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Al-Qassabi J, Tan SPF, Phonboon P, Galetin A, Rostami-Hodjegan A, Scotcher D. Facing the Facts of Altered Plasma Protein Binding: Do Current Models Correctly Predict Changes in Fraction Unbound in Special Populations? J Pharm Sci 2024; 113:1664-1673. [PMID: 38417790 DOI: 10.1016/j.xphs.2024.02.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 02/22/2024] [Accepted: 02/22/2024] [Indexed: 03/01/2024]
Abstract
Accounting for variability in plasma protein binding of drugs is an essential input to physiologically-based pharmacokinetic (PBPK) models of special populations. Prediction of fraction unbound in plasma (fu) in such populations typically considers changes in plasma protein concentration while assuming that the binding affinity remains unchanged. A good correlation between predicted vs observed fu data reported for various drugs in a given special population is often used as a justification for such predictive methods. However, none of these analyses evaluated the prediction of the fold-change in fu in special populations relative to the reference population. This would be a more appropriate assessment of the predictivity, analogous to drug-drug interactions. In this study, predictive performance of the single protein binding model was assessed by predicting fu for alpha-1-acid glycoprotein and albumin bound drugs in hepatic impairment, renal impairment, paediatric, elderly, patients with inflammatory disease, and in different ethnic groups for a dataset of >200 drugs. For albumin models, the concordance correlation coefficients for predicted fu were >0.90 for 16 out of 17 populations with sub-groups, indicating strong agreement between predicted and observed values. In contrast, concordance correlation coefficients for predicted fold-change in fu for the same dataset were <0.38 for all populations and sub-groups. Trends were similar for alpha-1-acid glycoprotein models. Accordingly, the predictions of fu solely based on changes in protein concentrations in plasma cannot explain the observed values in some special populations. We recommend further consideration of the impact of changes in special populations to endogenous substances that competitively bind to plasma proteins, and changes in albumin structure due to posttranslational modifications. PBPK models of special populations for highly bound drugs should preferably use measured fu data to ensure reliable prediction of drug exposure or compare predicted unbound drug exposure between populations knowing that these will not be sensitive to changes in fu.
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Affiliation(s)
- Jokha Al-Qassabi
- Centre for Applied Pharmacokinetic Research, University of Manchester, Manchester, UK; University of Technology and Applied Sciences, Oman
| | - Shawn Pei Feng Tan
- Centre for Applied Pharmacokinetic Research, University of Manchester, Manchester, UK
| | - Patcharapan Phonboon
- Centre for Applied Pharmacokinetic Research, University of Manchester, Manchester, UK
| | - Aleksandra Galetin
- Centre for Applied Pharmacokinetic Research, University of Manchester, Manchester, UK
| | - Amin Rostami-Hodjegan
- Centre for Applied Pharmacokinetic Research, University of Manchester, Manchester, UK; Simcyp Division, Certara UK Limited, Sheffield, UK
| | - Daniel Scotcher
- Centre for Applied Pharmacokinetic Research, University of Manchester, Manchester, UK.
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Investigating the binding measurements of human α-acid glycoprotein with chlorambucil and dacarbazine in the presence of imidazolium based -ionic liquid by affinity capillary electrophoresis. ARAB J CHEM 2020. [DOI: 10.1016/j.arabjc.2020.08.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Temperature controlled ionic liquid aqueous two phase system combined with affinity capillary electrophoresis for rapid and precise pharmaceutical-protein binding measurements. Methods 2018; 146:120-125. [DOI: 10.1016/j.ymeth.2018.02.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 01/07/2018] [Accepted: 02/05/2018] [Indexed: 11/24/2022] Open
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Yasgar A, Furdas SD, Maloney DJ, Jadhav A, Jung M, Simeonov A. High-throughput 1,536-well fluorescence polarization assays for α(1)-acid glycoprotein and human serum albumin binding. PLoS One 2012; 7:e45594. [PMID: 23029124 PMCID: PMC3447978 DOI: 10.1371/journal.pone.0045594] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Accepted: 08/23/2012] [Indexed: 11/18/2022] Open
Abstract
Two major plasma proteins in humans are primarily responsible for drug binding, the α(1)-acid-glycoprotein (AGP) and human serum albumin (HSA). The availability of at least a semiquantitative high-throughput assay for assessment of protein binding is expected to aid in bridging the current gap between high-throughput screening and early lead discovery, where cell-based and biochemical assays are deployed routinely to test up to several million compounds rapidly, as opposed to the late-stage candidate drug profiling methods which test at most dozens of compounds at a time. Here, we describe the miniaturization of a pair of assays based on the binding- and displacement-induced changes in fluorescence polarization (FP) of fluorescent small molecule probes known to specifically target the drug-binding sites of these two proteins. A robust and reproducible assay performance was achieved in ≤4 µL assay volume in 1,536-well format. The assays were tested against a validation set of 10 known protein binders, and the results compared favorably with data obtained using protein-coated beads with high-performance liquid chromatography analysis. The miniaturized assays were taken to a high-throughput level in a screen of the LOPAC(1280) collection of 1,280 pharmacologically active compounds. The adaptation of the AGP and HSA FP assays to a 1,536-well format should allow their use in early-stage profiling of large-size compound sets.
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Affiliation(s)
- Adam Yasgar
- NIH Chemical Genomics Center, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Silviya D. Furdas
- Institute of Pharmaceutical Sciences, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - David J. Maloney
- NIH Chemical Genomics Center, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Ajit Jadhav
- NIH Chemical Genomics Center, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Manfred Jung
- Institute of Pharmaceutical Sciences, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Anton Simeonov
- NIH Chemical Genomics Center, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland, United States of America
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Carmona M, Pereira V, Malbouisson L, Auler Jr. J, Santos S. Effect of cardiopulmonary bypass on the pharmacokinetics of propranolol and atenolol. Braz J Med Biol Res 2009; 42:574-81. [DOI: 10.1590/s0100-879x2009000600016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2008] [Accepted: 02/26/2009] [Indexed: 11/21/2022] Open
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Carmona MJC, Malbouisson LMS, Pereira VA, Bertoline MA, Omosako CEK, Le Bihan KB, Auler JOC, Santos SRCJ. Cardiopulmonary bypass alters the pharmacokinetics of propranolol in patients undergoing cardiac surgery. Braz J Med Biol Res 2005; 38:713-21. [PMID: 15917952 DOI: 10.1590/s0100-879x2005000500008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The pharmacokinetics of propranolol may be altered by hypothermic cardiopulmonary bypass (CPB), resulting in unpredictable postoperative hemodynamic responses to usual doses. The objective of the present study was to investigate the pharmacokinetics of propranolol in patients undergoing coronary artery bypass grafting (CABG) by CPB under moderate hypothermia. We evaluated 11 patients, 4 women and 7 men (mean age 57 +/- 8 years, mean weight 75.4 +/- 11.9 kg and mean body surface area 1.83 +/- 0.19 m(2)), receiving propranolol before surgery (80-240 mg a day) and postoperatively (10 mg a day). Plasma propranolol levels were measured before and after CPB by high-performance liquid chromatography. Pharmacokinetic Solutions 2.0 software was used to estimate the pharmacokinetic parameters after administration of the drug pre- and postoperatively. There was an increase of biological half-life from 4.5 (95% CI = 3.9-6.9) to 10.6 h (95% CI = 8.2-14.7; P < 0.01) and an increase in volume of distribution from 4.9 (95% CI = 3.2-14.3) to 8.3 l/kg (95% CI = 6.5-32.1; P < 0.05), while total clearance remained unchanged 9.2 (95% CI = 7.7-24.6) vs 10.7 ml min(-1) kg(-1) (95% CI = 7.7-26.6; NS) after surgery. In conclusion, increases in drug distribution could be explained in part by hemodilution during CPB. On the other hand, the increase of biological half-life can be attributed to changes in hepatic metabolism induced by CPB under moderate hypothermia. These alterations in the pharmacokinetics of propranolol after CABG with hypothermic CPB might induce a greater myocardial depression in response to propranolol than would be expected with an equivalent dose during the postoperative period.
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Affiliation(s)
- M J C Carmona
- Disciplina de Anestesiologia, Serviço de Anestesiologia e Terapia Intensiva Cirúrgica, Instituto do Coração, Hospital das Clínicas, Faculdade de Medicina, Universidade de São PauloSão Paulo, SP, Brasil.
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Abstract
As with other forms of stress, surgery is a time of fluctuating haemodynamics, physiological shifts, intense metabolic changes, and protein catabolism and anabolism. At times, these changes can occur within hours. There is a reasonable body of literature concerning the adverse effects of surgery on gastric emptying, but not on the effects of surgery on the distribution, metabolism and excretion of drugs. Gastric emptying is diminished or absent following major procedures, which prevent the delivery of orally administered drugs to their major site of absorption, the small bowel. Changes in the paracellular absorption of drugs may occur postoperatively, although transcellular absorption appears to be unimpaired. Distribution is affected by changes in blood volume, alterations in circulation, increases in the extracellular fluid and changes in the circulating plasma protein levels, such as albumin and alpha 1-acid glycoprotein. Little is known about alterations in drug metabolism following surgery. However, it has been shown that systemic hypoxia alters the function of some of the cytochrome P450 (CYP) system and increased levels of cytokines have an effect on the metabolism of at least 1 drug. In addition, the renal elimination of drugs is affected in patients postoperatively, although the effects of biliary clearance in this period are difficult to determine. Despite the lack of research into pharmacokinetics during the postoperative period, and given the immense and often sudden changes observed in patients post-surgery, it is reasonable to recommend vigilance with respect to drug therapy during this period.
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Affiliation(s)
- J M Kennedy
- School of Pharmacy, Dunedin School of Medicine, University of Otago, New Zealand.
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The kinetics of propranolol elimination from blood plasma and its distribution in myocardium and liver of rats with experimental inflammation and on the background of phenobarbital and cimetidine. Pharm Chem J 1998. [DOI: 10.1007/bf02464189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Kishino S, Nomura A, Di ZS, Sugawara M, Iseki K, Kakinoki S, Kitabatake A, Miyazaki K. Alpha-1-acid glycoprotein concentration and the protein binding of disopyramide in healthy subjects. J Clin Pharmacol 1995; 35:510-4. [PMID: 7657852 DOI: 10.1002/j.1552-4604.1995.tb04096.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Age- and gender-related changes in serum alpha 1-acid glycoprotein (AAG) concentration and the serum protein binding of disopyramide were examined after intensive medical examination. Based on the clinical chemistry tests over 51 points, 245 subjects were diagnosed as healthy and 71 subjects (22.5%) revealed an abnormal value for at least one item. In the healthy subjects, serum AAG concentration in men was significantly higher than in women (men, 0.78 +/- 0.18 mg/mL, mean +/- SD; women, 0.67 +/- 0.16 mg/mL). In contrast, there were no significant differences in the AAG concentration between age groups for men and women and in the unbound fraction of disopyramide. Gender changes AAG concentration. Age, however, does not change AAG concentration and the protein binding of the basic drug.
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Affiliation(s)
- S Kishino
- Department of Pharmacy, School of Medicine, Hokkaido University, Sapporo, Japan
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Sager G, Jaeger R, Little C. Binding of prazosin to alpha 1-acid glycoprotein and albumin: effect of protein purity and concentrations. PHARMACOLOGY & TOXICOLOGY 1989; 64:365-8. [PMID: 2748545 DOI: 10.1111/j.1600-0773.1989.tb00666.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Prazosin is extensively bound in human serum/plasma. In the present study a bound fraction of 93-95% was observed at 37 degrees for therapeutic drug concentrations. Both alpha 1-acid glycoprotein (AAG) and albumin (HSA) are established as transport proteins for prazosin, but their individual contribution to the extent and variability of protein binding in serum/plasma is unclear. The present study showed that AAG possesses one binding site per molecule with high affinity (Kd approximately 0.8 microM) for prazosin. HSA, essentially globulin-free, bound prazosin with lower affinity (Kd approximately 30 microM) with an average of 0.3 binding sites per molecule. However, less purified HSA, containing globulins, exhibited apparently higher affinity (Kd approximately 8 microM), but lower binding capacity (0.07 sites per molecule) for prazosin. In mixtures of highly purified proteins, the concentrations of AAG, and not HSA, determined the extent and variability of prazosin binding.
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Affiliation(s)
- G Sager
- Department of Pharmacology, University of Tromsø, Norway
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