Pharmacokinetic and protein binding profile of peptidomimetic DPP-4 inhibitor - Teneligliptin in rats using liquid chromatography-tandem mass spectrometry

Effect of Teneligliptin 20 mg Twice Daily on Glucagon-Like Peptide-1 Levels and Its Influence on Non-Glycemic Components in Non-Diabetic Obese Individuals

Background and Aims: Teneligliptin is an oral antidiabetic agent, it can persevere glucagon-like peptide-1 (GLP-1) by inhibiting dipeptidyl peptidase enzyme. In addition, it has rare incidence of hypoglycemia. Hence, this study aimed to test the effect of teneligliptin 20 mg twice daily along with low carbohydrate diet and physical exercise on change of body weight and insulin resistance in nondiabetic obese subjects. Materials and Methods: It is a prospective, randomized, double-blind, placebo-controlled, parallel group study carried out at outpatient department of an endocrinology hospital over the period of 48 weeks. Teneligliptin 20 mg twice daily 30 min before food (low carbohydrate diet [LCD]) with regular physical exercise, and control group was kept with placebo twice daily 30 min before food LCD with regular physical exercise. This study was registered in clinical trial registry of India [CTRI/2020/02/023329]. Results: A total of 150 nondiabetic obese subjects were randomized into test (n = 75) and control groups (n = 75). At the end of 48 weeks there was significant improvement in GLP-1, simplified nutrition assessment questionnaire (SNAQ) score, homeostasis model assessment of insulin resistance (HOMA-IR), triglycerides (TG), and body weight. The mean difference and 95% confidence interval of GLP-1 (pg/mL) was 76.42 (44.42-148.41) (P = 0.37); SNAQ score, -1.64 (-2.48 to -0.81) (P = 0.000); HOMA-IR, -0.9 (-0.59 to -0.38) (P = 0.000); TG (mg/dL) -29.37 (-44.46 to -14.07) (P = 0.000); reduction of body weight (kilograms) -3.09 (-6.11 to -0.07) (P = 0.043). Conclusion: Findings of this study reveals that teneligliptin-treated group showed significant improvement in GLP-1 levels, reduced insulin resistance, body weight, TG, appetite, and metabolic syndrome. Teneligliptin is well tolerated, except in upper respiratory tract infections. CTR number: CTRI/2020/02/023329.

Current trends and future prospects of drug repositioning in gastrointestinal oncology

Gastrointestinal (GI) cancers comprise a significant number of cancer cases worldwide and contribute to a high percentage of cancer-related deaths. To improve survival rates of GI cancer patients, it is important to find and implement more effective therapeutic strategies with better prognoses and fewer side effects. The development of new drugs can be a lengthy and expensive process, often involving clinical trials that may fail in the early stages. One strategy to address these challenges is drug repurposing (DR). Drug repurposing is a developmental strategy that involves using existing drugs approved for other diseases and leveraging their safety and pharmacological data to explore their potential use in treating different diseases. In this paper, we outline the existing therapeutic strategies and challenges associated with GI cancers and explore DR as a promising alternative approach. We have presented an extensive review of different DR methodologies, research efforts and examples of repurposed drugs within various GI cancer types, such as colorectal, pancreatic and liver cancers. Our aim is to provide a comprehensive overview of employing the DR approach in GI cancers to inform future research endeavors and clinical trials in this field.

Repurposing of Omarigliptin as a Neuroprotective Agent Based on Docking with A2A Adenosine and AChE Receptors, Brain GLP-1 Response and Its Brain/Plasma Concentration Ratio after 28 Days Multiple Doses in Rats Using LC-MS/MS

The authors in the current work suggested the potential repurposing of omarigliptin (OMR) for neurodegenerative diseases based on three new findings that support the preliminary finding of crossing BBB after a single dose study in the literature. The first finding is the positive results of the docking study with the crystal structures of A_2A adenosine (A2AAR) and acetylcholine esterase (AChE) receptors. A2AAR is a member of non-dopaminergic GPCR superfamily receptor proteins and has essential role in regulation of glutamate and dopamine release in Parkinson’s disease while AChE plays a major role in Alzheimer’s disease as the primary enzyme responsible for the hydrolytic metabolism of the neurotransmitter acetylcholine into choline and acetate. Docking showed that OMR perfectly fits into A2AAR binding pocket forming a distinctive hydrogen bond with Threonine 256. Besides other non-polar interactions inside the pocket suggesting the future of the marketed anti-diabetic drug (that cross BBB) as a potential antiparkinsonian agent while OMR showed perfect fit inside AChE receptor binding site smoothly because of its optimum length and the two fluorine atoms that enables quite lean fitting. Moreover, a computational comparative study of OMR docking, other 12 DPP-4 inhibitors and 11 SGLT-2 inhibitors was carried out. Secondly, glucagon-like peptide-1 (GLP-1) concentration in rats’ brain tissue was determined by the authors using sandwich GLP-1 ELISA kit bio-analysis to ensure the effect of OMR after the multiple doses’ study. Brain GLP-1 concentration was elevated by 1.9-fold following oral multiple doses of OMR (5 mg/kg/day, p.o. for 28 days) as compared to the control group. The third finding is the enhanced BBB crossing of OMR after 28 days of multiple doses that had been studied using LC-MS/MS method with enhanced liquid–liquid extraction. A modified LC-MS/MS method was established for bioassay of OMR in rats’ plasma (10–3100 ng/mL) and rats’ brain tissue (15–2900 ng/mL) using liquid–liquid extraction. Alogliptin (ALP) was chosen as an internal standard (IS) due to its LogP value of 1.1, which is very close to the LogP of OMR. Extraction of OMR from samples of both rats’ plasma and rats’ brain tissue was effectively achieved with ethyl acetate as the extracting solvent after adding 1N sodium carbonate to enhance the drug migration, while choosing acetonitrile to be the diluent solvent for the IS to effectively decrease any emulsion between the layers in the stated method of extraction. Validation results were all pleasing including good stability studies with bias of value below 20%. Concentration of OMR in rats’ plasma were determined after 2 h of the latest dose from 28 days multiple doses, p.o, 5 mg/kg/day. It was found to be 1295.66 ± 684.63 ng/mL estimated from the bio-analysis regression equation. OMR passed through the BBB following oral administration and exhibited concentration of 543.56 ± 344.15 ng/g in brain tissue, taking in consideration the dilution factor of 10. The brain/plasma concentration ratio of 0.42 (543.56/1295.66) was used to illustrate the penetration power through the BBB after the multiple doses for 28 days. Results showed that OMR passed through the BBB more effectively in the multiple dose study as compared to the previously published single dose study by the authors. Thus, the present study suggests potential repositioning of OMR as antiparkinsonian agent that will be of interest for researchers interested in neurodegenerative diseases.

Development and Validation of a Rapid and Sensitive Method for the Simultaneous Estimation of Gemigliptin and Teneligliptin in Bulk and Dosage Forms by Using Liquid Chromatography-tandem Mass Spectrometry

Background:

A simple and sensitive ultra-performance liquid chromatography-mass spectrometry method was developed and validated to measure the concentrations of gemigliptin (GEM) and teneligliptin (TEN) using pioglitazone (PIO) as an internal standard.

Methods:

Chromatographic separation of two gliptins was achieved on a C-18 (100 mm X 2.1 mm, 2.7 μm) column using a mobile phase consisting of formic acid in water (0.1 % v/ v): acetonitrile in gradient elution. Electrospray ionization (ESI) source was operated in positive mode (ionization). Targeted MS-MS mode on a quadrupole time of flight (Q-TOF) mass spectrometer was used to quantify the drugs utilizing the mass transitions of 490.1 (m/z), 427.2 (m/z) and 357.1 (m/z) for GEM, TEN and PIO, respectively.

Results:

As per ICH Q2R1 guidelines, a detailed validation of the method was carried out and the standard curves were found to be linear between the concentration ranges of 509.8-1529.4 ng mL-1 and 510.6-1531.7 ng mL-1 for GEM and TEN, respectively. Precision and accuracy results were found to be within the acceptable limits. The mean recovery was found to be 98.8± 0.76 % (GEM) and 98.6 ±0.98 % (TEN), respectively.

Conclusions:

The optimized validated UPLC-QTOF (MS-MS) method offered the advantage of shorter analytical times and higher sensitivity and selectivity to the nanogram level.

Overcoming cancer therapeutic bottleneck by drug repurposing

Ever present hurdles for the discovery of new drugs for cancer therapy have necessitated the development of the alternative strategy of drug repurposing, the development of old drugs for new therapeutic purposes. This strategy with a cost-effective way offers a rare opportunity for the treatment of human neoplastic disease, facilitating rapid clinical translation. With an increased understanding of the hallmarks of cancer and the development of various data-driven approaches, drug repurposing further promotes the holistic productivity of drug discovery and reasonably focuses on target-defined antineoplastic compounds. The "treasure trove" of non-oncology drugs should not be ignored since they could target not only known but also hitherto unknown vulnerabilities of cancer. Indeed, different from targeted drugs, these old generic drugs, usually used in a multi-target strategy may bring benefit to patients. In this review, aiming to demonstrate the full potential of drug repurposing, we present various promising repurposed non-oncology drugs for clinical cancer management and classify these candidates into their proposed administration for either mono- or drug combination therapy. We also summarize approaches used for drug repurposing and discuss the main barriers to its uptake.

A rapid and sensitive UPLC-MS/MS method for the determination of flibanserin in rat plasma: application to a pharmacokinetic study

Background

In this work, we aim to develop and validate a fast, simple, and sensitive method for the quantitative determination of flibanserin and the exploration of its pharmacokinetics.

Methods

Ultra-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was the method of choice for this investigation and carbamazepine was selected as an internal standard (IS). The plasma samples were processed by one-step protein precipitation using acetonitrile. The highly selective chromatographic separation of flibanserin and carbamazepine (IS) was realised using an Agilent RRHD Eclipse Plus C18 (2.1 × 50 mm, 1.8 µ) column with a gradient mobile phase consisting of 0.1% formic acid in water and acetonitrile. The analytes were detected using positive-ion electrospray ionization mass spectrometry via multiple reaction monitoring (MRM). The target fragment ions were m/z 391.3 → 161.3 for flibanserin and m/z 237.1 → 194 for carbamazepine (IS). The method was validated by linear calibration plots over the range of 100-120,000 ng/mL for flibanserin (R² = 0.999) in rat plasma.

Results

The extraction recovery of flibanserin was in the range of 91.5-95.8%. The determined inter- and intra-day precision was below 12.0%, and the accuracy was from - 6.6 to 12.0%. No obvious matrix effect and astaticism was observed for flibanserin. The target analytes were long-lasting and stable in rat plasma for 12 h at room temperature, 48 h at 4 °C, 30 days at - 20 °C, as well as after three freeze-thaw cycles (from - 20 °C to room temperature). The proposed method has been fully validated and successfully applied to the pharmacokinetic study of flibanserin.

Repositioning of Omarigliptin as a once-weekly intranasal Anti-parkinsonian Agent

Drug repositioning is a revolution breakthrough of drug discovery that presents outstanding privilege with already safer agents by scanning the existing candidates as therapeutic switching or repurposing for marketed drugs. Sitagliptin, vildagliptin, saxagliptin & linagliptin showed antioxidant and neurorestorative effects in previous studies linked to DPP-4 inhibition. Literature showed that gliptins did not cross the blood brain barrier (BBB) while omarigliptin was the first gliptin that crossed it successfully in the present work. LC-MS/MS determination of once-weekly anti-diabetic DPP-4 inhibitors; omarigliptin & trelagliptin in plasma and brain tissue was employed after 2 h of oral administration to rats. The brain/plasma concentration ratio was used to deduce the penetration power through the BBB. Results showed that only omarigliptin crossed the BBB due to its low molecular weight & lipophilic properties suggesting its repositioning as antiparkinsonian agent. The results of BBB crossing will be of interest for researchers interested in Parkinson's disease. A novel intranasal formulation was developed using sodium lauryl sulphate surfactant to solubilize the lipophilic omarigliptin with penetration enhancing & antimicrobial properties. Intranasal administration showed enhanced brain/plasma ratio by 3.3 folds compared to the oral group accompanied with 2.6 folds increase in brain glucagon-like peptide-1 concentration compared to the control group.

Mechanistic study for the simultaneous determination of metformin and teneligliptin in human plasma using hydrophilic interaction liquid chromatography–MS/MS

Aim: A simple, selective and sensitive hydrophilic interaction liquid chromatography-MS/MS method is developed for the simultaneous determination of metformin (MET) and teneligliptin (TEN) in human plasma using deuterated internal standards. The mechanism of retention of analytes was studied by varying the proportion of organic diluent, buffer strength, pH of the mobile phase and temperature. Results: The results showed a mixed-mode mechanism comprising of hydrophilic (partition) and electrostatic interaction (ion exchange) for MET and essentially hydrophilic for TEN. The linear calibration curves were established in the concentration range of 1.0–1000 ng/ml for MET and 0.50–750 ng/ml for TEN. Conclusion: The method was applied to determine plasma concentration of MET and TEN in healthy subjects.