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Liquid Chromatography/Mass Spectrometry Methods for Distinguishing N-Oxides from Hydroxylated Compounds

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Department of Drug Metabolism and Pharmacokinetics, Schering-Plough Research Institute, Kenilworth, New Jersey 07033
Cite this: Anal. Chem. 2000, 72, 6, 1352–1359
Publication Date (Web):February 19, 2000
Copyright © 2000 American Chemical Society

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    This study describes the application of liquid chromatography/mass spectrometry (LC/MS) methods for distinguishing between aliphatic and aromatic hydroxylations and between hydroxylations and N-oxidations. Hydroxylations and N-oxidations are common biotransformation reactions of drugs. Electrospray (ESI) and atmospheric pressure chemical ionization (APCI) were used to generate ions from liquid chromatographic effluents. ESI-MS, ESI-MS/MS, APCI-MS, and APCI-MS/MS experiments were performed on several metabolites and derivatives of loratadine (a long-acting and nonsedating tricyclic antihistamine) using an ion trap mass spectrometer (LCQ) and a triple-quadrupole mass spectrometer (TSQ). The observations are as follows:  (1) LC/ESI-MS produced predominantly [M + H]+ ions with minor fragmentation. (2) LC/ESI-MS/MS data, however, showed a predominant loss of water from metabolites with aliphatic hydroxylation while the loss of water was not favored when hydroxylation was phenolic. N-Oxides (aromatic and aliphatic) showed only a small amount of water loss in the MS/MS spectra. (3) Under LC/APCI-MS conditions, aliphatic hydroxylation could be readily distinguished from aromatic hydroxylation based on the extent of water loss. In addition, N-oxides produced distinct [M + H − O]+ ions. These [M + H − O]+ ions were not produced in the APCI-MS spectra of hydroxylated metabolites. (4) Similar to the ESI-MS/MS spectra, the APCI-MS/MS spectra from the (M + H)+ ions of N-oxides yielded a small amount of water loss but no [M + H − O]+ ions. These results indicate that LC/APCI-MS can be used to distinguish between hydroxylated metabolites and N-oxides.

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     Corresponding author:  (fax) (908) 740-3966; (e-mail) swapan.chowdhury@

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    51. Li‐Kang Zhang, Birendra N. Pramanik. Mass Spectral Interpretation. 2014, 1-37.
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    59. Mohammed Jemal, Yuan‐qing Xia. Quantitative Mass Spectrometry Considerations in a Regulated Environment. 2013, 55-95.
    60. Natalia Penner, Joanna Zgoda‐Pols, Chandra Prakash. Metabolite Identification Using Mass Spectrometry in Drug Development. 2013, 115-147.
    61. L. Sridhar, R. Karthikraj, M.R.V.S. Murty, N. Prasada Raju, M. Vairamani, S. Prabhakar. Mass spectral analysis of N-oxides of nitrogen mustards, and N,N-dialkylaminoethyl-2-chlorides under electrospray ionization conditions. International Journal of Mass Spectrometry 2013, 333 , 15-20.
    62. Silvi A. Chacko, Ragu Ramanathan, W. Griffith Humphreys, Jonathan L. Josephs. Hybrid Mass Analyzers in Drug Metabolism Applications. 2012, 1-38.
    63. . Oxidative Degradation. 2012, 48-109.
    64. Roger N. Hayes. Leveraging Advances in HPLC and Sample Preparation to Maximize DMPK Data Quality. 2012, 1-29.
    65. Anton Kaufmann. High Mass Resolution Versus MS/MS. 2012, 169-215.
    66. Pat Wright. Metabolite identification by mass spectrometry: forty years of evolution. Xenobiotica 2011, 41 (8) , 670-686.
    67. Marie-Pierre Taillon, Cynthia Côté, Milton Furtado, Fabio Garofolo. Potentially New Isobaric Metabolite of Fluvastatin Observed by LC–MS/MS During Incurred Sample Analysis. Bioanalysis 2011, 3 (16) , 1827-1835.
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    69. Li‐Kang Zhang, Birendra N. Pramanik. Mass Spectral Interpretation. 2011, 321-351.
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    71. L. Sridhar, R. Karthikraj, M. R. V. S. Murty, N. Prasada Raju, M. Vairamani, S. Prabhakar. Mass spectral analysis of N ‐oxides of Chemical Weapons Convention related aminoethanols under electrospray ionization conditions. Rapid Communications in Mass Spectrometry 2011, 25 (4) , 533-542.
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    73. S. Beuck, W. Schänzer, M. Thevis. Investigation of the in vitro metabolism of the emerging drug candidate S107 for doping‐preventive purposes. Journal of Mass Spectrometry 2011, 46 (2) , 112-130.
    74. Wenkui Li, Jie Zhang, Francis L. S. Tse. Strategies in quantitative LC‐MS/MS analysis of unstable small molecules in biological matrices. Biomedical Chromatography 2011, 25 (1-2) , 258-277.
    75. Michael T. Furlong, Chad E. Wujcik, Chengjie Ji, Yi Su. Identifying and overcoming bioanalytical challenges associated with chlorine-containing dehydrogenation metabolites. Rapid Communications in Mass Spectrometry 2010, 24 (21) , 3092-3102.
    76. Xin Wang, Min Li, Abu M. Rustum. Thermally induced intramolecular oxygen migration of N ‐oxides in atmospheric pressure chemical ionization mass spectrometry. Rapid Communications in Mass Spectrometry 2010, 24 (19) , 2805-2811.
    77. Andrew J. Bessire, Alfin D. N. Vaz, Gregory S. Walker, Wei Wei Wang, Raman Sharma. The use of 18 O‐exchange and base‐catalyzed N ‐dealkylation with liquid chromatography/tandem mass spectrometry to identify carbinolamide metabolites. Rapid Communications in Mass Spectrometry 2010, 24 (14) , 2151-2161.
    78. Michael Furlong, Andrew Bessire, Wei Song, Christopher Huntington, Elizabeth Groeber. Use of high‐resolution mass spectrometry to investigate a metabolite interference during liquid chromatography/tandem mass spectrometric quantification of a small molecule in toxicokinetic study samples. Rapid Communications in Mass Spectrometry 2010, 24 (13) , 1902-1910.
    79. Ragu Ramanathan, Jonathan L Josephs, Mohammed Jemal, Mark Arnold, W Griffith Humphreys. Novel MS Solutions Inspired by MIST. Bioanalysis 2010, 2 (7) , 1291-1313.
    80. Michal Holčapek, Robert Jirásko, Miroslav Lísa. Basic rules for the interpretation of atmospheric pressure ionization mass spectra of small molecules. Journal of Chromatography A 2010, 1217 (25) , 3908-3921.
    81. Annica Tevell Åberg, Helena Löfgren, Ulf Bondesson, Mikael Hedeland. Structural elucidation of N ‐oxidized clemastine metabolites by liquid chromatography/tandem mass spectrometry and the use of Cunninghamella elegans to facilitate drug metabolite identification. Rapid Communications in Mass Spectrometry 2010, 24 (10) , 1447-1456.
    82. Steven C. Habicht, Penggao Duan, Nelson R. Vinueza, Mingkun Fu, Hilkka I. Kenttämaa. Liquid chromatography/tandem mass spectrometry utilizing ion-molecule reactions and collision-activated dissociation for the identification of N-oxide drug metabolites. Journal of Pharmaceutical and Biomedical Analysis 2010, 51 (4) , 805-811.
    83. Silvan Eichenberger, Michaël Méret, Stefan Bienz, Laurent Bigler. Decomposition of N ‐hydroxylated compounds during atmospheric pressure chemical ionization. Journal of Mass Spectrometry 2010, 45 (2) , 190-197.
    84. Tove Johansson, Lars Weidolf, Friedrich Popp, Reinhold Tacke, Ulrik Jurva. In Vitro Metabolism of Haloperidol and Sila-Haloperidol: New Metabolic Pathways Resulting from Carbon/Silicon Exchange. Drug Metabolism and Disposition 2010, 38 (1) , 73-83.
    85. Mohammed Jemal, Zheng Ouyang, Yuan-Qing Xia. Systematic LC-MS/MS bioanalytical method development that incorporates plasma phospholipids risk avoidance, usage of incurred sample and well thought-out chromatography. Biomedical Chromatography 2010, 24 (1) , 2-19.
    86. Ragu Ramanathan, S Çömezoglu, W Humphreys. Metabolite Identification Strategies and Procedures. 2009, 127-203.
    87. Wei Song, Deepthi Pabbisetty, Elizabeth A. Groeber, Rick C. Steenwyk, Douglas M. Fast. Comparison of fused-core and conventional particle size columns by LC–MS/MS and UV: Application to pharmacokinetic study. Journal of Pharmaceutical and Biomedical Analysis 2009, 50 (3) , 491-500.
    88. Xiao-Hong Sun, Feng Man, Li-Yan Pang, Gui-Hua Gao, Xiao-Qin Li, Xiu-Lan Qi, Fa-Mei Li. Fungal biotransformation of mosapride by Cunninghamella elegans. Journal of Molecular Catalysis B: Enzymatic 2009, 59 (1-3) , 82-89.
    89. Nicolas Picard, Dorra Dridi, François‐Ludovic Sauvage, Naceur A. Boughattas, Pierre Marquet. General unknown screening procedure for the characterization of human drug metabolites: Application to loratadine phase I metabolism. Journal of Separation Science 2009, 32 (13) , 2209-2217.
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    91. Ari Tolonen, Miia Turpeinen, Olavi Pelkonen. Liquid chromatography–mass spectrometry in in vitro drug metabolite screening. Drug Discovery Today 2009, 14 (3-4) , 120-133.
    92. Guodong Chen, Ibrahim Daaro, Birendra N. Pramanik, John J. Piwinski. Structural characterization of in vitro rat liver microsomal metabolites of antihistamine desloratadine using LTQ‐Orbitrap hybrid mass spectrometer in combination with online hydrogen/deuterium exchange HR‐LC/MS. Journal of Mass Spectrometry 2009, 44 (2) , 203-213.
    93. Natalia A. Penner, Joanna Zgoda‐Pols, Ragu Ramanathan, Swapan K. Chowdhury, Kevin B. Alton. LC–MS Methods with Hydrogen/Deuterium Exchange for Identification of Hydroxylamine , N‐ Oxide, and Hydroxylated Analogs of Desloratadine. 2008, 295-310.
    94. Zhengyin Yan, Noureddine Maher, Rhoda Torres, Carlos Cotto, Becki Hastings, Malini Dasgupta, Rolanda Hyman, Norman Huebert, Gary W. Caldwell. Isobaric metabolite interferences and the requirement for close examination of raw data in addition to stringent chromatographic separations in liquid chromatography/tandem mass spectrometric analysis of drugs in biological matrix. Rapid Communications in Mass Spectrometry 2008, 22 (13) , 2021-2028.
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    97. R. Ramanathan, L. Reyderman, K. Kulmatycki, A.-D. Su, N. Alvarez, S. K. Chowdhury, K. B. Alton, M. A. Wirth, R. P. Clement, P. Statkevich, J. E. Patrick. Disposition of loratadine in healthy volunteers. Xenobiotica 2007, 37 (7) , 753-769.
    98. R. Ramanathan, L. Reyderman, A.-D. Su, N. Alvarez, S. K. Chowdhury, K. B. Alton, M. A. Wirth, R. P. Clement, P. Statkevich, J. E. Patrick. Disposition of desloratadine in healthy volunteers. Xenobiotica 2007, 37 (7) , 770-787.
    99. Guodong Chen, Birendra N. Pramanik, Yan‐Hui Liu, Urooj A. Mirza. Applications of LC/MS in structure identifications of small molecules and proteins in drug discovery. Journal of Mass Spectrometry 2007, 42 (3) , 279-287.
    100. Xiaoying Xu. 11 HPLC method development for drug discovery LC-MS assays in rapid PK applications. 2007, 317-351.
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