Online Hydrogen-Deuterium Exchange and a Tandem-Quadrupole Time-of-Flight Mass Spectrometer Coupled with Liquid Chromatography for Metabolite Identification in Drug Metabolism

Nassar, A.-E.F.

doi:10.1093/chromsci/41.8.398

Cited by 48 publications

(24 citation statements)

References 30 publications

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“…These were critical findings on the putative structures of the metabolites. H/D exchange was previously used for metabolite profiling to help in the structural elucidation of small molecule compounds (Nassar, 2003;Liu and Hop, 2005;Prakash et al, 2007;Chen et al, 2009). During H/D exchange, hydrogen atoms attached to heteroatoms (O, N, and S) undergo exchange with deuterium, which results in the increase of molecular ion mass observed in a mass spectrometer.…”

Section: Discussionmentioning

confidence: 99%

“…H/D exchange can be conducted by replacing hydrogen-containing salts and solvents in the mobile phase with fully deuterium-substituted ones (Nassar, 2003;Liu and Hop, 2005). For H/D exchange experiments the chromatographic column was equilibrated with deuterated mobile phases before the injection of study samples.…”

Section: Identification Of Novel Metabolites Of Sch 486757mentioning

confidence: 99%

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Identification of Two Novel Metabolites of SCH 486757, a Nociceptin/Orphanin FQ Peptide Receptor Agonist, in Humans

Penner¹,

Ho²,

Bercovici³

et al. 2010

Drug Metab Dispos

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ABSTRACT:The study of human metabolism of endo-8[bis(2-chlorophenyl)-methyl]-3-(2-pyrimidinyl)-8-azabicyclo[3.2.1]octan-3-ol (SCH 486757) after a 200-mg oral dose of the drug to healthy volunteers in the first-in-human study is presented. The structural elucidation of two unique metabolites, which were detected in the process of metabolite characterization in human plasma and urine by liquid chromatography-mass spectrometry (LC-MS), is described. These metabolites (M27 and M34) were initially detected in human plasma at high levels (>35% of the LC-MS response of the parent drug). Additional LC-MS experiments (hydrogen/deuterium exchange and accurate mass measurement) were used to determine structures of metabolites. It was found that both metabolites were formed through a loss of the C-C bridge from the tropane moiety with the conversion into a substituted pyridinium compound. This metabolic process has not been reported previously. Because of the apparent high abundance of metabolites based on the LC-MS response, actual circulating amounts of these metabolites relative to the parent drug were determined semiquantitatively to evaluate their coverage in preclinical species. With the use of reference standards, it was shown that the LC-MS response of M27 and M34 in human plasma was much higher than that of the parent compound. Actual amounts of M27 and M34 metabolites were less than 5% of the level of the parent drug; therefore, additional assessment was not required.

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Section: Discussionmentioning

confidence: 99%

Section: Identification Of Novel Metabolites Of Sch 486757mentioning

confidence: 99%

Identification of Two Novel Metabolites of SCH 486757, a Nociceptin/Orphanin FQ Peptide Receptor Agonist, in Humans

Penner¹,

Ho²,

Bercovici³

et al. 2010

Drug Metab Dispos

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“…The use of mass spectrometry has become vital to assessment of structure information in complex biologic matrices (Baillie 1992;Mutlib et al, 1995;Pochapsky and Pochapsky 2001;Nassar, 2003;Nassar and Adams, 2003;Watt et al, 2003). Time-of-flight mass spectrometry, a Fourier-transform ion cyclotron resonance-mass spectrometer (FTICR-MS), and Orbitrap mass spectrometers are among the most effective for this work.…”

Section: Abbreviations: Agt Omentioning

confidence: 99%

“…In the online hydrogen-deuterium exchange (H-D) method, developed for use with small molecules, online exchange on column without any further sample preparation is employed for metabolite identification and characterization. H-D has become common practice for online analysis of metabolite identification of complex matrices; when combined with modern mass spectrometry, it has proven ideal for the task of structure confirmation (Nassar, 2003;Nassar and Adams, 2003;Nassar and Talaat, 2004).…”

Section: Abbreviations: Agt Omentioning

confidence: 99%

Biotransformation and Rearrangement of Laromustine

Nassar

Wisnewski

King

2016

Drug Metabolism and Disposition

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This review highlights the recent research into the biotransformations and rearrangement of the sulfonylhydrazine-alkylating agent laromustine. Incubation of [ 14 C]laromustine with rat, dog, monkey, and human liver microsomes produced eight radioactive components (C-1 to C-8). There was little difference in the metabolite profile among the species examined, partly because NADPH was not required for the formation of most components, which instead involved decomposition and/or hydrolysis. The exception was C-7, a hydroxylated metabolite, largely formed by CYP2B6 and CYP3A4/5. Liquid chromatography-multistage mass spectrometry (LC-MS n ) studies determined that collision-induced dissociation, and not biotransformation or enzyme catalysis, produced the unique mass spectral rearrangement. Accurate mass measurements performed with a Fourier-transform ion cyclotron resonance mass spectrometer (FTICR-MS) significantly aided determination of the elemental compositions of the fragments and in the case of laromustine revealed the possibility of rearrangement. Further, collision-induced dissociation produced the loss of nitrogen (N 2 ) and methylsulfonyl and methyl isocyanate moieties. The rearrangement, metabolite/decomposition products, and conjugation reactions were analyzed utilizing hydrogendeuterium exchange, exact mass, 13 C-labeled laromustine, nuclear magnetic resonance spectroscopy (NMR), and LC-MS n experiments to assist with the assignments of these fragments and possible mechanistic rearrangement. Such techniques produced valuable insights into these functions: 1) Cytochrome P450 is involved in C-7 formation but plays little or no role in the conversion of [ 14 C]laromustine to C-1 through C-6 and C-8; 2) the relative abundance of individual degradation/metabolite products was not species-dependent; and 3) laromustine produces several reactive intermediates that may produce the toxicities seen in the clinical trials.

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“…Surprisingly, this method has infrequently been applied for characterization of metabolites° [25][26][27][28][29][30][31][32][33].°The°higher°cost°of°D 2 O could be considered a certain drawback, but the consumption of D 2 O can be significantly reduced by using smaller columns and smaller solvent bottles. Alternatively, fractions can be collected and redissolved in D 2 O containing solvents.…”

Section: H/d Exchangementioning

confidence: 99%

Structural characterization of sulfadiazine metabolites using H/D exchange combined with various MS/MS experiments

Pfeifer¹,

Tuerk

Fuchs³

2005

J. Am. Soc. Mass Spectrom.

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Two major metabolites and one minor metabolite of sulfadiazine were found in pig manure, using a special combination of different MS techniques like parent and product ion scans, H/D exchange, accurate mass measurement, and MS/MS experiments with substructures. N4-acetylsulfadiazine and 4-hydroxysulfadiazine were identified as major metabolites. N4-acetylsulfadiazine could be verified by H/D exchange and comparison with product ion spectra of a synthetic reference compound. In the case of 4-hydroxysulfadiazine, the majority of possible isomers could be discounted after H/D exchange. Substructure-specific MS/MS experiments with fragment ions and comparison with product ion spectra of two references revealed the presence of 4-hydroxysulfadiazine. The minor metabolite was characterized to some degree using H/D exchange and tandem mass spectrometry in combination with a high-resolution time of flight mass spectrometer. The aminopyrimidine moiety contained an additional modification with a likely elemental composition of . Antibiotics and antimicrobial agents are used for both therapeutic and prophylactic purposes in addition to their application as growth promoters. The antimicrobial sulfonamides are one class of pharmaceuticals that is widely used. As a consequence, these compounds have been found in surface and ground water, liquid manure, and soil [3][4][5][6][7][8][9][10][11][12]. After administration to animals, the majority of the pharmaceuticals used are excreted unchanged or as phase I and phase II metabolites. As part of an environmental risk assessment, these metabolites also have to be characterized because phase I metabolites can still be active against bacteria and phase II metabolites can be converted back to the parent drug or phase I metabolites. Moreover, very little is known about the capacity of microbiological decay and the occurrence of new metabolites after incubation for several months in a manure tank.There are only a few references describing the metabolism of sulfadiazine in pigs [13,14]. After intravenous administration of 40 to 60 mg sulfadiazine per kg body weight to male pigs without coadministration of trimethoprim, only low levels of metabolites have been observed. The N-acetyl sulfadiazine was the main metabolite in plasma. Traces of 4-hydroxysulfadiazine were also detected. N-acetyl sulfadiazine and 4-hydroxysulfadiazine were the major metabolites in urine collected up to three hours after application. No further metabolites were identified and investigations in feces were not carried out.The aim of the present work was to use different mass spectrometric strategies to identify possible metabolites of the widely used drug sulfadiazine in manure originating from a pig farm. The metabolites of interest should still have a similar structure as the parent drug and, therefore, retain to a greater or lesser extent their bioactive profile against micro-organisms. Earlier investigations about the biological activity of metabolites showed action of hydroxylated metabolites of sulfadiazine ag...

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Online Hydrogen-Deuterium Exchange and a Tandem-Quadrupole Time-of-Flight Mass Spectrometer Coupled with Liquid Chromatography for Metabolite Identification in Drug Metabolism

Cited by 48 publications

References 30 publications

Identification of Two Novel Metabolites of SCH 486757, a Nociceptin/Orphanin FQ Peptide Receptor Agonist, in Humans

Identification of Two Novel Metabolites of SCH 486757, a Nociceptin/Orphanin FQ Peptide Receptor Agonist, in Humans

Biotransformation and Rearrangement of Laromustine

Structural characterization of sulfadiazine metabolites using H/D exchange combined with various MS/MS experiments

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