Identification, isolation, and structural characterization of novel forced degradation products of Ertugliflozin using advanced analytical techniques.

The research elucidates the stress degradation behavior of Ertugliflozin, which is used for the treatment of type-2 diabetics. The degradation was conducted as per ICH guidelines and Ertugliflozin is relatively stable in thermal, photolytic, neutral, and alkaline hydrolysis conditions; however, considerable degradation was detected in acid hydrolysis and oxidative hydrolysis. Degradation products were identified by ultra-high-performance liquid chromatography-mass spectrometry, isolated by semi-preparative high-performance liquid chromatography, and structural characterization using high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy. Total four degradation products were identified and isolated in acid degradation, which are degradation products 1, 2, 3, and 4. Whereas in oxidative conditions, degradation product 5 was identified. All the five degradation products formed are novel, which was not reported earlier. This is the first time documented complete structural characterization of all five degradation products by using a hyphenated analytical technique. High-resolution mass, and nuclear magnetic resonance spectroscopy were used in the present study to get concrete confirmation of degradation products structures. The current method is also used to identify degradation products with shorter runtime in the future.

Degradants of Tenofovir Disoproxil Fumarate Under Forced Yet Mild Thermal Stress: Isolation, Comprehensive Structural Elucidation, and Mechanism.

In addition to understanding the mechanism of action for a specific drug candidate, information regarding degradation pathways/products under various stress conditions is essential to know about their short- and long-term effects on health and environment. In line with that, tenofovir disoproxil fumarate (TDF, a co-crystal form of the prodrug tenofovir with fumaric acid), particularly used as an antiretroviral drug for treatment of HIV and hepatitis-B among others, is subjected to primarily thermal and other ICH-prescribed forced degradation conditions and their various degradation products are identified. Upon thermal degradation at 60°C for 8 h, five different degradants (namely DP-1 to DP-5) are isolated, and their structures are unambiguously confirmed using advanced analytical and spectroscopic techniques including ultra-performance liquid chromatography-mass spectrometry (UPLC-MS), high-resolution mass spectrometry (HRMS), state-of-the-art 1- and 2-dimensional nuclear magnetic resonance (1D and 2D NMR), and Fourier-transform infrared spectroscopic (FT-IR) techniques. Among fully characterized five degradants, two new degradants (DP-2 and DP-4) are identified which can potentially impact the stability of TDF via different pathways. Plausible mechanisms leading to all five thermal degradation products are also proposed including the generation of carcinogenic formaldehyde for some cases. The present systematic structural study especially combining MS and advanced NMR investigations unequivocally confirms the structures of the degradants and opens opportunities for connecting the various degradation pathways especially for the TDF-related pharmaceutical candidates.

Isolation and structural characterization of two novel oxidative degradation products of losartan potassium active pharmaceutical ingredient using advanced analytical techniques.

RATIONALE: Losartan potassium (losartan) is the most frequently utilized antihypertensive medication in the world. However, partial oxidation of losartan produces toxic by-products that could be harmful to living organisms. Therefore, it is necessary to degrade the losartan and identify the potential toxic oxidative degradation products to minimize their formation during manufacturing, formulation, storage, and packing conditions. METHODS: Oxidative degradation experiments of losartan were performed according to ICH guidelines. The degradation products were detected using ultra-high-performance liquid chromatography-mass spectrometry analysis, isolated by using preparative HPLC, and identified by using high-resolution mass spectrometry and nuclear magnetic resonance spectroscopic techniques. RESULTS: The degradation products (DP-1, DP-2, and DP-3) were identified as (((2'-(2H-tetrazol-5-yl)-[1,1'-biphenyl]-4-yl)methyl)amino)-2-oxoethylpentanoate, 5-(4'-((2 butyl-4-chloro-5-(hydroxymethyl)-1H-imidazol-1-yl)methyl)-[1,1'-biphenyl]-2-yl)-1H tetrazol-1-ol, and 5-(4'-((2-butyl-4-chloro-5-(hydroxymethyl)-1H-imidazol-1 yl)methyl)-[1,1'-biphenyl]-2-yl)-2H-tetrazol-2-ol, respectively. CONCLUSIONS: Forced degradation of losartan potassium API under oxidative condition indicates the formation of two major novel oxidative degradation products (DP-2 and DP-3) and one minor known degradation product (DP-1).Preparative HPLC used for the isolation of the resultant DPs and their structures were successfully established using UHPLC-MS, 1H NMR, 13C NMR, HSQC, HMBC, and HRMS spectroscopic techniques.

Serum and urine metabolomics analysis reveals the role of altered metabolites in patulin-induced nephrotoxicity.

Various studies have identified the kidney as a target organ for patulin (PAT)-induced toxicity. However, detailed mechanistic insights into PAT-induced nephrotoxicity had not yet been done. Therefore, along with classical toxicological parameters, liquid chromatography-high resolution massed spectrometry (LC-HRMS) based metabolomics has been carried out to delineate the mechanism(s) of PAT-induced nephrotoxicity.An in vivo study was conducted using male Wistar rats, divided into three groups. PAT (25 µg/kg b.wt and 100 µg/kg b.wt) and, control were given through oral gavage, 5 days/week for 28 days. At the end of the experiment, changes in the mean body/ organ weight, food and water intake, expression of marker proteins of kidney injury, and histopathological changes were investigated. Furthermore, using LC-HRMS based metabolomics was performed on the serum and urine of PAT-exposed rats. The histopathological and toxicological analysis revealed a significant increase in glomerular mesangial cells, vacuolar degeneration, and cast deposition in the proximal convoluted tubules. The metabolomics showed metabolic perturbations in amino and fatty acid-related metabolic pathways in serum and urine of PAT-treated rats. In conclusion this study expands our understanding of PAT-induced metabolic alterations and its effects on renal function.

Oxidative degradation profile studies of tavaborole by a validated stability indicating RP-UPLC method: Isolation and characterization of novel degradant using 2D-NMR and HRMS.

The current research work reports a study on the degradation profile of tavaborole, which is an oxaborole antifungal drug used to treat infections in the toenails. This work also reports the chemical stability of tavaborole in different stress conditions along with the isolation and characterization of degradation products by high-resolution mass spectrometry and two-dimensional nuclear magnetic resonance techniques. A sensitive and reproducible stability-indicating ultra-performance liquid chromatography method was developed and validated for quantification of tavaborole bulk drug in the presence of degradation products. Significant degradation was observed during oxidative stress conditions using H2 O2 . It was observed that the drug was highly unstable under oxidation stress conditions and thus degradation profiles with various oxidizing reagents were studied. One unknown impurity (DP-1) was formed during peroxide degradation, which was isolated by reverse-phase preparative chromatography. The structure of this degradant was characterized by high-resolution mass spectrometry and multidimensional nuclear magnetic resonance techniques. The structure of this novel impurity DP-1 was identified as [4-fluoro-2-(hydroxymethyl)phenol], which was not reported as a degradant in the literature. An Acquity BEH C18 , 100 × 2.1 mm, 1.7 µm column was used to achieve the desired separation within a shorter runtime of 4.0 min. The method was validated for specificity, precision, linearity and accuracy over the concentration range of 5.0-400 µg ml-1 (r2 -0.9999) and limit of quantitation 5.0 µg ml-1 . This method is compatible with LCMS analysis which enables to identify the unknown impurities formed in the process.

Development of a multiclass method to quantify phthalates, pharmaceuticals, and personal care products in river water using ultra-high performance liquid chromatography coupled with quadrupole hybrid Orbitrap mass spectrometry.

Rationale: The organic micropollutants such as phthalates, pharmaceuticals, and personal care products (PPPCPs) enter the surface water through various routes. The aim of this study is to develop a sensitive and efficient method to identify and quantify 26 PPPCPs found in river water with acceptable accuracy and precision using a liquid chromatograph hyphenated with quadrupole hybrid Orbitrap mass spectrometry (Q-Orbitrap-MS) in a single chromatographic run. Method: The organic micropollutants were extracted from river water by solid-phase extraction (SPE) using hydrophilic-lipophilic balance sorbent and analyzed using an ultra-high performance liquid chromatograph (UHPLC) equipped with C18 stationary phase for chromatographic separation. The targeted mass experiments were conducted in a Q-Orbitrap-MS system in positive and negative electrospray ionization mode. Results: The method was found to be linear in the concentration range of 1-125 ng/L with coefficient of determination lying in the range of 0.995-0.999. The method achieved limit of quantification in the range of 0.41-1.72 ng/L, and method recovery measured at three different concentrations was found to be in the range of 75-115%. Intra- and interday precision expressed as percent relative standard deviation was found to be <15%. Matrix effect was found to be in the range of 83.5-109.79%. The matrix match calibration was used for quantification of PPPCPs in river water sample. The method performance was evaluated by analyzing real samples collected from Ganga River, and the concentrations of 21 analytes were found to be in the range of 0.76-9.49 ng/L for pharmaceuticals, 1.49-8.67 ng/L for phthalates, and 0.9-7.58 ng/L for personal care products. Conclusions: The present method was found to be precise, sensitive, and rapid to determine 26 PPPCPs including phthalates in river water samples using SPE-UHPLC-Q-Orbitrap-MS.

Separation of Unprecedented Degradants of Domperidone by Ultra-Performance Convergence Chromatography and Their Structure Elucidation.

Domperidone, a gastroprokinetic agent, is a common drug to treat emesis. It was subjected to acid, base-mediated hydrolysis, peroxide-mediated oxidation, photolysis and thermal degradation according to ICH guidelines to observe stability of the selected drug under the stress conditions. Although the drug is resistant to base hydrolysis, photolysis and thermal stressors, two degradants (DP-ISO1 and DP-ISO2) were formed in acid mediated hydrolysis. Oxidation with hydrogen peroxide also resulted in one product (DP-OX). All three degradants were isolated from the crude reaction mixture by preparative high-performance liquid chromatography and supercritical fluid chromatography. Structures of isolated compounds were unambiguously characterized as 5-chloro-1-(1-(3-(6-chloro-2-oxo-2,3-dihydro-1H-benzo[d]imidazol-1-yl)propyl)piperidin-4-yl)-1,3-dihydro-2H-benzo[d]imidazol-2-one (DP-ISO1), 5-chloro-1-(3-(4-(5-chloro-2-oxo-2,3-dihydro-1H-benzo[d]imidazol-1-yl)piperidin-1-yl)propyl)-1,3-dihydro-2H-benzo[d]imidazol-2-one (DP-ISO2), 4-(5-chloro-2-oxo-2,3-dihydro-1H-benzo[d]imidazol-1-yl)-1-(3-(2-oxo-2,3-dihydro-1H-benzo[d]imidazol-1-yl)propyl)piperidine 1-oxide (DP-OX) by analysis of mass spectrometry, 1D and 2D nuclear magnetic resonance spectra. To the best of our knowledge, DP-ISO1 and DP-ISO2 are new and DP-OX was previously reported as domperidone impurity.

Identification, isolation and characterization of dolutegravir forced degradation products and their cytotoxicity potential.

Dolutegravir was approved by USFDA, Canada and European regulatory authorities as antiretroviral medication. In this article, DLG forced degradation studies as per the International Council for Harmonization (ICH) prescribed stress conditions was conducted and the resulting degradants were fully characterized. DLG was stable in basic, thermal and photolytic stress conditions, whereas DLG was found to unstable in acidic and oxidative conditions. One degradant each from acid and peroxide treated solutions was resolved on LC-MS and labelled as DP-1 and DP-2 with RT 1.80 min and 1.41 min, respectively. DP-1 and DP-2 were isolated by preparative HPLC with C18 column using gradient elution method. Subsequently DP-1 and DP-2 peaks were subjected to HRMS for accurate mass. Molecular mass of DP-1 and DP-2 were m/z 420.1379 (positive mode) and m/z 214.0319 (negative mode), respectively. Further, DP-1 & DP-2 were subjected to NMR spectroscopic analysis (including 2D) for structural confirmation. DP-1 was identified as N-(2,4-difluorobenzyl)-9-hydroxy-2-(4-hydroxybutan-2-yl)-1,8-dioxo-2,8-dihydro-1H-pyrido[1,2-a]pyrazine-7-carboxamide and it is earlier reported by Gudisela et al. [19] as DLG process impurity. DP-2 was identified as 2-(2,4difluorobenzylamino)-2-oxoacetic acid which is novel DLG degradant and not reported earlier to the best of our knowledge. DLG along its forced degradation products were found to be non-cytotoxic in in vitro assay conditions using HepG2 cells.

Degradation studies of Ibrutinib under stress conditions: Characterisation and structural elucidation of novel degradants.

The aim of the research work is to study the degradation behaviour of Ibrutinib (IBN) which is performed under different stress conditions according to International Conference on Harmonization guidelines (ICH). The study included monitoring degradation of the Ibrutinib drug under acidic, base, oxidation, thermal and photolytic conditions followed by isolation and characterisation of degradation products (DP) by Liquid Chromatography Mass Spectrometry (LCMS), High resolution Mass Spectrometry (HR-MS/MS) and Nuclear Magnetic Resonance (NMR) studies. The IBN drug is stable under oxidation, thermal and photolytic conditions. The degradation of drug is observed under acidic and basic conditions. Two novel degradation products are formed which are not reported in the literature. The LCMS method has been developed for chromatographic separation of drug and its degradation products which were attained on C18 BEH UPLC column (50 mm X 2.1 mm, 1.7 µm). The combination of 0.05% Acetonitrile in water and 0.05% Formic acid in water are used as a mobile phase. The flow rate is 0.6 ml/min and UV wavelength monitored at 215 nm. Acetonitrile and water are used as diluents.

Structure elucidation of novel degradation products of thiocolchicoside by NMR spectroscopy.

Thiocolchicoside is a natural product analogue often used for its spasmolytic action. To know more about its stability under various stress conditions, the drug was stirred in acid, base and peroxide solutions. In acid hydrolysis, two products were obtained and in both, the glucose got cleaved. In one of them the acetyl group also got cleaved. A set of two diastereomers were formed during the peroxide mediated hydrolysis. The base mediated hydrolysis resulted in formation of three novel degradants. They have six membered rings in their structures instead of a seven membered cycloheptatrienone. Structures of known and novel degradation products have been elucidated by extensive analysis of HRMS, 1D and 2D NMR spectroscopic techniques.

Degradation study of irbesartan: Isolation and structural elucidation of novel degradants.

To assess the stability of Irbesartan under stress conditions, and identify the degradation products, it was subjected to hydrolytic and oxidative stress, according to ICH guideline Q1A (R2). The drug showed degradation only in basic conditions, while it was stable to other stress conditions. Three degradation products were formed, which were separated on a C-8 column employing prep HPLC using gradient elution. The structures were established by extensive 1D and 2D NMR spectroscopic studies and mass spectra. The products were identified as (2'-(2H-tetrazol-5-yl)-[1,1'-biphenyl]-4-yl)methanamine (DP-1), N-((2'-(2H-tetrazol-5-yl)-[1,1'-biphenyl]-4-yl)methyl)pentanamide (DP-2) and N-((2'-(2H-tetrazol-5-yl)-[1,1'-biphenyl]-4-yl)methyl)-1-pentanamidocyclopentane-1-carboxamide (DP-3). One of the three, DP-1, was reported earlier. However, its structure has not been elucidated by NMR. The other two degradants are novel and are being reported here for the first time.

Cladribine Analogues via O6-(Benzotriazolyl) Derivatives of Guanine Nucleosides.

Cladribine, 2-chloro-2'-deoxyadenosine, is a highly efficacious, clinically used nucleoside for the treatment of hairy cell leukemia. It is also being evaluated against other lymphoid malignancies and has been a molecule of interest for well over half a century. In continuation of our interest in the amide bond-activation in purine nucleosides via the use of (benzotriazol-1yl-oxy)tris(dimethylamino)phosphonium hexafluorophosphate, we have evaluated the use of O6-(benzotriazol-1-yl)-2'-deoxyguanosine as a potential precursor to cladribine and its analogues. These compounds, after appropriate deprotection, were assessed for their biological activities, and the data are presented herein. Against hairy cell leukemia (HCL), T-cell lymphoma (TCL) and chronic lymphocytic leukemia (CLL), cladribine was the most active against all. The bromo analogue of cladribine showed comparable activity to the ribose analogue of cladribine against HCL, but was more active against TCL and CLL. The bromo ribose analogue of cladribine showed activity, but was the least active among the C6-NH2-containing compounds. Substitution with alkyl groups at the exocyclic amino group appears detrimental to activity, and only the C6 piperidinyl cladribine analogue demonstrated any activity. Against adenocarcinoma MDA-MB-231 cells, cladribine and its ribose analogue were most active.