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Sóskuti E, Szilvásy N, Temesszentandrási-Ambrus C, Urbán Z, Csíkvári O, Szabó Z, Kecskeméti G, Pusztai É, Gáborik Z. Applicability of MDR1 Overexpressing Abcb1KO-MDCKII Cell Lines for Investigating In Vitro Species Differences and Brain Penetration Prediction. Pharmaceutics 2024; 16:736. [PMID: 38931858 PMCID: PMC11207571 DOI: 10.3390/pharmaceutics16060736] [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: 04/30/2024] [Revised: 05/22/2024] [Accepted: 05/24/2024] [Indexed: 06/28/2024] Open
Abstract
Implementing the 3R initiative to reduce animal experiments in brain penetration prediction for CNS-targeting drugs requires more predictive in vitro and in silico models. However, animal studies are still indispensable to obtaining brain concentration and determining the prediction performance of in vitro models. To reveal species differences and provide reliable data for IVIVE, in vitro models are required. Systems overexpressing MDR1 and BCRP are widely used to predict BBB penetration, highlighting the impact of the in vitro system on predictive performance. In this study, endogenous Abcb1 knock-out MDCKII cells overexpressing MDR1 of human, mouse, rat or cynomolgus monkey origin were used. Good correlations between ERs of 83 drugs determined in each cell line suggest limited species specificities. All cell lines differentiated CNS-penetrating compounds based on ERs with high efficiency and sensitivity. The correlation between in vivo and predicted Kp,uu,brain was the highest using total ER of human MDR1 and BCRP and optimized scaling factors. MDR1 interactors were tested on all MDR1 orthologs using digoxin and quinidine as substrates. We found several examples of inhibition dependent on either substrate or transporter abundance. In summary, this assay system has the potential for early-stage brain penetration screening. IC50 comparison between orthologs is complex; correlation with transporter abundance data is not necessarily proportional and requires the understanding of modes of transporter inhibition.
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Affiliation(s)
- Emőke Sóskuti
- Charles River Laboratories Hungary, H-1117 Budapest, Hungary; (E.S.); (N.S.); (C.T.-A.); (Z.U.); (O.C.)
- Doctoral School of Semmelweis University, Molecular Medicine Division, H-1085 Budapest, Hungary
| | - Nóra Szilvásy
- Charles River Laboratories Hungary, H-1117 Budapest, Hungary; (E.S.); (N.S.); (C.T.-A.); (Z.U.); (O.C.)
| | | | - Zoltán Urbán
- Charles River Laboratories Hungary, H-1117 Budapest, Hungary; (E.S.); (N.S.); (C.T.-A.); (Z.U.); (O.C.)
| | - Olivér Csíkvári
- Charles River Laboratories Hungary, H-1117 Budapest, Hungary; (E.S.); (N.S.); (C.T.-A.); (Z.U.); (O.C.)
| | - Zoltán Szabó
- Department of Medical Chemistry, Albert Szent-Györgyi Medical School, University of Szeged, H-6720 Szeged, Hungary; (Z.S.); (G.K.)
| | - Gábor Kecskeméti
- Department of Medical Chemistry, Albert Szent-Györgyi Medical School, University of Szeged, H-6720 Szeged, Hungary; (Z.S.); (G.K.)
| | - Éva Pusztai
- Department of Chemical and Environmental Process Engineering, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, H-1111 Budapest, Hungary;
| | - Zsuzsanna Gáborik
- Charles River Laboratories Hungary, H-1117 Budapest, Hungary; (E.S.); (N.S.); (C.T.-A.); (Z.U.); (O.C.)
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2
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Loryan I, Reichel A, Feng B, Bundgaard C, Shaffer C, Kalvass C, Bednarczyk D, Morrison D, Lesuisse D, Hoppe E, Terstappen GC, Fischer H, Di L, Colclough N, Summerfield S, Buckley ST, Maurer TS, Fridén M. Unbound Brain-to-Plasma Partition Coefficient, K p,uu,brain-a Game Changing Parameter for CNS Drug Discovery and Development. Pharm Res 2022; 39:1321-1341. [PMID: 35411506 PMCID: PMC9246790 DOI: 10.1007/s11095-022-03246-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 03/22/2022] [Indexed: 12/11/2022]
Abstract
PURPOSE More than 15 years have passed since the first description of the unbound brain-to-plasma partition coefficient (Kp,uu,brain) by Prof. Margareta Hammarlund-Udenaes, which was enabled by advancements in experimental methodologies including cerebral microdialysis. Since then, growing knowledge and data continue to support the notion that the unbound (free) concentration of a drug at the site of action, such as the brain, is the driving force for pharmacological responses. Towards this end, Kp,uu,brain is the key parameter to obtain unbound brain concentrations from unbound plasma concentrations. METHODS To understand the importance and impact of the Kp,uu,brain concept in contemporary drug discovery and development, a survey has been conducted amongst major pharmaceutical companies based in Europe and the USA. Here, we present the results from this survey which consisted of 47 questions addressing: 1) Background information of the companies, 2) Implementation, 3) Application areas, 4) Methodology, 5) Impact and 6) Future perspectives. RESULTS AND CONCLUSIONS From the responses, it is clear that the majority of the companies (93%) has established a common understanding across disciplines of the concept and utility of Kp,uu,brain as compared to other parameters related to brain exposure. Adoption of the Kp,uu,brain concept has been mainly driven by individual scientists advocating its application in the various companies rather than by a top-down approach. Remarkably, 79% of all responders describe the portfolio impact of Kp,uu,brain implementation in their companies as 'game-changing'. Although most companies (74%) consider the current toolbox for Kp,uu,brain assessment and its validation satisfactory for drug discovery and early development, areas of improvement and future research to better understand human brain pharmacokinetics/pharmacodynamics translation have been identified.
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Affiliation(s)
- Irena Loryan
- Department of Pharmacy, Uppsala University, Box 580, Uppsala, Sweden.
| | | | - Bo Feng
- DMPK, Vertex Pharmaceuticals, Boston, Massachusetts, 02210, USA
| | | | - Christopher Shaffer
- External Innovation, Research & Development, Biogen Inc., Cambridge, Massachusetts, USA
| | - Cory Kalvass
- DMPK-BA, AbbVie, Inc., North Chicago, Illinois, USA
| | - Dallas Bednarczyk
- Pharmacokinetic Sciences, Novartis Institutes for BioMedical Research, Cambridge, Massachusetts, USA
| | | | | | - Edmund Hoppe
- DMPK, Boehringer-Ingelheim Pharma GmbH & Co. KG, Biberach, Germany
| | | | - Holger Fischer
- Translational PK/PD and Clinical Pharmacology, Pharmaceutical Sciences, Roche Pharma Research & Early Development, Roche Innovation Center Basel, Basel, Switzerland
| | - Li Di
- Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research and Development, Groton, Connecticut, USA
| | | | - Scott Summerfield
- Bioanalysis Immunogenicity and Biomarkers, GSK, Gunnels Wood Road, Stevenage, SG1 2NY, Hertfordshire, UK
| | | | - Tristan S Maurer
- Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research and Development, Cambridge, Massachusetts, USA
| | - Markus Fridén
- Department of Pharmacy, Uppsala University, Box 580, Uppsala, Sweden
- Inhalation Product Development, Pharmaceutical Technology & Development, Operations, AstraZeneca, Gothenburg, Sweden
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3
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Varrone A, Bundgaard C, Bang-Andersen B. PET as a Translational Tool in Drug Development for Neuroscience Compounds. Clin Pharmacol Ther 2022; 111:774-785. [PMID: 35201613 PMCID: PMC9305164 DOI: 10.1002/cpt.2548] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 01/29/2022] [Indexed: 11/05/2022]
Abstract
In central nervous system drug discovery programs, early development of new chemical entities (NCEs) requires a multidisciplinary strategy and a translational approach to obtain proof of distribution, proof of occupancy, and proof of function in specific brain circuits. Positron emission tomography (PET) provides a way to assess in vivo the brain distribution of NCEs and their binding to the target of interest, provided that radiolabeling of the NCE is possible or that a suitable radioligand is available. PET is therefore a key tool for early phases of drug discovery programs. This review will summarize the main applications of PET in early drug development and discuss the usefulness of PET microdosing studies performed with direct labelling of the NCE and PET occupancy studies. The purpose of this review is also to propose an alignment of the nomenclatures used by drug metabolism and pharmacokinetic scientists and PET imaging scientists to indicate key pharmacokinetic parameters and to provide guidance in the performance and interpretation of PET studies.
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Affiliation(s)
- Andrea Varrone
- Translational Biomarkers and Imaging, H. Lundbeck A/S, Copenhagen, Denmark
| | | | - Benny Bang-Andersen
- Translational Biomarkers and Imaging, H. Lundbeck A/S, Copenhagen, Denmark.,Medicinal Chemistry & Translational DMPK, H. Lundbeck A/S, Copenhagen, Denmark
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4
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Silberbauer LR, Rischka L, Vraka C, Hartmann AM, Godbersen GM, Philippe C, Pacher D, Nics L, Klöbl M, Unterholzner J, Stimpfl T, Wadsak W, Hahn A, Hacker M, Rujescu D, Kasper S, Lanzenberger R, Gryglewski G. ABCB1 variants and sex affect serotonin transporter occupancy in the brain. Mol Psychiatry 2022; 27:4502-4509. [PMID: 36071112 PMCID: PMC7613909 DOI: 10.1038/s41380-022-01733-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 07/20/2022] [Accepted: 07/29/2022] [Indexed: 12/14/2022]
Abstract
Strategies to personalize psychopharmacological treatment promise to improve efficacy and tolerability. We measured serotonin transporter occupancy immediately after infusion of the widely prescribed P-glycoprotein substrate citalopram and assessed to what extent variants of the ABCB1 gene affect drug target engagement in the brain in vivo. A total of 79 participants (39 female) including 31 patients with major depression and 48 healthy volunteers underwent two PET/MRI scans with the tracer [11C]DASB and placebo-controlled infusion of citalopram (8 mg) in a cross-over design. We tested the effect of six ABCB1 single nucleotide polymorphisms and found lower SERT occupancy in ABCB1 rs2235015 minor allele carriers (n = 26, MAF = 0.18) compared to major allele homozygotes (t73 = 2.73, pFWE < 0.05) as well as in men compared to women (t73 = 3.33, pFWE < 0.05). These effects were robust to correction for citalopram plasma concentration, age and diagnosis. From occupancy we derived the ratio of occupied to unoccupied SERT, because in theory this measure is equal to the product of drug affinity and concentration at target sites. A model combining genotype with basic clinical variables, predicted that, at the same dosage, occupied to unoccupied SERT ratio was -14.48 ± 5.38% lower in rs2235015 minor allele carriers, +19.10 ± 6.95% higher in women, -4.83 ± 2.70% lower per 10 kg bodyweight, and -2.68 ± 3.07% lower per 10 years of age. Our results support the exploration of clinical algorithms with adjustment of initial citalopram dosing and highlight the potential of imaging-genetics for precision pharmacotherapy in psychiatry.
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Affiliation(s)
- Leo R. Silberbauer
- grid.22937.3d0000 0000 9259 8492Department of Psychiatry and Psychotherapy, Comprehensive Center for Clinical Neurosciences and Mental Health, Medical University of Vienna, Vienna, Austria
| | - Lucas Rischka
- grid.22937.3d0000 0000 9259 8492Department of Psychiatry and Psychotherapy, Comprehensive Center for Clinical Neurosciences and Mental Health, Medical University of Vienna, Vienna, Austria
| | - Chrysoula Vraka
- grid.22937.3d0000 0000 9259 8492Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria
| | - Annette M. Hartmann
- grid.22937.3d0000 0000 9259 8492Department of Psychiatry and Psychotherapy, Comprehensive Center for Clinical Neurosciences and Mental Health, Medical University of Vienna, Vienna, Austria
| | - Godber Mathis Godbersen
- grid.22937.3d0000 0000 9259 8492Department of Psychiatry and Psychotherapy, Comprehensive Center for Clinical Neurosciences and Mental Health, Medical University of Vienna, Vienna, Austria
| | - Cécile Philippe
- grid.22937.3d0000 0000 9259 8492Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria
| | - Daniel Pacher
- grid.22937.3d0000 0000 9259 8492Department of Psychiatry and Psychotherapy, Comprehensive Center for Clinical Neurosciences and Mental Health, Medical University of Vienna, Vienna, Austria
| | - Lukas Nics
- grid.22937.3d0000 0000 9259 8492Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria
| | - Manfred Klöbl
- grid.22937.3d0000 0000 9259 8492Department of Psychiatry and Psychotherapy, Comprehensive Center for Clinical Neurosciences and Mental Health, Medical University of Vienna, Vienna, Austria
| | - Jakob Unterholzner
- grid.22937.3d0000 0000 9259 8492Department of Psychiatry and Psychotherapy, Comprehensive Center for Clinical Neurosciences and Mental Health, Medical University of Vienna, Vienna, Austria
| | - Thomas Stimpfl
- grid.22937.3d0000 0000 9259 8492Clinical Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria
| | - Wolfgang Wadsak
- grid.22937.3d0000 0000 9259 8492Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria ,grid.499898.dCenter for Biomarker Research in Medicine (CBmed), Graz, Austria
| | - Andreas Hahn
- grid.22937.3d0000 0000 9259 8492Department of Psychiatry and Psychotherapy, Comprehensive Center for Clinical Neurosciences and Mental Health, Medical University of Vienna, Vienna, Austria
| | - Marcus Hacker
- grid.22937.3d0000 0000 9259 8492Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria
| | - Dan Rujescu
- grid.22937.3d0000 0000 9259 8492Department of Psychiatry and Psychotherapy, Comprehensive Center for Clinical Neurosciences and Mental Health, Medical University of Vienna, Vienna, Austria
| | - Siegfried Kasper
- grid.22937.3d0000 0000 9259 8492Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Rupert Lanzenberger
- grid.22937.3d0000 0000 9259 8492Department of Psychiatry and Psychotherapy, Comprehensive Center for Clinical Neurosciences and Mental Health, Medical University of Vienna, Vienna, Austria
| | - Gregor Gryglewski
- Department of Psychiatry and Psychotherapy, Comprehensive Center for Clinical Neurosciences and Mental Health, Medical University of Vienna, Vienna, Austria. .,Child Study Center, Yale University, New Haven, CT, USA.
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5
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Kilbourn MR, Cole EL, Scott PJH. In vitro binding affinity vs. in vivo site occupancy: A PET study of four diastereomers of dihydrotetrabenazine (DTBZ) in monkey brain. Nucl Med Biol 2021; 92:38-42. [PMID: 32122751 DOI: 10.1016/j.nucmedbio.2020.02.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 02/16/2020] [Indexed: 10/25/2022]
Abstract
INTRODUCTION In vivo imaging methods such as Positron Emission Tomography (PET) can be used to examine the relationship between in vitro binding affinity and in vivo occupancy of binding sites in the brain for new drug candidates. In this study, PET imaging in monkey brain was used to evaluate that correlation for a set of four diastereomers of the compound dihydrotetrabenazine (DTBZ), the pharmacologically active metabolite of the drug tetrabenazine. METHODS PET studies of DTBZ diastereomers were completed in a single monkey brain. In vivo occupancies (ED50) were estimated using multiple drug doses and the vesicular monoamine transporter 2 specific radioligand (+)-α-[11C] DTBZ, employing a test-retest sequence of control PET scan, drug administration and a second PET scan completed on a single day. RESULTS DTBZ has three chiral carbon centers and eight possible stereoisomers, and in vivo occupancy of the target site VMAT2 was observed only for the four diastereomers of DTBZ having the 11bR absolute configuration. The estimated in vivo occupancies (ED50 values from 0.023 to >3.15 mg/kg) correlated well (R2 = 0.95) with the in vitro binding affinities (Ki values of 4 to 600 nM for the VMAT2), and an even better correlation (R2 = 0.99) was found for the three isomers with in vitro binding affinities <100 nM. CONCLUSIONS If the physiochemical (MW, log P, pKa) or physiological (metabolism, transport, protein binding) properties of a set of drug stereoisomers are considered similar, the binding affinities determined from in vitro assays may predict the in vivo occupancies of the target binding site in the monkey brain.
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Affiliation(s)
- Michael R Kilbourn
- Department of Radiology, University of Michigan Medical School, Ann Arbor, MI 48105, USA.
| | - Erin L Cole
- Department of Radiology, University of Michigan Medical School, Ann Arbor, MI 48105, USA
| | - Peter J H Scott
- Department of Radiology, University of Michigan Medical School, Ann Arbor, MI 48105, USA
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6
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Badolo L, Thirstrup K, Nielsen SM, Püschl A, Jensen T, Watson S, Bundgaard C. Target-Mediated Brain Tissue Binding for Small Molecule Inhibitors of Heat Shock Protein 90. Pharmaceutics 2020; 12:pharmaceutics12111009. [PMID: 33105895 PMCID: PMC7690585 DOI: 10.3390/pharmaceutics12111009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/28/2020] [Accepted: 10/19/2020] [Indexed: 11/21/2022] Open
Abstract
Drug distribution in the brain is generally associated with an affinity for fatty brain tissues and therefore known to be species- and concentration-independent. We report here the effect of target affinity on brain tissue binding for 10 small molecules designed to inhibit brain heat shock protein 90 (HSP90), a widespread protein whose expression is 1–2% of total cytosolic proteins in eucaryotes. Our results show that increasing the test item concentrations from 0.3 to 100 µM increased the unbound fraction 32-fold for the most potent molecules, with no change for the inactive one (1.1 fold change). Saturation of HSP90 led to normal concentration-independent brain tissue binding. In vivo pharmacokinetics performed in rats showed that the overall volume of distribution of compounds is correlated with their affinity for HSP90. The in vitro binding and in vivo pharmacokinetics (PK) performed in rats showed that small molecule HSP90 inhibitors followed the principle of target-mediated drug disposition. We demonstrate that assessing unbound fractions in brain homogenate was subject to HSP90 target interference; this may challenge the process of linking systemic-free drug concentrations to central nervous system unbound concentrations necessary to establish the proper pharmacokinetics/pharmacodynamics (PK/PD) relation needed for human dose prediction.
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Affiliation(s)
- Lassina Badolo
- Translational DMPK, H. Lundbeck A/S, 2500 Copenhagen-Valby, Denmark;
- Correspondence:
| | | | - Søren Møller Nielsen
- Molecular Screening and Pharmacology, H. Lundbeck A/S, 2500 Copenhagen-Valby, Denmark;
| | - Ask Püschl
- Medicinal Chemistry, H. Lundbeck A/S, 2500 Copenhagen-Valby, Denmark; (A.P.); (T.J.); (S.W.)
| | - Thomas Jensen
- Medicinal Chemistry, H. Lundbeck A/S, 2500 Copenhagen-Valby, Denmark; (A.P.); (T.J.); (S.W.)
| | - Steve Watson
- Medicinal Chemistry, H. Lundbeck A/S, 2500 Copenhagen-Valby, Denmark; (A.P.); (T.J.); (S.W.)
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7
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Progressive Effects of Sildenafil on Visual Processing in Rats. Neuroscience 2020; 441:131-141. [PMID: 32615234 DOI: 10.1016/j.neuroscience.2020.06.033] [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: 02/04/2020] [Revised: 05/26/2020] [Accepted: 06/23/2020] [Indexed: 10/24/2022]
Abstract
Photoreceptors are light-sensitive cells in the retina converting visual stimuli into electrochemical signals. These signals are evaluated and interpreted in the visual pathway, a process referred to as visual processing. Phosphodiesterase type 5 and 6 (PDE5 and 6) are abundant enzymes in retinal vessels and notably photoreceptors where PDE6 is exclusively present. The effects of the PDE inhibitor sildenafil on the visual system, have been studied using electroretinography and a variety of clinical visual tasks. Here we evaluate effects of sildenafil administration by electrophysiological recordings of flash visual evoked potentials (VEPs) and steady-state visual evoked potentials (SSVEPs) from key regions in the rodent visual pathway. Progressive changes were investigated in female Sprague-Dawley rats at 10 timepoints from 30 min to 28 h after peroral administration of sildenafil (50 mg/kg). Sildenafil caused a significant reduction in the amplitude of VEPs in both visual cortex and superior colliculus, and a significant delay of the VEPs as demonstrated by increased latency of several VEP peaks. Also, sildenafil-treatment significantly reduced the signal-to-noise ratio of SSVEPs. The effects of sildenafil were dependent on the wavelength condition in both assays. Our results support the observation that while PDE6 is a key player in phototransduction, near full inhibition of PDE6 is not enough to abolish the complex process of visual processing. Taken together, VEPs and SSVEPs are effective in demonstrating progressive effects of drug-induced changes in visual processing in rats and as the same paradigms may be applied in humans, representing a promising tool for translational research.
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8
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Behavioral, Electrophysiological, and Histological Characterization of a New Rat Model for Neoadjuvant Chemotherapy–Induced Neuropathic Pain: Therapeutic Potential of Duloxetine and Allopregnanolone Concomitant Treatment. Neurotox Res 2020; 38:145-162. [DOI: 10.1007/s12640-020-00176-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 01/12/2020] [Accepted: 02/06/2020] [Indexed: 12/13/2022]
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9
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Bhyrapuneni G, Thentu JB, Palacharla VRC, Muddana N, Aleti RR, Ajjala DR, Nirogi R. A definite measure of occupancy exposures, seeking with non-radiolabeled in vivo 5-HT2A receptor occupancy and in vitro free fractions. J Recept Signal Transduct Res 2018; 38:359-366. [PMID: 30481094 DOI: 10.1080/10799893.2018.1531888] [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: 10/27/2022]
Abstract
Unbound drug concentration in the brain would be the true exposure responsible for specific target occupancy. Drug exposures from preclinical are total concentrations of those over/underestimate the clinical dose projection. With the application of mass spectrometry, the current work proposes a definite measure of test drug exposures at serotonin-2A occupancy. The 5-HT2A occupancy of antagonist in the rat brain has determined with non-radiolabeled tracer MDL-100,907 at an optimized dose (3 µg/kg) and treatment time (30 min). Equilibrium dialysis method determines the in vitro free fraction of the test antagonist in untreated rat brain homogenates and plasma. Drug-free fractions derived the unbound concentration (EC50) in plasma and brain at test doses. The corresponding binding affinities (Ki) correlated with the unbound concentrations. Except for quetiapine, the ED50 values in the dose-occupancy curves of antagonists are close and ranged from 1 to 3 mg/kg. The test drug quetiapine, eplivanserin, and clozapine showed high free fractions in plasma, but for ketanserin and olanzapine, the brain free fraction was higher. The correlation between the unbound EC50 of the antagonists and corresponding Ki values was good (r2=0.828). The improved EC50 accuracy with unbound concentrations was 10-250 folds in plasma and 10-170 folds in the brain. Further, the free fractions (fu, plasma/fu, brain) of test drugs had shown a correlation of ∼83% with brain permeability (Ctotal brain/Ctotal plasma), a limiting factor. Thus, correlating the occupancy with unbound exposure and pharmacology would result in an accurate measurement of drug potency and optimizes in selecting the clinical dose.
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10
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Liu H, Dong K, Zhang W, Summerfield SG, Terstappen GC. Prediction of brain:blood unbound concentration ratios in CNS drug discovery employing in silico and in vitro model systems. Drug Discov Today 2018; 23:1357-1372. [PMID: 29548981 DOI: 10.1016/j.drudis.2018.03.002] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 02/03/2018] [Accepted: 03/08/2018] [Indexed: 12/15/2022]
Abstract
Recent years have seen a paradigm shift away from optimizing the brain:blood concentration ratio toward the more relevant brain:blood unbound concentration ratio (Kp,uu,br) in CNS drug discovery. Here, we review the recent developments in the in silico and in vitro model systems to predict the Kp,uu,br of discovery compounds with special emphasis on the in-vitro-in-vivo correlation. We also discuss clinical 'translation' of rodent Kp,uu,br and highlight the future directions for improvement in brain penetration prediction. Important in this regard are in silico Kp,uu,br models built on larger datasets of high quality, calibration and deeper understanding of experimental in vitro transporter systems, and better understanding of blood-brain barrier transporters and their in vivo relevance aside from P-gp and BCRP.
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Affiliation(s)
- Houfu Liu
- Platform Technology and Science, GlaxoSmithKline R&D Center, Shanghai, China.
| | - Kelly Dong
- Platform Technology and Science, GlaxoSmithKline R&D Center, Shanghai, China
| | - Wandong Zhang
- Platform Technology and Science, GlaxoSmithKline R&D Center, Shanghai, China
| | - Scott G Summerfield
- Bioanalysis, Immunogenicity and Biomarker, Platform Technology and Science, GlaxoSmithKline, Ware, UK
| | - Georg C Terstappen
- Platform Technology and Science, GlaxoSmithKline R&D Center, Shanghai, China
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11
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PFE-360-induced LRRK2 inhibition induces reversible, non-adverse renal changes in rats. Toxicology 2018; 395:15-22. [DOI: 10.1016/j.tox.2018.01.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 12/22/2017] [Accepted: 01/03/2018] [Indexed: 11/21/2022]
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12
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Bétry C, Overstreet D, Haddjeri N, Pehrson A, Bundgaard C, Sanchez C, Mørk A. A 5-HT3 receptor antagonist potentiates the behavioral, neurochemical and electrophysiological actions of an SSRI antidepressant. Pharmacol Biochem Behav 2015; 131:136-42. [DOI: 10.1016/j.pbb.2015.02.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 02/07/2015] [Accepted: 02/10/2015] [Indexed: 12/29/2022]
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13
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Mechanistic Understanding of Brain Drug Disposition to Optimize the Selection of Potential Neurotherapeutics in Drug Discovery. Pharm Res 2014; 31:2203-19. [DOI: 10.1007/s11095-014-1319-1] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 01/28/2014] [Indexed: 01/09/2023]
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14
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LC–MS/MS method for the quantification of almotriptan in dialysates: Application to rat brain and blood microdialysis study. J Pharm Biomed Anal 2013; 81-82:160-7. [DOI: 10.1016/j.jpba.2013.04.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 04/05/2013] [Accepted: 04/09/2013] [Indexed: 11/15/2022]
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15
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de Lange ECM. Utility of CSF in translational neuroscience. J Pharmacokinet Pharmacodyn 2013; 40:315-26. [PMID: 23400635 PMCID: PMC3663203 DOI: 10.1007/s10928-013-9301-9] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Accepted: 01/30/2013] [Indexed: 01/19/2023]
Abstract
Human cerebrospinal fluid (CSF) sampling is of high value as the only general applicable methodology to obtain information on free drug concentrations in individual human brain. As the ultimate interest is in the free drug concentration at the CNS target site, the question is what CSF concentrations may tell us in that respect. Studies have been performed in rats and other animals for which concentrations in brain extracellular fluid (brain ECF) as a target site for many drugs, have been compared to (cisterna magna) CSF concentrations, at presumed steady state conditions,. The data indicated that CSF drug concentrations provided a rather good indication of, but not a reliable measure for predicting brain ECF concentrations. Furthermore, comparing rat with human CSF concentrations, human CSF concentrations tend to be higher and display much more variability. However, this comparison of CSF concentrations cannot be a direct one, as humans probably had a disease for which CSF was collected in the first place, while the rats were healthy. In order to be able to more accurately predict human brain ECF concentrations, understanding of the complexity of the CNS in terms of intrabrain pharmacokinetic relationships and the influence of CNS disorders on brain pharmacokinetics needs to be increased. This can be achieved by expanding a currently existing preclinically derived physiologically based pharmacokinetic model for brain distribution. This model has been shown to successfully predict data obtained for human lumbar CSF concentrations of acetaminophen which renders trust in the model prediction of human brain ECF concentrations. This model should further evolute by inclusion of influences of drug properties, fluid flows, transporter functionalities and different disease conditions. Finally the model should include measures of target site engagement and CNS effects, to ultimately learn about concentrations that best predict particular target site concentrations, via human CSF concentrations.
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Nirogi R, Kandikere V, Bhyrapuneni G, Benade V, Saralaya R, Irappanavar S, Muddana N, Ajjala DR. Approach to reduce the non-specific binding in microdialysis. J Neurosci Methods 2012; 209:379-87. [DOI: 10.1016/j.jneumeth.2012.06.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 05/30/2012] [Accepted: 06/13/2012] [Indexed: 11/24/2022]
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