. Adult male Sprague-Dawley rats received intraperitoneal injections of TAA (150 mg/kg) twice weekly for 6 weeks to induce liver fibrosis. A subset of rats also received daily oral alogliptin (20 mg/kg). At 6 weeks, liver injury and fibrosis were assessed by histology, hydroxyproline content, serum liver enzymes, inflammatory cytokines, oxidative stress markers, and genes related to inflammation, apoptosis, and fibrosis. TAA elicited necroinflammation, oxidative stress, upregulation of pro-fibrogenic mediators, increased hydroxyproline content, and excessive collagen deposition, indicating hepatic fibrosis. The administration of Alogliptin led to notable enhancements in liver histology, an extension in survival time, a decrease in hydroxyproline levels and the expression of fibrogenic genes, a reduction in inflammatory cytokines and oxidative stress, and mitigation of hepatocellular apoptosis in rats subjected to TAA treatment. Alogliptin displayed potent antifibrotic, antioxidant, and hepatoprotective properties in this model of toxic liver damage, likely by impeding NFκB while enhanced Nrf2 DNA binding activity which together modulate oxidative stress, inflammation, myofibroblast activation, and apoptosis. These results highlight the potential therapeutic value of alogliptin offering hope for improved treatment of hepatic fibrosis.

Microbial-host-isozyme analyses reveal microbial DPP4 as a potential antidiabetic target.

A mechanistic understanding of how microbial proteins affect the host could yield deeper insights into gut microbiota-host cross-talk. We developed an enzyme activity-screening platform to investigate how gut microbiota-derived enzymes might influence host physiology. We discovered that dipeptidyl peptidase 4 (DPP4) is expressed by specific bacterial taxa of the microbiota. Microbial DPP4 was able to decrease the active glucagon like peptide-1 (GLP-1) and disrupt glucose metabolism in mice with a leaky gut. Furthermore, the current drugs targeting human DPP4, including sitagliptin, had little effect on microbial DPP4. Using high-throughput screening, we identified daurisoline-d4 (Dau-d4) as a selective microbial DPP4 inhibitor that improves glucose tolerance in diabetic mice.

Prediction of Passive Membrane Permeability of Linagliptin

Linagliptin is a highly selective inhibitor of dipeptidyl peptidase-4 and therefore clinically utilized to treat adults with type 2 diabetes mellitus. The objective of this study was to predict how the ions normally found in extracellular or intracellular fluids within the body system will influence the linagliptin’s rate of passive diffusion across a cell membrane. The methodology involved measuring linagliptin partition coefficient in a chloroform-water system containing the salts at 25 oC by the shake flask method. The results indicate that at the highest concentration (0.5 M) of the salts studied, sodium chloride was found to give the highest partition coefficient value when compared to the control. In conclusion, physiological ions would have little or no effect on the drug’s molecular state within extracellular or intracellular fluid as the salts failed to significantly alter the partition coefficient of the drug, hence will not alter passive membrane permeability of linagliptin.

Metformin and sitagliptin fixed combination as the optimal choice in solving current problems in the type 2 diabetes mellitus treatment

The complex pathogenesis of type 2 diabetes mellitus (DM) is the basis for providing the therapeutic treatment for various disorders, which ensures a better glucose-lowering potential and maintenance of glycemic control as the disease progresses. A key reason for poor glycemic control is clinical inertia, which can be overcome by using antidiabetic fixed-dose combinations (FC). Their use improves glycemic control, as the multidirectional action of the combination components on the pathogenetic mechanisms of type 2 diabetes leads to increased pharmacological effects. The PK of metformin and sitagliptin is preferable in terms of glucose-lowering efficacy, safety and clinical benefits. The mechanism of action of metformin is not associated with the stimulation of insulin secretion by β-cells, but results from the drug’s effect on insulin sensitivity at the level of the liver, muscle and adipose tissue, although the effect on hepatic glucose production is the prevailing one. The mechanism of action of sitagliptin, a highly selective inhibitor of dipeptidyl peptidase-4, is additional to the basic pharmacological effects of metformin, which are caused by several mechanisms not associated with stimulation of insulin secretion by β-cells. The simultaneous use of sitagliptin and metformin has additive effects on the increase of glucagon-like peptide-1 levels. This action is implemented through various mechanisms, while metformin increases the release, and sitagliptin inhibits the active degradation of glucagon-like peptide-1. The article emphasizes the importance of rational combinations of glucose-lowering drugs, the need for a personalized approach to the choice of medicines. The current possibilities of sugar-reducing therapy, the issues of efficacy, safety and benefits of PK of metformin and sitagliptin are discussed using modern evidence-based data.

Sitagliptin Potentiates the Anti-Neoplastic Activity of Doxorubicin in Experimentally-Induced Mammary Adenocarcinoma in Mice: Implication of Oxidative Stress, Inflammation, Angiogenesis, and Apoptosis

Sitagliptin (STG) is a highly selective dipeptidyl peptidase-4 inhibitor recently used in the treatment of type 2 diabetes. The current study aimed to investigate the anti-neoplastic effect of STG alone and in combination with Doxorubicin (Dox), a known chemotherapeutic agent but with ominous side effects. After intramuscular inoculation of 2 × 106 Ehrlich tumor cells, Female Swiss mice were divided into tumor-bearing control, STG-treated, Dox-treated, and a combination of STG and Dox-treated groups. The results showed a significant reduction in the tumor growth of the treated animals in comparison with those of the positive control group with a more prominent effect in the co-treated group. Where, the anti-proliferative and apoptotic effect of STG, and its chemo-sensitizing ability, when used in combination with Dox, was mediated by modulation of oxidative stress (MDA and GSH), attenuation of tumor inflammation (IL-6 and IL-1β), and angiogenesis (VEGF), suppressing proliferation (β-catenin and cyclin-D1) and enhancement of apoptosis (survivin, p53, caspase 3). Thus, in conclusion, STG as adjunctive therapy for Dox could be a strategy for the treatment of breast cancer patients, by their ability in hindering cell proliferation and minimizing the associated oxidative and inflammatory adverse reactions.

Effects of linagliptin on morphine dependence in larval zebrafish (Danio rerio)

Abstract Drug addiction is a chronic, recurrent disease of the central nervous system that leads to the development of comorbidities and premature death. Despite extensive scientific research concerning addiction, no effective method of addiction pharmacotherapy has been known so far. Glucagon-like peptide 1 has been suggested to play a role in the rewarding effect of addictive drugs. Linagliptin is a selective dipeptidyl peptidase-4 inhibitor that suppresses the rapid degradation of endogenous glucagon-like peptide-1. In clinical practice, it is used as an antidiabetic drug, but recent studies have confirmed its role in the activity of the central nervous system. This pilot study was conducted to ascertain whether linagliptin might influence morphine dependence – a locomotor activity test was carried out to assess the intensity of morphine withdrawal symptom. The obtained results clearly confirmed that linagliptin (0.01 and 0.1 mM) reduced the locomotor activity in morphine-dependent larval zebrafish. The undertaken experiments clearly indicates that linagliptin is involved in the addictive effects of morphine, thus, further studies on higher organisms should be carried out.

Real World Study of Effectiveness of Gemigliptin Add-On Therapy in Type 2 Diabetes Mellitus

Background: Dipeptidyl peptidase-4 (DPP-4) inhibitors are a new class of oral antidiabetic agents that increase endogenous levels of incretin hormones and lead to an increased insulin level and a reduced glucagon level in a glucose-dependent way. Gemigliptin, is a potent, selective, competitive, and long-acting DPP-4 inhibitor. The objective of our study was to evaluate the realworld efficacy and safety of gemigliptin. Materials and methods: A real-world prospective, observational, single-center study conducted in the Endocrinology Department, of a tertiary care hospital. 60 patients were included with 22 (36.7%) female patients. The treatment options consisted of uncontrolled metformin monotherapy, dual combination therapy, triple oral anti-hyperglycemic agents, metformin, and basal insulin combination. Weight, body mass index (BMI), fasting plasma glucose (FPG), 2 hours post postprandial glucose (PPG), HbA1c% were documented at baseline and followed up at 3 months. Results: The baseline HbA1c, FPG and PPG were 9.50 ± 2.24 %, 176.71 ± 67.076 mg/dL, 243.37 ± 93.97 mg/dl respectively. After 3 months of additional gemigliptin therapy, HbA1c, FPG, and PPG were significantly reduced to 8.24 ± 1.83%, 144.32 ± 50.664, 184.93 ± 69.66 respectively. Conclusions: In real world settings, gemigliptin, a new DPP-4 inhibitor was found to be effective, safe and well tolerated as add-on therapy in adult type 2 diabetes mellitus (T2DM) subjects.

Disposition study of the novel dipeptidyl peptidase 4 inhibitor cetagliptin in rats

Dipeptidyl peptidase-4 (DPP-4) inhibitor is a class of oral antihyperglycemic agents and therapeutic approach for type 2 diabetes. Cetagliptin is a novel oral and selective DPP-4 inhibitor and developed as a promising candidate for treatment of type 2 diabetes mellitus. This study aimed to evaluate the metabolism and excretion of cetagliptin in Sprague-Dawley (SD) rats, and to detect and identify metabolites of cetagliptin. The SD rats were administered with a single oral dose of 6 mg/kg with approximately 100 µCi of [14C] cetagliptin. The mean total recovery of radioactivity was 90.20% within 168h in SD rats excreta. Cetagliptin was the major radioactive component in SD rats plasma, urine and eliminated primarily by faecal excretion. The recovery of cetagliptin in urine and feces was 25.15% and 13.85% of the dose, respectively. Cetagliptin was well absorbed after oral administration in SD rats based on the total recovery of radioactivity in BDC SD rats bile and urine. Six major metabolites were observed and identified in SD rats, comprising 0.20 to 4.53% of total plasma AUC. These major metabolites were the hydroxylated, N-sulphate and N-carbamoyl glucuronic acid conjugates of the cetagliptin, two metabolites formed by glucuronide of a hydroxylated metabolite.

Assessment of suitability of saxagliptin hydrochloride for development of controlled release parenteral formulation by preformulation studies

The main objective of pre-formulation study is to develop the stable, elegant, safe and effective drug delivery system by establishing drug kinetic profile, formulation compatibility with different excipients and physico-chemical parameters of new drug molecules. This could provide key evidence for implementing formulation design or requirement of the molecular alteration. So, in the present study preformulation studies were performed on Saxagliptin Hydrochloride (SXG) to assess its suitability for parenteral formulation. SXG is a potent and selective reversible inhibitor of dipeptidyl peptidase-4 used to treat type –II diabetes mellitus. The authenticity of SXG was established by differential scanning calorimetry (DSC) and fourier transform infrared spectroscopy(FTIR) spectra. An ultraviolet–visible (UV) spectrophotometric and high performance liquid chromatography (HPLC) methods were employed for determination of SXG in bulk API (active pharmaceutical ingredient). The UV method was linear within the range of 1-40 μg/ml. The proposed methodology is robust which can be concluded from the lower percentage standard deviation percentage co efficient of variance (% CV) values of intraday and inter day variability. The retention time was observed 1.3 min of SXG in HPLC method. The higher regression coefficient value (0.999) indicates the methodology is robust.

Linagliptin, a Selective Dipeptidyl Peptidase-4 Inhibitor, Reduces Physical and Behavioral Effects of Morphine Withdrawal.

(1) Background: Recent data indicate that receptors for GLP-1 peptide are involved in the activity of the mesolimbic system. Thus, the purpose of the present study was to examine the effect of the selective dipeptidyl peptidase-4 (DPP-4) inhibitor, linagliptin, on morphine dependence in mice. (2) Methods: Morphine dependence in mice was obtained by administration of increasing doses of morphine for eight consecutive days, twice a day. On the 9th day of the experiment, the naloxone-induced (2 mg/kg, ip) morphine withdrawal signs (jumping) were assessed. Moreover, behavioral effects of short-term (60 h after morphine discontinuation) and long-term (14 days after morphine discontinuation) morphine withdrawal were observed. In terms of behavioral effects, the depressive effect in the forced swim test and anxiety in the elevated plus maze test were investigated. Locomotor activity of mice was also studied. (3) Results: The administration of linagliptin (10 and 20 mg/kg, ip) for 8 consecutive days before morphine injections significantly diminished the number of naloxone-induced morphine withdrawal signs (jumping) in mice. In addition, the cessation of morphine administration induced depressive behavior in mice which were observed during short- and long-term morphine withdrawal. Linagliptin administered during morphine withdrawal significantly reduced the depressive behavior in studied mice. Furthermore, the short-term morphine withdrawal evoked anxiety which also was reduced by linagliptin in mice. (4) Conclusions: The present study reveals that GLP-1 receptors are involved in morphine dependence. What is more, linagliptin might be a valuable drug in attenuating the physical symptoms of morphine dependence. It might be also a useful drug in reducing emotional disturbances which may develop during the morphine withdrawal period.

Anagliptin alleviates lipopolysaccharide-induced inflammation, apoptosis and endothelial dysfunction of lung microvascular endothelial cells.

It has been reported that dipeptidyl peptidase-4 (DPP4) inhibition protects against acute lung injury (ALI). Anagliptin is a novel selective inhibitor of DPP4 but its role in ALI has not been studied. The present study aimed to investigate the effects of anagliptin on lipopolysaccharide (LPS)-induced human pulmonary microvascular endothelial cell (HPMVEC) injury, as well as its underlying mechanism. HPMVECs were exposed to LPS in the presence or absence of anagliptin co-treatment. MTT assay was used to evaluate cell viability and nitric oxide (NO) production was detected using a commercial kit. DPP4 and pro-inflammatory cytokine expression levels, apoptosis and migration were assessed via reverse transcription-quantitative PCR, western blotting, TUNEL staining and wound healing assay, respectively. Western blot analysis was performed to assess expression levels of proteins involved in NF-κB signaling, cell apoptosis and migration, as well as high mobility group box 1 (HMGB1)/receptor for advanced glycation end products (RAGE). LPS decreased cell viability and NO production, but elevated expression of DPP4 in HPMVECs. LPS promoted pro-inflammatory cytokine expression, NF-κB activation and cell apoptosis, but inhibited cell migration and phosphorylated-AKT/endothelial NO synthase expression. Anagliptin co-treatment significantly restored all of these effects. Mechanistically, the upregulation of HMGB1/RAGE expression induced by LPS was markedly blocked by anagliptin. In conclusion, anagliptin alleviated inflammation, apoptosis and endothelial dysfunction in LPS-induced HPMVECs via modulating HMGB1/RAGE expression. These data provide a basis for use of anagliptin in ALI treatment.