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Balhara A, Yin M, Unadkat JD. Successful Prediction of Fetal Exposure to Dual BCRP/P-gp Drug Substrates Using the Efflux Ratio-Relative Expression Factor Approach and PBPK M&S. Clin Pharmacol Ther 2024; 115:1044-1053. [PMID: 38124355 DOI: 10.1002/cpt.3157] [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: 08/29/2023] [Accepted: 12/08/2023] [Indexed: 12/23/2023]
Abstract
To inform fetal drug safety, it is important to determine or predict fetal drug exposure throughout pregnancy. The former is not possible in the first or second trimester. In contrast, at the time of birth, fetal drug exposure, relative to maternal exposure, can be estimated as Kp,uu (unbound fetal umbilical venous (UV) plasma area under the curve (AUC)/unbound maternal plasma (MP) AUC), provided the observed UV/MP values, spanning the dosing interval, are available from multiple maternal-fetal dyads. However, this fetal Kp,uu cannot be extrapolated to other drugs. To overcome the above limitations, we have used an efflux ratio-relative expression factor (ER-REF) approach to successfully predict the fetal Kp,uu of P-gp substrates. Because many drugs taken by pregnant people are also BCRP substrates, here, we extend this approach to drugs that are effluxed by both placental BCRP and P-gp or P-gp alone. To verify our predictions, we chose drugs for which UV/MP data were available at term: glyburide and imatinib (both BCRP and P-gp substrates) and nelfinavir (only P-gp substrate). First, the ER of the drugs was determined using Transwells and MDCKII cells expressing either BCRP or P-gp. Then, the ER was scaled using the proteomics-informed REF value to predict the fetal Kp,uu of the drug at term. The ER-REF predicted fetal Kp,uu of glyburide (0.43), imatinib (0.42), and nelfinavir (0.40) fell within two-fold of the corresponding in vivo fetal Kp,uu (0.44, 0.37, and 0.46, respectively). These data confirm that the ER-REF approach can successfully predict fetal drug exposure to BCRP/P-gp and P-gp substrates, at term.
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Affiliation(s)
- Ankit Balhara
- Department of Pharmaceutics, University of Washington, Seattle, Washington, USA
| | - Mengyue Yin
- Department of Pharmaceutics, University of Washington, Seattle, Washington, USA
| | - Jashvant D Unadkat
- Department of Pharmaceutics, University of Washington, Seattle, Washington, USA
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Peng J, Ladumor MK, Unadkat JD. Estimation of fetal-to-maternal unbound steady-state plasma concentration ratio (Kp,uu,fetal ) of P-gp and/or BCRP substrate drugs using a maternal-fetal PBPK model. Drug Metab Dispos 2022; 50:613-623. [PMID: 35149540 PMCID: PMC9073947 DOI: 10.1124/dmd.121.000733] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 01/18/2022] [Indexed: 11/22/2022] Open
Abstract
Pregnant women are frequently prescribed drugs to treat chronic diseases (e.g., HIV infection), but little is known about the benefits and risks of these drugs to the fetus which are driven by fetal drug exposure. The latter can be estimated by fetal-to-maternal unbound plasma concentration at steady-state (Kp,uu,fetal). For drugs that are substrates of placental efflux transporters (i.e., P-gp or BCRP), is expected to be <1. Here, we estimated the in vivo of selective P-gp and/or BCRP substrate drugs by maternal-fetal (m-f)-PBPK modeling of umbilical vein (UV) plasma and maternal plasma (MP) concentrations obtained simultaneously at term from multiple maternal-fetal dyads. To do so, three drugs were selected: nelfinavir (P-gp substrate), efavirenz (BCRP substrate), and imatinib (P-gp/BCRP substrate). A m-f-PBPK model for each drug was developed and validated for the non-pregnant population and pregnant women using the Simcyp simulator (v20). Then, after incorporating placental passive diffusion clearance, the in vivo of the drug was estimated by adjusting the placental efflux clearance until the predicted UV/MP values best matched the observed data ( nelfinavir=0.41, efavirenz=0.39, imatinib=0.35). Furthermore, of nelfinavir and efavirenz at gestational week (GW) 25 and 15 were predicted to be 0.34, 0.23 and 0.33, 0.27 respectively. These values can be used to adjust dosing regimens of these drugs to optimize maternal-fetal drug therapy throughout pregnancy, to assess fetal benefits and risks of these dosing regimens, and to determine if these estimated in vivo values can be predicted from in vitro studies. Significance Statement The in vivo Kp,uu,fetal of nelfinavir (P-gp substrate), efavirenz (BCRP substrate), and imatinib (P-gp and BCRP substrate) was successfully estimated using m-f- PBPK modeling. These Kp,uu,fetal values can be used to adjust dosing regimens of these drugs to optimize maternal-fetal drug therapy throughout pregnancy, to assess fetal benefits and risks of these dosing regimens, and to determine if these estimated in vivo Kp,uu,fetal values can be predicted from in vitro studies.
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Affiliation(s)
- Jinfu Peng
- Department of Pharmacy, The Third Xiangya Hospital, Central South University, China
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Sharma P, Singh N, Sharma S. ATP binding cassette transporters and cancer: revisiting their controversial role. Pharmacogenomics 2021; 22:1211-1235. [PMID: 34783261 DOI: 10.2217/pgs-2021-0116] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The expression of ATP-binding cassette transporter (ABC transporters) has been reported in various tissues such as the lung, liver, kidney, brain and intestine. These proteins account for the efflux of different compounds and metabolites across the membrane, thus decreasing the concentration of the toxic compounds. ABC transporter genes play a vital role in the development of multidrug resistance, which is the main obstacle that hinders the success of chemotherapy. Preclinical and clinical trials have investigated the probability of overcoming drug-associated resistance and substantial toxicities. The focus has been put on several strategies to overcome multidrug resistance. These strategies include the development of modulators that can modulate ABC transporters. This knowledge can be translated for clinical oncology treatment in the future.
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Affiliation(s)
- Parul Sharma
- Department of Biotechnology, Thapar Institute of Engineering & Technology, Patiala, India
| | - Navneet Singh
- Department of Pulmonary medicine, Post Graduate Institute of Medical Education & Research, Chandigarh, India
| | - Siddharth Sharma
- Department of Biotechnology, Thapar Institute of Engineering & Technology, Patiala, India
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Effects of Phytochemical P-Glycoprotein Modulators on the Pharmacokinetics and Tissue Distribution of Doxorubicin in Mice. Molecules 2018; 23:molecules23020349. [PMID: 29414892 PMCID: PMC6017107 DOI: 10.3390/molecules23020349] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 01/26/2018] [Accepted: 01/31/2018] [Indexed: 12/02/2022] Open
Abstract
Pungent spice constituents such as piperine, capsaicin and [6]-gingerol consumed via daily diet or traditional Chinese medicine, have been reported to possess various pharmacological activities. These dietary phytochemicals have also been reported to inhibit P-glycoprotein (P-gp) in vitro and act as an alternative to synthetic P-gp modulators. However, the in vivo effects on P-gp inhibition are currently unknown. This study aimed to test the hypothesis that phytochemical P-gp inhibitors, i.e., piperine, capsaicin and [6]-gingerol, modulate the in vivo tissue distribution of doxorubicin, a representative P-gp substrate. Mice were divided into four groups and each group was pretreated with intraperitoneal injections of control vehicle, piperine, capsaicin, or [6]-gingerol and doxorubicin (1 mg/kg) was administered via the penile vein. The concentrations of the phytochemicals and doxorubicin in the plasma and tissues were determined by LC-MS/MS. The overall plasma concentration-time profiles of doxorubicin were not significantly affected by piperine, capsaicin, or [6]-gingerol. In contrast, doxorubicin accumulation was observed in tissues pretreated with piperine or capsaicin. The tissue to plasma partition coefficients, Kp, for the liver and kidney were higher in the piperine-pretreated group, while the Kp for kidney, brain and liver were higher in the capsaicin-pretreated group. [6]-Gingerol did not affect doxorubicin tissue distribution. The data demonstrated that the phytochemicals modulated doxorubicin tissue distribution, which suggested their potential to induce food-drug interactions and act as a strategy for the delivery of P-gp substrate drugs to target tissues and tumors.
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Zarebkohan A, Najafi F, Moghimi HR, Hemmati M, Deevband MR, Kazemi B. Synthesis and characterization of a PAMAM dendrimer nanocarrier functionalized by SRL peptide for targeted gene delivery to the brain. Eur J Pharm Sci 2015; 78:19-30. [PMID: 26118442 DOI: 10.1016/j.ejps.2015.06.024] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 06/17/2015] [Accepted: 06/25/2015] [Indexed: 12/22/2022]
Abstract
Blood-brain barrier inhibits most of drugs and genetic materials from reaching the brain. So, developing high efficiency carriers for gene and drug delivery to the brain, is the challenging area in pharmaceutical sciences. This investigation aimed to target DNA to brain using Serine-Arginine-Leucine (SRL) functionalized PAMAM dendrimers as a novel gene delivery system. The SRL peptide was linked on G4 PAMAM dendrimers using bifunctional PEG. DNA was then loaded in these functionalized nanoparticles and their physicochemical properties and cellular uptake/distribution evaluated by AFM, NMR, FTIR and fluorescence and confocal microscopy. Also, biodistribution and brain localization of nanoparticles were studied after IV injection of nanoparticles into rat tail. Unmodified nanoparticles were used as control in all evaluations. In vitro studies showed that SRL-modified nanoparticles have good transfection efficacy and low toxicity. Results also showed that SRL is a LRP ligand and SRL-modified nanoparticles internalized by clathrin/caveolin energy-dependent endocytosis to brain capillary endothelial cells. After intravenous administration, the SRL-modified nanoparticles were able to cross the blood-brain barrier and enter the brain parenchyma. Our result showed that, SRL-modified nanoparticles provide a safe and effective nanocarrier for brain gene delivery.
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Affiliation(s)
- Amir Zarebkohan
- Biomedical Engineering and Medical Physics Department, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Farhood Najafi
- Department of Resin and Additives, Institute for Color Science and Technology, Tehran, Iran
| | - Hamid Reza Moghimi
- School of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad Hemmati
- Biomedical Engineering and Medical Physics Department, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad Reza Deevband
- Biomedical Engineering and Medical Physics Department, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Bahram Kazemi
- Department of Biotechnology, Faculty of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Cellular and Molecular Biology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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Nagar S, Tucker J, Weiskircher EA, Bhoopathy S, Hidalgo IJ, Korzekwa K. Compartmental models for apical efflux by P-glycoprotein--part 1: evaluation of model complexity. Pharm Res 2014; 31:347-59. [PMID: 24019023 PMCID: PMC3946900 DOI: 10.1007/s11095-013-1164-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Accepted: 07/28/2013] [Indexed: 01/16/2023]
Abstract
PURPOSE With the goal of quantifying P-gp transport kinetics, Part 1 of these manuscripts evaluates different compartmental models and Part 2 applies these models to kinetic data. METHODS Models were developed to simulate the effect of apical efflux transporters on intracellular concentrations of six drugs. The effect of experimental variability on model predictions was evaluated. Several models were evaluated, and characteristics including membrane configuration, lipid content, and apical surface area (asa) were varied. RESULTS Passive permeabilities from MDCK-MDR1 cells in the presence of cyclosporine gave lower model errors than from MDCK control cells. Consistent with the results in Part 2, model configuration had little impact on calculated model errors. The 5-compartment model was the simplest model that reproduced experimental lag times. Lipid content and asa had minimal effect on model errors, predicted lag times, and intracellular concentrations. Including endogenous basolateral uptake activity can decrease model errors. Models with and without explicit membrane barriers differed markedly in their predicted intracellular concentrations for basolateral drug exposure. Single point data resulted in clearances similar to time course data. CONCLUSIONS Compartmental models are useful to evaluate the impact of efflux transporters on intracellular concentrations. Whereas a 3-compartment model may be sufficient to predict the impact of transporters that efflux drugs from the cell, a 5-compartment model with explicit membranes may be required to predict intracellular concentrations when efflux occurs from the membrane. More complex models including additional compartments may be unnecessary.
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Affiliation(s)
- Swati Nagar
- Department of Pharmaceutical Sciences, Temple University School of Pharmacy, Philadelphia PA
| | - Jalia Tucker
- Department of Pharmaceutical Sciences, Temple University School of Pharmacy, Philadelphia PA
| | | | | | | | - Ken Korzekwa
- Department of Pharmaceutical Sciences, Temple University School of Pharmacy, Philadelphia PA
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Döring B, Petzinger E. Phase 0 and phase III transport in various organs: combined concept of phases in xenobiotic transport and metabolism. Drug Metab Rev 2014; 46:261-82. [PMID: 24483608 DOI: 10.3109/03602532.2014.882353] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The historical phasing concept of drug metabolism and elimination was introduced to comprise the two phases of metabolism: phase I metabolism for oxidations, reductions and hydrolyses, and phase II metabolism for synthesis. With this concept, biological membrane barriers obstructing the accessibility of metabolism sites in the cells for drugs were not considered. The concept of two phases was extended to a concept of four phases when drug transporters were detected that guided drugs and drug metabolites in and out of the cells. In particular, water soluble or charged drugs are virtually not able to overcome the phospholipid membrane barrier. Drug transporters belong to two main clusters of transporter families: the solute carrier (SLC) families and the ATP binding cassette (ABC) carriers. The ABC transporters comprise seven families with about 20 carriers involved in drug transport. All of them operate as pumps at the expense of ATP splitting. Embedded in the former phase concept, the term "phase III" was introduced by Ishikawa in 1992 for drug export by ABC efflux pumps. SLC comprise 52 families, from which many carriers are drug uptake transporters. Later on, this uptake process was referred to as the "phase 0 transport" of drugs. Transporters for xenobiotics in man and animal are most expressed in liver, but they are also present in extra-hepatic tissues such as in the kidney, the adrenal gland and lung. This review deals with the function of drug carriers in various organs and their impact on drug metabolism and elimination.
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Affiliation(s)
- Barbara Döring
- Institute of Pharmacology and Toxicology, Biomedical Research Center Seltersberg, Justus-Liebig-University Giessen , Giessen , Germany
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Montesinos RN, Moulari B, Gromand J, Beduneau A, Lamprecht A, Pellequer Y. Coadministration of P-glycoprotein modulators on loperamide pharmacokinetics and brain distribution. Drug Metab Dispos 2014; 42:700-6. [PMID: 24398461 DOI: 10.1124/dmd.113.055566] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The efflux transporter P-glycoprotein, expressed at high levels at the blood-brain barrier, exerts a profound effect on the disposition of various therapeutic compounds in the brain. A rapid and efficient modulation of this efflux transporter could enhance the distribution of its substrates and thereby improve central nervous system pharmacotherapies. This study explored the impact of the intravenous coadministration of two P-glycoprotein modulators, tariquidar and elacridar, on the pharmacokinetics and brain distribution of loperamide, a P-glycoprotein substrate probe, in rats. After 1 hour postdosing, tariquidar and elacridar, both at a dose of 1.0 mg/kg, increased loperamide levels in the brain by 2.3- and 3.5-fold, respectively. However, the concurrent administration of both P-glycoprotein modulators, each at a dose of 0.5 mg/kg, increased loperamide levels in the brain by 5.8-fold and resulted in the most pronounced opioid-induced clinical signs. This phenomenon may be the result of a combined noncompetitive modulation by tariquidar and elacridar. Besides, the simultaneous administration of elacridar and tariquidar did not significantly modify the pharmacokinetic parameters of loperamide. This observation potentially allows the concurrent use of low but therapeutic doses of P-gp modulators to achieve full inhibitory effects.
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Affiliation(s)
- Rita Nieto Montesinos
- Laboratory of Pharmaceutical Engineering, University of Franche-Comté, Besançon, France
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Abstract
Research in the many areas of HIV treatment, eradication and prevention has necessitated measurement of antiretroviral (ARV) concentrations in nontraditional specimen types. To determine the knowledgebase of critical details for accurate bioanalysis, a review of the literature was performed and summarized. Bioanalytical assays for 31 ARVs, including metabolites, were identified in 205 publications measuring various tissues and biofluids. 18 and 30% of tissue or biofluid methods, respectively, analyzed more than one specimen type; 35-37% of the tissue or biofluid methods quantitated more than one ARV. 20 and 76% of tissue or biofluid methods, respectively, were used for the analysis of human specimens. HPLC methods with UV detection predominated, but chronologically MS detection began to surpass. 40% of the assays provided complete intra- and inter-assay validation data, but only 9% of publications provided any stability data with even less for the prevalent ARV in treatments.
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Michaud V, Bar-Magen T, Turgeon J, Flockhart D, Desta Z, Wainberg MA. The Dual Role of Pharmacogenetics in HIV Treatment: Mutations and Polymorphisms Regulating Antiretroviral Drug Resistance and Disposition. Pharmacol Rev 2012; 64:803-33. [DOI: 10.1124/pr.111.005553] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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11
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Lan X, Kiyota T, Hanamsagar R, Huang Y, Andrews S, Peng H, Zheng JC, Swindells S, Carlson GA, Ikezu T. The effect of HIV protease inhibitors on amyloid-β peptide degradation and synthesis in human cells and Alzheimer's disease animal model. J Neuroimmune Pharmacol 2012; 7:412-23. [PMID: 21826404 PMCID: PMC3223330 DOI: 10.1007/s11481-011-9304-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2011] [Accepted: 08/01/2011] [Indexed: 01/09/2023]
Abstract
Combined antiretroviral therapy (ART) tremendously improved the lifespan and symptoms associated with AIDS-defining illness in affected individuals. However, chronic ART-treated patients frequently develop age-dependent complications, including dementia, diabetes, and hyperlipidemia: all risk factors of Alzheimer's disease. Importantly, the effect of ART compounds on amyloid generation and clearance has never been systematically examined. Nine prescribed HIV protease inhibitors were tested for their effect on amyloid-β peptide (Aβ) clearance in primary cultured human monocyte-derived macrophages. Atazanavir, ritonavir, and saquinavir modestly inhibited of Aβ degradation, while lopinavir, nelfinavir, and ritonavir enhanced secretion of undigested Aβ after phagocytosis. Lopinavir, nelfinavir, ritonavir, and saquinavir inhibited endogenous Aβ40 production from primary cultured human cortical neurons, which were associated with reduction in Beta-site APP Converting Enzyme 1 (BACE1) and γ-secretase enzyme activities. However, ART compounds showed little inhibition of purified BACE1 activity in vitro, suggesting the indirect effect of ART compounds on BACE1 activity in neurons. Finally, nefinavir or lopinavir/ritonavir (Kaletra) were orally administered for 30 days into APP SCID mice expressing a double mutant form of APP 695 (KM670/671NL + V717F) in homozygosity for the scid allele of Prkdc. There was no difference in beta-amyloidosis by ART drug administration as determined by both immunohistochemistry and ELISA measurements although the therapeutic doses of the ART compounds was present in the brain. These data demonstrated that ART drugs can inhibit Aβ clearance in macrophages and Aβ production in neurons, but these effects did not significantly alter Aβ accumulation in the mouse brain.
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Affiliation(s)
- Xiqian Lan
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198-5880, USA
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12
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Wong HL, Wu XY, Bendayan R. Nanotechnological advances for the delivery of CNS therapeutics. Adv Drug Deliv Rev 2012; 64:686-700. [PMID: 22100125 DOI: 10.1016/j.addr.2011.10.007] [Citation(s) in RCA: 341] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Accepted: 10/27/2011] [Indexed: 12/18/2022]
Abstract
Effective non-invasive treatment of neurological diseases is often limited by the poor access of therapeutic agents into the central nervous system (CNS). The majority of drugs and biotechnological agents do not readily permeate into brain parenchyma due to the presence of two anatomical and biochemical dynamic barriers: the blood-brain barrier (BBB) and blood-cerebrospinal fluid barrier (BCSFB). Therefore, one of the most significant challenges facing CNS drug development is the availability of effective brain targeting technology. Recent advances in nanotechnology have provided promising solutions to this challenge. Several nanocarriers ranging from the more established systems, e.g. polymeric nanoparticles, solid lipid nanoparticles, liposomes, micelles to the newer systems, e.g. dendrimers, nanogels, nanoemulsions and nanosuspensions have been studied for the delivery of CNS therapeutics. Many of these nanomedicines can be effectively transported across various in vitro and in vivo BBB models by endocytosis and/or transcytosis, and demonstrated early preclinical success for the management of CNS conditions such as brain tumors, HIV encephalopathy, Alzheimer's disease and acute ischemic stroke. Future development of CNS nanomedicines need to focus on increasing their drug-trafficking performance and specificity for brain tissue using novel targeting moieties, improving their BBB permeability and reducing their neurotoxicity.
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13
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Weiss M. Functional characterization of drug uptake and metabolism in the heart. Expert Opin Drug Metab Toxicol 2011; 7:1295-306. [DOI: 10.1517/17425255.2011.614233] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Ashraf T, Ronaldson PT, Persidsky Y, Bendayan R. Regulation of P-glycoprotein by human immunodeficiency virus-1 in primary cultures of human fetal astrocytes. J Neurosci Res 2011; 89:1773-82. [PMID: 21826700 DOI: 10.1002/jnr.22720] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Revised: 04/28/2011] [Accepted: 05/19/2011] [Indexed: 01/04/2023]
Abstract
P-glycoprotein (P-gp), a drug efflux pump, is known to alter the bioavailability of antiretroviral drugs at several sites, including the brain. We have previously shown that human immunodeficiency virus-1 (HIV-1) glycoprotein 120 (gp120) induces proinflammatory cytokine secretion and decreases P-gp functional expression in rat astrocytes, a cellular reservoir of HIV-1. However, whether P-gp is regulated in a similar way in human astrocytes is unknown. This study investigates the regulation of P-gp in an in vitro model of gp120-triggered human fetal astrocytes (HFAs). In this system, elevated levels of interleukin-6 (IL-6), IL-1β, and tumor necrosis factor-α were detected in culture supernatants. Pretreatment with CCR5 neutralizing antibody attenuated cytokine secretion, suggesting that gp120-CCR5 interaction mediated cytokine production. Treatment with gp120 (R5-tropic) resulted in reduced P-gp expression (64%) and function as determined by increased (1.6-fold) cellular accumulation of [(3) H]digoxin, a P-gp substrate. Exposure to R5 or R5/X4-tropic viral isolates led to a downregulation in P-gp expression (75% or 90%, respectively), and treatment with IL-6 also showed lower P-gp expression (50%). Moreover, IL-6 neutralizing antibody blocked gp120-mediated P-gp downregulation, suggesting that IL-6 is a key modulator of P-gp. Gp120- or IL-6-mediated downregulation of P-gp was attenuated by SN50 (a nuclear factor-κB [NF-κB] inhibitor), suggesting involvement of NF-κB signaling in P-gp regulation. Our results suggest that, similarly to the case with rodent astrocytes, pathophysiological stressors associated with brain HIV-1 infection have a downregulatory effect on P-gp functional expression in human astrocytes, which may ultimately result in altered antiretroviral drug accumulation within brain parenchyma.
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Affiliation(s)
- Tamima Ashraf
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
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15
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Crouthamel MH, Kelly EJ, Ho RJY. Development and characterization of transgenic mouse models for conditional gene knockout in the blood-brain and blood-CSF barriers. Transgenic Res 2011; 21:113-30. [PMID: 21538071 DOI: 10.1007/s11248-011-9512-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Accepted: 04/13/2011] [Indexed: 12/11/2022]
Abstract
For many CNS acting drugs, penetration into the central nervous system (CNS) is limited by the blood-CNS-barriers. In an effort to quantitate the role of the protein components that make up the blood-CNS-barriers, we created transgenic mice that allow conditional gene knockout using Cre/loxP technology. We targeted the expression of Cre-recombinase to the choroid plexus (the blood-cerebral spinal fluid barrier) using the lymphotropic papovavirus control region (LPVcr) and to brain endothelium (the blood-brain-barrier) using the proximal promoter region of the human von Willebrand Factor gene (hVWF-f). We verified that LPVcr restricts expression to the choroid plexus in adult mice by using the LPVcr to drive n-LacZ expression in transgenic mice. The LPV-Cre and hVWF-Cre plasmids were then constructed and tested for Cre-recombinase function in vitro, and subsequently used to create transgenic mice. The resulting transgenic mice were characterized for cell-type specific Cre-mediated endonuclease activity by crossing them with transgenic mice containing a loxP-flanked-LacZ/EGFP dual reporter gene Z/EG. The dual Cre-Z/EG transgenic offspring were evaluated for the location of EGFP mRNA expression by reverse transcriptase PCR and for protein expression by immunohistochemistry. Immunohistochemistry for EGFP verified expression in the target cells, and no ectopic expression outside of the expected cell types. The LPV-Cre.0607 transgenic line expressed functional Cre only in the choroid plexus and hVWF-Cre.1304 line in brain endothelium.
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Affiliation(s)
- Matthew H Crouthamel
- Department of Pharmaceutics, University of Washington, Box 357610, Seattle, WA 98195-7610, USA
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16
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Moerman L, Wyffels L, Slaets D, Raedt R, Boon P, De Vos F. Antiepileptic drugs modulate P-glycoproteins in the brain: a mice study with (11)C-desmethylloperamide. Epilepsy Res 2011; 94:18-25. [PMID: 21277169 DOI: 10.1016/j.eplepsyres.2010.12.013] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2010] [Revised: 12/01/2010] [Accepted: 12/27/2010] [Indexed: 12/18/2022]
Abstract
P-glycoprotein transporters (P-gp) located at the blood-brain barrier (BBB) are likely to play a role in refractory epilepsy. In vitro studies already pointed out that several antiepileptic drugs (AEDs) are substrate of P-gp. This study proposes a new in vivo approach to investigate the interaction between some AEDs and P-gp located at the BBB. (11)C-desmethylloperamide ((11)C-dLop), a radiolabelled substrate of P-gp, was intravenously administrated after pretreatment with saline or AEDs (sodium valproate, levetiracetam, topiramate and phenytoin) at their human therapeutic and four times their therapeutic dose. The effect of the different pretreatment on the intracerebral concentration of (11)C-dLop was determined to indirectly investigate possible in vivo interactions between AEDs and P-gp. Pretreatment with levetiracetam, topiramate and phenytoin at therapeutic doses significantly decreased intracerebral concentration of (11)C-dLop. Pretreatment with a therapeutic dose of sodium valproate did not influence brain uptake of (11)C-dLop. In case of pretreatment with supratherapeutic doses of AED, (11)C-dLop brain uptake was not different compared to pretreatment with saline. The metabolisation rate of (11)C-dLop in plasma was unaltered, indicating that observed differences in brain uptake of the tracer were not due to pharmacokinetic changes. The following conclusion can be made: levetiracetam, topiramate and phenytoin demonstrate biphasic modulation of the BBB P-gp. At therapeutic doses they act as inducers of efflux, at supratherapeutic doses they have no effect on the efflux rate. Sodium valproate does not interact with P-gp at therapeutic nor at higher doses.
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Affiliation(s)
- Lieselotte Moerman
- Laboratory of Radiopharmacy, Ghent University, Harelbekestraat 72, B-9000 Ghent, Belgium.
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17
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Crouthamel MH, Wu D, Yang Z, Ho RJY. A novel MDR1 GT1292-3TG (Cys431Leu) genetic variation and its effect on P-glycoprotein biologic functions. AAPS JOURNAL 2010; 12:548-55. [PMID: 20623213 DOI: 10.1208/s12248-010-9216-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2010] [Accepted: 06/18/2010] [Indexed: 01/08/2023]
Abstract
P-glycoprotein (P-gp) is a membrane-bound transporter protein that is encoded by the human multidrug resistance gene MDR1 (ABCB1). P-gp recognizes a wide range of xenobiotics, is pivotal in mediating cancer drug resistance, and plays an important role in limiting drug penetration across the blood-brain barrier. MDR1 genetic variation can lead to changes in P-gp function and may have implications on drug pharmacokinetics. We have identified a novel MDR1 (GT1292-3TG) (Cys431Leu) genetic variation through systematic profiling of subjects with leukemia. The cellular and transport function of this variation was investigated with recombinant human embryonic kidney cells expressing MDR1. Compared with the wild type, MDR1 (GT1292-3TG) recombinant cells exhibited a lower drug resistance phenotype for a panel of chemotherapeutic agents. When compared with wild type, MDR1 (GT1292-3TG) recombinant cells exposed exhibited a 75% decrease in IC₅₀ for doxorubicin (162.6 ± 17.4 to 37.9 ± 2.6 nM) and a 50% decrease in IC(50) for paclitaxel (155.7 ± 27.5 to 87.7 ± 9.2 nM), vinblastine (128.0 ± 15.9 to 65.9 ± 5.1 nM), and vincristine (593.7 ± 61.8 to 307.3 ± 17.0 nM). The effects of the Cys431Leu variation, due to MDR1 (GT1292-3TG) nucleotide transition, on P-gp-dependent intracellular substrate accumulation appeared to be substrate dependent where doxorubicin, vinblastine, and paclitaxel exhibit an increased accumulation (p < 0.05), while verapamil and Hoechst33342 exhibit a decreased intracellular concentration compared with wild type (p < 0.05). Collectively, these data suggest MDR1 (GT1292-3TG) variation of P-gp may reduce drug resistance and that subjects with this genotype undergoing chemotherapy with drugs that are transported by P-gp could potentially be more responsive to therapy than those with MDR1 wild-type genotype.
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18
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Weiss J, Haefeli WE. Impact of ATP-binding cassette transporters on human immunodeficiency virus therapy. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2010; 280:219-79. [PMID: 20797684 DOI: 10.1016/s1937-6448(10)80005-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Even though potent antiretrovirals are available against human immunodeficiency virus (HIV)-1 infection, therapy fails in a significant fraction of patients. Among the most relevant reasons for treatment failure are drug toxicity and side effects, but also the development of viral resistance towards the drugs applied. Efflux by ATP-binding cassette (ABC-) transporters represents one major mechanism influencing the pharmacokinetics of antiretroviral drugs and particularly their distribution, thus modifiying the concentration within the infected cells, that is, at the site of action. Moreover, drug-drug interactions may occur at the level of these transporters and modulate their activity or expression thus influencing the efficacy and toxicity of the substrate drugs. This review summarizes current knowledge on the interaction of antiretrovirals used for HIV-1 therapy with ABC-transporters and highlights the impact of ABC-transporters for cellular resistance and therapeutic success. Moreover, the suitability of different cell models for studying the interaction of antiretrovirals with ABC-transporters is discussed.
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Affiliation(s)
- Johanna Weiss
- Department of Clinical Pharmacology and Pharmacoepidemiology, University of Heidelberg, Heidelberg, Germany
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19
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Wong HL, Chattopadhyay N, Wu XY, Bendayan R. Nanotechnology applications for improved delivery of antiretroviral drugs to the brain. Adv Drug Deliv Rev 2010; 62:503-17. [PMID: 19914319 DOI: 10.1016/j.addr.2009.11.020] [Citation(s) in RCA: 130] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Accepted: 09/14/2009] [Indexed: 01/16/2023]
Abstract
Human immunodeficiency virus (HIV) can gain access to the central nervous system during the early course of primary infection. Once in the brain compartment the virus actively replicates to form an independent viral reservoir, resulting in debilitating neurological complications, latent infection and drug resistance. Current antiretroviral drugs (ARVs) often fail to effectively reduce the HIV viral load in the brain. This, in part, is due to the poor transport of many ARVs, in particular protease inhibitors, across the blood-brain barrier (BBB) and blood-cerebrospinal fluid barrier (BCSBF). Studies have shown that nanocarriers including polymeric nanoparticles, liposomes, solid lipid nanoparticles (SLN) and micelles can increase the local drug concentration gradients, facilitate drug transport into the brain via endocytotic pathways and inhibit the ATP-binding cassette (ABC) transporters expressed at the barrier sites. By delivering ARVs with nanocarriers, significant increase in the drug bioavailability to the brain is expected to be achieved. Recent studies show that the specificity and efficiency of ARVs delivery can be further enhanced by using nanocarriers with specific brain targeting, cell penetrating ligands or ABC-transporters inhibitors. Future research should focus on achieving brain delivery of ARVs in a safe, efficient, and yet cost-effective manner.
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20
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Jung N, Taubert D. Organic cation transporters and their roles in antiretroviral drug disposition. Expert Opin Drug Metab Toxicol 2010; 5:773-87. [PMID: 19519281 DOI: 10.1517/17425250902997959] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
BACKGROUND Understanding metabolising processes and drug-transporter interactions is particularly crucial to the management of patients with HIV infection, given the several antiretroviral drugs that must be taken lifelong and the use of other medications for HIV-related and non-HIV-related conditions. Several interactions of antiretroviral drugs with metabolising enzymes, especially cytochrome P450 and ATP-dependent transporter P-glycoprotein, have been described but the role of the organic cation transporters (OCTs) is less clearly defined. OBJECTIVE To review the relevance of the OCTs for antiretroviral drug disposition. METHODS Interactions of OCTs with antiretroviral drugs and evidence for clinical relevance are discussed. RESULTS/CONCLUSION Several antiretroviral drugs show relevant interactions with the OCTs in cell-based experiments and the OCTs are highly upregulated in HIV-infected patients. For evaluating the clinical significance, interaction studies in HIV patients and reliable in vitro models for delineation of in vivo effects are needed.
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Affiliation(s)
- Norma Jung
- University Hospital of Cologne, Department I of Internal Medicine, Cologne, Germany.
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21
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Hassan HE, Myers AL, Coop A, Eddington ND. Differential involvement of P-glycoprotein (ABCB1) in permeability, tissue distribution, and antinociceptive activity of methadone, buprenorphine, and diprenorphine: in vitro and in vivo evaluation. J Pharm Sci 2010; 98:4928-40. [PMID: 19370547 DOI: 10.1002/jps.21770] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Conclusions based on either in vitro or in vivo approach to evaluate the P-gp affinity status of opioids may be misleading. For example, in vitro studies indicated that fentanyl is a P-gp inhibitor while in vivo studies indicated that it is a P-gp substrate. Quite the opposite was evident for meperidine. The objective of this study was to evaluate the P-gp affinity status of methadone, buprenorphine and diprenorphine to predict P-gp-mediated drug-drug interactions and to determine a better candidate for management of opioid dependence. Two in vitro (P-gp ATPase and monolayer efflux) assays and two in vivo (tissue distribution and antinociceptive evaluation in mdr1a/b (-/-) mice) assays were used. Methadone stimulated the P-gp ATPase activity only at higher concentrations, while verapamil and GF120918 inhibited its efflux (p < 0.05). The brain distribution and antinociceptive activity of methadone were enhanced (p < 0.05) in P-gp knockout mice. Conversely, buprenorphine and diprenorphine were negative in all assays. P-gp can affect the PK/PD of methadone, but not buprenorphine or diprenorphine. Our report is in favor of buprenorphine over methadone for management of opioid dependence. Buprenorphine most likely is not a P-gp substrate and concerns regarding P-gp-mediated drug-drug interaction are not expected.
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Affiliation(s)
- Hazem E Hassan
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland, USA
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22
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Lee EJD, Lean CB, Limenta LMG. Role of membrane transporters in the safety profile of drugs. Expert Opin Drug Metab Toxicol 2010; 5:1369-83. [PMID: 19663740 DOI: 10.1517/17425250903176421] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
It has increasingly been recognized that few molecules move across the cell membrane without the assistance of transporter proteins. Large superfamilies of transporter proteins have been identified in every living cell, including microorganisms and mitochondria. This report reviews the role of transporters in physiology and pharmacology, and identifies where this may have an impact on drug efficacy and toxicity. This new understanding will require a fresh appreciation of pharmacokinetics and drug effects, as the current paradigms are based largely on the assumption that drug molecules have a reasonable unrestricted permeability across membranes. Rather than just focusing on clearance changes and central compartment pharmacokinetics, it will become increasingly necessary to examine the peripheral tissue distribution of drugs to more accurately predict drug efficacy and toxicity.
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Affiliation(s)
- Edmund Jon Deoon Lee
- National University of Singapore, Clinical Research Centre, Department of Pharmacology, Singapore.
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23
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Marathe PH, Rodrigues AD. Examination of CYP3A and P-glycoprotein-mediated drug-drug interactions using animal models. Methods Mol Biol 2010; 596:385-403. [PMID: 19949933 DOI: 10.1007/978-1-60761-416-6_17] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
With the advent of polytherapy for cancer treatment it has become prudent to minimize, as much as possible, the potential for drug-drug interactions (DDI). Toward this end, the metabolic and transporter pathways involved in the disposition of a drug candidate (phenotyping) and potential for inhibition and induction of drug-metabolizing enzymes and transporters are evaluated in vitro. Such in vitro human data can be made available prior to human dosing and enable in vitro to in vivo-based predictions of clinical outcomes. Despite some success, however, in vitro systems are not dynamic and sometimes fail to predict drug-drug interactions for a variety of reasons. In comparison, relatively less effort has been made to evaluate predictions based on data derived from in vivo animal models. This chapter will attempt to summarize different examples from the literature where animal models have been used to predict cytochrome P450 3A (CYP3A)- and P-glycoprotein-based DDI. When employing data from animal models one needs to be aware of species differences in enzyme- and transporter-activity leading to differences in pharmacokinetics, clearance pathways as well as species differences in selectivity and affinity of probe substrates and inhibitors. Because of these differences, in vivo animal studies alone, cannot be predictive of human DDI. Despite these caveats, the information obtained from validated in vivo animal models may prove useful when used in conjunction with in vitro-in vivo extrapolation methods. Such an integrated data set can be used to select drug candidates with a reduced DDI potential.
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Affiliation(s)
- Punit H Marathe
- Metabolism and Pharmacokinetics, Bristol-Myers Squibb, Pennington, NJ, USA.
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24
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Fujimoto H, Higuchi M, Watanabe H, Koh Y, Ghosh AK, Mitsuya H, Tanoue N, Hamada A, Saito H. P-glycoprotein mediates efflux transport of darunavir in human intestinal Caco-2 and ABCB1 gene-transfected renal LLC-PK1 cell lines. Biol Pharm Bull 2009; 32:1588-1593. [PMID: 19721237 PMCID: PMC6526530 DOI: 10.1248/bpb.32.1588] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/29/2023]
Abstract
Darunavir (DRV) is a nonpeptidic protease inhibitor (PI) approved for the treatment of human immunodeficiency virus (HIV) infection. DRV displays potent activity against HIV strains resistant to other available PIs. Coadministration with ritonavir (RTV) improves the oral bioavailability of DRV. Inhibition of cytochrome P450 by RTV has been proposed as a mechanism for enhanced DRV bioavailability. However, interaction of these drugs with intestinal transporters has not been elucidated. This study was performed to explore the involvement of P-glycoprotein in transcellular DRV transport in monolayers of human intestinal Caco-2 and in ABCB1 multidrug resistance 1, (MDR1) gene-transfected renal LLC-PK1 (L-MDR1) cell lines. Transepithelial transport of DRV in Caco-2 cell monolayers was 2-fold greater in the basal-to-apical direction compared to that in the opposite direction. RTV had a significant inhibitory effect on the efflux transport of DRV in Caco-2 cells. The apical-to-basal DRV transport was enhanced by P-glycoprotein inhibitors, cyclosporin A and verapamil, as well as multidrug resistance-related protein (MRP/ABCC) inhibitors, probenecid and MK571. Using the L-MDR1 cell line, basal-to-apical DRV transport was much greater than in the opposite direction. Furthermore, cyclosporin A markedly inhibited the basal-to-apical DRV transport. RTV significantly increased the apical-to-basal transport of DRV in L-MDR1 cells, but reduced transport in the opposite direction. DRV inhibited P-glycoprotein-mediated efflux of calcein-acetoxymethyl ester in L-MDR1 cells with the inhibitory potency of 121 microM. These findings suggest that DRV is a substrate of P-glycoprotein and MRP, most likely MRP2. RTV appeared to inhibit P-glycoprotein, thereby enhancing the absorptive transport of DRV.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B
- ATP Binding Cassette Transporter, Subfamily B, Member 1/antagonists & inhibitors
- ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics
- ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism
- ATP Binding Cassette Transporter, Subfamily B, Member 1/physiology
- Animals
- Biological Transport, Active/drug effects
- Biological Transport, Active/physiology
- Caco-2 Cells
- Darunavir
- Down-Regulation/drug effects
- Down-Regulation/physiology
- Humans
- Intestinal Mucosa/cytology
- Intestinal Mucosa/drug effects
- Intestinal Mucosa/metabolism
- Kidney/cytology
- Kidney/drug effects
- Kidney/metabolism
- LLC-PK1 Cells
- Sulfonamides/metabolism
- Swine
- Transfection/methods
- Up-Regulation/drug effects
- Up-Regulation/physiology
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Affiliation(s)
| | - Maiko Higuchi
- Department of Pharmacy, Kumamoto University Hospital
| | | | - Yasuhiro Koh
- Department of Hematology, Kumamoto University Graduate School of Medical and Pharmaceutical Sciences, Kumamoto University; 1–1–1 Honjo, Kumamoto 860–8556, Japan
| | - Arun K. Ghosh
- Departments of Chemistry and Medicinal Chemistry, Purdue University; West Lafayette, Indiana 47907, U.S.A
| | - Hiroaki Mitsuya
- Department of Hematology, Kumamoto University Graduate School of Medical and Pharmaceutical Sciences, Kumamoto University; 1–1–1 Honjo, Kumamoto 860–8556, Japan
| | - Naomi Tanoue
- Department of Pharmacy, Kumamoto University Hospital
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Eyal S, Hsiao P, Unadkat JD. Drug interactions at the blood-brain barrier: fact or fantasy? Pharmacol Ther 2009; 123:80-104. [PMID: 19393264 DOI: 10.1016/j.pharmthera.2009.03.017] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Accepted: 03/20/2009] [Indexed: 12/24/2022]
Abstract
There is considerable interest in the therapeutic and adverse outcomes of drug interactions at the blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSFB). These include altered efficacy of drugs used in the treatment of CNS disorders, such as AIDS dementia and malignant tumors, and enhanced neurotoxicity of drugs that normally penetrate poorly into the brain. BBB- and BCSFB-mediated interactions are possible because these interfaces are not only passive anatomical barriers, but are also dynamic in that they express a variety of influx and efflux transporters and drug metabolizing enzymes. Based on studies in rodents, it has been widely postulated that efflux transporters play an important role at the human BBB in terms of drug delivery. Furthermore, it is assumed that chemical inhibition of transporters or their genetic ablation in rodents is predictive of the magnitude of interaction to be expected at the human BBB. However, studies in humans challenge this well-established paradigm and claim that such drug interactions will be lesser in magnitude but yet may be clinically significant. This review focuses on current known mechanisms of drug interactions at the blood-brain and blood-CSF barriers and the potential impact of such interactions in humans. We also explore whether such drug interactions can be predicted from preclinical studies. Defining the mechanisms and the impact of drug-drug interactions at the BBB is important for improving efficacy of drugs used in the treatment of CNS disorders while minimizing their toxicity as well as minimizing neurotoxicity of non-CNS drugs.
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Affiliation(s)
- Sara Eyal
- Department of Pharmaceutics, School of Pharmacy, University of Washington, Seattle, Washington 98195, USA
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26
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Shaik N, Pan G, Elmquist WF. Interactions of pluronic block copolymers on P-gp efflux activity: experience with HIV-1 protease inhibitors. J Pharm Sci 2009; 97:5421-33. [PMID: 18393290 DOI: 10.1002/jps.21372] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The objective was to examine the influence of Pluronic block-copolymers on the interaction between the drug efflux transporter, P-glycoprotein and HIV-1 protease inhibitors (PIs). The ATPase assay determined the effect of various Pluronics on PI-stimulated P-gp ATPase activity. Cellular accumulation studies were conducted using MDCKII and LLC-PK1 cells transfected with human MDR1 to assess Pluronic modulation of PI efflux. Pluronic P85 inhibited both basal and nelfinavir-stimulated P-gp ATPase activity, while Pluronic F127 had no effect. In cell accumulation studies, Pluronic P85 restored the accumulation of nelfinavir in MDCKII-MDR1 cells while Pluronic F127 and F88 had no effect. Pluronic P85 increased saquinavir accumulation in wild-type and MDR1-transfected cells in both the MDCKII and LLC-PK1 cell models, suggesting inhibition of multiple transporters, including MRPs. In conclusion, this study provides evidence that a block-copolymer, Pluronic P85, effectively inhibits the interaction of P-gp with nelfinavir and saquinavir. These data indicate that effective inhibition of HIV-1 PI efflux by Pluronic P85 may influence the distribution of antiretroviral agents to sites protected by efflux mechanisms, such as the blood-brain barrier, and possibly increase the brain exposure of these drugs resulting in suppression of viral replication and reduction in the incidence of drug resistant mutants.
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Affiliation(s)
- Naveed Shaik
- Department of Pharmaceutics, College of Pharmacy, University of Minnesota, 308 Harvard St. SE, Room 9-125d, Weaver-Densford Hall, Minneapolis, Minnesota 55455, USA
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27
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Stanley LA, Horsburgh BC, Ross J, Scheer N, Wolf CR. Drug transporters: Gatekeepers controlling access of xenobiotics to the cellular interior. Drug Metab Rev 2009; 41:27-65. [DOI: 10.1080/03602530802605040] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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28
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Senthilkumari S, Velpandian T, Biswas NR, Sonali N, Ghose S. Evaluation of the impact of P-glycoprotein (P-gp) drug efflux transporter blockade on the systemic and ocular disposition of P-gp substrate. J Ocul Pharmacol Ther 2008; 24:290-300. [PMID: 18476799 DOI: 10.1089/jop.2007.0063] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
PURPOSE The impact of P-glycoprotein (P-gp) blockade on the intravenous (i.v.) pharmacokinetics of rhodamine-123 (Rho-123), and the subsequent effect on its disposition in ocular and nonocular tissues, was studied by using rabbits. METHODS Three (3) control rabbits received only an i.v. bolus dose of Rho-123 (1.52 mg/kg). Three (3) blocker-pretreated rabbits received an i.v. dose of GF120918 (3.5 mg/kg) 30 min before the i.v. bolus of Rho-123. The plasma concentration of Rho-123 at different time points was subjected to a pharmacokinetic compartmental analysis, using WinNonlin (Scientific Consultants, Lexington, KY). For tissue-distribution study, a drug treatment similar to the i.v. kinetic study was followed by having 5 rabbits in each group. The animals were sacrificed at 30 min with an excess of anesthesia. Plasma and tissues samples were analyzed by using a validated high-performance liquid chromatographic IV method with a fluorescent detector. RESULTS The method validated was sensitive enough to estimate Rho-123 up to 1.94 ng/mL in plasma. I.v. Rho-123 data fitted well into the three-compartment model, and P-gp blocker treatment changed it into a two-compartment model. The P-gp blockade significantly increased the mean tissue concentrations in the lungs and spleen, whereas the rise in mean tissue levels in the heart, liver, and kidney and in all ocular tissues were found to be statistically insignificant. CONCLUSIONS Increasing the ocular concentration of systemically given drugs may not be possible with the degree of P-gp blockade achieved when using GF120918 at the studied concentration after an i.v. administration.
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Affiliation(s)
- Srinivasan Senthilkumari
- Department of Ocular Pharmacology and Pharmacy, Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
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29
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Eilers M, Roy U, Mondal D. MRP (ABCC) transporters-mediated efflux of anti-HIV drugs, saquinavir and zidovudine, from human endothelial cells. Exp Biol Med (Maywood) 2008; 233:1149-60. [PMID: 18535159 DOI: 10.3181/0802-rm-59] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The constituents of highly active anti-retroviral therapy (HAART) include HIV-1 protease inhibitors (HPIs) and nucleoside reverse transcriptase inhibitors (NRTIs). Endothelial cell (EC) barriers, especially the blood-brain-barrier (BBB) suppresses the entry of HAART drugs to subendothelial HIV-1 reservoirs. The ATP binding cassette (ABC) transporter family members, multidrug resistant-1 (MDR-1) and multidrug resistance-associated proteins (MRPs) can efflux both HPIs and NRTIs from intracellular compartments. Using brain derived ECs from non-human sources, previous studies suggested a dominant role for MDR-1 in HAART efflux from the BBB. However, due to species variations in ABC-transporter expression, drug-efflux functions using human brain ECs need to be investigated. Furthermore, roles of ABC-transporters in drug-efflux from systemic EC barriers need to be studied. We monitored the expression of ABC-transporters in primary human ECs obtained from brain (HBMVECs), aorta (HAECs), pulmonary-artery (HPAECs), dermal-microvessel (HDMVECs) and umbilical vein (HUVECs). Gene expression for MDR-1 and MRPs (MRP-1 to MRP-5) were analyzed by reverse transcriptase polymerase chain reaction (RT-PCR). Drug efflux functions were determined by calcein retention assays. Intracellular accumulation of both 3H-saquinavir (an HPI) and 3H-zidovudine (an NRTI) were also monitored in HAECs and HBMVECs. Both assays were carried out in presence of verapamil (20-60 microM) or MK-571 (12.5-50 microM) inhibitors of MDR-1 and MRPs, respectively in presence of verapamil or MK-571. The HBMVECs expressed higher levels of MRPs than MDR-1 and only MK-571 significantly (P<0.01) suppressed calcein efflux from these cells. However, both HAECs and HPAECs showed MDR-1 and MRP expression and calcein efflux was inhibited by both verapamil and MK-571. Both inhibitors suppressed 3H-saqubinavir efflux from HAECs, but only MK-571 suppressed saquinavir efflux from HBMVECs. In both ECs, 3H-zidovudine efflux was only suppressed by MK-571. Thus, primary human ECs, especially brain derived ECs, predominantly express MRPs and their specific inhibition may enhance HAART efficacy in subendothelial HIV-1 reservoirs.
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Affiliation(s)
- Mark Eilers
- Department of Pharmacology, Tulane University Health Sciences Center, 1430 Tulane Avenue, SL-83, New Orleans, LA 70112, USA
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30
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Motl S, Zhuang Y, Waters CM, Stewart CF. Pharmacokinetic considerations in the treatment of CNS tumours. Clin Pharmacokinet 2007; 45:871-903. [PMID: 16928151 DOI: 10.2165/00003088-200645090-00002] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Despite aggressive therapy, the majority of primary and metastatic brain tumour patients have a poor prognosis with brief survival periods. This is because of the different pharmacokinetic parameters of systemically administered chemotherapeutic agents between the brain and the rest of the body. Specifically, before systemically administered drugs can distribute into the CNS, they must cross two membrane barriers, the blood-brain barrier (BBB) and blood-cerebrospinal fluid (CSF) barrier (BCB). To some extent, these structures function to exclude xenobiotics, such as anticancer drugs, from the brain. An understanding of these unique barriers is essential to predict when and how systemically administered drugs will be transported to the brain. Specifically, factors such as physiological variables (e.g. blood flow), physicochemical properties of the drug (e.g. molecular weight), as well as influx and efflux transporter expression at the BBB and BCB (e.g. adenosine triphosphate-binding cassette transporters) determine what compounds reach the CNS. A large body of preclinical and clinical research exists regarding brain penetration of anticancer agents. In most cases, a surrogate endpoint (i.e. CSF to plasma area under the concentration-time curve [AUC] ratio) is used to describe how effectively agents can be transported into the CNS. Some agents, such as the topoisomerase I inhibitor, topotecan, have high CSF to plasma AUC ratios, making them valid therapeutic options for primary and metastatic brain tumours. In contrast, other agents like the oral tyrosine kinase inhibitor, imatinib, have a low CSF to plasma AUC ratio. Knowledge of these data can have important clinical implications. For example, it is now known that chronic myelogenous leukaemia patients treated with imatinib might need additional CNS prophylaxis. Since most anticancer agents have limited brain penetration, new pharmacological approaches are needed to enhance delivery into the brain. BBB disruption, regional administration of chemotherapy and transporter modulation are all currently being evaluated in an effort to improve therapeutic outcomes. Additionally, since many chemotherapeutic agents are metabolised by the cytochrome P450 3A enzyme system, minimising drug interactions by avoiding concomitant drug therapies that are also metabolised through this system may potentially enhance outcomes. Specifically, the use of non-enzyme-inducing antiepileptic drugs and curtailing nonessential corticosteroid use may have an impact.
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Affiliation(s)
- Susannah Motl
- Department of Clinical Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA
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Obradovic T, Dobson GG, Shingaki T, Kungu T, Hidalgo IJ. Assessment of the First and Second Generation Antihistamines Brain Penetration and Role of P-Glycoprotein. Pharm Res 2006; 24:318-27. [PMID: 17180728 DOI: 10.1007/s11095-006-9149-4] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2006] [Accepted: 08/15/2006] [Indexed: 01/16/2023]
Abstract
PURPOSE The sedating effect of first generation H(1)-antihistamines has been associated with their ability to penetrate the blood-brain barrier (BBB) and lack of efflux by P-glycoprotein (Pgp). Second generation H(1)-antihistamines are relatively free of sedation and their limited brain penetration has been suggested to arise from Pgp-mediated efflux. The objective of this work was to evaluate the role of Pgp in brain penetration of first and second generation antihistamines. METHODS Potential of antihistamines to be Pgp substrates was tested in vitro using Madin Darby canine kidney cells transfected with human Pgp. The role of Pgp in limiting brain penetration of antihistamines was tested by using the in situ brain perfusion technique. RESULTS Majority of antihistamines were Pgp substrates in vitro. Following in situ brain perfusion, the first generation antihistamines substantially penetrated into rat brain independently from Pgp function. The second generation antihistamines terfenadine and loratadine, achieved substantial brain penetration, which was further enhanced by Pgp inhibition by cyclosporin A (CSA). In contrast, fexofenadine and cetirizine, penetrated brain poorly regardless of CSA administration. CONCLUSIONS Antihistamines greatly differ in their ability to cross the BBB as well as in the role of Pgp in limiting their transport into the CNS in vivo.
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Affiliation(s)
- Tanja Obradovic
- Absorption Systems, Oaklands Corporate Center, 440 Creamery Way, Suite 300, Exton, Pennslyvania 19341-2554, USA.
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Anderson BD, May MJ, Jordan S, Song L, Roberts MJ, Leggas M. Dependence of nelfinavir brain uptake on dose and tissue concentrations of the selective P-glycoprotein inhibitor zosuquidar in rats. Drug Metab Dispos 2006; 34:653-9. [PMID: 16434546 DOI: 10.1124/dmd.105.006536] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Most reverse transcriptase and protease inhibitors used in highly active antiretroviral therapy for treating human immunodeficiency virus (HIV) infections exhibit poor penetration into the brain, raising the concern that the brain may be a sanctuary site for the development of resistant HIV variants. This study explores the relationship between the dose and plasma and brain concentrations of zosuquidar and the effect of this selective P-glycoprotein inhibitor on central nervous system penetration of the HIV protease inhibitor nelfinavir maintained at steady state by intravenous infusions in rats. Nelfinavir was infused (10 mg/kg/h) for up to 10 h with or without concurrent administration of an intravenous bolus dose of 2, 6, or 20 mg/kg zosuquidar given at 4 h. Brain tissue and plasma were analyzed for both drug concentrations. Brain tissue/plasma nelfinavir concentration ratios (uncorrected for the vascular contribution) increased nonlinearly with zosuquidar dose from 0.06 +/- 0.03 in the absence of zosuquidar and 0.09 +/- 0.02 between 2 and 6 h after 2 mg/kg zosuquidar to 0.85 +/- 0.19 after 6 mg/kg and 1.58 +/- 0.67 after 20 mg/kg zosuquidar. Zosuquidar brain tissue/plasma concentration ratios exhibited a similar abrupt increase from 2.8 +/- 0.3 after a 2 mg/kg dose to approximately 15 after the 6 and 20 mg/kg doses. The apparent threshold in the plasma concentration of zosuquidar necessary to produce significant enhancement in brain uptake of nelfinavir appears to be close to the plasma concentrations associated with the maximum tolerated dose reported in the literature after repeated dosing of zosuquidar in patients.
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Affiliation(s)
- Bradley D Anderson
- University of Kentucky, Department of Pharmaceutical Sciences, ASTeCC Bldg, Room A323A, Lexington, KY 40506-0286, USA.
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