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Serum Albumin: A Multifaced Enzyme. Int J Mol Sci 2021; 22:ijms221810086. [PMID: 34576249 PMCID: PMC8466385 DOI: 10.3390/ijms221810086] [Citation(s) in RCA: 74] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 09/14/2021] [Accepted: 09/15/2021] [Indexed: 02/06/2023] Open
Abstract
Human serum albumin (HSA) is the most abundant protein in plasma, contributing actively to oncotic pressure maintenance and fluid distribution between body compartments. HSA acts as the main carrier of fatty acids, recognizes metal ions, affects pharmacokinetics of many drugs, provides the metabolic modification of some ligands, renders potential toxins harmless, accounts for most of the anti-oxidant capacity of human plasma, and displays esterase, enolase, glucuronidase, and peroxidase (pseudo)-enzymatic activities. HSA-based catalysis is physiologically relevant, affecting the metabolism of endogenous and exogenous compounds including proteins, lipids, cholesterol, reactive oxygen species (ROS), and drugs. Catalytic properties of HSA are modulated by allosteric effectors, competitive inhibitors, chemical modifications, pathological conditions, and aging. HSA displays anti-oxidant properties and is critical for plasma detoxification from toxic agents and for pro-drugs activation. The enzymatic properties of HSA can be also exploited by chemical industries as a scaffold to produce libraries of catalysts with improved proficiency and stereoselectivity for water decontamination from poisonous agents and environmental contaminants, in the so called “green chemistry” field. Here, an overview of the intrinsic and metal dependent (pseudo-)enzymatic properties of HSA is reported to highlight the roles played by this multifaced protein.
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Toxicological potential of acyl glucuronides and its assessment. Drug Metab Pharmacokinet 2017; 32:2-11. [DOI: 10.1016/j.dmpk.2016.11.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 11/08/2016] [Accepted: 11/09/2016] [Indexed: 12/22/2022]
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Hammond TG, Meng X, Jenkins RE, Maggs JL, Castelazo AS, Regan SL, Bennett SNL, Earnshaw CJ, Aithal GP, Pande I, Kenna JG, Stachulski AV, Park BK, Williams DP. Mass spectrometric characterization of circulating covalent protein adducts derived from a drug acyl glucuronide metabolite: multiple albumin adductions in diclofenac patients. J Pharmacol Exp Ther 2014; 350:387-402. [PMID: 24902585 PMCID: PMC4109494 DOI: 10.1124/jpet.114.215079] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 05/29/2014] [Indexed: 12/21/2022] Open
Abstract
Covalent protein modifications by electrophilic acyl glucuronide (AG) metabolites are hypothetical causes of hypersensitivity reactions associated with certain carboxylate drugs. The complex rearrangements and reactivities of drug AG have been defined in great detail, and protein adducts of carboxylate drugs, such as diclofenac, have been found in liver and plasma of experimental animals and humans. However, in the absence of definitive molecular characterization, and specifically, identification of signature glycation conjugates retaining the glucuronyl and carboxyl residues, it cannot be assumed any of these adducts is derived uniquely or even fractionally from AG metabolites. We have therefore undertaken targeted mass spectrometric analyses of human serum albumin (HSA) isolated from diclofenac patients to characterize drug-: derived structures and, thereby, for the first time, have deconstructed conclusively the pathways of adduct formation from a drug AG and its isomeric rearrangement products in vivo. These analyses were informed by a thorough understanding of the reactions of HSA with diclofenac AG in vitro. HSA from six patients without drug-: related hypersensitivities had either a single drug-: derived adduct or one of five combinations of 2-8 adducts from among seven diclofenac N-acylations and three AG glycations on seven of the protein's 59 lysines. Only acylations were found in every patient. We present evidence that HSA modifications by diclofenac in vivo are complicated and variable, that at least a fraction of these modifications are derived from the drug's AG metabolite, and that albumin adduction is not inevitably a causation of hypersensitivity to carboxylate drugs or a coincidental association.
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Affiliation(s)
- Thomas G Hammond
- Medical Research Council Centre for Drug Safety Science, Institute of Translational Medicine, (T.G.H., X.M., R.E.J., J.L.M., A.S.C., S.L.R., C.J.E., B.K.P., D.P.W.) and Department of Chemistry (A.V.S.), University of Liverpool, Liverpool, United Kingdom; Nottingham Digestive Diseases Centre, NIHR Nottingham Digestive Diseases-Biomedical Research Unit, Nottingham University Hospitals NHS Trust and University of Nottingham (G.P.A.) and Department of Rheumatology, Nottingham University Hospitals NHS Trust (I.P.), Nottingham, United Kingdom; and AstraZeneca U.K. Ltd (S.N.L.B.) and Safety Assessment, AstraZeneca U.K. Ltd (J.G.K.), Alderley Park, Macclesfield, Cheshire, United Kingdom
| | - Xiaoli Meng
- Medical Research Council Centre for Drug Safety Science, Institute of Translational Medicine, (T.G.H., X.M., R.E.J., J.L.M., A.S.C., S.L.R., C.J.E., B.K.P., D.P.W.) and Department of Chemistry (A.V.S.), University of Liverpool, Liverpool, United Kingdom; Nottingham Digestive Diseases Centre, NIHR Nottingham Digestive Diseases-Biomedical Research Unit, Nottingham University Hospitals NHS Trust and University of Nottingham (G.P.A.) and Department of Rheumatology, Nottingham University Hospitals NHS Trust (I.P.), Nottingham, United Kingdom; and AstraZeneca U.K. Ltd (S.N.L.B.) and Safety Assessment, AstraZeneca U.K. Ltd (J.G.K.), Alderley Park, Macclesfield, Cheshire, United Kingdom
| | - Rosalind E Jenkins
- Medical Research Council Centre for Drug Safety Science, Institute of Translational Medicine, (T.G.H., X.M., R.E.J., J.L.M., A.S.C., S.L.R., C.J.E., B.K.P., D.P.W.) and Department of Chemistry (A.V.S.), University of Liverpool, Liverpool, United Kingdom; Nottingham Digestive Diseases Centre, NIHR Nottingham Digestive Diseases-Biomedical Research Unit, Nottingham University Hospitals NHS Trust and University of Nottingham (G.P.A.) and Department of Rheumatology, Nottingham University Hospitals NHS Trust (I.P.), Nottingham, United Kingdom; and AstraZeneca U.K. Ltd (S.N.L.B.) and Safety Assessment, AstraZeneca U.K. Ltd (J.G.K.), Alderley Park, Macclesfield, Cheshire, United Kingdom
| | - James L Maggs
- Medical Research Council Centre for Drug Safety Science, Institute of Translational Medicine, (T.G.H., X.M., R.E.J., J.L.M., A.S.C., S.L.R., C.J.E., B.K.P., D.P.W.) and Department of Chemistry (A.V.S.), University of Liverpool, Liverpool, United Kingdom; Nottingham Digestive Diseases Centre, NIHR Nottingham Digestive Diseases-Biomedical Research Unit, Nottingham University Hospitals NHS Trust and University of Nottingham (G.P.A.) and Department of Rheumatology, Nottingham University Hospitals NHS Trust (I.P.), Nottingham, United Kingdom; and AstraZeneca U.K. Ltd (S.N.L.B.) and Safety Assessment, AstraZeneca U.K. Ltd (J.G.K.), Alderley Park, Macclesfield, Cheshire, United Kingdom
| | - Anahi Santoyo Castelazo
- Medical Research Council Centre for Drug Safety Science, Institute of Translational Medicine, (T.G.H., X.M., R.E.J., J.L.M., A.S.C., S.L.R., C.J.E., B.K.P., D.P.W.) and Department of Chemistry (A.V.S.), University of Liverpool, Liverpool, United Kingdom; Nottingham Digestive Diseases Centre, NIHR Nottingham Digestive Diseases-Biomedical Research Unit, Nottingham University Hospitals NHS Trust and University of Nottingham (G.P.A.) and Department of Rheumatology, Nottingham University Hospitals NHS Trust (I.P.), Nottingham, United Kingdom; and AstraZeneca U.K. Ltd (S.N.L.B.) and Safety Assessment, AstraZeneca U.K. Ltd (J.G.K.), Alderley Park, Macclesfield, Cheshire, United Kingdom
| | - Sophie L Regan
- Medical Research Council Centre for Drug Safety Science, Institute of Translational Medicine, (T.G.H., X.M., R.E.J., J.L.M., A.S.C., S.L.R., C.J.E., B.K.P., D.P.W.) and Department of Chemistry (A.V.S.), University of Liverpool, Liverpool, United Kingdom; Nottingham Digestive Diseases Centre, NIHR Nottingham Digestive Diseases-Biomedical Research Unit, Nottingham University Hospitals NHS Trust and University of Nottingham (G.P.A.) and Department of Rheumatology, Nottingham University Hospitals NHS Trust (I.P.), Nottingham, United Kingdom; and AstraZeneca U.K. Ltd (S.N.L.B.) and Safety Assessment, AstraZeneca U.K. Ltd (J.G.K.), Alderley Park, Macclesfield, Cheshire, United Kingdom
| | - Stuart N L Bennett
- Medical Research Council Centre for Drug Safety Science, Institute of Translational Medicine, (T.G.H., X.M., R.E.J., J.L.M., A.S.C., S.L.R., C.J.E., B.K.P., D.P.W.) and Department of Chemistry (A.V.S.), University of Liverpool, Liverpool, United Kingdom; Nottingham Digestive Diseases Centre, NIHR Nottingham Digestive Diseases-Biomedical Research Unit, Nottingham University Hospitals NHS Trust and University of Nottingham (G.P.A.) and Department of Rheumatology, Nottingham University Hospitals NHS Trust (I.P.), Nottingham, United Kingdom; and AstraZeneca U.K. Ltd (S.N.L.B.) and Safety Assessment, AstraZeneca U.K. Ltd (J.G.K.), Alderley Park, Macclesfield, Cheshire, United Kingdom
| | - Caroline J Earnshaw
- Medical Research Council Centre for Drug Safety Science, Institute of Translational Medicine, (T.G.H., X.M., R.E.J., J.L.M., A.S.C., S.L.R., C.J.E., B.K.P., D.P.W.) and Department of Chemistry (A.V.S.), University of Liverpool, Liverpool, United Kingdom; Nottingham Digestive Diseases Centre, NIHR Nottingham Digestive Diseases-Biomedical Research Unit, Nottingham University Hospitals NHS Trust and University of Nottingham (G.P.A.) and Department of Rheumatology, Nottingham University Hospitals NHS Trust (I.P.), Nottingham, United Kingdom; and AstraZeneca U.K. Ltd (S.N.L.B.) and Safety Assessment, AstraZeneca U.K. Ltd (J.G.K.), Alderley Park, Macclesfield, Cheshire, United Kingdom
| | - Guruprasad P Aithal
- Medical Research Council Centre for Drug Safety Science, Institute of Translational Medicine, (T.G.H., X.M., R.E.J., J.L.M., A.S.C., S.L.R., C.J.E., B.K.P., D.P.W.) and Department of Chemistry (A.V.S.), University of Liverpool, Liverpool, United Kingdom; Nottingham Digestive Diseases Centre, NIHR Nottingham Digestive Diseases-Biomedical Research Unit, Nottingham University Hospitals NHS Trust and University of Nottingham (G.P.A.) and Department of Rheumatology, Nottingham University Hospitals NHS Trust (I.P.), Nottingham, United Kingdom; and AstraZeneca U.K. Ltd (S.N.L.B.) and Safety Assessment, AstraZeneca U.K. Ltd (J.G.K.), Alderley Park, Macclesfield, Cheshire, United Kingdom
| | - Ira Pande
- Medical Research Council Centre for Drug Safety Science, Institute of Translational Medicine, (T.G.H., X.M., R.E.J., J.L.M., A.S.C., S.L.R., C.J.E., B.K.P., D.P.W.) and Department of Chemistry (A.V.S.), University of Liverpool, Liverpool, United Kingdom; Nottingham Digestive Diseases Centre, NIHR Nottingham Digestive Diseases-Biomedical Research Unit, Nottingham University Hospitals NHS Trust and University of Nottingham (G.P.A.) and Department of Rheumatology, Nottingham University Hospitals NHS Trust (I.P.), Nottingham, United Kingdom; and AstraZeneca U.K. Ltd (S.N.L.B.) and Safety Assessment, AstraZeneca U.K. Ltd (J.G.K.), Alderley Park, Macclesfield, Cheshire, United Kingdom
| | - J Gerry Kenna
- Medical Research Council Centre for Drug Safety Science, Institute of Translational Medicine, (T.G.H., X.M., R.E.J., J.L.M., A.S.C., S.L.R., C.J.E., B.K.P., D.P.W.) and Department of Chemistry (A.V.S.), University of Liverpool, Liverpool, United Kingdom; Nottingham Digestive Diseases Centre, NIHR Nottingham Digestive Diseases-Biomedical Research Unit, Nottingham University Hospitals NHS Trust and University of Nottingham (G.P.A.) and Department of Rheumatology, Nottingham University Hospitals NHS Trust (I.P.), Nottingham, United Kingdom; and AstraZeneca U.K. Ltd (S.N.L.B.) and Safety Assessment, AstraZeneca U.K. Ltd (J.G.K.), Alderley Park, Macclesfield, Cheshire, United Kingdom
| | - Andrew V Stachulski
- Medical Research Council Centre for Drug Safety Science, Institute of Translational Medicine, (T.G.H., X.M., R.E.J., J.L.M., A.S.C., S.L.R., C.J.E., B.K.P., D.P.W.) and Department of Chemistry (A.V.S.), University of Liverpool, Liverpool, United Kingdom; Nottingham Digestive Diseases Centre, NIHR Nottingham Digestive Diseases-Biomedical Research Unit, Nottingham University Hospitals NHS Trust and University of Nottingham (G.P.A.) and Department of Rheumatology, Nottingham University Hospitals NHS Trust (I.P.), Nottingham, United Kingdom; and AstraZeneca U.K. Ltd (S.N.L.B.) and Safety Assessment, AstraZeneca U.K. Ltd (J.G.K.), Alderley Park, Macclesfield, Cheshire, United Kingdom
| | - B Kevin Park
- Medical Research Council Centre for Drug Safety Science, Institute of Translational Medicine, (T.G.H., X.M., R.E.J., J.L.M., A.S.C., S.L.R., C.J.E., B.K.P., D.P.W.) and Department of Chemistry (A.V.S.), University of Liverpool, Liverpool, United Kingdom; Nottingham Digestive Diseases Centre, NIHR Nottingham Digestive Diseases-Biomedical Research Unit, Nottingham University Hospitals NHS Trust and University of Nottingham (G.P.A.) and Department of Rheumatology, Nottingham University Hospitals NHS Trust (I.P.), Nottingham, United Kingdom; and AstraZeneca U.K. Ltd (S.N.L.B.) and Safety Assessment, AstraZeneca U.K. Ltd (J.G.K.), Alderley Park, Macclesfield, Cheshire, United Kingdom
| | - Dominic P Williams
- Medical Research Council Centre for Drug Safety Science, Institute of Translational Medicine, (T.G.H., X.M., R.E.J., J.L.M., A.S.C., S.L.R., C.J.E., B.K.P., D.P.W.) and Department of Chemistry (A.V.S.), University of Liverpool, Liverpool, United Kingdom; Nottingham Digestive Diseases Centre, NIHR Nottingham Digestive Diseases-Biomedical Research Unit, Nottingham University Hospitals NHS Trust and University of Nottingham (G.P.A.) and Department of Rheumatology, Nottingham University Hospitals NHS Trust (I.P.), Nottingham, United Kingdom; and AstraZeneca U.K. Ltd (S.N.L.B.) and Safety Assessment, AstraZeneca U.K. Ltd (J.G.K.), Alderley Park, Macclesfield, Cheshire, United Kingdom
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Stachulski AV, Baillie TA, Kevin Park B, Scott Obach R, Dalvie DK, Williams DP, Srivastava A, Regan SL, Antoine DJ, Goldring CEP, Chia AJL, Kitteringham NR, Randle LE, Callan H, Castrejon JL, Farrell J, Naisbitt DJ, Lennard MS. The Generation, Detection, and Effects of Reactive Drug Metabolites. Med Res Rev 2012; 33:985-1080. [DOI: 10.1002/med.21273] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Andrew V. Stachulski
- Department of Chemistry, Robert Robinson Laboratories; University of Liverpool; Liverpool; L69 7ZD; UK
| | - Thomas A. Baillie
- School of Pharmacy; University of Washington; Box 357631; Seattle; Washington; 98195-7631
| | - B. Kevin Park
- Department of Molecular and Clinical Pharmacology; MRC Centre for Drug Safety Science; Institute of Translational Medicine; University of Liverpool; Sherrington Buildings, Ashton Street; Liverpool L69 3GE; UK
| | - R. Scott Obach
- Pharmacokinetics, Dynamics and Metabolism; Pfizer Worldwide Research & Development; Groton; Connecticut 06340
| | - Deepak K. Dalvie
- Pharmacokinetics, Dynamics and Metabolism; Pfizer Worldwide Research & Development; La Jolla; California 94121
| | - Dominic P. Williams
- Department of Molecular and Clinical Pharmacology; MRC Centre for Drug Safety Science; Institute of Translational Medicine; University of Liverpool; Sherrington Buildings, Ashton Street; Liverpool L69 3GE; UK
| | - Abhishek Srivastava
- Department of Molecular and Clinical Pharmacology; MRC Centre for Drug Safety Science; Institute of Translational Medicine; University of Liverpool; Sherrington Buildings, Ashton Street; Liverpool L69 3GE; UK
| | - Sophie L. Regan
- Department of Molecular and Clinical Pharmacology; MRC Centre for Drug Safety Science; Institute of Translational Medicine; University of Liverpool; Sherrington Buildings, Ashton Street; Liverpool L69 3GE; UK
| | - Daniel J. Antoine
- Department of Molecular and Clinical Pharmacology; MRC Centre for Drug Safety Science; Institute of Translational Medicine; University of Liverpool; Sherrington Buildings, Ashton Street; Liverpool L69 3GE; UK
| | - Christopher E. P. Goldring
- Department of Molecular and Clinical Pharmacology; MRC Centre for Drug Safety Science; Institute of Translational Medicine; University of Liverpool; Sherrington Buildings, Ashton Street; Liverpool L69 3GE; UK
| | - Alvin J. L. Chia
- Department of Molecular and Clinical Pharmacology; MRC Centre for Drug Safety Science; Institute of Translational Medicine; University of Liverpool; Sherrington Buildings, Ashton Street; Liverpool L69 3GE; UK
| | - Neil R. Kitteringham
- Department of Molecular and Clinical Pharmacology; MRC Centre for Drug Safety Science; Institute of Translational Medicine; University of Liverpool; Sherrington Buildings, Ashton Street; Liverpool L69 3GE; UK
| | - Laura E. Randle
- School of Pharmacy and Biomolecular Sciences, Faculty of Science; Liverpool John Moores University; James Parsons Building, Byrom Street; Liverpool L3 3AF; UK
| | - Hayley Callan
- Department of Molecular and Clinical Pharmacology; MRC Centre for Drug Safety Science; Institute of Translational Medicine; University of Liverpool; Sherrington Buildings, Ashton Street; Liverpool L69 3GE; UK
| | - J. Luis Castrejon
- Department of Molecular and Clinical Pharmacology; MRC Centre for Drug Safety Science; Institute of Translational Medicine; University of Liverpool; Sherrington Buildings, Ashton Street; Liverpool L69 3GE; UK
| | - John Farrell
- Department of Molecular and Clinical Pharmacology; MRC Centre for Drug Safety Science; Institute of Translational Medicine; University of Liverpool; Sherrington Buildings, Ashton Street; Liverpool L69 3GE; UK
| | - Dean J. Naisbitt
- Department of Molecular and Clinical Pharmacology; MRC Centre for Drug Safety Science; Institute of Translational Medicine; University of Liverpool; Sherrington Buildings, Ashton Street; Liverpool L69 3GE; UK
| | - Martin S. Lennard
- Academic Unit of Medical Education; University of Sheffield; 85 Wilkinson Street; Sheffield S10 2GJ; UK
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Regan SL, Maggs JL, Hammond TG, Lambert C, Williams DP, Park BK. Acyl glucuronides: the good, the bad and the ugly. Biopharm Drug Dispos 2011; 31:367-95. [PMID: 20830700 DOI: 10.1002/bdd.720] [Citation(s) in RCA: 135] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Acyl glucuronidation is the major metabolic conjugation reaction of most carboxylic acid drugs in mammals. The physiological consequences of this biotransformation have been investigated incompletely but include effects on drug metabolism, protein binding, distribution and clearance that impact upon pharmacological and toxicological outcomes. In marked contrast, the exceptional but widely disparate chemical reactivity of acyl glucuronides has attracted far greater attention. Specifically, the complex transacylation and glycation reactions with proteins have provoked much inconclusive debate over the safety of drugs metabolised to acyl glucuronides. It has been hypothesised that these covalent modifications could initiate idiosyncratic adverse drug reactions. However, despite a large body of in vitro data on the reactions of acyl glucuronides with protein, evidence for adduct formation from acyl glucuronides in vivo is limited and potentially ambiguous. The causal connection of protein adduction to adverse drug reactions remains uncertain. This review has assessed the intrinsic reactivity, metabolic stability and pharmacokinetic properties of acyl glucuronides in the context of physiological, pharmacological and toxicological perspectives. Although numerous experiments have characterised the reactions of acyl glucuronides with proteins, these might be attenuated substantially in vivo by rapid clearance of the conjugates. Consequently, to delineate a relationship between acyl glucuronide formation and toxicological phenomena, detailed pharmacokinetic analysis of systemic exposure to the acyl glucuronide should be undertaken adjacent to determining protein adduct concentrations in vivo. Further investigation is required to ascertain whether acyl glucuronide clearance is sufficient to prevent covalent modification of endogenous proteins and consequentially a potential immunological response.
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Affiliation(s)
- Sophie L Regan
- MRC Centre for Drug Safety Science, Institute of Translational Medicine, The University of Liverpool, Liverpool L69 3GE, UK.
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Johnson CH, Karlsson E, Sarda S, Iddon L, Iqbal M, Meng X, Harding JR, Stachulski AV, Nicholson JK, Wilson ID, Lindon JC. Integrated HPLC-MS and (1)H-NMR spectroscopic studies on acyl migration reaction kinetics of model drug ester glucuronides. Xenobiotica 2010; 40:9-23. [PMID: 19919325 DOI: 10.3109/00498250903348720] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Acyl glucuronides (AGs) are common, chemically reactive metabolites of acidic xenobiotics. Concerns about the potential of this class of conjugate to cause toxicity in man require efficient methods for the determination of reactivity, and this is commonly done by measuring transacylation kinetics. High-performance liquid chromatography-mass spectrometry (HPLC-MS) and nuclear magnetic resonance (NMR) spectroscopy were applied to the kinetic analysis of AG isomerization and hydrolysis for the 1-beta-O-AGs of ibufenac, (R)- and (S)-ibuprofen, and an alpha,alpha-dimethylated ibuprofen analogue. Each AG was incubated in either aqueous buffer at pH 7.4 or human plasma at 37 degrees C. Aliquots of these samples, taken throughout the reaction time course, were analysed by HPLC-MS and (1)H-NMR spectroscopy and the results compared. For identification of the AGs incubated in pH 7.4 buffer and for analysis of kinetic rates, (1)H-NMR spectroscopy generally gave the most complete set of data, but for human plasma the use of (1)H-NMR spectroscopy was impractical and HPLC-MS was more suitable. HPLC-MS was more sensitive than (1)H-NMR spectroscopy, but the lack of suitable stable-isotope labelled internal standards, together with differences in response between glucuronides and aglycones, made quantification problematic. Using HPLC-MS a specific 1-beta-O-AG-related ion at m/z 193 (the glucuronate fragment) was noted enabling selective determination of these isomers. In buffer, transacylation reactions predominated, with relatively little hydrolysis to the free aglycone observed. In human plasma incubations the observed rates of reaction were much faster than for buffer, and hydrolysis to the free aglycone was the major route. These results illustrate the strengths and weaknesses of each analytical approach for this class of analyte.
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Affiliation(s)
- C H Johnson
- Biomolecular Medicine, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, Sir Alexander Fleming Building, South Kensington, London SW7 2AZ, UK
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Baba A, Yoshioka T. Structure−Activity Relationships for Degradation Reaction of 1-β-O-Acyl Glucuronides: Kinetic Description and Prediction of Intrinsic Electrophilic Reactivity under Physiological Conditions. Chem Res Toxicol 2008; 22:158-72. [DOI: 10.1021/tx800292m] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Akiko Baba
- Hokkaido Pharmaceutical University School of Pharmacy, 7-1 Katsuraoka-cho, Otaru, 047-0264, Hokkaido, Japan
| | - Tadao Yoshioka
- Hokkaido Pharmaceutical University School of Pharmacy, 7-1 Katsuraoka-cho, Otaru, 047-0264, Hokkaido, Japan
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Chapter 3 Glucuronidation-Dependent Toxicity and Bioactivation. ACTA ACUST UNITED AC 2008. [DOI: 10.1016/s1872-0854(07)02003-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Ma S, Subramanian R. Detecting and characterizing reactive metabolites by liquid chromatography/tandem mass spectrometry. JOURNAL OF MASS SPECTROMETRY : JMS 2006; 41:1121-39. [PMID: 16967439 DOI: 10.1002/jms.1098] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Metabolic activation of a drug leading to reactive metabolite(s) that can covalently modify proteins is considered an initial step that may lead to drug-induced organ toxicities. Characterization of reactive metabolites is critical to designing new drug candidates with an improved toxicological profile. High performance liquid chromatography (HPLC) coupled with mass spectrometry (MS) predominates over all analytical tools used for screening and characterization of reactive metabolites. In this review, a brief description of experimental approaches employed for assessing reactive metabolites is followed by a discussion on the reactivity of acyl glucuronides and acyl coenzyme A thioesters. Techniques for high-throughput screening and quantitation of reactive metabolite formation are also described, along with proteomic approaches used to identify protein targets and modification sites by reactive metabolites. Strategies for dealing with reactive metabolites are reviewed. In conclusion, we discuss the challenges and future needs in this field of research.
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Affiliation(s)
- Shuguang Ma
- Pharmacokinetics and Drug Metabolism, Amgen Inc., One Amgen Center Drive, Thousand Oaks, CA 91320, USA.
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Fennell TR, Krol WL, Sumner SCJ, Snyder RW. Pharmacokinetics of dibutylphthalate in pregnant rats. Toxicol Sci 2004; 82:407-18. [PMID: 15456918 DOI: 10.1093/toxsci/kfh294] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Dibutylphthalate (DBP) can cause adverse effects on the developing male reproductive tract when administered late in gestation to pregnant rats. The objectives of this study were to evaluate the metabolism of DBP in female rats, and the pharmacokinetics of DBP in pregnant rats on gestational day (g.d.) 20. The identities of DBP metabolites in urine and in maternal and fetal plasma were confirmed by LC-MS/MS, as monobutylphthalate (MBP) and its glucuronide, monohydroxybutylphthalate and its glucuronide, and butanoic acid phthalate and its glucuronide. An LC-MS/MS method was developed for the quantitation of MBP and its glucuronide. MBP and MBP glucuronide were quantitated in maternal and fetal plasma, and in amniotic fluid from pregnant rats administered a single dose of DBP (50, 100, or 250 mg/kg by gavage in corn oil) on g.d. 20. The pharmacokinetics of MBP and MBP glucuronide were determined. MBP was the major metabolite in maternal and fetal plasma. With increasing dose, there was a nonlinear increase in area under the curve (AUC) for MBP, with a ten-fold increase in maternal plasma, and an eight-fold increase in fetal plasma between 50 mg/kg and 250 mg/kg. In amniotic fluid, the major metabolite initially was MBP, but by 24 h after dosing, the major metabolite was MBP glucuronide. Isomers of the MBP glucuronide were detected in amniotic fluid, suggesting acyl group migration, known to occur with acyl glucuronides. This study indicated that MBP, thought to be the active metabolite of DBP, can cross the placenta in late gestation, and that the metabolism of MBP is saturable.
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Affiliation(s)
- Timothy R Fennell
- CIIT Centers for Health Research, 6 Davis Drive, Research Triangle Park, North Carolina 27709-2137, USA.
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Abstract
The metabolic conjugation of exogenous and endogenous carboxylic acid substrates with endogenous glucuronic acid, mediated by the uridine diphosphoglucuronosyl transferase (UGT) superfamily of enzymes, leads to the formation of acyl glucuronide metabolites. Since the late 1970s, acyl glucuronides have been increasingly identified as reactive electrophilic metabolites, capable of undergoing three reactions: intramolecular rearrangement, hydrolysis, and intermolecular reactions with proteins leading to covalent drug-protein adducts. This essential dogma has been accepted for over a decade. The key question proposed by researchers, and now the pharmaceutical industry, is: does or can the covalent modification of endogenous proteins, mediated by reactive acyl glucuronide metabolites, lead to adverse drug reactions, perhaps idiosyncratic in nature? This review evaluates the evidence for acyl glucuronide-derived perturbation of homeostasis, particularly that which might result from the covalent modification of endogenous proteins and other macromolecules. Because of the availability of acyl glucuronides for test tube/in vitro experiments, there is now a substantial literature documenting their rearrangement, hydrolysis and covalent modification of proteins in vitro. It is certain from in vitro experiments that serum albumin, dipeptidyl peptidase IV, tubulin and UGTs are covalently modified by acyl glucuronides. However, these in vitro experiments have been specifically designed to amplify any interference with a biological process in order to find biological effects. The in vivo situation is not at all clear. Certainly it must be concluded that all humans taking carboxylate drugs that form reactive acyl glucuronides will form covalent drug-protein adducts, and it must also be concluded that this in itself is normally benign. However, there is enough in vivo evidence implicating acyl glucuronides, which, when backed up by in vivo circumstantial and documented in vitro evidence, supports the view that reactive acyl glucuronides may initiate toxicity/immune responses. In summary, though acyl glucuronide-derived covalent modification of endogenous macromolecules is well-defined, the work ahead needs to provide detailed links between such modification and its possible biological consequences.
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Affiliation(s)
- Mark J Bailey
- Department of Medicine, Centre for Studies in Drug Disposition, The University of Queensland at Royal Brisbane Hospital, Queensland 4029, Australia
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12
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Ohkawa T, Norikura R, Yoshikawa T. Rapid LC-TOFMS method for identification of binding sites of covalent acylglucuronide-albumin complexes. J Pharm Biomed Anal 2003; 31:1167-76. [PMID: 12667932 DOI: 10.1016/s0731-7085(02)00733-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A method for rapid identification of binding sites of covalent adducts was developed using delta bilirubin as a model compound. Delta bilirubin, containing intact human serum albumin (HSA), was digested with trypsin and the peptide fragments were monitored at 436 nm, but no predominant peaks were detected indicating the instability of the digested peptides containing bilirubin-related compounds. Therefore, the high-performance liquid chromatography time-of-flight mass spectrometer (LC-TOFMS) data of digested fragments of delta bilirubin were compared with those of control digests of HSA, revealing a characteristic peptide in the digest mixture of delta bilirubin. This peptide was sequenced by high-performance liquid chromatography time-of-flight tandem mass spectrometry (LC-TOFMS/MS) and identified as LDELRDEGKASSAK (Leu182 to Lys195) with a modification of a 178 Da increase at Lys190. This indicated the Lys190 to be a predominant covalent binding site of BGs on HSA via the imine mechanism and the binding between the bilirubin moiety and the glucuronic acid moiety to be unstable to digestion with trypsin. The method of comparing LC-TOFMS data requires no specific detection such as fluorescence or radioactivity for every compound. This should accelerate the structure elucidation of covalent adducts and be helpful for studying the relationship between the structure of ligands and specific binding sites.
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Affiliation(s)
- T Ohkawa
- Drug Metabolism and Pharmacokinetics, Developmental Research Laboratories, Shionogi & Co Ltd, 3-1-1 Futaba-cho, Toyonaka, Osaka 561-0825, Japan.
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13
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Shipkova M, Armstrong VW, Oellerich M, Wieland E. Acyl glucuronide drug metabolites: toxicological and analytical implications. Ther Drug Monit 2003; 25:1-16. [PMID: 12548138 DOI: 10.1097/00007691-200302000-00001] [Citation(s) in RCA: 191] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Although glucuronidation is generally considered a detoxification route of drug metabolism, the chemical reactivity of acyl glucuronides has been linked with the toxic properties of drugs that contain carboxylic acid moieties. It is now well documented that such metabolites can reach appreciable concentrations in blood. Furthermore, they are labile, undergo hydrolysis and pH-dependent intramolecular acyl migration to isomeric conjugates of glucuronic acid, and may react irreversibly with plasma proteins, tissue proteins, and with nucleic acids. This stable binding causes chemical alterations that are thought to contribute to drug toxicity either through changes in the functional properties of the modified molecules or through antigen formation with subsequent hypersensitivity and other immune reactions. Whereas in vitro data on the toxicity of acyl glucuronides have steadily accumulated, direct evidence for their toxicity in vivo is scarce. Acyl glucuronides display limited stability, which is dependent on pH, temperature, nature of the aglycon, and so on. Therefore, careful sample collection, handling, and storage procedures are critical to ensure generation of reliable pharmacologic and toxicologic data during clinical studies. Acyl glucuronides can be directly quantified in biologic specimens using chromatographic procedures. Their adducts with plasma or cell proteins can be determined after electrophoretic separation, followed by blotting. ELISA techniques have been used to assess the presence of antibodies against acyl glucuronide-protein adducts. This review summarizes the most recent evidence concerning biologic and toxicologic effects of acyl glucuronide metabolites of various drugs and discusses their relevance for drug monitoring. A critical evaluation of the available methodology is included.
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Affiliation(s)
- Maria Shipkova
- Department of Clinical Chemistry, Georg-August-University, Göttingen, Germany.
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14
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Rainsford KD, Omar H, Ashraf A, Hewson AT, Bunning RAD, Rishiraj R, Shepherd P, Seabrook RW. Recent pharmacodynamic and pharmacokinetic findings on oxaprozin. Inflammopharmacology 2002. [DOI: 10.1163/156856002321168204] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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15
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Georges H, Presle N, Buronfosse T, Fournel-Gigleux S, Netter P, Magdalou J, Lapicque F. In vitro stereoselective degradation of carprofen glucuronide by human serum albumin. Characterization of sites and reactive amino acids. Chirality 2000; 12:53-62. [PMID: 10637410 DOI: 10.1002/(sici)1520-636x(2000)12:2<53::aid-chir1>3.0.co;2-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Acyl glucuronides formed from carboxylic acids can undergo hydrolysis, acyl migration, and covalent binding to proteins. In buffers at physiological pH, the degradation of acylglucuronide of a chiral NSAID, carprofen, consisted mainly of acyl migration. Acidic pH reduced hydrolysis and acyl migration, thus stabilizing the carprofen acyl glucuronides. Addition of human serum albumin (HSA) led to an increased hydrolysis of the conjugates of both enantiomers. This protein protected R-carprofen glucuronide from migration and therefore improved its overall stability. Hydrolysis was stereoselective in favor of the S conjugate. The protein domains and the amino acid residues likely to be responsible for the hydrolytic activity of HSA were deduced from the results of various investigations: competition with probes specific of binding sites, effects of pH and of chemical modifications of albumin. Dansylsarcosine (DS), a specific ligand of site II of HSA, impaired the hydrolysis, whereas dansylamide (DNSA) and digoxin, which are specific ligands of sites I and III, respectively, had no effect. The extent of hydrolysis by HSA strongly increased with pH, indicating the participation of basic amino acids in this process. The results obtained with chemically modified HSA suggest the major involvement of Tyr and Lys residues in the hydrolysis of glucuronide of S-carprofen, and of other Lys residues for that of its diastereoisomer.
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Affiliation(s)
- H Georges
- UMR 7561 CNRS-UHP Nancy 1, Physiopathologie et Pharmacologie Articulaires, Faculté de Médecine, France
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16
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Mizuma T, Benet LZ, Lin ET. Interaction of human serum albumin with furosemide glucuronide: a role of albumin in isomerization, hydrolysis, reversible binding and irreversible binding of a 1-O-acyl glucuronide metabolite. Biopharm Drug Dispos 1999; 20:131-6. [PMID: 10211865 DOI: 10.1002/(sici)1099-081x(199904)20:3<131::aid-bdd166>3.0.co;2-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Furosemide 1-O-acyl glucuronide (Fgnd) was reversibly bound to a single class of binding sites on human serum albumin (HSA), and the binding of Fgnd decreased with increasing F concentrations, suggesting that Fgnd binds to the same warfarin binding sites on HSA as F binds. The rate of Fgnd degradation (hydrolysis and acyl migration) decreased in the presence of HSA. Although the formation of acyl migration isomers of Fgnd was slower in the presence of HSA than in its absence, hydrolysis of Fgnd to F was faster in the presence of HSA. Rapid minor irreversible binding of Fgnd to HSA within 30 min was followed by slow major irreversible binding. Slow irreversible binding of Fgnd to HSA was decreased by F, though not significantly. This suggests that major irreversible binding may proceed via reversible binding. It has been reported that acyl migration is a prerequisite for irreversible binding. Therefore, these results indicate that HSA decreases irreversible binding of Fgnd to protein by suppressing acyl migration. Furthermore, these results suggest that HSA may prevent irreversible binding of Fgnd to other proteins in the body by decreasing the concentration of reactive Fgnd in the unbound form. HSA eliminates reactive Fgnd by hydrolysis to F. Therefore, it is concluded that HSA works as a scavenger to decrease reactive compounds by reversible binding or eliminates reactive compounds by irreversible binding.
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Affiliation(s)
- T Mizuma
- Department of Biopharmaceutical Sciences, University of California, San Francisco 94143, USA.
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17
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Iwaki M, Ogiso T, Inagawa S, Kakehi K. In vitro regioselective stability of beta-1-O- and 2-O-acyl glucuronides of naproxen and their covalent binding to human serum albumin. J Pharm Sci 1999; 88:52-7. [PMID: 9874702 DOI: 10.1021/js9802704] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
beta-1-O- (NAG) and 2-O-glucuronides (2-isomer) of (S)-naproxen (NA) were prepared to determine which positional isomer(s) of the acyl glucuronide of NA is responsible for forming covalent adducts with human serum albumin (HSA). Their comparative stability and covalent binding adduct formation with HSA were investigated at pH 7.4 and at 37 degreesC. NA and its acyl glucuronides were simultaneously determined by HPLC. Three positional isomers were formed successively after incubation of NAG in the buffer only. However, when NAG was incubated with HSA (30 mg/mL), isomers other than the 2-isomer were formed in little or negligible quantities. In HSA solution, NAG (kd = 2.08 +/- 0.08 h-1) was four times less stable than 2-isomer (kd = 0.51 +/- 0.02 h-1). NAG was degraded by hydrolysis (khyd = 1.01 +/- 0.10 h-1) and isomerization (kiso = 1.07 +/- 0.07 h-1) to the same extent; however, hydrolysis was predominant for the 2-isomer (kd = 0.51 +/- 0.02 h-1). The incubation of both NAG and 2-isomer with HSA led to the formation of a covalent adduct; however, the adduct formation from the 2-isomer proceeded more slowly than that from NAG. The present results suggest that the covalent binding of NA to HSA via its acyl glucuronides proceeds through both transacylation (direct nucleophilic displacement) and glycation mechanisms; NAG rapidly forms an adduct that may be unstable, and the protein adduct from the 2-O-acyl glucuronide is as important for the covalent binding as those from the 1-O-acyl glucuronides.
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Affiliation(s)
- M Iwaki
- Faculty of Pharmaceutical Sciences, Kinki University, 3-4-1 Kowakae, Higashi-Osaka, Osaka 577-8502,
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18
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Liu JH, Marquez CD, Weintraub ST, Smith PC. Reaction of acyl glucuronides with insulin in vitro: identification of an imine mechanism by electrospray ionization mass spectrometry. Pharm Res 1998; 15:343-6. [PMID: 9523325 DOI: 10.1023/a:1011995408539] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- J H Liu
- School of Pharmacy, University of North Carolina at Chapel Hill 27599, USA
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19
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Bischer A, Zia-Amirhosseini P, Iwaki M, McDonagh AF, Benet LZ. Stereoselective binding properties of naproxen glucuronide diastereomers to proteins. JOURNAL OF PHARMACOKINETICS AND BIOPHARMACEUTICS 1995; 23:379-95. [PMID: 8882746 DOI: 10.1007/bf02353639] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The stability of naproxen glucuronide (NAP-G) diastereomers was investigated in buffer, 0.3% and 3% human serum albumin (HSA) solutions, and human plasma. R-NAP-G was found to be less stable in phosphate buffer than its S-diastereomer, whereas incubation media containing protein in general increased the degradation rate of NAP-G but also caused a change of the stereoselective stability where the R-NAP-G was more stable than S-NAP-G. Reversible binding of NAP-Gs to HSA (0.3%) was investigated and compared with the corresponding properties of naproxen (NAP) enantiomers. NAP-G diastereomers exhibited a considerable and stereoselective affinity to HSA, although less than that observed for the NAP enantiomers. In vitro irreversible binding of NAP-Gs to HSA, human and rat plasma proteins was also investigated. Irreversible binding was higher for R-NAP-G (50 microM) than for S-NAP-G (50 microM) in all incubation media. This stereoselective difference was observed with HSA containing medium as well as in rat and human plasma. Incubation with unconjugated NAP did not lead to irreversible binding. Preincubation of HSA with acetylsalicylic acid (approximately 11 mM) and glucuronic acid (50 mM) decreased the extent of irreversible binding suggesting involvement of lysine residues for covalent binding. Preincubation with S-NAP also decreased the irreversible binding yield.
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Affiliation(s)
- A Bischer
- Department of Pharmacy, University of California, San Francisco 94143-0446, USA
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20
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Boelsterli UA, Zimmerman HJ, Kretz-Rommel A. Idiosyncratic liver toxicity of nonsteroidal antiinflammatory drugs: molecular mechanisms and pathology. Crit Rev Toxicol 1995; 25:207-35. [PMID: 7576152 DOI: 10.3109/10408449509089888] [Citation(s) in RCA: 135] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
This review explores the clinical hepatic pathology associated with the use of nonsteroidal antiinflammatory drugs (NSAIDs), possible cellular and molecular mechanisms of injury, and future challenges. NSAIDs comprise a group of widely used compounds that have been associated with rare adverse reactions in the liver, including fulminant hepatitis and cholestasis. These reactions are idiosyncratic, mostly independent of the dose administered, and host-dependent. The mechanisms responsible for the initiation and perpetuation of NSAID-induced hepatotoxicity remain poorly understood and have been largely inferred from clinical manifestation. A mounting body of evidence, however, indicates that many acidic NSAIDs are metabolized to reactive acyl glucuronides that can form covalent adducts with plasma proteins and hepatocellular proteins. In hepatocytes cocultured with lymphocytes, these NSAID-altered proteins can become antigenic. Thus, long-lived, drug-altered proteins may act as immunogens and produce cytotoxic T-cell-mediated or antibody-dependent, cell-mediated toxicity in susceptible patients. Alternatively, individual abnormalities in metabolism or disposition of some NSAIDs may lead to the formation or accumulation of toxic metabolites. Additional work with transgenic animal models is needed to permit better understanding of the general and specific risk factors involved in the pathogenesis of the idiosyncratic liver injuries related to NSAIDs and other drugs.
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Affiliation(s)
- U A Boelsterli
- Institute of Toxicology, Swiss Federal Institute of Technology, Schwerzenbach
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21
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Affiliation(s)
- P J Hayball
- Pharmacy Department, Repatriation General Hospital, Adelaide, South Australia
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Ojingwa JC, Spahn-Langguth H, Benet LZ. Reversible binding of tolmetin, zomepirac, and their glucuronide conjugates to human serum albumin and plasma. JOURNAL OF PHARMACOKINETICS AND BIOPHARMACEUTICS 1994; 22:19-40. [PMID: 8027947 DOI: 10.1007/bf02353408] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Acyl glucuronides of drugs and bilirubin have been shown in the past decade to be reactive metabolites undergoing acyl migration and irreversible binding. The latter reaction has been hypothesized to be facilitated by or to proceed through the formation of a reversible complex. Furthermore, it has been suggested that the decreased binding seen in patients with compromised excretory function may be due to competition by elevated plasma concentrations of the glucuronides. In these reversible binding studies, we characterized the extent and the "site" of binding of tolmetin, zomepirac, their glucuronides and isomeric conjugates. We also examined the displacement between the parent drugs and their glucuronide conjugates using a rapid ultrafiltration method. Tolmetin exhibited three classes of binding sites with a primary association constant of 1.7 x 10(6) M-1 (Kd1 = 0.60 microM). The primary association constant of zomepirac (1.16 x 10(6) M-1, Kd1 = 0.86 microM) is similar to that of tolmetin. The beta 1 and alpha/beta 3 glucuronides of both compounds bind to a lesser extent than their parent aglycones. The isomeric glucuronide conjugates of both compounds showed much stronger binding than the beta/1 conjugates. Of the four glucuronides investigated, tolmetin glucuronide-alpha/beta 3 isomer was bound by fatty acid free human serum albumin with the highest affinity (4.6 x 10(5) M-1, Kd = 2.22 microM). Protein binding of the parent drugs and conjugates were decreased significantly at pH 5.0. In displacement studies, except for salicylate and acetylsalicylate, drugs known to bind to Sites I and II as well as the digitoxin and tamoxifen binding sites had little inhibitory effect on the binding of tolmetin, zomepirac, and their glucuronide conjugates.
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Affiliation(s)
- J C Ojingwa
- Department of Pharmacy, University of California, San Francisco 94143-0446
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23
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Zia-Amirhosseini P, Spahn-Langguth H, Benet LZ. Bioactivation by glucuronide-conjugate formation. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 1994; 27:385-97. [PMID: 8068561 DOI: 10.1016/s1054-3589(08)61040-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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24
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Affiliation(s)
- H Cheng
- Department of Drug Metabolism, Merck Research Laboratories, West Point, PA 19486
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25
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Ding A, Ojingwa JC, McDonagh AF, Burlingame AL, Benet LZ. Evidence for covalent binding of acyl glucuronides to serum albumin via an imine mechanism as revealed by tandem mass spectrometry. Proc Natl Acad Sci U S A 1993; 90:3797-801. [PMID: 8483897 PMCID: PMC46392 DOI: 10.1073/pnas.90.9.3797] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Acyl glucuronide metabolites of bilirubin and many drugs can react with serum albumin in vivo to form covalent adducts. Such adducts may be responsible for some toxic effects of carboxylic nonsteroidal antiinflammatory agents. The mechanism of formation of the adducts and their chemical structures are unknown. In this paper we describe the use of tandem mass spectrometry to locate binding sites and elucidate the binding mechanism involved in the formation of covalent adducts from tolmetin glucuronide and albumin in vitro. Human serum albumin and excess tolmetin glucuronide were coincubated in the presence of sodium cyanoborohydride to trap imine intermediates. The total protein product was reduced, carboxymethylated, and digested with trypsin. Six tolmetin-containing peptides (indicated by absorbance at 313 nm) were isolated by high-pressure liquid chromatography and analyzed by liquid secondary-ion mass spectrometry and collision-induced dissociation, using a four-sector tandem mass spectrometer. All six peptides contained tolmetin linked covalently via a glucuronic acid to protein lysine groups. Major attachment sites on the protein were Lys-195, -199, and -525; minor sites were identified as Lys-137, -351, and -541. Our results show unambiguously that the glucuronic acid moiety of acyl glucuronides can be retained within the structure when these reactive metabolites bind covalently to proteins, and they suggest that acyl migration followed by Schiff base (imine) formation is a credible mechanism for the generation of covalent adducts in vivo.
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Affiliation(s)
- A Ding
- Department of Pharmacy, University of California, San Francisco 94143-0446
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26
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Spahn-Langguth H, Benet LZ. Acyl glucuronides revisited: is the glucuronidation process a toxification as well as a detoxification mechanism? Drug Metab Rev 1992; 24:5-47. [PMID: 1555494 DOI: 10.3109/03602539208996289] [Citation(s) in RCA: 301] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- H Spahn-Langguth
- Department of Pharmacy, University of California, San Francisco 94143-0446
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Newcombe DS. Chiral stereoisomeric molecules in the treatment of arthritis. Semin Arthritis Rheum 1991; 21:88-102. [PMID: 1749943 DOI: 10.1016/0049-0172(91)90042-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Pharmacokinetic and pharmacodynamic properties of drugs and their ultimate therapeutic effects are often significantly influenced by interactions between the geometry of host receptors, host enzymes, and the three-dimensional structure of drugs. Drug molecules that are mirror images of each other are chiral stereoisomers, and such chiral isomer compounds are commonly used as therapeutic agents by rheumatologists either as racemates (mixtures of chiral isomers) or as pure stereoisomers. Understanding and using such stereoisomeric drugs may lead to lower risks of drug toxicity, better therapeutic indices, and newer approaches for the treatment of articular disorders. A review of the properties of these special isomers is presented, and their therapeutic advantages are discussed.
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Affiliation(s)
- D S Newcombe
- Department of Environmental Health Sciences and Medicine, Johns Hopkins Medical Institutions, Baltimore, MD 21205
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28
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Sallustio BC, Knights KM, Roberts BJ, Zacest R. In vivo covalent binding of clofibric acid to human plasma proteins and rat liver proteins. Biochem Pharmacol 1991; 42:1421-5. [PMID: 1930265 DOI: 10.1016/0006-2952(91)90454-d] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Recent studies have shown that acyl-glucuronide conjugates are chemically reactive electrophilic metabolites that can undergo transacylation reactions resulting in intra-molecular rearrangement, hydrolysis and covalent binding of aglycone to albumin both in vitro and in vivo. The hypolipidaemic agent clofibrate is eliminated almost entirely as clofibric acid glucuronide in humans and rats. The formation of clofibric acid-protein adducts was investigated in 14 patients receiving 0.5-2.0 g/day of clofibrate for hypercholesterolaemia, and in liver homogenates from 20 rats administered 280 mg/kg/day of clofibric acid for up to 21 days. Total clofibric acid concentrations in the patients ranged from 0 to 114 mg/L. Covalently bound clofibric acid-protein adducts were detected in all patients, even in one subject in whom there was no measurable plasma clofibric acid. Concentrations ranged from 2.2 to 53.4 ng/mg protein and, in eight patients receiving 1.0 g/day of clofibrate, were correlated (P less than 0.05) with renal function as assessed by creatinine clearance. Clofibric acid-protein adducts were also present in rat liver homogenates, and increased with increasing duration of treatment (P less than 0.0001), from a mean (SE) of 10.1 (0.7) to 32.3 (1.6) ng/mg protein. The covalent binding of drugs to tissue macromolecules has traditionally been associated with toxicity. Further research is required to elucidate the role of acyl-glucuronide conjugates in the formation of drug-protein adducts and their biological consequences.
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Affiliation(s)
- B C Sallustio
- Department of Clinical Pharmacology, Queen Elizabeth Hospital, Woodville South, Australia
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29
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Watt JA, King AR, Dickinson RG. Contrasting systemic stabilities of the acyl and phenolic glucuronides of diflunisal in the rat. Xenobiotica 1991; 21:403-15. [PMID: 1862662 DOI: 10.3109/00498259109039480] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
1. Diflunisal (DF) is metabolized in humans and rats primarily to its acyl glucuronide, phenolic glucuronide and sulphate conjugates. 2. After i.v. administration of DF acyl glucuronide to pentobarbitone-anaesthetized rats, DF and its phenolic glucuronide and sulphate conjugates appeared rapidly in plasma, indicating ready systemic hydrolysis of the acyl glucuronide and subsequent biotransformation of liberated DF. 3. Approximately 72% of the acyl glucuronide dose was recovered in bile and urine over 6 h: 52% as acyl glucuronide, 6% as phenolic glucuronide, 5% as sulphate, and 8% as isomers of the acyl glucuronide arising from intramolecular acyl migration. 4. Blockage of excretion routes by ligation of the ureters, bile duct, and both ureters and bile duct, decreased plasma clearance of the acyl glucuronide from 7.8 ml/min per kg to 6.0, 3.2 and 2.2 ml/min per kg respectively, and increased the apparent terminal plasma half-life of DF from 2.1 h to 2.6, 3.4 and 6.3 h, respectively. 5. By contrast, DF phenolic glucuronide was quite stable after i.v. administration at the same dose. 6. This study shows that systemic cycling between DF and its acyl glucuronide exists in the rat in vivo, with portions of each cycle of unstable acyl glucuronide through DF yielding stable phenolic glucuronide and (presumptively stable) sulphate conjugate.
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Affiliation(s)
- J A Watt
- Department of Medicine, University of Queensland, Royal Brisbane Hospital, Australia
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30
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Munafo A, McDonagh AF, Smith PC, Benet LZ. Irreversible binding of tolmetin glucuronic acid esters to albumin in vitro. Pharm Res 1990; 7:21-7. [PMID: 2300531 DOI: 10.1023/a:1015823206607] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Tolmetin glucuronide (TG), extracted and purified from human urine, was incubated with albumin in vitro. The degradation profile and irreversible binding to protein were investigated and kinetic parameters calculated. Standard conditions were as follows: TG, 30 micrograms/ml; human serum albumin (HSA), 3%; pH 7.45; 37 degrees C. Lower pH enhanced TG stability and reduced both the extent and the rate of irreversible binding. HSA also increased TG stability, compared to protein-free buffer, but the opposite was observed with bovine serum albumin (BSA). With BSA, irreversible binding was much less, but the rate of adduct formation was the same as with HSA. Essentially fatty acid free HSA behaved similarly to HSA. Preincubation of HSA with warfarin, or diazepam, or an excess of tolmetin, did not influence irreversible binding significantly. In buffer, acyl migration led predominantly to one isomer. This isomer bound irreversibly to HSA, although more slowly and to a lesser extent than the beta 1-isomer. Incubation of TG with poly-L-lysine also resulted in irreversible binding but to a lesser extent than with HSA. Our results suggest that there is more than one binding mechanism, with the preferential pathway a function of the isomers present and the experimental conditions.
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Affiliation(s)
- A Munafo
- Department of Pharmacy, School of Pharmacy, University of California, San Francisco 94143-0446
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