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Venkatapura Chandrashekar D, Mehvar R. UPLC-MS/MS analysis of CYP1A-mediated ethoxyresorufin-O-deethylation activity in the rat kidney microsomes. J Chromatogr B Analyt Technol Biomed Life Sci 2020; 1153:122272. [PMID: 32738524 DOI: 10.1016/j.jchromb.2020.122272] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 07/03/2020] [Accepted: 07/12/2020] [Indexed: 10/23/2022]
Abstract
Ethoxyresorufin (ER)-O-deethylation (EROD) activity has been widely used to assess cytochrome P450 1A (CYP1A) activity. The kinetics of CYP1A activity have been well characterized in the liver microsomes. However, studies in kidney microsomes are limited due to the much lower EROD activity in this organ. Here, we developed and validated a sensitive UPLC-MS/MS assay for the characterization of the EROD activity in the rat kidney microsomes. In a 50 µL reaction mixture, rat kidney microsomes (0.25 mg/mL) were incubated with ER (0.1-5 µM) and NADPH (1 mM) for 10 min. Acidic solvents, such as trichloroacetic acid or formic acid, used for quenching of the metabolic reactions and precipitation of the proteins, unexpectedly caused a spontaneous formation of resorufin (RES) from ER. Therefore, the metabolic reactions were terminated by adding acetonitrile, containing a deuterated internal standard (IS). Chromatographic separation was achieved on a C18 UPLC column, and the MS/MS ion transitions were 213.9/185.9 for RES and 220.0/192.0 for IS. The assay was validated in the linear range of 0.5 nM to 75 nM of RES and had a lower limit of quantitation of 0.5 nM. The overall recoveries of RES (90%-99%) and IS (85%-103%) were relatively high, with minimal matrix effect. The assay was successfully applied to the estimation of the Michaelis-Menten (MM) kinetics of EROD activity in the rat kidney microsomes (n = 3), which showed a maximum velocity of 2.68 ± 0.17 pmol/min/mg and a MM constant of 1.72 ± 0.24 µM (mean ± SD). It is concluded that our sensitive and specific analytical method, coupled with the optimized microsomal incubation conditions, provides a robust platform for further investigations of the effects of xenobiotics, environmental factors, or pathophysiologic conditions on the kinetics of EROD activity in the kidney microsomes.
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Affiliation(s)
| | - Reza Mehvar
- Department of Biomedical and Pharmaceutical Sciences, School of Pharmacy, Chapman University, Irvine, USA.
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Chen ZH, Zhang SX, Long N, Lin LS, Chen T, Zhang FP, Lv XQ, Ye PZ, Li N, Zhang KZ. An improved substrate cocktail for assessing direct inhibition and time-dependent inhibition of multiple cytochrome P450s. Acta Pharmacol Sin 2016; 37:708-18. [PMID: 27063220 PMCID: PMC4857547 DOI: 10.1038/aps.2016.10] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 01/05/2016] [Indexed: 11/08/2022] Open
Abstract
AIM The substrate cocktail is frequently used to evaluate cytochrome P450 (CYP) enzyme-mediated drug interactions and potential interactions among the probe substrates. Here, we re-optimized the substrate cocktail method to increase the reliability and accuracy of screening for candidate compounds and expanded the method from a direct CYP inhibition assay to a time-dependent inhibition (TDI) assay. METHODS In the reaction mixtures containing human liver microsome (0.1 mg/mL), both the concentrations of a substrate cocktail (phenacetin for 1A2, coumarin for 2A6, bupropion for 2B6, diclofenac for 2C9, dextromethorphan for 2D6, and testosterone for 3A4) and the incubation time were optimized. Metabolites of the substrate probes were simultaneously analyzed by multiple-reaction monitoring (MRM) using a routine LC/MS/MS. Direct CYP inhibition was validated using 7 inhibitors (α-naphthoflavone, tranylcypromine, ticlopidine, fluconazole, quinidine, ketoconazole and 1-ABT). The time-dependent inhibition was partially validated with 5 inhibitors (ketoconazole, verapamil, quinidine, paroxetine and 1-ABT). RESULTS The inhibition curve profiles and IC50 values of 7 CYP inhibitors were approximate when a single substrate and the substrate cocktail were tested, and were consistent with the previously reported values. Similar results were obtained in the IC50 shifts of 5 inhibitors when a single substrate and the substrate cocktail were tested in the TDI assay. CONCLUSION The 6-in-1 substrate cocktail (for 1A2, 2A6, 2B6, 2C9, 2D6 and 3A) is reliable for assessing CYP inhibition and time-dependent inhibition of drug candidates.
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Affiliation(s)
- Zhong-hua Chen
- Department of Pharmacology, West China School of Pharmacy, Sichuan University, Chengdu 610041, China
- Key Laboratory of Drug Targeting, Ministry of Education, West China School of Pharmacy, Sichuan University, Chengdu 610041, China
| | - Su-xing Zhang
- CarysBio Holdings Limited, Chancheng, Foshan 528000, China
| | - Na Long
- CarysBio Holdings Limited, Chancheng, Foshan 528000, China
| | - Li-shan Lin
- CarysBio Holdings Limited, Chancheng, Foshan 528000, China
| | - Tao Chen
- CarysBio Holdings Limited, Chancheng, Foshan 528000, China
| | - Fei-peng Zhang
- CarysBio Holdings Limited, Chancheng, Foshan 528000, China
| | - Xue-qin Lv
- CarysBio Holdings Limited, Chancheng, Foshan 528000, China
| | - Pei-zhen Ye
- CarysBio Holdings Limited, Chancheng, Foshan 528000, China
| | - Ning Li
- School of Biological Science and Technology, University of Ji-nan, Ji-nan 250022, China
| | - Ke-zhi Zhang
- CarysBio Holdings Limited, Chancheng, Foshan 528000, China
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Kramlinger VM, Alvarado Rojas M, Kanamori T, Guengerich FP. Cytochrome P450 3A Enzymes Catalyze the O6-Demethylation of Thebaine, a Key Step in Endogenous Mammalian Morphine Biosynthesis. J Biol Chem 2015; 290:20200-10. [PMID: 26157146 DOI: 10.1074/jbc.m115.665331] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Indexed: 01/08/2023] Open
Abstract
Morphine, first characterized in opium from the poppy Papaver somniferum, is one of the strongest known analgesics. Endogenous morphine has been identified in several mammalian cells and tissues. The synthetic pathway of morphine in the opium poppy has been elucidated. The presence of common intermediates in plants and mammals suggests that biosynthesis occurs through similar pathways (beginning with the amino acid L-tyrosine), and the pathway has been completely delineated in plants. Some of the enzymes in the mammalian pathway have been identified and characterized. Two of the latter steps in the morphine biosynthesis pathway are demethylation of thebaine at the O(3)- and the O(6)-positions, the latter of which has been difficult to demonstrate. The plant enzymes responsible for both the O(3)-demethylation and the O(6)-demethylation are members of the Fe(II)/α-ketoglutarate-dependent dioxygenase family. Previous studies showed that human cytochrome P450 (P450) 2D6 can catalyze thebaine O(3)-demethylation. We report that demethylation of thebaine at the O(6)-position is selectively catalyzed by human P450s 3A4 and 3A5, with the latter being more efficient, and rat P450 3A2. Our results do not support O(6)-demethylation of thebaine by an Fe(II)/α-ketoglutarate-dependent dioxygenase. In rat brain microsomes, O(6)-demethylation was inhibited by ketoconazole, but not sulfaphenazole, suggesting that P450 3A enzymes are responsible for this activity in the brain. An alternate pathway to morphine, oripavine O(6)-demethylation, was not detected. The major enzymatic steps in mammalian morphine synthesis have now been identified.
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Affiliation(s)
- Valerie M Kramlinger
- From the Department of Biochemistry, School of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146
| | - Mónica Alvarado Rojas
- From the Department of Biochemistry, School of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146
| | - Tatsuyuki Kanamori
- From the Department of Biochemistry, School of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146
| | - F Peter Guengerich
- From the Department of Biochemistry, School of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146
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Lee JT, Pao LH, Hsiong CH, Huang PW, Shih TY, Yoa-Pu Hu O. Validated liquid chromatography–tandem mass spectrometry method for determination of totally nine probe metabolites of cytochrome P450 enzymes and UDP-glucuronosyltransferases. Talanta 2013; 106:220-8. [DOI: 10.1016/j.talanta.2012.12.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Revised: 12/10/2012] [Accepted: 12/11/2012] [Indexed: 12/11/2022]
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Zientek M, Youdim K. Simultaneous determination of multiple CYP inhibition constants using a cocktail-probe approach. Methods Mol Biol 2013; 987:11-23. [PMID: 23475664 DOI: 10.1007/978-1-62703-321-3_2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
To identify cytochrome P450 (CYP) drug-drug interaction (DDI) potential of a new chemical entity, the use of a specific clinically relevant probe substrate in the presence of a test compound is common place. In early discovery of new chemical entities, a balance of rigor, the ability to predict clinical DDI, and throughput is desired in an in vitro assay. This chapter describes a high-throughput CYP-mediated DDI assay method that balances these characteristics. The method utilizes a cassette approach using a cocktail of five selective probe substrates for the major clinically relevant CYPs involved in drug interactions. CYP1A2, 2C9, 2C19, 2D6, and 3A activities are assessed with liquid chromatography/tandem mass spectrometry (LC-MS/MS) quantification of metabolite formation. The method also outlines specific inhibitors to evaluate dynamic range and as a positive control. The benefits and needs for caution of this method are noted and discussed.
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Zhang L, Wei MJ, Zhao CY, Qi HM. Determination of the inhibitory potential of 6 fluoroquinolones on CYP1A2 and CYP2C9 in human liver microsomes. Acta Pharmacol Sin 2008; 29:1507-14. [PMID: 19026171 DOI: 10.1111/j.1745-7254.2008.00908.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
AIM To determine the inhibitory potential of 2 new fluoroquinolones, caderofloxacin and antofloxacin, together with 4 marketed fluoroquinolones, moxifloxacin, gatifloxacin, levofloxacin, and ciprofloxacin, on the activity of cytochrome P450 isoforms 1A2 (CYP1A2) and 2C9 (CYP2C9). METHODS Probe substrates, phenacetin (CYP1A2), and tolbutamide (CYP2C9) were incubated with human liver microsomes and the metabolites were analyzed by liquid chromatography/mass spectrometry using electrospray ionization in positive or negative mode. Glipizide was used as the internal standard in both modes. The inhibitory potential of fluoroquinolones on CYP1A2 and CYP2C9 was investigated. RESULTS The IC50 values (micromol/L) determined with the cocktail were in agreement with individual probe substrates (alpha-naphthoflavone: 0.27 vs 0.26; sulfaphenazole: 0.49 vs 0.37). Ciprofloxacin showed weak inhibition on both the activity of CYP1A2 (IC50 135 micromol/L) and CYP2C9 (IC50 180 micromol/L), whereas levofloxacin inhibited only CYP2C9 (IC50 210 micromol/L). Caderofloxacin, antofloxacin, moxifloxacin, and gatifloxacin showed little or no inhibition on the activity of CYP1A2 or CYP2C9 when tested at comparable concentrations (0-200 mg/L). CONCLUSION Caderofloxacin, antofloxacin, moxifloxacin, and gatifloxacin are negligible inhibitors to CYP1A2 and CYP2C9. The in vitro system can be used as a high-throughput model to screen similar compounds for the early identification of drug-drug interaction potential.
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Affiliation(s)
- Li Zhang
- Institute of Clinical Pharmacology, Peking University First Hospital, Beijing 100191, China
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An automated, high-throughput, 384 well Cytochrome P450 cocktail IC50 assay using a rapid resolution LC-MS/MS end-point. J Pharm Biomed Anal 2008; 48:92-9. [PMID: 18584988 DOI: 10.1016/j.jpba.2008.05.011] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2008] [Revised: 05/01/2008] [Accepted: 05/09/2008] [Indexed: 11/23/2022]
Abstract
The current study focused on the development of an automated IC50 cocktail assay in a miniaturized 384 well assay format. This was developed in combination with a significantly shorter high pressure liquid chromatography (HPLC) separation and liquid chromatography-mass spectrometry (LC-MS/MS) run-time; than those currently reported in the literature. The 384-well assay used human liver microsomes in conjunction with a cocktail of probe substrates metabolized by the five major CYPs (tacrine for CYP1A2, diclofenac for CYP2C9, (S)-mephenytoin for CYP2C19, dextromethorphan for CYP2D6 and midazolam for CYP3A4). To validate the usefulness of the automated and analytical methodologies, IC50 determinations were performed for a series of test compounds known to exhibit inhibition across these five major P450s. Eight compounds (sertraline, disulfuram, ticlopidine fluconazole, fluvoxamine, ketoconazole, miconazole, paroxetine, flunitrazepam) were studied as part of a cocktail assay, and against each CYPs individually. The data showed that the IC50s generated with cocktail incubations did not differ to a great extent from those obtained in the single probe experiments and hence unlikely to significantly influence the predicted clinical DDI risk. In addition the present method offered a significant advantage over some of the existing cocktail analytical methodology in that separation can be achieved with run times as short as 1 min without compromising data integrity. Although numerous studies have been reported to measure CYP inhibition in a cocktail format the need to support growing discovery libraries not only relies on higher throughput assays but quicker analytical run times. The current study reports a miniaturized high-throughput cocktail IC50 assay, in conjunction with a robust, rapid resolution LC-MS/MS end-point offered increased sample throughput without compromising analytical sensitivity or analyte resolution.
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Kool J, van Liempd SM, Ramautar R, Schenk T, Meerman JHN, Irth H, Commandeur JNM, Vermeulen NPE. Development of a novel cytochrome p450 bioaffinity detection system coupled online to gradient reversed-phase high-performance liquid chromatography. ACTA ACUST UNITED AC 2005; 10:427-36. [PMID: 16093552 DOI: 10.1177/1087057105274904] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A high-resolution screening platform, coupling online affinity detection for mammalian cytochrome P450s (Cyt P450s) to gradient reversed-phase high-performance liquid chromatography (HPLC), is described. To this end, the online Cyt P450 enzyme affinity detection (EAD) system was optimized for enzyme (beta-NF-induced rat liver microsomes), probe substrate (ethoxyresorufine), and organic modifier (methanol or acetonitrile). The optimized Cyt P450 EAD system has first been evaluated in a flow injection analysis (FIA) mode with 7 known ligands of Cyt P450 1A1/1A2 (alpha-naphthoflavone, beta-naphthoflavone, ellipticine, 9-hydroxy-ellipticine, fluvoxamine, caffein, and phenacetin). Subsequently, IC50 values were online in FIA-mode determined and compared with those obtained with standardmicrosomal assay conditions. The IC50 values obtained with the online Cyt P450 EAD system agreed well with the IC50 values obtained in the standard assays. For high affinity ligands of Cyt P450 1A1/1A2, detection limits of 1 to 3 pmol injected (n=3; signal to noise [S/N]=3) were obtained. The individual inhibitory properties of ligands in mixtures of the ligands were subsequently investigated using an optimized Cyt P450 EAD system online coupled to gradient HPLC. Using the integrated online gradient HPLC Cyt P450 EAD platform, detection limits of 10 to 25 pmol injected (n=1; S/N=3) were obtained for high-affinity ligands. It is concluded that this novel screening technology offers new perspectives for rapid and sensitive screening of individual compounds in mixtures exhibiting affinity for liver microsomal Cyt P450s.
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Affiliation(s)
- Jeroen Kool
- LACDR-Division of Molecular Toxicology, Department of Pharmacochemistry, Vrije Universiteit, Amsterdam, the Netherlands
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Kong R. 17 LC/MS application in high-throughput adme screen. SEP SCI TECHNOL 2005. [DOI: 10.1016/s0149-6395(05)80061-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Hu YZ, Yao TW. In vitro metabolism and inductive or inhibitive effect of DL111 on rat cytochrome P4501A enzyme. Chem Biol Interact 2004; 147:109-17. [PMID: 15013813 DOI: 10.1016/j.cbi.2003.11.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/20/2003] [Indexed: 11/21/2022]
Abstract
In vitro metabolism and the inductive or inhibitive effect of DL111, a non-hormonal early pregnancy-terminating agent, toward cytochrome P450 (CYP) enzymes in rat liver microsomes were studied. In vitro metabolism of DL111 was performed in different rat liver microsomes (pretreated with phenobarbital (PB), dexamethasone (Dex), beta-naphthoflavone (BNF), DL111, respectively) and the catalytic abilities of these microsomes for DL111 were compared with control group. DL111 was well metabolized in microsomes pretreated with beta-naphthoflavone and itself. The K(m) and V(max) was 41.76 +/- 3.26 microM and 15.34 +/- 1.03 nM min(-1) mg(-1) protein for beta-naphthoflavone group, 48.17 +/- 6.06 microM and 17.54 +/- 1.79 nM min(-1)mg(-1) protein for DL111 group, 77.81 +/- 4.73 microM and 3.087 +/- 0.202 nM min(-1)mg(-1) protein for control group, respectively. The rats were pretreated intraperitoneally with the same daily dose of DL111 for different days. The DL111-pretreated microsomal enzymatic activities were evaluated by measuring the metabolic abilities for specific substrates of various enzymes. The results showed that DL111 had the same inductive function as beta-naphthoflavone (the specific inducer of CYP1A) toward rat liver microsomes. The inhibitive effect of DL111 on CYP1A was investigated by coincubating DL111 with the specific substrates of CYP1A-ethoxyresorufin or phenacetin in the microsome induced by beta-naphthoflavone, and the inhibitive level was compared with fluvoxamine (Flu), the specific inhibitor of CYP1A. DL111 inhibited significantly the metabolism of phenacetin and ethoxyresorufin with the inhibition constant (K(i)) 6.836 +/- 0.10 and 1.222 +/- 0.230 microM, respectively and its inhibition potential on CYP1A was higher than fluvoxamine.
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Affiliation(s)
- Yun-Zhen Hu
- Department of Pharmaceutical Analysis and Drug Metabolism, College of Pharmaceutical Sciences, Zhejiang University, 353 Yan'an Road, Hangzhou, Zhejiang 310031, PR China
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Kerns EH, Kleintop T, Little D, Tobien T, Mallis L, Di L, Hu M, Hong Y, McConnell OJ. Integrated high capacity solid phase extraction-MS/MS system for pharmaceutical profiling in drug discovery. J Pharm Biomed Anal 2004; 34:1-9. [PMID: 14738913 DOI: 10.1016/j.japna.2003.03.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
A method is described for use in analysis of samples from pharmaceutical profiling of early drug discovery compounds. The method consists of a high capacity autosampler which injects samples into one of two solid phase extraction columns operated in parallel for alternating trapping, washing and elution into a tandem quadrupole mass spectrometer operated in multiple reaction monitoring (MRM) MS/MS mode. A primary method, which is useful for 80-90% of compounds, and a secondary method, which is useful for a majority of the remaining compounds, are described. No analytical HPLC column is used and the analysis rate is approximately 50 samples/h. Specificity is obtained using MRM analysis. Application of the method for high capacity analysis of metabolic stability samples is described.
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Current literature in mass spectrometry. JOURNAL OF MASS SPECTROMETRY : JMS 2001; 36:838-848. [PMID: 11473409 DOI: 10.1002/jms.94] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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