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Straub M, Auderset A, de Leval L, Piazzon N, Maison D, Vozenin MC, Ollivier J, Petit B, Sigman DM, Martínez-García A. Nitrogen isotopic composition as a gauge of tumor cell anabolism-to-catabolism ratio. Sci Rep 2023; 13:19796. [PMID: 37957187 PMCID: PMC10643536 DOI: 10.1038/s41598-023-45597-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 10/21/2023] [Indexed: 11/15/2023] Open
Abstract
Studies have suggested that cancerous tissue has a lower 15N/14N ratio than benign tissue. However, human data have been inconclusive, possibly due to constraints on experimental design. Here, we used high-sensitivity nitrogen isotope methods to assess the 15N/14N ratio of human breast, lung, and kidney cancer tissue at unprecedented spatial resolution. In lung, breast, and urothelial carcinoma, 15N/14N was negatively correlated with tumor cell density. The magnitude of 15N depletion for a given tumor cell density was consistent across different types of lung cancer, ductal in situ and invasive breast carcinoma, and urothelial carcinoma, suggesting similar elevations in the anabolism-to-catabolism ratio. However, tumor 15N depletion was higher in a more aggressive metaplastic breast carcinoma. These findings may indicate the ability of certain cancers to more effectively channel N towards growth. Our results support 15N/14N analysis as a potential tool for screening biopsies and assessing N metabolism in tumor cells.
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Affiliation(s)
- Marietta Straub
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.
- Max Planck Institute for Chemistry, 55128, Mainz, Germany.
| | - Alexandra Auderset
- Max Planck Institute for Chemistry, 55128, Mainz, Germany
- School of Ocean and Earth Science, University of Southampton, Southampton, SO14 3ZH, UK
| | - Laurence de Leval
- Institute of Pathology, Department of Laboratory Medicine and Pathology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Nathalie Piazzon
- Institute of Pathology, Department of Laboratory Medicine and Pathology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Damien Maison
- Institute of Pathology, Department of Laboratory Medicine and Pathology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Marie-Catherine Vozenin
- Radiation Oncology Laboratory/DO/Radio-Oncology/CHUV, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Jonathan Ollivier
- Radiation Oncology Laboratory/DO/Radio-Oncology/CHUV, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Benoît Petit
- Radiation Oncology Laboratory/DO/Radio-Oncology/CHUV, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Daniel M Sigman
- Department of Geosciences, Princeton University, Princeton, NJ, 08544, USA
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Straub M, Sigman DM, Auderset A, Ollivier J, Petit B, Hinnenberg B, Rubach F, Oleynik S, Vozenin MC, Martínez-García A. Distinct nitrogen isotopic compositions of healthy and cancerous tissue in mice brain and head&neck micro-biopsies. BMC Cancer 2021; 21:805. [PMID: 34256713 PMCID: PMC8276491 DOI: 10.1186/s12885-021-08489-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 06/10/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cancerous cells can recycle metabolic ammonium for their growth. As this ammonium has a low nitrogen isotope ratio (15N/14N), its recycling may cause cancer tissue to have lower 15N/14N than surrounding healthy tissue. We investigated whether, within a given tissue type in individual mice, tumoral and healthy tissues could be distinguished based on their 15N/14N. METHODS Micro-biopsies of murine tumors and adjacent tissues were analyzed for 15N/14N using novel high-sensitivity methods. Isotopic analysis was pursued in Nude and C57BL/6 mice models with mature orthotopic brain and head&neck tumors generated by implantation of H454 and MEERL95 murine cells, respectively. RESULTS In the 7 mice analyzed, the brain tumors had distinctly lower 15N/14N than healthy neural tissue. In the 5 mice with head&neck tumors, the difference was smaller and more variable. This was at least partly due to infiltration of healthy head&neck tissue by tumor cells. However, it may also indicate that the 15N/14N difference between tumoral and healthy tissue depends on the nitrogen metabolism of the healthy organ in question. CONCLUSIONS The findings, coupled with the high sensitivity of the 15N/14N measurement method used here, suggest a new approach for micro-biopsy-based diagnosis of malignancy as well as an avenue for investigation of cancer metabolism.
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Affiliation(s)
- M Straub
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, 1007 Lausanne, Switzerland.
- Max Planck Institute for Chemistry, 55128, Mainz, Germany.
| | - D M Sigman
- Department of Geosciences, Princeton University, Princeton, NJ, 08544, USA
| | - A Auderset
- Max Planck Institute for Chemistry, 55128, Mainz, Germany
| | - J Ollivier
- Radiation Oncology Laboratory/DO/Radio-Oncology/CHUV, Lausanne University Hospital and University of Lausanne, 1011 Lausanne, Switzerland
| | - B Petit
- Radiation Oncology Laboratory/DO/Radio-Oncology/CHUV, Lausanne University Hospital and University of Lausanne, 1011 Lausanne, Switzerland
| | - B Hinnenberg
- Max Planck Institute for Chemistry, 55128, Mainz, Germany
| | - F Rubach
- Max Planck Institute for Chemistry, 55128, Mainz, Germany
| | - S Oleynik
- Department of Geosciences, Princeton University, Princeton, NJ, 08544, USA
| | - M-C Vozenin
- Radiation Oncology Laboratory/DO/Radio-Oncology/CHUV, Lausanne University Hospital and University of Lausanne, 1011 Lausanne, Switzerland
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Philips A, Raja D, Arumugam A, Lin W, Chandru Senadi G. Copper‐Catalyzed Oxidative C−C Cleavage of Carbohydrates: An Efficient Access to Quinazolinone Scaffolds. ASIAN J ORG CHEM 2021. [DOI: 10.1002/ajoc.202100317] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Abigail Philips
- Department of Chemistry, Faculty of Engineering and Technology SRM Institute of Science and Technology Kattankulathur Tamilnadu 603203 India
- Department of Medicinal and Applied Chemistry Kaohsiung Medical University Kaohsiung 80708 Taiwan
| | - Dineshkumar Raja
- Department of Chemistry, Faculty of Engineering and Technology SRM Institute of Science and Technology Kattankulathur Tamilnadu 603203 India
| | - Ajithkumar Arumugam
- Department of Chemistry, Faculty of Engineering and Technology SRM Institute of Science and Technology Kattankulathur Tamilnadu 603203 India
| | - Wei‐Yu Lin
- Department of Medicinal and Applied Chemistry Kaohsiung Medical University Kaohsiung 80708 Taiwan
- Department of Medical Research Kaohsiung Medical University Hospital Kaohsiung 80708 Taiwan
| | - Gopal Chandru Senadi
- Department of Chemistry, Faculty of Engineering and Technology SRM Institute of Science and Technology Kattankulathur Tamilnadu 603203 India
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Sanford AB, Jarvo ER. Harnessing C-O Bonds in Stereoselective Cross-Coupling and Cross-Electrophile Coupling Reactions. Synlett 2020; 32:1151-1156. [PMID: 34354327 PMCID: PMC8329764 DOI: 10.1055/s-0040-1705987] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Herein, we discuss our laboratory's research in the activation of alcohol derivatives in cross-coupling and cross-electrophile coupling reactions. Our developed methods enable the use of secondary alcohols to afford tertiary stereogenic centers, which we applied to the synthesis of pharmaceutically relevant compounds and substructures. We first discuss the synthesis of bioactive compounds via stereospecific Kumada cross-coupling reactions, followed by a discussion on the development of our stereoselective cross-electrophile coupling reaction to synthesize cyclopropanes.
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Affiliation(s)
- Amberly B Sanford
- Department of Chemistry, University of California, Irvine Natural Sciences II, Irvine, CA, 92697-2025
| | - Elizabeth R Jarvo
- Department of Chemistry, University of California, Irvine Natural Sciences II, Irvine, CA, 92697-2025
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Delcourt V, Barnabé A, Loup B, Garcia P, André F, Chabot B, Trévisiol S, Moulard Y, Popot MA, Bailly-Chouriberry L. MetIDfyR: An Open-Source R Package to Decipher Small-Molecule Drug Metabolism through High-Resolution Mass Spectrometry. Anal Chem 2020; 92:13155-13162. [DOI: 10.1021/acs.analchem.0c02281] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Vivian Delcourt
- GIE-LCH, Laboratoire des Courses Hippiques, 15 rue de Paradis, 91370 Verrières-le-Buisson, France
| | - Agnès Barnabé
- GIE-LCH, Laboratoire des Courses Hippiques, 15 rue de Paradis, 91370 Verrières-le-Buisson, France
| | - Benoit Loup
- GIE-LCH, Laboratoire des Courses Hippiques, 15 rue de Paradis, 91370 Verrières-le-Buisson, France
| | - Patrice Garcia
- GIE-LCH, Laboratoire des Courses Hippiques, 15 rue de Paradis, 91370 Verrières-le-Buisson, France
| | - François André
- GIE-LCH, Laboratoire des Courses Hippiques, 15 rue de Paradis, 91370 Verrières-le-Buisson, France
| | - Benjamin Chabot
- GIE-LCH, Laboratoire des Courses Hippiques, 15 rue de Paradis, 91370 Verrières-le-Buisson, France
| | - Stéphane Trévisiol
- GIE-LCH, Laboratoire des Courses Hippiques, 15 rue de Paradis, 91370 Verrières-le-Buisson, France
| | - Yves Moulard
- GIE-LCH, Laboratoire des Courses Hippiques, 15 rue de Paradis, 91370 Verrières-le-Buisson, France
| | - Marie-Agnès Popot
- GIE-LCH, Laboratoire des Courses Hippiques, 15 rue de Paradis, 91370 Verrières-le-Buisson, France
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Dawson DD, Jarvo ER. Stereospecific Nickel-Catalyzed Cross-Coupling Reactions of Benzylic Ethers with Isotopically-Labeled Grignard Reagents. Org Process Res Dev 2015; 19:1356-1359. [PMID: 27458328 PMCID: PMC4955521 DOI: 10.1021/acs.oprd.5b00148] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Indexed: 01/08/2023]
Abstract
![]()
In
this manuscript we highlight the potential of stereospecific
nickel-catalyzed cross-coupling reactions for applications in the
pharmaceutical industry. Using an inexpensive and sustainable nickel
catalyst, we report a gram-scale Kumada cross-coupling reaction. Reactions
are highly stereospecific and proceed with inversion at the benzylic
position. We also expand the scope of our reaction to incorporate
isotopically labeled substituents.
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Affiliation(s)
- David D Dawson
- Department of Chemistry, University of California , Irvine, California 92697-2025, United States
| | - Elizabeth R Jarvo
- Department of Chemistry, University of California , Irvine, California 92697-2025, United States
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Luo H, DuBois B, Sgambelluri RM, Angelos ER, Li X, Holmes D, Walton JD. Production of (15)N-labeled α-amanitin in Galerina marginata. Toxicon 2015; 103:60-4. [PMID: 26100667 DOI: 10.1016/j.toxicon.2015.06.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Revised: 06/15/2015] [Accepted: 06/17/2015] [Indexed: 11/30/2022]
Abstract
α-Amanitin is the major causal constituent of deadly Amanita mushrooms that account for the majority of fatal mushroom poisonings worldwide. It is also an important biochemical tool for the study of its target, RNA polymerase II. The commercial supply of this bicyclic peptide comes from Amanita phalloides, the death cap mushroom, which is collected from the wild. Isotopically labeled amanitin could be useful for clinical and forensic applications, but α-amanitin has not been chemically synthesized and A. phalloides cannot be cultured on artificial medium. Using Galerina marginata, an unrelated saprotrophic mushroom that grows and produces α-amanitin in culture, we describe a method for producing (15)N-labeled α-amanitin using growth media containing (15)N as sole nitrogen source. A key to success was preparing (15)N-enriched yeast extract via a novel method designated "glass bead-assisted maturation." In the presence of the labeled yeast extract and (15)N-NH4Cl, α-amanitin was produced with >97% isotope enrichment. The labeled product was confirmed by HPLC, high-resolution mass spectrometry, and NMR.
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Affiliation(s)
- Hong Luo
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA; Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China.
| | - Brandon DuBois
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA
| | - R Michael Sgambelluri
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA; Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Evan R Angelos
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA
| | - Xuan Li
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA; Department of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650091, Yunnan, China
| | - Daniel Holmes
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Jonathan D Walton
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA.
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Abstract
INTRODUCTION Deuterated versions of existing drugs can exhibit improved pharmacokinetic or toxicological properties due the stronger deuterium- carbon bond modifying their metabolism. There is great interest in the current state of development of this approach. AREAS COVERED This review covers recent US patent applications and prosecutions in this area that are based on beneficial modifications in metabolism of deuterated versions of existing drugs. The current state of 35 U.S.C. §103 'obviousness' rejections are emphasized, as is the development of strategies to overcome such rejections. Current trials and market considerations are also discussed. EXPERT OPINION Deuterated drugs collectively are worth at least US$1 billion. It would seem that the likelihood of obviousness rejections is increasing in this area. However, careful elucidation of metabolic outcomes from deuteration that would not be anticipated from the prior art, and are instead unexpected and unobvious, has enabled allowance. Showing that drug deuteration alters pharmacokinetics by mechanisms not currently part of the prior art surrounding deuterated drugs has also been successful. Development of these and other strategies, combined with developing the extensive base of issued patents will enable the field to remain commercially attractive for some time.
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Affiliation(s)
- Graham S Timmins
- University of New Mexico Health Sciences Center, College of Pharmacy, Department of Pharmaceutical Sciences , Albuquerque, NM 87131 , USA +1 505 272 4103 ; +1 505 272 6749 ;
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Hunsinger GB, Stern LA. Improved accuracy in high-temperature conversion elemental analyzer δ18O measurements of nitrogen-rich organics. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2012; 26:554-562. [PMID: 22302495 DOI: 10.1002/rcm.6132] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
RATIONALE The use of high-temperature conversion (HTC) reduction systems interfaced with isotope ratio mass spectrometers for δ(18)O measurements of nitrogen-containing organic materials is complicated by isobaric interference from (14)N(16)O(+). This ion is produced in the ion source when N(2) reacts with trace oxygen shifting the m/z 30 baseline prior to elution of CO. METHODS We compared adaptations to a typical HTC system (TC/EA) to determine the best method to measure the δ(18)O values of nitrogen-rich organic substrates including: (1) 0.6 and 1.5 m 5 Å molecular sieve GC columns; (2) reduction of N(2) peak via He dilution; and (3) diversion of N(2) to waste via an automated four-port valve. These methods were applied to caffeine (IAEA-600), glycine, 4-nitroacetanilide, pentaerythritol tetranitrate (PETN) and cyclotrimethylene trinitramine (RDX), as well as pure and sodium azide-doped benzoic acid (IAEA-601) and sucrose (IAEA-CH6). RESULTS The efficiency of N(2) production in the HTC interface was highly variable among these compounds. Both the longer column and the dilutor improved, but did not eliminate, the adverse effects of nitrogen. CONCLUSIONS The diversion of N(2) adequately addressed the nitrogen-induced problems as indicated by: (1) consistent m/z 30 background offset between reference and sample CO for both N-free and N-rich materials; (2) production of the highest δ(18)O values; and (3) high correlation between the increase in the δ(18)O values relative to the GC-only measurements and the N(2) peak area. Additional validation would require N-rich oxygen isotope standards for inter-laboratory comparisons. Further, more stringent methodology may improve the poor inter-laboratory δ(18)O reproducibility of IAEA-600.
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Affiliation(s)
- Glendon B Hunsinger
- Counterterrorism and Forensic Science Research Unit, FBI Laboratory, Quantico, VA 22135, USA
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10
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Singh R, Arlt VM, Henderson CJ, Phillips DH, Farmer PB, Gamboa da Costa G. Detection and quantitation of N-(deoxyguanosin-8-yl)-2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine adducts in DNA using online column-switching liquid chromatography tandem mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci 2010; 878:2155-62. [PMID: 20598652 PMCID: PMC2923026 DOI: 10.1016/j.jchromb.2010.06.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2010] [Revised: 06/03/2010] [Accepted: 06/03/2010] [Indexed: 10/19/2022]
Abstract
The heterocyclic aromatic amine, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is formed by the grilled cooking of certain foods such as meats, poultry and fish. PhIP has been shown to induce tumours in the colon, prostate and mammary glands of rats and is regarded as a potential human dietary carcinogen. PhIP is metabolically activated via cytochrome P450 mediated oxidation to an N-hydroxylamino-PhIP intermediate that is subsequently converted to an ester by N-acetyltransferases or sulfotransferases and undergoes heterolytic cleavage to produce a PhIP-nitrenium ion, which reacts with DNA to form the N-(deoxyguanosin-8-yl)-2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP-C8-dG) adduct. Thus far, the detection and quantification of PhIP-DNA adducts has relied to a large extent on (32)P-postlabelling methodologies. In order to expand the array of available techniques for the detection and improved quantification of PhIP-C8-dG adducts in DNA we have developed an online column-switching liquid chromatography (LC)-electrospray ionization (ESI)-tandem mass spectrometry (MS/MS) selected reaction monitoring (SRM) method incorporating an isotopically [(13)C(10)]-labelled PhIP-C8-dG internal standard for the analysis of DNA enzymatically hydrolysed to 2'-deoxynucleosides. A dose-dependent increase was observed for PhIP-C8-dG adducts when salmon testis DNA was reacted with N-acetoxy-PhIP. Analysis of DNA samples isolated from colon tissue of mice treated by oral gavage daily for 5 days with 50 mg/kg body weight of PhIP resulted in the detection of an average level of 14.8+/-3.7 PhIP-C8-dG adducts per 10(6) 2'-deoxynucleosides. The method required 50 microg of hydrolysed animal DNA on column and the limit of detection for PhIP-C8-dG was 2.5 fmol (1.5 PhIP-C8-dG adducts per 10(8) 2'-deoxynucleosides). In summary, the LC-ESI-MS/MS SRM method provides for the rapid automation of the sample clean up and a reduction in matrix components that would otherwise interfere with the mass spectrometric analysis, with sufficient sensitivity and precision to analyse DNA adducts in animals exposed to PhIP.
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Affiliation(s)
- Rajinder Singh
- Cancer Biomarkers and Prevention Group, Biocentre, Department of Cancer Studies and Molecular Medicine, University of Leicester, University Road, Leicester LE1 7RH, UK.
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Yamazaki S, Toth LN, Kimoto E, Bower J, Skaptason J, Romero D, Heath TG. Application of stable isotope methodology in the evaluation of the pharmacokinetics of (S,S)-3-[3-(methylsulfonyl)phenyl]-1-propylpiperidine hydrochloride in rats. Drug Metab Dispos 2009; 37:937-45. [PMID: 19237512 DOI: 10.1124/dmd.108.025478] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The primary objective of this study was to demonstrate the use of stable isotope (SI)-labeled compound as an approach for pharmacokinetic analysis such as fraction absorbed, hepatic extraction ratio, and fraction metabolized from the parent drug to a metabolite. (S,S)-3-[3-(Methylsulfonyl)phenyl]-1-propylpiperidine hydrochloride (PNU96391) was selected as the model compound because of its simple biotransformation pathway, i.e., the predominant metabolic pathway to the N-despropyl metabolite (M1), which makes it a suitable candidate. The second objective was to fully characterize the pharmacokinetics of PNU96391 in rats using the SI coadministration approach with quantitative analysis by liquid chromatography-tandem mass spectrometry. Overall the present study showed that 1) absorption of PNU96391 from the gastrointestinal tract was near complete (>90% of the dose), 2) PNU96391 was predominantly metabolized to M1 (approximately 70% of the dose), and 3) M1 was exclusively eliminated into urine with negligible biotransformation (ratio of renal clearance to plasma clearance approximately 0.9). Therefore, the present study demonstrated the utility of the SI methodology for characterizing the pharmacokinetics of a compound within the drug discovery and development process. Furthermore, the compartmental pharmacokinetic modeling provided insights into the disposition and biotransformation rates of PNU96391 and M1, suggesting that the modeling could add further advantages to the SI coadministration approach. Despite the greater availability of SI-labeled compounds, absorption, distribution, metabolism, and excretion (ADME) scientists have yet to take full advantage of the potential use of these analogs for mechanistic ADME studies. These SI-labeled compounds can be used more widely to gain a better understanding of ADME properties in drug discovery and development.
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Affiliation(s)
- Shinji Yamazaki
- Pharmacokinetics, Dynamics and Metabolism, La Jolla Laboratories, Pfizer Global Research and Development, 10777 Science Center Dr., San Diego, CA 92121, USA.
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Teichert F, Verschoyle RD, Greaves P, Thorpe JF, Mellon JK, Steward WP, Farmer PB, Gescher AJ, Singh R. Determination of 8-oxo-2'-deoxyguanosine and creatinine in murine and human urine by liquid chromatography/tandem mass spectrometry: application to chemoprevention studies. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2009; 23:258-266. [PMID: 19072863 DOI: 10.1002/rcm.3873] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) represents a non-invasive biomarker for oxidative stress and may be useful for monitoring chemotherapeutic and chemopreventive interventions associated with cancer-related alterations in oxidative stress. We describe the development and validation of two separate liquid chromatography/tandem mass spectrometry (LC/MS/MS) selected reaction monitoring (SRM) methods for the determination of 8-oxodG and creatinine in both murine and human urine using stable isotope labelled internal standards. Levels of 8-oxodG were normalised to creatinine. The LC/MS/MS methods were applied to two chemoprevention studies utilising tea polyphenols in humans and TRAMP (TRansgenic Adenocarcinoma of the Mouse Prostate) mice. Patients with benign prostatic hyperplasia received 1 g/day of green tea polyphenols (GTP), 1 g/day of black tea theaflavins (BTT) or no treatment for 4 weeks. TRAMP mice received GTP (0.05% in drinking water) for 4 or 25 weeks. Prostate pathology in TRAMP mice was not affected by GTP. Levels of 8-oxodG were not altered by tea polyphenols in either mice or humans. In TRAMP mice, urinary 8-oxodG levels were elevated with increasing age (p < 0.0001) but not changed by the presence of prostate tumours. In conclusion, the LC/MS/MS SRM methods described here are ideally suited for the accurate determination of 8-oxodG and creatinine in urine samples from both clinical and pre-clinical studies.
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Affiliation(s)
- Friederike Teichert
- Cancer Biomarkers and Prevention Group, Department of Cancer Studies and Molecular Medicine, University of Leicester, UK.
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Mutlib AE. Application of stable isotope-labeled compounds in metabolism and in metabolism-mediated toxicity studies. Chem Res Toxicol 2008; 21:1672-89. [PMID: 18702535 DOI: 10.1021/tx800139z] [Citation(s) in RCA: 136] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Stable isotope-labeled compounds have been synthesized and utilized by scientists from various areas of biomedical research during the last several decades. Compounds labeled with stable isotopes, such as deuterium and carbon-13, have been used effectively by drug metabolism scientists and toxicologists to gain better understanding of drugs' disposition and their potential role in target organ toxicities. The combination of stable isotope-labeling techniques with mass spectrometry and nuclear magnetic resonance (NMR) spectroscopy, which allows rapid acquisition and interpretation of data, has promoted greater use of these stable isotope-labeled compounds in absorption, distribution, metabolism, and excretion (ADME) studies. Examples of the use of stable isotope-labeled compounds in elucidating structures of metabolites and delineating complex metabolic pathways are presented in this review. The application of labeled compounds in mechanistic toxicity studies will be discussed by providing an example of how strategic placement of a deuterium atom in a drug molecule mitigated specific-specific renal toxicity. Other examples from the literature demonstrating the application of stable isotope-labeled compounds in understanding metabolism-mediated toxicities are presented. Furthermore, an example of how a stable isotope-labeled compound was utilized to better understand some of the gene changes in toxicogenomic studies is discussed. The interpretation of large sets of data produced from toxicogenomics studies can be a challenge. One approach that could be used to simplify interpretation of the data, especially from studies designed to link gene changes with the formation of reactive metabolites thought to be responsible for toxicities, is through the use of stable isotope-labeled compounds. This is a relatively unexplored territory and needs to be further investigated. The employment of analytical techniques, especially mass spectrometry and NMR, used in conjunction with stable isotope-labeled compounds to establish and understand mechanistic link between reactive metabolite formation, genomic, and proteomic changes and onset of toxicity is proposed. The use of stable isotope-labeled compounds in early human ADME studies as a way of identifying and possibly quantifying all drug-related components present in systemic circulation is suggested.
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Affiliation(s)
- Abdul E Mutlib
- Biotransformation Department, Drug Safety and Metabolism, Wyeth Research, Collegeville, Pennsylvania 19426, USA.
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15
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Baba S, Furuta T, Sasaki Y, Kasuya Y. Synthesis of deuterium-labeled imipramine using acid-catalyzed exchange reaction. J Labelled Comp Radiopharm 2006. [DOI: 10.1002/jlcr.2580220208] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Nassar AEF, Bjorge SM, Lee DY. On-line liquid chromatography-accurate radioisotope counting coupled with a radioactivity detector and mass spectrometer for metabolite identification in drug discovery and development. Anal Chem 2003; 75:785-90. [PMID: 12622367 DOI: 10.1021/ac025934f] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A novel detection method combining on-line liquid chromatography-accurate radioisotope counting (LC-ARC, advanced stop flow controller) coupled with a radioactivity detector and mass spectrometer has been developed. One of the major benefits of this method is that this system enhances the sensitivity of radioisotope measurement for metabolite identification in drug metabolism studies. Another advantage to this system is the easy interface with the mass spectrometer, which allows acquisition of mass spectrometric data on-line. For purposes of evaluating this system, in vitro microsomal incubations with [3Hlpropranolol were conducted. On-line separation and identification of [3H]propranolol metabolites was achieved without intensive sample preparation, concentration, or fraction collection. Mass spectrometric analysis showed the presence of propranolol major metabolites formed by hydroxylation, correlating with previously published results. Further evaluations of this system also were conducted using two 14C compounds, which are herein labeled X and Y. As our results show, 14C peaks were detected down to 6 cpm, which is approximately 20 times more sensitive than commercially available flow through radioactivity detectors. The overall results suggest that the combination of LC-ARC with radioactivity detection and mass spectrometry has great potential as a powerful tool for improving the sensitivity of radioisotope measurement in metabolite identification studies during drug discovery and development.
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Affiliation(s)
- A E F Nassar
- Department of Pharmacokinetics and Drug Metabolism, Bayer Corporation, 400 Morgan Lane, West Haven, Connecticut 06516-4175, USA.
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Faragher RJ, Motto JM, Kaminski MA, Schwan AL. A convenient synthesis of13C4-Leflunomide and its primary metabolite13C4-A77 1726. J Labelled Comp Radiopharm 2003. [DOI: 10.1002/jlcr.701] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Dobson RL, Kelm GR, Neal DM. Automated gas chromatography/tandem mass spectrometry assay for tebufelone and a 13C,(18)O-labeled analog in plasma: applicabilityto absolute bioavailability determination. BIOLOGICAL MASS SPECTROMETRY 1994; 23:75-81. [PMID: 8123692 DOI: 10.1002/bms.1200230206] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
An automated capillary gas chromatography/tandem mass spectrometry (GC/MS/MS) assay for the simultaneous quantitation of tebufelone (TE) and 13C, (18)O-labeled TE (TE-CO) in plasma was developed. This method permits the use of stable isotope coadministration (TE and TE-CO dosed concurrently via peroral and intravenous routes, respectively) for the determination of TE absolute bioavailability. The selectivity of MS/MS conducted on a triple-quadrupole instrument allowed minimal sample preparation and rapid analysis. Electron ionization produced molecular ions (M+) for TE, TE-CO, and the 3-methyl-TE internal standard which were selected in Q1 to undergo collisionally activated dissociation in Q2. Quantitation was achieved through monitoring product ions at m/z 248, 251 and 248, respectively, in Q3. A 2-1000 ng per sample (40 pg to 20 ng injected) quantitation range provided access to an effective 1-5000 p.p.b. plasma concentration range (0.2-2 g samples) for both TE and TE-CO. The assay showed no bias and less than 8% relative standard deviation over the entire range. The method was used to determine plasma levels of TE and TE-CO in four dogs receiving 2.5:2.5 mg/kg TE:TE-CO, intravenously. The pharmacokinetics of both isotopomers proved to be identical, indicating no isotope effect and verifying the chemical stability of the (18)O-carbonyl label under these dosing conditions. In addition, the applicability of this analytical approach to the determination of TE peroral bioavailability was initially tested in dogs.
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Affiliation(s)
- R L Dobson
- Procter & Gamble Pharmaceuticals, Miami Valley Laboratories, Cincinnati, OH 45239-8707
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Chace DH, Abramson FP. Isotope dilution studies: determination of carbon-13, nitrogen-15 and deuterium-enriched compounds using capillary gas chromatography-chemical reaction interface/mass spectrometry. BIOMEDICAL & ENVIRONMENTAL MASS SPECTROMETRY 1990; 19:117-22. [PMID: 2184905 DOI: 10.1002/bms.1200190305] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In addition to the ability of a capillary gas chromatographic-chemical reaction interface/mass spectrometric technique (CRIMS) to detect the presence of 13C, 15N and 2H (D) it can also quantify the level of the enriched substance. The microwave-powered chemical reaction interface converts materials from their original forms into small molecules whose mass spectra serve to identify and quantify the nuclides which make up each analyte. The presence of enrichment of each element is followed by monitoring the isotopic variants of CO2, NO or H2 which are produced in the chemical reaction interface. Chromatograms showing only enriched 13C and 15N are produced by subtracting the abundance of naturally occurring isotopes from the observed M + 1 signal. A selective chromatogram of 2H (D) is obtained by measuring HD at m/z 3.0219 with a resolution of 2000. Enrichment of 13C and 15N is quantified by measuring the ratio of excess 13CO2 to total 12CO2 or excess 15NO to total 14NO. To evaluate linearity and detection limits, we have used phenytoin as an example of an unlabeled substance and added various labeled phenytoin analogs. Atom enrichments of 0.3% were detectable for (2,4,5-13C3) phenytoin and 0.06% for (1,3-15N2)labeled phenytoin, each in the presence of 500 ng of unlabeled phenytoin, respectively. For deuterium, enrichment could not be directly determined. However, 1 ng of (ring D10) phenytoin was determined in the presence of 500 ng of unlabeled diethylated phenytoin. We have found CRIMS capable of quantifying 13C-, 15N- and D-enriched substances.
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Affiliation(s)
- D H Chace
- Department of Pharmacology, George Washington University Medical Center, Washington, DC 20037
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Chapman TE, Kraan GP, Drayer NM, Nagel GT, Wolthers BG, Colenbrander B, Fentener-van Vlissingen M. Are (13C)cortisol and (3H)cortisol metabolized identically to natural cortisol in adrenalectomized piglets? BIOMEDICAL & ENVIRONMENTAL MASS SPECTROMETRY 1988; 17:343-53. [PMID: 3061511 DOI: 10.1002/bms.1200170502] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Adrenalectomized piglets were intravenously administered a mixture of (13C4)cortisol and (3H)cortisol and natural cortisol to determine if the two tracers are metabolized identically to natural cortisol. Urine was collected after 0.5, 1.0, 1.5 and 2.0 days and the isotope dilution was measured in the four major urinary cortisol metabolites, namely tetrahydrocortisone (THE), tetrahydrocortisol (THF), alpha- and beta-cortolone in the cumulative urines. In contrast to other studies, because of the sensitivity of the method used to measure the 13C4 enrichment, non-cumulative urine collections were also analysed. Quantification of the 13C4 isotope enrichment was carried out by gas chromatography/mass spectrometry with selected ion monitoring. The specific activities of the metabolites from the cumulative urine collections were determined by high-performance liquid chromatography and scintillation counting. Small secondary isotope effects seemed to occur during the metabolism of (13C4)cortisol, as a decrease in isotope enrichment in all four metabolites was measured. These effects were easily observed with alpha- and beta-cortolone isolated from the cumulative urine collections; the enrichment decreased by 19% and 14%, respectively. The lowering in isotope dilution in THE observed in the 2.0 day cumulative urine collection in piglets 1 and 2 were 4% and 3%, respectively. A lowering in isotope dilution in THF in the 2.0 day cumulative urine collection could be observed in piglet 2, namely 7%, but no change in isotope dilution could be seen in piglet 1. These secondary isotope effects could only be observed in the 2 days cumulative urine, and not in the cumulative urines collected over shorter times. The non-cumulative urines collected at half-day periods showed a significant decrease in isotope dilution in THE and THF isolated from the urine collected after 1 day. No statistically significant isotope effects were observed with the metabolism of (3H)cortisol, except at 0.5 day when the specific activity in the cortolones was lower and that in THF was higher. However, at 0.5 day with THE and 1.0 day with THF and the cortolones the specific activities remained approximately 6% higher than that administered in the cortisol. Secondary isotope effects with tritiated cortisol may have occurred but because of the relatively large imprecision of the measurement (SD = 3-4% with THE and THF and the cortolones (SD approximately 8%) compared to the measurements of the 13C4 enrichment (SD approximately 2%) these effects could not statistically be proven.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- T E Chapman
- Department of Paediatrics, University Hospital, Groningen, The Netherlands
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Benchekroun Y, Ribon B, Desage M, Brazier JL. Simultaneous quantitation of phenobarbitone and p-hydroxyphenobarbitone and their perdeuteroethyl analogues in biological fluids by combined gas chromatography-mass spectrometry. JOURNAL OF CHROMATOGRAPHY 1987; 420:287-96. [PMID: 3693502 DOI: 10.1016/0378-4347(87)80185-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
In order to develop 5-pentadeuteroethyl-5-phenyl barbituric acid as an alternative tracer in pharmacokinetic and metabolic studies of phenobarbitone, and to search for possible isotope effects associated with such labelling, we propose a gas chromatographic-mass spectrometric assay for simultaneous measurement of phenobarbitone, p-hydroxyphenobarbitone and their perdeuteroethyl analogues, using [1,3-15N2,2-13C] phenobarbitone as internal standard. These compounds were extracted from plasma (50 microliter) or urine (500 microliter) and pentylated according to Greeley's method. Linear calibration curves were obtained in the concentration range from 0.5 to 3 micrograms/ml. The interday precision, mean accuracy and detection limit were 0.77-5.28%, 99.99-100.80% and 0.03-0.05 microgram/ml, respectively. Results for plasma and urine concentrations, and pharmacokinetic parameters in humans, are presented to illustrate this method.
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Affiliation(s)
- Y Benchekroun
- Laboratoire d'Etudes Analytiques et Cinétiques du Medicament Faculté de Pharmacie, Lyon, France
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Abstract
This article surveys the role of stable isotope labelling and mass spectrometric detection in the recognition and characterization of drug metabolites. Applications of the so-called isotope cluster technique, useful for both recognition of drug-related compounds and elucidation of their structures, are presented. The use of deuterium-labelled g.l.c./mass spectrometric derivatization reagents to facilitate the determination of drug metabolite structures via 'peak shifts' is illustrated.
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Fischer C, Heuer B, Heuck K, Eichelbaum M. Quantification of nitrendipine by stable isotope dilution and electron-capture negative ion chemical ionization. BIOMEDICAL & ENVIRONMENTAL MASS SPECTROMETRY 1986; 13:645-50. [PMID: 2952187 DOI: 10.1002/bms.1200131202] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The electron-capture properties of nitrendipine, a 1,4-dihydro-pyridine derivative with antihypertensive activity, have been applied to develop a sensitive and specific assay in biological fluids using capillary column gas chromatography and measurement in negative ion chemical ionization mode. The synthesis of a 13C4-labelled analogue suitable as a biological internal standard for bioavailability studies and of a 2H8-labelled analogue, which serves as internal standard, is described. The electron-capture positive ion chemical ionization and electron-capture negative ion chemical ionization mass spectra of nitrendipine and its isotope-labelled analogues are compared. The assay has a detection limit of 100 pg ml-1 plasma with a coefficient of variation of 10.2% using the selected ion monitoring mode and electron-capture negative ion chemical ionization. The method is specific, sensitive and accurate to determine terminal half-life times after intravenous and oral administration of nitrendipine and its 13C-analogue. From the nearly identical plasma concentration-time profile of nitrendipine and its 13C-labelled analogue, an isotopic effect can be excluded. Thus, the synthesized 13C4-analogue should be well suited as a biological standard for bioavailability studies.
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Hatch F, McKellop K, Hansen G, MacGregor T. Relative bioavailability of metaproterenol in humans utilizing a single dose, stable isotope approach. J Pharm Sci 1986; 75:886-90. [PMID: 3783458 DOI: 10.1002/jps.2600750913] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The relative bioavailability of metaproterenol (3,5-dihydroxy-alpha-[(isopropylamino)methyl]benzyl alcohol) following a single dose (10-mg metaproterenol sulfate tablet) was studied in six normal male volunteers using coadministration of a solution of a deuterated analogue (metaproterenol-d7 sulfate). The bioavailability of the tablet formulation relative to that of the oral solution was 92 +/- 9%, with excellent power at the 5% significance level. Comparison of the coadministration of the labeled and unlabeled metaproterenol sulfate solutions in two subjects after a one-week washout demonstrated the absence of an isotope effect on either absorption or elimination. A GC-MS assay for metaproterenol was developed to measure plasma concentrations resulting from oral administration. The assay was linear over the range of 0.5-8 ng/mL, corresponding to typical plasma metaproterenol concentrations obtained after a single 10-mg oral dose. Accuracy and precision data were obtained at metaproterenol concentrations of 1.0 and 2.0 ng/mL plasma to demonstrate the applicability of the assay for bioavailability studies. Following oral administration, metaproterenol showed peak plasma concentrations of 2.2 to 13 ng/mL at 0.75 to 3.0 h, with a terminal harmonic mean half-life of 2.1 h over the plasma concentration range studied. The renal clearance of 133-158 mL/min for metaproterenol slightly exceeds the glomerular filtration rate in humans.
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Theis DL, Halstead GW, Halm KA. Development of capillary gas chromatographic-mass spectrometric methodology for the simultaneous determination of ibuprofen and [ar-2H4]ibuprofen in serum: demonstration of kinetic equivalence in the beagle. JOURNAL OF CHROMATOGRAPHY 1986; 380:77-87. [PMID: 3745396 DOI: 10.1016/s0378-4347(00)83626-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A capillary gas chromatographic-mass spectrometric method for the determination of ibuprofen and tetra-deuterated ibuprofen in serum is described. Ibuprofen, [ar-2H4]ibuprofen and the internal standard, [ar-2H4,3,3,3-2H3]ibuprofen, are extracted (after acidification) from serum onto a cross-linked styrene divinyl benzene resin by an automated sample processor. After elution and evaporation of the organic phase, samples are reconstituted with solvent and analyzed without derivatization by capillary gas chromatography-mass spectrometry. This methodology was used to evaluate possible kinetic isotope effects after the coadministration of an equimolar mixture of ibuprofen and the deuterium-labeled covariant in the beagle. No significant differences in absorption or elimination were observed.
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Abstract
This paper focuses on stable isotope labeling of drugs, in combination with mass spectrometry (MS)-based methods, to facilitate the recognition and identification of metabolites and the employment of stable isotope-labeled derivatization reagents (e.g., bis-trimethylsilylacetamide-d18) in the structure elucidation of metabolites from unlabeled drugs via gas-liquid chromatography-MS techniques. In both cases, it is the so-called isotope peak shift that permits generation of data useful for metabolite identification. Furthermore, judicious labeling of a drug permits characterization of drug-related species (metabolites) by MS-based recognition of isotope cluster signatures. Studies using stable isotope-labeled drugs are exemplified by work on aminopyrine and isopropylantipyrine metabolism; examples of the derivatization peak shift approach include those from studies of timolol and cyproheptadine.
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Baillie TA, Rettenmeier AW. Recent advances in the use of stable isotopes in drug metabolism research. J Clin Pharmacol 1986; 26:481-4. [PMID: 3734140 DOI: 10.1002/j.1552-4604.1986.tb03562.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Abstract
Stable-isotope techniques offer advantages over older methods in safety, sensitivity, specificity, and reduction in numbers of subjects required and analytic determinations for some types of pharmacology studies. In addition to their use as internal standards in gas chromatography-mass spectrometry analytic methods, stable isotopes have been successfully employed in studies of absorption, bioavailability, distribution, biotransformation, excretion, metabolite identification, time-dependent and dose-dependent pharmacokinetic changes, drug interactions, pharmacologic changes during pregnancy, mutagenicity, and teratogenicity.
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Moussard C, Alber D, Perruche C, Henry JC. The use of tritiated prostaglandins in metabolism studies. I: Evaluation of the kinetic isotope effect in the prostaglandin dehydrogenase reactions. PROSTAGLANDINS 1986; 31:489-500. [PMID: 3715057 DOI: 10.1016/0090-6980(86)90111-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Although numerous data exist concerning tritium kinetic isotope effect in enzymic reactions, little is related to the metabolism of tritiated prostaglandins. The present study reports an evaluation of the kinetic isotope effect which occurs during the oxidation of 15-hydroxyl group of tritium-labeled prostaglandins E2 and F2 alpha by the 15-hydroxyprostaglandin dehydrogenase and during the oxidation of 9-hydroxyl group of tritium-labeled prostaglandin F2 alpha by the 9-hydroxyprostaglandin dehydrogenase. The large kinetic isotope effect tends to limit the validity of the dehydrogenase assay using tritium-labeled prostaglandins as substrate. However these assays can be considered to be an indication of relative enzyme activity.
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Cronholm T, Norsten C. Gas chromatography-mass spectrometry of carboxylic acids in tissues as their tert.-butyldimethylsilyl derivatives. JOURNAL OF CHROMATOGRAPHY 1985; 344:1-9. [PMID: 4086531 DOI: 10.1016/s0378-4347(00)82001-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Krebs cycle and related acids were isolated from liver, pancreas and stomach of rats by pulverizing frozen tissue samples in liquid nitrogen with an aqueous solution of perchloric acid and methoxylamine hydrochloride. Perchloric acid and basic and neutral compounds were removed by ion-exchange chromatography on DEAE-Sephadex and SP-Sephadex columns. Phosphate was removed without loss of citrate by partition chromatography on Sephadex G-25 in a butanol--water system. Loss of acids during evaporation of water was prevented by keeping the temperature low and by addition of ammonia and tetrabutyl-ammonium bromide. tert.-Butyldimethylsilyl derivatives were prepared, purified by chromatography on a Sephadex LH-20 column and separated by gas chromatography on a non-polar capillary column. Recoveries in the procedure were above 45% for all acids except acetoacetate (25%). The mass spectrometric fragmentation of the methoxime-tert.-butyldimethylsilyl derivatives was studied by analysis of the derivatives of deuterated acids. The intense ions at M-57 present in all spectra appeared to contain all original hydrogen atoms. Thus, the method should be suitable for quantitation by isotope dilution and in metabolic studies with deuterated compounds.
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Gaudry D, Wantiez D, Metayer JP, Richard J. Simultaneous determination of oxprenolol and 2H6-labelled oxprenolol in human plasma by gas chromatography/mass spectrometry. BIOMEDICAL MASS SPECTROMETRY 1985; 12:269-73. [PMID: 3160404 DOI: 10.1002/bms.1200120605] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A gas chromatographic/mass spectrometric method for the specific determination of oxprenolol and 2H6-labelled oxprenolol when both are present in the same sample is described. After addition of 13C3-labelled oxprenolol as internal standard, plasma is alkalized and extracted by a mixture of dichloromethane and diethyl ether. The residue following evaporation of the organic phase is derivatized with heptafluorobutyric anhydride. Negative ion detection with N2O as reagent gas is used for the measurements at m/z 488, 491 and 494 for oxprenolol, the 13C3-labelled internal standard and 2H6-labelled oxprenolol, respectively. The precision and accuracy of the analytical method were investigated using samples containing both unlabelled and 2H6-labelled oxprenolol. The overall mean recovery (% +/- SD, n = 70) in the concentration range 20-1500 nmol l-1 (around 6-450 ng ml-1 of the hydrochloride salts) was 100.6 +/- 3.3 and 101.0 +/- 3.5 for oxprenolol and 2H6-labelled oxprenolol, respectively. The limit of quantification was around 20 nmol l-1 for both compounds.
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Gelijkens CF, Van Peer A, Lenoir H, Knaeps A, Woestenborghs R, Heykants J. The use and limitations of deuterated lorcainide in metabolism and pharmacokinetic studies. BIOMEDICAL MASS SPECTROMETRY 1985; 12:38-42. [PMID: 3157409 DOI: 10.1002/bms.1200120108] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Lorcainide, a new antiarrhythmic agent currently undergoing clinical trial, has been pentadeuterated and the usefulness of this labelled compound in pharmacokinetic and metabolism studies has been investigated in dogs. Specific analytical methods based on capillary gas chromatography/mass spectrometry (GC/MS) were developed for quantitative and qualitative analysis of plasma and urine samples. Following oral administration of an equimolar mixture of 5 : 5 mg of (2H0/2H5)lorcainide, eight major metabolites were rapidly identified in urine by the ion cluster technique. Quantitative analysis of (2H0/2H5)lorcainide in plasma and urine indicated an enhanced systematic availability of the deuterated compound, probably due to a secondary isotope effect. According to these findings in the dog, the use of deuterated lorcainide in human bioavailability and metabolism studies is probably of limited value.
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De Leenheer AP, Lefevere MF, Lambert WE, Colinet ES. Isotope-dilution mass spectrometry in clinical chemistry. Adv Clin Chem 1985; 24:111-61. [PMID: 3911749 DOI: 10.1016/s0065-2423(08)60272-3] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Browne TR, Evans JE, Szabo GK, Evans BA, Greenblatt DJ, Schumacher GE. Studies with stable isotopes I: Changes in phenytoin pharmacokinetics and biotransformation during monotherapy. J Clin Pharmacol 1985; 25:43-50. [PMID: 3973063 DOI: 10.1002/j.1552-4604.1985.tb02799.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Six patients were given tracer doses of 13C15N2-phenytoin (PHT) before and four and 12 weeks after beginning monotherapy. The following significant (P less than .05) changes occurred during monotherapy: (1) Apparent (from tracer doses) PHT total clearance by linear method decreased; (2) apparent PHT elimination half-life increased; (3) apparent mean PHT serum concentration per unit dose increased; (4) apparent rate of excretion of p-hydroxyphenyl-phenylhydantoin (p-HPPH) decreased; (5) apparent rate of excretion of PHT dihydrodiol increased; and (6) apparent PHT total clearance and elimination half-life and apparent p-HPPH rate of excretion were dose dependent. Phenytoin apparent pharmacokinetic and biotransformation values undergo a typical series of changes after beginning monotherapy at typical dosing rates, because PHT's dose-dependent pharmacokinetics result in differing apparent values as the serum concentration rises to steady state. Stable isotope methods are particularly suitable for investigating such phenomena.
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Chapter 27. Stable Isotopes in Drug Metabolism and Disposition. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 1984. [DOI: 10.1016/s0065-7743(08)60703-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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Hoffman DJ, Porter WR. Resolution of valproic acid from deuterated analogues and their quantitation in plasma using capillary gas chromatography. JOURNAL OF CHROMATOGRAPHY 1983; 276:301-9. [PMID: 6415082 DOI: 10.1016/s0378-4347(00)85096-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Quantitation of valproic acid and a deuterated analogue in the same plasma sample by capillary gas chromatography without mass spectrometry was illustrated. Specificity was accomplished solely with a 60 m X 0.25 mm fused silica WCOT column coated with OV-351. A hexadeutero and two tetradeutero analogues of valproic acid had resolutions of at least 1.2 from valproic acid. Plasma samples were extracted with carbon tetrachloride following the addition of 2-ethylhexanoic acid as the internal standard. The method is sensitive to at least 0.5 microgram/ml and provides the capability of conducting absolute bioavailability and pulsed dosing studies with deuterated drug analogues without a mass spectrometer. The technique was applied to the analysis of plasma samples from dogs simultaneously administered valproic acid and a deuterated analogue.
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Street JM, Trafford DJ, Makin HL. The quantitative estimation of bile acids and their conjugates in human biological fluids. J Lipid Res 1983. [DOI: 10.1016/s0022-2275(20)37955-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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