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Zhou X, Lyu J, Sun L, Dong J, Xu H. Metabolic programming of Rhododendron chrysanthum leaves following exposure to UVB irradiation. FUNCTIONAL PLANT BIOLOGY : FPB 2021; 48:1175-1185. [PMID: 34600596 DOI: 10.1071/fp20386] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 08/07/2021] [Indexed: 06/13/2023]
Abstract
Excessive UVB reaching the earth is a cause for concern. To decipher the mechanism concerning UVB resistance of plants, we studied the effects of UVB radiation on photosynthesis and metabolic profiling of Rhododendron chrysanthum Pall. by applying 2.3Wm-2 of UVB radiation for 2days. Results showed that maximum quantum yield of PSII (Fv/Fm) and effective quantum yield of PSII (φPSII) decreased by 7.95% and 8.36%, respectively, following UVB exposure. Twenty five known metabolites were identified as most important by two different methods, including univariate and multivariate statistical analyses. Treatment of R. chrysanthum with UVB increased the abundance of flavonoids, organic acids, and amino acids by 62%, 22%, and 5%, respectively. UVB irradiation also induced about 1.18-fold increase in 11 top-ranked metabolites identified: five organic acids (d-2,3-dihydroxypropanoic acid, maleic acid, glyceric acid, fumaric acid and suberic acid), four amino acids (l-norleucine, 3-oxoalanine, l-serine and glycine), and two fatty acids (pelargonic acid and myristoleic acid). In addition, UVB irradiation increased the intermediate products of arginine biosynthesis and the TCA cycle. Taken together, the accumulation of flavonoids, organic acids, amino acids and fatty acids, accompanied by enhancement of TCA cycle and arginine biosynthesis, may protect R. chrysanthum plants against UVB deleterious effects.
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Affiliation(s)
- Xiaofu Zhou
- Faculty of Jilin Provincial Key Laboratory of Plant Spectral Regions Science and Green Production, Jilin Normal University, Siping 136000, China
| | - Jie Lyu
- Faculty of Biological Science and Technology, Baotou Teachers' College, Baotou 014030, China
| | - Li Sun
- Faculty of Siping Central People's Hospital, Siping 136000, China
| | - Jiawei Dong
- Faculty of Jilin Provincial Key Laboratory of Plant Spectral Regions Science and Green Production, Jilin Normal University, Siping 136000, China
| | - Hongwei Xu
- Faculty of Jilin Provincial Key Laboratory of Plant Spectral Regions Science and Green Production, Jilin Normal University, Siping 136000, China
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Abduljalil K, Pansari A, Jamei M. Prediction of maternal pharmacokinetics using physiologically based pharmacokinetic models: assessing the impact of the longitudinal changes in the activity of CYP1A2, CYP2D6 and CYP3A4 enzymes during pregnancy. J Pharmacokinet Pharmacodyn 2020; 47:361-383. [DOI: 10.1007/s10928-020-09711-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 08/11/2020] [Indexed: 12/19/2022]
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Senescence and the Impact on Biodistribution of Different Nanosystems: the Discrepancy on Tissue Deposition of Graphene Quantum Dots, Polycaprolactone Nanoparticle and Magnetic Mesoporous Silica Nanoparticles in Young and Elder Animals. Pharm Res 2020; 37:40. [PMID: 31970499 DOI: 10.1007/s11095-019-2754-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 12/30/2019] [Indexed: 12/16/2022]
Abstract
PURPOSES Senescence is an inevitable and irreversible process, which may lead to loss in muscle and bone density, decline in brain volume and loss in renal clearance. Although aging is a well-known process, few studies on the consumption of nanodrugs by elderly people were performed. METHODS We evaluated three different nanosystems: i) carbon based nanosystem (Graphene Quantum Dots, GQD), ii) polymeric nanoparticles and mesoporous silica (magnetic core mesoporous silica, MMSN). In previous studies, our group has already characterized GQD and MMSN nanoparticles by dynamic light scattering analysis, atomic force microscopy, transmission electron microscopy, X-ray diffraction, Raman analysis, fluorescence and absorbance. The polymeric nanoparticle has been characterized by AFM and DLS. All the nanosystems were radiolabeled with 99 m-Tc by. The in vivo biodistribution/tissue deposition analysis evaluation was done using elder (PN270) and young (PN90) mice injected with radioactive nanosystems. RESULTS The nanosystems used in this study were well-formed as the radiolabeling processes were stable. Biodistribution analysis showed that there is a decrease in the uptake of the nanoparticles in elder mice when compared to young mice, showing that is necessary to increase the initial dose in elder people to achieve the same concentration when compared to young animals. CONCLUSION The discrepancy on tissue distribution of nanosystems between young and elder individuals must be monitored, as the therapeutic effect will be different in the groups. Noteworthy, this data is an alarm that some specific conditions must be evaluated before commercialization of nano-drugs. Graphical Abstract Changes between younger and elderly individuals are undoubtedly, especially in drug tissue deposition, biodistribution and pharmacokinetics. The same thought should be applied to nanoparticles. A comprehensive analysis on how age discrepancy change the biological behavior of nanoparticles has been performed.
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Couto N, Al-Majdoub ZM, Achour B, Wright PC, Rostami-Hodjegan A, Barber J. Quantification of Proteins Involved in Drug Metabolism and Disposition in the Human Liver Using Label-Free Global Proteomics. Mol Pharm 2019; 16:632-647. [DOI: 10.1021/acs.molpharmaceut.8b00941] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Narciso Couto
- Centre for Applied Pharmacokinetic Research, University of Manchester, Stopford Building, Oxford Road, Manchester M13 9PT, U.K
- Department of Chemical and Biological Engineering, ChELSI Institute (Chemical Engineering at the Life Science Interface), University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield S1 3JD, U.K
| | - Zubida M. Al-Majdoub
- Centre for Applied Pharmacokinetic Research, University of Manchester, Stopford Building, Oxford Road, Manchester M13 9PT, U.K
| | - Brahim Achour
- Centre for Applied Pharmacokinetic Research, University of Manchester, Stopford Building, Oxford Road, Manchester M13 9PT, U.K
| | - Phillip C. Wright
- Department of Chemical and Biological Engineering, ChELSI Institute (Chemical Engineering at the Life Science Interface), University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield S1 3JD, U.K
| | - Amin Rostami-Hodjegan
- Centre for Applied Pharmacokinetic Research, University of Manchester, Stopford Building, Oxford Road, Manchester M13 9PT, U.K
- Simcyp Ltd. (a Certara company), 1 Concourse Way, Sheffield S1 2BJ, U.K
| | - Jill Barber
- Centre for Applied Pharmacokinetic Research, University of Manchester, Stopford Building, Oxford Road, Manchester M13 9PT, U.K
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Rostami-Hodjegan A. Reverse Translation in PBPK and QSP: Going Backwards in Order to Go Forward With Confidence. Clin Pharmacol Ther 2017; 103:224-232. [PMID: 29023678 PMCID: PMC5813098 DOI: 10.1002/cpt.904] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 10/02/2017] [Accepted: 10/06/2017] [Indexed: 02/06/2023]
Abstract
Significant events have taken place shaping the recent industrialization of physiologically based pharmacokinetic in vitro-in vivo extrapolation (PBPK-IVIVE) use in drug development. Due to our knowledge gaps about drug-independent systems parameters, there are limitations in the use of purely IVIVE-based (bottom-up) approaches. This has encouraged combining the classical data analysis (top-down) with PBPK-IVIVE-linked models in order to optimize model parameters by taking advantage of observed clinical data. This concept, when initiated after clinical observations, can be viewed as "reverse translation," since it refers back to available systems information preclinical data before trying to describe the observations. This review demonstrates the advantages of such strategies in filling knowledge gaps and discusses the perceived hurdles in widening applications. It is paramount that no clinical data are assessed on their own, but in conjunction with other studies for that drug in different populations and/or other similar drugs in the same population.
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Affiliation(s)
- Amin Rostami-Hodjegan
- Centre for Applied Pharmacokinetics Research (CAPKR), University of Manchester, Manchester, UK.,Certara, Blades Enterprise Centre, Sheffield, UK
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Marsousi N, Desmeules JA, Rudaz S, Daali Y. Usefulness of PBPK Modeling in Incorporation of Clinical Conditions in Personalized Medicine. J Pharm Sci 2017; 106:2380-2391. [DOI: 10.1016/j.xphs.2017.04.035] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Revised: 04/06/2017] [Accepted: 04/07/2017] [Indexed: 12/14/2022]
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Neves DV, Lanchote VL, Moysés Neto M, Cardeal da Costa JA, Vieira CP, Coelho EB. Influence of chronic kidney disease and haemodialysis treatment on pharmacokinetics of nebivolol enantiomers. Br J Clin Pharmacol 2016; 82:83-91. [PMID: 26914703 DOI: 10.1111/bcp.12917] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 01/19/2016] [Accepted: 02/18/2016] [Indexed: 11/29/2022] Open
Abstract
AIM The present study evaluated the pharmacodynamics and pharmacokinetics of nebivolol enantiomers in patients with chronic kidney disease (CKD) and in patients undergoing haemodialysis. METHODS Forty-three adult patients were distributed into three groups: healthy volunteers and hypertensive patients with normal kidney function (n = 22); patients with stage 3 and 4 CKD (n = 11); and patients with stage 5 CKD undergoing haemodialysis (n = 10). The subjects received a single oral dose of 10 mg racemic nebivolol. Serial blood samples were collected up to 48 h after administration of the drug and heart rate variation was measured over the same interval during the isometric handgrip test. The nebivolol enantiomers in plasma were analysed by liquid chromatography-tandem mass spectrometry. RESULTS The pharmacokinetics of nebivolol is enantioselective, with a greater plasma proportion of l-nebivolol. CKD increased the area under the concentration-time curve (AUC) of l-nebivolol (6.83 ng.h ml(-1) vs. 9.94 ng.h ml(-1) ) and d-nebivolol (4.15 ng.h ml(-1) vs. 7.30 ng.h ml(-1) ) when compared with the control group. However, the AUC values of l-nebivolol (6.41 ng.h ml(-1) ) and d-nebivolol (4.95 ng.h ml(-1) ) did not differ between the haemodialysis and control groups. The administration of a single dose of 10 mg nebivolol did not alter the heart rate variation induced by isometric exercise in the investigated patients. CONCLUSIONS Stage 3 and 4 CKD increases the plasma concentrations of both nebivolol enantiomers, while haemodialysis restores the pharmacokinetic parameters to values similar to those observed in the control group. No significant difference in heart rate variation induced by isometric exercise was observed between the investigated groups after the administration of a single oral dose of 10 mg nebivolol.
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Affiliation(s)
- Daniel V Neves
- Department of Clinical Analysis, Food Science and Toxicology, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Vera L Lanchote
- Department of Clinical Analysis, Food Science and Toxicology, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Miguel Moysés Neto
- Department of Internal Medicine, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - José A Cardeal da Costa
- Department of Internal Medicine, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Carolina P Vieira
- Department of Clinical Analysis, Food Science and Toxicology, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Eduardo B Coelho
- Department of Internal Medicine, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
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Lalande L, Charpiat B, Leboucher G, Tod M. Consequences of renal failure on non-renal clearance of drugs. Clin Pharmacokinet 2015; 53:521-32. [PMID: 24861189 DOI: 10.1007/s40262-014-0146-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Kidney disease not only alters the renal elimination but also the non-renal disposition of drugs that are metabolized by the liver. Indeed, modifications in the expression and activity of intestinal and hepatic drug metabolism enzymes and uptake and efflux transporters have been reported. Accumulated uremic toxins, inflammatory cytokines, and parathyroid hormones may modulate these proteins either directly or by inhibiting gene expression. This can lead to important unintended variations in exposure and response when drugs are administered without dose adjustment for reduced renal function. This review summarizes our current understanding of non-renal clearance in circumstances of chronic and acute renal failure with experimental but also clinical studies. It also evaluates the clinical impact on drug disposition. Predicting the extent of the drug disposition modification is difficult first because of the complex interplay between metabolic enzymes and transport proteins but also because of the differential effects in the different organs (liver, intestines). Recommendations of the US FDA are presented as they may be potentially helpful tools to predict these modifications when no specific pharmacokinetic studies are available.
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Affiliation(s)
- Laure Lalande
- Department of Pharmacy, Groupement Hospitalier Nord, Hospices Civils de Lyon, 103 Grande Rue de la Croix Rousse, 69317, Lyon Cedex 04, France,
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Achour B, Barber J, Rostami-Hodjegan A. Expression of Hepatic Drug-Metabolizing Cytochrome P450 Enzymes and Their Intercorrelations: A Meta-Analysis. Drug Metab Dispos 2014; 42:1349-56. [DOI: 10.1124/dmd.114.058834] [Citation(s) in RCA: 150] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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Achour B, Russell MR, Barber J, Rostami-Hodjegan A. Simultaneous Quantification of the Abundance of Several Cytochrome P450 and Uridine 5′-Diphospho-Glucuronosyltransferase Enzymes in Human Liver Microsomes Using Multiplexed Targeted Proteomics. Drug Metab Dispos 2014; 42:500-10. [DOI: 10.1124/dmd.113.055632] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Polasek TM, Patel F, Jensen BP, Sorich MJ, Wiese MD, Doogue MP. Predicted metabolic drug clearance with increasing adult age. Br J Clin Pharmacol 2013; 75:1019-28. [PMID: 22924488 PMCID: PMC3612720 DOI: 10.1111/j.1365-2125.2012.04446.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Accepted: 08/16/2012] [Indexed: 11/28/2022] Open
Abstract
AIM To determine the effect of increasing adult age on predicted metabolic drug clearance. METHOD Predicted metabolic drug clearances (CLPT ) were determined using in vitro-in vivo extrapolation coupled with physiological-based pharmacokinetic modelling and simulation (IVIVE-PBPK) in Simcyp®. Simulations were conducted using CYP-selective 'probe' drugs with subjects in 5 year age groups (20-25 to 90-95 years). CLPT values were compared with human pharmacokinetic data stratified according to age (young = 20-40 years and elderly = 65-85 years) and gender. Age-related changes in the physiological parameters used for IVIVE of CLPT were described. RESULTS Predicted metabolic drug clearances decreased with increasing adult age to approximately 65-70 years: caffeine from 1.5 to 1.0 ml min(-1) kg(-1) (a 33% decrease), S-warfarin from 0.100 to 0.064 ml min(-1) kg(-1) (36%), S-mephenytoin from 4.1 to 2.5 ml min(-1) kg(-1) (39%), desipramine from 10.6 to 7.3 ml min(-1) kg(-1) (31%) and midazolam from 5.4 to 3.9 ml min(-1) kg(-1) (27%). Except for S-mephenytoin, predictions were within 3.5-fold of clearances from clinical studies when stratified by age and gender. A trend towards higher CLPT was observed in females, but this was only statistically significant in larger virtual trials. Physiological parameters that determine CLPT decreased with increasing adult age: mean microsomal protein g(-1) of liver, liver weight, hepatic blood flow and human serum albumin concentration. CONCLUSION Decreased metabolic clearance in the elderly was predicted by Simcyp® and was generally consistent with limited clinical data for four out of five drugs studied and the broader literature for drugs metabolized by CYP enzymes. IVIVE-PBPK may be increasingly useful in predicting metabolic drug clearance in the elderly.
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Affiliation(s)
- Thomas M Polasek
- Department of Clinical Pharmacology, Flinders University and Flinders Medical Centre, Adelaide, SA, Australia.
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Developmental Changes in the Expression and Function of Cytochrome P450 3A Isoforms: Evidence from In Vitro and In Vivo Investigations. Clin Pharmacokinet 2013; 52:333-45. [DOI: 10.1007/s40262-013-0041-1] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Ke AB, Nallani SC, Zhao P, Rostami-Hodjegan A, Isoherranen N, Unadkat JD. A physiologically based pharmacokinetic model to predict disposition of CYP2D6 and CYP1A2 metabolized drugs in pregnant women. Drug Metab Dispos 2013; 41:801-13. [PMID: 23355638 DOI: 10.1124/dmd.112.050161] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Conducting pharmacokinetic (PK) studies in pregnant women is challenging. Therefore, we asked if a physiologically based pharmacokinetic (PBPK) model could be used to evaluate different dosing regimens for pregnant women. We refined and verified our previously published pregnancy PBPK model by incorporating cytochrome P450 CYP1A2 suppression (based on caffeine PK) and CYP2D6 induction (based on metoprolol PK) into the model. This model accounts for gestational age-dependent changes in maternal physiology and hepatic CYP3A activity. For verification, the disposition of CYP1A2-metabolized drug theophylline (THEO) and CYP2D6-metabolized drugs paroxetine (PAR), dextromethorphan (DEX), and clonidine (CLO) during pregnancy was predicted. Our PBPK model successfully predicted THEO disposition during the third trimester (T3). Predicted mean postpartum to third trimester (PP:T3) ratios of THEO area under the curve (AUC), maximum plasma concentration, and minimum plasma concentration were 0.76, 0.95, and 0.66 versus observed values 0.75, 0.89, and 0.72, respectively. The predicted mean PAR steady-state plasma concentration (Css) ratio (PP:T3) was 7.1 versus the observed value 3.7. Predicted mean DEX urinary ratio (UR) (PP:T3) was 2.9 versus the observed value 1.9. Predicted mean CLO AUC ratio (PP:T3) was 2.2 versus the observed value 1.7. Sensitivity analysis suggested that a 100% induction of CYP2D6 during T3 was required to recover the observed PP:T3 ratios of PAR Css, DEX UR, and CLO AUC. Based on these data, it is prudent to conclude that the magnitude of hepatic CYP2D6 induction during T3 ranges from 100 to 200%. Our PBPK model can predict the disposition of CYP1A2, 2D6, and 3A drugs during pregnancy.
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Affiliation(s)
- Alice Ban Ke
- Department of Pharmaceutics, University of Washington, Box 357610, Seattle, WA 98195, USA
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A PBPK Model to Predict Disposition of CYP3A-Metabolized Drugs in Pregnant Women: Verification and Discerning the Site of CYP3A Induction. CPT-PHARMACOMETRICS & SYSTEMS PHARMACOLOGY 2012; 1:e3. [PMID: 23835883 PMCID: PMC3606941 DOI: 10.1038/psp.2012.2] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Besides logistical and ethical concerns, evaluation of safety and efficacy of medications in pregnant women is complicated by marked changes in pharmacokinetics (PK) of drugs. For example, CYP3A activity is induced during the third trimester (T3). We explored whether a previously published physiologically based pharmacokinetic (PBPK) model could quantitatively predict PK profiles of CYP3A-metabolized drugs during T3, and discern the site of CYP3A induction (i.e., liver, intestine, or both). The model accounted for gestational age-dependent changes in maternal physiological function and hepatic CYP3A activity. For model verification, mean plasma area under the curve (AUC), peak plasma concentration (Cmax), and trough plasma concentration (Cmin) of midazolam (MDZ), nifedipine (NIF), and indinavir (IDV) were predicted and compared with published studies. The PBPK model successfully predicted MDZ, NIF, and IDV disposition during T3. A sensitivity analysis suggested that CYP3A induction in T3 is most likely hepatic and not intestinal. Our PBPK model is a useful tool to evaluate different dosing regimens during T3 for drugs cleared primarily via CYP3A metabolism.
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Abduljalil K, Furness P, Johnson TN, Rostami-Hodjegan A, Soltani H. Anatomical, Physiological and Metabolic Changes with Gestational Age during Normal Pregnancy. Clin Pharmacokinet 2012; 51:365-96. [DOI: 10.2165/11597440-000000000-00000] [Citation(s) in RCA: 220] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Plowchalk DR, Rowland Yeo K. Prediction of drug clearance in a smoking population: modeling the impact of variable cigarette consumption on the induction of CYP1A2. Eur J Clin Pharmacol 2012; 68:951-60. [PMID: 22258279 DOI: 10.1007/s00228-011-1189-y] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Accepted: 11/24/2011] [Indexed: 11/26/2022]
Abstract
PURPOSE To derive estimates of CYP1A2 abundance as a function of daily cigarette consumption and use these values to predict the clearances of CYP1A2 substrates in smokers. METHODS Smoking-induced changes in hepatic CYP1A2 abundance were extrapolated from reported in vivo caffeine clearance data for sub-groups of a smoking population that were categorized according to their daily cigarette consumption. These abundance values together with in vitro-in vivo extrapolation (IVIVE) within the Simcyp population-based Simulator were used to predict the clearances of caffeine, theophylline, and clozapine in smokers. The model was used subsequently to predict differences in oral clearance between smoker and non-smoker cohorts in a Phase 1 clinical trial involving PF-2400013, a drug metabolized by CYP1A2. RESULTS Estimated hepatic CYP1A2 abundance values were 52, 64, 79, 90, and 94 pmol/mg microsomal protein for subjects smoking 0, 1-5, 6-10, 11-20, and >20 cigarettes/day respectively. Predicted -fold increases in oral clearance of caffeine, theophylline and clozapine in smokers relative to non-smokers were consistent with observed data. The validated model was able to recover the smoking-induced increase in oral clearance of PF-2400013; predicted and observed mean (CV%) values in male nonsmokers and smokers were 90 L/h (40%) and 141 L/h (34%) respectively, and 100 L/h (58%) and 131 L/h (33%) respectively. CONCLUSIONS This study demonstrates that it may be possible to predict the clearance of CYP1A2 substrates in smoking populations using quantitative estimates of CYP1A2 abundance based on daily cigarette consumption in conjunction with an IVIVE approach.
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Affiliation(s)
- David R Plowchalk
- Clinical Pharmacology, Primary Care BU, Pfizer Inc., 445 Eastern Point Road, Groton, CT 06340, USA.
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Johnson TN, Boussery K, Rowland-Yeo K, Tucker GT, Rostami-Hodjegan A. A semi-mechanistic model to predict the effects of liver cirrhosis on drug clearance. Clin Pharmacokinet 2010; 49:189-206. [PMID: 20170207 DOI: 10.2165/11318160-000000000-00000] [Citation(s) in RCA: 161] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND AND OBJECTIVE Liver cirrhosis is characterized by a decrease in functional hepatocytes, lowered circulating levels of plasma proteins and alterations in blood flow due to the development of portacaval shunts. Depending on the interplay between these parameters and the characteristics of an administered drug, varying degrees of impaired systemic clearance and first-pass metabolism are anticipated. The Simcyp Population-based ADME Simulator has already been used successfully to incorporate genetic, physiological and demographic attributes of certain subgroups within healthy populations into in vitro-in vivo extrapolation (IVIVE) of xenobiotic clearance. The objective of this study was to extend population models to predict systemic and oral drug clearance in relation to the severity of liver cirrhosis. METHODS Information on demographics, changes in hepatic blood flow, cytochrome P450 enzymes, liver size, plasma protein binding and renal function was incorporated into three separate population libraries. The latter corresponded to Child-Pugh scores A (mild), B (moderate) and C (severe) liver cirrhosis. These libraries, together with mechanistic IVIVE within the Simcyp Simulator, were used to predict the clearance of intravenous and oral midazolam, oral caffeine, intravenous and oral theophylline, intravenous and oral metoprolol, oral nifedipine, oral quinidine, oral diclofenac, oral sildenafil, and intravenous and oral omeprazole. The simulated patients matched the clinical studies as closely as possible with regard to demographics and Child-Pugh scores. Predicted clearance values in both healthy control and liver cirrhosis populations were compared with observed values, as were the fold increases in clearance values between these populations. RESULTS There was good agreement (lack of statistically significant difference, two-tailed paired t-test) between observed and predicted clearance ratios, with the exception of those for two studies of intravenous omeprazole. Predicted clearance ratios were within 0.8- to 1.25-fold of observed ratios in 65% of cases (range 0.34- to 2.5-fold). CONCLUSION The various drugs that were studied showed different changes in clearance in relation to disease severity, and a 'one size fits all' solution does not exist without considering the multiple sources of the changes. Predictions of the effects of liver cirrhosis on drug clearance are of potential value in the design of clinical studies during drug development and, clinically, in the assessment of likely dosage adjustment.
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Turpeinen M, Koivuviita N, Tolonen A, Reponen P, Lundgren S, Miettunen J, Metsärinne K, Rane A, Pelkonen O, Laine K. Effect of renal impairment on the pharmacokinetics of bupropion and its metabolites. Br J Clin Pharmacol 2007; 64:165-73. [PMID: 17335546 PMCID: PMC2000634 DOI: 10.1111/j.1365-2125.2007.02866.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
AIMS To investigate the effect of kidney disease on bupropion pharmacokinetics and on cytochrome P450 (CYP) 2B6 activity as measured by bupropion hydroxylation. METHODS In an open parallel group study, 17 healthy, nonsmoking subjects and 10 patients with impaired kidney function received a single 150 mg oral dose of sustained release bupropion. Plasma concentrations of bupropion and its metabolites were measured for up to 72 h. Subjects were genotyped for the CYP2B6 SNPs 1459 C>T, 785 A>G and 516 G>T. RESULTS Bupropion AUC was 126% higher (P < 0.0001, 95% CI +72%, +180%), C(max) 86% higher (P = 0.001, 95% CI +40%, +131%), CL/F 63% lower (P = 0.001, 95% CI -29%, -96%), and t(1/2) 140% longer (P = 0.001, 95% CI +76%, +204%) in renally impaired patients. However, only minor changes were detected in the concentrations of the metabolites. In renally impaired subjects the hydroxybupropion : bupropion AUC ratio was decreased by 66% (P = < 0.0001, 95% CI -19%, -114%) and the hydrobupropion : bupropion AUC ratio by 69% (P = 0.001, 95% CI +8%, -146%) compared with controls. CONCLUSIONS The CL/F of bupropion was significantly lower in subjects with renal impairment. Because the principal metabolites of bupropion possess similar pharmacological activity to the parent compound, dosage recommendations for patients with renal impairment cannot be given. A direct effect of renal impairment on CYP2B6 activity could not be demonstrated by the present study design.
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Affiliation(s)
- Miia Turpeinen
- Department of Pharmacology and Toxicology, University of Oulu, Oulu, Finland.
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Frank D, Jaehde U, Fuhr U. Evaluation of probe drugs and pharmacokinetic metrics for CYP2D6 phenotyping. Eur J Clin Pharmacol 2007; 63:321-33. [PMID: 17273835 DOI: 10.1007/s00228-006-0250-8] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2006] [Accepted: 12/07/2006] [Indexed: 11/27/2022]
Abstract
INTRODUCTION Cytochrome P450 2D6 (CYP2D6) is one of the most important enzymes catalyzing biotransformation of xenobiotics in the human liver. This enzyme's activity shows a high degree of interindividual variability caused in part by its genetic polymorphism, the so-called debrisoquine/sparteine polymorphism. The genetic component influencing CYP2D6 activity can be determined by genotyping. However, genotyping alone is not sufficient to accurately predict an individual's actual CYP2D6 activity, as this is also influenced by other factors. For the determination of the exact actual enzymatic activity ("phenotyping"), adequate probe drugs have to be administered prior to measurements of these compounds and/or their metabolites in body fluids. PROBE DRUGS: Debrisoquine, sparteine, metoprolol or dextromethorphan represent well-established probe drugs while tramadol has been recently investigated for this purpose. The enzymatic activity is reflected by various pharmacokinetic metrics such as the partial clearance of a parent compound to the respective CYP2D6-mediated metabolite or metabolic ratios. Appropriate metrics need to fulfill pre-defined validation criteria. METHODS In this review, we have compiled a list of such criteria useful to select the best metrics to reflect CYP2D6 activity. A comprehensive Medline search for reports on CYP2D6 phenotyping trials with the above mentioned probe drugs was carried out. CONCLUSION Application of the validation criteria suggests that dextromethorphan and debrisoquine are the best CYP2D6 phenotyping drugs, with debrisoquine having the problem of very limited availability as a therapeutic drug. However, the assessment of the best dextromethorphan CYP2D6 phenotyping metric/procedure is still ongoing.
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Affiliation(s)
- D Frank
- Department of Pharmacology, Clinical Pharmacology, University of Cologne, Gleueler Strasse 24, 50931, Köln, Germany.
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Ismail R, Teh LK. The relevance of CYP2D6 genetic polymorphism on chronic metoprolol therapy in cardiovascular patients. J Clin Pharm Ther 2006; 31:99-109. [PMID: 16476126 DOI: 10.1111/j.1365-2710.2006.00699.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND AND OBJECTIVE CYP2D6 polymorphisms are well described in normal populations but there are few data on its clinical significance. We therefore investigated the influence of CYP2D6 polymorphism on steady-state plasma concentrations and apparent oral clearance of metoprolol in patients with cardiovascular diseases. METHODS Ninety-one patients on metoprolol were recruited. Plasma concentrations of metoprolol and alpha-hydroxy metoprolol were measured at 4-h post-dose. CYP2D6 genotyping (*1, *3, *4, *5, *9, *8, *10, *17 and duplication) were performed on the DNA extracted. Ratio of plasma concentrations of metoprolol and alpha-hydroxy metoprolol and the apparent oral clearance of metoprolol were calculated. The influences of CYP2D6 genotypes were investigated. RESULTS A 100-fold variation was noted for both plasma concentrations of metoprolol and alpha-hydroxy metoprolol. There was a weak correlation between the total daily doses and plasma concentrations of both. Plasma concentrations were found to be higher in patients with genotypes that predicted lower enzyme activity. One patient homozygous for CYP2D6*4 had the highest metoprolol concentration per unit dose. With an antimode of 10. Two patients were identified as poor metabolizers (PMs) (2.1%; 95% CI: 2.9). The PMs who had a plasma metabolic ratio (pMR) of 37.8 was homozygous CYP2D6*4 whereas the other with pMR 14.5 was genotyped CYP2D6 *4/*10. There was a 36-fold difference between the highest and lowest clearance values. Large overlaps in the clearance values were noted between most of the genotypes. CONCLUSIONS Our data suggest that pharmacogenetic measures could be used to design a more individualized metoprolol dosage regimen for patients.
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Affiliation(s)
- R Ismail
- Institute for Research in Molecular Medicine, Universiti Sains Malaysia, Health Campus, 16150 Kubang Kerian, Malaysia.
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Srinivas NR. Drug disposition of chiral and achiral drug substrates metabolized by cytochrome P450 2D6 isozyme: case studies, analytical perspectives and developmental implications. Biomed Chromatogr 2006; 20:466-91. [PMID: 16779774 DOI: 10.1002/bmc.680] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The concepts of drug development have evolved over the last few decades. Although number of novel chemical entitities belonging to varied classes have made it to the market, the process of drug development is challenging, intertwined as it is with complexities and uncertainities. The intention of this article is to provide a comprehensive review of novel chemical entities (NCEs) that are substrates to cytochrome P450 (CYP) 2D6 isozyme. Topics covered in this review aim: (1) to provide a framework of the importance of CYP2D6 isozyme in the biotransformation of NCEs as stand-alones and/or in conjunction with other CYP isozymes; (2) to provide several case studies of drug disposition of important drug substrates, (3) to cover key analytical perspectives and key assay considerations to assess the role and involvement of CYP2D6, and (4) to elaborate some important considerations from the development point of view. Additionally, wherever applicable, special emphasis is provided on chiral drug substrates in the various subsections of the review.
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Affiliation(s)
- Nuggehally R Srinivas
- Drug Development, Discovery Research, Dr Reddy's Laboratories, Miyapur, Hyderabad, India.
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Michaud J, Dubé P, Naud J, Leblond FA, Desbiens K, Bonnardeaux A, Pichette V. Effects of serum from patients with chronic renal failure on rat hepatic cytochrome P450. Br J Pharmacol 2005; 144:1067-77. [PMID: 15700027 PMCID: PMC1576090 DOI: 10.1038/sj.bjp.0706138] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. In humans, chronic renal failure (CRF) is associated with decreased hepatic drug metabolism, particularly that mediated by the cytochrome P450 (P450). The mechanisms remain poorly understood. The present study aimed to investigate the effects of the serum of patients with CRF on liver P450, and to evaluate whether renal replacement therapies (dialysis or transplantation) impede the inhibition of CRF serum on P450. 2. Rat hepatocytes were incubated for 24 h with serum from patients with severe CRF and from controls to measure (1) P450 level, (2) protein expression and mRNA levels of P450 isoforms and (3) metabolic activities of CYP3A and CYP1A. Similar experiments were performed with serum of patients once on chronic hemodialysis and after kidney transplantation. 3. In rat hepatocytes incubated for 24 h with serum from patients with CRF, P450 level and protein expression, as well as mRNA levels of P450 isoforms (CYP1A2, 2C6, 2C11, 2D1/2D2, 3A2 and 4A1/4A3), were decreased by more than 45% (P<0.001) compared to control serum, while the levels of CYP2E1 were not modified. CYP3A and CYP1A activities were decreased by 51 and 59% (P<0.001), respectively. The inhibitory effect of serum obtained from patients before first dialysis was similar after 1 or 6 months on chronic hemodialysis but was lost after successful kidney transplantation. In CRF serum, the fraction containing proteins between 10 and 15 kDa decreases P450. 4. Human uremic serum contains mediator(s) that decreases rat hepatic P450 activity and expression secondary to reduced gene expression. The inhibitory effect of serum persists even after initiation of dialysis, but disappears after normalization of renal function following kidney transplantation.
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Affiliation(s)
- Josée Michaud
- Service de néphrologie et Centre de recherche Guy-Bernier, Hôpital Maisonneuve-Rosemont, Faculté de Médecine, Université de Montréal, 5415 boul.de l'Assomption, Montreal, Québec, Canada H1T 2H4
| | - Pierre Dubé
- Service de néphrologie et Centre de recherche Guy-Bernier, Hôpital Maisonneuve-Rosemont, Faculté de Médecine, Université de Montréal, 5415 boul.de l'Assomption, Montreal, Québec, Canada H1T 2H4
| | - Judith Naud
- Service de néphrologie et Centre de recherche Guy-Bernier, Hôpital Maisonneuve-Rosemont, Faculté de Médecine, Université de Montréal, 5415 boul.de l'Assomption, Montreal, Québec, Canada H1T 2H4
| | - Francois A Leblond
- Service de néphrologie et Centre de recherche Guy-Bernier, Hôpital Maisonneuve-Rosemont, Faculté de Médecine, Université de Montréal, 5415 boul.de l'Assomption, Montreal, Québec, Canada H1T 2H4
| | - Karine Desbiens
- Service de néphrologie et Centre de recherche Guy-Bernier, Hôpital Maisonneuve-Rosemont, Faculté de Médecine, Université de Montréal, 5415 boul.de l'Assomption, Montreal, Québec, Canada H1T 2H4
| | - Alain Bonnardeaux
- Service de néphrologie et Centre de recherche Guy-Bernier, Hôpital Maisonneuve-Rosemont, Faculté de Médecine, Université de Montréal, 5415 boul.de l'Assomption, Montreal, Québec, Canada H1T 2H4
| | - Vincent Pichette
- Service de néphrologie et Centre de recherche Guy-Bernier, Hôpital Maisonneuve-Rosemont, Faculté de Médecine, Université de Montréal, 5415 boul.de l'Assomption, Montreal, Québec, Canada H1T 2H4
- Author for correspondence:
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Shah RR. Mechanistic basis of adverse drugreactions: the perils of inappropriate dose schedules. Expert Opin Drug Saf 2005; 4:103-28. [PMID: 15709902 DOI: 10.1517/14740338.4.1.103] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Adverse drug reactions (ADRs) have long been recognised as a significant cause of morbidity and mortality. They account for a substantial number of clinical consultations, hospital admissions and extended duration of in-patient stay as well as mortality. By far the most common ADRs are the concentration-dependent pharmacological reactions, the majority of which ought to be preventable. As a result of high concentrations of the parent drug and/or its metabolite(s), there is an augmentation of primary pharmacological activity and/or appearance of new and undesirable secondary pharmacological activity. Typically, these high concentrations result from administration of high doses in an attempt to maximise efficacy and/or modulation of the pharmacokinetics of a drug by either genetic or non-genetic factors. High plasma concentrations of parent drug may result from inherited impairment or drug-induced inhibition of its pharmacokinetic disposition. Conversely, inherited overcapacity or drug-induced induction of the metabolism of a drug may result in low concentrations of parent drug and frequently, rapid accumulation of its metabolites. Environmental, dietary and phytochemical factors may also influence the activity of drug metabolising enzymes. As with inherited polymorphisms of acetylation and cytochrome P450-based drug metabolising enzymes, polymorphisms of other conjugation reactions, such as glucuronidation, increasingly appear to be associated with drug toxicity. Diseases of organs involved in elimination of a drug also alter its pharmacokinetics, plasma concentration and, therefore, the profile of its concentration-dependent ADRs. Inherited mutations, concurrently administered drugs or presence of certain diseases may also alter the sensitivity of some pharmacological targets, accounting for a substantial number of ADRs and interactions. When there is enhanced pharmacodynamic sensitivity, plasma drug concentrations that are apparently within the normal 'non-toxic' range give rise to ADRs. Recent advances have also provided important insights into the wider scope of drug-drug interactions. Interactions that occur at P-glycoproteins, drug transporters and efflux pumps, at various transmembrane interfaces such as the gastrointestinal wall, renal tubules, hepatobiliary border and blood-brain barrier, are beginning to explain many non-metabolic interactions. These alter the systemic exposure to drugs and have so far, begun to explain unexpected neurotoxicity and hepatotoxicity. The function of these transporters is also genetically modulated. These advances, together with continued increased awareness and education of prescribers and pharmacists, offer great opportunities for substantially minimising concentration-related ADRs.
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Affiliation(s)
- Rashmi R Shah
- Medicines and Healthcare products Regulatory Agency (MHRA), Market Towers, 1 Nine Elms Lane, Vauxhall, London, SW8 5NQ, UK.
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Ozdemir M, Crewe KH, Tucker GT, Rostami-Hodjegan A. Assessment of in vivo CYP2D6 activity: differential sensitivity of commonly used probes to urine pH. J Clin Pharmacol 2005; 44:1398-404. [PMID: 15545311 DOI: 10.1177/0091270004269582] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Drug/metabolite ratios (MRs) are used as in vivo markers of enzyme activity. The ratios are potentially confounded by the renal clearance of the drug (urine-based MRs) or metabolite (plasma-based MRs). The authors have investigated the relative sensitivity of urinary MR of 3 in vivo probe substrates of CYP2D6 debrisoquine (DB), dextromethorphan (DM), and metoprolol (MP) to changes in urine pH. Three groups of healthy volunteers each comprising 12 individuals were given DB (10 mg), DM (25 mg), or MP (100 mg) on 3 occasions. In 1 study arm, urine was acidified by the oral intake of ammonium chloride; in another, it was alkalinized by intake of sodium bicarbonate; and in the third, urine pH was uncontrolled. Urinary MP/alpha-hydroxy-MP, DM/dextrorphan, and DB/4-hydroxy-DB ratios were calculated. The mean(geo) MR for DB was not significantly different in any of the study arms, whereas those for MP and DM were significantly different under acidified and alkalinized urine conditions compared to uncontrolled urine pH (P < .01) and were correlated with urine pH (P < .001). Without control of urine pH, in vivo estimates of CYP2D6 metabolic activity are likely to be less precise using DM or MP as probe substrates compared to DB. Although this is unlikely to cause any problem in distinguishing the large functional differences in CYP2D6 in poor metabolizer (PM) and extensive metabolizer (EM) phenotypes, this may contribute to difficulties in differentiating in vivo metabolic activity among allelic variants within the overall CYP2D6 EM phenotype using MP or DM. However, because DB is not available in many countries (eg, United States), alternative in vivo markers of CYP2D6 with low sensitivity to urine pH should be sought.
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Affiliation(s)
- Mahmut Ozdemir
- Department of Pharmacology, Faculty of Medicine, Osmangazi University, Eskişehir, Turkey
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Shah RR. Drug development and use in the elderly: search for the right dose and dosing regimen (Parts I and II). Br J Clin Pharmacol 2005; 58:452-69. [PMID: 15521892 PMCID: PMC1884629 DOI: 10.1111/j.1365-2125.2004.02228.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- Rashmi R Shah
- Medicines and Healthcare products Regulatory Agency, Market Towers, 1 Nine Elms Lane, Vauxhall, London, UK.
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Abstract
An increasing number of elderly patients are exposed to cardiovascular drugs for the treatment of acute and/or chronic conditions. This is a result of the progressive aging of the population, a common feature in most industrialised countries, and an improvement in primary and secondary cardiovascular prevention strategies with increased survival rates. Traditionally, most elderly patients receiving cardiovascular drugs had advanced cardiac, liver and kidney disease that significantly influenced drug pharmacokinetic and pharmacodynamic parameters. Currently, however, many patients without significant organ impairment receive cardiovascular therapy for primary or early secondary prevention (i.e. increased vascular risk, asymptomatic left ventricular dysfunction, poststroke phase, type 2 diabetes mellitus), highlighting the need for a better understanding of specific age-related pharmacokinetic and pharmacodynamic effects. A systematic review has been conducted on the specific effects of aging, in the absence of major co-morbidities, on the pharmacokinetic and pharmacodynamic properties of traditional and newer cardiovascular drugs. Currently, the evidence available is poor or nonexisting for several drugs and mainly derived from very small and underpowered studies, thus limiting data interpretation. In particular, there is very little information on patients >80 years of age, thus raising important concerns about the correct use of these drugs in this constantly growing population.
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Affiliation(s)
- Arduino A Mangoni
- Department of Clinical Pharmacology, School of Medicine, Flinders University, Adelaide, South Australia, Australia.
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Mangoni AA, Jackson SHD. Age-related changes in pharmacokinetics and pharmacodynamics: basic principles and practical applications. Br J Clin Pharmacol 2004; 57:6-14. [PMID: 14678335 PMCID: PMC1884408 DOI: 10.1046/j.1365-2125.2003.02007.x] [Citation(s) in RCA: 1030] [Impact Index Per Article: 51.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2002] [Accepted: 02/27/2003] [Indexed: 12/18/2022] Open
Abstract
Advancing age is characterized by impairment in the function of the many regulatory processes that provide functional integration between cells and organs. Therefore, there may be a failure to maintain homeostasis under conditions of physiological stress. The reduced homeostatic ability affects different regulatory systems in different subjects, thus explaining at least partly the increased interindividual variability occurring as people get older. Important pharmacokinetic and pharmacodynamic changes occur with advancing age. Pharmacokinetic changes include a reduction in renal and hepatic clearance and an increase in volume of distribution of lipid soluble drugs (hence prolongation of elimination half-life) whereas pharmacodynamic changes involve altered (usually increased) sensitivity to several classes of drugs such as anticoagulants, cardiovascular and psychotropic drugs. This review focuses on the main age-related physiological changes affecting different organ systems and their implications for pharmacokinetics and pharmacodynamics of drugs.
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Affiliation(s)
- A A Mangoni
- Department of Health Care of the Elderly, Guy's, King's, and St Thomas' School of Medicine, King's College London, London.
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Nolin TD, Frye RF, Matzke GR. Hepatic drug metabolism and transport in patients with kidney disease. Am J Kidney Dis 2003; 42:906-25. [PMID: 14582035 DOI: 10.1016/j.ajkd.2003.07.019] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The disposition of many drugs is altered in patients with acute (AKD) and chronic kidney disease (CKD). A decline in renal clearance of several drugs has been correlated significantly with residual renal function (ie, creatinine clearance) of subjects. Reductions in nonrenal clearance of some compounds also have been reported and associated with clearance of markers of oxidative and/or conjugative metabolism or P-glycoprotein-mediated transport. Although initial accounts of reduced hepatic microsomal cytochrome P-450 (CYP) content and activity in animal models of AKD and CKD were published almost 25 years ago, it is only in the last decade that technical advances in molecular biology and clinical pharmacology have enabled researchers to begin to characterize the phenotypic expression of individual enzymes and, importantly, distinguish the molecular and/or genetic basis for these changes. The selective modulation of hepatic CYP enzyme activity observed in kidney disease is caused, at least in part, by differentially altered expression of several CYP isoforms. This review summarizes data available through June 2003 regarding the effect of AKD and CKD on drug metabolism. Knowledge of the impact and nature of these alterations associated with kidney disease may facilitate the individualization of medication management in this patient population.
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Affiliation(s)
- Thomas D Nolin
- Department of Pharmacy Services and Division of Nephrology and Renal Transplantation, Maine Medical Center, Portland, ME, USA
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Yeh GC, Tao PL, Ho HO, Lee YJ, Chen JYR, Sheu MT. Analysis of pharmacokinetic parameters for assessment of dextromethorphan metabolic phenotypes. J Biomed Sci 2003; 10:552-64. [PMID: 12928596 DOI: 10.1007/bf02256117] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2003] [Accepted: 04/14/2003] [Indexed: 11/28/2022] Open
Abstract
In this study, the metabolic ratios of dextromethorphan to dextrorphan (DM/DX) in plasma were calculated at steady state after administering 2 dosage forms (Medicon) and Detusiv) of DM with different release rates. The urinary metabolic ratio for each subject was also determined based on the total drug concentration in the urine. An analysis of pharmacokinetic parameters for determining the DM metabolic phenotype was conducted. Results demonstrate that double logarithmic correlations between the metabolic ratios based on pharmacokinetic parameters of either AUC(0-tau,ss), C(max,ss), C(min,ss), or C(ave,ss) for Medicon and Detusiv and the urinary metabolic ratios were all significant. Probit plots of the metabolic ratios based on these pharmacokinetic parameters revealed 2 clusters of distribution, representing extensive and intermediate metabolizers. An antimode of 2.0 for total drug based on these pharmacokinetic parameters was determined and correspondingly referred to an antimode of 0.02 for the urinary metabolic ratio to delineate extensive and intermediate metabolizers. This model was also verified to be appropriate when using total plasma concentrations of DM and DX at any time during the period of the dosing interval at steady state to calculate the metabolic ratio for identifying extensive and intermediate metabolizers. Therefore, the metabolic ratio based on the pharmacokinetic parameters of either AUC(0-tau,ss), C(max,ss), C(min,ss), or C(ave,ss) and plasma concentrations of DM and DX in a single blood sample at steady state are proposed as an alternative way to identify phenotypes of CYP2D6.
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Affiliation(s)
- Geng-Chang Yeh
- Department of Pediatrics, Taipei Medical University Hospital, Graduate Institute of Medical Science, College of Medicine, Taipei, Taiwan, ROC
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Moghadamnia AA, Rostami-Hodjegan A, Abdul-Manap R, Wright CE, Morice AH, Tucker GT. Physiologically based modelling of inhibition of metabolism and assessment of the relative potency of drug and metabolite: dextromethorphan vs. dextrorphan using quinidine inhibition. Br J Clin Pharmacol 2003; 56:57-67. [PMID: 12848776 PMCID: PMC1884341 DOI: 10.1046/j.1365-2125.2003.01853.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AIMS To define the relative antitussive effect of dextromethorphan (DEX) and its primary metabolite dextrorphan (DOR) after administration of DEX. METHODS Data were analysed from a double-blind, randomized cross-over study in which 22 subjects received the following oral treatments: (i) placebo; (ii) 30 mg DEX hydro-bromide; (iii) 60 mg DEX hydro-bromide; and (iv) 30 mg DEX hydro-bromide preceded at 1 h by quinidine HCl (50 mg). Cough was elicited using citric acid challenge. Pharmacokinetic data from all non-placebo arms of the study were fitted simultaneously. The parameters were then used as covariates in a link PK-PD model of cough suppression using data from all treatment arms. RESULTS The best-fit PK model assumed two- and one-compartment PK models for DEX and DOR, respectively, and competitive inhibition of DEX metabolism by quinidine. The intrinsic clearance of DEX estimated from the model ranged from 59 to 1536 l x h(-1), which overlapped with that extrapolated from in vitro data (12-261 l x h(-1)) and showed similar variation (26- vs. 21-fold, respectively). The inhibitory effect of quinidine ([I]/Ki) was 19 (95% confidence interval of mean: 18-20) with an estimated average Ki of 0.017 microM. Although DEX and DOR were both active, the potency of the antitussive effect of DOR was 38% that of DEX. A sustained antitussive effect was related to slow removal of DEX/DOR from the effect site (ke0 = 0.07 h(-1)). CONCLUSIONS Physiologically based PK modelling with perturbation of metabolism using an inhibitor allowed evaluation of the antitussive potency of DOR without the need for separate administration of DOR.
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Affiliation(s)
- A A Moghadamnia
- Molecular Pharmacology & Pharmacogenetics, Division of Clinical Sciences (South), University of Sheffield, Royal Hallamshire Hospital, Sheffield, UK
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Abstract
With estimates of the percentage of pharmaceuticals that are subject to metabolism by the cytochrome P-450 enzymes (CYPs) in excess of 80%, the relative activities of these enzymes in various subpopulations and even in individual patients can have important ramifications in matters ranging from dose selection to prediction of toxicity to suitability of a new chemical entity (NCE) for continued drug development. The interindividual variation in CYP activities can be profound, and the differences may be due to environmental/physiologic factors, genetic factors, or both. With regard to the process of drug development, it would be useful to know as early in the development process as possible which CYPs are likely to process a NCE, the likely interindividual variation in the processing of a NCE by CYPs, which CYP activities are likely to be altered by a NCE, and the magnitude by which CYP activity is likely to be altered by a NCE. The latter two, in particular, will be useful in predicting drug interactions between the NCE and currently available drugs. For purposes of establishing treatment regimens that are maximally effective and minimally toxic, it follows that advance knowledge of probable CYP activities could be helpful. To the extent that phenotypic expression of CYP activity corresponds to CYP genotype, it may be possible a priori to design optimized therapeutic regimens for selective CYP substrates based on knowledge of a patient's CYP genotype. Because the expression of CYP activity is determined predominantly by prevailing environmental/physiologic conditions, tailoring drug therapy to meet individual patient needs can require knowledge of a patient's CYP phenotype. Strategies for genotyping and phenotyping CYP-450 activity are discussed with special attention paid to in vivo phenotyping methods.
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Affiliation(s)
- Kenneth A Bachmann
- Department of Pharmacology, the University of Toledo, Toledo, Ohio 43606, USA.
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Lourenço A, Máximo P, Ferreira L, Pereira M. Indolizidine and quinolizidine alkaloids structure and bioactivity. ACTA ACUST UNITED AC 2002. [DOI: 10.1016/s1572-5995(02)80038-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2023]
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Hägg S, Spigset O, Dahlqvist R. Influence of gender and oral contraceptives on CYP2D6 and CYP2C19 activity in healthy volunteers. Br J Clin Pharmacol 2001; 51:169-73. [PMID: 11259990 PMCID: PMC2014435 DOI: 10.1111/j.1365-2125.2001.01328.x] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
AIMS The study was carried out in order to assess the effects of gender and the use of oral contraceptives (OCs) on CYP2D6 and CYP2C19 activities in healthy volunteers. METHODS Six hundred and eleven Caucasian volunteers (330 males and 281 females; age range 18-49 years) were phenotyped with respect to CYP2D6 and CYP2C19 by means of the probe drugs dextromethorphan and mephenytoin, respectively. Extensive metabolisers were selected for this study. RESULTS The median dextromethorphan/dextrorphan metabolic ratio in non-OC using females was significantly lower than in males (0.067 vs 0.080; P = 0.033) (mean difference in ln dextromethorphan/dextrorphan metabolic ratio 0.023, 95% CI 0.03-0.43). For the mephenytoin S/R ratio, no such difference was observed. However, OC using females had a significantly higher median mephenytoin S/R ratio than non-OC using females (0.230 vs 0.090; P < 0.001) (mean difference in ln mephenytoin S/R ratio 0.082, 95% CI 0.60-1.04). Moreover, females using combined OCs had a significantly higher median ratio than females using OCs with progestins only (median 0.258 vs 0.135; P = 0.008) (mean difference in ln mephenytoin S/R ratio 0.82, 95% CI 0.21-1.34). CONCLUSIONS Given certain assumptions, the study indicates that females in the fertile age have a slightly higher CYP2D6 activity compared with males. There was no evidence of a gender difference in CYP2C19 activity. The use of combined OCs reduces the activity of CYP2C19, an effect that seems to be related to the ethinyloestradiol component.
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Affiliation(s)
- S Hägg
- Division of Clinical Pharmacology, Norrland University Hospital, Umeå, Sweden
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Labbé L, Sirois C, Pilote S, Arseneault M, Robitaille NM, Turgeon J, Hamelin BA. Effect of gender, sex hormones, time variables and physiological urinary pH on apparent CYP2D6 activity as assessed by metabolic ratios of marker substrates. PHARMACOGENETICS 2000; 10:425-38. [PMID: 10898112 DOI: 10.1097/00008571-200007000-00006] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The effects of gender, time variables, menstrual cycle phases, plasma sex hormone concentrations and physiologic urinary pH on CYP2D6 phenotyping were studied using two widely employed CYP2D6 probe drugs, namely dextromethorphan and metoprolol. Phenotyping on a single occasion of 150 young, healthy, drug-free women and men revealed that the dextromethorphan: dextrorphan metabolic ratio (MR) was significantly lower (P < 0.0001) in 56 female extensive metabolizers (0.008+/-0.021) compared to 86 male extensive metabolizers (0.020 +/-0.040). Urinary pH was a significant predictor of dextromethorphan: dextrorphan MRs in men and women (P < 0.001). Once-a-month phenotyping with dextromethorphan of 12 healthy young men (eight extensive metabolizers and four poor metabolizers) over a 1-year period, as well as every-other-day phenotyping with dextromethorphan of healthy, pre-menopausal women (10 extensive metabolizers and 2 poor metabolizers) during a complete menstrual cycle, did not follow a particular pattern and showed similar intrasubject variability ranging from 24.1% to 74.5% (mean 50.9%) in men and from 20.5% to 96.2% (mean 52.0%) in women, independent of the CYP2D6 phenotype (P = 0.342). Using metoprolol as a probe drug, considerable intrasubject variability (38.6+/- 12.0%) but no correlation between metoprolol: alpha-hydroxymetoprolol MRs and pre-ovulatory, ovulatory and luteal phases (mean +/- SD metoprolol: a-hydroxymetoprolol MRs: 1.086+/- 1.137 pre-ovulatory; 1.159+/-1.158 ovulatory and 1.002+/-1.405 luteal phase; P> 0.9) or 17beta-oestradiol, progesterone or testosterone plasma concentrations was observed. There was a significant inverse relationship between physiologic urinary pH and sequential dextromethorphan: dextrorphan MRs as well as metoprolol: alpha-hydroxymetoprolol MRs in men and women, with metabolic ratios varying up to six-fold with metoprolol and up to 20-fold with dextromethorphan (ANCOVA P < 0.001). We conclude that apparent CYP2D6 activity is highly variable, independent of menstrual cycle phases, sex hormones, time variables or phenotype. Up to 80% of the observed variability can be explained by variations of urinary pH within the physiological range. An apparent phenotype shift as a result of variations in urinary pH may be observed in individuals who have metabolic ratios close to the population antimode.
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Affiliation(s)
- L Labbé
- Faculty of Pharmacy, Laval University, Ste-Foy, Quebec, Canada
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Tucker GT. Advances in understanding drug metabolism and its contribution to variability in patient response. Ther Drug Monit 2000; 22:110-3. [PMID: 10688271 DOI: 10.1097/00007691-200002000-00023] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Recent advances in the understanding of the molecular biology and genetic variability of human drug metabolizing enzymes, particularly cytochromes P450, have contributed immensely towards clarifying the pharmacokinetics and pharmacodynamics of many existing drugs, and are increasingly important in the development of new chemical entities. However, whereas this knowledge has implications for therapeutics, appreciation and application in clinical practice have either been limited or yet to be realized. For example, the debrisoquine polymorphism was discovered 20 years ago, but controlled prospective studies to evaluate its clinical significance and pharmacoeconomic impact are few. Come the millennium it will be seen to what extent traditional therapeutic drug monitoring, involving the measurement of specific plasma drug concentrations, may be complemented or replaced by more general phenotyping or genotyping screens for human drug metabolizing enzymes.
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Affiliation(s)
- G T Tucker
- University of Sheffield, Section of Molecular Pharmacology & Pharmacogenetics, The Royal Hallamshire Hospital, UK
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