The Experts below are selected from a list of 160143 Experts worldwide ranked by ideXlab platform
Bingqi Zhu - One of the best experts on this subject based on the ideXlab platform.
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characterization of two unknown Impurities in roxithromycin by 2d lc qtof ms ms and nmr
Journal of Pharmaceutical and Biomedical Analysis, 2020Co-Authors: Jing Wang, Bingqi Zhu, Jinjin Zhou, Yong JinAbstract:Two unknown Impurities in roxithromycin were discovered and preliminarily characterized by two-dimensional liquid chromatography coupled with QTOF mass analyzer (2D LC-QTOF MS/MS). The column-switching technique of 2D LC made the chromatographic conditions in official standard of roxithromycin compatible with mass spectrometric detector. The complete MS/MS fragmentation patterns of the Impurities were studied to obtain structural information of these Impurities. Furthermore, these two Impurities were separated and purified by preparative HPLC, and their structures were confirmed by 1D and 2D nuclear magnetic resonance (NMR). Structural elucidation of two Impurities by 1H NMR, 13C NMR, the 1H-1H COSY, HSQC and HMBC NMR spectra has been discussed. Based on high resolution MS/MS and NMR data, the structures of these two Impurities were elucidated respectively as 11-O-[(2-Methoxyethoxy) methyl] roxithromycin and de(N-methyl)-N-formyl roxithromycin. In addition, the mechanisms for formation of the Impurities were also proposed.
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study of the impurity profile and polymerized impurity in mezlocillin sodium by multiple heart cutting two dimensional liquid chromatography coupled with ion trap time of flight mass spectrometry
Rapid Communications in Mass Spectrometry, 2019Co-Authors: Jian Wang, Jinjin Zhou, Bingqi ZhuAbstract:RATIONALE Eleven Impurities and one polymerized impurity in mezlocillin were identified and their formation mechanisms were investigated in this study. The sources and reasons for the formation of Impurities were revealed, which may guide industry to improve the manufacturing process and storage conditions and reduce the content of Impurities in products. The results from this study also provided a scientific basis for the improvement of official monographs in pharmacopoeias. METHODS The impurity profiles and polymerized impurity in mezlocillin were studied by multiple heart-cutting two-dimensional liquid chromatography coupled with ion trap time-of-flight mass spectrometry (2D-LC/IT-TOF MS) in both positive and negative modes of electrospray ionization. Target eluents from the first dimensional chromatography with a non-volatile mobile phase were trapped and sent to the second dimensional chromatography with a volatile mobile phase by a switching valve. The structures of the Impurities in the mezlocillin drug substance were deduced based on the high-resolution MSn data. RESULTS In the environment of water, oxygen, high temperature, acid and base, a series of degradation products could be easily produced from mezlocillin. Mezlocillin was hydrolyzed into Impurities I, IV, V and X, and was degraded into impurity III by methanolysis. Mezlocillin was oxidized into sulfoxide by producing impurity XI. Furthermore, Impurities VI, VII, VII and IX were all isomers of mezlocillin. The proposed formation pathways of these products were demonstrated in this study. CONCLUSIONS Eleven degradation Impurities and one polymerized impurity in mezlocillin were separated and characterized. Based on characterization of Impurities, this study discovered the mechanism of impurity production and provided guidance for manufacturers to improve the process and storage conditions and reduce levels of Impurities.
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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
Rapid Communications in Mass Spectrometry, 2019Co-Authors: Guijun Liu, Jing Sang, Bingqi Zhu, Jian WangAbstract:Rationale The toxicities of the Impurities of a drug will affect the clinical effects and cause potential health risk; therefore, it is essential to study profiles of the Impurities. In this study, a new structural type of component and two acid degradation Impurities in josamycin were discovered and characterized for the further improvement of official monographs in pharmacopoeias. Methods The component and acid degradation Impurities in josamycin were separated and preliminary characterized by trap-free two-dimensional liquid chromatography coupled to high-resolution ion trap time-of-flight mass spectrometry (2D LC/IT-TOF MS) in both positive and negative electrospray ionization mode. The eluent of each peak from the first dimensional chromatographic system was trapped by a switching valve and subsequently transferred to the second dimensional chromatographic system, which was connected to the mass spectrometer. Full scan MS was firstly conducted to obtain the exact m/z values of the molecules. Then LC/MS/MS and LC/MS/MS/MS experiments were performed on the compounds of interest. Results A new structural type of component, which was named as josamycin A, and two acid degradation Impuritiess, which were identified as impurity I and impurity II, were discovered in josamycin. Their structures and fragmentation pattern were deduced according to MSn data. Furthermore, josamycin A was synthesized and impurity I was separated by preparative HPLC. The structures of josamycin A and the Impurities were confirmed by 1 H NMR and 13 C NMR data. Conclusions Josamycin A was produced when the hydroxyl group on the macrolide of josamycin was oxidized into a carbonyl group. Impurity I and impurity II were produced by the loss of one molecule of acetyl mycaminose from josamycin and josamycin A, respectively. Compared with josamycin, the experimental results showed that josamycin A had a higher antibacterial activity with similar cytotoxicity, while impurity I had no antibacterial activity but a higher cytotoxicity. As a result, the control of impurity I is significant.
Jian Wang - One of the best experts on this subject based on the ideXlab platform.
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study of the impurity profile and polymerized impurity in mezlocillin sodium by multiple heart cutting two dimensional liquid chromatography coupled with ion trap time of flight mass spectrometry
Rapid Communications in Mass Spectrometry, 2019Co-Authors: Jian Wang, Jinjin Zhou, Bingqi ZhuAbstract:RATIONALE Eleven Impurities and one polymerized impurity in mezlocillin were identified and their formation mechanisms were investigated in this study. The sources and reasons for the formation of Impurities were revealed, which may guide industry to improve the manufacturing process and storage conditions and reduce the content of Impurities in products. The results from this study also provided a scientific basis for the improvement of official monographs in pharmacopoeias. METHODS The impurity profiles and polymerized impurity in mezlocillin were studied by multiple heart-cutting two-dimensional liquid chromatography coupled with ion trap time-of-flight mass spectrometry (2D-LC/IT-TOF MS) in both positive and negative modes of electrospray ionization. Target eluents from the first dimensional chromatography with a non-volatile mobile phase were trapped and sent to the second dimensional chromatography with a volatile mobile phase by a switching valve. The structures of the Impurities in the mezlocillin drug substance were deduced based on the high-resolution MSn data. RESULTS In the environment of water, oxygen, high temperature, acid and base, a series of degradation products could be easily produced from mezlocillin. Mezlocillin was hydrolyzed into Impurities I, IV, V and X, and was degraded into impurity III by methanolysis. Mezlocillin was oxidized into sulfoxide by producing impurity XI. Furthermore, Impurities VI, VII, VII and IX were all isomers of mezlocillin. The proposed formation pathways of these products were demonstrated in this study. CONCLUSIONS Eleven degradation Impurities and one polymerized impurity in mezlocillin were separated and characterized. Based on characterization of Impurities, this study discovered the mechanism of impurity production and provided guidance for manufacturers to improve the process and storage conditions and reduce levels of Impurities.
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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
Rapid Communications in Mass Spectrometry, 2019Co-Authors: Guijun Liu, Jing Sang, Bingqi Zhu, Jian WangAbstract:Rationale The toxicities of the Impurities of a drug will affect the clinical effects and cause potential health risk; therefore, it is essential to study profiles of the Impurities. In this study, a new structural type of component and two acid degradation Impurities in josamycin were discovered and characterized for the further improvement of official monographs in pharmacopoeias. Methods The component and acid degradation Impurities in josamycin were separated and preliminary characterized by trap-free two-dimensional liquid chromatography coupled to high-resolution ion trap time-of-flight mass spectrometry (2D LC/IT-TOF MS) in both positive and negative electrospray ionization mode. The eluent of each peak from the first dimensional chromatographic system was trapped by a switching valve and subsequently transferred to the second dimensional chromatographic system, which was connected to the mass spectrometer. Full scan MS was firstly conducted to obtain the exact m/z values of the molecules. Then LC/MS/MS and LC/MS/MS/MS experiments were performed on the compounds of interest. Results A new structural type of component, which was named as josamycin A, and two acid degradation Impuritiess, which were identified as impurity I and impurity II, were discovered in josamycin. Their structures and fragmentation pattern were deduced according to MSn data. Furthermore, josamycin A was synthesized and impurity I was separated by preparative HPLC. The structures of josamycin A and the Impurities were confirmed by 1 H NMR and 13 C NMR data. Conclusions Josamycin A was produced when the hydroxyl group on the macrolide of josamycin was oxidized into a carbonyl group. Impurity I and impurity II were produced by the loss of one molecule of acetyl mycaminose from josamycin and josamycin A, respectively. Compared with josamycin, the experimental results showed that josamycin A had a higher antibacterial activity with similar cytotoxicity, while impurity I had no antibacterial activity but a higher cytotoxicity. As a result, the control of impurity I is significant.
Jongki Hong - One of the best experts on this subject based on the ideXlab platform.
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impurity profiling and quantification of sudan iii dyes by hplc selective uv detection
Bulletin of The Korean Chemical Society, 2014Co-Authors: Ki Ryeol Yang, Ji Yeon Hong, Soo Hwan Yoon, Jongki HongAbstract:An analytical methodology was developed for qualitative and quantitative impurity profiling of the coloring agent Sudan III by high-performance liquid chromatography (HPLC)-diode array detection (DAD). The Impurities in commercial Sudan III were characterized by comparison of their retention times and UV spectra with those of authentic standards. Four Impurities regulated by International Committees in Sudan III were quantified by HPLC-selective UV detection. The Impurities in Sudan dye were successfully separated on a reversed phase C18-column within 25 min and sensitively detected by UV spectrometry at two selective wavelengths. Method validation was conducted to determine linearity, precision, accuracy, and limit of quantification (LOQ). The linear dynamic range extended from 0.002 to 4.0%, with a correlation coefficient (R2) greater than 0.995. The LOQs of the Impurities ranged from 8.04 to 54.29 µg/mg. Based on the established method, the levels of regulated Impurities in five commercial Sudan III dyes were determined.
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comprehensive impurity profiling and quantification of sudan iii dyes by gas chromatography mass spectrometry
Journal of Chromatography A, 2013Co-Authors: Ji Yeon Hong, Na Hyun Park, Kyung Ho Yoo, Jongki HongAbstract:A novel analysis strategy was created for comprehensive qualitative and quantitative impurity profiling of the coloring agent Sudan III by gas chromatography/mass spectrometry (GC/MS). The identification of Impurities in commercial Sudan III was performed by GC/MS combined with trimethylsilylation (TMS). A total of 24 Impurities were identified or tentatively characterized in commercial Sudan III dyes by GC/MS and were mainly classified as phenylazo and naphtholazo analogs. Four new Impurities with coplanar structures, suspected of being toxic compounds, were observed in commercial Sudan III dyes. For further identification and sensitive detection of polar Impurities, an extract was trimethylsilyl-derivatized to improve the GC chromatographic properties and mass spectrometric detection sensitivity. On the basis of the Impurities identified by GC/MS, pathways for the formation of the major Impurities during the manufacture of Sudan III were suggested. Four Impurities regulated by the EU commission and the US Code of Federal Regulations (CFR) in Sudan III were quantified by GC/MS-scan mode. Method validation was conducted to determine linearity, precision, accuracy, and limit of quantification (LOQ). The linear dynamic range extended from 0.001 to 4.0%, with a correlation coefficient (R(2)) greater than 0.997 for GC/MS. The LOQs of the Impurities ranged from 2.73 to 4.39μg/g for GC/MS. Based on the established method, the levels of regulated Impurities in five commercial Sudan III dyes manufactured by different chemical companies were successfully determined. This study provides very useful information for the quality control of Sudan III and evaluation of its manufacture.
Minoru Isshiki - One of the best experts on this subject based on the ideXlab platform.
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effect of ar ar h2 plasma arc melting on cu purification
Materials Transactions, 2008Co-Authors: J W Lim, Kouji Mimura, Minoru Isshiki, Masahito Uchikoshi, Min Seuk Kim, N R Munirathnam, Hyuk Chon Kwon, Good-sun ChoiAbstract:Removal of Impurities from Cu metal by Ar and Ar-20%H2 plasma arc melting (PAM) has been carried out. Several Impurities such as Li, Na, Mg, P, S, Cl, K, Ca, Zn, Pd, Pb and Bi in Cu were efficiently removed when only Ar plasma gas was used. Moreover, removal degrees for the above mentioned Impurities were significantly increased after Ar-20%H2-PAM, especially for K, Zn and Pd. It was found that Ar-H2 PAM showed an excellent effect to eliminate Impurities with higher vapor pressures than that of Cu metal. [doi:10.2320/matertrans.MRA2008054]
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purification of lanthanum and cerium by plasma arc zone melting
Journal of Materials Science, 2008Co-Authors: Kouji Mimura, Takanori Sato, Minoru IsshikiAbstract:Purification of La and Ce by a horizontal plasma arc-zone melting (PZM) with Ar plasma arc heating under atmospheric pressure was examined. A stable molten zone of La and Ce on the water-cooled copper hearth could be maintained and, after zone passes, the segregation of Impurities along the bars was recognized. Metallic Impurities such as Fe, Cu, Al, and Si moved in the zone direction and decreased efficiently at the head side of the zone-melted bars. Especially, remarkable segregations of those Impurities were observed on La. In addition, volatile Impurities such as Ca, Mg, Zn, and Mn were reduced to further low levels by vaporization. For non-metallic Impurities, O, N, C, and S in Ce, and O and N in La moved in the opposite direction of zoning, while C and S in La moved in the zone direction. Furthermore, nonmetallic Impurities were reduced unexpectedly along the whole bar during PZM. Consequently, the purity around the head side of La and Ce bars could be sufficiently increased with PZM.
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impurity removal from zr nb and ta metals by hydrogen plasma arc melting and thermodynamic estimation of hydride formation
Journal of Alloys and Compounds, 2006Co-Authors: D. Elanski, Jae-won Lim, Kouji Mimura, Minoru IsshikiAbstract:Abstract Commercial Zr, Nb and Ta have been purified by hydrogen plasma arc melting (HPAM) and the removal degree of Impurities was compared with the results of thermodynamic estimations. In the case of Zr and Nb, 40–60% of the total amount of Impurities was removed by Ar plasma melting and 60–80% by HPAM. The Ta melting by HPAM allowed to remove 80% of the total amount of Impurities and to decrease the concentration of almost Impurities down to a few mass ppb levels. For the systems with Ar–H 2 plasma gas, experimental and calculated results are closer to each other than that for the system with Ar plasma gas. According to the thermodynamic calculations, none of Impurities forms hydrides in the gas phase because of the high melting temperatures of these metals. The effect of H 2 addition to the plasma gas on the enhancement of the impurity removal may be attributed to the increase of the surface temperature of molten metals.
Jinjin Zhou - One of the best experts on this subject based on the ideXlab platform.
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characterization of two unknown Impurities in roxithromycin by 2d lc qtof ms ms and nmr
Journal of Pharmaceutical and Biomedical Analysis, 2020Co-Authors: Jing Wang, Bingqi Zhu, Jinjin Zhou, Yong JinAbstract:Two unknown Impurities in roxithromycin were discovered and preliminarily characterized by two-dimensional liquid chromatography coupled with QTOF mass analyzer (2D LC-QTOF MS/MS). The column-switching technique of 2D LC made the chromatographic conditions in official standard of roxithromycin compatible with mass spectrometric detector. The complete MS/MS fragmentation patterns of the Impurities were studied to obtain structural information of these Impurities. Furthermore, these two Impurities were separated and purified by preparative HPLC, and their structures were confirmed by 1D and 2D nuclear magnetic resonance (NMR). Structural elucidation of two Impurities by 1H NMR, 13C NMR, the 1H-1H COSY, HSQC and HMBC NMR spectra has been discussed. Based on high resolution MS/MS and NMR data, the structures of these two Impurities were elucidated respectively as 11-O-[(2-Methoxyethoxy) methyl] roxithromycin and de(N-methyl)-N-formyl roxithromycin. In addition, the mechanisms for formation of the Impurities were also proposed.
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study of the impurity profile and polymerized impurity in mezlocillin sodium by multiple heart cutting two dimensional liquid chromatography coupled with ion trap time of flight mass spectrometry
Rapid Communications in Mass Spectrometry, 2019Co-Authors: Jian Wang, Jinjin Zhou, Bingqi ZhuAbstract:RATIONALE Eleven Impurities and one polymerized impurity in mezlocillin were identified and their formation mechanisms were investigated in this study. The sources and reasons for the formation of Impurities were revealed, which may guide industry to improve the manufacturing process and storage conditions and reduce the content of Impurities in products. The results from this study also provided a scientific basis for the improvement of official monographs in pharmacopoeias. METHODS The impurity profiles and polymerized impurity in mezlocillin were studied by multiple heart-cutting two-dimensional liquid chromatography coupled with ion trap time-of-flight mass spectrometry (2D-LC/IT-TOF MS) in both positive and negative modes of electrospray ionization. Target eluents from the first dimensional chromatography with a non-volatile mobile phase were trapped and sent to the second dimensional chromatography with a volatile mobile phase by a switching valve. The structures of the Impurities in the mezlocillin drug substance were deduced based on the high-resolution MSn data. RESULTS In the environment of water, oxygen, high temperature, acid and base, a series of degradation products could be easily produced from mezlocillin. Mezlocillin was hydrolyzed into Impurities I, IV, V and X, and was degraded into impurity III by methanolysis. Mezlocillin was oxidized into sulfoxide by producing impurity XI. Furthermore, Impurities VI, VII, VII and IX were all isomers of mezlocillin. The proposed formation pathways of these products were demonstrated in this study. CONCLUSIONS Eleven degradation Impurities and one polymerized impurity in mezlocillin were separated and characterized. Based on characterization of Impurities, this study discovered the mechanism of impurity production and provided guidance for manufacturers to improve the process and storage conditions and reduce levels of Impurities.
