LC/QTOF/MS/MS characterization, molecular docking and in silico toxicity prediction studies on degradation products of anagliptin

Analytical and Bioanalytical Methods for the Determination of Dipeptidyl Peptidase-4 Inhibitors in Various Matrices: A Comprehensive Review

BACKGROUND

DPP-4 inhibitors, or gliptins, are new oral antidiabetic drugs for type 2 diabetes. They help to regulate insulin and glucagon. These drugs have the advantage of a lower risk of hypoglycemia compared to some other diabetes medications and are typically prescribed when metformin and sulphonylureas have become less effective.

OBJECTIVE

This review analyses a range of analytical and bioanalytical methods for DPP-4 inhibitors, that use spectroscopic techniques, chromatographic, and hyphenated techniques for analysis. So far, no review comprising all DPP-4 inhibitors has been presented. The primary objective of this review is to present the analysts with various analytical and bioanalytical methods for the quantification and estimation of DPP-4 inhibitors in different matrices.

METHODS

To improve understanding, a review was carried out by creating a database of pre-existing research from digital sources such as ScienceDirect, and PubMed. The methodology is shown in the flowchart of the literature selection process.

CONCLUSION

The comprehensive assessment of methods for analysing DPP-4 inhibitors can be a valuable resource for researchers and healthcare practitioners. Hitherto, no review encompassing all DPP-4 inhibitors has been presented. Therefore, gaps in the data available on a particular subject, need to be required to collect data on a particular construct. The review suggests that chromatographic techniques were majorly used for analysis wherein solvents like acetonitrile, methanol, and buffer solutions were used as mobile phases that can deteriorate HPLC columns and equipment. So, scientists could investigate new methods for the assessment of DPP-4 inhibitors using more eco-friendly solvents.

Identification and Characterization of Rotigotine Degradation Products by HPLC Coupled DAD and CAD Detectors and HRMS Through Q-Orbitrap and Electrospray Ionization

Rotigotine (RTG) is a dopamine agonist used in the treatment of Parkinson's disease. As it is susceptible to oxidation, stability studies must be carefully designed for the identification and characterization of all possible degradation products. Here, RTG degradation was evaluated according to the International Conference on Harmonization guidelines under various stress conditions, including acidic and basic hydrolysis, oxidative, metallic, photolytic, and thermal conditions. Additionally, more severe stress conditions were applied to induce RTG degradation. Significant degradation was only observed under oxidative and photolytic conditions. The samples were analyzed by high performance liquid chromatography coupled to photodiode array detectors, charged aerosol, and high-resolution mass spectrometry. Chromatographic analyses revealed the presence of eight substances related to RTG, four of which were already described and were qualified impurities (impurities B, C, K and E) and four new degradation products (DP-1 - DP-4), whose structures were characterized by high-resolution mass spectrometry through Q-Orbitrap and electrospray ionization. In the stress testing of the active pharmaceutical ingredient in solid form, significant RTG degradation was observed in the presence of the oxidative matrix. The results corroborate the literature that confirm the high susceptibility of RTG to oxidation and the importance of using different detectors to detect degradation products in forced degradation studies.

Metabolism and Chemical Degradation of New Antidiabetic Drugs (Part II): A Review of Analytical Approaches for Analysis of Gliptins

This paper is part II of the review on metabolism and chemical degradation of new antidiabetic drugs from glutides, gliflozins and gliptins. It is well known that metabolism data can be helpful for deriving safe levels of degradation impurities and their qualifying as far as toxicological aspects are concerned. As a result, it could link the quality of respective pharmaceutical products to clinical practice and patients. Some overlapping pathways of transformations of these important drugs of different chemical structures and different mechanisms of action were discussed. At the same time, the paper summarized interesting analytical tools for conducting modern drug metabolism as well as drug degradation experiments. The methods described here include liquid chromatography (LC) and liquid chromatography coupled with mass spectrometry (LC-MS or LC-MS/MS), which are widely used for detection and quantitative measurements of the drugs, their metabolites and degradants, as well as radiometric methods that are suitable for pharmacokinetic experiments. Special attention was paid to dedicated types of packing in chromatographic columns, as well as to special solutions in the LC-MS procedures. The present part addresses the analytical approaches elaborated for examining the metabolism and degradation pathways of gliptins that are dipeptidyl peptidase 4 (DPP-4) inhibitors.

Molecular Structure-Based Screening of the Constituents of Calotropis procera Identifies Potential Inhibitors of Diabetes Mellitus Target Alpha Glucosidase

Diabetes mellitus is a disorder characterized by higher levels of blood glucose due to impaired insulin mechanisms. Alpha glucosidase is a critical drug target implicated in the mechanisms of diabetes mellitus and its inhibition controls hyperglycemia. Since the existing standard synthetic drugs have therapeutic limitations, it is imperative to identify new potent inhibitors of natural product origin which may slow carbohydrate digestion and absorption via alpha glucosidase. Since plant extracts from Calotropis procera have been extensively used in the treatment of diabetes mellitus, the present study used molecular docking and dynamics simulation techniques to screen its constituents against the receptor alpha glucosidase. Taraxasterol, syriogenin, isorhamnetin-3-O-robinobioside and calotoxin were identified as potential novel lead compounds with plausible binding energies of −40.2, −35.1, −34.3 and −34.3 kJ/mol against alpha glucosidase, respectively. The residues Trp⁴⁸¹, Asp⁵¹⁸, Leu⁶⁷⁷, Leu⁶⁷⁸ and Leu⁶⁸⁰ were identified as critical for binding and the compounds were predicted as alpha glucosidase inhibitors. Structurally similar compounds with Tanimoto coefficients greater than 0.7 were reported experimentally to be inhibitors of alpha glucosidase or antidiabetic. The structures of the molecules may serve as templates for the design of novel inhibitors and warrant in vitro assaying to corroborate their antidiabetic potential.

Recent Progresses in Analytical Perspectives of Degradation Studies and Impurity Profiling in Pharmaceutical Developments: An Updated Review

Forced degradation studies have been used to simplify analytical methodology development and achieve a deeper knowledge about the inherent stability of active pharmaceutical ingredients (API) and drug products. This provides insight into degradation species and pathways. Identification of impurities in pharmaceutical products is closely related to the selection of the most appropriate analytical methods like HPLC-UV, LC-MS/MS, LC-NMR, GC-MS, and capillary electrophoresis. Herein, recent trends in analytical perspectives during 2018-April 14, 2021, are discussed based on forced and impurity degradation profiling of pharmaceuticals. Literature review showed that several methods have been used for experimental design and analysis conditions such as matrix type, column type, mobile phase, elution modes, detection wavelengths, and therapeutic category. Thus, since these factors influence the separation and identification of the impurities and degradation products, we attempted to perform a statistical analysis for the developed methods according to the abovementioned factors.

Spectrophotometric method development and validation for simultaneous estimation of Anagliptin and Metformin HCl BY Q - Absorption ratio method in synthetic mixture

A simple, accurate, precise and economical Q- Absorption Ratio spectrophotometric method was developed and validated for estimation of Anagliptin and Metformin HCl in synthetic mixture. Anagliptin and Metformin HCl showed an iso-absorptive point at 238 nm in distilled water. The second wavelength used was 233 nm which is λ_max of Metformin HCl in distilled water. The concentration of the drugs was determined by using ratio of absorbance at iso-absorptive point (λ₁ = 238 nm) and at the λ_max of Metformin HCl (λ₂ = 233 nm). This method is linear for both drugs; in range of 2–12 μg/mL at λ₁ (R² = 0.999) and at λ₂ (R² = 0.9998) for Anagliptin, and in the range of 5–30 μg/mL for Metformin HCl found at λ₁ (R² = 0.9995) and at λ₂ (R² = 0.9997). The % Recovery was 100.42–101.83 % of Anagliptin and 99.94–101.63 % of Metformin HCl by standard addition method. The LOD was found to be 0.201 μg/mL and 0.262 μg/mL for Anagliptin at λ₁ and λ₂ respectively. The LOD was found to be 0.320 μg/mL and 0.167 μg/mL for Metformin HCl at λ₁ and λ₂ respectively. The LOQ was found to be 0.610 μg/mL and 0.794 μg/mL for Anagliptin at λ₁ and λ₂ respectively. The LOQ was found to be 0.972 μg/mL and 0.506 μg/mL for Metformin HCl at λ₁ and λ₂ respectively. The method was found to be precise as % RSD was less than 2.00 in Repeatability, Interday and Intraday precision for Anagliptin and Metformin HCl. The % assay of analyte drugs in synthetic mixture was found to be 100.601% of Anagliptin and 100.206 % of Metformin HCl which showed good applicability of the developed method.

Pharmaceutical analysis combined with in-silico therapeutic and toxicological profiling on zileuton and its impurities to assist in modern drug discovery

The obligatory testing of drug molecules and their impurities to protect users against toxic compounds seems to provide interesting opportunities for new drug discovery. Impurities, which proved to be non-toxic, may be explored for their own therapeutic potential and thus be a part of future drug discovery. The essential role of pharmaceutical analysis can thus be extended to achieve this purpose. The present study examined these objectives by characterizing the major degradation products of zileuton (ZLT), a 5-lipoxygenase (5-LOX) inhibitor being prevalently used to treat asthma. The drug sample was exposed to forced degradation and found susceptible to hydrolysis and oxidative stress. The obtained Forced Degradation Products (FDP's) were resolved using an earlier developed and validated Ultra-High-Pressure Liquid Chromatography Photo-Diode-Array (UHPLC-PDA) protocol. ZLT, along with acid-and alkali-stressed samples, were subjected to Liquid-chromatography Mass-spectrometry Quadrupole Time-of-flight (LC/MS-QTOF) studies. Major degradation products were isolated using Preparative TLC and characterized using Q-TOF and/or Proton nuclear magnetic resonance (¹HNMR) studies. The information obtained was assembled for structural conformation. Toxicity Prediction using Komputer Assisted Technology (TOPKAT) toxicity analyses indicated some FDP's as non-toxic when compared to ZLT. Hence, these non-toxic impurities may have bio-affinity and can be explored to interact with other therapeutic targets, to assist in drug discovery. The drug molecule and the characterized FDP's were subjected to 3-Dimensional Extra Precision (3D-XP)-molecular docking to explore changes in bio-affinity for the 5-LOX enzyme (PDB Id: 3V99). One FDP was found to have a higher binding affinity than the drug itself, indicating it may be a suitable antiasthmatic. The possibility of being active at other sites cannot be neglected and this is evaluated to a reasonable extent by Prediction of Activity Spectra for Substances (PASS). Besides being antiasthmatic, some FDP's were predicted antineoplastic, antiallergic and inhibitors of Complement Factor-D.

Identification and characterization of unknown degradation impurities in beclomethasone dipropionate cream formulation using HPLC, ESI-MS and NMR

The present study focuses on identifying the degradation profile and pathways of unknown impurities from beclomethasone dipropionate (BDP) topical cream formulation reported under accelerated stability conditions. Six degradation impurities were observed during the accelerated stability testing of BDP topical cream formulation, and these thermally labile degradation impurities were primarily identified using a simple, effective and mass compatible isocratic reversed-phase high-performance liquid chromatography with ultraviolet detection method. The degradation impurities found in this sample were of very low concentration levels, thus the concentration of these impurities in the sample was enriched by mimicking the thermal degradation conditions to structurally elucidate the unknown impurities. These BDP thermal degradation impurities were isolated using preparative liquid chromatography and followed by pre-concentration using rota-vapour. Further, the collected thermal degradation impurities were characterized using ESI-MS, and the major impurity was identified using ¹H and C¹³ NMR spectroscopy, and DEPT technique. Plausible degradation pathway and mechanism of each impurity from BDP has been proposed based on the obtained mass and NMR spectral data. Thus, the present method is simple and suitable to be applied towards BDP assay in various formulations, and also to investigate the thermal stability and degradation kinetics of the final drug product.

Determination of progesterone compounds in the crude methanol extract of benalu duku leaves

Background and Aim:

Dendrophthoepentandra L. Miq (benalu duku) is a parasitic herb that commonly grows on the host plant Lansium domesticum. Researchers have found that the plant contains anticancer compounds and may contain phytoandrogens, including progesterone-like compounds, in its crude methanol extract. The objective of the current study was to investigate the compound of phyto progesterone in benalu duku leaves after extracted by methanol and prepared using an analytical column of high-performance liquid chromatography (HPLC).

Materials and Methods:

About 400 g of benalu duku leaves were pulverized, and their compounds were isolated by the isocratic method using an RP-18 analytical column (5 µm) with a mobile phase of 70:30 (methanol: water) in a photodiode array detector adjusted to 254 nm. The phyto progesterone compound was identified at a retention time of approximately 6.01 min.

Results:

By LC-electrospray ionization mass spectrometry focusing on molecular fractions, the fingerprint area of the Fourier transform-infrared spectroscopy (FT-IR, cm⁻¹) and ^Hnuclear magnetic resonance (NMR) spectra indicated that the phyto progesterone product isolated was identical to the certified reference material of pure progesterone, particularly the specific functional groups in the FT-IR spectrum at wavenumbers of 1317.43 cm⁻¹ and 1386.86 cm⁻¹ and in the proton ^HNMR spectrum at carbon 21 of progesterone (p<0.05).

Conclusion:

Each 49.888 µg/mL of crude benalu duku leaf extract dissolved in the mobile phase contained 28.515±0.713 µg/mL phyto progesterone.