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Chang C, Vong C, Wang X, Hazra A, Diehl A, Nicholas T, Mukherjee A. Tofacitinib pharmacokinetics in children and adolescents with juvenile idiopathic arthritis. CPT Pharmacometrics Syst Pharmacol 2024; 13:599-611. [PMID: 38298058 PMCID: PMC11015083 DOI: 10.1002/psp4.13104] [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: 02/21/2023] [Revised: 12/14/2023] [Accepted: 12/31/2023] [Indexed: 02/02/2024] Open
Abstract
These analyses characterized tofacitinib pharmacokinetics (PKs) in children and adolescents with juvenile idiopathic arthritis (JIA). Data were pooled from phase I (NCT01513902), phase III (NCT02592434), and open-label, long-term extension (NCT01500551) studies of tofacitinib tablet/solution (weight-based doses administered twice daily [b.i.d.]) in patients with JIA aged 2 to less than 18 years. Population PK modeling used a nonlinear mixed-effects approach, with covariates identified using stepwise forward-inclusion backward-deletion procedures. Simulations were performed to derive dosing recommendations for children and adolescents with JIA. Two hundred forty-six pediatric patients were included in the population PK model. A one-compartment model with first-order elimination and absorption with body weight as a covariate for oral clearance and apparent volume of distribution sufficiently described the data. Oral solution was associated with comparable average concentration (Cavg) and slightly higher (113.9%) maximum concentration (Cmax) versus tablet, which was confirmed by a subsequent randomized, open-label, bioavailability study conducted in healthy adult participants (n = 12) by demonstrating adjusted geometric mean ratios (90% confidence interval) between oral solution and tablet of 1.04 (1.00-1.09) and 1.10 (1.00-1.21) for area under the curve extrapolated to infinity and Cmax, respectively (NCT04111614). A dosing regimen of 3.2 mg b.i.d. solution in patients 10 to less than 20 kg, 4 mg b.i.d. solution in patients 20 to less than 40 kg, and 5 mg b.i.d. tablet/solution in patients greater than or equal to 40 kg, irrespective of age, was proposed to achieve constant Cavg across weight groups. In summary, population PK characterization informed a simplified tofacitinib dosing regimen that has been implemented in pediatric patients with JIA.
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Light, Water, and Melatonin: The Synergistic Regulation of Phase Separation in Dementia. Int J Mol Sci 2023; 24:ijms24065835. [PMID: 36982909 PMCID: PMC10054283 DOI: 10.3390/ijms24065835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 03/17/2023] [Indexed: 03/22/2023] Open
Abstract
The swift rise in acceptance of molecular principles defining phase separation by a broad array of scientific disciplines is shadowed by increasing discoveries linking phase separation to pathological aggregations associated with numerous neurodegenerative disorders, including Alzheimer’s disease, that contribute to dementia. Phase separation is powered by multivalent macromolecular interactions. Importantly, the release of water molecules from protein hydration shells into bulk creates entropic gains that promote phase separation and the subsequent generation of insoluble cytotoxic aggregates that drive healthy brain cells into diseased states. Higher viscosity in interfacial waters and limited hydration in interiors of biomolecular condensates facilitate phase separation. Light, water, and melatonin constitute an ancient synergy that ensures adequate protein hydration to prevent aberrant phase separation. The 670 nm visible red wavelength found in sunlight and employed in photobiomodulation reduces interfacial and mitochondrial matrix viscosity to enhance ATP production via increasing ATP synthase motor efficiency. Melatonin is a potent antioxidant that lowers viscosity to increase ATP by scavenging excess reactive oxygen species and free radicals. Reduced viscosity by light and melatonin elevates the availability of free water molecules that allow melatonin to adopt favorable conformations that enhance intrinsic features, including binding interactions with adenosine that reinforces the adenosine moiety effect of ATP responsible for preventing water removal that causes hydrophobic collapse and aggregation in phase separation. Precise recalibration of interspecies melatonin dosages that account for differences in metabolic rates and bioavailability will ensure the efficacious reinstatement of the once-powerful ancient synergy between light, water, and melatonin in a modern world.
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Choi S, Han S, Lee SJ, Lim B, Bae SH, Han S, Yim DS. DallphinAtoM: Physiologically based pharmacokinetics software predicting human PK parameters based on physicochemical properties, in vitro and animal in vivo data. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 216:106662. [PMID: 35151112 DOI: 10.1016/j.cmpb.2022.106662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 11/12/2021] [Accepted: 01/24/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND AND OBJECTIVES In silico experiments and simulations using physiologically based pharmacokinetic (PBPK) and allometric approaches have played an important role in pharmaceutical research and drug development. These methods integrate diverse data from preclinical and clinical development, and have been widely applied to in vitro-in vivo extrapolation (IVIVE) of absorption, distribution, metabolism, and excretion (ADME). METHODS To develop a user-friendly open tool predicting human PK, we assessed various references on PBPK and allometric methods published so far. They were integrated into a software system named "DallphinAtoM" (Drugs with ALLometry and PHysiology Inside-Animal to huMan), which has a user-friendly platform that can handle complex PBPK models and allometric models with a relatively small amount of essential information of the drug. The models of DallphinAtoM support the integration of data gained during the nonclinical development phase, enable translation from animal to human, and allow the prediction of concentration-time profiles with predicted PK parameters. RESULTS We presented two illustrative applications using DallphinAtoM: (1) human PK simulation of an orally administered drug using PBPK method; and (2) simulation of intravenous infusion following a two-compartment model using the allometric scaling method. CONCLUSIONS We conclude that this is a straightforward and transparent tool allowing fast and reliable human PK simulation based on the latest knowledge on biochemical processes and physiology and provides valuable information for decision making during the early-phase drug development.
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Affiliation(s)
- Suein Choi
- Department of Clinical Pharmacology and Therapeutics, Seoul St. Mary's Hospital, 222 Banpo-daero, Seocho-gu, Seoul 06591, Republic of Korea; PIPET (Pharmacometrics Institute for Practical Education and Training), College of Medicine, The Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul 06591, Republic of Korea
| | - Sungpil Han
- Department of Clinical Pharmacology and Therapeutics, Seoul St. Mary's Hospital, 222 Banpo-daero, Seocho-gu, Seoul 06591, Republic of Korea; PIPET (Pharmacometrics Institute for Practical Education and Training), College of Medicine, The Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul 06591, Republic of Korea
| | - So Jin Lee
- PIPET (Pharmacometrics Institute for Practical Education and Training), College of Medicine, The Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul 06591, Republic of Korea; Q-fitter Inc., Seoul 06578, Republic of Korea
| | - Byunghee Lim
- PIPET (Pharmacometrics Institute for Practical Education and Training), College of Medicine, The Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul 06591, Republic of Korea
| | | | - Seunghoon Han
- Department of Clinical Pharmacology and Therapeutics, Seoul St. Mary's Hospital, 222 Banpo-daero, Seocho-gu, Seoul 06591, Republic of Korea; PIPET (Pharmacometrics Institute for Practical Education and Training), College of Medicine, The Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul 06591, Republic of Korea
| | - Dong-Seok Yim
- Department of Clinical Pharmacology and Therapeutics, Seoul St. Mary's Hospital, 222 Banpo-daero, Seocho-gu, Seoul 06591, Republic of Korea; PIPET (Pharmacometrics Institute for Practical Education and Training), College of Medicine, The Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul 06591, Republic of Korea.
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Muda MR, Harun SN, Syed Sulaiman SA, Sheikh Ghadzi SM. Population Pharmacokinetics Analyses of Rifampicin in Adult and Children Populations: A Systematic Review. Br J Clin Pharmacol 2022; 88:3132-3152. [PMID: 35253251 DOI: 10.1111/bcp.15298] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 02/05/2022] [Accepted: 02/09/2022] [Indexed: 11/27/2022] Open
Abstract
AIMS Rifampicin has become an essential component as the first-line therapy for pulmonary tuberculosis (PTB). Several population pharmacokinetic (PK) studies on rifampicin in the adult and children population have been studied previously. Therefore, the aims of the systematic review were (i) to summarize the relevant published studies and significant covariates that influence the PK of rifampicin across different populations, (ii) to identify any knowledge gap that requires additional research in the future. METHODS A total of 121 relevant population PK articles were systematically identified using PubMed and Scopus from inception to October 2021. Review articles, in-vitro, and physiological methods, animal studies, and noncompartmental analysis were excluded. RESULTS 19 studies which 16 involved adults, two involved children, and one involved both adults and children were included in the review. The structural model of rifampicin can be described as one compartment with a transient compartment absorption model and first-order elimination in most of the studies. Pharmaceutical formulation, body weight, gender, pregnancy status, diabetes, and nutritional supplementation were found to be the significant covariates that affect the PK parameters. External validation of the developed PK model was only conducted in two studies. CONCLUSIONS The source of variability for PK parameters of rifampicin remains inconsistent and poorly understood even though there were many potential covariates investigated in the selected studies. Exploring other possible factors and implementation a strict sampling strategy by considering the induction effects might unravel precise and reliable information. Furthermore, external validation should be frequently conducted to produce better predictability of model performance.
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Affiliation(s)
- Mohd Rahimi Muda
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, Penang, Malaysia.,Faculty of Pharmacy, Universiti Teknologi MARA Selangor, Bandar Puncak Alam, Selangor, Malaysia
| | - Sabariah Noor Harun
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, Penang, Malaysia
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Franzese RC, McFadyen L, Watson KJ, Riccobene T, Carrothers TJ, Vourvahis M, Chan PL, Raber S, Bradley JS, Lovern M. Population Pharmacokinetic Modeling and Probability of Pharmacodynamic Target Attainment for Ceftazidime-Avibactam in Pediatric Patients Aged 3 Months and Older. Clin Pharmacol Ther 2022; 111:635-645. [PMID: 34687548 PMCID: PMC9298731 DOI: 10.1002/cpt.2460] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 10/18/2021] [Indexed: 11/08/2022]
Abstract
Increasing prevalence of infections caused by antimicrobial-resistant gram-negative bacteria represents a global health crisis, and while several novel therapies that target various aspects of antimicrobial resistance have been introduced in recent years, few are currently approved for children. Ceftazidime-avibactam is a novel β-lactam β-lactamase inhibitor combination approved for adults and children 3 months and older with complicated intra-abdominal infection, and complicated urinary tract infection or hospital-acquired ventilator-associated pneumonia (adults only in the United States) caused by susceptible gram-negative bacteria. Extensive population pharmacokinetic (PK) data sets for ceftazidime and avibactam obtained during the adult clinical development program were used to iteratively select, modify, and validate the approved adult dosage regimen (2,000-500 mg by 2-hour intravenous (IV) infusion every 8 hours (q8h), with adjustments for renal function). Following the completion of one phase I (NCT01893346) and two phase II ceftazidime-avibactam studies (NCT02475733 and NCT02497781) in children, adult PK data sets were updated with pediatric PK data. This paper describes the development of updated combined adult and pediatric population PK models and their application in characterizing the population PK of ceftazidime and avibactam in children, and in dose selection for further pediatric evaluation. The updated models supported the approval of ceftazidime-avibactam pediatric dosage regimens (all by 2-hour IV infusion) of 50-12.5 mg/kg (maximum 2,000-500 mg) q8h for those ≥6 months to 18 years old, and 40-10 mg/kg q8h for those ≥3 to 6 months old with creatinine clearance > 50 mL/min/1.73 m2 .
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Affiliation(s)
| | | | | | | | | | | | | | | | - John S. Bradley
- Rady Children’s Hospital/University of California San Diego School of MedicineSan DiegoCaliforniaUSA
| | - Mark Lovern
- Certara Strategic ConsultingRaleighNorth CarolinaUSA
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González-Sales M, Holford N, Bonnefois G, Desrochers J. Wide size dispersion and use of body composition and maturation improves the reliability of allometric exponent estimates. J Pharmacokinet Pharmacodyn 2021; 49:151-165. [PMID: 34609707 DOI: 10.1007/s10928-021-09788-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 09/26/2021] [Indexed: 11/29/2022]
Abstract
To evaluate study designs and the influence of dispersion of body size, body composition and maturation of clearance or reliable estimation of allometric exponents. Non-linear mixed effects modeling and parametric bootstrap were employed to assess how the study sample size, number of observations per subject, between subject variability (BSV) and dispersion of size distribution affected estimation bias and uncertainty of allometric exponents. The role of covariate model misspecification was investigated using a large data set ranging from neonates to adults. A decrease in study sample size, number of observations per subject, an increase in BSV and a decrease in dispersion of size distribution, increased the uncertainty of allometric exponent estimates. Studies conducted only in adults with drugs exhibiting normal (30%) BSV in clearance may need to include at least 1000 subjects to be able to distinguish between allometric exponents of 2/3 and 1. Nevertheless, studies including both children and adults can distinguish these exponents with only 100 subjects. A marked bias of 45% (95%CI 41-49%) in the estimate of the allometric exponent of clearance was obtained when maturation and body composition were ignored in infants. A wide dispersion of body size (e.g. infants, children and adults) is required to reliably estimate allometric exponents. Ignoring differences in body composition and maturation of clearance may bias the exponent for clearance. Therefore, pharmacometricians should avoid estimating allometric exponent parameters without suitable designs and covariate models. Instead, they are encouraged to rely on the well-developed theory and evidence that clearance and volume parameters in humans scale with theory-based exponents.
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Affiliation(s)
| | - Nick Holford
- Department of Pharmacology and Clinical Pharmacology, University of Auckland, Auckland, New Zealand
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Uehara S, Yoneda N, Higuchi Y, Yamazaki H, Suemizu H. Oxidative metabolism and pharmacokinetics of the EGFR inhibitor BIBX1382 in chimeric NOG-TKm30 mice transplanted with human hepatocytes. Drug Metab Pharmacokinet 2021; 41:100419. [PMID: 34624627 DOI: 10.1016/j.dmpk.2021.100419] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 08/16/2021] [Accepted: 08/17/2021] [Indexed: 12/27/2022]
Abstract
The epidermal growth factor receptor inhibitor BIBX1382 has failed in drug development because of poor oral exposure and low bioavailability associated with its extensive metabolism by aldehyde oxidase (AOX) in humans. In this study, we investigated the metabolic profiles and pharmacokinetics of BIBX1382 in chimeric NOG-TKm30 mice with humanized liver (humanized liver mice). After intravenous and oral BIBX1382 administration, increased plasma clearance and decreased oral exposure together with high production of the predominant oxidative metabolite (M1, BIBU1476) and secondary oxidized metabolite (M2) were observed in humanized liver mice. Extensive oxidation rates of BIBX1382 were observed in hepatocytes from humanized liver mice and were suppressed by the typical human AOX1 inhibitors raloxifene and hydralazine. Liver cytosolic fractions from humans, humanized liver mice, cynomolgus monkeys, minipigs, and guinea pigs, but not fractions from dogs, rabbits, rats, and mice, displayed high BIBX1382 clearance and resulted in oxidative metabolite production. These results indicate that humanized liver mice have human-type AOX activity based on the transplanted human liver AOX1 function. Humanized liver mice can be considered an important animal model for understanding the metabolism and pharmacokinetics of AOX drug substrates.
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Affiliation(s)
- Shotaro Uehara
- Central Institute for Experimental Animals, Kawasaki, Japan.
| | - Nao Yoneda
- Central Institute for Experimental Animals, Kawasaki, Japan
| | | | - Hiroshi Yamazaki
- Laboratory of Drug Metabolism and Pharmacokinetics, Showa Pharmaceutical University, Machida, Japan
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Tatipalli M, Siripuram VK, Long T, Shuster D, Bernstein G, Martineau P, Cook KA, Cristofoletti R, Schmidt S, Vozmediano V. Model-Informed Optimization of a Pediatric Clinical Pharmacokinetic Trial of a New Spironolactone Liquid Formulation. Pharmaceutics 2021; 13:pharmaceutics13060849. [PMID: 34201093 PMCID: PMC8228864 DOI: 10.3390/pharmaceutics13060849] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 04/26/2021] [Accepted: 05/31/2021] [Indexed: 11/25/2022] Open
Abstract
Quantitative pharmacology brings important advantages in the design and conduct of pediatric clinical trials. Herein, we demonstrate the application of a model-based approach to select doses and pharmacokinetic sampling scenarios for the clinical evaluation of a novel oral suspension of spironolactone in pediatric patients with edema. A population pharmacokinetic model was developed and qualified for spironolactone and its metabolite, canrenone, using data from adults and bridged to pediatrics (2 to <17 years old) using allometric scaling. The model was then used via simulation to explore different dosing and sampling scenarios. Doses of 0.5 and 1.5 mg/kg led to target exposures (i.e., similar to 25 and 100 mg of the reference product in adults) in all the reference pediatric ages (i.e., 2, 6, 12 and 17 years). Additionally, two different sampling scenarios were delineated to accommodate patients into sparse sampling schemes informative to characterize drug pharmacokinetics while minimizing phlebotomy and burden to participating children.
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Affiliation(s)
- Manasa Tatipalli
- Center for Pharmacometrics and Systems Pharmacology, Department of Pharmaceutics, University of Florida, Gainesville, FL 32827, USA; (M.T.); (V.K.S.); (T.L.); (R.C.); (S.S.)
| | - Vijay Kumar Siripuram
- Center for Pharmacometrics and Systems Pharmacology, Department of Pharmaceutics, University of Florida, Gainesville, FL 32827, USA; (M.T.); (V.K.S.); (T.L.); (R.C.); (S.S.)
| | - Tao Long
- Center for Pharmacometrics and Systems Pharmacology, Department of Pharmaceutics, University of Florida, Gainesville, FL 32827, USA; (M.T.); (V.K.S.); (T.L.); (R.C.); (S.S.)
| | - Diana Shuster
- PRA Health Sciences, Raleigh, NC 27612, USA; (D.S.); (P.M.)
| | | | | | - Kim A. Cook
- Kiel Laboratories, Inc., Flowery Branch, GA 30542, USA;
| | - Rodrigo Cristofoletti
- Center for Pharmacometrics and Systems Pharmacology, Department of Pharmaceutics, University of Florida, Gainesville, FL 32827, USA; (M.T.); (V.K.S.); (T.L.); (R.C.); (S.S.)
| | - Stephan Schmidt
- Center for Pharmacometrics and Systems Pharmacology, Department of Pharmaceutics, University of Florida, Gainesville, FL 32827, USA; (M.T.); (V.K.S.); (T.L.); (R.C.); (S.S.)
| | - Valvanera Vozmediano
- Center for Pharmacometrics and Systems Pharmacology, Department of Pharmaceutics, University of Florida, Gainesville, FL 32827, USA; (M.T.); (V.K.S.); (T.L.); (R.C.); (S.S.)
- Correspondence: ; Tel.: +1-4073137052
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Human risk assessment of di-isobutyl phthalate through the application of a developed physiologically based pharmacokinetic model of di-isobutyl phthalate and its major metabolite mono-isobutyl phthalate. Arch Toxicol 2021; 95:2385-2402. [PMID: 33907876 DOI: 10.1007/s00204-021-03057-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Accepted: 04/21/2021] [Indexed: 10/21/2022]
Abstract
Di-isobutyl phthalate (DiBP) is a substance used in the production of objects frequently used in human life. Mono-isobutyl phthalate (MiBP), a major in vivo metabolite of DiBP, is a biomarker for DiBP exposure assessment. Therefore, risk assessment studies on DiBP and MiBP, which have not yet been reported in detail, are needed. The aim of this study was to develop and evaluate a physiologically based pharmacokinetic (PBPK) model for DiBP and MiBP in rats and extend this to human risk assessment based on human exposure. Pharmacokinetic studies were performed in male rats following the administration of 5-100 mg/kg DiBP, and these results were used for the development and validation of the PBPK model. In addition, the previous pharmacokinetic results in female rats following DiBP administration and the pharmacokinetic results in both males and females according to multiple exposures to DiBP were used to develop and validate the PBPK model. The metabolism of DiBP to MiBP in the body was very significant and rapid, and the biodistribution of MiBP was broad and major. Furthermore, the amount of MiBP in the body showed a correlation with DiBP exposure, and from this, a PBPK model was developed to evaluate the external exposure of DiBP from the internal exposure of MiBP. The predicted rat plasma, urine, fecal, and tissue concentrations using the developed PBPK model fitted well with the observed values. The established PBPK model for rats was extrapolated to a human PBPK model of DiBP and MiBP based on human physiological parameters and allometric scaling. The reference dose of 0.512 mg/kg/day of DiBP and external doses of 6.14-280.90 μg/kg/day DiBP for human risk assessment were estimated using Korean biomonitoring values. Valuable insight and approaches to assessing human health risks associated with DiBP exposure were provided by this study.
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Erhardt P, Bachmann K, Birkett D, Boberg M, Bodor N, Gibson G, Hawkins D, Hawksworth G, Hinson J, Koehler D, Kress B, Luniwal A, Masumoto H, Novak R, Portoghese P, Sarver J, Serafini MT, Trabbic C, Vermeulen N, Wrighton S. Glossary and tutorial of xenobiotic metabolism terms used during small molecule drug discovery and development (IUPAC Technical Report). PURE APPL CHEM 2021. [DOI: 10.1515/pac-2018-0208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Abstract
This project originated more than 15 years ago with the intent to produce a glossary of drug metabolism terms having definitions especially applicable for use by practicing medicinal chemists. A first-draft version underwent extensive beta-testing that, fortuitously, engaged international audiences in a wide range of disciplines involved in drug discovery and development. It became clear that the inclusion of information to enhance discussions among this mix of participants would be even more valuable. The present version retains a chemical structure theme while expanding tutorial comments that aim to bridge the various perspectives that may arise during interdisciplinary communications about a given term. This glossary is intended to be educational for early stage researchers, as well as useful for investigators at various levels who participate on today’s highly multidisciplinary, collaborative small molecule drug discovery teams.
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Affiliation(s)
- Paul Erhardt
- Center for Drug Design and Development , University of Toledo , Toledo , Ohio , USA
| | | | - Donald Birkett
- Department of Clinical Pharmacology , Flinders University , Adelaide , Australia (now Emeritus), (TGM)
| | - Michael Boberg
- Metabolism and Isotope Chemistry , Bayer , AG , Germany (now undetermined), (TGM)
| | - Nicholas Bodor
- Center for Drug Discovery , University of Florida , Belle Glade , FL , USA (now Emeritus Grad Res Prof/CEO Bodor Labs), (TGM)
| | - Gordon Gibson
- School of Biomedical and Life Sciences, University of Surrey , Surrey , UK (now deceased), (TGM)
| | - David Hawkins
- Huntingdon Life Sciences , Huntingdon , UK (now retired), (TGM)
| | - Gabrielle Hawksworth
- Department of Medicine and Therapeutics , University Aberdeen , Aberdeen , UK (now deceased), (TGM)
| | - Jack Hinson
- Division of Toxicology , University Arkansas for Medical Sciences , Little Rock , Arkansas , USA (now Emeritus Dist Prof), (TGM)
| | - Daniel Koehler
- Department of Pharmacology , University of Toledo , Toledo , Ohio , USA, (ST)
| | - Brian Kress
- Department of Medicinal and Biological Chemistry , University of Toledo , Toledo , Ohio , USA, (ST)
| | | | - Hiroshi Masumoto
- Drug Metabolism , Daiichi Pharm. Corp., Ltd. , Chuo , Tokyo , Japan (now retired), (TGM)
| | - Raymond Novak
- Institute of Environmental Health Science, Wayne State University , Detroit , Michigan , USA (now undetermined), (TGM)
| | - Phillip Portoghese
- Department of Medicinal Chemistry , University of Minnesota , Minneapolis , Minnesota , USA (now same), (TGM)
| | - Jeffrey Sarver
- Department of Pharmacology , University of Toledo , Toledo , Ohio , USA, (ST)
| | - M. Teresa Serafini
- Department of Pharmacokinetics and Drug Metabolism , Laboratories Dr. Esteve, S.A. , Barcelona , Spain (now Head Early ADME), (TGM)
| | | | - Nico Vermeulen
- Department of Pharmacochemistry , Vrije University , Amsterdam , Netherlands (now Emeritus Section Molecular Toxicology), (TGM)
| | - Steven Wrighton
- Eli Lilly, Inc. , Indianapolis , Indiana , USA (now retired), (TGM)
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Jeong SH, Jang JH, Cho HY, Lee YB. Risk assessment for humans using physiologically based pharmacokinetic model of diethyl phthalate and its major metabolite, monoethyl phthalate. Arch Toxicol 2020; 94:2377-2400. [PMID: 32303804 DOI: 10.1007/s00204-020-02748-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 04/08/2020] [Indexed: 11/24/2022]
Abstract
Diethyl phthalate (DEP) belongs to phthalates with short alkyl chains. It is a substance frequently used to make various products. Thus, humans are widely exposed to DEP from the surrounding environment such as food, soil, air, and water. As previously reported in many studies, DEP is an endocrine disruptor with reproductive toxicity. Monoethyl phthalate (MEP), a major metabolite of DEP in vivo, is a biomarker for DEP exposure assessment. It is also an endocrine disruptor with reproductive toxicity, similar to DEP. However, toxicokinetic studies on both MEP and DEP have not been reported in detail yet. Therefore, the objective of this study was to evaluate and develop physiologically based pharmacokinetic (PBPK) model for both DEP and MEP in rats and extend this to human risk assessment based on human exposure. This study was conducted in vivo after intravenous or oral administration of DEP into female (2 mg/kg dose) and male (0.1-10 mg/kg dose) rats. Biological samples consisted of urine, plasma, and 11 different tissues. These samples were analyzed using UPLC-ESI-MS/MS method. For DEP, the tissue to plasma partition coefficient was the highest in the kidney, followed by that in the liver. For MEP, the tissue to plasma partition coefficient was the highest in the liver. It was less than unity in all other tissues. Plasma, urine, and fecal samples were also obtained after IV administration of MEP (10 mg/kg dose) to male rats. All results were reflected in a model developed in this study, including in vivo conversion from DEP to MEP. Predicted concentrations of DEP and MEP in rat urine, plasma, and tissue samples using the developed PBPK model fitted well with observed values. We then extrapolated the PBPK model in rats to a human PBPK model of DEP and MEP based on human physiological parameters. Reference dose of 0.63 mg/kg/day (or 0.18 mg/kg/day) for DEP and external doses of 0.246 μg/kg/day (pregnant), 0.193 μg/kg/day (fetus), 1.005-1.253 μg/kg/day (adults), 0.356-0.376 μg/kg/day (adolescents), and 0.595-0.603 μg/kg/day (children) for DEP for human risk assessment were estimated using Korean biomonitoring values. Our study provides valuable insight into human health risk assessment regarding DEP exposure.
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Affiliation(s)
- Seung-Hyun Jeong
- College of Pharmacy, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju, 61186, Republic of Korea
| | - Ji-Hun Jang
- College of Pharmacy, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju, 61186, Republic of Korea
| | - Hea-Young Cho
- College of Pharmacy, CHA University, 335 Pangyo-ro, Bundang-gu, Seongnam-si, Gyeonggi-Do, 13488, Republic of Korea.
| | - Yong-Bok Lee
- College of Pharmacy, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju, 61186, Republic of Korea.
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Sinha J, Al-Sallami HS, Duffull SB. Choosing the Allometric Exponent in Covariate Model Building. Clin Pharmacokinet 2020; 58:89-100. [PMID: 29704107 DOI: 10.1007/s40262-018-0667-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
BACKGROUND Allometric scaling is often used to describe the covariate model linking total body weight (WT) to clearance (CL); however, there is no consensus on how to select its value. OBJECTIVES The aims of this study were to assess the influence of between-subject variability (BSV) and study design on (1) the power to correctly select the exponent from a priori choices, and (2) the power to obtain unbiased exponent estimates. METHODS The influence of WT distribution range (randomly sampled from the Third National Health and Nutrition Examination Survey, 1988-1994 [NHANES III] database), sample size (N = 10, 20, 50, 100, 200, 500, 1000 subjects), and BSV on CL (low 20%, normal 40%, high 60%) were assessed using stochastic simulation estimation. A priori exponent values used for the simulations were 0.67, 0.75, and 1, respectively. RESULTS For normal to high BSV drugs, it is almost impossible to correctly select the exponent from an a priori set of exponents, i.e. 1 vs. 0.75, 1 vs. 0.67, or 0.75 vs. 0.67 in regular studies involving < 200 adult participants. On the other hand, such regular study designs are sufficient to appropriately estimate the exponent. However, regular studies with < 100 patients risk potential bias in estimating the exponent. CONCLUSION Those study designs with limited sample size and narrow range of WT (e.g. < 100 adult participants) potentially risk either selection of a false value or yielding a biased estimate of the allometric exponent; however, such bias is only relevant in cases of extrapolating the value of CL outside the studied population, e.g. analysis of a study of adults that is used to extrapolate to children.
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Affiliation(s)
- Jaydeep Sinha
- School of Pharmacy, University of Otago, PO Box 56, Dunedin, 9054, New Zealand.
| | - Hesham S Al-Sallami
- School of Pharmacy, University of Otago, PO Box 56, Dunedin, 9054, New Zealand
| | - Stephen B Duffull
- School of Pharmacy, University of Otago, PO Box 56, Dunedin, 9054, New Zealand
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13
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Valic MS, Zheng G. Research tools for extrapolating the disposition and pharmacokinetics of nanomaterials from preclinical animals to humans. Theranostics 2019; 9:3365-3387. [PMID: 31244958 PMCID: PMC6567967 DOI: 10.7150/thno.34509] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 04/26/2019] [Indexed: 11/30/2022] Open
Abstract
A critical step in the translational science of nanomaterials from preclinical animal studies to humans is the comprehensive investigation of their disposition (or ADME) and pharmacokinetic behaviours. Disposition and pharmacokinetic data are ideally collected in different animal species (rodent and nonrodent), at different dose levels, and following multiple administrations. These data are used to assess the systemic exposure and effect to nanomaterials, primary determinants of their potential toxicity and therapeutic efficacy. At toxic doses in animal models, pharmacokinetic (termed toxicokinetic) data are related to toxicologic findings that inform the design of nonclinical toxicity studies and contribute to the determination of the maximum recommended starting dose in clinical phase 1 trials. Nanomaterials present a unique challenge for disposition and pharmacokinetic investigations owing to their prolonged circulation times, nonlinear pharmacokinetic profiles, and their extensive distribution into tissues. Predictive relationships between nanomaterial physicochemical properties and behaviours in vivo are lacking and are confounded by anatomical, physiological, and immunological differences amongst preclinical animal models and humans. These challenges are poorly understood and frequently overlooked by investigators, leading to inaccurate assumptions of disposition, pharmacokinetic, and toxicokinetics profiles across species that can have profoundly detrimental impacts for nonclinical toxicity studies and clinical phase 1 trials. Herein are highlighted two research tools for analysing and interpreting disposition and pharmacokinetic data from multiple species and for extrapolating this data accurately in humans. Empirical methodologies and mechanistic mathematical modelling approaches are discussed with emphasis placed on important considerations and caveats for representing nanomaterials, such as the importance of integrating physiological variables associated with the mononuclear phagocyte system (MPS) into extrapolation methods for nanomaterials. The application of these tools will be examined in recent examples of investigational and clinically approved nanomaterials. Finally, strategies for applying these extrapolation tools in a complementary manner to perform dose predictions and in silico toxicity assessments in humans will be explained. A greater familiarity with the available tools and prior experiences of extrapolating nanomaterial disposition and pharmacokinetics from preclinical animal models to humans will hopefully result in a more straightforward roadmap for the clinical translation of promising nanomaterials.
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Affiliation(s)
- Michael S. Valic
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, CANADA, M5G 1L7
| | - Gang Zheng
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, CANADA, M5G 1L7
- Department of Medical Biophysics, Institute of Biomaterials and Biomedical Engineering, and Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, CANADA, M5G 1L7
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14
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Vozmediano V, Lukas JC, Encinas E, Schmidt S, Sologuren A, Valiente R, Labeaga L, Campo C, Rodriguez M. Model-informed pediatric development applied to bilastine: Analysis of the clinical PK data and confirmation of the dose selected for the target population. Eur J Pharm Sci 2018; 128:180-192. [PMID: 30468868 DOI: 10.1016/j.ejps.2018.11.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 11/05/2018] [Accepted: 11/15/2018] [Indexed: 01/05/2023]
Abstract
Bilastine is a non-sedating second-generation H1 antihistamine approved for treatment of allergic rhinoconjunctivitis (AR) and urticaria (U) in adults at the oral (p.o.) dose of 20 mg once daily (OD). Optimal attributes can be anticipated for its clinical use in pediatrics due to its favorable safety and tolerability and age-independent PD profile. The aim of this work was to characterize bilastine PK in children through population modeling of data from a limited sampling confirmatory clinical trial in children with AR or U. The objective was also to ascertain whether the proposed dose (10 mg/day) in the target pediatric subset aged 2-<12 years matches the systemic exposure seen in adults at the 20 mg/day dose. A popPK model characterizing bilastine PK behavior in children aged from 4 to <12 years treated with 10 mg oral bilastine daily was successfully developed and qualified. No relationship was found between bilastine PK and age or weight; stopping rules pre-stablished to finalize the trial, i.e., model completeness and no dependence of exposure on decreasing age, were thus fulfilled. On a second step, the popPK model in children was linked to the PD model in adults assuming the same PD as described in adults and used to compare the PD outcome between both populations. Finally, an allometric scaling method and a physiological approximation were used to evaluate the suitability of the selected dose in the youngest children, showing that children from 2 years were deemed to belong to the same population as well. The achievement of comparable PK (i.e., within the range) to that observed in adults after the therapeutic dose of 20 mg, together with the achievement of similar PD and additional integrative analysis, served to confirm the validity of the 10 mg daily dose for the target pediatric subset (2 to <12 years).
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Affiliation(s)
- Valvanera Vozmediano
- Drug Modeling & Consulting, Dynakin, SL, Bilbao, Spain; Center for Pharmacometrics and Systems Pharmacology, Department of Pharmaceutics, University of Florida, United States of America.
| | - John C Lukas
- Drug Modeling & Consulting, Dynakin, SL, Bilbao, Spain
| | | | - Stephan Schmidt
- Center for Pharmacometrics and Systems Pharmacology, Department of Pharmaceutics, University of Florida, United States of America
| | - Ander Sologuren
- Clinical Research Department, FAES FARMA, SA, Leioa, Bizkaia, Spain
| | - Román Valiente
- Clinical Research Department, FAES FARMA, SA, Leioa, Bizkaia, Spain
| | - Luis Labeaga
- Clinical Research Department, FAES FARMA, SA, Leioa, Bizkaia, Spain
| | - Cristina Campo
- Clinical Research Department, FAES FARMA, SA, Leioa, Bizkaia, Spain
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15
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Schalkwijk S, Ter Heine R, Colbers AC, Huitema ADR, Denti P, Dooley KE, Capparelli E, Best BM, Cressey TR, Greupink R, Russel FGM, Mirochnick M, Burger DM. A Mechanism-Based Population Pharmacokinetic Analysis Assessing the Feasibility of Efavirenz Dose Reduction to 400 mg in Pregnant Women. Clin Pharmacokinet 2018; 57:1421-1433. [PMID: 29520730 PMCID: PMC6182466 DOI: 10.1007/s40262-018-0642-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND Reducing the dose of efavirenz can improve safety, reduce costs, and increase access for patients with HIV infection. According to the World Health Organization, a similar dosing strategy for all patient populations is desirable for universal roll-out; however, it remains unknown whether the 400 mg daily dose is adequate during pregnancy. METHODS We developed a mechanistic population pharmacokinetic model using pooled data from women included in seven studies (1968 samples, 774 collected during pregnancy). Total and free efavirenz exposure (AUC24 and C12) were predicted for 400 (reduced) and 600 mg (standard) doses in both pregnant and non-pregnant women. RESULTS Using a 400 mg dose, the median efavirenz total AUC24 and C12 during the third trimester of pregnancy were 91 and 87% of values among non-pregnant women, respectively. Furthermore, the median free efavirenz C12 and AUC24 were predicted to increase during pregnancy by 11 and 15%, respectively. CONCLUSIONS It was predicted that reduced-dose efavirenz provides adequate exposure during pregnancy. These findings warrant prospective confirmation.
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Affiliation(s)
- Stein Schalkwijk
- Department of Pharmacy, Radboud Institute for Health Sciences (RIHS), Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA, Nijmegen, The Netherlands.
- Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences (RIMLS), Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Rob Ter Heine
- Department of Pharmacy, Radboud Institute for Health Sciences (RIHS), Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA, Nijmegen, The Netherlands
| | - Angela C Colbers
- Department of Pharmacy, Radboud Institute for Health Sciences (RIHS), Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA, Nijmegen, The Netherlands
| | - Alwin D R Huitema
- Department of Pharmacy and Pharmacology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
- Department of Clinical Pharmacy, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Paolo Denti
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Kelly E Dooley
- Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Edmund Capparelli
- Skaggs School of Pharmacy and Pharmaceutical Sciences and School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Brookie M Best
- Skaggs School of Pharmacy and Pharmaceutical Sciences and School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Tim R Cressey
- Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai, Thailand
- Harvard T.H. Chan School of Public Health, Boston, MA, USA
- Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, UK
| | - Rick Greupink
- Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences (RIMLS), Radboud University Medical Center, Nijmegen, The Netherlands
| | - Frans G M Russel
- Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences (RIMLS), Radboud University Medical Center, Nijmegen, The Netherlands
| | | | - David M Burger
- Department of Pharmacy, Radboud Institute for Health Sciences (RIHS), Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA, Nijmegen, The Netherlands
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16
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Mandikian D, Figueroa I, Oldendorp A, Rafidi H, Ulufatu S, Schweiger MG, Couch JA, Dybdal N, Joseph SB, Prabhu S, Ferl GZ, Boswell CA. Tissue Physiology of Cynomolgus Monkeys: Cross-Species Comparison and Implications for Translational Pharmacology. AAPS JOURNAL 2018; 20:107. [PMID: 30298434 DOI: 10.1208/s12248-018-0264-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 09/10/2018] [Indexed: 01/08/2023]
Abstract
We previously performed a comparative assessment of tissue-level vascular physiological parameters in mice and rats, two of the most commonly utilized species in translational drug development. The present work extends this effort to non-human primates by measuring tissue- and organ-level vascular volumes (Vv), interstitial volumes (Vi), and blood flow rates (Q) in cynomolgus monkeys. These measurements were accomplished by red blood cell labeling, extracellular marker infusion, and rubidium chloride bolus distribution, respectively, the same methods used in previous rodent measurements. In addition, whole-body blood volumes (BV) were determined across species. The results demonstrate that Vv, Vi, and Q, measured using our methods scale approximately by body weight across mouse, rat, and monkey in the tissues considered here, where allometric analysis allowed extrapolation to human parameters. Significant differences were observed between the values determined in this study and those reported in the literature, including Vv in muscle, brain, and skin and Q in muscle, adipose, heart, thymus, and spleen. The impact of these differences for selected tissues was evaluated via sensitivity analysis using a physiologically based pharmacokinetic model. The blood-brain barrier in monkeys was shown to be more impervious to an infused radioactive tracer, indium-111-pentetate, than in mice or rats. The body weight-normalized total BV measured in monkey agreed well with previously measured value in rats but was lower than that in mice. These findings have important implications for the common practice of scaling physiological parameters from rodents to primates in translational pharmacology.
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Affiliation(s)
- Danielle Mandikian
- Preclinical and Translational Pharmacokinetics, Genentech Research and Early Development, South San Francisco, California, 94080, USA
| | - Isabel Figueroa
- Preclinical and Translational Pharmacokinetics, Genentech Research and Early Development, South San Francisco, California, 94080, USA
| | - Amy Oldendorp
- Safety Assessment, Genentech Research and Early Development, South San Francisco, California, 94080, USA
| | - Hanine Rafidi
- Preclinical and Translational Pharmacokinetics, Genentech Research and Early Development, South San Francisco, California, 94080, USA
| | - Sheila Ulufatu
- Safety Assessment, Genentech Research and Early Development, South San Francisco, California, 94080, USA
| | - Michelle G Schweiger
- Safety Assessment, Genentech Research and Early Development, South San Francisco, California, 94080, USA
| | - Jessica A Couch
- Safety Assessment, Genentech Research and Early Development, South San Francisco, California, 94080, USA
| | - Noel Dybdal
- Safety Assessment, Genentech Research and Early Development, South San Francisco, California, 94080, USA
| | - Sean B Joseph
- Preclinical and Translational Pharmacokinetics, Genentech Research and Early Development, South San Francisco, California, 94080, USA
| | - Saileta Prabhu
- Preclinical and Translational Pharmacokinetics, Genentech Research and Early Development, South San Francisco, California, 94080, USA
| | - Gregory Z Ferl
- Preclinical and Translational Pharmacokinetics, Genentech Research and Early Development, South San Francisco, California, 94080, USA. .,Genentech Inc., 1 DNA Way MS 463a, South San Francisco, California, 94080, USA.
| | - C Andrew Boswell
- Preclinical and Translational Pharmacokinetics, Genentech Research and Early Development, South San Francisco, California, 94080, USA. .,Genentech Inc., 1 DNA Way MS 463a, South San Francisco, California, 94080, USA.
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17
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Zang X, Kagan L. Physiologically-based modeling and interspecies prediction of paclitaxel pharmacokinetics. J Pharmacokinet Pharmacodyn 2018; 45:577-592. [PMID: 29671170 DOI: 10.1007/s10928-018-9586-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 04/05/2018] [Indexed: 12/20/2022]
Abstract
The objective was to develop a physiologically-based pharmacokinetic (PBPK) model to characterize the whole-body disposition of paclitaxel (formulated in Cremophor EL and ethanol-Taxol®) in mice and to evaluate the utility of this model for predicting pharmacokinetics in other species. Published studies that reported paclitaxel plasma and tissue concentration-time data following single intravenous bolus administration of Taxol® to mice were used; and the PBPK model included plasma, liver, lungs, kidneys, spleen, heart, gastrointestinal tract, and remainder compartments. The final model resulted in a good description of the experimental plasma and tissues data in mice, where all tissues were represented by a single compartment, except the remainder that included two sub-compartments. The predictive performance of the PBPK model was assessed by evaluating its utility in predicting pharmacokinetics of paclitaxel in rats and humans. The relationship between species body weights (mice, rats, rabbits, and humans) and plasma clearance was determined by power-based regression, and resulting allometric exponent was 0.86. The model demonstrated reasonable predictions of plasma and tissue paclitaxel concentration-time profiles in rats and plasma profiles in humans. The proposed PBPK model represents an important basis that can be further utilized for characterization of novel formulations of paclitaxel.
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Affiliation(s)
- Xiaowei Zang
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, 160 Frelinghuysen Road, Piscataway, NJ, 08854, USA
| | - Leonid Kagan
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, 160 Frelinghuysen Road, Piscataway, NJ, 08854, USA.
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18
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Kabadi SV, Fisher J, Aungst J, Rice P. Internal exposure-based pharmacokinetic evaluation of potential for biopersistence of 6:2 fluorotelomer alcohol (FTOH) and its metabolites. Food Chem Toxicol 2018; 112:375-382. [PMID: 29331735 DOI: 10.1016/j.fct.2018.01.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 01/05/2018] [Accepted: 01/08/2018] [Indexed: 11/26/2022]
Abstract
Polyfluorinated compounds (PFCs) are authorized for use as greaseproofing agents in food contact paper. As C8-PFCs (8-carbons) are known to accumulate in tissues, shorter-chain C6-PFCs (6-carbons) have replaced C8-PFCs in many food contact applications. However, the potential of C6-PFCs for human biopersistence has not been fully evaluated. For the first time, we provide internal exposure estimates to key metabolites of 6:2 fluorotelomer alcohol (6:2 FTOH), a monomeric component of C6-PFCs, to extend our understanding of exposure beyond estimates of external exposure. Pharmacokinetic data from published rat and human studies on 6:2 FTOH were used to estimate clearance and area under the curve (AUC) for its metabolites: 5:3 fluorotelomer carboxylic acid (5:3 A), perfluorohexanoic acid (PFHxA) and perfluoroheptanoic acid (PFHpA). Internal exposure to 5:3 A was the highest of evaluated metabolites across species and it had the slowest clearance. Additionally, 5:3 A clearance decreased with increasing 6:2 FTOH exposure. Our analysis provides insight into association of increased internal 5:3 A exposure with high biopersistence potential of 6:2 FTOH. Our results identify 5:3 A as an important biomarker of internal 6:2 FTOH exposure for use in biomonitoring studies, and are potentially useful for toxicological assessment of chronic dietary 6:2 FTOH exposure.
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Affiliation(s)
- Shruti V Kabadi
- FDA/CFSAN/OFAS/DFCN, 5001 Campus Drive, HFS 275, College Park, MD 20740, United States.
| | - Jeffrey Fisher
- FDA/NCTR, 3900 NCTR Road, Jefferson, AR 72079, United States
| | - Jason Aungst
- FDA/CFSAN/OFAS/DFCN, 5001 Campus Drive, HFS 275, College Park, MD 20740, United States
| | - Penelope Rice
- FDA/CFSAN/OFAS/DFCN, 5001 Campus Drive, HFS 275, College Park, MD 20740, United States
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Kim SJ, Shin H, Lee YB, Cho HY. Sex-specific risk assessment of PFHxS using a physiologically based pharmacokinetic model. Arch Toxicol 2017; 92:1113-1131. [PMID: 29143853 DOI: 10.1007/s00204-017-2116-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 11/08/2017] [Indexed: 12/19/2022]
Abstract
Perfluorohexanesulfonate (PFHxS), which belongs to the group of perfluoroalkyl and polyfluoroalkyl substances (PFASs), has been extensively used in industry and subsequently detected in the environment. Its use may be problematic, as PFHxS is known to induce neuronal cell death, and has been associated with early onset menopause in women and with attention deficit/hyperactivity disorder. Due to these impending issues, the aim of this study is to develop and evaluate a physiologically based pharmacokinetic (PBPK) model for PFHxS in male and female rats, and apply this to a human health risk assessment. We conducted this study in vivo after the oral or intravenous administration of PFHxS in male (dose of 10 mg/kg) and female rats (dose of 0.5-10 mg/kg). The biological samples consisted of plasma, nine tissues, urine, and feces. We analyzed the sample using ultra-liquid chromatography coupled tandem mass spectrometry (UPLC-MS/MS). Our findings showed the tissue-plasma partition coefficients for PFHxS were highest in the liver. The predicted rat plasma and tissue concentrations using a simulation fitted well with the observed values. We extrapolated the PBPK model in male and female rats to a human PBPK model of PFHxS based on human physiological parameters. The reference doses of 0.711 µg/kg/day (male) and 0.159 µg/kg/day (female) and external doses of 0.007 µg/kg/day (male) and 0.006 µg/kg/day (female) for human risk assessment were estimated using Korean biomonitoring values. This study provides valuable insight into human health risk assessment regarding PFHxS exposure.
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Affiliation(s)
- Sook-Jin Kim
- College of Pharmacy, CHA University, 335 Pangyo-ro, Bundang-gu, Seongnam-si, Gyeonggi-do, 13488, Republic of Korea
| | - Hwajin Shin
- College of Pharmacy, CHA University, 335 Pangyo-ro, Bundang-gu, Seongnam-si, Gyeonggi-do, 13488, Republic of Korea
| | - Yong-Bok Lee
- College of Pharmacy, Chonnam National University, 77 Yongbong-ro, Buk-Gu, Gwangju, 61186, Republic of Korea
| | - Hea-Young Cho
- College of Pharmacy, CHA University, 335 Pangyo-ro, Bundang-gu, Seongnam-si, Gyeonggi-do, 13488, Republic of Korea.
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Hubbard TD, Murray IA, Nichols RG, Cassel K, Podolsky M, Kuzu G, Tian Y, Smith P, Kennett MJ, Patterson AD, Perdew GH. Dietary Broccoli Impacts Microbial Community Structure and Attenuates Chemically Induced Colitis in Mice in an Ah receptor dependent manner. J Funct Foods 2017; 37:685-698. [PMID: 29242716 PMCID: PMC5726276 DOI: 10.1016/j.jff.2017.08.038] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Consumption of broccoli mediates numerous chemo-protective benefits through the intake of phytochemicals, some of which modulate aryl hydrocarbon receptor (AHR) activity. Whether AHR activation is a critical aspect of the therapeutic potential of dietary broccoli is not known. Here we administered isocaloric diets, with or without supplementation of whole broccoli (15% w/w), to congenic mice expressing the high-affinity Ahrb/b or low-affinity Ahrd/d alleles, for 24 days and examined the effects on AHR activity, intestinal microbial community structure, inflammatory status, and response to chemically induced colitis. Cecal microbial community structure and metabolic potential were segregated according to host dietary and AHR status. Dietary broccoli associated with heightened intestinal AHR activity, decreased microbial abundance of the family Erysipelotrichaceae, and attenuation of colitis. In summary, broccoli consumption elicited an enhanced response in ligand-sensitive Ahrb/b mice, demonstrating that in part the beneficial aspects of dietary broccoli upon intestinal health are associated with heightened AHR activity.
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Affiliation(s)
- Troy D. Hubbard
- Department of Veterinary and Biomedical Sciences and The Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, PA 16802
| | - Iain A. Murray
- Department of Veterinary and Biomedical Sciences and The Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, PA 16802
| | - Robert G. Nichols
- Department of Veterinary and Biomedical Sciences and The Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, PA 16802
| | - Kaitlyn Cassel
- Department of Veterinary and Biomedical Sciences and The Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, PA 16802
| | - Michael Podolsky
- Department of Veterinary and Biomedical Sciences and The Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, PA 16802
| | - Guray Kuzu
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802
| | - Yuan Tian
- Department of Veterinary and Biomedical Sciences and The Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, PA 16802
| | - Phillip Smith
- The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA 16802
| | - Mary J. Kennett
- Department of Veterinary and Biomedical Sciences and The Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, PA 16802
| | - Andrew D. Patterson
- Department of Veterinary and Biomedical Sciences and The Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, PA 16802
| | - Gary H. Perdew
- Department of Veterinary and Biomedical Sciences and The Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, PA 16802
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Lu XF, Zhan J, Zhou Y, Bi KS, Chen XH. Use of a semi-physiological pharmacokinetic model to investigate the influence of itraconazole on tacrolimus absorption, distribution and metabolism in mice. Xenobiotica 2016; 47:752-762. [PMID: 27533047 DOI: 10.1080/00498254.2016.1226003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
1. The aim of this study was to investigate the influence of itraconazole (ITCZ) on tacrolimus absorption, distribution and metabolism by developing a semi-physiological pharmacokinetic model of tacrolimus in mice. 2. Mice were randomly divided into four groups, namely control group (CG, taking 3 mg kg-1 tacrolimus only), low-dose group (LDG, taking tacrolimus with 12.5 mg kg-1 ITCZ), medium-dose group (MDG, taking tacrolimus with 25 mg kg-1 ITCZ) and high-dose group (HDG, taking tacrolimus with 50 mg kg-1 ITCZ). 3. Liver clearance (CLli) decreased significantly (**p < 0.01) in LDG (35.3%), MDG (45.2%) and HDG (58.7%) mice compared to CG mice. With respect to gut clearance (CLgu), significant (**p < 0.01) decrease was also revealed in LDG (35.9%), MDG (50.2%) and HDG (64.6%) mice. A significant (**p < 0.01) higher tacrolimus brain-to-blood partition coefficient (Kt,br) was found in MDG (25.3%) and HDG (55.9%) mice than in CG mice. Moreover, a significant (*p < 0.05) increase (16.3%) was found in the absorption rate constant (Ka) in HDG mice compared to CG mice. There was a significant (**p < 0.01) association between ITCZ dose and the change in CLgu (ΔCLgu, r= -0.790), the change in CLli (ΔCLli, r= -0.787) and the change in Kt,br (ΔKt,br, r = 0.727), while the association between ITCZ dose and the change in Ka (ΔKa) was not significant (p > 0.05). 4. These findings could be useful in predicting the efficacy and toxicity of tacrolimus, and drug-drug interaction of ITCZ and tarcolimus in human.
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Affiliation(s)
- Xue-Feng Lu
- a Department of Pharmaceutical Analysis , School of Pharmacy, Shenyang Pharmaceutical University , Shenyang , China
| | - Jian Zhan
- b Department of Pharmaceutics , School of Pharmacy, Shenyang Pharmaceutical University , Shenyang , China , and
| | - Yang Zhou
- c Department of Measurement and Control , School of Physics, Liaoning University , Shenyang , China
| | - Kai-Shun Bi
- a Department of Pharmaceutical Analysis , School of Pharmacy, Shenyang Pharmaceutical University , Shenyang , China
| | - Xiao-Hui Chen
- a Department of Pharmaceutical Analysis , School of Pharmacy, Shenyang Pharmaceutical University , Shenyang , China
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Lu XF, Bi K, Chen X. Physiologically based pharmacokinetic model of docetaxel and interspecies scaling: comparison of simple injection with folate receptor-targeting amphiphilic copolymer-modified liposomes. Xenobiotica 2016; 46:1093-1104. [DOI: 10.3109/00498254.2016.1155128] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Xue-Feng Lu
- Department of Pharmaceutical Analysis, School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, China
| | - Kaishun Bi
- Department of Pharmaceutical Analysis, School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, China
| | - Xiaohui Chen
- Department of Pharmaceutical Analysis, School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, China
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Sundqvist M, Lundahl A, Någård MB, Bredberg U, Gennemark P. Quantifying and Communicating Uncertainty in Preclinical Human Dose-Prediction. CPT-PHARMACOMETRICS & SYSTEMS PHARMACOLOGY 2015. [PMID: 26225248 PMCID: PMC4429578 DOI: 10.1002/psp4.32] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Human dose-prediction is fundamental for ranking lead-optimization compounds in drug discovery and to inform design of early clinical trials. This tutorial describes how uncertainty in such predictions can be quantified and efficiently communicated to facilitate decision-making. Using three drug-discovery case studies, we show how several uncertain pieces of input information can be integrated into one single uncomplicated plot with key predictions, including their uncertainties, for many compounds or for many scenarios, or both.
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Affiliation(s)
- M Sundqvist
- CVMD iMed DMPK, AstraZeneca R&D SE-431, 83, Mölndal, Sweden
| | - A Lundahl
- CVMD iMed DMPK, AstraZeneca R&D SE-431, 83, Mölndal, Sweden
| | - M B Någård
- CVMD iMed DMPK, AstraZeneca R&D SE-431, 83, Mölndal, Sweden
| | - U Bredberg
- CVMD iMed DMPK, AstraZeneca R&D SE-431, 83, Mölndal, Sweden
| | - P Gennemark
- CVMD iMed DMPK, AstraZeneca R&D SE-431, 83, Mölndal, Sweden
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Huang Q, Gehring R, Tell LA, Li M, Riviere JE. Interspecies allometric meta-analysis of the comparative pharmacokinetics of 85 drugs across veterinary and laboratory animal species. J Vet Pharmacol Ther 2014; 38:214-26. [DOI: 10.1111/jvp.12174] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Accepted: 09/15/2014] [Indexed: 11/28/2022]
Affiliation(s)
- Q. Huang
- Institute of Computational Comparative Medicine; Kansas State University; Manhattan KS USA
| | - R. Gehring
- Institute of Computational Comparative Medicine; Kansas State University; Manhattan KS USA
| | - L. A. Tell
- Department of Medicine and Epidemiology; School of Veterinary Medicine; University of California-Davis; Davis CA USA
| | - M. Li
- Institute of Computational Comparative Medicine; Kansas State University; Manhattan KS USA
| | - J. E. Riviere
- Institute of Computational Comparative Medicine; Kansas State University; Manhattan KS USA
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Sy SKB, Asin-Prieto E, Derendorf H, Samara E. Predicting pediatric age-matched weight and body mass index. AAPS JOURNAL 2014; 16:1372-9. [PMID: 25155824 DOI: 10.1208/s12248-014-9657-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Accepted: 08/05/2014] [Indexed: 01/30/2023]
Abstract
The empirical scaling from adult to pediatric using allometric size adjustments based on body weight continued to be the mainstream method for pediatric dose selection. Due to the flexibility of a polynomial function to conform to the data trend, an empirical function for simulating age-matched weight and body mass index by gender in the pediatric population is developed by using a polynomial function and a constant coefficient to describe the interindividual variability in weight. A polynomial of up to fifth order sufficiently described the pediatric data from the Center for Disease Control (CDC) and the World Health Organization (WHO). The coefficients of variation to describe the variability were within 17%. The percentages of the CDC simulated weights for pediatrics between 0 and 5 years that fell outside the WHO 90% and 95% confidence boundaries were well within the expected percentage values, indicating that the CDC dataset can be used to substitute for the WHO dataset for the purpose of pediatric drug development. To illustrate the utility of this empirical function, the CDC-based age-matched weights were simulated and were used in the prediction of the concentration-time profiles of tenofovir in children based on a population pharmacokinetic model whose parameters were allometrically scaled. We have shown that the resulting 95% prediction interval of tenofovir in newborn to 5 years of age was almost identical whether the weights were simulated based on WHO or CDC dataset. The approach is simple and is broadly applicable in adjusting for pediatric dosages using allometry.
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Affiliation(s)
- Sherwin K B Sy
- Department of Pharmaceutics, College of Pharmacy, University of Florida, 1345 Center Drive, PO Box 100494, Gainesville, Florida, 32610, USA
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Interspecies allometric scaling of antimalarial drugs and potential application to pediatric dosing. Antimicrob Agents Chemother 2014; 58:6068-78. [PMID: 25092696 DOI: 10.1128/aac.02538-14] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pharmacopeial recommendations for administration of antimalarial drugs are the same weight-based (mg/kg of body weight) doses for children and adults. However, linear calculations are known to underestimate pediatric doses; therefore, interspecies allometric scaling data may have a role in predicting doses in children. We investigated the allometric scaling relationships of antimalarial drugs using data from pharmacokinetic studies in mammalian species. Simple allometry (Y = a × W(b)) was utilized and compared to maximum life span potential (MLP) correction. All drugs showed a strong correlation with clearance (CL) in healthy controls. Insufficient data from malaria-infected species other than humans were available for allometric scaling. The allometric exponents (b) for CL of artesunate, dihydroartemisinin (from intravenous artesunate), artemether, artemisinin, clindamycin, piperaquine, mefloquine, and quinine were 0.71, 0.85, 0.66, 0.83, 0.62, 0.96, 0.52, and 0.40, respectively. Clearance was significantly lower in malaria infection than in healthy (adult) humans for quinine (0.07 versus 0.17 liter/h/kg; P = 0.0002) and dihydroartemisinin (0.81 versus 1.11 liters/h/kg; P = 0.04; power = 0.6). Interpolation of simple allometry provided better estimates of CL for children than MLP correction, which generally underestimated CL values. Pediatric dose calculations based on simple allometric exponents were 10 to 70% higher than pharmacopeial (mg/kg) recommendations. Interpolation of interspecies allometric scaling could provide better estimates than linear scaling of adult to pediatric doses of antimalarial drugs; however, the use of a fixed exponent for CL was not supported in the present study. The variability in allometric exponents for antimalarial drugs also has implications for scaling of fixed-dose combinations.
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Hu ZY, Lu J, Zhao Y. A physiologically based pharmacokinetic model of alvespimycin in mice and extrapolation to rats and humans. Br J Pharmacol 2014; 171:2778-89. [PMID: 24471734 PMCID: PMC4243854 DOI: 10.1111/bph.12609] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 11/10/2013] [Accepted: 01/09/2014] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND AND PURPOSE Alvespimycin, a new generation of heat shock protein 90 (Hsp90) inhibitor in clinical trial, is a promising therapeutic agent for cancer. Pharmacokinetic models of alvespimycin would help in the understanding of drug disposition, predicting drug exposure and interpreting dose-response relationship. In the present study we aimed to develop a physiologically based pharmacokinetic (PBPK) model of alvespimycin in mice and evaluate the utility of the model for predicting alvespimycin disposition in other species. EXPERIMENTAL APPROACH A literature search was performed to collect pharmacokinetic data for alvespimycin. A PBPK model was initially constructed to demonstrate the disposition of alvespimycin in mice, and then extrapolated to rats and humans by taking into account the interspecies differences in physiological- and chemical-specific parameters. KEY RESULTS A PBPK model, employing a permeability-limited model structure and saturable tissue binding, was built in mice. It successfully characterized the time course of the disposition of alvespimycin in mice. After extrapolation to rats, the model simulated the alvespimycin concentration-time profiles in rat tissues with acceptable accuracies. Likewise, a reasonable match was found between the observed and simulated human plasma pharmacokinetics of alvespimycin. CONCLUSIONS AND IMPLICATIONS The PBPK model described here is beneficial to the understanding and prediction of the effects of alvespimycin in different species. It also provides a good basis for further development, which necessitates additional studies, especially those needed to clarify the in-depth mechanism of alvespimycin elimination. A refined PBPK model would benefit the understanding of dose-response relationships and optimization of dosing regimens.
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Affiliation(s)
- Zhe-Yi Hu
- Department of Clinical Pharmacy, College of Pharmacy, University of Tennessee Health Science CenterMemphis, TN, USA
| | - Jingtao Lu
- The Hamner Institutes for Health SciencesResearch Triangle Park, NC, USA
| | - Yuansheng Zhao
- The Hamner Institutes for Health SciencesResearch Triangle Park, NC, USA
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Himebauch AS, Zuppa A. Methods for pharmacokinetic analysis in young children. Expert Opin Drug Metab Toxicol 2014; 10:497-509. [DOI: 10.1517/17425255.2014.885502] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Goss KU, Brown TN, Endo S. Elimination half-life as a metric for the bioaccumulation potential of chemicals in aquatic and terrestrial food chains. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2013; 32:1663-1671. [PMID: 23554060 DOI: 10.1002/etc.2229] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Revised: 02/19/2013] [Accepted: 03/25/2013] [Indexed: 06/02/2023]
Abstract
The assessment of chemicals as bioaccumulative in the regulatory process makes use of the bioconcentration factor as a metric. However, this metric does not account for the dietary uptake route and therefore cannot be applied to terrestrial food chains. In recent years, the biomagnification factor (BMF) and the trophic magnification factor (TMF) have been suggested as standard metrics for bioaccumulation. For regulatory purposes, though, the BMF and the TMF also suffer from a number of shortcomings. They are not applicable to assess uptake routes other than the diet (e.g., dermal uptake, as is important for personal care products). When measured in the field, they depend largely on biological and ecological factors and less so on the chemical's properties, and they are difficult to normalize and standardize. In the present study, the authors suggest the elimination half-life (EL0.5 ) of a chemical as an alternative metric for bioaccumulation. The EL0.5 is equivalent to the depuration rate constant (k2 ) that is measured in various bioaccumulation and bioconcentration tests. This metric can be applied to air- and water-breathing animals, and it is valuable for all uptake routes. It has a number of practical advantages over the BMF and the TMF. In combination with a standard uptake scenario, the EL0.5 can also be linked directly to a BMF threshold of unity. Thus, the EL0.5 as a bioaccumulation metric overcomes the shortcomings of the BMF and the TMF while still conserving the advantages of the latter metrics.
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Affiliation(s)
- Kai-Uwe Goss
- Department of Analytical Environmental Chemistry, UFZ-Helmholtz Centre for Environmental Research, Leipzig, Germany.
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31
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Amantana A, Chen Y, Tyavanagimatt SR, Jones KF, Jordan R, Chinsangaram J, Bolken TC, Leeds JM, Hruby DE. Pharmacokinetics and interspecies allometric scaling of ST-246, an oral antiviral therapeutic for treatment of orthopoxvirus infection. PLoS One 2013; 8:e61514. [PMID: 23637845 PMCID: PMC3630197 DOI: 10.1371/journal.pone.0061514] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 03/08/2013] [Indexed: 11/18/2022] Open
Abstract
Plasma pharmacokinetics of ST-246, smallpox therapeutic, was evaluated in mice, rabbits, monkeys and dogs following repeat oral administrations by gavage. The dog showed the lowest Tmax of 0.83 h and the monkey, the highest value of 3.25 h. A 2- to 4-fold greater dose-normalized Cmax was observed for the dog compared to the other species. The mouse showed the highest dose-normalized AUC, which was 2-fold greater than that for the rabbit and monkey both of which by approximation, recorded the lowest value. The Cl/F increased across species from 0.05 L/h for mouse to 42.52 L/h for dog. The mouse showed the lowest VD/F of 0.41 L and the monkey, the highest VD/F of 392.95 L. The calculated extraction ratios were 0.104, 0.363, 0.231 and 0.591 for mouse, rabbit, monkey and dog, respectively. The dog showed the lowest terminal half-life of 3.10 h and the monkey, the highest value of 9.94 h. The simple allometric human VD/F and MLP-corrected Cl/F were 2311.51 L and 51.35 L/h, respectively, with calculated human extraction ratio of 0.153 and terminal half-life of 31.20 h. Overall, a species-specific difference was observed for Cl/F with this parameter increasing across species from mouse to dog. The human MLP-corrected Cl/F, terminal half-life, extraction ratios were in close proximity to the observed estimates. In addition, the first-in-humans (FIH) dose of 485 mg, determined from the MLP-corrected allometry Cl/F, was well within the dose range of 400 mg and 600 mg administered in healthy adult human volunteers.
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Zhao W, Fakhoury M, Deschênes G, Roussey G, Brochard K, Niaudet P, Tsimaratos M, André JL, Cloarec S, Cochat P, Bensman A, Azougagh S, Jacqz-Aigrain E. Population Pharmacokinetics and Pharmacogenetics of Mycophenolic Acid Following Administration of Mycophenolate Mofetil in De Novo Pediatric Renal-Transplant Patients. J Clin Pharmacol 2013; 50:1280-91. [DOI: 10.1177/0091270009357429] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Milán Segovia RC, Domínguez Ramírez AM, Jung Cook H, Magaña Aquino M, Vigna Pérez M, Brundage RC, Romano Moreno S. Population pharmacokinetics of rifampicin in Mexican patients with tuberculosis. J Clin Pharm Ther 2012; 38:56-61. [PMID: 23167603 DOI: 10.1111/jcpt.12016] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
WHAT IS KNOWN AND OBJECTIVE Rifampicin (RIF) shows wide variability in its pharmacokinetics. The purpose of this study was to develop and validate a population pharmacokinetic model to characterize the inter- and intra-individual variability in pharmacokinetic parameters of RIF in Mexican patients. METHODS Ninety-four patients receiving antituberculosis therapy participated in this prospective study. Plasma concentration-time data were described using a one-compartment model with lag time, absorption and first-order elimination. The potential influence of demographic and clinical characteristics of the patients, and the pharmaceutical formulation (A, B, C and D) on the pharmacokinetics parameters, was evaluated by non-linear mixed-effect modelling (nonmem). Seventy-seven additional patients participated in the validation of the model. RESULTS AND DISCUSSION The final population pharmacokinetic model obtained was as follows: apparent clearance CL/F = 8·17 L/h (1·40 as high for males), apparent distribution volume V(d)/F = 50·1 L (1·29 as high for males), absorption rate constant K(aA) = 0·391/h, K(aB,C,D) = 2·70/h, relative bioavailability F(A) = 0·468, F(B,C,D) = 1, lag time in the absorption phase T(lag) = 0·264 h. The final model improved the precision on the parameter estimates (CL/F, V(d) /F and K(a) by 31·9%, 16·7% and 92·9%, respectively). The residual variability was 27·3%. WHAT IS NEW AND CONCLUSION Gender was associated with changes in CL/F and V(d) /F whereas the pharmaceutical formulation was associated with changes in F and altered the K(a) . The validation data set showed that the model could be used in clinical practice for Bayesian dose adjustment of RIF in TB patients.
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Affiliation(s)
- R C Milán Segovia
- Doctorado en Ciencias Biológicas y de la Salud, Universidad Autónoma Metropolitana, México.
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Pai MP. Drug Dosing Based on Weight and Body Surface Area: Mathematical Assumptions and Limitations in Obese Adults. Pharmacotherapy 2012; 32:856-68. [DOI: 10.1002/j.1875-9114.2012.01108.x] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Manjunath P. Pai
- Department of Pharmacy Practice; Albany College of Pharmacy and Health Sciences; Albany; New York
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Huh Y, Smith DE, Feng MR. Interspecies scaling and prediction of human clearance: comparison of small- and macro-molecule drugs. Xenobiotica 2011; 41:972-87. [PMID: 21892879 DOI: 10.3109/00498254.2011.598582] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Human clearance prediction for small- and macro-molecule drugs was evaluated and compared using various scaling methods and statistical analysis. Human clearance is generally well predicted using single or multiple species simple allometry for macro- and small-molecule drugs excreted renally. The prediction error is higher for hepatically eliminated small-molecules using single or multiple species simple allometry scaling, and it appears that the prediction error is mainly associated with drugs with low hepatic extraction ratio (Eh). The error in human clearance prediction for hepatically eliminated small-molecules was reduced using scaling methods with a correction of maximum life span (MLP) or brain weight (BRW). Human clearance of both small- and macro-molecule drugs is well predicted using the monkey liver blood flow method. Predictions using liver blood flow from other species did not work as well, especially for the small-molecule drugs.
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Affiliation(s)
- Yeamin Huh
- Department of Pharmaceutical Sciences, University of Michigan, Ann Arbor, Michigan, USA
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Tinsley CJ, Fontaine-Palmer NS, Vincent M, Endean EPE, Aggleton JP, Brown MW, Warburton EC. Differing time dependencies of object recognition memory impairments produced by nicotinic and muscarinic cholinergic antagonism in perirhinal cortex. Learn Mem 2011; 18:484-92. [PMID: 21693636 DOI: 10.1101/lm.2274911] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The roles of muscarinic and nicotinic cholinergic receptors in perirhinal cortex in object recognition memory were compared. Rats' discrimination of a novel object preference test (NOP) test was measured after either systemic or local infusion into the perirhinal cortex of the nicotinic receptor antagonist methyllycaconitine (MLA), which targets alpha-7 (α7) amongst other nicotinic receptors or the muscarinic receptor antagonists scopolamine, AFDX-384, and pirenzepine. Methyllycaconitine administered systemically or intraperirhinally before acquisition impaired recognition memory tested after a 24-h, but not a 20-min delay. In contrast, all three muscarinic antagonists produced a similar, unusual pattern of impairment with amnesia after a 20-min delay, but remembrance after a 24-h delay. Thus, the amnesic effects of nicotinic and muscarinic antagonism were doubly dissociated across the 20-min and 24-h delays. The same pattern of shorter-term but not longer-term memory impairment was found for scopolamine whether the object preference test was carried out in a square arena or a Y-maze and whether rats of the Dark Agouti or Lister-hooded strains were used. Coinfusion of MLA and either scopolamine or AFDX-384 produced an impairment profile matching that for MLA. Hence, the antagonists did not act additively when coadministered. These findings establish an important role in recognition memory for both nicotinic and muscarinic cholinergic receptors in perirhinal cortex, and provide a challenge to simple ideas about the role of cholinergic processes in recognition memory: The effects of muscarinic and nicotinic antagonism are neither independent nor additive.
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Affiliation(s)
- Chris J Tinsley
- MRC Centre for Synaptic Plasticity, School of Physiological Sciences, Bristol University, United Kingdom.
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Gilibili RR, Mullangi R, Srinivas NR. Intravenous prediction of human pharmacokinetic parameters for ketorolac, a non-steroidal anti-inflammatory agent, using allometry approach. Eur J Drug Metab Pharmacokinet 2011; 36:87-93. [PMID: 21380569 DOI: 10.1007/s13318-011-0029-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Accepted: 02/16/2011] [Indexed: 11/29/2022]
Abstract
The intravenous pharmacokinetics data of ketorolac in mice, rats, rabbits, dogs and monkeys were assembled from literature. The relationship between the main pharmacokinetic parameters [viz., volume of distribution (V (d)) and clearance (CL)] and body weight was studied across five mammalian species, using double-logarithmic plots to predict the human pharmacokinetic parameters of CL and V (d) using simple allometry or with correction factors [maximum life span potential (MLP), brain weight, CF1 (bile flow/liver weight) and CF2 (bile flow/body weight)]. The metabolism pattern, biotransformation pathways and the predominant urinary excretion of parent and the formed metabolites of ketorolac were found to be similar amongst mice, rats, rabbits, dogs, monkeys and humans, facilitating the scaling process. The human parameter value for V (d) was predicted by simple allometric equation: 0.2481W(1.0549) (r (2) = 0.9217). The predicted V (d) value (21.92 L) is close to the reported value (17.5 L), whereas the CL was predicted by simple allometric approach or with standard correction factors viz., MLP, brain weight, CF1 and CF2. Best proximity CL value was obtained with MLP having allometric equation: 0.7126W(1.3264) (r (2) = 0.9640). The outcome of this exercise suggests that allometric scaling with suitable correction factors could potentially be used to predict the human pharmacokinetic parameters of drugs belonging to non-steroidal anti-inflammatory drugs retrospectively.
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Tsuda Y, Tatami S, Yamamura N, Tadayasu Y, Sarashina A, Liesenfeld KH, Staab A, Schäfer HG, Ieiri I, Higuchi S. Population pharmacokinetics of tamsulosin hydrochloride in paediatric patients with neuropathic and non-neuropathic bladder. Br J Clin Pharmacol 2011; 70:88-101. [PMID: 20642551 DOI: 10.1111/j.1365-2125.2010.03662.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT Tamsulosin is available on prescription as a modified release capsule in the US (Flomax), and in most European countries for the treatment of the signs and symptoms of benign prostatic hyperplasia (BPH). The pharmacokinetics of tamsulosin hydrochloride (HCl) have been extensively studied in adults, but no pharmacokinetic data for paediatrics have been published to date. WHAT THIS STUDY ADDS A population pharmacokinetic model of tamsulosin HCl was developed in paediatric patients. Covariate analysis revealed that body weight and alpha(1)-acid glycoprotein influenced both the apparent clearance and the apparent volume of distribution. This study confirms that there is no major difference in the pharmacokinetics of tamsulosin HCl between paediatrics (age range 2-16 years) and adults when the effect of body weight is taken into consideration. AIMS The main objective of this study was to characterize the population pharmacokinetics of tamsulosin hydrochloride (HCl) in paediatric patients with neuropathic and non-neuropathic bladder. A secondary objective was to compare the pharmacokinetics in paediatric patients and adults. METHODS Tamsulosin HCl plasma concentrations in 1082 plasma samples from 189 paediatric patients (age range 2-16 years) were analyzed with NONMEM, applying a one compartment model with first-order absorption. Based on the principles of allometry, body weight was incorporated in the base model, along with fixed allometric exponents. Covariate analysis was performed by means of a stepwise forward inclusion and backward elimination procedure. Simulations based on the final model were used to compare the pharmacokinetics with those in adults. RESULTS Beside the priori-implemented body weight, only alpha(1)-acid glycoprotein had an effect on both apparent clearance and apparent volume of distribution. No other investigated covariates, including gender, age, race, patient population and concomitant therapy with anti-cholinergics, significantly affected the pharmacokinetics of tamsulosin HCl (P < 0.001). The results of simulations indicated that the exposure in 12.5 kg paediatric patients was 3.5-4.3 fold higher than that in 70.0 kg adults. After a weight-based dose administration, the exposure in paediatric patients was comparable with that in healthy adults. CONCLUSIONS A population pharmacokinetic model of tamsulosin HCl in paediatric patients was established and it described the data well. There was no major difference in the pharmacokinetics of tamsulosin HCl between paediatric patients (age range 2-16 years) and adults when the effect of body weight was taken into consideration.
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Affiliation(s)
- Yasuhiro Tsuda
- Pharmacokinetics and Non-Clinical Safety Department, Nippon Boehringer Ingelheim Co., Ltd, Hyogo, Japan
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Pai MP. Estimating the glomerular filtration rate in obese adult patients for drug dosing. Adv Chronic Kidney Dis 2010; 17:e53-62. [PMID: 20727504 DOI: 10.1053/j.ackd.2010.05.010] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Revised: 05/13/2010] [Accepted: 05/27/2010] [Indexed: 01/08/2023]
Abstract
One-third of adult Americans are currently classified as obese. Physiologic changes associated with obesity can potentially alter the clearance of commonly used drugs. Clearance of certain drugs by the kidneys occurs primarily through glomerular filtration and tubular secretion. Obesity has been associated with glomerular hyperfiltration, whereas obesity-related effects on tubular secretion are not well characterized. Estimation of the glomerular filtration rate (GFR) is currently performed using serum creatinine using the Modification of Diet in Renal Disease (MDRD) equation. However, drug dosing guidelines are often based on creatinine clearance (CLcr) using the Cockcroft-Gault equation as a surrogate of GFR. There is a lack of consensus on the most appropriate method for estimation of GFR or CLcr in patients with obesity. The controversy relates to the use of 2 body size descriptors that confound these equations. The Cockcroft-Gault equation relies on total body weight and so overestimates GFR in patients with obesity. The MDRD equation indexes GFR based on a normalized body surface area, that is, mL/min/1.73 m(2). Conversion of MDRD estimated GFR to non-normalized body surface area overestimates GFR in patients with obesity. The current review explores current approaches and controversies to estimation of GFR and CLcr among obese patients in clinical practice. The role of the alternate body size descriptor, lean body weight to estimate CLcr in obese patients is reviewed.
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Abstract
Aptamers are single-stranded oligonucleotides that fold into defined architectures and bind to targets such as proteins. In binding proteins they often inhibit protein–protein interactions and thereby may elicit therapeutic effects such as antagonism. Aptamers are discovered using SELEX (systematic evolution of ligands by exponential enrichment), a directed in vitro evolution technique in which large libraries of degenerate oligonucleotides are iteratively and alternately partitioned for target binding. They are then amplified enzymatically until functional sequences are identified by the sequencing of cloned individuals. For most therapeutic purposes, aptamers are truncated to reduce synthesis costs, modified at the sugars and capped at their termini to increase nuclease resistance, and conjugated to polyethylene glycol or another entity to reduce renal filtration rates. The first aptamer approved for a therapeutic application was pegaptanib sodium (Macugen; Pfizer/Eyetech), which was approved in 2004 by the US Food and Drug Administration for macular degeneration. Eight other aptamers are currently undergoing clinical evaluation for various haematology, oncology, ocular and inflammatory indications. Aptamers are ultimately chemically synthesized in a readily scalable process in which specific conjugation points are introduced with defined stereochemistry. Unlike some protein therapeutics, aptamers do not elicit antibodies, and because aptamers generally contain sugars modified at their 2′-positions, Toll-like receptor-mediated innate immune responses are also abrogated. As aptamers are oligonucleotides they can be readily assembled into supramolecular multi-component structures using hybridization. Owing to the fact that binding to appropriate cell-surface targets can lead to internalization, aptamers can also be used to deliver therapeutic cargoes such as small interfering RNA. Supramolecular assemblies of aptamers and delivery agents have already been demonstrated in vivo and may pave the way for further therapeutic strategies with this modality in the future.
Aptamers are oligonucleotide sequences that are capable of recognizing target proteins with an affinity and specificity rivalling that of antibodies. In this article, Keefe and colleagues discuss the development, properties and therapeutic potential of aptamers, highlighting those currently in the clinic. Nucleic acid aptamers can be selected from pools of random-sequence oligonucleotides to bind a wide range of biomedically relevant proteins with affinities and specificities that are comparable to antibodies. Aptamers exhibit significant advantages relative to protein therapeutics in terms of size, synthetic accessibility and modification by medicinal chemistry. Despite these properties, aptamers have been slow to reach the marketplace, with only one aptamer-based drug receiving approval so far. A series of aptamers currently in development may change how nucleic acid therapeutics are perceived. It is likely that in the future, aptamers will increasingly find use in concert with other therapeutic molecules and modalities.
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Prediction of the in vitro intrinsic clearance determined in suspensions of human hepatocytes by using artificial neural networks. Eur J Pharm Sci 2010; 39:310-21. [DOI: 10.1016/j.ejps.2009.12.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2009] [Revised: 12/15/2009] [Accepted: 12/20/2009] [Indexed: 11/22/2022]
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Fagerholm U. Prediction of human pharmacokinetics—evaluation of methods for prediction of hepatic metabolic clearance. J Pharm Pharmacol 2010; 59:803-28. [PMID: 17637173 DOI: 10.1211/jpp.59.6.0007] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Abstract
Methods for prediction of hepatic clearance (CLH) in man have been evaluated. A physiologically-based in-vitro to in-vivo (PB-IVIV) method with human unbound fraction in blood (fu,bl) and hepatocyte intrinsic clearance (CLint)-data has a good rationale and appears to give the best predictions (maximum ∼2-fold errors; < 25% errors for half of CL-predictions; appropriate ranking). Inclusion of an empirical scaling factor is, however, needed, and reasons include the use of cryopreserved hepatocytes with low activity, and inappropriate CLint- and fu,bl-estimation methods. Thus, an improvement of this methodology is possible and required. Neglect of fu,bl or incorporation of incubation binding does not seem appropriate. When microsome CLint-data are used with this approach, the CLH is underpredicted by 5- to 9-fold on average, and a 106-fold underprediction (attrition potential) has been observed. The poor performance could probably be related to permeation, binding and low metabolic activity. Inclusion of scaling factors and neglect of fu,bl for basic and neutral compounds improve microsome predictions. The performance is, however, still not satisfactory. Allometry incorrectly assumes that the determinants for CLH relate to body weight and overpredicts human liver blood flow rate. Consequently, allometric methods have poor predictability. Simple allometry has an average overprediction potential, > 2-fold errors for ∼1/3 of predictions, and 140-fold underprediction to 5800-fold overprediction (potential safety risk) range. In-silico methodologies are available, but these need further development. Acceptable prediction errors for compounds with low and high CLH should be ∼50 and ∼10%, respectively. In conclusion, it is recommended that PB-IVIV with human hepatocyte CLint and fu,bl is applied and improved, limits for acceptable errors are decreased, and that animal CLH-studies and allometry are avoided.
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Affiliation(s)
- Urban Fagerholm
- Clinical Pharmacology, AstraZeneca R&D Södertälje, S-151 85 Södertälje, Sweden.
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Musuamba FT, Rousseau A, Bosmans JL, Senessael JJ, Cumps J, Marquet P, Wallemacq P, Verbeeck RK. Limited sampling models and Bayesian estimation for mycophenolic acid area under the curve prediction in stable renal transplant patients co-medicated with ciclosporin or sirolimus. Clin Pharmacokinet 2009; 48:745-58. [PMID: 19817503 DOI: 10.2165/11318060-000000000-00000] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
BACKGROUND AND OBJECTIVE Mycophenolate mofetil is a prodrug of mycophenolic acid (MPA), an immunosuppressive agent used in combination with corticosteroids and calcineurin inhibitors or sirolimus for the prevention of acute rejection after solid organ transplantation. Although MPA has a rather narrow therapeutic window and its pharmacokinetics show considerable intra- and interindividual variability, dosing guidelines recommend a standard dosage regimen of 0.5-1.0 g twice daily in adult renal, liver and cardiac transplant recipients. The main objective of the present study was to develop a method to predict the MPA area under the plasma concentration-time curve during one 12-hour dosing interval (AUC(12)) by using multiple linear regression models and maximum a posteriori (MAP) Bayesian estimation methods in patients co-medicated with ciclosporin or sirolimus, aiming to individualize the dosage regimen of mycophenolate mofetil. PATIENTS AND METHODS Pharmacokinetic profiles of MPA and mycophenolic acid glucuronide (MPAG), the main metabolite of MPA, were obtained from 40 stable adult renal allograft recipients on three different occasions: the day before switching from ciclosporin to sirolimus co-medication (+/-7.4 months post-transplantation; period I) and at 60 days and 270 days after the switch (periods II and III). Blood samples for determination of MPA and MPAG concentrations in plasma were taken at 0 hours (pre-dose) and at 0.33, 0.66, 1.25, 2, 4, 6, 8 and 12 hours after oral intake of mycophenolate mofetil. The MPA AUC(12) was calculated by the trapezoidal method (the observed AUC(12)). Patients were randomly divided into (i) a model-building test group (n = 27); and (ii) a model-validation group (n = 13). Multiple linear regression models were developed, based on three sampling times after drug administration. Subsequently, a population pharmacokinetic model describing MPA and MPAG plasma concentrations was developed using nonlinear mixed-effects modelling and a Bayesian estimator based on the population pharmacokinetic model was used to predict the MPA AUC(12) based on three sampling times taken within 2 hours following dosing. RESULTS Fifty-two percent of the observed AUC(12) values (three periods) in the 40 patients receiving a fixed dose of mycophenolate mofetil 750 mg twice daily were outside the recommended therapeutic range (30-60 microg x h/mL). The failure of the standard dose to yield an AUC(12) value within the therapeutic range was especially pronounced during the first study period. Of the multiple linear regression models that were tested, the equation based on the 0-hour (pre-dose), 0.66- and 2-hour sampling times showed the best predictive performance in the validation group: r2 = 0.79, relative root mean square error (rRMSE) = 14% and mean relative prediction error (MRPE) = 0.9%. The pharmacokinetics of MPA and MPAG were best described by a two-compartment model with first-order absorption and elimination for MPA, plus a compartment for MPAG, also including a gastrointestinal compartment and enterohepatic cycling in the case of sirolimus co-medication. The ratio of aminotransferase liver enzymes (AST and ALT) and the glomerular filtration rate significantly influenced MPA glucuronidation and MPAG renal excretion, respectively. Bayesian estimation of the MPA AUC(12) based on 0-, 1.25- and 2-hour sampling times predicted the observed AUC(12) values of the patients in the validation group, with the following predictive performance characteristics: r2 = 0.93, rRMSE = 12.4% and MRPE = -0.4%. CONCLUSION Use of the developed multiple linear regression equation and Bayesian estimator, both based on only three blood sampling times within 2 hours following a dose of mycophenolate mofetil, allowed an accurate prediction of a patient's MPA AUC(12) for therapeutic drug monitoring and dose individualization. These findings should be validated in a randomized prospective trial.
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Affiliation(s)
- Flora T Musuamba
- School of Pharmacy, Faculty of Medicine, Université Catholique de Louvain, Brussels, Belgium.
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Habtemariam B, Sallas W, Sunkara G, Kern S, Jarugula V, Pillai G. Population pharmacokinetics of valsartan in pediatrics. Drug Metab Pharmacokinet 2009; 24:145-52. [PMID: 19430170 DOI: 10.2133/dmpk.24.145] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The objective of this work was to develop a population pharmacokinetic model to assess the influence of subject covariates on the pharmacokinetics of valsartan in children. Data were collected from a single dose study in 26 hypertensive children ages 1 to 16 years. Subjects received 2 mg/kg valsartan suspension up to a maximum dose of 80 mg. Plasma samples were collected and analyzed using LC/MS/MS. Several structural pharmacokinetic models were evaluated for appropriateness. Allometric scaling and standard covariate analyses were performed to explain interindividual variabilities. Objective function values and goodness of fit plots were used for model selection. A posterior predictive check was used for model evaluation. A linear 2-compartment first-order elimination model with zero-order absorption and lag-time best described the disposition of valsartan. Allometric scaling and standard covariate analysis revealed that age and body size have similar influence; however, after adjustment for body size using fat free mass (FFM), the effect of increasing age was no longer significant on valsartan clearance (2% per year relative to a typical 8 year old with FFM of 30 kg). The population pharmacokinetic model reveals that increase in age has minimal influence on body size dependent clearance of valsartan in children.
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Shimamura K, Wajima T, Yano Y. Pharmacokinetic prediction for intravenous β‐lactam antibiotics in pediatric patients. J Pharm Sci 2007; 96:3125-39. [PMID: 17722099 DOI: 10.1002/jps.20977] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A method for predicting pharmacokinetics in pediatric patients for intravenous beta-lactam antibiotics is proposed. We focused on the allometric relationships of pharmacokinetic parameters with individual body weights (BW) in human including healthy adults and pediatric patients. Drug concentration data for 15 intravenous beta-lactam antibiotics were collected retrospectively from the published articles and the individual pharmacokinetic parameters were re-calculated. A mixed effect modeling (MEM) was applied for the allometric relationship for those beta-lactam antibiotics, and mean and variances of inter-drug variability for the allometric parameters and also variance for intra-drug (residual) variability were estimated. Then drug-specific allometric parameters were estimated by an empirical Bayesian method using the pharmacokinetic parameters for a drug only in healthy adults as observations, and finally the individual pharmacokinetic parameters in pediatric patients were predicted. The predictability of the method was evaluated by the leave-one-out method. We also demonstrated a method for simulating plasma concentration-time profiles in pediatric patients, and the predicted time-course curves generally coincided well with the actual plasma concentration data for the tested drugs.
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Affiliation(s)
- Kenji Shimamura
- Biostatistics Department, Shionogi & Co., Ltd. Sagisu 5-12-4, Osaka 553-0002, Japan
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Abstract
Growth and development can be investigated using readily observable demographic factors such as weight and age. Size is the primary covariate and can be referenced to a 70-kg person with allometry using a coefficient of 0.75 for clearance and 1 for volume. The use of these coefficients is supported by fractal geometric concepts and observations from diverse areas in biology. Fat free mass (FFM) might be expected to do better than total body weight when there are wide variations in fat affecting body composition. Clearance pathways develop in the fetus before birth. The use of postnatal age as a descriptor of maturation is unsatisfactory because birth may occur prematurely; therefore postmenstrual age is a superior predictor of elimination function. A sigmoid E(max) model (Hill equation) describes gradual maturation of clearance in early life leading to a mature adult clearance achieved at a later age.
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Affiliation(s)
- B J Anderson
- Department of Anaesthesiology, University of Auckland School of Medicine, Auckland, New Zealand.
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Martinez M, Mahmood I, Hunter RP. Interspecies allometric scaling: prediction of clearance in large animal species: Part II: mathematical considerations. J Vet Pharmacol Ther 2006; 29:425-32. [PMID: 16958788 DOI: 10.1111/j.1365-2885.2006.00787.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Interspecies scaling is a useful tool for the prediction of pharmacokinetic parameters from animals to humans, and it is often used for estimating a first-time in human dose. However, it is important to appreciate the mathematical underpinnings of this scaling procedure when using it to predict pharmacokinetic parameter values across animal species. When cautiously applied, allometry can be a tool for estimating clearance in veterinary species for the purpose of dosage selection. It is particularly valuable during the selection of dosages in large zoo animal species, such as elephants, large cats and camels, for which pharmacokinetic data are scant. In Part I, allometric predictions of clearance in large animal species were found to pose substantially greater risks of inaccuracies when compared with that observed for humans. In this report, we examine the factors influencing the accuracy of our clearance estimates from the perspective of the relationship between prediction error and such variables as the distribution of body weight values used in the regression analysis, the influence of a particular observation on the clearance estimate, and the 'goodness of fit' (R(2)) of the regression line. Ultimately, these considerations are used to generate recommendations regarding the data to be included in the allometric prediction of clearance in large animal species.
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Affiliation(s)
- M Martinez
- Division of Therapeutic Drugs for Food Animals (HFV-130), Office of New Animal Drug Evaluation, Center for Veterinary Medicine, Food & Drug Administration, Rockville, MD 20855, USA.
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Ferl GZ, Kenanova V, Wu AM, DiStefano JJ. A two-tiered physiologically based model for dually labeled single-chain Fv-Fc antibody fragments. Mol Cancer Ther 2006; 5:1550-8. [PMID: 16818514 DOI: 10.1158/1535-7163.mct-06-0072] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Monoclonal antibodies (mAb) are being used at an increasing rate in the treatment of cancer, with current efforts focused on developing engineered antibodies that exhibit optimal biodistribution profiles for imaging and/or radioimmunotherapy. We recently developed the single-chain Fv-Fc (scFv-Fc) mAb, which consists of a single-chain antibody Fv fragment (light-chain and heavy-chain variable domains) coupled to the IgG1 Fc region. Point mutations that attenuate binding affinity to FcRn were introduced into the Fc region of the wild-type scFv-Fc mAb, resulting in several new antibodies, each with a different half-life. Here, we describe the construction of a two-tiered physiologically based pharmacokinetic model capable of simulating the apparent biodistribution of both (111)In- and (125)I-labeled scFv-Fc mAbs, where (111)In-labeled metabolites from degraded (111)In-labeled mAbs tend to become trapped within the lysosomal compartment, whereas free (125)I from degraded (125)I-labeled mAbs is quickly eliminated via the urinary pathway. The different concentration-time profiles of (111)In- and (125)I-labeled mAbs permits estimation of the degradation capacity of each organ and elucidates the dependence of cumulative degradation in liver, muscle, and skin on FcRn affinity and tumor mass. Liver is estimated to account for approximately 50% of all degraded mAb when tumor is small (approximately 0.1 g) and drops to about 35% when tumor mass is larger (approximately 0.3 g). mAb degradation in residual carcass (primarily skin and muscle) decreases from approximately 45% to 16% as FcRn affinity of the three mAb variants under consideration increases. In addition, elimination of a small amount of mAb in the kidneys is shown to be required for a successful fit of model to data.
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Affiliation(s)
- Gregory Z Ferl
- Department of Computer Science, University of California, Los Angeles, USA.
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Crommentuyn KML, Scherpbier HJ, Kuijpers TW, Mathôt RAA, Huitema ADR, Beijnen JH. Population pharmacokinetics and pharmacodynamics of nelfinavir and its active metabolite M8 in HIV-1-infected children. Pediatr Infect Dis J 2006; 25:538-43. [PMID: 16732153 DOI: 10.1097/01.inf.0000215242.70300.95] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND The objectives of this study are to develop and validate a population pharmacokinetic model that adequately describes the pharmacokinetics of nelfinavir and its active metabolite M8 in HIV-1-infected children; to define factors involved in the pharmacokinetic variability, which could aid in defining dosing strategies; and to correlate the pharmacokinetics to the treatment response. METHODS Protease inhibitor-naive, HIV-1-infected children were included. A population pharmacokinetic model of nelfinavir and M8 was developed using NONMEM. Bayesian analysis was used to estimate pharmacokinetic values. A pharmacokinetic-pharmacodynamic analysis was performed to study relationships between these values and the virologic response to therapy. RESULTS From 38 children, 724 nelfinavir and 636 M8 plasma concentrations were available. The pharmacokinetics of both compounds were described simultaneously with a one-compartment model with first-order elimination. Clearance (CL/F) and volume of distribution (V/F) were 32.6 L/h (interindividual variability [IIV]: 31.6%) and 281 L/h (IIV: 29.7%) for nelfinavir and 86.2 L/h (IIV: 43.1%) and 42.3 L/h for M8. No factors could be defined that affected the pharmacokinetics of nelfinavir or M8. The overall virologic response was 78% (HIV-1 RNA <500 copies/mL, on-treatment analysis). No differences in exposure to nelfinavir and M8 were observed between responders and nonresponders. The only factor distinguishing the two groups was a higher baseline HIV-1 RNA concentration in nonresponders. CONCLUSION A model was developed and validated that adequately described the population pharmacokinetics of nelfinavir and M8 in a childhood population. No factors affecting dosing strategies were identified, and no correlation could be demonstrated between the exposure to nelfinavir and M8 and the virologic treatment response.
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McKerchar TL, Fowler SC. Dissimilar effects of subchronic clozapine and haloperidol on operant lever pressing in C57BL/6J, BALB/cJ, and LP/J mice. Behav Pharmacol 2005; 16:585-9. [PMID: 16170236 DOI: 10.1097/01.fbp.0000181592.63125.bc] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The effects of the atypical antipsychotic, clozapine, and the typical antipsychotic, haloperidol, on operant behavior have been well described in the rat; however, little such work has been done with mice. In the present study, the effects of clozapine (2.0, 4.0, and 6.0 mg/kg) and haloperidol (0.06, 0.13, and 0.25 mg/kg) were evaluated in three inbred strains of mice (C57BL/6J, BALB/cJ, and LP/J mice) across six consecutive daily sessions at each dose, in which each lever press produced access to milk. Tolerance to the rate-reducing effects of clozapine was observed in the BALB/cJ strain, but not in the C57BL/6J and LP/J strains. In contrast, sensitization was observed in the three mouse strains treated with subchronic haloperidol. These results are at odds with the operant rat literature on the effects of clozapine, but are consistent with the idea that genetic variables contribute, at least in part, to some of the differences observed in response to antipsychotics.
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Affiliation(s)
- T L McKerchar
- Department of Pharmacology and Toxicology, University of Kansas, KS 66045-2505, USA
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