Characterization of a new component and impurities in josamycin by trap-free two-dimensional liquid chromatography coupled to ion trap time-of-flight mass spectrometry

Two-dimensional liquid chromatography with reversed phase in both dimensions: A review

Two-dimensional liquid chromatography (2D-LC), and in particular comprehensive two-dimensional liquid chromatography (LC×LC), offers increased peak capacity, resolution and selectivity compared to one-dimensional liquid chromatography. It is commonly accepted that the technique produces the best results when the separation mechanisms in the two dimensions are completely orthogonal; however, the use of similar separation mechanisms in both dimensions has been gaining popularity as it helps avoid difficulties related to mobile phase incompatibility and poor column efficiency. The remarkable advantages of using reversed phase in both dimensions (RPLC×RPLC) over other separation mechanisms made it a promising technique in the separation of complex samples. This review discusses some physical and practical considerations in method development for 2D-LC involving the use of RP in both dimensions. In addition, an extensive overview is presented of different applications that relied on RPLC×RPLC and 2D-LC with reversed phase column combinations to separate components of complex samples in different fields including food analysis, natural product analysis, environmental analysis, proteomics, lipidomics and metabolomics.

Separation and structural characterization of unknown impurity in vancomycin by two-dimensional preparative liquid chromatography, LC-MS and NMR

Vancomycin is an effective antibiotic used for the treatment of Gram-positive bacterial infections. During the analysis of vancomycin, an unknown impurity at the level of 0.5% was detected by high-performance liquid chromatography (HPLC). To characterize the structure of the impurity, a new two-dimensional preparative liquid chromatography (2D-Prep-LC) method was developed to separate the impurity from the vancomycin sample. After further analysis including liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance (NMR) spectroscopy, the structure of the unknown impurity was identified as a vancomycin analog in which the N-Methyl-leucine residue on the side chain is replaced by an N-methylmethionine residue. In this study, we established a reliable and efficient method for separating and identifying vancomycin impurities, which will provide a valuable contribution to the field of pharmaceutical analysis and quality control.

An Overview of Advances in the Chromatography of Drugs Impurity Profiling

A systematic literature survey published in several journals of pharmaceutical chemistry and of chromatography used to analyze impurities for most of the drugs that have been reviewed. This article covers the period from 2016 to 2020, in which almost of chromatographic techniques have been used for drug impurity analysis. These chromatography techniques are important in the analysis and description of drug impurities. Moreover, some recent developments in forced impurity profiling have been discussed, such as buffer solutions, mobile phase, columns, elution modes, and detectors are highlighted in drugs used for the study. This primarily focuses on thorough updating of different analytical methods which include hyphenated techniques for detecting and quantifying impurity and degradation levels in various pharmaceutical matrices.

Separation and characterization of two series of unknown degradation impurities caused by light irradiation and autoclaving in xinfujunsu injection using liquid chromatography tandem mass spectrometry

RATIONALE

A series of photodegradation impurities and a series of degradation impurities produced in autoclaving in xinfujunsu injection were discovered, and these unknown impurities were separated and characterized thoroughly using liquid chromatography tandem quadrupole time-of-flight mass spectrometry.

METHODS

The column was a Platisil 5 μm ODS (4.6 × 250 mm, 5 μm). For the analysis of degradation impurities caused by light irradiation and autoclaving, the mobile phase was composed of 0.01 M ammonium formate aqueous solution and acetonitrile/isopropanol (90:10, V/V). Full scan LC-MS and LC-MS² was carried out to obtain as much structural information as possible. The fragmentation behavior of actinomycin D, actinomycin S₃ , and its impurities was studied and used to obtain information about the structures of these impurities.

RESULTS

Based on MS² spectral data and exact mass measurements, the chemical structures of two series of degradation impurities were characterized, among which five unknown impurities were photodegradation impurities and seven unknown impurities were degradation impurities produced in autoclaving of xinfujunsu injection.

CONCLUSIONS

Based on characterization of impurities, this study also revealed the cause of impurity production and provided guidance for enterprises to improve the process and drug packaging material to reduce impurity content. Furthermore, this study also provided scientific basis for further improvement of official monographs in pharmacopoeias.

Challenges, Progress and Promises of Impurities Annotation for LCMSIT- TOF

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Analysis of pharmaceutical products, as well as their active and inactive ingredients, and identification and characterization of potential impurities originating from raw materials and manufacturing processes is of importance in the field, especially for further assessment of potential positive or negative effects on the human body. In addition to expected therapeutic effects, unfortunately, some unwanted or adverse effects were encountered in the past, resulting in dramatic cases sometimes. These challenges have been overcome with the use of sophisticated and high-end analytical techniques today by focusing on developing more efficient, more accurate, more accessible, and faster determination techniques.

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One of the powerful techniques utilized under the given aim, especially for qualitative purposes, is the Time of Flight (TOF) based Mass Spectrometry (MS). Among the TOF-MS instruments, liquid chromatography- mass spectrometry-ion trap-time of flight (LCMS-IT-TOF) has a unique MSn capability, which is a versatile tool in exact mass prediction and structure elucidation. In this review, LCMS-ITTOF has been considered taking all aspects to account for its use in qualitative impurity profiling, and a retrospective view on previous studies was presented in an analytical manner.

Universal response method for the quantitative analysis of multi-components in josamycin and midecamycin using liquid chromatography coupled with charged aerosol detector

Josamycin and midecamycin are consisted of three groups of components with different ultraviolet maximum absorption wavelengths (λ_max), which are 231 nm, 280 nm and 205 nm. The quantitative analysis of all these components is challengeable due to the absence of the respective reference substances. To address this problem, universal and reliable methods were developed using high performance liquid chromatography coupled with charged aerosol detector (HPLC-CAD) for the quantitative analysis of components in josamycin and midecamycin. The chromatographic conditions and CAD parameters setting were optimized. Subsequently, the components were identified using HPLC coupled with ion trap/time-of-flight mass spectrometry (IT/TOF MS). The developed methods were validated by assessing linearity, limit of quantitation (LOQ), accuracy, precision and robustness. Good separations were achieved for all components and the adjustment of the filter valve and power function value efficiently improved sensitivity. The developed methods were more comprehensive than current HPLC-UV method. The experimental results demonstrated good linearity with coefficients of determination (R²) greater than 0.999 in the range of 0.002-0.30 mg mL^-1. The limits of detection (LOD) were ranging from 1.8 to 2.0 μg·mL^-1. The intra-day and inter-day RSD values were less than 2.0 % (n = 6) and 5.6 % (n = 9) respectively. The recoveries were 95.0 %-124.0 % at the spiked concentration levels of 0.05 %, 0.50 %, 0.10 % and 2.5 % with relative standard deviations (RSDs, n = 3) lower than 2.0 %. Finally, the developed methods were successfully applied to the quantitative analysis of minor components and used main components (leucomycin A₃ and midecamycin A₁) as alternative reference substance of minor components. The overall results demonstrated that the HPLC-CAD was a good alternative for the quantitative analysis of multi-components in 16-membered macrolides.

Structural characterization and discrimination of Paris polyphylla var. yunnanensis by a molecular networking strategy coupled with ultra-high-performance liquid chromatography with quadrupole time-of-flight mass spectrometry

RATIONALE

Paris polyphylla var. yunnanensis (Franch) Hand Mazz (PPY) is a traditional Chinese medicine with antitumor, antibacterial, hemostatic, and anthelmintic activities. Identification of the chemical composition in PPY is helpful to discover its active ingredients and can be used to establish its quality control protocols.

METHODS

The composition of PPY was identified using ultra-high-performance liquid chromatography combined with quadrupole time-of-flight mass spectrometry (UHPLC/QTOF-MS/MS) coupled with a molecular networking strategy. First, the UHPLC/QTOF-MS/MS approach was optimized for chemical compound profiling. Then, the MS data were processed using PeakView™ combined with an in-house database to quickly characterize the secondary metabolites. Finally, molecular networking excavated new molecular weights to discover unknown or trace natural products based on the characteristics of each cluster.

RESULTS

A total of 222 compounds, including 77 isospirostanols, 2 spirostanols, 19 furostanols, 10 pseudospirostanols, 6 cholesterols, 10 C₂₁ steroids, 5 insect metamorphosis hormones, 3 plant sterols, 6 five-ring triterpenoids, 4 flavonoids, 8 fatty acids, 2 phenylpropanoids, and 8 other compounds, were characterized in PPY by comparing their main fragmentation characteristics and pathways with the literature data, and 62 of them, 54 steroidals and 8 phenylpropanoids, were discovered or tentatively identified for the first time.

CONCLUSIONS

This study extended the application of a molecular networking strategy to traditional herbal medicines and developed a molecular networking based screening approach with a significant increase in efficiency for the discovery and identification of trace novel natural products.