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Erhardt P, Bachmann K, Birkett D, Boberg M, Bodor N, Gibson G, Hawkins D, Hawksworth G, Hinson J, Koehler D, Kress B, Luniwal A, Masumoto H, Novak R, Portoghese P, Sarver J, Serafini MT, Trabbic C, Vermeulen N, Wrighton S. Glossary and tutorial of xenobiotic metabolism terms used during small molecule drug discovery and development (IUPAC Technical Report). PURE APPL CHEM 2021. [DOI: 10.1515/pac-2018-0208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Abstract
This project originated more than 15 years ago with the intent to produce a glossary of drug metabolism terms having definitions especially applicable for use by practicing medicinal chemists. A first-draft version underwent extensive beta-testing that, fortuitously, engaged international audiences in a wide range of disciplines involved in drug discovery and development. It became clear that the inclusion of information to enhance discussions among this mix of participants would be even more valuable. The present version retains a chemical structure theme while expanding tutorial comments that aim to bridge the various perspectives that may arise during interdisciplinary communications about a given term. This glossary is intended to be educational for early stage researchers, as well as useful for investigators at various levels who participate on today’s highly multidisciplinary, collaborative small molecule drug discovery teams.
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Affiliation(s)
- Paul Erhardt
- Center for Drug Design and Development , University of Toledo , Toledo , Ohio , USA
| | | | - Donald Birkett
- Department of Clinical Pharmacology , Flinders University , Adelaide , Australia (now Emeritus), (TGM)
| | - Michael Boberg
- Metabolism and Isotope Chemistry , Bayer , AG , Germany (now undetermined), (TGM)
| | - Nicholas Bodor
- Center for Drug Discovery , University of Florida , Belle Glade , FL , USA (now Emeritus Grad Res Prof/CEO Bodor Labs), (TGM)
| | - Gordon Gibson
- School of Biomedical and Life Sciences, University of Surrey , Surrey , UK (now deceased), (TGM)
| | - David Hawkins
- Huntingdon Life Sciences , Huntingdon , UK (now retired), (TGM)
| | - Gabrielle Hawksworth
- Department of Medicine and Therapeutics , University Aberdeen , Aberdeen , UK (now deceased), (TGM)
| | - Jack Hinson
- Division of Toxicology , University Arkansas for Medical Sciences , Little Rock , Arkansas , USA (now Emeritus Dist Prof), (TGM)
| | - Daniel Koehler
- Department of Pharmacology , University of Toledo , Toledo , Ohio , USA, (ST)
| | - Brian Kress
- Department of Medicinal and Biological Chemistry , University of Toledo , Toledo , Ohio , USA, (ST)
| | | | - Hiroshi Masumoto
- Drug Metabolism , Daiichi Pharm. Corp., Ltd. , Chuo , Tokyo , Japan (now retired), (TGM)
| | - Raymond Novak
- Institute of Environmental Health Science, Wayne State University , Detroit , Michigan , USA (now undetermined), (TGM)
| | - Phillip Portoghese
- Department of Medicinal Chemistry , University of Minnesota , Minneapolis , Minnesota , USA (now same), (TGM)
| | - Jeffrey Sarver
- Department of Pharmacology , University of Toledo , Toledo , Ohio , USA, (ST)
| | - M. Teresa Serafini
- Department of Pharmacokinetics and Drug Metabolism , Laboratories Dr. Esteve, S.A. , Barcelona , Spain (now Head Early ADME), (TGM)
| | | | - Nico Vermeulen
- Department of Pharmacochemistry , Vrije University , Amsterdam , Netherlands (now Emeritus Section Molecular Toxicology), (TGM)
| | - Steven Wrighton
- Eli Lilly, Inc. , Indianapolis , Indiana , USA (now retired), (TGM)
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Hum NR, Martin KA, Malfatti MA, Haack K, Buchholz BA, Loots GG. Tracking Tumor Colonization in Xenograft Mouse Models Using Accelerator Mass Spectrometry. Sci Rep 2018; 8:15013. [PMID: 30302019 PMCID: PMC6178347 DOI: 10.1038/s41598-018-33368-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 09/24/2018] [Indexed: 12/12/2022] Open
Abstract
Here we introduce an Accelerator Mass Spectrometry (AMS)-based high precision method for quantifying the number of cancer cells that initiate metastatic tumors, in xenograft mice. Quantification of 14C per cell prior to injection into animals, and quantification of 14C in whole organs allows us to extrapolate the number of cancer cells available to initiate metastatic tumors. The 14C labeling was optimized such that 1 cancer cell was detected among 1 million normal cells. We show that ~1–5% of human cancer cells injected into immunodeficient mice form subcutaneous tumors, and even fewer cells initiate metastatic tumors. Comparisons of metastatic site colonization between a highly metastatic (PC3) and a non-metastatic (LnCap) cell line showed that PC3 cells colonize target tissues in greater quantities at 2 weeks post-delivery, and by 12 weeks post-delivery no 14C was detected in LnCap xenografts, suggesting that all metastatic cells were cleared. The 14C-signal correlated with the presence and the severity of metastatic tumors. AMS measurements of 14C-labeled cells provides a highly-sensitive, quantitative assay to experimentally evaluate metastasis and colonization of target tissues in xenograft mouse models. This approach can potentially be used to evaluate tumor aggressiveness and assist in making informed decisions regarding treatment.
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Affiliation(s)
- Nicholas R Hum
- Lawrence Livermore National Laboratory, Physical and Life Sciences Directorate, Livermore, CA, USA
| | - Kelly A Martin
- Lawrence Livermore National Laboratory, Physical and Life Sciences Directorate, Livermore, CA, USA.,Georgetown University, Department of Biochemistry & Molecular Biology, Washington, DC, USA
| | - Michael A Malfatti
- Lawrence Livermore National Laboratory, Physical and Life Sciences Directorate, Livermore, CA, USA
| | - Kurt Haack
- Lawrence Livermore National Laboratory, Physical and Life Sciences Directorate, Livermore, CA, USA
| | - Bruce A Buchholz
- Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Gabriela G Loots
- Lawrence Livermore National Laboratory, Physical and Life Sciences Directorate, Livermore, CA, USA. .,UC Merced, School of Natural Sciences, Merced, CA, USA.
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Evaluation of cAMS for 14C microtracer ADME studies: opportunities to change the current drug development paradigm. Bioanalysis 2018; 10:321-339. [DOI: 10.4155/bio-2017-0216] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Aim: Although regulatory guidances require human metabolism information of drug candidates early in the development process, the human mass balance study (or hADME study), is performed relatively late. hADME studies typically involve the administration of a 14C-radiolabelled drug where biological samples are measured by conventional scintillation counting analysis. Another approach is the administration of therapeutic doses containing a 14C-microtracer followed by accelerator mass spectrometry (AMS) analysis, enabling hADME studies completion much earlier. Consequently, there is an opportunity to change the current drug development paradigm. Materials & methods: To evaluate the applicability of the MICADAS–cAMS method, we successfully performed: the validation of MICADAS–cAMS for radioactivity quantification in biomatrices and, a rat ADME study, where the conventional methodology was assessed against a microtracer MICADAS–cAMS approach. Results & discussion: Combustion AMS (cAMS) technology is applicable to microtracer studies. A favorable opinion from EMA to complete the hADME in a Phase I setting was received, opening the possibilities to change drug development.
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McCartt AD, Ognibene TJ, Bench G, Turteltaub KW. Quantifying Carbon-14 for Biology Using Cavity Ring-Down Spectroscopy. Anal Chem 2016; 88:8714-9. [PMID: 27458740 PMCID: PMC5257295 DOI: 10.1021/acs.analchem.6b02054] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A cavity ring-down spectroscopy (CRDS) instrument was developed using mature, robust hardware for the measurement of carbon-14 in biological studies. The system was characterized using carbon-14 elevated glucose samples and returned a linear response up to 387 times contemporary carbon-14 concentrations. Carbon-14 free and contemporary carbon-14 samples with varying carbon-13 concentrations were used to assess the method detection limit of approximately one-third contemporary carbon-14 levels. Sources of inaccuracies are presented and discussed, and the capability to measure carbon-14 in biological samples is demonstrated by comparing pharmacokinetics from carbon-14 dosed guinea pigs analyzed by both CRDS and accelerator mass spectrometry. The CRDS approach presented affords easy access to powerful carbon-14 tracer techniques that can characterize complex biochemical systems.
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Affiliation(s)
- A Daniel McCartt
- Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory , 7000 East Avenue, Livermore, California 94550, United States
| | - Ted J Ognibene
- Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory , 7000 East Avenue, Livermore, California 94550, United States
| | - Graham Bench
- Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory , 7000 East Avenue, Livermore, California 94550, United States
| | - Kenneth W Turteltaub
- Biology and Biotechnology Division, Lawrence Livermore National Laboratory , 7000 East Avenue, Livermore, California 94550, United States
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Opportunities in low-level radiocarbon microtracing: applications and new technology. Future Sci OA 2015; 2:FSO74. [PMID: 28031933 PMCID: PMC5137946 DOI: 10.4155/fso.15.74] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 08/20/2015] [Indexed: 12/14/2022] Open
Abstract
14C-radiolabeled (radiocarbon) drug studies are central to defining the disposition of therapeutics in clinical development. Concerns over radiation, however, have dissuaded investigators from conducting these studies as often as their utility may merit. Accelerator mass spectrometry (AMS), originally designed for carbon dating and geochronology, has changed the outlook for in-human radiolabeled testing. The high sensitivity of AMS affords human clinical testing with vastly reduced radiative (microtracing) and chemical exposures (microdosing). Early iterations of AMS were unsuitable for routine biomedical use due to the instruments' large size and associated per sample costs. The situation is changing with advances in the core and peripheral instrumentation. We review the important milestones in applied AMS research and recent advances in the core technology platform. We also look ahead to an entirely new class of 14C detection systems that use lasers to measure carbon dioxide in small gas cells.
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Cho DY, Bae SH, Shon JH, Bae SK. High-sensitive LC-MS/MS method for the simultaneous determination of mirodenafil and its major metabolite, SK-3541, in human plasma: Application to microdose clinical trials of mirodenafil. J Sep Sci 2013; 36:840-8. [DOI: 10.1002/jssc.201200919] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Revised: 11/01/2012] [Accepted: 11/08/2012] [Indexed: 11/08/2022]
Affiliation(s)
- Doo-Yeoun Cho
- Department of Family Practice & Community Health; Ajou University School of Medicine; Suwon Korea
| | - Soo Hyeon Bae
- College of Pharmacy; The Catholic University of Korea; Bucheon Korea
| | - Ji-Hong Shon
- Department of Clinical Pharmacology and Clinical Trial Center; Inje University Busan Paik Hospital; Busan Korea
| | - Soo Kyung Bae
- College of Pharmacy; The Catholic University of Korea; Bucheon Korea
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Penner N, Xu L, Prakash C. Radiolabeled Absorption, Distribution, Metabolism, and Excretion Studies in Drug Development: Why, When, and How? Chem Res Toxicol 2012; 25:513-31. [DOI: 10.1021/tx300050f] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Natalia Penner
- Department
of Drug Metabolism and Preclinical Safety, Biogen Idec, Cambridge, Massachusetts 02142
| | - Lin Xu
- Department
of Drug Metabolism and Preclinical Safety, Biogen Idec, Cambridge, Massachusetts 02142
| | - Chandra Prakash
- Department
of Drug Metabolism and Preclinical Safety, Biogen Idec, Cambridge, Massachusetts 02142
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Bae SK, Shon JH. Microdosing studies using accelerated mass spectrometry as exploratory investigational new drug trials. Arch Pharm Res 2011; 34:1789-98. [DOI: 10.1007/s12272-011-1102-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Accepted: 08/24/2011] [Indexed: 11/24/2022]
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Wagner CC, Simpson M, Zeitlinger M, Bauer M, Karch R, Abrahim A, Feurstein T, Schütz M, Kletter K, Müller M, Lappin G, Langer O. A combined accelerator mass spectrometry-positron emission tomography human microdose study with 14C- and 11C-labelled verapamil. Clin Pharmacokinet 2011; 50:111-20. [PMID: 21142292 DOI: 10.2165/11537250-000000000-00000] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
BACKGROUND AND OBJECTIVE In microdose studies, the pharmacokinetic profile of a drug in blood after administration of a dose up to 100 μg is measured with sensitive analytical techniques, such as accelerator mass spectrometry (AMS). As most drugs exert their effect in tissue rather than blood, methodology is needed for extending pharmacokinetic analysis to different tissue compartments. In the present study, we combined, for the first time, AMS analysis with positron emission tomography (PET) in order to determine the pharmacokinetic profile of the model drug verapamil in plasma and brain of humans. In order to assess pharmacokinetic dose linearity of verapamil, data were acquired and compared after administration of an intravenous microdose and after an intravenous microdose administered concomitantly with an oral therapeutic dose. METHODS Six healthy male subjects received an intravenous microdose [0.05 mg] (period 1) and an intravenous microdose administered concomitantly with an oral therapeutic dose [80 mg] of verapamil (period 2) in a randomized, crossover, two-period study design. The intravenous dose was a mixture of (R/S)-[14C]verapamil and (R)-[11C]verapamil and the oral dose was unlabelled racaemic verapamil. Brain distribution of radioactivity was measured with PET whereas plasma pharmacokinetics of (R)- and (S)-verapamil were determined with AMS. PET data were analysed by pharmacokinetic modelling to estimate the rate constants for transfer (k) of radioactivity across the blood-brain barrier. RESULTS Most pharmacokinetic parameters of (R)- and (S)-verapamil as well as parameters describing exchange of radioactivity between plasma and brain (influx rate constant [K(1)] = 0.030 ± 0.003 and 0.031 ± 0.005 mL/mL/min and efflux rate constant [k(2)] = 0.099 ± 0.006 and 0.095 ± 0.008 min-1 for period 1 and 2, respectively) were not statistically different between the two periods although there was a trend for nonlinear pharmacokinetics for the (R)-enantiomer. On the other hand, all pharmacokinetic parameters (except for the terminal elimination half-life [t1/2;)]) differed significantly between the (R)- and (S)-enantiomers for both periods. The maximum plasma concentration (C(max)), area under the plasma concentration-time curve (AUC) from 0 to 24 hours (AUC(24)) and AUC from time zero to infinity (AUC(∞)) were higher and the total clearance (CL), volume of distribution (V(d)) and volume of distribution at steady state (V(ss)) were lower for the (R)- than for the (S)-enantiomer. CONCLUSION Combining AMS and PET microdosing allows long-term pharmacokinetic data along with information on drug tissue distribution to be acquired in the same subjects thus making it a promising approach to maximize data output from a single clinical study.
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Affiliation(s)
- Claudia C Wagner
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
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Abstract
Anne-Françoise Aubry is Director of Bioanalytical Sciences at Bristol-Myers Squibb Co., leading a team in developing bioanalytical methods for early development drug candidates in support of toxicology and clinical studies. Her main research interests are high-speed, high-resolution LC and new approaches for LC–MS/MS drug bioanalysis in regulated laboratories. Anne Aubry is on the executive board of the Eastern Analytical Symposium and on the organizing committee of the Applied Pharmaceutical Analysis and Chemical and Pharmaceutical Structure Analysis (Shanghai 2011) conferences. The challenges of developing and running low pg/ml LC–MS/MS bioanalytical assays in a regulated laboratory are reviewed. The practical problems encountered in implementing ultrasensitive assays are less in reaching a suitable sensitivity on the instrument than in implementing procedures to control losses and contamination, eliminate matrix interferences and ensure assay robustness so that the assay can be validated to industry standards. Solutions to these problems can be found in each of the three facets of the bioanalytical assay: the sample preparation, the chromatographic separation and the mass spectrometric detection. The key to developing an ultrasensitive assay is to optimize each of these elements. Progress in MS instrumentation has been essential in our ability to reach the low pg/ml limits.
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Gao L, Li J, Kasserra C, Song Q, Arjomand A, Hesk D, Chowdhury SK. Precision and Accuracy in the Quantitative Analysis of Biological Samples by Accelerator Mass Spectrometry: Application in Microdose Absolute Bioavailability Studies. Anal Chem 2011; 83:5607-16. [DOI: 10.1021/ac2006284] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | | | | | - Qi Song
- Accium BioSciences, Inc., Seattle, Washington 98122, United States
| | - Ali Arjomand
- Accium BioSciences, Inc., Seattle, Washington 98122, United States
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Adler S, Basketter D, Creton S, Pelkonen O, van Benthem J, Zuang V, Andersen KE, Angers-Loustau A, Aptula A, Bal-Price A, Benfenati E, Bernauer U, Bessems J, Bois FY, Boobis A, Brandon E, Bremer S, Broschard T, Casati S, Coecke S, Corvi R, Cronin M, Daston G, Dekant W, Felter S, Grignard E, Gundert-Remy U, Heinonen T, Kimber I, Kleinjans J, Komulainen H, Kreiling R, Kreysa J, Leite SB, Loizou G, Maxwell G, Mazzatorta P, Munn S, Pfuhler S, Phrakonkham P, Piersma A, Poth A, Prieto P, Repetto G, Rogiers V, Schoeters G, Schwarz M, Serafimova R, Tähti H, Testai E, van Delft J, van Loveren H, Vinken M, Worth A, Zaldivar JM. Alternative (non-animal) methods for cosmetics testing: current status and future prospects-2010. Arch Toxicol 2011; 85:367-485. [PMID: 21533817 DOI: 10.1007/s00204-011-0693-2] [Citation(s) in RCA: 358] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Accepted: 03/03/2011] [Indexed: 01/09/2023]
Abstract
The 7th amendment to the EU Cosmetics Directive prohibits to put animal-tested cosmetics on the market in Europe after 2013. In that context, the European Commission invited stakeholder bodies (industry, non-governmental organisations, EU Member States, and the Commission's Scientific Committee on Consumer Safety) to identify scientific experts in five toxicological areas, i.e. toxicokinetics, repeated dose toxicity, carcinogenicity, skin sensitisation, and reproductive toxicity for which the Directive foresees that the 2013 deadline could be further extended in case alternative and validated methods would not be available in time. The selected experts were asked to analyse the status and prospects of alternative methods and to provide a scientifically sound estimate of the time necessary to achieve full replacement of animal testing. In summary, the experts confirmed that it will take at least another 7-9 years for the replacement of the current in vivo animal tests used for the safety assessment of cosmetic ingredients for skin sensitisation. However, the experts were also of the opinion that alternative methods may be able to give hazard information, i.e. to differentiate between sensitisers and non-sensitisers, ahead of 2017. This would, however, not provide the complete picture of what is a safe exposure because the relative potency of a sensitiser would not be known. For toxicokinetics, the timeframe was 5-7 years to develop the models still lacking to predict lung absorption and renal/biliary excretion, and even longer to integrate the methods to fully replace the animal toxicokinetic models. For the systemic toxicological endpoints of repeated dose toxicity, carcinogenicity and reproductive toxicity, the time horizon for full replacement could not be estimated.
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Affiliation(s)
- Sarah Adler
- Centre for Documentation and Evaluation of Alternatives to Animal Experiments (ZEBET), Federal Institute for Risk Assessment (BfR), Berlin, Germany
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Ma S, Chowdhury SK. Analytical Strategies for Assessment of Human Metabolites in Preclinical Safety Testing. Anal Chem 2011; 83:5028-36. [DOI: 10.1021/ac200349g] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Nedderman AN, Dear GJ, North S, Obach RS, Higton D. From definition to implementation: a cross-industry perspective of past, current and future MIST strategies. Xenobiotica 2011; 41:605-22. [DOI: 10.3109/00498254.2011.562330] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Accelerator mass spectrometry-enabled studies: current status and future prospects. Bioanalysis 2011; 2:519-41. [PMID: 20440378 DOI: 10.4155/bio.09.188] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Accelerator mass spectrometry is a detection platform with exceptional sensitivity compared with other bioanalytical platforms. Accelerator mass spectrometry (AMS) is widely used in archeology for radiocarbon dating applications. Early exploration of the biological and pharmaceutical applications of AMS began in the early 1990s. AMS has since demonstrated unique problem-solving ability in nutrition science, toxicology and pharmacology. AMS has also enabled the development of new applications, such as Phase 0 microdosing. Recent development of AMS-enabled applications has transformed this novelty research instrument to a valuable tool within the pharmaceutical industry. Although there is now greater awareness of AMS technology, recognition and appreciation of the range of AMS-enabled applications is still lacking, including study-design strategies. This review aims to provide further insight into the wide range of AMS-enabled applications. Examples of studies conducted over the past two decades will be presented, as well as prospects for the future of AMS.
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Sensitivity and proportionality assessment of metabolites from microdose to high dose in rats using LC-MS/MS. Bioanalysis 2011; 2:407-19. [PMID: 21083251 DOI: 10.4155/bio.10.10] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND The objective of this study was to evaluate the sensitivity requirement for LC-MS/MS as an analytical tool to characterize metabolites in plasma and urine at microdoses in rats and to investigate proportionality of metabolite exposure from a microdose of 1.67 µg/kg to a high dose of 5000 µg/kg for atorvastatin, ofloxacin, omeprazole and tamoxifen. RESULTS Only the glucuronide metabolite of ofloxacin, the hydroxylation metabolite of omeprazole and the hydration metabolite of tamoxifen were characterized in rat plasma at microdose by LC-MS/MS. The exposure of detected metabolites of omeprazole and tamoxifen appeared to increase in a nonproportional manner with increasing doses. Exposure of ortho- and para-hydroxyatorvastatin, but not atorvastatin and lactone, increased proportionally with increasing doses. CONCLUSION LC-MS/MS has demonstrated its usefulness for detecting and characterizing the major metabolites in plasma and urine at microdosing levels in rats. The exposure of metabolites at microdose could not simply be used to predict their exposure at higher doses.
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Yu H, Bischoff D, Tweedie D. Challenges and solutions to metabolites in safety testing: impact of the International Conference on Harmonization M3(R2) guidance. Expert Opin Drug Metab Toxicol 2010; 6:1539-49. [DOI: 10.1517/17425255.2010.530655] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Stewart BJ, Navid A, Turteltaub KW, Bench G. Yeast dynamic metabolic flux measurement in nutrient-rich media by HPLC and accelerator mass spectrometry. Anal Chem 2010; 82:9812-7. [PMID: 21062031 DOI: 10.1021/ac102065f] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Metabolic flux, the flow of metabolites through networks of enzymes, represents the dynamic productive output of cells. Improved understanding of intracellular metabolic fluxes will enable targeted manipulation of metabolic pathways of medical and industrial importance to a greater degree than is currently possible. Flux balance analysis (FBA) is a constraint-based approach to modeling metabolic fluxes, but its utility is limited by a lack of experimental measurements. Incorporation of experimentally measured fluxes as system constraints will significantly improve the overall accuracy of FBA. We applied a novel, two-tiered approach in the yeast Saccharomyces cerevisiae to measure nutrient consumption rates (extracellular fluxes) and a targeted intracellular flux using a (14)C-labeled precursor with HPLC separation and flux quantitation by accelerator mass spectrometry (AMS). The use of AMS to trace the intracellular fate of (14)C-glutamine allowed the calculation of intracellular metabolic flux through this pathway, with glutathione as the metabolic end point. Measured flux values provided global constraints for the yeast FBA model which reduced model uncertainty by more than 20%, proving the importance of additional constraints in improving the accuracy of model predictions and demonstrating the use of AMS to measure intracellular metabolic fluxes. Our results highlight the need to use intracellular fluxes to constrain the models. We show that inclusion of just one such measurement alone can reduce the average variability of model predicted fluxes by 10%.
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Affiliation(s)
- Benjamin J Stewart
- Lawrence Livermore National Laboratory, Center for Accelerator Mass Spectrometry, 7000 East Avenue P.O. Box 808, L-397 Livermore, California 94551, USA.
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Accelerator mass spectrometry measurement of intracellular concentrations of active drug metabolites in human target cells in vivo. Clin Pharmacol Ther 2010; 88:796-800. [PMID: 20981003 DOI: 10.1038/clpt.2010.188] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Accelerator mass spectrometry (AMS) is an ultrasensitive technique to detect radiolabeled compounds. We administered a microdose (100 µg) of (14)C-labeled zidovudine (ZDV) with or without a standard unlabeled dose (300 mg) to healthy volunteers. Intracellular ZDV-triphosphate (ZDV-TP) concentration was measured using AMS and liquid chromatography-tandem mass spectrometry (LC/MS/MS). AMS analysis yielded excellent concordance with LC/MS/MS and was 30,000-fold more sensitive. The kinetics of intracellular ZDV-TP formation changed several-fold over the dose range studied (100 µg-300 mg). AMS holds promise as a tool for quantifying intracellular drug metabolites and other biomediators in vivo.
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Kiffe M, Schmid DG, Bruin GJM. Radioactivity Detectors for High-Performance Liquid Chromatography in Drug Metabolism Studies. J LIQ CHROMATOGR R T 2010. [DOI: 10.1080/10826070802126254] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Michael Kiffe
- a Novartis Pharma AG, NIBR/Metabolism & Pharmacokinetics , CH-4002 Basel, Switzerland
| | - Dietmar G. Schmid
- b Novartis Pharma AG, DMPK/Drug Metabolism and Bioanalytics , CH-4002 Basel, Switzerland
| | - Gerard J. M. Bruin
- c Novartis Pharma AG, Global Pharmacokinetics and Pharmacodynamics , CH-4002 Basel, Switzerland
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Early human ADME using microdoses and microtracers: bioanalytical considerations. Bioanalysis 2010; 2:441-54. [DOI: 10.4155/bio.10.8] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Quantitative assessment of metabolites of drug candidates in early-phase clinical development presents an analytical challenge when methods, standards and assays are not yet available. Radioisotopic labeling, principally with radiocarbon (14C), is the preferred method for discovering and quantifying the absolute yields of metabolites in the absence of reference material or a priori knowledge of the human metabolism. However, the detection of 14C is inefficient by decay counting methods and, as a result, high radiological human 14C-doses had been needed to assure sensitive detection of metabolites over time. High radiological doses and the associated costs have been a major obstacle to the routine (and early) use of 14C despite the recognized advantages of a 14C-tracer for quantifying drug metabolism and disposition. Accelerator mass spectrometry eliminates this long-standing problem by reducing radioactivity levels while delivering matrix-independent quantitation to attomole levels of sensitivity in small samples or fractionated isolates. Accelerator mass spectrometry and trace 14C-labeled drugs are now used to obtain early insights into the human metabolism of a drug candidate in ways that were not previously practical. With this article we describe some of our empirically based approaches for regualted bioanalysis and offer perspectives on current applications and opportunities for the future.
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Creton S, Billington R, Davies W, Dent MP, Hawksworth GM, Parry S, Travis KZ. Application of toxicokinetics to improve chemical risk assessment: implications for the use of animals. Regul Toxicol Pharmacol 2009; 55:291-9. [PMID: 19665509 DOI: 10.1016/j.yrtph.2009.08.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2009] [Revised: 07/31/2009] [Accepted: 08/03/2009] [Indexed: 11/30/2022]
Abstract
While toxicokinetics has become an integral part of pharmaceutical safety assessment over the last two decades, its use in the chemical industry is relatively new. However, it is recognised as a potentially important tool in human health risk assessment and recent initiatives have advocated greater application of toxicokinetics as part of an improved assessment strategy for crop protection chemicals that could offer greater efficiency, use fewer animals and provide better data for risk assessment purposes. To explore the potential scientific and animal welfare benefits of increased use of toxicokinetic data across the chemical industry, an international workshop was held in 2008. Experts from a wide range of chemical industry sectors, including industrial chemicals, agrochemicals and consumer products, participated in the meeting as well as representatives from relevant regulatory authorities. Pharmaceutical industry experts were also invited, in order to share experiences from the extensive use of toxicokinetics in drug development. Given that increased generation of toxicokinetic data could potentially result in an increased number of animals undergoing testing, technologies and strategies to reduce and refine animal use for this purpose were also considered. This paper outlines and expands upon the key themes that emerged from the workshop.
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Affiliation(s)
- Stuart Creton
- National Centre for the Replacement, Refinement and Reduction of Animals in Research, London W1B 1AL, UK.
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24
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Lappin G, Garner RC. The utility of microdosing over the past 5 years. Expert Opin Drug Metab Toxicol 2009; 4:1499-506. [PMID: 19040326 DOI: 10.1517/17425250802531767] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Microdosing studies (human Phase 0) are used to select drug candidates for Phase I clinical trials on the basis of their pharmacokinetic properties, using subpharmacologic doses (maximum 100 microg). There are questions as to whether pharmacokinetic data obtained at these low doses will predict those at the clinically relevant dose. OBJECTIVE To review the current literature on microdosing and assess how well microdose data have predicted the pharmacokinetics obtained at a therapeutic dose. METHODS All data published in the peer reviewed literature comparing pharmacokinetics at a microdose with a therapeutic dose were reviewed, excluding those studies aimed at imaging. CONCLUSIONS Of the 18 drugs reported, 15 demonstrated linear pharmacokinetics within a factor of 2 between a microdose and a therapeutic dose. Therefore, data that support the utility of microdosing are beginning to emerge.
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Affiliation(s)
- Graham Lappin
- Xceleron Ltd, The Biocentre, Innovation Way, York, YO10 5NY, UK.
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25
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Chapter 22 Safety Testing of Drug Metabolites. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 2009. [DOI: 10.1016/s0065-7743(09)04422-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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26
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Lappin G, Stevens L. Biomedical accelerator mass spectrometry: recent applications in metabolism and pharmacokinetics. Expert Opin Drug Metab Toxicol 2008; 4:1021-33. [DOI: 10.1517/17425255.4.8.1021] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Microdosing assessment to evaluate pharmacokinetics and drug metabolism in rats using liquid chromatography-tandem mass spectrometry. Pharm Res 2008; 25:1572-82. [PMID: 18299965 DOI: 10.1007/s11095-008-9555-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2007] [Accepted: 02/04/2008] [Indexed: 10/22/2022]
Abstract
PURPOSE To evaluate the sensitivity requirement for LC-MS/MS as an analytical tool to support human microdosing study with sub-pharmacological dose, investigate proportionality of pharmacokinetics from the microdose to therapeutic human equivalent doses in rats and characterize circulating metabolites in rats administered with the microdose. MATERIALS AND METHODS Five drugs of antipyrine, metoprolol, carbamazepine, digoxin and atenolol were administered orally to male Sprague-Dawley rats at 0.167, 1.67, 16.7, 167 and 1,670 microg/kg doses. Plasma samples were extracted using either solid phase extraction or liquid-liquid extraction, and analyzed using LC-MS/MS. RESULTS Using 100 microl of plasma sample, the lower limit of quantitation for antipyrine (10 pg/ml), carbamazepine (1 pg/ml), metoprolol (5 pg/ml), atenolol (20 pg/ml), and digoxin (5 pg/ml) were achieved using an API 5000. Proportional pharmacokinetics were observed from 0.167 microg/kg to 1,670 microg/kg for antipyrine and carbamazepine and from 1.67 to 1,670 microg/kg for atenolol and digoxin, while metoprolol exhibited a non-proportional pharmacokinetics relationship. Several metabolites of carbamazepine were characterized in plasma from rats dosed at 1.67 mug/kg using LC-MS/MS. CONCLUSIONS This study has shown the promise of sensitive LC-MS/MS method to support microdose pharmacokinetics and drug metabolism studies in human.
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Baillie TA. Metabolism and Toxicity of Drugs. Two Decades of Progress in Industrial Drug Metabolism. Chem Res Toxicol 2007; 21:129-37. [DOI: 10.1021/tx7002273] [Citation(s) in RCA: 158] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Thomas A. Baillie
- Merck Research Laboratories, Department of Drug Metabolism and Pharmacokinetics WP75B-330, Sumneytown Pike, West Point, Pennsylvania 19486-0004
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Kiffe M, Nufer R, Trunzer M, Graf D. Cytostar-T plates—A valid alternative for microplate scintillation counting of low radioactivity in combination with high-performance liquid chromatography in drug metabolism studies? J Chromatogr A 2007; 1157:65-72. [PMID: 17466316 DOI: 10.1016/j.chroma.2007.04.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2007] [Revised: 04/02/2007] [Accepted: 04/05/2007] [Indexed: 11/29/2022]
Abstract
The determination of radioactivity from metabolite patterns in ADME studies in a low radioactivity/residue situation is a very challenging process requiring special technologies. The recently introduced TopCount technology uses LumaPlates for the collection of the column effluent after HPLC separation to subsequently determine radioactivity for the generation of the metabolite profile. Samples from drug metabolism studies were used to compare the performance of the widely used LumaPlates with Cytostar-T plates regarding sensitivity and recovery of metabolites for structure elucidation by MS. Optimized counting parameters were investigated for the Cytostar-T plates. This had led to higher sensitivity and therefore to a preferential signal to noise ratio. Metabolites which were collected into Cytostar-T instead of LumaPlates could be easily recovered and directly used for structure elucidation by MS. The full scan mass spectra of recovered metabolites showed higher quality allowing the characterization of metabolites without any further sample pre-treatment. This is a major advantage which could further speed-up the structure elucidation process of metabolites in complex biological matrices.
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Affiliation(s)
- Michael Kiffe
- Novartis Pharma AG, Metabolism and pharmacokinetics (MAP), WSJ-360.2.02, CH-4002 Basel, Switzerland.
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Lappin G, Rowland M, Garner RC. The use of isotopes in the determination of absolute bioavailability of drugs in humans. Expert Opin Drug Metab Toxicol 2006; 2:419-27. [PMID: 16863443 DOI: 10.1517/17425255.2.3.419] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Absolute bioavailability studies in humans are not routinely performed as part of the drug registration process. They tend to be reasonably demanding, not least because toxicology data are required to support intravenous administration of a drug. Moreover, the classical crossover design of an absolute bioavailability study can suffer from artefacts caused by concentration-dependent pharmacokinetics. Many of the problems associated with absolute bioavailability studies can be alleviated using isotopically labelled drugs. Stable isotopes have been used in the performance of absolute bioavailability studies in humans for > 30 years. More recently, the advantages of using radiolabelled drugs have been expanded by using the ultrasensitive technology of accelerator mass spectrometry. Isotopic labelling not only allows for the accurate and efficient determination of absolute bioavailability, but can also provide information on first-pass effects and other pharmacokinetic parameters.
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Affiliation(s)
- Graham Lappin
- Xceleron Ltd, York BioCentre, Innovation Way, York, YO10 5NY, UK
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