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Ofloxacin ear drops contain a large proportion of organic solvents, which have a great effect on the photodegradation of ofloxacin. The photodegradation impurities of ofloxacin in aqueous solution has been studied, however, the photodegradation of ofloxacin in non-aqueous solution with a high proportion of organic solvents has not been reported. In this article, the impurity profile in non-aqueous ofloxacin ear drops was studied for further improvement of official monograph in pharmacopoeia and quality control of drug. The liquid chromatography combined with ion trap/time-of-flight mass spectrometry was applied to separate and characterize the structures of the impurities in non-aqueous ofloxacin ear drops. Mass fragmentation pattern of ofloxacin and its impurities were studied. The structures of seventeen impurities in ofloxacin ear drops were elucidated based on the high-resolution MSn data in positive ion modes, and ten of them were unknown impurities. The results showed that the impurity profile of non-aqueous ofloxacin solution was significantly different from that of aqueous ofloxacin solution. The effects of packaging materials and excipients on the photodegradation of ofloxacin ear drops were also investigated. The results of correlation analysis showed that the packaging materials with low light transmittance could reduce the light degradation, and ethanol of excipients could significantly decrease the light stability of ofloxacin ear drops. This study revealed the impurity profile and key factors affecting the photodegradation of non-aqueous ofloxacin ear drops, and guided enterprises to improve drug prescription and packaging materials to ensure the safety of drug use by the public.

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Artemisia rupestris is widely used as a folk medicine of Uygur and Kazak with blood and detoxification, deaccumulation stagnation, clearing heat digestion and other effects. Currently, the chemical profile of A. rupestris has not been disclosed, resulting in a great obstacle for the systematic clarification of the efficacy materials and the quality evaluations. In this paper, HPLC-IT-TOF-MS was deployed to characterize the chemical constituents in A. rupestris. As a result, a total of 124 compounds were detected in 75% ethanol extract of A. rupestris. By comparing with the reference compounds, seven chlorogenic acids, and four flavonoids as well as one sesquiterpenoid were definitely identified. Moreover, twenty sesquiterpenes, sixty-five flavonoids and twenty-three chlorogenic acids were preliminarily identified by matching MS/MS spectral information with literature data and applying those empirical mass spectrometric cracking rules. In current study, the chemical composition of A. rupestris was profiled in depth, and the findings are envisioned to provide a theoretical basis for the further studies of this well-known herbal medicine, such as efficacy material characterization and quality assessment.

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Saikosaponins are the representative bioactive ingredient in the Radix Bupleuri. Previous studies have reported that saikosaponins are prone to losing their glycones and being converted to corresponding prosaikogenins and saikogenins by intestinal bacteria. However, the microsomal cytochrome P450-mediated metabolism of these deglycosylated metabolites is still unknown. This research performed in vitro studies of five saikogenins in rat and human liver microsomes. High-performance liquid chromatography coupled with a hybrid ion trap and time-of-flight mass spectrometry (HPLC-IT/TOF-MS) was employed to identify the metabolites. To confirm the metabolites detected in vitro, plasma and feces obtained from rats administrating several saikogenins were also analyzed by high-performance liquid chromatography with triple-quadrupole mass spectrometry (HPLC-QqQ-MS). The in vitro metabolic stability of saikogenins was ranked as follows: SGF＞SGG＞SGE＞SGA＞SGD. A total of 71 metabolites generated by hydroxylation, carboxylation, and dehydrogenation, as well as combinations of these steps, were identified by accurate mass measurement and MSn fragmentation behavior. Among eight metabolic pathways, monohydroxylation or carboxylation was the major metabolic pathway both in vitro and in vivo. Analysis of in vivo biological samples suggested that analytical targets for saikogenins should be the compounds themselves and their oxidized metabolites. This research provides a basis for further studies of the in vivo metabolism of saikosaponins in humans.

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The qualitative analysis of flavonoids in Coreopsis tinctoria was carried out by a combination of 2 D-TLC and HPLC-IT-TOF-MS. The separation was conducted on 2 D-TLC and a Phenomenex Kinetex Evo C_(18) column(2.1 mm×100 mm, 2.6 µm) with methanol-0.05% aqueous formic acid by gradient elution. Electrospray ionization-(ESI) source was applied and operated in both positive and negative ionization modes. Eighteen flavonoids including three flavonoids, one flavonol, nine flavonones, one flavanonol and four chalcones, were putatively identified from the flavone-enriched fraction of C. tinctoria. 2 D-TLC could separate the flavonoids from C. tinctoria. HPLC-IT-TOF-MS was able to quickly and accurately analyze the flavonoids in C. tinctoria. The results would provide experimental information for the efficacy material basis clarification of C. tinctoria.

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Marsdenia tenacissima, or Tongguanteng in Chinese, is a traditional Chinese herb and has a broad application in clinical practice for its pharmacological effects of treating asthma, pneumonia, tonsillitis, pharyngitis tumors, etc. However, few studies have reported the screening of the active components of this medicine for tumor therapy. In this work, a two-dimensional analytical system was developed to screen antagonists of epidermal growth factor receptor (EGFR) from M. tenacissima. A fraction was retained on the EGFR cell membrane chromatography (CMC) column, separated and identified as tenacissoside G (TG), tenacissoside H (TH) and tenacissoside I (TI) by two-dimensional HPLC-IT-TOF-MS. Molecular docking and 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay were carried out to assess the activity of TS (including TG, TH and TI). Molecular docking results showed that the binding mode of TS on EGFR is similar to that of gefitinib. The MTT assay demonstrated that gefitinib and TS (especially TI) could inhibit the growth of EGFR highly expressed cell lines in a dose-dependent manner in the range of 5-50 µmol/L. In conclusion, the two-dimensional EGFR/CMC-HPLC-IT-TOF-MS system could be a useful approach in drug discovery from traditional Chinese medicines for searching for potential antitumor candidates.

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A novel and effective method was established for the qualitative analysis of impurities in auramine O samples of illegal food additives using high performance liquid chromatography-ion trap-time of flight mass spectrometry (HPLC-IT-TOF-MS). An impurity was identified in the auramine O sample using the optimized HPLC-IT-TOF-MS method. According to the exact mass of each fragment ion measured by multistage MS, the structure of the impurity was determined to be that of 4-(imino (4-(methylamino) phenyl) methyl)-N,N-dimethylaniline hydrochloride. The synthetic route of the auramine O and the source of the identified impurity were proposed. Simultaneously, a preparative high performance liquid chromatography (prep-HPLC) technique was successfully applied for the purification of the auramine O from complex samples. Prep-HPLC columns with particle sizes of 10 µm and 5 µm were used for the separation and purification with injection volumes of 1 mL and 500 µL, respectively. Finally an auramine O reference standard with 99.52% purity was obtained by secondarily purification and determined by the analytical HPLC area normalization method. Deducting the 0.34% moisture content and 0.13% ash content, the final purity of the sample was 99.05%, as determined by mass balance method. The chemical structure was examined using UV, IR, LC-MS, and NMR. The developed method is simple and efficient, and can be applied for the preparation of reference standard materials for other illegal food additives.

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The qualitative analysis of flavonoids in Coreopsis tinctoria was carried out by a combination of 2 D-TLC and HPLC-IT-TOF-MS. The separation was conducted on 2 D-TLC and a Phenomenex Kinetex Evo C_(18) column(2.1 mm×100 mm, 2.6 μm) with methanol-0.05% aqueous formic acid by gradient elution. Electrospray ionization-(ESI) source was applied and operated in both positive and negative ionization modes. Eighteen flavonoids including three flavonoids, one flavonol, nine flavonones, one flavanonol and four chalcones, were putatively identified from the flavone-enriched fraction of C. tinctoria. 2 D-TLC could separate the flavonoids from C. tinctoria. HPLC-IT-TOF-MS was able to quickly and accurately analyze the flavonoids in C. tinctoria. The results would provide experimental information for the efficacy material basis clarification of C. tinctoria.

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A method for the identification of relevant impurities in illegal o-chlorophenyl cyclopentyl ketone drug was developed. Identification of impurities could help regulation of this illegal drug and allow the sources of samples of the drug to be identified. An efficient and effective method for qualitatively analyzing samples using high performance liquid chromatography-hybrid ion trap/time-of-flight mass spectrometry (HPLC-IT/TOF MS) was developed. The o-chlorophenyl cyclopentyl ketone fragmentation pathway during HPLC-MSn was determined by analyzing a standard by HPLC-IT/TOF MS. The optimized HPLC-IT/TOF MS method allowed two impurities in o-chlorophenyl cyclopentyl ketone samples to be identified. According to the exact mass data of MSn and the element composition analysis, two impurities were identified as o-chlorobenzoic acid anhydride and 1,2-di-o-chlorobenzoylcyclopentene. The synthetic route of the o-chlorophenyl cyclopentyl ketone samples was proposed by analysis of these impurities. The established method made it easy to identify impurities and find the source of this illegal drug. A method for the preparation an o-chlorophenyl cyclopentyl ketone reference standard from actual samples using preparative HPLC was also developed. The mobile phase was methanol-water (85:15, v/v) and flow rate was 8 mL/min. The purity of the obtained standards, determined by analytical HPLC, was 99.53%. This method is simple, efficient, and can be used for the preparation of other illegal drugs.

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Objective To in depth analyze the chemical profile of Marsdenia tenacissima using HPLC-IT-TOF-MS. Methods The pulverized materials were exacted with methanol in an ultrasonication manner and then separated on a Waters Acquity UPLC HSS T3 column (100 mm × 2.1 mm, 1.8 μm, Milford, MA, USA) that was eluted in gradient with 0.1% formic acid-acetonitrile. The data was collected using automatically triggered tandem mass spectrometric mode in positive/negative ionization polarities. The mass fragmentation patterns of polyoxypregnane derivatives were proposed using some authentic compounds. Results Six chlorogenic acid derivatives and 15 polyoxypregnane derivatives were definitely assigned by referring to reference components, whereas the other signals, including 100 polyoxypregnane derivatives, four flavonoids, and two chlorogenic acid derivatives were tentatively annotated via matching the acquired information with those achieved information and the proposed mass fragmentation rules. Conclusion The research efficiently and accurately analyzed the chemical profile of M. tenacissima using HPLC-IT-TOF-MS, which will provide meaningful information for the quality evaluation and the therapeutic mechanism investigation of M. tenacissima as well as its preparation Xiao-Ai-Ping.

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Objective: To analyze the chemical constituent cluster of decoction of Sanguisorba Radix systemically by HPLC-IT-TOF/MS. Methods: The samples were scanned by broad spectrum of DAD detector and ionized in negative and positive environment of electron spray ionization. Results: A total of 82 chemical constituents (include isomers) were identified based on exact molecular mass, fragment, ultraviolet spectrum as well as the combination of the database. The chemical constituent cluster was composed of 69 phenolics, 8 triterpenes, 3 flavonoids, an organic acid, and a monoterpene glycoside, of which citric acid, brevifolin carboxylic acid, methoxybenzoic acid methyl ester-5-O-sulfate, isorhamnetin-sulfate, and methylellagic acid-sulfate, et al were firstly found in Sanguisorba Radix. Conclusion: The systemical analysis of the chemical constituent cluster of decoction of Sanguisorba Radix was able to supply a clear material basis for the further study of efficacy and pharmaceutical metabolism of Sanguisorba Radix.

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Yejuhua (YJH) injection is a traditional Chinese medicine (TCM) injection and has a widely application in clinical practice. However, adverse drug reactions (ADRs) caused by YJH injection, majorly manifested as allergic reactions, have been reported. Hence, Effective and practical method for allergen screening and identification is needed. In this work, a LAD2/CMC model coupled online with HPLC-IT-TOF-MS system was developed to screen, analyze, and identify the allergenic components of YJH injection. A fraction was retained on the LAD2/CMC column, and identified as linarin (LN). Histamine release assay was performed by the multiple reaction monitoring (MRM) method of UPLC-ESI-MS/MS. Results showed that YJH injection and LN were in accord with their allergic effects by increasing histamine release. In conclusion, the LAD2/CMC-HPLC-IT-TOF-MS system developed in this study could be used to screen allergenic components in complex systems.

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OBJECTIVE: To investigate the impurity profile of raloxifene thus to lay a foundation for the establishment of drug quality standard. METHODS: HPLC-IT-TOF-MS was adopted to analyze destroyed raloxifene and reference substances of impurities. According to the mass spectrometry fragmentation patterns of known impurities, the structures of unknown impurities were speculated. RESULTS: Destroyed raloxifene totally produced three impurities, one of which was unknown. Based on the regular mass spectrometry fragmentation patterns of raloxifene and known impurities, the unknown impurity was speculated to be a sulfone that was generated through further oxidation of raloxifene. CONCLUSION: The methods and results of this study could lay a foundation for the impurity control during production and in vivo analysis of raloxifene.