A toxicokinetic model for fish including multiphase sorption features.

Area of Science:

• Physiologically Based Toxicokinetic (PBTK) Modeling
• Environmental Toxicology
• Pharmacokinetics

Background:

• Existing PBTK models vary in complexity, often relying on lumped parameters fitted to experimental data.
• Fitted parameters limit model applicability and hinder a fundamental understanding of chemical processes.
• A need exists for PBTK models based solely on intrinsic physiological and physicochemical properties.

Purpose of the Study:

• To develop a PBTK model independent of fitted parameters, utilizing only well-defined physiological and physicochemical inputs.
• To enhance the understanding of chemical uptake, distribution, and elimination processes within organisms.
• To lay the groundwork for future model extensions, including ionic compounds and active transport.

Main Methods:

• Development of a novel PBTK model framework.
• Integration of fundamental physiological and physicochemical parameters.
• Model validation using experimental data for nonpolar chemicals.

Main Results:

• The developed PBTK model successfully predicted chemical uptake, clearance, and bioaccumulation for nonpolar compounds.
• The model demonstrates the feasibility of a parameter-free approach in PBTK modeling.
• Achieved accurate predictions without relying on fitted lumped parameters.

Conclusions:

• A PBTK model based entirely on physiological and physicochemical parameters can accurately predict chemical behavior.
• This approach offers a more robust and broadly applicable alternative to models requiring fitted parameters.
• The study advances PBTK modeling by enabling a deeper mechanistic understanding and future extensions.