scholarly journals Pharmacodynamic modeling of chemotherapeutic effects: Application of a transit compartment model to characterize methotrexate effects in vitro

AAPS PharmSci ◽  
2002 ◽  
Vol 4 (4) ◽  
pp. 212-222 ◽  
Author(s):  
Evelyn D. Lobo ◽  
Joseph P. Balthasar
Keyword(s):  
Compartment Model ◽  
Pharmacodynamic Modeling ◽  
Transit Compartment ◽  
Transit Compartment Model

scholarly journals Pharmacodynamic Modeling of Clarithromycin against Macrolide-Resistant [PCR-Positive mef(A) or erm(B)] Streptococcus pneumoniae Simulating Clinically Achievable Serum and Epithelial Lining Fluid Free-Drug Concentrations

2002 ◽  
Vol 46 (12) ◽  
pp. 4029-4034 ◽  
Author(s):  
Ayman M. Noreddin ◽  
Danielle Roberts ◽  
Kim Nichol ◽  
Aleksandra Wierzbowski ◽  
Daryl J. Hoban ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Compartment Model ◽  
Free Drug ◽  
Pharmacodynamic Modeling ◽  
Epithelial Lining ◽  
Bacterial Killing ◽  
Epithelial Lining Fluid ◽  
Initial Inoculum ◽  
Drug Concentrations

ABSTRACT The association between macrolide resistance mechanisms and clinical outcomes remains understudied. The present study, using an in vitro pharmacodynamic model, assessed clarithromycin (CLR) activity against mef(A)-positive and erm(B)-negative Streptococcus pneumoniae isolates by simulating free-drug concentrations in serum and both total (protein-bound and free) and free drug in epithelial lining fluid (ELF). Five mef(A)-positive and erm(B)-negative strains, one mef(A)-negative and erm(B)-positive strain, and a control [mef(A)-negative and erm(B)-negative] strain of S. pneumoniae were tested. CLR was modeled using a one-compartment model, simulating a dosage of 500 mg, per os, twice a day (in serum, free-drug Cp maximum of 2 μg/ml, t 1/2 of 6 h; in ELF, C ELF(total) maximum of 35μg/ml, t 1/2 of 6 h; CELF(free) maximum of 14 μg/ml, t 1/2 of 6 h). Starting inocula were 106 CFU/ml in Mueller-Hinton broth with 2% lysed horse blood. With sampling at 0, 4, 8, 12, 20, and 24 h, the extent of bacterial killing was assessed. Achieving CLR T/MIC values of ≥90% (AUC0-24/MIC ratio, ≥61) resulted in bacterial eradication, while T>MIC values of 40 to 56% (AUC0-24/MIC ratios of ≥30.5 to 38) resulted in a 1.2 to 2.0 log10 CFU/ml decrease at 24 h compared to that for the initial inoculum. CLR T/MIC values of ≤8% (AUC0-24/MIC ratio, ≤17.3) resulted in a static effect or bacterial regrowth. The high drug concentrations in ELF that were obtained clinically with CLR may explain the lack of clinical failures with mef(A)-producing S. pneumoniae strains, with MICs up to 8 μg/ml. However, mef(A) isolates for which MICs are ≥16 μg/ml along with erm(B) may result in bacteriological failures.

A Transit Compartment Model Unmasks OxyContin's Reflective Pharmacokinetics From Urine Measurements in Humans

2014 ◽  
Vol 28 (2) ◽  
pp. 96-108
Author(s):  
Oscar A. Linares ◽  
William E. Schiesser ◽  
Annemarie Daly Linares ◽  
Darko Stefanovski ◽  
Raymond C. Boston
Keyword(s):  
Compartment Model ◽  
Transit Compartment ◽  
Transit Compartment Model

scholarly journals Comparison of oral absorption models for pregabalin: usefulness of transit compartment model

2016 ◽  
Vol Volume 10 ◽  
pp. 3995-4003 ◽  
Author(s):  
Taegon Hong ◽  
Seunghoon Han ◽  
Jongtae Lee ◽  
Sangil Jeon ◽  
Dong-Seok Yim
Keyword(s):  
Oral Absorption ◽  
Compartment Model ◽  
Transit Compartment ◽  
Absorption Models ◽  
Transit Compartment Model

Simultaneous Characterization of Intravenous and Oral Pharmacokinetics of Lychnopholide in Rats by Transit Compartment Model

Planta Medica ◽  
2015 ◽  
Vol 81 (12/13) ◽  
pp. 1121-1127 ◽  
Author(s):  
Larissa Lachi-Silva ◽  
Sherwin Sy ◽  
Alexander Voelkner ◽  
João de Sousa ◽  
João Lopes ◽  
...  
Keyword(s):  
Compartment Model ◽  
Transit Compartment ◽  
Oral Pharmacokinetics ◽  
Transit Compartment Model

scholarly journals Fluoxetine pharmacokinetics and tissue distribution suggest a possible role in reducing SARS-CoV-2 titers

F1000Research ◽  
2021 ◽  
Vol 10 ◽  
pp. 477
Author(s):  
Andy R. Eugene
Keyword(s):  
Tissue Distribution ◽  
Day Treatment ◽  
Compartment Model ◽  
Population Pharmacokinetic ◽  
Parameter Estimates ◽  
Pharmacokinetic Data ◽  
Human Lung Cells ◽  
Retrospective Clinical Study ◽  
Target Plasma Concentration

Background.  Recent in vitro studies have shown fluoxetine inhibits the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pathogen, including variants B.1.1.7 and B.1.351, SARS-CoV-2 spike mutations (E484K, K417N, N501Y), and one retrospective clinical study reported fluoxetine exposure at a median dose of 20 mg in patients with the SARS-CoV-2 coronavirus disease 2019 (COVID-19) had a significantly lower risk of intubation and death. The aim of this study is to conduct in silico population pharmacokinetic dosing simulations to quantify the percentage of patients achieving a trough level for the effective concentration resulting in 90% inhibition (EC90) of SARS-CoV-2 as reported in Calu-3 human lung cells.  Methods.  Population pharmacokinetic parameter estimates for a structural one-compartment model with first-order absorption were used to simulate fluoxetine pharmacokinetic data. A population of 1,000 individuals were simulated at standard fluoxetine doses (20 mg/day, 40 mg/day, and 60 mg/day) to estimate the percentage of the patients achieving a trough plasma level for the EC90 SARS-CoV-2 inhibitory concentration for a 10 day treatment period. All analyses were conducted via statistical programming in R.  Results.  Standard fluoxetine antidepressant doses resulted in a range of 81% to 97% of the patient population achieving a trough target plasma concentration of 23.2 ng/ml at day 10 and translates to a lung-tissue distribution coefficient of 60-times higher (EC90 of 4.02 mM). At a dose of 40 mg per day, at least 87% of patients will reach the trough target EC90 concentration within three days.   Conclusion. Overall, the findings of this population pharmacokinetic dosing study corroborates in vitro and observational clinical studies reporting the first selective serotonin reuptake inhibitor fluoxetine inhibits the SARS-CoV-2 pathogen at commonly treated doses in the practice of psychiatry.

scholarly journals 273 Application of pharmacokinetic-pharmacodynamic modeling to select the optimal dose of ALX148, a CD47 blocker

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A296-A296
Author(s):  
Oleg Demin ◽  
Elena Vasileva
Keyword(s):  
Bone Marrow ◽  
Lymph Nodes ◽  
Clinical Data ◽  
Optimal Dose ◽  
Confidence Bands ◽  
Pharmacodynamic Modeling ◽  
Tumor Tissues ◽  
Vitro Data ◽  
In Vitro Data

BackgroundALX148 is a fusion protein comprised of a high-affinity CD47 blocker linked to an inactive immunoglobulin Fc region. Optimal doses selection is increasingly important in clinical setup and can be guided by an assessment of target receptor occupancy (RO) and pharmacodynamics (PD) effect in the site of action. However, direct measurement of RO and PD effect in the tumor tissue is challenging. A mechanistic pharmacokinetic (PK)-PD model was developed to predict CD47 occupancy and PD effect in tumor tissues for ALX148.MethodsThe developed semi-mechanistic PK/RO/PD model describes the PK of ALX148 and its distribution to non-Hodgkin lymphoma tumor tissues (lymph nodes, spleen, and bone marrow). The model includes non-linear clearance of ALX148 due to target CD47 receptor binding and further internalization of the complex. CD47 RO was described on red blood cells and tumor cells taking into account the number of cells and CD47 expression (molecules per cell). Parameters were fitted against clinical PK and in vitro data. In vitro data on stimulation of phagocytosis by ALX148 in the presence of antibodies inducing antibody-dependent cellular phagocytosis (ADCP) was used to estimate the RO-PD relationship. Clinical data on RO in the periphery was used for model validation.ResultsThe model successfully described dose-dependence ALX148 clinical PK and RO data. Predicted trough median CD47 occupancy in the spleen, lymph nodes, and bone marrow during the treatment with 10 mg/kg QW ALX148 was 98% (95% confidence bands: 95%–99%), whereas 30 mg/kg Q2W resulted in 99% CD47 occupancy (95% confidence bands: 98%–99%). ADCP of cancer cells was predicted to be increased by ~1.8 times during the treatment with both regimens of ALX148: 10 mg/kg QW and 30 mg/kg Q2W. Dose 3 mg/kg resulted in the lower induction of ADCP than 10 mg/kg: 1.6 vs 1.8 (p-value < 0.001).ConclusionsThe model was successfully calibrated and validated against both in vitro and clinical data on ALX148. It was predicted that 10 mg/kg QW is an optimal dose of ALX148 to occupy more than 90% of CD47 in the tumor tissues to achieve maximal induction of phagocytosis caused by ADCP stimulating antibodies such as rituximab. This approach can be applied for the optimal dose selection of other anti-CD47 agents taking into account their specific features as binding properties, size, etc.

scholarly journals Semimechanistic Pharmacokinetic/Pharmacodynamic Modeling of Fosfomycin and Sulbactam Combination against Carbapenem-Resistant Acinetobacter baumannii

2021 ◽  
Vol 65 (5) ◽  
Author(s):  
Sazlyna Mohd Sazlly Lim ◽  
Aaron J. Heffernan ◽  
Jason A. Roberts ◽  
Fekade B. Sime
Keyword(s):  
Acinetobacter Baumannii ◽  
Treatment Options ◽  
Pharmacodynamic Modeling ◽  
Synergistic Activity ◽  
Bacterial Burden ◽  
Target Attainment ◽  
Content Type ◽  
Carbapenem Resistant ◽  
Time Kill

ABSTRACT Due to limited treatment options for carbapenem-resistant Acinetobacter baumannii (CR-AB) infections, antibiotic combinations are now considered potential treatments for CR-AB. This study aimed to explore the utility of fosfomycin-sulbactam combination (FOS/SUL) therapy against CR-AB isolates. Synergism of FOS/SUL against 50 clinical CR-AB isolates was screened using the checkerboard method. Thereafter, time-kill studies against two CR-AB isolates were performed. The time-kill data were described using a semimechanistic pharmacokinetic/pharmacodynamic (PK/PD) model. Monte Carlo simulations were then performed to estimate the probability of stasis, 1-log kill, and 2-log kill after 24 h of combination therapy. The FOS/SUL combination demonstrated a synergistic effect against 74% of isolates. No antagonism was observed. The MIC50 and MIC90 of FOS/SUL were decreased 4- to 8-fold, compared to the monotherapy MIC50 and MIC90. In the time-kill studies, the combination displayed bactericidal activity against both isolates and synergistic activity against one isolate at the highest clinically achievable concentrations. Our PK/PD model was able to describe the interaction between fosfomycin and sulbactam in vitro. Bacterial kill was mainly driven by sulbactam, with fosfomycin augmentation. FOS/SUL regimens that included sulbactam at 4 g every 8 h demonstrated a probability of target attainment of 1-log10 kill at 24 h of ∼69 to 76%, compared to ∼15 to 30% with monotherapy regimens at the highest doses. The reduction in the MIC values and the achievement of a moderate PTA of a 2-log10 reduction in bacterial burden demonstrated that FOS/SUL may potentially be effective against some CR-AB infections.

Maxacalcitol Pharmacokinetic–Pharmacodynamic Modeling and Simulation for Secondary Hyperparathyroidism in Patients Receiving Maintenance Hemodialysis

Drug Research ◽  
2021 ◽  
Author(s):  
Mizuki Fukazawa-Shinotsuka ◽  
Tomohisa Saito ◽  
Masaichi Abe ◽  
Satofumi Iida ◽  
I-Ting Wang ◽  
...  
Keyword(s):  
Clinical Study ◽  
Modeling And Simulation ◽  
Secondary Hyperparathyroidism ◽  
Compartment Model ◽  
Japanese Patients ◽  
Pharmacodynamic Modeling ◽  
Maintenance Hemodialysis ◽  
Population Pharmacokinetic ◽  
Limit Of Quantification ◽  
Clinical Pharmacology Study

Abstract Background Maxacalcitol was approved in Taiwan in 2018 as the first active vitamin D3 injection for secondary hyperparathyroidism (SHPT) in patients on maintenance hemodialysis. However, no data from any clinical study with maxacalcitol in Taiwanese patients is available. Objectives This analysis aimed to evaluate the profiles of parathyroid hormone (PTH) and calcium (Ca) concentrations in Taiwanese SHPT patients on hemodialysis and maxacalcitol. Methods We developed population pharmacokinetic (PK) and pharmacodynamic (PD) models using a modeling and simulation approach. The data for these analyses were obtained from two studies: a clinical pharmacology study in Japanese patients and an ethnic comparison study in healthy Japanese and -Taiwanese volunteers. We then conducted a simulation study with a PK-PD model comprising the PK and PD models developed here. Results Serum maxacalcitol concentration profile was modeled using a two-compartment model that took into consideration the distribution of concentrations below the lower limit of quantification. An ethnic difference in clearance was included in the PK model as a covariate. A PD model that used a PTH/Ca feedback loop best described the observed data. There were no significant differences in Ca or PTH concentrations between Taiwanese and Japanese based on the simulation results from our PK-PD model, even though maxacalcitol exposure was approximately 40% higher in Taiwanese than in Japanese. Conclusions On the basis of these population PK and PD analyses and the clinical study conducted in Japan, there is no clinically relevant difference between Taiwanese and Japanese in terms of serum Ca or PTH levels.

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