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Pang KS, Lu WI, Mulder GJ. After 50 Years of Hepatic Clearance Models, Where Should We Go from Here? Improvements and Implications for Physiologically Based Pharmacokinetic Modeling. Drug Metab Dispos 2024; 52:919-931. [PMID: 39013583 DOI: 10.1124/dmd.124.001649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 04/25/2024] [Indexed: 07/18/2024] Open
Abstract
There is overwhelming preference for application of the unphysiologic, well-stirred model (WSM) over the parallel tube model (PTM) and dispersion model (DM) to predict hepatic drug clearance, CLH , despite that liver blood flow is dispersive and closer to the DM in nature. The reasoning is the ease in computation relating the hepatic intrinsic clearance ( CLint ), hepatic blood flow ( QH ), unbound fraction in blood ( fub ) and the transmembrane clearances ( CLin and CLef ) to CLH for the WSM. However, the WSM, being the least efficient liver model, predicts a lower EH that is associated with the in vitro CLint ( Vmax / Km ), therefore requiring scale-up to predict CLH in vivo. By contrast, the miniPTM, a three-subcompartment tank-in-series model of uniform enzymes, closely mimics the DM and yielded similar patterns for CLint versus EH , substrate concentration [S] , and KL / B , the tissue to outflow blood concentration ratio. We placed these liver models nested within physiologically based pharmacokinetic models to describe the kinetics of the flow-limited, phenolic substrate, harmol, using the WSM (single compartment) and the miniPTM and zonal liver models (ZLMs) of evenly and unevenly distributed glucuronidation and sulfation activities, respectively, to predict CLH For the same, given CLint ( Vmax and Km ), the WSM again furnished the lowest extraction ratio ( EH,WSM = 0.5) compared with the miniPTM and ZLM (>0.68). Values of EH,WSM were elevated to those for EH, PTM and EH, ZLM when the Vmax s for sulfation and glucuronidation were raised 5.7- to 1.15-fold. The miniPTM is easily manageable mathematically and should be the new normal for liver/physiologic modeling. SIGNIFICANCE STATEMENT: Selection of the proper liver clearance model impacts strongly on CLH predictions. The authors recommend use of the tank-in-series miniPTM (3 compartments mini-parallel tube model), which displays similar properties as the dispersion model (DM) in relating CLint and [ S ] to CLH as a stand-in for the DM, which best describes the liver microcirculation. The miniPTM is readily modified to accommodate enzyme and transporter zonation.
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Affiliation(s)
- K Sandy Pang
- Leslie Dan Faculty of Pharmacy, University of Toronto, Ontario, Canada (K.S.P., W.I.L.) and Department of Toxicology, Leiden Academic Centre for Drug Research, Leiden University, The Netherlands (G.J.M.)
| | - Weijia Ivy Lu
- Leslie Dan Faculty of Pharmacy, University of Toronto, Ontario, Canada (K.S.P., W.I.L.) and Department of Toxicology, Leiden Academic Centre for Drug Research, Leiden University, The Netherlands (G.J.M.)
| | - Gerard J Mulder
- Leslie Dan Faculty of Pharmacy, University of Toronto, Ontario, Canada (K.S.P., W.I.L.) and Department of Toxicology, Leiden Academic Centre for Drug Research, Leiden University, The Netherlands (G.J.M.)
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Wang P, Wang WJ, Choi-Nurvitadhi J, Lescaille Y, Murray JW, Wolkoff AW. Rat Organic Anion Transport Protein 1A1 Interacts Directly With Organic Anion Transport Protein 1A4 Facilitating Its Maturation and Trafficking to the Hepatocyte Plasma Membrane. Hepatology 2019; 70:2156-2170. [PMID: 31102415 PMCID: PMC6859187 DOI: 10.1002/hep.30772] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 05/12/2019] [Indexed: 12/16/2022]
Abstract
Organic anion transport proteins (OATPs) on the basolateral surface of hepatocytes mediate uptake of a number of drugs and endogenous compounds. Previous studies showed that rat OATP1A1 (rOATP1A1) has a postsynaptic density protein, drosophila disc large tumor suppressor, zonula occludens-1 protein (PDZ) consensus binding motif at its C-terminus and binds to PDZ domain containing 1 (PDZK1), which is required for its cell-surface localization. PDZK1 associates with rOATP1A1-containing endocytic vesicles within cells, mediating recruitment of motor proteins required for microtubule-based trafficking to the plasma membrane. rOATP1A4 also traffics to the plasma membrane, although it lacks a PDZ binding consensus sequence. The current study was designed to test the hypothesis that trafficking of rOATP1A4 to the plasma membrane requires its direct interaction with rOATP1A1 resulting in a complex that traffics through the cell in common subcellular vesicles in which the cytosolic tail of rOATP1A1 is bound to PDZK1. We found that 74% of rOATP1A4-containing rat liver endocytic vesicles (n = 12,044) also contained rOATP1A1. Studies in transfected HEK293 cells showed surface localization of rOATP1A1 only when coexpressed with PDZK1 whereas rOATP1A4 required coexpression with rOATP1A1 and PDZK1. Studies in stably transfected HeLa cells that constitutively expressed PDZK1 showed that coexpression of rOATP1A4 with rOATP1A1 resulted in more rapid appearance of rOATP1A4 on the plasma membrane and faster maturation to its fully glycosylated form. Similar results were observed on immunofluorescence analysis of single cells. Immunoprecipitation of rat liver or transfected HeLa cell lysates with rOATP1A1 antibody specifically co-immunoprecipitated rOATP1A4 as determined by western blotting. Conclusion: These studies indicate that optimal rOATP1A4 trafficking to the cell surface is dependent upon coexpression and interaction with rOATP1A1. As rOATP1A1 binds to the chaperone protein, PDZK1, rOATP1A4 functionally hitchhikes through the cell with this complex.
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Affiliation(s)
- Pijun Wang
- Marion Bessin Liver Research Center, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York 10461, USA
| | - Wen-Jun Wang
- Marion Bessin Liver Research Center, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York 10461, USA,Department of Anatomy and Structural Biology, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York 10461, USA
| | - Jo Choi-Nurvitadhi
- Marion Bessin Liver Research Center, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York 10461, USA,Department of Anatomy and Structural Biology, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York 10461, USA
| | - Yaniuska Lescaille
- Marion Bessin Liver Research Center, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York 10461, USA,Division of Hepatology, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York 10461, USA
| | - John W. Murray
- Marion Bessin Liver Research Center, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York 10461, USA,Department of Anatomy and Structural Biology, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York 10461, USA
| | - Allan W. Wolkoff
- Marion Bessin Liver Research Center, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York 10461, USA,Department of Anatomy and Structural Biology, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York 10461, USA,Division of Hepatology, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York 10461, USA
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Polak S, Tylutki Z, Holbrook M, Wiśniowska B. Better prediction of the local concentration-effect relationship: the role of physiologically based pharmacokinetics and quantitative systems pharmacology and toxicology in the evolution of model-informed drug discovery and development. Drug Discov Today 2019; 24:1344-1354. [PMID: 31132414 DOI: 10.1016/j.drudis.2019.05.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 03/04/2019] [Accepted: 05/21/2019] [Indexed: 12/15/2022]
Abstract
Model-informed drug discovery and development (MID3) is an umbrella term under which sit several computational approaches: quantitative systems pharmacology (QSP), quantitative systems toxicology (QST) and physiologically based pharmacokinetics (PBPK). QSP models are built using mechanistic knowledge of the pharmacological pathway focusing on the putative mechanism of drug efficacy; whereas QST models focus on safety and toxicity issues and the molecular pathways and networks that drive these adverse effects. These can be mediated through exaggerated on-target or off-target pharmacology, immunogenicity or the physiochemical nature of the compound. PBPK models provide a mechanistic description of individual organs and tissues to allow the prediction of the intra- and extra-cellular concentration of the parent drug and metabolites under different conditions. Information on biophase concentration enables the prediction of a drug effect in different organs and assessment of the potential for drug-drug interactions. Together, these modelling approaches can inform the exposure-response relationship and hence support hypothesis generation and testing, compound selection, hazard identification and risk assessment through to clinical proof of concept (POC) and beyond to the market.
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Affiliation(s)
- Sebastian Polak
- Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9 Street, 30-688 Kraków, Poland; Certara-Simcyp, Level 2-Acero, 1 Concourse Way, Sheffield, S1 2BJ, UK.
| | - Zofia Tylutki
- Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9 Street, 30-688 Kraków, Poland; Certara-Simcyp, Level 2-Acero, 1 Concourse Way, Sheffield, S1 2BJ, UK
| | - Mark Holbrook
- Certara-Simcyp, Level 2-Acero, 1 Concourse Way, Sheffield, S1 2BJ, UK
| | - Barbara Wiśniowska
- Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9 Street, 30-688 Kraków, Poland
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Abstract
Many of the compounds taken up by the liver are organic anions that circulate tightly bound to protein carriers such as albumin. The fenestrated sinusoidal endothelium of the liver permits these compounds to have access to hepatocytes. Studies to characterize hepatic uptake of organic anions through kinetic analyses, suggested that it was carrier-mediated. Attempts to identify specific transporters by biochemical approaches were largely unsuccessful and were replaced by studies that utilized expression cloning. These studies led to identification of the organic anion transport proteins (oatps), a family of 12 transmembrane domain glycoproteins that have broad and often overlapping substrate specificities. The oatps mediate Na(+)-independent organic anion uptake. Other studies identified a seven transmembrane domain glycoprotein, Na(+)/taurocholate transporting protein (ntcp) as mediating Na(+)-dependent uptake of bile acids as well as other organic anions. Although mutations or deficiencies of specific members of the oatp family have been associated with transport abnormalities, there have been no such reports for ntcp, and its physiologic role remains to be determined, although expression of ntcp in vitro recapitulates the characteristics of Na(+)-dependent bile acid transport that is seen in vivo. Both ntcp and oatps traffic between the cell surface and intracellular vesicular pools. These vesicles move through the cell on microtubules, using the microtubule based motors dynein and kinesins. Factors that regulate this motility are under study and may provide a unique mechanism that can alter the plasma membrane content of these transporters and consequently their accessibility to circulating ligands.
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Affiliation(s)
- Allan W Wolkoff
- The Herman Lopata Chair in Liver Disease Research, Professor of Medicine and Anatomy and Structural Biology, Associate Chair of Medicine for Research, Chief, Division of Gastroenterology and Liver Diseases, Director, Marion Bessin Liver Research Center, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, NY
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5
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Yang QJ, Si L, Tang H, Sveigaard HH, Chow ECY, Pang KS. PBPK Modeling to Unravel Nonlinear Pharmacokinetics of Verapamil to Estimate the Fractional Clearance for Verapamil N-Demethylation in the Recirculating Rat Liver Preparation. Drug Metab Dispos 2015; 43:631-45. [DOI: 10.1124/dmd.114.062265] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
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Vitamin D receptor activation induces P-glycoprotein and increases brain efflux of quinidine: an intracerebral microdialysis study in conscious rats. Pharm Res 2014; 32:1128-40. [PMID: 25319098 DOI: 10.1007/s11095-014-1524-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 09/12/2014] [Indexed: 01/20/2023]
Abstract
PURPOSE Since the vitamin D receptor (VDR) was found to up-regulate cerebral P-glycoprotein expression in vitro and in mice, we extend our findings to rats by assessing the effect of rat Vdr activation on brain efflux of quinidine, a P-gp substrate that is eliminated primarily by cytochrome P450 3a. METHODS We treated rats with vehicle or the active VDR ligand, 1α,25-dihydroxyvitamin D3 [1,25(OH)2D3] (4.8 or 6.4 nmol/kg i.p. every 2nd day × 4) and examined P-gp expression and cerebral quinidine disposition via microdialysis in control and treatment studies conducted longitudinally in the same rat. RESULTS The 6.4 nmol/kg 1,25(OH)2D3 dose increased cerebral P-gp expression 1.75-fold whereas hepatic Cyp3a remained unchanged. Although there was no change in systemic clearance elicited by 1,25(OH)2D3, brain extracellular fluid quinidine concentrations were lower in treated rats. We noted that insertion of indwelling catheters increased plasma protein binding of quinidine and serial sampling decreased the blood:plasma concentration ratio, factors that alter distribution ratios in microdialysis studies. After appropriate correction, KECF/P,uu and KECF/B,uu, or ratios of quinidine unbound concentrations in brain extracellular fluid to plasma or blood at steady-state, were more than halved. CONCLUSION We demonstrate that VDR activation increases cerebral P-gp expression and delimits brain penetration of P-gp substrates.
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Tissue-to-blood distribution coefficients in the rat: Utility for estimation of the volume of distribution in man. Eur J Pharm Sci 2013; 50:526-43. [DOI: 10.1016/j.ejps.2013.08.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 07/03/2013] [Accepted: 08/13/2013] [Indexed: 12/21/2022]
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8
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Cho HJ, Kim JE, Kim DD, Yoon IS. In vitro–in vivoextrapolation (IVIVE) for predicting human intestinal absorption and first-pass elimination of drugs: principles and applications. Drug Dev Ind Pharm 2013; 40:989-98. [DOI: 10.3109/03639045.2013.831439] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Li P, Weiss M, Roberts MS. Hepatic interaction between quinidine and digoxin: role of inhibition of sinusoidal Na⁺/K⁺ ATPase digoxin binding. Eur J Pharm Sci 2012; 47:506-11. [PMID: 22820029 DOI: 10.1016/j.ejps.2012.07.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Revised: 06/04/2012] [Accepted: 07/08/2012] [Indexed: 12/13/2022]
Abstract
The mechanism by which quinidine affects hepatic digoxin pharmacokinetics remains controversial. Here, we study the role of displacement of digoxin from hepatic sinusoidal binding sites by quinidine. We used the impulse-response technique in the single-pass perfused rat liver to describe the digoxin hepatic disposition by a physiologically-based pharmacokinetic liver model. The impulse-response study involved analysis of outflow curves following two consecutive doses of digoxin (42 and 125 μg) without and with quinidine (10 μM) in perfusate. In addition, the effect of quinidine on digoxin binding in liver subcellular fractions was quantified. Quinidine increased the peak outflow concentration for digoxin at the low digoxin dose but not at the high dose. This increase could be adequately described when digoxin displacement from sinusoidal and intrahepatic binding sites was included in the model. Inhibition of digoxin binding by quinidine was also observed in vitro. The decrease of biliary excretion of digoxin by quinidine was accompanied by a linear increase in sinusoidal efflux of digoxin's primary metabolite, digoxigenin bisdigitoxoside (Dg2). In contrast to biliary excretion, inhibition of sinusoidal uptake may become dominant only for high concentrations of quinidine.
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Affiliation(s)
- Peng Li
- Therapeutics Research Centre, School of Medicine, The University of Queensland, Princess Alexandra Hospital, Woolloongabba, QLD 4102, Australia
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10
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Kotani N, Maeda K, Watanabe T, Hiramatsu M, Gong LK, Bi YA, Takezawa T, Kusuhara H, Sugiyama Y. Culture Period-Dependent Changes in the Uptake of Transporter Substrates in Sandwich-Cultured Rat and Human Hepatocytes. Drug Metab Dispos 2011; 39:1503-10. [DOI: 10.1124/dmd.111.038968] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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11
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Kimoto E, Chupka J, Xiao Y, Bi YA, Duignan DB. Characterization of Digoxin Uptake in Sandwich-Cultured Human Hepatocytes. Drug Metab Dispos 2010; 39:47-53. [DOI: 10.1124/dmd.110.034298] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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12
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Weiss M, Li P, Roberts MS. An improved nonlinear model describing the hepatic pharmacokinetics of digoxin: evidence for two functionally different uptake systems and saturable binding. Pharm Res 2010; 27:1999-2007. [PMID: 20625800 DOI: 10.1007/s11095-010-0204-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2010] [Accepted: 06/22/2010] [Indexed: 11/26/2022]
Abstract
PURPOSE To develop a semi-distributed liver model for the evaluation of saturable sinusoidal uptake and binding kinetics of the Oatp1a4 substrate digoxin. METHODS In the perfused rat liver, two successive digoxin doses of 42 and 125 microg were administered, and the outflow concentration was determined by LC/MS/MS. [14C]-sucrose was used as vascular reference. The data were analyzed simultaneously by a population approach using sucrose to determine the sinusoidal mixing of digoxin. RESULTS The results suggest the existence of a high-affinity, low-capacity system, and a low-affinity, high-capacity system for sinusoidal uptake with apparent Michaelis constants (K(M)) of 0.24 and 332 microg/ml, respectively. Incorporation of saturable sinusoidal binding of digoxin considerably improved the fit, and the parameter estimates were consistent with those of binding to hepatic Na,K-ATPase. Simpler models that neglect the concentration gradient in flow direction failed to describe the outflow data in the high dose range. CONCLUSION The semi-distributed liver model with saturable uptake should be useful for a functional characterization of transporters in the in situ rat liver.
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Affiliation(s)
- Michael Weiss
- Section of Pharmacokinetics, Department of Pharmacology, Martin Luther University Halle-Wittenberg, 06097 Halle, Germany.
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Pang KS, Morris ME, Sun H. Formed and preformed metabolites: facts and comparisons. J Pharm Pharmacol 2010; 60:1247-75. [DOI: 10.1211/jpp.60.10.0001] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Abstract
The administration of metabolites arising from new drug entities is often employed in drug discovery to investigate their associated toxicity. It is expected that administration of metabolites can predict the exposure of metabolites originating from the administration of precursor drug. Whether exact and meaningful information can be obtained from this has been a topic of debate. This communication summarizes observations and theoretical relationships based on physiological modelling for the liver, kidney and intestine, three major eliminating organs/tissues. Theoretical solutions based on physiological modelling of organs were solved, and the results suggest that deviations are expected. Here, examples of metabolite kinetics observed mostly in perfused organs that did not match predictions are provided. For the liver, discrepancies in fate between formed and preformed metabolites may be explained by the heterogeneity of enzymes, the presence of membrane barriers and whether transporters are involved. For the kidney, differences have been attributed to glomerular filtration of the preformed but not the formed metabolite. For the intestine, the complexity of segregated flows to the enterocyte and serosal layers and differences in metabolism due to the route of administration are addressed. Administration of the metabolite may or may not directly reflect the toxicity associated with drug use. However, kinetic data on the preformed metabolite will be extremely useful to develop a sound model for modelling and simulations; in-vitro evidence on metabolite handling at the target organ is also paramount. Subsequent modelling and simulation of metabolite data arising from a combined model based on both drug and preformed metabolite data are needed to improve predictions on the behaviours of formed metabolites.
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Affiliation(s)
- K Sandy Pang
- Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Toronto, Ontario, M5S 3M2, Canada
| | - Marilyn E Morris
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, State University of New York, Amherst, NY 14260, USA
| | - Huadong Sun
- Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Toronto, Ontario, M5S 3M2, Canada
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Dash A, Inman W, Hoffmaster K, Sevidal S, Kelly J, Obach RS, Griffith LG, Tannenbaum SR. Liver tissue engineering in the evaluation of drug safety. Expert Opin Drug Metab Toxicol 2009; 5:1159-74. [PMID: 19637986 PMCID: PMC4110978 DOI: 10.1517/17425250903160664] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Assessment of drug-liver interactions is an integral part of predicting the safety profile of new drugs. Existing model systems range from in vitro cell culture models to FDA-mandated animal tests. Data from these models often fail, however, to predict human liver toxicity, resulting in costly failures of clinical trials. In vitro screens based on cultured hepatocytes are now commonly used in early stages of development, but many toxic responses in vivo seem to be mediated by a complex interplay among several different cell types. We discuss some of the evolving trends in liver cell culture systems applied to drug safety assessment and describe an experimental model that captures complex liver physiology through incorporation of heterotypic cell-cell interactions, 3D architecture and perfused flow. We demonstrate how heterotypic interactions in this system can be manipulated to recreate an inflammatory environment and apply the model to test compounds that potentially exhibit idiosyncratic drug toxicity. Finally, we provide a perspective on how the range of existing and emerging in vitro liver culture approaches, from simple to complex, might serve needs across the range of stages in drug discovery and development, including applications in molecular therapeutics.
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Affiliation(s)
- Ajit Dash
- Underwood-Prescott Professor of Toxicology and Chemistry, Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Office 56-731A, Cambridge, MA 02139, USA
| | - Walker Inman
- Underwood-Prescott Professor of Toxicology and Chemistry, Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Office 56-731A, Cambridge, MA 02139, USA
| | - Keith Hoffmaster
- Novartis Institute of Biomedical Research, 350 Massachusetts Avenue, Cambridge, Massachusetts, MA 02139, USA
| | - Samantha Sevidal
- Pfizer Research Technology Center, Cambridge, Massachusetts, MA 02139, USA
| | - Joan Kelly
- Pfizer Research Technology Center, Cambridge, Massachusetts, MA 02139, USA
| | - R Scott Obach
- Pfizer Research Technology Center, Cambridge, Massachusetts, MA 02139, USA
| | - Linda G Griffith
- Underwood-Prescott Professor of Toxicology and Chemistry, Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Office 56-731A, Cambridge, MA 02139, USA
| | - Steven R Tannenbaum
- Underwood-Prescott Professor of Toxicology and Chemistry, Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Office 56-731A, Cambridge, MA 02139, USA
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Weiss M, Hung DY, Poenicke K, Roberts MS. Kinetic analysis of saturable hepatic uptake of digoxin and its inhibition by rifampicin. Eur J Pharm Sci 2008; 34:345-50. [DOI: 10.1016/j.ejps.2008.05.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2008] [Revised: 04/14/2008] [Accepted: 05/22/2008] [Indexed: 11/29/2022]
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Wolf KK, Brouwer KR, Pollack GM, Brouwer KLR. Effect of albumin on the biliary clearance of compounds in sandwich-cultured rat hepatocytes. Drug Metab Dispos 2008; 36:2086-92. [PMID: 18653747 DOI: 10.1124/dmd.108.020842] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
The purpose of the present study was to evaluate the effects of bovine serum albumin (BSA) and essentially fatty acid-free BSA (BSA-FAF) on the biliary clearance of compounds in sandwich-cultured rat hepatocytes. Unbound fraction, biliary excretion index (BEI), and unbound intrinsic biliary clearance (intrinsic Clbiliary') were determined for digoxin, pravastatin, and taurocholate in the absence or presence of BSA or BSA-FAF. BSA had little effect on the BEI or intrinsic Clbiliary' of these compounds. Surprisingly, BSA-FAF decreased both BEI and intrinsic Clbiliary' for digoxin and pravastatin, which represent low and moderately bound compounds, respectively. The BEI and intrinsic Clbiliary' of taurocholate, a highly bound compound, were not altered significantly by BSA-FAF. Neither BSA nor BSA-FAF had a discernable effect on the bile canalicular networks based on carboxydichlorofluorescein retention. Neither the addition of physiological concentrations of calcium nor the addition of fatty acids to BSA-FAF was able to restore the BEI or intrinsic Clbiliary' of the model compounds to similar values in the absence or presence of BSA. Careful consideration is warranted when selecting the type of BSA for addition to in vitro systems such as sandwich-cultured rat hepatocytes.
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Affiliation(s)
- Kristina K Wolf
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, CB #7360, Kerr Hall Room 3205, Chapel Hill, NC 27599, USA
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Pang KS, Weiss M, Macheras P. Advanced pharmacokinetic models based on organ clearance, circulatory, and fractal concepts. AAPS J 2007; 9:E268-83. [PMID: 17907768 PMCID: PMC2751417 DOI: 10.1208/aapsj0902030] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2007] [Accepted: 05/14/2007] [Indexed: 12/22/2022] Open
Abstract
Three advanced models of pharmacokinetics are described. In the first class are physiologically based pharmacokinetic models based on in vitro data on transport and metabolism. The information is translated as transporter and enzyme activities and their attendant heterogeneities into liver and intestine models. Second are circulatory models based on transit time distribution and plasma concentration time curves. The third are fractal models for nonhomogeneous systems and non-Fickian processes are presented. The usefulness of these pharmacokinetic models, with examples, is compared.
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Affiliation(s)
- K Sandy Pang
- Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Toronto, Ontario, Canada M5S 3M2.
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Liu J, Zeng F, Allen C. In vivo fate of unimers and micelles of a poly(ethylene glycol)-block-poly(caprolactone) copolymer in mice following intravenous administration. Eur J Pharm Biopharm 2007; 65:309-19. [PMID: 17257817 DOI: 10.1016/j.ejpb.2006.11.010] [Citation(s) in RCA: 154] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2006] [Revised: 10/31/2006] [Accepted: 11/01/2006] [Indexed: 11/26/2022]
Abstract
Methoxy poly(ethylene glycol)-b-poly(caprolactone) (MePEG-b-PCL) copolymers with varying PEG block lengths and a constant PCL block length were synthesized by cationic ring-opening polymerization and used to form nano-sized micelles. Due to their small size and superior in vitro stability, the MePEG(5000)-b-PCL(5000) micelles were selected for further in vitro characterization and an in vivo evaluation of their fate and stability following intravenous (i.v.) administration. Specifically, (3)H-labelled MePEG(5000)-b-PCL(5000) micelles were i.v. administered to Balb/C mice at copolymer doses of 250, 2 and 0.2 mg/kg in order to examine the distribution kinetics of (1) copolymer assembled as thermodynamically stable micelles, (2) copolymer assembled as thermodynamically unstable micelles and (3) copolymer unimers, respectively. Overall, it was found that when the copolymer is assembled as thermodynamically stable micelles the material is effectively restricted to the plasma compartment. Interestingly, the copolymer was found to have a relatively long circulation half-life even when administered at a dose that would likely fall to concentrations below the CMC following distribution. Analysis of plasma samples from this group revealed that even 24 h post-administration a significant portion of the copolymer remained assembled as intact micelles. In this way, this study demonstrates that the hydrophobic and semi-crystalline nature of the PCL core imparts a high degree of kinetic stability to this micelle system.
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Affiliation(s)
- Jubo Liu
- Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ont., Canada
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Prueksaritanont T, Lin JH, Baillie TA. Complicating factors in safety testing of drug metabolites: Kinetic differences between generated and preformed metabolites. Toxicol Appl Pharmacol 2006; 217:143-52. [PMID: 17055014 DOI: 10.1016/j.taap.2006.08.009] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2006] [Revised: 08/25/2006] [Accepted: 08/29/2006] [Indexed: 12/15/2022]
Abstract
This paper aims to provide a scientifically based perspective on issues surrounding the proposed toxicology testing of synthetic drug metabolites as a means of ensuring adequate nonclinical safety evaluation of drug candidates that generate metabolites considered either to be unique to humans or are present at much higher levels in humans than in preclinical species. We put forward a number of theoretical considerations and present several specific examples where the kinetic behavior of a preformed metabolite given to animals or humans differs from that of the corresponding metabolite generated endogenously from its parent. The potential ramifications of this phenomenon are that the results of toxicity testing of the preformed metabolite may be misleading and fail to characterize the true toxicological contribution of the metabolite when formed from the parent. It is anticipated that such complications would be evident in situations where (a) differences exist in the accumulation of the preformed versus generated metabolites in specific tissues, and (b) the metabolite undergoes sequential metabolism to a downstream product that is toxic, leading to differences in tissue-specific toxicity. Owing to the complex nature of this subject, there is a need to treat drug metabolite issues in safety assessment on a case-by-case basis, in which a knowledge of metabolite kinetics is employed to validate experimental paradigms that entail administration of preformed metabolites to animal models.
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Liu L, Pang KS. An integrated approach to model hepatic drug clearance. Eur J Pharm Sci 2006; 29:215-30. [PMID: 16806855 DOI: 10.1016/j.ejps.2006.05.007] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2006] [Accepted: 05/16/2006] [Indexed: 11/15/2022]
Abstract
It has been well accepted that hepatic drug extraction depends on the blood flow, vascular binding, transmembrane barriers, transporters, enzymes and cosubstrate and their zonal heterogeneity. Models of hepatic drug clearances have been appraised with respect to their utility in predicting drug removal by the liver. Among these models, the "well-stirred" model is the simplest since it assumes venous equilibration, with drug emerging from the outflow being in equilibrium with drug within the liver, and the concentration is the same throughout. The "parallel tube" and dispersion models, and distributed model of Goresky and co-workers have been used to account for the observed sinusoidal concentration gradient from the inlet and outlet. Departure from these models exists to include heterogeneity in flow, enzymes, and transporters. This article utilized the physiologically based pharmacokinetic (PBPK) liver model and its extension that include heterogeneity in enzymes and transporters to illustrate how in vitro uptake and metabolic data from zonal hepatocytes on transport and enzymes may be used to predict the kinetics of removal in the intact liver; binding data were also necessary. In doing so, an integrative platform was provided to examine determinants of hepatic drug clearance. We used enalapril and digoxin as examples, and described a simple liver PBPK model that included transmembrane transport and metabolism occurring behind the membrane, and a zonal model in which the PBPK model was expanded three sets of sub-compartments that are arranged sequentially to represent zones 1, 2, and 3 along the flow path. The latter model readily accommodated the heterogeneous distribution of hepatic enzymes and transporters. Transport and metabolic data, piecewise information that served as initial estimates, allowed for the unknown efflux and other intrinsic clearances to be estimated. The simple or zonal PBPK model provides predictive views on the hepatic removal of drugs and metabolites.
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Affiliation(s)
- Lichuan Liu
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, 19 Russell Street, Toronto, Ontario, Canada M5S 2S2
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Liu S, Tam D, Chen X, Pang KS. P-Glycoprotein and an Unstirred Water Layer Barring Digoxin Absorption in the Vascularly Perfused Rat Small Intestine Preparation: Induction Studies with Pregnenolone-16α-carbonitrile. Drug Metab Dispos 2006; 34:1468-79. [PMID: 16751264 DOI: 10.1124/dmd.105.008227] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Digoxin, a substrate of P-glycoprotein (Pgp) and cytochrome P450 3a (Cyp3a), was used to illustrate the inductive effects of pregnenolone-16alpha-carbonitrile (PCN), a ligand of the pregnane X receptor, on the absorption and disposition of [3H]digoxin in the vascularly perfused rat small intestine preparation. Although increased Cyp3a protein was observed with Western blotting analysis after PCN treatment, metabolism of digoxin to the digoxigenin bis-digitoxoside metabolite in the rat small intestine remained insignificant (<4% dose). PCN pretreatment significantly decreased blood perfusate [3H]digoxin concentrations for both systemic and intraluminal administrations of [3H]digoxin due to increased Pgp levels. The apical secretion by Pgp increased at 90 min with PCN treatment, from 11.2 +/- 5.1% of dose to 20.1 +/- 8.6% of dose after systemic administration of [3H]digoxin; this increase was, however, statistically insignificant (P = 0.13) because of the high variability among preparations. When the composite data for the control and PCN-treated preparations were fit to published physiologically based pharmacokinetic models: the traditional model and the segregated flow model, suboptimal parameters were obtained. The data were further fit to expanded models with a bilayer membrane compartment housing the Pgp adjacent to the apical membrane, or an unstirred water layer (UWL) external to the apical membrane. The models with the UWL yielded improved fits and reasonable parameters associated with digoxin absorption, suggesting that the UWL posed as a barrier for digoxin absorption. Similar results were obtained with the segmental models (the segmental traditional model and the segmental segregated flow model) using the UWL, when heterogeneous distributions of Pgp in the duodenum, jejunum, and ileum were considered.
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Affiliation(s)
- Shanjun Liu
- Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario, Canada
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Doherty MM, Poon K, Tsang C, Pang KS. Transport is not rate-limiting in morphine glucuronidation in the single-pass perfused rat liver preparation. J Pharmacol Exp Ther 2006; 317:890-900. [PMID: 16464965 DOI: 10.1124/jpet.105.100446] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Binding, transport, and metabolism are factors that influence morphine (M) removal in the rat liver. For M and the morphine 3beta-glucuronide metabolite (M3G), modest binding existed with 4% bovine serum albumin (unbound fractions of 0.89 +/- 0.07 and 0.98 +/- 0.09, respectively), and there was partitioning of M into red blood cells. Transport studies of M (<750 microM) showed similar, concentration-independent uptake clearances (CLs) of 1.5 ml min(-1) g(-1) among zonal and homogeneous, isolated rat hepatocytes. Transport of M3G, ascertained in multiple indicator dilution studies at various steady-state M3G concentrations (10-262 microM), uncovered a low and concentration-independent influx clearance (<10% of flow rate). The outflow dilution curve of [(3)H]M3G was superimposable onto that of [(14)C]sucrose, the extracellular reference, displaying similarity in transit times (23.5 and 22.2 s), negligible biliary excretion, and almost complete dose recovery from perfusate. In contrast, M3G occurred abundantly in both perfusate and bile in single-pass perfusion studies of the precursor, M, and revealed a biliary clearance of formed M3G that was 12.3-fold that of preformed M3G, suggesting a sinusoidal, diffusional barrier for M3G. With increasing concentrations of M (9-474 microM), clearance decreased, and metabolism and biliary excretion displayed concentration-dependent kinetics. Fitting of the data to a physiologically based liver model revealed that M removal mechanisms were saturable, with a K(m,met) of 52.2 microM and V(max,met) of 58.8 nmol min(-1) g(-1) for metabolism, and a K(m,ex) of 41.2 microM and V(max,ex) of 8.1 nmol min(-1) g(-1) for excretion. Sinusoidal transport was not rate-limiting for M removal.
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Affiliation(s)
- Margaret M Doherty
- Department of Pharmaceutical Sciences, Faculty of Pharmacy, University of Toronto, 19 Russell St., Toronto, ON, Canada M5S 2S2
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