| 1. |
- Back, Hyun-moon, et al.
(författare)
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A mechanism-based pharmacokinetic model of fenofibrate for explaining increased drug absorption after food consumption
- 2018
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Ingår i: BMC Pharmacology & Toxicology. - : BIOMED CENTRAL LTD. - 2050-6511. ; 19
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Tidskriftsartikel (refereegranskat)abstract
- Background: Oral administration of drugs is convenient and shows good compliance but it can be affected by many factors in the gastrointestinal (GI) system. Consumption of food is one of the major factors affecting the GI system and consequently the absorption of drugs. The aim of this study was to develop a mechanistic GI absorption model for explaining the effect of food on fenofibrate pharmacokinetics (PK), focusing on the food type and calorie content.Methods: Clinical data from a fenofibrate PK study involving three different conditions (fasting, standard meals and high-fat meals) were used. The model was developed by nonlinear mixed effect modeling method. Both linear and nonlinear effects were evaluated to explain the impact of food intake on drug absorption. Similarly, to explain changes in gastric emptying time for the drug due to food effects was evaluated.Results: The gastric emptying rate increased by 61.7% during the first 6.94 h after food consumption. Increased calories in the duodenum increased the absorption rate constant of the drug in fed conditions (standard meal = 16.5%, high-fat meal = 21.8%) compared with fasted condition. The final model displayed good prediction power and precision.Conclusions: A mechanistic GI absorption model for quantitatively evaluating the effects of food on fenofibrate absorption was successfully developed, and acceptable parameters were obtained. The mechanism-based PK model of fenofibrate can quantify the effects of food on drug absorption by food type and calorie content.
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| 2. |
- Chae, Jung-woo, et al.
(författare)
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A simple pharmacokinetic model of alendronate developed using plasma concentration and urine excretion data from healthy men
- 2014
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Ingår i: Drug Development and Industrial Pharmacy. - : Informa UK Limited. - 0363-9045 .- 1520-5762. ; 40:10, s. 1325-1329
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Tidskriftsartikel (refereegranskat)abstract
- The study of pharmacokinetics of alendronate has been hampered by difficulties in accurately and reproducibly determining their concentrations in serum and urine. Thus, pharmacokinetic characteristics of alendronate have been described in many reports based on urinary excretion data; and plasma pharmacokinetics and the simultaneous pharmacokinetic models of alendronate in plasma and urine are not available. The aims of this study were to measure alendronate concentration in plasma and excretion in urine concurrently and to develop compartmental pharmacokinetic model using urine data. In open-label, single-dose pharmacokinetic study, 10 healthy male volunteers received oral dose of alendronate (70mg tablet). Blood and urine alendronate concentrations were determined using validated high-performance liquid chromatography method. Non-compartmental analysis was performed using WinNonlin program (Pharsight Inc., Apex, NC). A one-compartment pharmacokinetic model was applied to describe pharmacokinetics of alendronate. A peak plasma alendronate concentration of 33.10 +/- 14.32 ng/mL was attained after 1.00 +/- 0.16 h. The cumulative amount of alendronate excreted in urine and peak excretion rate were 731.28 +/- 654.57 mu g and 314.68 +/- 395.43 mg/h, respectively. The model, which included first-order absorption rate for oral dosing, showed good fit to alendronate data obtained from plasma and urine. The absorption rate constant was 2.68 +/- 0.95 h(-1). The elimination rate constants K-urine and Knon-ur were 0.005 +/- 0.004 h(-1) and 0.42 +/- 0.08 h(-1), respectively. The pharmacokinetics of alendronate in plasma and urine of healthy men can be predicted using one-compartment model, and thus the behavior of drug in plasma can be estimated from urinary excretion data.
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| 3. |
- Chae, Jung-woo, et al.
(författare)
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BSA and ABCB1 polymorphism affect the pharmacokinetics of sunitinib and its active metabolite in Asian mRCC patients receiving an attenuated sunitinib dosing regimen
- 2016
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Ingår i: Cancer Chemotherapy and Pharmacology. - : Springer Science and Business Media LLC. - 0344-5704 .- 1432-0843. ; 78:3, s. 623-632
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Tidskriftsartikel (refereegranskat)abstract
- An attenuated dosing (AD) sunitinib regimen of 37.5 mg daily has been suggested to reduce the toxicity reported with the standard dosing regimen to metastatic renal cell carcinoma (mRCC) patients. The aim of this study was to characterize the population pharmacokinetic (PK) properties of sunitinib and SU12662, the active metabolite, in patients receiving the AD regimen and to ascertain significant covariates influencing PK parameters. Thirty-one mRCC patients receiving AD sunitinib regimen were included. Plasma samples were collected on day 29 of each treatment cycle after the start of the therapy. Nonlinear mixed-effects modeling was applied to estimate the population PK properties of sunitinib and SU12662 as well as the effect of covariates on PK parameters. Monte Carlo simulation was also performed to predict the total trough level (TTL) of sunitinib and SU12662. Sunitinib population means for CL/F and V (d) /F (central) were 13.8 L/h and 1720 L, respectively. SU12662 population means for CL/F and V (d) /F were 42.1 L/h and 1410 L, respectively. Body surface area (BSA) and ABCB1 polymorphism significantly influenced the CL/F variability of sunitinib: CL/F (parent) = 13.8 x exp((BSA - 1.75) x 2.08 + (ABCB1 (genotype) - 0.67) x 0.61), ABCB1-0: wild genotype, 1: mutant genotype. The effect size of ABCB1 mutant genotype and BSA greater than 1.75 m(2) in relation to sunitinib clearance was 31.14 % (p = 0.006) and 22.11 % (p = 0.011), respectively, relative to the reference group. Adjusting doses of sunitinib according to BSA and ABCB1 polymorphism in Asian mRCC patients may be recommended for sufficient attainment of a target TTL of sunitinib and its metabolite.
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| 4. |
- Kim, In-Wha, et al.
(författare)
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Population pharmacokinetics analysis of cyclophosphamide with genetic effects in patients undergoing hematopoietic stem cell transplantation
- 2013
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Ingår i: European Journal of Clinical Pharmacology. - : Springer Science and Business Media LLC. - 0031-6970 .- 1432-1041. ; 69:8, s. 1543-1551
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Tidskriftsartikel (refereegranskat)abstract
- To build a population pharmacokinetic (PK) model of cyclophosphamide (CY) and its metabolite, 4-hydroxycyclophosphamide (HCY), in patients undergoing allogeneic haematopoietic stem cell transplantation (HSCT) and to identify covariates, including genetic polymorphisms, which affect CY and HCY PK parameters. The study cohort comprised 21 patients undergoing HSCT who received CY intravenously between 2009 and 2011. Clinical characteristics and CY and HCY concentration data were collected for all patients, and ABCB1, ABCC2, GSTA1, GSTM1, GSTP1, GSTT1, CYP2B6, CYP2C19, and CYP3A5 genotyping was performed. A hypothetical enzyme compartment was conducted using the NONMEM program. A population PK analysis showed that the ABCC2 1249 genotype and aspartate aminotransferase levels significantly affected non-induced clearance (CL (UI)) and induced clearance (CL (I)) of CY, respectively. The final estimate of the mean CL (UI) and CL (I) of CY was 15.5 and 0.683 L/h, respectively, and the mean volume of distribution (V (1)) of CY was 88.0 L. The inter-individual variability for CL (UI), CL (I), and V (1) of CY was 52.8, 200, and 18.0 %, respectively. Additionally, the CL (UI) of CY was significantly decreased to approximately 51 % in patients with the 1249 GA heterozygous genotype compared to those with the 1249 GG wild-type genotype (p < 0.05). There were only three heterozygous GA variants of ABCC2 1249 in the study patients. The population PK model developed in this study implies an influence of genetic factors on the clearance of CY. Clearance was moderately reduced in patients with the ABCC2 1249GA heterozygous genotype.
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