Strategies for characterization of drug metabolites using liquid chromatography–tandem mass spectrometry in conjunction with chemical derivatization and on-line H/D exchange approaches

Liu, David Q.; Hop, Cornelis E. C. A.

doi:10.1016/j.jpba.2004.09.003

Cited by 164 publications

(99 citation statements)

References 74 publications

(82 reference statements)

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“…Multiple reaction monitoring (MRM) was performed for each transition with a dwell time of 500 ms. The identity of the putative metabolites found in FS mode was corroborated by MRM transitions, which give the best selectivity and sensitivity in HPLC-MS/MS (Liu and Hop, 2005) and confirmed by product ion scan MS/MS experiments on the molecular ion and/or fragment ions.…”

Section: Hplc-ms and Hplc-ms/msmentioning

confidence: 74%

Absorption and Metabolization of Cytoprotective Epicatechin Thio Conjugates in Rats

Selga

Vinardell²,

Martín‐Venegas³

et al. 2010

Drug Metab Dispos

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ABSTRACT:The epicatechin (EC) thio derivatives 4␤-(S-cysteinyl)-epicatechin (Cys-EC) and 4␤-(S-cysteaminyl)-epicatechin (Cya-EC) are compounds that may provide protection from oxidation via mechanisms involving either the flavonoid moiety or the nonphenolic cysteine or cysteamine part of the molecule. Because the metabolically modified molecules may be the actual active species, we estimated the absorption/metabolization of the thio derivatives through the small intestine in vitro and studied the body distribution of the compounds and their metabolites in rats. The analysis of the samples generated was done using a highperformance liquid chromatograph coupled to a UV detector and a tandem mass spectrometer. We show that Cya-EC follows the same phase II metabolization pattern as EC, whereas Cys-EC is transported with the intact catechol moiety through the small intestine and effectively metabolized systemically. We also found that Cya-EC generates Cys-EC in vivo, which provides evidence for a Cya-EC-mediated cytoprotective effect through cysteamine/cystine exchange with subsequent cysteine transport, ubiquitously throughout the organism.

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Section: Hplc-ms and Hplc-ms/msmentioning

confidence: 74%

Absorption and Metabolization of Cytoprotective Epicatechin Thio Conjugates in Rats

Selga

Vinardell²,

Martín‐Venegas³

et al. 2010

Drug Metab Dispos

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“…The new generation of linear ion traps offers the possibility to combine CNL, PreIS, or MRM with a product ion scan on a linear ion trap to acquire a mass spectrum of every signal detected within one single separation, since the third quadrupole is constructed as an ion trap [16]. In addition to the specificity of the survey scans, the product ion spectrum provides additional data to elucidate the structure of unknowns or to confirm known analytes [17].…”

mentioning

confidence: 99%

Rapid detection and identification of N-acetyl-L-cysteine thioethers using constant neutral loss and theoretical multiple reaction monitoring combined with enhanced product-ion scans on a linear ion trap mass spectrometer

Scholz

Dekant

Völkel

et al. 2005

J. Am. Soc. Mass Spectrom.

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A sensitive and specific liquid chromatography-mass spectrometry (LC-MS) method based on the combination of constant neutral loss scans (CNL) with product ion scans was developed on a linear ion trap. The method is applicable for the detection and identification of analytes with identical chemical substructures (such as conjugates of xenobiotics formed in biological systems) which give common CNLs. A specific CNL was observed for thioethers of N-acetyl-L-cysteine (mercapturic acids, MA) by LC-MS/MS. MS and HPLC parameters were optimized with 16 MAs available as reference compounds. All of these provided a CNL of 129 Da in the negative-ion mode. To assess sensitivity, a multiple reaction monitoring (MRM) mode with 251 theoretical transitions using the CNL of 129 Da combined with a product ion scan (IDA thMRM) was compared with CNL combined with a product ion scan (IDA CNL). An information-dependent acquisition (IDA) uses a survey scan such as MRM (multiple reaction monitoring) to generate "informations" and starting a second acquisition experiment such as a product ion scan using these "informations." Th-MRM means calculated transitions and not transitions generated from an available standard in the tuning mode. The product ion spectra provide additional information on the chemical structure of the unknown analytes. All MA standards were spiked in low concentrations to rat urines and were detected with both methods with LODs ranging from 60 pmol/mL to 1.63 nmol/mL with IDA thMRM. The expected product ion spectra were observed in urine. Application of this screening method to biological samples indicated the presence of a number of MAs in urine of unexposed rats, and resulted in the identification of 1,4-dihydroxynonene mercapturic acid as one of these MAs by negative and positive product ion spectra. These results show that the developed methods have a high potential to serve as both a prescreen to detect unknown MAs and to identify these analytes in complex matrix. (J Am Soc Mass Spectrom 2005, 16, 1976 -1984

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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%

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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Strategies for characterization of drug metabolites using liquid chromatography–tandem mass spectrometry in conjunction with chemical derivatization and on-line H/D exchange approaches

Cited by 164 publications

References 74 publications

Absorption and Metabolization of Cytoprotective Epicatechin Thio Conjugates in Rats

Absorption and Metabolization of Cytoprotective Epicatechin Thio Conjugates in Rats

Rapid detection and identification of N-acetyl-L-cysteine thioethers using constant neutral loss and theoretical multiple reaction monitoring combined with enhanced product-ion scans on a linear ion trap mass spectrometer

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

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