scholarly journals Identification of Mechanism and Pathway of the Interaction between the African Traditional Medicine, Sutherlandia Frutescens, and the Antiretroviral Protease Inhibitor, Atazanavir, in Human Subjects Using Population Pharmacokinetic (PK) Analysis

2018 ◽  
Vol 21 (1s) ◽  
pp. 215s-221s ◽  
Author(s):  
Adrienne Carmel Muller ◽  
Murray P Ducharme ◽  
Isadore Kanfer
Keyword(s):  
Small Intestine ◽  
Protease Inhibitor ◽  
Human Subjects ◽  
Compartmental Analysis ◽  
Compartment Model ◽  
Population Pharmacokinetic ◽  
Absorption Mechanism ◽  
Population Pk ◽  
Before And After ◽  
Sutherlandia Frutescens

Although the use of the indigenous Southern African plant, Sutherlandia frutescens (SF) for the treatment of HIV/AIDS has previously been described, the risk which it may pose to the safety and efficacy of ARVs and the potential mechanisms which underlie such effects may have clinical significance and relevance. The protease inhibitor (PI), atazanavir (ATV) is a substrate of the efflux transporter, P-gp which modulates absorption in the small intestine, as well as CYP3A4 and CYP3A5enzymes which facilitate metabolism in the small intestine and liver. The objective of this study was to investigate the effect of SF on the pharmacokinetics (PK) of atazanavir (ATV) and to use a population PK analysis to fit and explain plasma concentration vs. time profiles of ATV generated in a previously conducted study in healthy male subjects in order to understand and postulate on the potential mechanism(s) of the drug-drug interaction. The population PK Compartmental Analysis of ATV before and after a two-week regimen of Phyto Nova Sutherlandia SU1 tablets which contain SF plant material indicated that a two compartment model with a dual absorption mechanism best explained the data. The dual absorption mechanism is hypothesized to reflect “passive” (first-order, Ka parameter) and “active” (zero-order, K0 parameter) absorption processes. The model suggested that the mechanism by which SF reduced the overall bioavailability of ATV may be modulated via the inhibition of the “active” absorption process. This study has highlighted the utility of population PK analyses in postulating probable mechanism(s) whereby an ATM or a herbal medicine interacts with an allopathic drug.

scholarly journals Evaluation of the Adequacy of WHO Revised Dosages of the First-Line Antituberculosis Drugs in Children with Tuberculosis Using Population Pharmacokinetic Modeling and Simulations

2018 ◽  
Vol 62 (9) ◽  
Author(s):  
Yasuhiro Horita ◽  
Abdullah Alsultan ◽  
Awewura Kwara ◽  
Sampson Antwi ◽  
Antony Enimil ◽  
...  
Keyword(s):  
Compartment Model ◽  
World Health ◽  
Population Pharmacokinetic ◽  
Optimal Dosage ◽  
Nonlinear Mixed Effects Models ◽  
First Line ◽  
Time Curve ◽  
Drug Concentrations ◽  
Target Values ◽  
Population Pk

ABSTRACTOptimal doses for antituberculosis (anti-TB) drugs in children have yet to be established. In 2010, the World Health Organization (WHO) recommended revised dosages of the first-line anti-TB drugs for children. Pharmacokinetic (PK) studies that investigated the adequacy of the WHO revised dosages to date have yielded conflicting results. We performed population PK modeling using data from one of these studies to identify optimal dosage ranges. Ghanaian children with tuberculosis on recommended therapy with rifampin (RIF), isoniazid (INH), pyrazinamide (PZA), and ethambutol (EMB) for at least 4 weeks had blood samples collected predose and at 1, 2, 4, and 8 hours postdose. Drug concentrations were determined by validated liquid chromatography-mass spectrometry methods. Nonlinear mixed-effects models were applied to describe the population PK of those drugs using MonolixSuite2016R1 (Lixoft, France). Bayesian estimation was performed, the correlation coefficient, bias, and precision between the observed and predicted areas under the concentration-time curve (AUCs) were calculated, and Bland-Altman plots were analyzed. The population PK of RIF and PZA was described by a one-compartment model and that for INH and EMB by a two-compartment model. Plasma maximum concentration (Cmax) and AUC targets were based on published results for children from India. The lowest target values for pediatric TB patients were attainable at the WHO-recommended dosage schedule for RIF and INH, except forN-acetyltransferase 2 non-slow acetylators (rapid and intermediate acetylators) in the lower-weight bands. However, higher published adult targets were not attainable for RIF and INH. The targets were not achieved for PZA and EMB. (This study has been registered at ClinicalTrials.gov under identifier NCT01687504.)

scholarly journals Population Pharmacokinetic Modelling and Simulation to Determine the Optimal Dose of Nanoparticulated Sorafenib to the Reference Sorafenib

Pharmaceutics ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 629
Author(s):  
Ki Young Huh ◽  
Sejung Hwang ◽  
Sang Yeob Park ◽  
Hye Jung Lim ◽  
Miryung Jin ◽  
...  
Keyword(s):  
Compartmental Analysis ◽  
Optimal Dose ◽  
Compartment Model ◽  
Population Pharmacokinetic ◽  
Open Label ◽  
Post Dose ◽  
Multikinase Inhibitor ◽  
Final Model ◽  
Fasted State ◽  
Second Period

Sorafenib, an oral multikinase inhibitor, exhibits a highly variable absorption profile due to enterohepatic reabsorption and poor solubility. SYO-1644 improved the solubility of sorafenib by nanoparticulation technology leading to enhanced bioavailability. To evaluate the pharmacokinetically equivalent dose of SYO-1644 to the reference Nexavar® 200 mg, a randomized, open-label, replicated two-period study was conducted in healthy volunteers. A total of 32 subjects orally received a single dose of the following assigned treatment under a fasted state in the first period and repeated once more in the second period with a two-week washout: SYO-1644 100, 150 and 200 mg and Nexavar® 200 mg. Pharmacokinetic (PK) samples were collected up to 168 h post-dose. The PK profile was evaluated by both non-compartmental analysis and population PK method. With the final model, 2 × 2 crossover trial scenarios with Nexavar® 200 mg and each dose of SYO-1644 ranging from 100 to 150 mg were repeated 500 times by Monte Carlo simulation, and the proportion of bioequivalence achievement was assessed. Transit absorption compartments, followed by a one-compartment model with first-order elimination and enterohepatic reabsorption components were selected as the final model. The simulation results demonstrated that the SYO-1644 dose between 120 and 125 mg could yielded the highest proportion of bioequivalence.

scholarly journals Application of Pharmacometrics in Pharmacotherapy: Open-Source Software for Vancomycin Therapeutic Drug Management

Pharmaceutics ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 224 ◽  
Author(s):  
Soo Hyeon Bae ◽  
Dong-Seok Yim ◽  
Hyemi Lee ◽  
Ae-Ryoung Park ◽  
Ji-Eun Kwon ◽  
...  
Keyword(s):  
Open Source ◽  
Open Source Software ◽  
Compartment Model ◽  
Therapeutic Drug ◽  
Peripheral Compartment ◽  
Population Pharmacokinetic ◽  
Drug Management ◽  
Korean Patients ◽  
Population Pk ◽  
R Shiny

The population pharmacokinetic (PK) parameters that are implemented in therapeutic drug management (TDM) software were generally obtained from a Western population and might not be adequate for PK prediction with a Korean population. This study aimed to develop a population PK model for vancomycin using Korean data to improve the quality of TDM for Korean patients. A total of 220 patients (1020 observations) who received vancomycin TDM services were included in the dataset. A population PK analysis was performed using non-linear mixed effects modeling, and a covariate evaluation was conducted. A two-compartment model with first-order elimination best explained the vancomycin PK, with estimates of 2.82 L/h, 31.8 L, 11.7 L/h, and 75.4 L for CL, V1, Q, and V2, respectively. In the covariate analysis, weight correlated with the volume of the peripheral compartment, and creatinine clearance, hemodialysis, and continuous renal replacement therapy treatments contributed to the clearance of vancomycin. The results show the clear need to optimize the PK parameters used for TDM in Korean patients. Specifically, V1 should be smaller for Korean patients, and renal replacement therapies should be considered in TDM practice. This final model was successfully applied in R shiny as open-source software for Koreans.

scholarly journals Population Pharmacokinetic Analyses for BC-3781 Using Phase 2 Data from Patients with Acute Bacterial Skin and Skin Structure Infections

2014 ◽  
Vol 59 (1) ◽  
pp. 282-288 ◽  
Author(s):  
C. M. Rubino ◽  
B. Xue ◽  
S. M. Bhavnani ◽  
W. T. Prince ◽  
Z. Ivezic-Schoenfeld ◽  
...  
Keyword(s):  
Renal Function ◽  
Body Size ◽  
Phase 1 ◽  
Compartment Model ◽  
Volume Of Distribution ◽  
Population Pharmacokinetic ◽  
Phase 2 ◽  
Data Set ◽  
Skin Structure ◽  
Population Pk

ABSTRACTBC-3781, a pleuromutilin antimicrobial agent, is being developed for the treatment of patients with acute bacterial skin and skin structure infections (ABSSSI) and community-acquired bacterial pneumonia. Data from a phase 2 study of patients with ABSSSI were used to refine a previous population pharmacokinetic (PK) model and explore potential predictors of PK variability. The previously derived population PK model based on data from three phase 1 studies was applied to sparse sampling data from a phase 2 ABSSSI study and modified as necessary. Covariate analyses were conducted to identify descriptors (e.g., body size, renal function, age) associated with interindividual variability in PK. All population PK analyses were conducted by using Monte Carlo parametric expectation maximization implemented in S-ADAPT 1.5.6. The population PK data set contained 1,167 concentrations from 129 patients; 95% of the patients had 5 or more PK samples (median, 11). The previous population PK model (three-compartment model with first-order elimination and nonlinear protein binding) provided an acceptable and unbiased fit to the data from the 129 patients. Population PK parameters were estimated with acceptable precision; individual clearance values were particularly well estimated (median individual precision of 9.15%). Graphical covariate evaluations showed no relationships between PK and age or renal function but modest relationships between body size and clearance and volume of distribution, which were not statistically significant when included in the population PK model. This population PK model will be useful for subsequent PK-pharmacodynamic analyses and simulations conducted to support phase 3 dose selection. (This study has been registered at ClinicalTrials.gov under registration no. NCT01119105.)

scholarly journals 1540. A Population Pharmacokinetic Model for Vancomycin in Korean Patients Receiving Extracorporeal Membrane Oxygenation Therapy: A Prospective Study

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S562-S562
Author(s):  
Younghee Jung ◽  
Dong-Hwan Lee ◽  
Hyoung Soo Kim
Keyword(s):  
Extracorporeal Membrane Oxygenation ◽  
Creatinine Clearance ◽  
Compartment Model ◽  
Volume Of Distribution ◽  
Population Pharmacokinetic ◽  
Test Model ◽  
Mixed Effect ◽  
Korean Patients ◽  
Membrane Oxygenation ◽  
Population Pk

Abstract Background There is no literature on population pharmacokinetics (PK) of vancomycin in Korean patients receiving extracorporeal membrane oxygenation (ECMO) therapy. The aim of this study was to develop a population PK model for vancomycin in Korean ECMO patients. Methods We prospectively enrolled adult patients who were undergoing ECMO and receiving vancomycin from July 2018 to April 2019. After initial dose of vancomycin was administrated, serial blood samples (seven to nine times per patient) were drawn before the next dose. A population PK model for vancomycin was developed using a nonlinear mixed-effect modeling. Age, sex, creatinine clearance, and body weight were tested as potential covariates in the model. Model selection was based on log-likelihood test, model diagnostic plots, and clinical plausibility. Results Fourteen patients were included over the period. Ten received venovenous, three venoarterial, and one both type ECMO. Eleven were men and the median age was 54 (interquartile range 45–66.3). Mean estimated glomerular filtration rate (eGFR) was 69 ± 46 mL/minute/1.73m2 by the modification of diet in renal disease equation. A total of 123 vancomycin concentrations from the patients were included in the analysis. The population PK of vancomycin was best described by a two-compartment model with a proportional residual error model. The typical value (%between-subject variability) for total clearance was estimated to be 4.33 L/h (21.6%), central volume of distribution was 9.22 L, the intercompartmental clearance was 10.75 L/hr (34.9%) and the peripheral volume of distribution was 19.6 L (26.6%). The proportional residual variability was 8.81%. Creatinine clearance significantly influenced vancomycin clearance (CL). The proposed equation to estimate vancomycin clearance in Korean ECMO patients was CL = 4.33 + 0.199 × (eGFR – 56). Conclusion A two-compartment population PK model successfully describes vancomycin PK profiles in Korean ECMO patients. The model could be used to optimize the dosing regimen if more data become available from currently ongoing clinical study. Disclosures All authors: No reported disclosures.

scholarly journals Optimizing Ceftobiprole Dosage in Pediatric Patients: A Model-Based Approach

2021 ◽  
Author(s):  
Christopher M. Rubino ◽  
Anthony P. Cammarata ◽  
Anne Smits ◽  
Sebastian Schröpf ◽  
Mark Polak ◽  
...  
Keyword(s):  
Pediatric Patients ◽  
Plasma Concentrations ◽  
Compartment Model ◽  
Generation Cephalosporin ◽  
Population Pharmacokinetic ◽  
Model Based ◽  
Final Population ◽  
Pediatric Study ◽  
Population Pk ◽  
Neonates And Infants

Ceftobiprole is an advanced-generation cephalosporin for intravenous administration with activity against Gram-positive and Gram-negative organisms. A population pharmacokinetic (PK) model characterizing the disposition of ceftobiprole in plasma using data from patients in three pediatric studies was developed. Model-based simulations were subsequently performed to assist in dose optimization for the treatment of pediatric patients with hospital-acquired or community-acquired pneumonia. The population PK dataset comprised 518 ceftobiprole plasma concentrations from 107 patients aged 0 (birth) to 17 years. Ceftobiprole PK was well described by a three-compartment model with linear elimination. Ceftobiprole clearance was modeled as a function of glomerular filtration rate; other PK parameters were scaled to body weight. The final population PK model provided a robust and reliable description of the PK of ceftobiprole in the pediatric study population. Model-based simulations using the final model suggested that a ceftobiprole dose of 15 mg/kg infused over 2 hours and administered every 12 hours in neonates and infants <3 months or every 8 hours in older pediatric patients would result in a ceftobiprole exposure consistent with that in adults and good pharmacokinetic-pharmacodynamic target attainment. The dose should be reduced to 10 mg/kg every 12 hours in neonates and infants <3 months who weigh <4 kg to avoid high exposures. Extended intervals and reduced doses may be required for pediatric patients older than 3 months of age with renal impairment.

scholarly journals Target attainment of extended-interval dosing of tobramycin in patients less than five years of age with cystic fibrosis: A pharmacokinetic analysis.

2022 ◽  
Author(s):  
Kevin J Downes ◽  
Austyn Grim ◽  
Laura Shanley ◽  
Ronald C Rubenstein ◽  
Athena F Zuppa ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Young Patients ◽  
Therapeutic Targets ◽  
Compartment Model ◽  
Simulated Patients ◽  
Pharmacokinetic Analysis ◽  
Population Pharmacokinetic ◽  
Once Daily ◽  
Therapeutic Goals ◽  
Population Pk

Background: Extended interval dosing (EID) of tobramycin is recommended for treatment of pulmonary exacerbations in adults and older children with cystic fibrosis (CF), but data are limited in patients less than 5 years of age.Methods:We performed a retrospective population pharmacokinetic (PK) analysis of hospitalized children with CF <5 years of age prescribed intravenous tobramycin for a pulmonary exacerbation from March 2011 to September 2018 at our hospital. Children with normal renal function who had ≥1 tobramycin concentration available were included. Nonlinear mixed effects population PK modeling was performed using NONMEM® using data from the first 48 hours of tobramycin treatment. Monte Carlo simulations were implemented to determine the fraction of simulated patients that met published therapeutic targets with regimens of 10-15 mg/kg/day once daily dosing. Results:Fifty-eight patients received 111 tobramycin courses (range 1-9/patient). A 2-compartment model best described the data. Age, glomerular filtration rate, and vancomycin coadministration were significant covariates on tobramycin clearance. The typical values of clearance and central volume of distribution were 0.252 L/hr/kg^0.75 and 0.308 L/kg, respectively. No once daily regimens achieved all pre-specified targets simultaneously in >75% of simulated subjects. A dosage of 13 mg/kg/dose best met the predefined targets of Cmax >25 mg/L and AUC24 of 80-120 mg*h/L.Conclusions:Based on our population PK analysis and simulations, once daily dosing of tobramycin would not achieve all therapeutic goals in young patients with CF. However, extended-interval dosing regimens may attain therapeutic targets in the majority of young patients.

scholarly journals Optimization of flucloxacillin dosing regimens in critically ill patients using population pharmacokinetic modelling of total and unbound concentrations

2020 ◽  
Vol 75 (9) ◽  
pp. 2641-2649
Author(s):  
Nynke G L Jager ◽  
Reinier M van Hest ◽  
Jiao Xie ◽  
Gloria Wong ◽  
Marta Ulldemolins ◽  
...  
Keyword(s):  
Protein Binding ◽  
Critically Ill ◽  
Critically Ill Patients ◽  
Binding Capacity ◽  
Compartment Model ◽  
Therapeutic Drug ◽  
Population Pharmacokinetic ◽  
Population Pk ◽  
Non Linear ◽  
Dosing Regimens

Abstract Background Initial appropriate anti-infective therapy is associated with improved outcomes in patients with severe infections. In critically ill patients, altered pharmacokinetic (PK) behaviour is common and known to influence the achievement of PK/pharmacodynamic targets. Objectives To describe population PK and optimized dosing regimens for flucloxacillin in critically ill patients. Methods First, we developed a population PK model, estimated between-patient variability (BPV) and identified covariates that could explain BPV through non-linear mixed-effects analysis, using total and unbound concentrations obtained from 35 adult critically ill patients treated with intermittent flucloxacillin. Second, we validated the model using external datasets from two different countries. Finally, frequently prescribed dosing regimens were evaluated using Monte Carlo simulations. Results A two-compartment model with non-linear protein binding was developed and validated. BPV of the maximum binding capacity decreased from 42.2% to 30.4% and BPV of unbound clearance decreased from 88.1% to 71.6% upon inclusion of serum albumin concentrations and estimated glomerular filtration rate (eGFR; by CKD-EPI equation), respectively. PTA (target of 100%fT&gt;MIC) was 91% for patients with eGFR of 33 mL/min and 1 g q6h, 87% for patients with eGFR of 96 mL/min and 2 g q4h and 71% for patients with eGFR of 153 mL/min and 2 g q4h. Conclusions For patients with high creatinine clearance who are infected with moderately susceptible pathogens, therapeutic drug monitoring is advised since there is a risk of underexposure to flucloxacillin. Due to the non-linear protein binding of flucloxacillin and the high prevalence of hypoalbuminaemia in critically ill patients, dose adjustments should be based on unbound concentrations.

scholarly journals Population Pharmacokinetics of Caspofungin among Extracorporeal Membrane Oxygenation Patients during the Postoperative Period of Lung Transplantation

2020 ◽  
Vol 64 (11) ◽  
Author(s):  
Qianlin Wang ◽  
Zhu Zhang ◽  
Donglin Liu ◽  
Wenqian Chen ◽  
Gang Cui ◽  
...  
Keyword(s):  
Extracorporeal Membrane Oxygenation ◽  
Lung Transplantation ◽  
Postoperative Period ◽  
Compartment Model ◽  
Volume Of Distribution ◽  
Self Control ◽  
Control Group ◽  
Membrane Oxygenation ◽  
Population Pk ◽  
Before And After

ABSTRACT Little is known about the influence of extracorporeal membrane oxygenation (ECMO) on the pharmacokinetics (PK) of caspofungin. The aim of this study was to describe population PK of caspofungin in patients with and without ECMO during the postoperative period of lung transplantation (LTx) and to investigate covariates influencing caspofungin PK. We compared ECMO patients with non-ECMO patients, and patients before and after ECMO weaning as self-controls, to analyzed changes in caspofungin PK. Eight serial blood samples were collected from each patient for PK analysis. The population PK of caspofungin was described using nonlinear mixed-effects modeling. Twelve ECMO and 7 non-ECMO lung transplant recipients were enrolled in this study. None of the patients received renal replacement therapy during any part of the study period. The PK of caspofungin was best described by a two-compartment model. There were no significant differences in the PK parameters and concentrations of caspofungin among the ECMO, non-ECMO, and self-control group. In the final covariate model, we found that there was a significant association between the male gender and increased distribution volume, that a higher sequential organ failure assessment score was related to an increase in intercompartmental clearance, and that a longer operative time was related to an increase in clearance and the volume of distribution. ECMO did not have a significant impact on the PK of caspofungin in patients after LTx. Some factors were identified as statistically significant covariates related to the PK of caspofungin; however, their impact on clinical practice of caspofungin needs to be investigated further in more studies. (This study has been registered at ClinicalTrials.gov under identifier NCT03766282.)

Population pharmacokinetic (PK) analysis of ABT-869 in solid tumors and acute myelogenous leukemia (AML) patients

2009 ◽  
Vol 27 (15_suppl) ◽  
pp. 3567-3567
Author(s):  
N. Gupta ◽  
P. M. Diderichsen ◽  
J. Steinberg ◽  
J. L. Ricker ◽  
R. Humerickhouse ◽  
...  
Keyword(s):  
Body Weight ◽  
Growth Factor ◽  
Solid Tumors ◽  
Plasma Concentrations ◽  
Compartment Model ◽  
Disease State ◽  
Myelogenous Leukemia ◽  
Population Pharmacokinetic ◽  
First Order ◽  
Population Pk

3567 Background: ABT-869 is an orally bioavailable, potent and specific inhibitor of all vascular endothelial growth factor and platelet derived growth factor family receptor tyrosine kinases. The objectives of this analysis were to understand the population pharmacokinetics of ABT-869 and explore the effect of several demographic/disease state covariates influencing ABT-869 disposition. Methods: A population PK analysis of 181 patients (pts) enrolled in two phase 1 (multiple types of solid tumors and AML) and three phase 2 monotherapy studies (non-small cell lung cancer, hepatocellular carcinoma [HCC] and renal cell carcinoma) was conducted. Approximately 90% of pts received ABT-869 based on body-weight dosing while the remaining pts had flat dosing. Available plasma concentrations obtained after intensive and sparse pre-dose PK sampling were analyzed by population PK using the non linear mixed effects modeling (NONMEM) approach. Potential covariates including body weight, body surface area (BSA), age, sex, creatinine clearance (CrCL) and disease state (HCC vs. non-HCC pts) were tested. Results: The mean body weight of enrolled pts was 71 kg and 57% were Asian, 36% Caucasian and 7% other races. The ABT-869 plasma concentration time profile was well described by a one-compartment model with first order absorption and elimination process. Oral clearance (CL/F) was not affected by body weight (range 35–177 kg); however, apparent volume of distribution (V/F) increased by 6L per 0.1 mg/m2 increase in BSA. CrCL (39.9–290.3 ml/min) was not a significant covariate on V/F and CL/F suggesting renally impaired pts do not require a different dose/dosing regimen. HCC pts had ∼40% lower CL/F values than pts with other malignancies suggesting a lower dose would be appropriate for HCC (Child Pugh A and B) pts. Conclusions: Population PK analysis showed that ABT-869 PK can be well described by a one-compartment model with first order absorption and elimination. Race and impaired renal function does not appear to alter PK. HCC pts had lower CL/F value therefore a lower dose may be recommended in these patients. Implications of increased V/F with increasing body size and appropriate dosing strategy are undergoing further analysis. [Table: see text]

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