液相色谱-飞行时间质谱、液相色谱-串联质谱和核磁共振用于右旋兰索拉唑的强制降解研究和氧化降解产物的结构表征(英文)

The present study deals with the forced degradation behavior of dexlansoprazole under International Conference on Harmonisation(ICH)prescribed stress conditions. The drug was found to be more labile under acid,base,neutral,oxidative hydrolysis and thermal stress,while it was moderately stable under photolytic conditions. The known and unknown degradation products were separated on a C-18 column using a stabilityindicating method. Liquid chromatography-mass spectrometry(LC-MS)analysis was performed for all the degradation studies. Isolation and structure characterization of oxidation degradation products were executed using sophisticated tools,viz. preparative high performance liquid chromatography(HPLC),liquid chromatographymass spectrometry / time of flight(LC-MS / TOF),liquid chromatography-tandem mass spectrometry(LC-MS /MS),and nuclear magnetic resonance(NMR). This study demonstrates an ample methodology of degradation studies and structure elucidation of unknown degradation products of dexlansoprazole,which helps in the development and stability study of active pharmaceutical ingredients and formulated products.     

Study of the forced degradation behavior of prasugrel hydrochloride by liquid chromatography with mass spectrometry and liquid chromatography with NMR detection and prediction of the toxicity of the characterized degradation products

Prasugrel was subjected to forced degradation studies under conditions of hydrolysis (acid, base, and neutral), photolysis, oxidation, and thermal stress. The drug showed liability in hydrolytic as well as oxidative conditions, resulting in a total of four degradation products. In order to characterize the latter, initially mass fragmentation pathway of the drug was established with the help of mass spectrometry/time‐of‐flight, multiple stage mass spectrometry and hydrogen/deuterium exchange data. The degradation products were then separated on a C₁₈ column using a stability‐indicating volatile buffer method, which was later extended to liquid chromatography‐mass spectrometry studies. The latter highlighted that three degradation products had the same molecular mass, while one was different. To characterize all, their mass fragmentation pathways were established in the same manner as the drug. Subsequently, liquid chromatography‐nuclear magnetic resonance (NMR) spectroscopy data were collected. Proton and correlation liquid chromatography with NMR spectroscopy studies highlighted existence of diastereomeric behavior in one pair of degradation products. Lastly, toxicity prediction by computer‐assisted technology (TOPKAT) and deductive estimation of risk from existing knowledge (DEREK) software were employed to assess in silico toxicity of the characterized degradation products.     

Screening of nitrogen mustards and their degradation products in water and decontamination solution by liquid chromatography-mass spectrometry

Analysing nitrogen mustards and their degradation products in decontamination emulsions posed a significant challenge due to the different phases present in such matrices. Extensive sample preparation may be required to isolate target analytes. Furthermore, numerous reaction products are formed in the decontamination emulsion. A fast and effective qualitative screening procedure was developed for these compounds, using liquid chromatography-mass spectrometry (LC-MS). This eliminated the need for additional sample handling and derivatisation that are required for gas chromatographic-mass spectrometric (GC-MS) analysis. A liquid chromatograph with mixed mode column and isocratic elution gave good chromatography. The feasibility of applying this technique for detecting these compounds in spiked water and decontamination emulsion was demonstrated. Detailed characterisation of the degradation products in these two matrices was carried out. The results demonstrated that N-methyldiethanolamine (MDEA), N-ethyldiethanolamine (EDEA) and triethanolamine (TEA) are not the major degradation products of their respective nitrogen mustards. Degradation profiles of nitrogen mustards in water were also established. In verification analysis, it is important not only to develop methods for the identification of the actual chemical agents; the methods must also encompass degradation products of the chemical agents as well so as to exclude false negatives. This study demonstrated the increasingly pivotal role that LC-MS play in verification analysis.     

Discerning the stability behaviour of mavacamten availing liquid chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy: In silico toxicity and mutagenicity prediction of degradation products

The present study aimed to separate, identify, and characterise the degradation products formed when mavacamten is exposed to stress degradation as well as the stability of the drug in various environments and also to understand its degradation chemistry. Prediction of in silico toxicity and mutagenicity was aimed at the observed degradation products. Stress degradation along with stability studies and degradation kinetics were performed on mavacamten, and separation of degradation products was carried out by high-performance liquid chromatography. Tandem mass spectrometry studies were executed to characterise the structures of degradation products using product ion fragments. Orthogonally, nuclear magnetic resonance experiments were conducted to elucidate the structures having ambiguity in characterising them. Deductive Estimation of Risk from Existing Knowledge and Structure Activity Relationship Analysis using Hypotheses software were used to establish in silico toxicity and mutagenic profiles of mavacamten and its degradation products. Two degradation products of mavacamten found in acidic hydrolytic stress conditions were separated, identified, characterised, and proposed as 1-isopropylpyrimidine-2,4,6(1H,3H,5H)-trione and 1-phenylethanamine. Mavacamten was found to be stable under different pH and gastrointestinal conditions. The degradation kinetics of mavacamten under 1 N acidic condition followed zero-order kinetics, and it was degraded completely within 6 h. In silico toxicity and mutagenicity studies revealed that 1-phenylethanamine can be a skin sensitiser. A high-performance liquid chromatography method was developed for the separation of degradation products of mavacamten and characterised by liquid chromatography–tandem mass spectrometry and nuclear magnetic resonance. During the manufacturing and storage of drug product, precautions need to be taken when dealing with acidic solutions as the drug is prone to hydrolysis in acidic conditions. The formation of 1-phenylethanamine under these conditions is to be monitored as it is a skin sensitiser.     

Ultrapure water for liquid chromatography-mass spectrometry studies

Improvements in trace enrichment techniques combined with the sensitivity of mass spectrometry offer enhanced opportunities to analyze ever lower concentrations of drugs, metabolites, pesticides or environmental pollutants. To perform HPLC and liquid chromatography-mass spectrometry (LC-MS) analyses under optimum conditions, the water used for mobile phase preparation needs to be highly purified and delivered on demand. Indeed, both UV photodiode array detection and MS detection methods are sensitive to organic contaminants (total organic carbon, TOC), and the water quality has a direct impact on the achievable detection limits. The benefits of UV photooxidation on TOC reduction for LC-MS studies were highlighted using electrospray ionization MS detection by comparing HPLC-grade bottled water, freshly produced UV185/254-treated water, and freshly produced non-UV-treated water.     

Selective separation and characterization of the stress degradation products of ondansetron hydrochloride by liquid chromatography with quadrupole time‐of‐flight mass spectrometry

Ondansetron hydrochloride was subjected to forced degradation studies under various conditions of hydrolysis (acidic, basic, and neutral), oxidation, photolysis, and thermal as prescribed by International Conference on Harmonisation guideline Q1A (R2). A simple, selective, precise, and accurate high‐performance liquid chromatography method was developed on a Waters Xterra C₁₈ (150 × 4.6 mm id, 3.5 μm) column using 10 mM ammonium formate (pH 3.0)/methanol as a mobile phase in gradient elution mode at a flow rate of 0.6 mL/min. The method was extended to liquid chromatography quadrupole time‐of‐flight tandem mass spectrometry for identification and structural characterization of stress degradation products of ondansetron. The drug showed significant degradation in base hydrolytic and photolytic stress conditions in the liquid state, while it was found to be stable in neutral, acidic, thermal, and oxidative stress conditions. A total of five degradation products were characterized and most probable mechanisms for the formation of degradation products have been proposed on the basis of a comparison of the fragmentation of the [M + H]⁺ ions of the drug and its degradation products. Finally, the developed method was validated in terms of specificity, linearity, accuracy, precision, and robustness as per International Conference on Harmonisation guideline Q2 (R1).     

Identification and characterization of stressed degradation products of metoprolol using LC/Q-TOF-ESI-MS/MS and MS(n) experiments

A rapid, specific and reliable isocratic high-performance liquid chromatography combined with quadrupole time-of-flight electrospray ionization tandem mass spectrometry (LC/Q-TOF-ESI-MS/MS) method has been developed and validated for the identification and characterization of stressed degradation products of metoprolol. Metoprolol, an anti-hypertensive drug, was subjected to hydrolysis (acidic, alkaline and neutral), oxidation, photolysis and thermal stress, as per ICH-specified conditions. The drug showed extensive degradation under oxidative and hydrolysis (acid and base) stress conditions. However, it was stable to thermal, neutral and photolysis stress conditions. A total of 14 degradation products were observed and the chromatographic separation of the drug and its degradation products was achieved on a C(18) column (4.6 × 250 mm, 5 μm). To characterize degradation products, initially the mass spectral fragmentation pathway of the drug was established with the help of MS/MS, MS(n) and accurate mass measurements. Similarly, fragmentation pattern and accurate masses of the degradation products were established by subjecting them to LC-MS/QTOF analysis. Structure elucidation of degradation products was achieved by comparing their fragmentation pattern with that of the drug. The degradation products DP(2) (m/z 153) and DP(14) (m/z 236) were matched with impurity B, listed in European Pharmacopoeia and British Pharmacopoeia, and impurity I, respectively. The LC-MS method was validated with respect to specificity, linearity, accuracy and precision.     

Application of liquid chromatography with mass spectrometry combined with photodiode array detection and tandem mass spectrometry for monitoring pesticides in surface waters

Liquid chromatography with photodiode array detection (LC-DAD) and liquid chromatography with mass spectrometry (LC-MS) are two techniques that have been widely used in monitoring pesticides and their degradation products in the environment. However, the application of liquid chromatography with tandem mass spectrometry (LC-MS-MS) for such purposes, once considered too costly, is now gaining considerable ground. In this study, we compare these methods for the multi-residue analysis of pesticides in surface waters collected from the central and southeastern regions of France, and from the St. Lawrence River in Canada. Forty-eight pesticides belonging to eight different classes (triazine, amide, phenylurea, triazole, triazinone, benzimidazole, morpholine, phenoxyalkanoic), along with some of their degradation products, were monitored on a regular basis in the surface waters. For LC-MS, we used the electrospray ionization (ESI) interface in the negative ionization mode on acidic pesticides (phenoxyalkanoic, sulfonylurea), and the atmospheric pressure chemical ionization (APCI) interface in the positive ionization mode on the remaining chemicals. Different extraction techniques were employed, including liquid-liquid extraction with dichloromethane, and solid-phase extraction using C18-bonded silica and graphitized carbon black cartridges. Eleven of the target chemicals (desethylatrazine, desisopropylatrazine, atrazine, simazine, terbuthylazine, metolachlor, carbendazime, bentazone, penconazole, diuron and isoproturon) were detected by LC-MS at concentrations ranging from 20 to 900 ng/l in the surface waters from France, and six pesticides (atrazine, desethylatrazine, desisopropylatrazine, cyanazine, simazine and metolachlor) were detected by LC-MS and LC-MS-MS at concentrations ranging from 3 to 52 ng/l in the samples drawn from the St. Lawrence River. There was good correlation between the LC-DAD and LC-MS techniques for 60 samples. The slope of the curves expressing the relationship between the results obtained with LC-DAD versus those obtained by LC-MS was near 1, with a correlation coefficient (r) of over 0.93. The identification potential of the LC-MS technique, however, was greater than that of the LC-DAD; its mass spectra, mainly reflecting the pseudomolecular ion resulting from a protonation or a deprotonation of the molecule, was rich in information. The LC-MS-MS technique with ion trap detectors, tested against the LC-MS on 10 surface water samples, gave results that correlated well with the LC-MS results, albeit generating mass spectra that yielded far more information about the structure of unknown substances. The sensitivity of the LC-MS-MS was equivalent to the selected ion monitoring (SIM) acquisition mode in LC-MS. The detection limits of the target pesticides ranged from 20 to 100 ng/l for the LC-MS technique (under full scan acquisition), and from 2 to 6 ng/l for LC-MS-MS. These limits were improved by a factor of almost 10 by increasing the sample volume to 10 l.     

Enhanced monitoring of biopharmaceutical product purity using liquid chromatography-mass spectrometry

LC-MS is a widely used technique for impurity detection and identification. It is very informative and generates huge amounts of data. However, the relevant chemical information may not be directly accessible from the raw data map, particularly in reference to applications where unknown impurities are to be detected. This study demonstrates that multivariate statistical process control (MSPC) based on principal component analysis (PCA) in conjunction with multiple testing is very powerful for comprehensive monitoring and detection of an unknown and co-eluting impurity measured with liquid chromatography-mass spectrometry (LC-MS). It is demonstrated how a spiked impurity present at low concentrations (0.05% (w/w)) is detected and further how the contribution plot provides clear diagnostics of the unknown impurity. This tool makes a fully automatic monitoring of LC-MS data possible, where only relevant areas in the LC-MS data are highlighted for further interpretation.     

Characterization of stress degradation products of amodiaquine dihydrochloride by liquid chromatography with high‐resolution mass spectrometry and prediction of their properties by using ADMET Predictor™

The degradation behavior of amodiaquine dihydrochloride, an antimalarial drug, was investigated in solution as well as solid states. The drug was subjected to hydrolytic, photolytic, oxidative, and thermal stress conditions, according to International Conference on Harmonization guideline Q1A(R2). It showed extensive hydrolysis in acidic, alkaline, and neutral solutions both with and without light, while it proved to be stable to thermal and oxidative conditions. In total, six degradation products were formed, which were separated on a C8 column, employing a gradient reversed‐phase high‐performance liquid chromatography method in which acetonitrile and 10 mM ammonium formate (pH 3.0) were used in the mobile phase. To characterize the degradation products, mass fragmentation behavior of the drug was established by direct infusion of solution to quadrupole time‐of‐flight and multiple‐stage mass spectrometry systems. Liquid chromatography with high‐resolution mass spectrometry studies were subsequently carried out on the stressed samples using the same gradient high‐performance liquid chromatography method employed for the separation of the degradation products. Hydrogen/deuterium exchange studies were additionally conducted to determine the number of labile hydrogen atoms. The degradation pathway of the drug was delineated, justified by mechanistic explanation. Lastly, ADMET Predictor™ software was employed to predict relevant physicochemical and toxicity data for the degradation products.     

Investigations on the degradation of aspartame using high-performance liquid chromatography/tandem mass spectrometry

Aspartame is a widely used sweetener,the long-term safety of which has been controversial ever since it was accepted for human consumption.It is unstable and can produce some harmful degradation products under certain storage conditions.A high-performance liquid chromatography/tandem mass spectrometry method was developed for the simultaneous analysis of aspartame and its four degradation products,including aspartic acid,phenylalanine,aspartyl-phenylalanine and 5-benzyl-3,6-dioxo-2-piperazieacetic acid in water and in diet soft drinks.Aspartame and its four degradation products were quantified by a matrix matched external standard calibration curve with excellent correlation coefficients.The limits of detection were 0.16–5.8 mg/L,which exhibited higher sensitivity than common methods.This method was rapid,sensitive,specific and capable of eliminating matrix interferences.It was also applied to the study of the degradation of aspartame at various pH and temperatures.The results indicated that aspartame was partly degraded under strong acidic or basic conditions and the extent of degradation increased with increasing temperature.     

Confirmatory and quantitative analysis using experimental design for the extraction and liquid chromatography-UV, liquid chromatography-mass spectrometry and liquid chromatography-mass spectrometry/mass spectrometry determination of quinolones in turkey muscle

The aim of this work is to established methods for determination of quinolones (ciprofloxacin, danofloxacin, enrofloxacin, difloxacin and flumequine), regulated by European Union, and sarafloxacin in turkey muscle. An experimental design has been applied for the optimization of the factors that influence the extraction of quinolones from turkey muscle in order to determine the experimental conditions for their extraction with high recoveries. Liquid chromatography with ultraviolet detection (LC-UV), liquid chromatography-mass spectrometry (LC-MS) and liquid chromatography tandem mass spectrometry (LC-MS/MS) have been used for the simultaneous quantification of quinolones antibiotics in turkey muscle. The proposed methods have been validated according to the Food Drugs Administration guideline and presents the limit of quantification below the maximum residue limits established by the European Union for quinolones in turkey muscle. The methods developed have been applied to quantification of enrofloxacin and its main metabolite ciprofloxacin in samples of turkey muscle obtained from animals treated with enrofloxacin.     

Simultaneous determination of components released from dental composite resins in human saliva by liquid chromatography/multiple-stage ion trap mass spectrometry

Dental composite resins are widely used for fixing teeth; however, the monomers used in dental composite resins have been found to be cytotoxic and genotoxic, namely triethylene glycol dimethacrylate (TEGDMA), urethane dimethacrylate (UDMA), and bisphenol A glycol dimethacrylate (Bis-GMA). In this study, we incubated dental composite resins with human saliva for demonstrating the released monomers and biodegradation products. A simple saliva sample dilution method without purification or derivatization was used for quantification. We found that liquid chromatography coupled with multiple-stage ion trap mass spectrometry (LC-MS(n) ) operated in selected reaction monitoring (SRM) mode was able to separate the three monomers within 10 min. The calibration curves were linear (R2 >0.996) over a wide range for each monomer in saliva: TEGDMA, 5-500 ppb; UDMA, 5-100 ppb, and Bis-GMA, 5-700 ppb. Furthermore, several biodegradation products were discovered with data-dependent MS/MS scan techniques. Although TEGMA degradation products have previously been reported, we identified two previously unknown UDMA degradation products. The LC-MS/MS method developed in this study was able to successfully quantify monomers and their principal biodegradation products from dental composite resins in human saliva.     

Development of analytical methods for multiresidue determination of quinolones in pig muscle samples by liquid chromatography with ultraviolet detection, liquid chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry

This paper presents a comparison between liquid chromatography with ultraviolet detection (LC-UV), liquid chromatography-mass spectrometry (LC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods developed for the multiresidue determination of 8 quinolones, around their maximum residue levels (MRLs) in pig muscle. The procedure involves common extraction of the quinolones from the tissues by traditional extraction, a step for clean-up and preconcentration of the analytes by solid-phase extraction (SPE) and a subsequent liquid chromatographic analysis. The methods present satisfactory results of linearity, precision and limits of quantification much lower than the MRLs established by the European Union for quinolones in pig tissues.     

液相色谱-质谱联用在兴奋剂检测中的应用及进展

液相色谱-质谱联用技术已越来越广泛地应用在兴奋剂的检测中,其中包括对各类小分子兴奋剂和肽类激素等的检测。本文综述了近年来液相色谱-质谱联用在兴奋剂检测中的筛选、确证和定量方面的应用及进展情况,并讨论了相关的检测标准。     

Gas chromatography-mass spectrometry and high-performance liquid chromatographic analyses of thermal degradation products of common plastics.

The thermo-oxidation of five commonly used materials, namely low-density polyethylene, retarded polyethylene, paper with a polyethylene foil, a milk package and filled polypropylene, was studied. Capillary gas chromatography and gas chromatography-mass spectrometry were used to analyze the volatile degradation products, while high-performance liquid chromatography was employed to measure polycyclic aromatic hydrocarbons. The results are discussed from the point of view of toxicity of the products.     

Characterization and origin identification of 2,4,6-trinitrotoluene through its by-product isomers by liquid chromatography-atmospheric pressure chemical ionization mass spectrometry

The by-products of industrial 2,4,6-trinitrotoluene (TNT), including isomers of trinitrotoluene, dinitrotoluene, trinitrobenzene and dinitrobenzene were investigated using liquid chromatography-mass spectrometry (LC-MS), in order to build a profile for the characterization of TNT samples from various origins. LC-MS with atmospheric pressure chemical ionization, in the negative-ion mode, was found to be the most suitable method for this study. The characterization of TNT by the by-product profile was demonstrated on a variety of TNT samples.     

LC-MS/TOF, LC-MSn, on-line H/D exchange and LC-NMR studies on rosuvastatin degradation and in silico determination of toxicity of its degradation products: a comprehensive approach during drug development

The present study dealt with the forced degradation behaviour of rosuvastatin under ICH prescribed stress conditions. The drug was found to be labile under acid hydrolytic and photolytic conditions, while it was stable to base/neutral hydrolytic, oxidative and thermal stress. In total, 11 degradation products were formed, which were separated on a C-18 column using a stability-indicating method. LC-MS analyses indicated that five degradation products had the same molecular mass as that of the drug, while the remaining six had 18 Da less than the drug. Structure elucidation of all the degradation products was executed using sophisticated and modern structural characterization tools, viz. LC-MS/TOF, LC-MSⁿ, on-line H/D exchange and LC-NMR. The degradation pathway and mechanisms of degradation of the drug were delineated. Additionally, in silico toxicity was predicted for all the degradation products using TOPKAT and DEREK software and compared with the drug. This study demonstrates a comprehensive approach of degradation studies during the drug development phase.

Development of generic liquid chromatography-mass spectrometry methods using experimental design

Standard approaches to development of liquid chromatography-mass spectrometry (LC-MS) methods, either ion-pairing or reversed-phase liquid chromatography, have been through trial and error or intentional variation of experimental factors. These approaches to method optimization fail to take into account interactions between experimental factors and therefore the results may not be optimal for the combination of experimental factors. Another approach to optimization is through the use of chemometrics. Chemometric approaches can be more efficient than trial and error or intentional variation because chemometrics make use of multivariate designs; experimental factors are varied simultaneously at the various levels. Therefore chemometrics can take into account interactions between factors. The goal of this study was to develop a generic ion-pair LC-MS method for the analysis of acidic compounds using a chemometric approach called design of experiments (DOE). Four acidic compounds which cover three classes of acidic functional groups: 1-naphthyl phosphate (1), 1-naphthalenesulfonic acid (2), 2-naphthalenesulfonic acid (3), and (1-naphthoxy)acetic acid (4) were used as model compounds to develop the generic method. This study illustrates that LC-MS conditions can be optimized efficiently with minimal amount of experimentation using a chemometric approach to experimental design.     

Determination of ivermectin and transformation products in environmental waters using hollow fibre-supported liquid membrane extraction and liquid chromatography-mass spectrometry/mass spectrometry

A simple and easy-to-use extraction method for aqueous samples based on hollow fibre-supported liquid membrane (HF-SLM) followed by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) was developed to determine ivermectin and transformation products, the monosaccharide (TP1) and the aglycon of ivermectin (TP2). The proposed method attained enrichment factors up to 80, after optimising parameters, such as fibre length, organic solvent, stirring speed, salt level, pH in samples/fibre, extraction time and fibre emptying technique. Method validation with tap and lake water samples provided good linearity and detection limits of 0.2, 1.6 and 0.9 microg/l for ivermectin, TP1 and TP2 in lake water with RSD below 15%.