Windows based general PBPK/PD modeling software

Area of Science:

• Pharmacokinetics and Pharmacodynamics
• Computational Biology
• Developmental Toxicology

Background:

• Physiologically based pharmacokinetic (PBPK) models are crucial for understanding drug disposition.
• Accurate modeling of postnatal growth is essential for pediatric and developmental risk assessments.
• Existing models often lack comprehensive integration of growth and physiological changes from birth through adulthood.

Purpose of the Study:

• To develop and validate a PBPK model, PostNatal, specifically designed for postnatal growth.
• To integrate organ/tissue growth curves and blood flow dynamics in humans and animal models.
• To enable simulation of pharmacokinetic and pharmacodynamic (PD) effects during postnatal development.

Main Methods:

• Development of algorithms for organ/tissue growth curves (birth to adulthood) in humans, dogs, rats, and mice.
• Implementation of four linked PBPK models within a Windows-based program.
• Integration of metabolic processes using first-order or Michaelis-Menten kinetics.
• Utilized weighted least square regression for data fitting.
• Incorporated linkages for pharmacodynamic (PD) effect simulations.

Main Results:

• The PostNatal program successfully models postnatal growth trajectories.
• Calculations of organ/tissue weight and blood flow are dynamically adjusted based on species-specific growth curves.
• The integrated PBPK models allow for flexible simulation of independent or coupled physiological processes.
• The model demonstrates capability for simulating pharmacodynamic (PD) outcomes.

Conclusions:

• The PostNatal PBPK model provides a robust framework for studying drug disposition during postnatal development.
• This tool facilitates species-specific risk assessments and informs therapeutic strategies in pediatric populations.
• The integrated approach enhances the predictive power of PBPK modeling for developmental pharmacokinetics and pharmacodynamics.