A common approach to assess the efficacy of piperacillin is to first measure the total concentration and afterwards apply a theoretical unbound fraction of 70% to obtain the unbound concentration. However, hypoalbuminemia is a common phenomenon in critically ill patients, resulting in variations in unbound fraction, therefore we aimed to simulate the impact of piperacillin unbound fraction fluctuations on the predictive performance of a population pharmacokinetic model and on the dosing recommendations of piperacillin. Unbound factors of 70%, 75%, 80% and 85% were applied to total concentrations of piperacillin administered by continuous infusion from an external dataset. A validated model was used for assessment of predictive performance and to estimate patient clearance. Dosing simulations were performed to evaluate target attainment. Variation in unbound fractions caused minimal impact on piperacillin clearance and target attainment but seemed to influence model validity.
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http://dx.doi.org/10.1111/bcp.15619 | DOI Listing |
Front Physiol
January 2025
Human Physiology Research Unit, Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, ON, Canada.
Introduction: The fraction of drug circulating in the blood that is not bound to plasma proteins ( ) is considered pharmacologically active since it readily binds to its receptor. evidence suggests that changes in temperature and pH affect the affinity of drug binding to plasma proteins, resulting in changes in . In light of the well-established effects of exercise on body temperature and blood pH, we investigated whether an increase in blood temperature and decrease in pH facilitated through passive heating and exercise translated to a change in the of caffeine.
View Article and Find Full Text PDFWe review the case of a 58-year-old female on extracorporeal membrane oxygenation (ECMO) support diagnosed with invasive pulmonary aspergillosis (IPA). Intravenous isavuconazole was started, requiring dose escalation to achieve isavuconazole trough concentration (ISA-Cmin) within the therapeutic range (2.5-5.
View Article and Find Full Text PDFJ Pharm Biomed Anal
January 2025
Ryvu Therapeutics, Sternbacha 2, Cracow 30-394, Poland.
Accurate determination of plasma protein binding (PPB) is crucial in understanding the pharmacokinetics and pharmacodynamics of drugs, particularly for highly bound compounds where traditional methods may fall short. In this study, we present a pioneering approach for the precise determination of PPB that takes advantage of the lipophilicity of highly bound compounds. Twenty four highly bound compounds (with a fraction unbound (f) from 10 to 10) were tested with the most commonly used method, i.
View Article and Find Full Text PDFTher Drug Monit
February 2025
School of Pharmacy, University of Queensland, Brisbane, QLD, Australia.
Background: Therapeutic monitoring is routinely performed to ensure tacrolimus whole-blood concentrations fall within a predefined target. Despite this, patients still experience inefficacy and toxicity that could be related to variability in free (unbound) tacrolimus exposure. Therefore, the aim of this study was to compare tacrolimus-free plasma (C u ), total plasma (C p ), and whole-blood (C wb ) concentrations in adult kidney transplant recipients and to characterize tacrolimus disposition across different matrices.
View Article and Find Full Text PDFPharmaceutics
December 2024
Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China.
SPT-07A, a D-borneol, is currently being developed in China for the treatment of ischemic stroke. We aimed to create a whole-body physiologically-based pharmacokinetic (PBPK) model to predict the pharmacokinetics of SPT-07A in rats, dogs, and humans. The in vitro metabolism of SPT-07A was studied using hepatic, renal, and intestinal microsomes.
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