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Guan Q, Xing S, Wang L, Zhu J, Guo C, Xu C, Zhao Q, Wu Y, Chen Y, Sun H. Triazoles in Medicinal Chemistry: Physicochemical Properties, Bioisosterism, and Application. J Med Chem 2024; 67:7788-7824. [PMID: 38699796 DOI: 10.1021/acs.jmedchem.4c00652] [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: 05/05/2024]
Abstract
Triazole demonstrates distinctive physicochemical properties, characterized by weak basicity, various dipole moments, and significant dual hydrogen bond acceptor and donor capabilities. These features are poised to play a pivotal role in drug-target interactions. The inherent polarity of triazole contributes to its lower logP, suggesting the potential improvement in water solubility. The metabolic stability of triazole adds additional value to drug discovery. Moreover, the metal-binding capacity of the nitrogen atom lone pair electrons of triazole has broad applications in the development of metal chelators and antifungal agents. This Perspective aims to underscore the unique physicochemical attributes of triazole and its application. A comparative analysis involving triazole isomers and other heterocycles provides guiding insights for the subsequent design of triazoles, with the hope of offering valuable considerations for designing other heterocycles in medicinal chemistry.
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Affiliation(s)
- Qianwen Guan
- School of Pharmacy, China Pharmaceutical University, Nanjing 211198, People's Republic of China
| | - Shuaishuai Xing
- School of Pharmacy, China Pharmaceutical University, Nanjing 211198, People's Republic of China
| | - Lei Wang
- School of Pharmacy, China Pharmaceutical University, Nanjing 211198, People's Republic of China
| | - Jiawei Zhu
- School of Pharmacy, China Pharmaceutical University, Nanjing 211198, People's Republic of China
| | - Can Guo
- School of Pharmacy, China Pharmaceutical University, Nanjing 211198, People's Republic of China
| | - Chunlei Xu
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, People's Republic of China
| | - Qun Zhao
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, People's Republic of China
| | - Yulan Wu
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, People's Republic of China
| | - Yao Chen
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, People's Republic of China
| | - Haopeng Sun
- School of Pharmacy, China Pharmaceutical University, Nanjing 211198, People's Republic of China
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2
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Tonero ME, Li Z, Reinhart JM. Cytochrome P450 reaction phenotyping of itraconazole hydroxylation in the dog. J Vet Pharmacol Ther 2022; 45:255-264. [PMID: 35389533 DOI: 10.1111/jvp.13058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 02/21/2022] [Accepted: 03/28/2022] [Indexed: 11/30/2022]
Abstract
Itraconazole (ITZ) is an important drug in the treatment of superficial and deep mycoses in dogs. Its primary metabolite is hydroxy-itraconazole, which has antifungal activity similar to the parent compound. The purpose of this study was to identify the cytochrome P450 enzyme (CYP) isoform(s) responsible for ITZ hydroxylation in canine liver. Reaction kinetics for ITZ hydroxylation were determined in a panel of canine recombinant CYPs and dog liver microsomes (DLMs). Findings were confirmed using CYP isoform-specific inhibitors in rCYPs and DLMs. In rCYP experiments, CYP2D15 and CYP3A12 had highest activity for ITZ hydroxylation. In inhibitor experiments, quinidine and erythromycin inhibited ITZ hydroxylation in CYP2D15 and CYP3A12, respectively, in an isoform-specific manner. In DLMs, quinidine and erythromycin combined inhibited ITZ hydroxylation more than erythromycin alone but not quinidine alone. However, this may be related to inhibitor potency rather than the contribution of the individual CYP isoforms to the reaction. These findings support a role for CYP2D15 and CYP3A12 in ITZ biotransformation in canine liver.
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Affiliation(s)
- Matthew E Tonero
- Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois, Urbana, Illinois, USA
| | - Zhong Li
- Roy J. Carver Biotechnology Center, University of Illinois, Urbana, Illinois, USA
| | - Jennifer M Reinhart
- Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois, Urbana, Illinois, USA
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3
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Wu YJ, Meanwell NA. Geminal Diheteroatomic Motifs: Some Applications of Acetals, Ketals, and Their Sulfur and Nitrogen Homologues in Medicinal Chemistry and Drug Design. J Med Chem 2021; 64:9786-9874. [PMID: 34213340 DOI: 10.1021/acs.jmedchem.1c00790] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Acetals and ketals and their nitrogen and sulfur homologues are often considered to be unconventional and potentially problematic scaffolding elements or pharmacophores for the design of orally bioavailable drugs. This opinion is largely a function of the perception that such motifs might be chemically unstable under the acidic conditions of the stomach and upper gastrointestinal tract. However, even simple acetals and ketals, including acyclic molecules, can be sufficiently robust under acidic conditions to be fashioned into orally bioavailable drugs, and these structural elements are embedded in many effective therapeutic agents. The chemical stability of molecules incorporating geminal diheteroatomic motifs can be modulated by physicochemical design principles that include the judicious deployment of proximal electron-withdrawing substituents and conformational restriction. In this Perspective, we exemplify geminal diheteroatomic motifs that have been utilized in the discovery of orally bioavailable drugs or drug candidates against the backdrop of understanding their potential for chemical lability.
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Affiliation(s)
- Yong-Jin Wu
- Small Molecule Drug Discovery, Bristol Myers Squibb Research and Early Development, 100 Binney Street, Cambridge, Massachusetts 02142, United States
| | - Nicholas A Meanwell
- Department of Discovery and Chemistry and Molecular Technologies, Bristol-Myers Squibb PRI, PO Box 4000, Princeton, New Jersey 08543-4000, United States
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4
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Van Damme E, De Meyer S, Bojkova D, Ciesek S, Cinatl J, De Jonghe S, Jochmans D, Leyssen P, Buyck C, Neyts J, Van Loock M. In vitro activity of itraconazole against SARS-CoV-2. J Med Virol 2021; 93:4454-4460. [PMID: 33666253 PMCID: PMC8014624 DOI: 10.1002/jmv.26917] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 02/11/2021] [Accepted: 02/27/2021] [Indexed: 12/16/2022]
Abstract
Although vaccination campaigns are currently being rolled out to prevent coronavirus disease (COVID-19), antivirals will remain an important adjunct to vaccination. Antivirals against coronaviruses do not exist, hence global drug repurposing efforts have been carried out to identify agents that may provide clinical benefit to patients with COVID-19. Itraconazole, an antifungal agent, has been reported to have activity against animal coronaviruses. Using cell-based phenotypic assays, the in vitro antiviral activity of itraconazole and 17-OH itraconazole was assessed against clinical isolates from a German and Belgian patient infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Itraconazole demonstrated antiviral activity in human Caco-2 cells (EC50 = 2.3 µM; 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay). Similarly, its primary metabolite, 17-OH itraconazole, showed inhibition of SARS-CoV-2 activity (EC50 = 3.6 µM). Remdesivir inhibited viral replication with an EC50 = 0.4 µM. Itraconazole and 17-OH itraconazole resulted in a viral yield reduction in vitro of approximately 2-log10 and approximately 1-log10 , as measured in both Caco-2 cells and VeroE6-eGFP cells, respectively. The viral yield reduction brought about by remdesivir or GS-441524 (parent nucleoside of the antiviral prodrug remdesivir; positive control) was more pronounced, with an approximately 3-log10 drop and >4-log10 drop in Caco-2 cells and VeroE6-eGFP cells, respectively. Itraconazole and 17-OH itraconazole exert in vitro low micromolar activity against SARS-CoV-2. Despite the in vitro antiviral activity, itraconazole did not result in a beneficial effect in hospitalized COVID-19 patients in a clinical study (EudraCT Number: 2020-001243-15).
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Affiliation(s)
| | | | - Denisa Bojkova
- Institute of Medical Virology, University Hospital Frankfurt, Goethe University, Frankfurt, Germany
| | - Sandra Ciesek
- Institute of Medical Virology, University Hospital Frankfurt, Goethe University, Frankfurt, Germany.,German Center for Infection Research (DZIF), Braunschweig, Germany
| | - Jindrich Cinatl
- Institute of Medical Virology, University Hospital Frankfurt, Goethe University, Frankfurt, Germany
| | - Steven De Jonghe
- KU Leuven, Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory of Virology and Chemotherapy, Leuven, Belgium
| | - Dirk Jochmans
- KU Leuven, Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory of Virology and Chemotherapy, Leuven, Belgium
| | - Pieter Leyssen
- KU Leuven, Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory of Virology and Chemotherapy, Leuven, Belgium
| | | | - Johan Neyts
- KU Leuven, Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory of Virology and Chemotherapy, Leuven, Belgium
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5
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Matsumoto S, Uehara S, Kamimura H, Ikeda H, Maeda S, Hattori M, Nishiwaki M, Kato K, Yamazaki H. Human total clearance values and volumes of distribution of typical human cytochrome P450 2C9/19 substrates predicted by single-species allometric scaling using pharmacokinetic data sets from common marmosets genotyped for P450 2C19. Xenobiotica 2021; 51:479-493. [PMID: 33455494 DOI: 10.1080/00498254.2020.1871113] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Common marmosets (Callithrix jacchus) are small non-human primates that genetically lack cytochrome P450 2C9 (CYP2C9). Polymorphic marmoset CYP2C19 compensates by mediating oxidations of typical human CYP2C9/19 substrates.Twenty-four probe substrates were intravenously administered in combinations to marmosets assigned to extensive or poor metaboliser (PM) groups by CYP2C19 genotyping. Eliminations from plasma of cilomilast, phenytoin, repaglinide, tolbutamide, and S-warfarin in the CYP2C19 PM group were significantly slow; these drugs are known substrates of human CYP2C8/9/19.Human total clearance values and volumes of distribution of the 24 test compounds were extrapolated using single-species allometric scaling with experimental data from marmosets and found to be mostly comparable with the reported values.Human total clearance values and volumes of distribution of 15 of the 24 test compounds similarly extrapolated using reported data sets from cynomolgus or rhesus monkeys were comparable to the present predicted results, especially to those based on data from PM marmosets.These results suggest that single-species allometric scaling using marmosets, being small, has advantages over multiple-species-based allometry and could be applicable for pharmacokinetic predictions at the discovery stage of drug development.
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Affiliation(s)
- Shogo Matsumoto
- Pharmaceutical Research Labs., Meiji Seika Pharma Co., Ltd., Yokohama, Japan
| | - Shotaro Uehara
- Central Institute for Experimental Animals, Kawasaki, Japan.,Pharmaceutical University, Machida, Tokyo, Japan
| | - Hidetaka Kamimura
- Central Institute for Experimental Animals, Kawasaki, Japan.,Business Promotion Dept., CLEA Japan, Inc., Tokyo, Japan
| | - Hiroshi Ikeda
- Tokyo Animal & Diet Dept., CLEA Japan, Inc., Tokyo, Japan
| | - Satoshi Maeda
- Yaotsu Breeding Center, CLEA Japan, Inc., Gifu, Japan
| | | | - Megumi Nishiwaki
- Fuji Technical Service Center, CLEA Japan, Inc.., Shizuoka, Japan
| | - Kazuhiko Kato
- Pharmaceutical Research Labs., Meiji Seika Pharma Co., Ltd., Yokohama, Japan
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6
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Guengerich FP, McCarty KD, Chapman JG. Kinetics of cytochrome P450 3A4 inhibition by heterocyclic drugs defines a general sequential multistep binding process. J Biol Chem 2021; 296:100223. [PMID: 33449875 PMCID: PMC7948456 DOI: 10.1074/jbc.ra120.016855] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 12/16/2020] [Accepted: 12/21/2020] [Indexed: 11/21/2022] Open
Abstract
Cytochrome P450 (P450) 3A4 is the enzyme most involved in the metabolism of drugs and can also oxidize numerous steroids. This enzyme is also involved in one-half of pharmacokinetic drug-drug interactions, but details of the exact mechanisms of P450 3A4 inhibition are still unclear in many cases. Ketoconazole, clotrimazole, ritonavir, indinavir, and itraconazole are strong inhibitors; analysis of the kinetics of reversal of inhibition with the model substrate 7-benzoyl quinoline showed lag phases in several cases, consistent with multiple structures of P450 3A4 inhibitor complexes. Lags in the onset of inhibition were observed when inhibitors were added to P450 3A4 in 7-benzoyl quinoline O-debenzylation reactions, and similar patterns were observed for inhibition of testosterone 6β-hydroxylation by ritonavir and indinavir. Upon mixing with inhibitors, P450 3A4 showed rapid binding as judged by a spectral shift with at least partial high-spin iron character, followed by a slower conversion to a low-spin iron-nitrogen complex. The changes were best described by two intermediate complexes, one being a partial high-spin form and the second another intermediate, with half-lives of seconds. The kinetics could be modeled in a system involving initial loose binding of inhibitor, followed by a slow step leading to a tighter complex on a multisecond time scale. Although some more complex possibilities cannot be dismissed, these results describe a system in which conformationally distinct forms of P450 3A4 bind inhibitors rapidly and two distinct P450-inhibitor complexes exist en route to the final enzyme-inhibitor complex with full inhibitory activity.
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Affiliation(s)
- F Peter Guengerich
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee, USA.
| | - Kevin D McCarty
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Jesse G Chapman
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
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7
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Lautz LS, Jeddi MZ, Girolami F, Nebbia C, Dorne JLCM. Metabolism and pharmacokinetics of pharmaceuticals in cats (Felix sylvestris catus) and implications for the risk assessment of feed additives and contaminants. Toxicol Lett 2020; 338:114-127. [PMID: 33253781 DOI: 10.1016/j.toxlet.2020.11.014] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 11/16/2020] [Accepted: 11/19/2020] [Indexed: 01/25/2023]
Abstract
In animal health risk assessment, hazard characterisation of feed additives has been often using the default uncertainty factor (UF) of 100 to translate a no-observed-adverse-effect level in test species (rat, mouse, dog, rabbit) to a 'safe' level of chronic exposure in farm and companion animal species. Historically, both 10-fold factors have been further divided to include chemical-specific data in both dimensions when available. For cats (Felis Sylvestris catus), an extra default UF of 5 is applied due to the species' deficiency in particularly glucuronidation and glycine conjugation. This paper aims to assess the scientific basis and validity of the UF for inter-species differences in kinetics (4.0) and the extra UF applied for cats through a comparison of kinetic parameters between rats and cats for 30 substrates of phase I and phase II metabolism. When the parent compound undergoes glucuronidation the default factor of 4.0 is exceeded, with exceptions for zidovudine and S-carprofen. Compounds that were mainly renally excreted did not exceed the 4.0-fold default. Mixed results were obtained for chemicals which are metabolised by CYP3A in rats. When chemicals were administered intravenously the 4.0-fold default was not exceeded with the exception of clomipramine, lidocaine and alfentanil. The differences seen after oral administration might be due to differences in first-pass metabolism and bioavailability. Further work is needed to further characterise phase I, phase II enzymes and transporters in cats to support the development of databases and in silico models to support hazard characterisation of chemicals particularly for feed additives.
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Affiliation(s)
- L S Lautz
- Radboud University Nijmegen, Houtlaan 4, 6525 XZ Nijmegen, the Netherlands
| | - M Z Jeddi
- European Food Safety Authority, Scientific Committee and Emerging Risks Unit, Via Carlo Magno, 1A, 43126 Parma, Italy
| | - F Girolami
- University of Torino, Department of Veterinary Sciences, Largo P. Braccini 2, 10095 Grugliasco, Italy
| | - C Nebbia
- University of Torino, Department of Veterinary Sciences, Largo P. Braccini 2, 10095 Grugliasco, Italy
| | - J L C M Dorne
- European Food Safety Authority, Scientific Committee and Emerging Risks Unit, Via Carlo Magno, 1A, 43126 Parma, Italy.
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8
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Elkheir LYM, Haroun R, Mohamed MA, Fahal AH. Madurella mycetomatis causing eumycetoma medical treatment: The challenges and prospects. PLoS Negl Trop Dis 2020; 14:e0008307. [PMID: 32853199 PMCID: PMC7452721 DOI: 10.1371/journal.pntd.0008307] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Lamis Y. M. Elkheir
- The Mycetoma Research Centre, University of Khartoum, Khartoum, Sudan
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Khartoum, Khartoum, Sudan
| | - Rayan Haroun
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Khartoum, Khartoum, Sudan
| | - Magdi Awadalla Mohamed
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Khartoum, Khartoum, Sudan
- Department of Pharmaceutical Chemistry, College of Pharmacy, Jouf University, Jouf, KSA
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9
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In vivo evaluation of the efficacy, toxicity and biodistribution of PLGA-DMSA nanoparticles loaded with itraconazole for treatment of paracoccidioidomycosis. J Drug Deliv Sci Technol 2018. [DOI: 10.1016/j.jddst.2018.02.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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10
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Metabolomics-assisted metabolite profiling of itraconazole in human liver preparations. J Chromatogr B Analyt Technol Biomed Life Sci 2018. [PMID: 29524695 DOI: 10.1016/j.jchromb.2018.02.041] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Itraconazole (ITZ) is a first-generation triazole-containing antifungal agent that effectively treats various fungal infections. As ITZ has a better safety profile than that of ketoconazole (KCZ), ITZ has been used worldwide for over 25 years. However, few reports have explored the metabolic profile of ITZ, and the underlying mechanism of ITZ-induced liver injury is not clearly understood. In the present study, we revisited ITZ metabolism in humans, using a non-targeted metabolomics approach, and identified several novel metabolic pathways including O-dearylation, piperazine oxidation, and piperazine-N,N'-deethylation. Furthermore, we explored the formation of reactive ITZ metabolites using trapping agents as surrogates, to assess the possibility of metabolism-mediated toxicity. We found that ITZ and its metabolites did not form any adducts with nucleophiles including glutathione, potassium cyanide, and semicarbazide. The present study expands our knowledge of ITZ metabolism and supports the suggestion that ITZ has a better safety profile than that of KCZ in terms of metabolism-mediated toxicity.
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Krasulova K, Dvorak Z, Anzenbacher P. In vitro analysis of itraconazole cis-diastereoisomers inhibition of nine cytochrome P450 enzymes: stereoselective inhibition of CYP3A. Xenobiotica 2018; 49:36-42. [PMID: 29320899 DOI: 10.1080/00498254.2018.1425510] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
1. Itraconazole (ITZ), an antifungal azole derivate is a chiral drug that consists of four cis-diastereoisomers ((+)-2R,4S,2'R-ITZ-A; (+)-2R,4S,2'S-ITZ-B; (-)-2S,4R,2'S-ITZ-C and (-)-2S,4R,2'R-ITZ-D) which may differ in their pharmacokinetics and pharmacodynamics. 2. As ITZ is known as a CYP3A4 inhibitor causing severe drug-drug interaction, the inhibitory potencies of its individual optical isomers towards nine drug-metabolising cytochrome P450 (including CYP3A, CYP1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6 and CYP2E1), were investigated. 3. All ITZ diastereoisomers dose-dependently inhibited CYP3A activity in both used assays, midazolam and testosterone hydroxylation. The Ki values were assessed: for testosterone ITZ-A/0.085 µM; ITZ-B/0.91 µM, ITZ-C/0.20 µM and ITZ-D/0.022 µM; for midazolam ITZ-A/0.44 µM; ITZ-B/0.48 µM, ITZ-C/1.56 µM and ITZ-D/3.48 µM. The enzyme activity of CYP2C19 was moderately inhibited (IC50 30-53 µM), but in this case without large differences between the individual optical isomers. 4. The significant differences between diastereoisomers were presented. Antifungal potency of ITZ stereoisomers also differs so the potential enantiopure preparations of ITZ was not of interest.
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Affiliation(s)
- Kristyna Krasulova
- a Department of Pharmacology and Institute of Molecular and Translational Medicine , Faculty of Medicine, Palacky University , Olomouc , Czech Republic and
| | - Zdenek Dvorak
- b Department of Cell Biology and Genetics , Faculty of Science, Palacky University , Olomouc , Czech Republic
| | - Pavel Anzenbacher
- a Department of Pharmacology and Institute of Molecular and Translational Medicine , Faculty of Medicine, Palacky University , Olomouc , Czech Republic and
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Zhuang S, Zhang L, Zhan T, Lu L, Zhao L, Wang H, Morrone JA, Liu W, Zhou R. Binding Specificity Determines the Cytochrome P450 3A4 Mediated Enantioselective Metabolism of Metconazole. J Phys Chem B 2018; 122:1176-1184. [PMID: 29310431 DOI: 10.1021/acs.jpcb.7b11170] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cytochrome P450 3A4 (CYP3A4) is a promiscuous enzyme, mediating the biotransformations of ∼50% of clinically used drugs, many of which are chiral molecules. Probing the interactions between CYP3A4 and chiral chemicals is thus essential for the elucidation of molecular mechanisms of enantioselective metabolism. We developed a stepwise-restrained-molecular-dynamics (MD) method to model human CYP3A4 in a complex with cis-metconazole (MEZ) isomers and performed conventional MD simulations with a total simulation time of 2.2 μs to probe the molecular interactions. Our current study, which employs a combined experimental and theoretical approach, reports for the first time on the distinct conformational changes of CYP3A4 that are induced by the enantioselective binding of cis-MEZ enantiomers. CYP3A4 preferably metabolizes cis-RS MEZ over the cis-SR isomer, with the resultant enantiomer fraction for cis-MEZ increasing rapidly from 0.5 to 0.82. cis-RS MEZ adopts a more extended structure in the active pocket with its Cl atom exposed to the solvent, whereas cis-SR MEZ sits within the hydrophobic core of the active pocket. Free-energy-perturbation calculations indicate that unfavorable van der Waals interactions between the cis-MEZ isomers and the CYP3A4 binding pocket predominantly contribute to their binding-affinity differences. These results demonstrate that binding specificity determines the cytochrome P450 3A4 mediated enantioselective metabolism of cis-MEZ.
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Affiliation(s)
- Shulin Zhuang
- College of Environmental and Resource Sciences, Zhejiang University , Hangzhou 310058, China
| | - Leili Zhang
- Computational Biology Center, IBM TJ Watson Research Center , Yorktown Heights, New York 10598, United States
| | - Tingjie Zhan
- College of Environmental and Resource Sciences, Zhejiang University , Hangzhou 310058, China
| | - Liping Lu
- College of Environmental and Resource Sciences, Zhejiang University , Hangzhou 310058, China.,Institute of Quantitative Biology, Department of Physics, Zhejiang University , Hangzhou 310058, China
| | - Lu Zhao
- College of Environmental and Resource Sciences, Zhejiang University , Hangzhou 310058, China
| | - Haifei Wang
- College of Environmental and Resource Sciences, Zhejiang University , Hangzhou 310058, China
| | - Joseph A Morrone
- Computational Biology Center, IBM TJ Watson Research Center , Yorktown Heights, New York 10598, United States
| | - Weiping Liu
- College of Environmental and Resource Sciences, Zhejiang University , Hangzhou 310058, China
| | - Ruhong Zhou
- Computational Biology Center, IBM TJ Watson Research Center , Yorktown Heights, New York 10598, United States.,Department of Chemistry, Columbia University , New York, New York 10027, United States
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Soleymani S, Bahramsoltani R, Rahimi R, Abdollahi M. Clinical risks of St John’s Wort (Hypericum perforatum) co-administration. Expert Opin Drug Metab Toxicol 2017; 13:1047-1062. [DOI: 10.1080/17425255.2017.1378342] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Samaneh Soleymani
- Department of Traditional Pharmacy, School of Traditional Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Roodabeh Bahramsoltani
- Department of Traditional Pharmacy, School of Traditional Medicine, Tehran University of Medical Sciences, Tehran, Iran
- PhytoPharmacology Interest Group (PPIG), Universal Scientific Education and Research Network (USERN), Tehran, Iran
| | - Roja Rahimi
- Department of Traditional Pharmacy, School of Traditional Medicine, Tehran University of Medical Sciences, Tehran, Iran
- Evidence-Based Medicine Group, Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Abdollahi
- Toxicology and Diseases Group, Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran, Iran
- Department of Toxicology and Pharmacology, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
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14
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Molecular docking simulations and GRID-independent molecular descriptor (GRIND) analysis to probe stereoselective interactions of CYP3A4 inhibitors. Med Chem Res 2017. [DOI: 10.1007/s00044-017-1933-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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15
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Stepankova M, Pastorkova B, Bachleda P, Dvorak Z. Itraconazole cis-diastereoisomers activate aryl hydrocarbon receptor AhR and pregnane X receptor PXR and induce CYP1A1 in human cell lines and human hepatocytes. Toxicology 2017; 383:40-49. [PMID: 28390928 DOI: 10.1016/j.tox.2017.04.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 03/24/2017] [Accepted: 04/03/2017] [Indexed: 12/27/2022]
Abstract
Triazole antimycotic itraconazole contains in its structure three chiral centres; therefore, it forms eight stereoisomers. Commercial preparations of itraconazole are a mixture of four cis-diastereoisomers. There is much evidence that efficacy, adverse effects, and toxicity of chiral drugs may be stereospecific. Therefore, we have prepared 4 pure cis-diastereoisomers of itraconazole and investigated their effects on transcriptional activities of xenoreceptors aryl hydrocarbon receptor AhR and pregnane X receptor PXR. Gene reporter assays showed that itraconazole dose-dependently activated both AhR and PXR, and the activation of AhR but not of PXR was enantiospecific. Itraconazole diastereoisomers transformed AhR and PXR into their DNA-binding forms, as demonstrated by electromobility shift assays. Cytochrome P450 CYP1A1 mRNA and protein were induced by itraconazole diastereoisomers in human hepatoma cells HepG2, human skin cells HaCaT, and in primary human hepatocytes. The expression of CYP3A4 in human intestinal LS180 cells was not influenced by itraconazole, but we observed downregulation of CYP3A4 in human hepatocytes. Collectively, we show that itraconazole is a dual activator of AhR and PXR, with differential effects on the target genes for xenoreceptors. The enantiospecific pattern was observed only in gene reporter assays for AhR. The data presented here might be of toxicological and clinical importance.
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Affiliation(s)
- Martina Stepankova
- Department of Cell Biology and Genetics, Faculty of Science, Palacky University, Slechtitelu 27, 783 71 Olomouc, Czech Republic
| | - Barbora Pastorkova
- Department of Cell Biology and Genetics, Faculty of Science, Palacky University, Slechtitelu 27, 783 71 Olomouc, Czech Republic
| | - Petr Bachleda
- 2nd Department of Surgery, University Hospital Olomouc, I.P. Pavlova 6, 775 20 Olomouc, Czech Republic
| | - Zdenek Dvorak
- Department of Cell Biology and Genetics, Faculty of Science, Palacky University, Slechtitelu 27, 783 71 Olomouc, Czech Republic.
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16
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Maincent JP, Najvar LK, Kirkpatrick WR, Huang S, Patterson TF, Wiederhold NP, Peters JI, Williams RO. Modified release itraconazole amorphous solid dispersion to treat Aspergillus fumigatus: importance of the animal model selection. Drug Dev Ind Pharm 2016; 43:264-274. [PMID: 27645428 DOI: 10.1080/03639045.2016.1236811] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Previously, modified release itraconazole in the form of a melt-extruded amorphous solid dispersion based on a pH dependent enteric polymer combined with hydrophilic additives (HME-ITZ), exhibited improved in vitro dissolution properties. These properties agreed with pharmacokinetic results in rats showing high and sustained itraconazole (ITZ) systemic levels. The objective of the present study was to better understand the best choice of rodent model for evaluating the pharmacokinetic and efficacy of this orally administered modified release ITZ dosage form against invasive Aspergillus fumigatus. A mouse model and a guinea pig model were investigated and compared to results previously published. In the mouse model, despite similar levels as previously reported values, plasma and lung levels were variable and fungal burden was not statistically different for placebo controls, HME-ITZ and Sporanox® (ITZ oral solution). This study demonstrated that the mouse model is a poor choice for studying modified release ITZ dosage forms based on pH dependent enteric polymers due to low fluid volume available for dissolution and low intestinal pH. To the contrary, guinea pig was a suitable model to evaluate modified release ITZ dosage forms. Indeed, a significant decrease in lung fungal burden as a result of high and sustained ITZ tissue levels was measured. Sufficiently high intestinal pH and fluids available for dissolution likely facilitated the dissolution process. Despite high ITZ tissue level, the primary therapeutic agent voriconazole exhibited an even more pronounced decrease in fungal burden due to its reported higher clinical efficacy specifically against Aspergillus fumigatus.
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Affiliation(s)
- Julien P Maincent
- a College of Pharmacy , The University of Texas at Austin , Austin , TX , USA
| | - Laura K Najvar
- b University of Texas Health Science Center , San Antonio , TX , USA
| | | | - Siyuan Huang
- a College of Pharmacy , The University of Texas at Austin , Austin , TX , USA
| | | | | | - Jay I Peters
- b University of Texas Health Science Center , San Antonio , TX , USA
| | - Robert O Williams
- a College of Pharmacy , The University of Texas at Austin , Austin , TX , USA
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17
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Lu XF, Zhan J, Zhou Y, Bi KS, Chen XH. Use of a semi-physiological pharmacokinetic model to investigate the influence of itraconazole on tacrolimus absorption, distribution and metabolism in mice. Xenobiotica 2016; 47:752-762. [PMID: 27533047 DOI: 10.1080/00498254.2016.1226003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
1. The aim of this study was to investigate the influence of itraconazole (ITCZ) on tacrolimus absorption, distribution and metabolism by developing a semi-physiological pharmacokinetic model of tacrolimus in mice. 2. Mice were randomly divided into four groups, namely control group (CG, taking 3 mg kg-1 tacrolimus only), low-dose group (LDG, taking tacrolimus with 12.5 mg kg-1 ITCZ), medium-dose group (MDG, taking tacrolimus with 25 mg kg-1 ITCZ) and high-dose group (HDG, taking tacrolimus with 50 mg kg-1 ITCZ). 3. Liver clearance (CLli) decreased significantly (**p < 0.01) in LDG (35.3%), MDG (45.2%) and HDG (58.7%) mice compared to CG mice. With respect to gut clearance (CLgu), significant (**p < 0.01) decrease was also revealed in LDG (35.9%), MDG (50.2%) and HDG (64.6%) mice. A significant (**p < 0.01) higher tacrolimus brain-to-blood partition coefficient (Kt,br) was found in MDG (25.3%) and HDG (55.9%) mice than in CG mice. Moreover, a significant (*p < 0.05) increase (16.3%) was found in the absorption rate constant (Ka) in HDG mice compared to CG mice. There was a significant (**p < 0.01) association between ITCZ dose and the change in CLgu (ΔCLgu, r= -0.790), the change in CLli (ΔCLli, r= -0.787) and the change in Kt,br (ΔKt,br, r = 0.727), while the association between ITCZ dose and the change in Ka (ΔKa) was not significant (p > 0.05). 4. These findings could be useful in predicting the efficacy and toxicity of tacrolimus, and drug-drug interaction of ITCZ and tarcolimus in human.
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Affiliation(s)
- Xue-Feng Lu
- a Department of Pharmaceutical Analysis , School of Pharmacy, Shenyang Pharmaceutical University , Shenyang , China
| | - Jian Zhan
- b Department of Pharmaceutics , School of Pharmacy, Shenyang Pharmaceutical University , Shenyang , China , and
| | - Yang Zhou
- c Department of Measurement and Control , School of Physics, Liaoning University , Shenyang , China
| | - Kai-Shun Bi
- a Department of Pharmaceutical Analysis , School of Pharmacy, Shenyang Pharmaceutical University , Shenyang , China
| | - Xiao-Hui Chen
- a Department of Pharmaceutical Analysis , School of Pharmacy, Shenyang Pharmaceutical University , Shenyang , China
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18
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Kurka O, Kučera L, Bednář P. Analytical and semipreparative chiral separation ofcis-itraconazole on cellulose stationary phases by high-performance liquid chromatography. J Sep Sci 2016; 39:2736-45. [DOI: 10.1002/jssc.201600240] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Revised: 05/18/2016] [Accepted: 05/19/2016] [Indexed: 01/23/2023]
Affiliation(s)
- Ondřej Kurka
- Regional Centre of Advanced Technologies and Materials; Department of Analytical Chemistry; Faculty of Science; Palacký University; Olomouc Czech Republic
| | - Lukáš Kučera
- Regional Centre of Advanced Technologies and Materials; Department of Analytical Chemistry; Faculty of Science; Palacký University; Olomouc Czech Republic
| | - Petr Bednář
- Regional Centre of Advanced Technologies and Materials; Department of Analytical Chemistry; Faculty of Science; Palacký University; Olomouc Czech Republic
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Shim JS, Li RJ, Bumpus NN, Head SA, Kumar Pasunooti K, Yang EJ, Lv J, Shi W, Liu JO. Divergence of Antiangiogenic Activity and Hepatotoxicity of Different Stereoisomers of Itraconazole. Clin Cancer Res 2016; 22:2709-20. [PMID: 26801248 DOI: 10.1158/1078-0432.ccr-15-1888] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 12/30/2015] [Indexed: 11/16/2022]
Abstract
PURPOSE Itraconazole is a triazole antifungal drug that has recently been found to inhibit angiogenesis. Itraconazole is a relatively well-tolerated drug but shows hepatotoxicity in a small subset of patients. Itraconazole contains three chiral centers and the commercial itraconazole is composed of four cis-stereoisomers (named IT-A, IT-B, IT-C, and IT-D). We sought to determine whether the stereoisomers of itraconazole might differ in their antiangiogenic activity and hepatotoxicity. EXPERIMENTAL DESIGN We assessed in vitro antiangiogenic activity of itraconazole and each stereoisomer using human umbilical vein endothelial cell (HUVEC) proliferation and tube formation assays. We also determined their hepatotoxicity using primary human hepatocytes in vitro and a mouse model in vivo Mouse Matrigel plug and tumor xenograft models were used to evaluate in vivo antiangiogenic and antitumor activities of the stereoisomers. RESULTS Of the four stereoisomers contained in commercial itraconazole, we found that IT-A (2S,4R,2'R) and IT-C (2S,4R,2'S) were more potent for inhibition of angiogenesis than IT-B (2R,4S,2'R) and IT-D (2R,4S,2'S). Interestingly, IT-A and IT-B were more hepatotoxic than IT-C and IT-D. In mouse models, IT-C showed more potent antiangiogenic/antitumor activity with lower hepatotoxicity compared with itraconazole and IT-A. CONCLUSIONS These results demonstrate the segregation of influence of stereochemistry at different positions of itraconazole on its antiangiogenic activity and hepatotoxicity, with the 2 and 4 positions affecting the former and the 2' position affecting the latter. They also suggest that IT-C may be superior to the racemic mixture of itraconazole as an anticancer drug candidate due to its lower hepatotoxicity and improved antiangiogenic activity. Clin Cancer Res; 22(11); 2709-20. ©2016 AACR.
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Affiliation(s)
- Joong Sup Shim
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland. Faculty of Health Sciences, University of Macau, Taipa, Macau SAR, China
| | - Ruo-Jing Li
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Namandje N Bumpus
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland. Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Sarah A Head
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Kalyan Kumar Pasunooti
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Eun Ju Yang
- Faculty of Health Sciences, University of Macau, Taipa, Macau SAR, China
| | - Junfang Lv
- Faculty of Health Sciences, University of Macau, Taipa, Macau SAR, China
| | - Wei Shi
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland. Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas
| | - Jun O Liu
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland. Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland.
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20
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Lang B, Liu S, McGinity JW, Williams RO. Effect of hydrophilic additives on the dissolution and pharmacokinetic properties of itraconazole-enteric polymer hot-melt extruded amorphous solid dispersions. Drug Dev Ind Pharm 2015; 42:429-45. [PMID: 26355819 DOI: 10.3109/03639045.2015.1075031] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Hot-melt extrusion technology has been widely reported for producing amorphous solid dispersions of poorly water-soluble compounds. A number of studies revealed that enteric polymers containing ionizable groups are able to improve the physical stability and maintain drug supersaturation, thereby enhancing oral bioavailability. However, our previous studies found that itraconazole (ITZ)-enteric polymer amorphous solid dispersions are hydrophobic and poorly wettable. Moreover, drug release in an acidic environment (i.e. stomach) is very limited, indicating a narrow absorption window. In the present study, we investigated the effect of hydrophilic additives on the in vitro and in vivo performance of ITZ-enteric polymer amorphous solid dispersions. Incorporating Vitamin E TPGS into ITZ-HPMCAS amorphous solid dispersions significantly improved drug release in the acidic media. Surprisingly, a low concentration of Vitamin E TPGS also enhanced the degree of drug supersaturation in neutral pH media, which is unique as compared with other tested hydrophilic additives. This effect is not due to the solubilization of the surfactant. We further formulated the amorphous solid dispersions into tablet dosage forms and evaluated their performance in a bio-relevant dissolution media. Our optimized formulations exhibited drastically enhanced dissolution profiles as compared with the commercial ITZ product and ITZ amorphous solid dispersion without hydrophilic additive. In vivo study showed that Vitamin E TPGS induced rapid drug absorption after oral administration. Moreover, the elimination half-life of ITZ was prolonged due to the enzyme inhibition effect of Vitamin E TPGS.
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Affiliation(s)
- Bo Lang
- a Division of Pharmaceutics , College of Pharmacy, The University of Texas at Austin , Austin , TX , USA and
| | - Sha Liu
- a Division of Pharmaceutics , College of Pharmacy, The University of Texas at Austin , Austin , TX , USA and.,b Department of Pharmacology , Shandong University School of Medicine , Shandong , China
| | - James W McGinity
- a Division of Pharmaceutics , College of Pharmacy, The University of Texas at Austin , Austin , TX , USA and
| | - Robert O Williams
- a Division of Pharmaceutics , College of Pharmacy, The University of Texas at Austin , Austin , TX , USA and
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21
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Togashi M, Niioka T, Komatsuda A, Nara M, Okuyama S, Omokawa A, Abumiya M, Wakui H, Takahashi N, Miura M. Effect of CYP3A5 and ABCB1 polymorphisms on the interaction between tacrolimus and itraconazole in patients with connective tissue disease. Eur J Clin Pharmacol 2015; 71:1091-7. [PMID: 26184414 DOI: 10.1007/s00228-015-1901-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2015] [Accepted: 07/02/2015] [Indexed: 11/26/2022]
Abstract
PURPOSE The aim of this study was to investigate the effect of itraconazole (ITCZ), a potent inhibitor of CYP3A4 and P-glycoprotein, on the blood concentration 12 h after tacrolimus administration (C 12h) in relation to CYP3A5 6986A>G and ABCB1 3435C>T genotype status in patients with connective tissue disease (CTD). METHODS Eighty-one CTD patients taking tacrolimus (Prograf®) once daily at night (2100 hours) were enrolled in this study. Whole blood samples were collected 12 h after tacrolimus administration at steady state. RESULTS The dose-adjusted tacrolimus C 12h with or without ITCZ co-administration was significantly higher in patients with CYP3A5*3/*3 than in those with the CYP3A5*1 allele [CYP3A5 *1/*1 vs. *1/*3 vs. *3/*3 = 1.67 vs. 2.70 vs. 4.83 ng/mL/mg (P = 0.003) and 0.68 vs. 0.97 vs. 2.20 ng/mL/mg (P < 0.001), respectively], but differences were not observed for ABCB1 genotypes. However, there was no difference in the increase rate of the dose-adjusted C 12h of tacrolimus between CYP3A5 or ABCB1 genotypes (P = 0.378 and 0.259). On the other hand, reduction of the estimated glomerular filtration rate exhibited a correlation with the C 12h of tacrolimus after ITCZ co-administration (r = -0.482, P = 0.009). CONCLUSIONS In CYP3A5*3/*3 patients, because the metabolic pathway for tacrolimus occurs only through CYP3A4, the combination with ITCZ seems to lead to a higher risk of acute renal dysfunction. Therefore, we suggest that the target blood tacrolimus concentration be set as low as possible through dose-adjustment for patients with the CYP3A5*3/*3 allele.
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Affiliation(s)
- Masaru Togashi
- Department of Hematology, Nephrology, Rheumatology, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita, 010-8543, Japan
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22
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Conner KP, Vennam P, Woods CM, Krzyaniak MD, Bowman MK, Atkins WM. 1,2,3-Triazole-heme interactions in cytochrome P450: functionally competent triazole-water-heme complexes. Biochemistry 2012; 51:6441-57. [PMID: 22809252 DOI: 10.1021/bi300744z] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In comparison to imidazole (IMZ) and 1,2,4-triazole (1,2,4-TRZ), the isosteric 1,2,3-triazole (1,2,3-TRZ) is unrepresented among cytochrome P450 (CYP) inhibitors. This is surprising because 1,2,3-TRZs are easily obtained via "click" chemistry. To understand this underrepresentation of 1,2,3-TRZs among CYP inhibitors, thermodynamic and density functional theory computational studies were performed with unsubstituted IMZ, 1,2,4-TRZ, and 1,2,3-TRZ. The results indicate that the lower affinity of 1,2,3-TRZ for the heme iron includes a large unfavorable entropy term likely originating in solvent-1,2,3-TRZ interactions; the difference is not solely due to differences in the enthalpy of heme-ligand interactions. In addition, the 1,2,3-TRZ fragment was incorporated into a well-established CYP3A4 substrate and mechanism-based inactivator, 17-α-ethynylestradiol (17EE), via click chemistry. This derivative, 17-click, yielded optical spectra consistent with low-spin ferric heme iron (type II) in contrast to 17EE, which yields a high-spin complex (type I). Furthermore, the rate of CYP3A4-mediated metabolism of 17-click was comparable to that of 17EE, with a different regioselectivity. Surprisingly, continuous-wave electron paramagnetic resonance (EPR) and HYSCORE EPR spectroscopy indicate that 17-click does not displace water from the sixth axial ligand position of CYP3A4 as expected for a type II ligand. We propose a binding model in which 17-click pendant 1,2,3-TRZ hydrogen bonds with the sixth axial water ligand. The results demonstrate the potential for 1,2,3-TRZ to form metabolically labile water-bridged low-spin heme complexes, consistent with recent evidence that nitrogenous type II ligands of CYPs can be efficiently metabolized. The specific case of [CYP3A4·17-click] highlights the risk of interpreting CYP-ligand complex structure on the basis of optical spectra.
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Affiliation(s)
- Kip P Conner
- Department of Medicinal Chemistry, Box 357610, University of Washington, Seattle, WA 98195-7610, USA
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