What is PBPK Modeling?

August 25, 2020

Key Takeaways

  • PBPK modeling is a method used to predict the impacts of chemicals based on where it will be distributed and how it is metabolized in the body.
  • These particular PK models are based on mathematical equations with the consideration of the physiological processes and tissue-specific characteristics.
  • One of the most notable applications of PBPK modeling is to support decision-making in drug development, chemical risk assessment, and occupational exposure assessment.

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Principles And Techniques Of A PBPK Model

PBPK models are based on mathematical equations that take into account factors such as chemical properties, physiological processes, and tissue-specific characteristics. 

These models are used to simulate the behavior of a drug in the body, including how it is absorbed, distributed, metabolized, and eliminated. The model is then used to predict the drug’s pharmacokinetic parameters, such as its absorption rate, bioavailability, and half-life.

The principles and techniques of a PBPK model are based on the principles of pharmacokinetics and physiology. A PBPK model typically consists of a set of equations that describe the transport of a drug through the body. These equations take into account factors such as chemical properties, physiological processes, and tissue-specific characteristics.

The equations used in a PBPK model can be divided into two categories: compartmental and non-compartmental. 

  • Compartmental equations are used to describe the distribution of a drug within the body.
  • Non-compartmental equations are used to describe the absorption and elimination of a drug.

In addition to the equations, the model also requires data on the drug’s pharmacokinetic parameters, such as its absorption rate, bioavailability, and half-life. This data can be obtained through in-vitro and in-vivo studies, or from published literature.

The model is then used to simulate the behavior of the drug in the body. This includes how it is absorbed, distributed, metabolized, and eliminated. The results of the model can then be used to predict the pharmacokinetic parameters and to support decision-making in areas such as drug development, chemical risk assessment, and occupational exposure assessment.

ScitoVation PBPK Modeling


The traditional and most common use for PBPK models in risk assessment is to understand how the compound is absorbed, distributed, metabolized and excreted (ADME). Beyond ADME, ScitoVation uses PBPK models to assist clients with:


  • In vitro to in vivo extrapolation (IVIVE) or interspecies extrapolation
  • Intra-species extrapolation (see our Case Study for more)
  • Route-to-route extrapolation 
  • High-to-low dose extrapolation
  • Population variability assessment
  • Human biomonitoring data and epidemiological data 

PBPK Model Methodology & Components

PBPK Model Methodology & Components is a section of the PBPK modeling process that is used to accurately predict the fate of drugs in the body. The methodology involves the use of mathematical equations to take into account factors such as chemical properties, physiological processes, and tissue-specific characteristics. The components of a PBPK model include the following:

• Compartmentalization: This is the process of dividing the body into different compartments, such as organs, tissues, and cells, and assigning each compartment a rate of drug absorption, distribution, and elimination.

• Kinetics: This is the study of the rate at which drugs move through the body. This includes the absorption, distribution, metabolism, and excretion of drugs.

• Physiological Parameters: These are parameters that are used to describe the body’s physiological processes, such as blood flow, tissue permeability, and organ function.

• Pharmacokinetic Parameters: These are parameters that are used to describe the pharmacokinetics of a drug, such as the absorption, distribution, metabolism, and excretion of the drug.

• Biopharmaceutics: This is the study of how the physical and chemical properties of a drug affect its absorption, distribution, metabolism, and excretion.

• Clinical Data: This is the data that is collected during clinical trials and is used to validate the PBPK model.

• Model Validation: This is the process of validating the PBPK model by comparing the predicted results to the observed clinical data.

Benefits And Applications Of Using PBPK Models

PBPK modeling is a powerful tool for drug development and has a wide range of applications. It can be used to predict the pharmacokinetic properties of a drug, such as absorption, distribution, metabolism, and excretion. 

This allows researchers to better understand the behavior of a drug in the body and optimize its dosing and safety. Additionally, PBPK modeling can be used to assess the potential for drug-drug interactions and to evaluate the effects of genetic variants on drug response.

PBPK modeling allows for the evaluation of drug exposure in different tissues and organs. This is especially important for drugs that have a high degree of tissue specificities, such as those that are used to treat cancer or autoimmune diseases. PBPK models can also be used to assess the potential for drug accumulation in the body over time and to predict the long-term effects of drugs on the body.

PBPK models can also be used to evaluate the potential for drug-drug interactions, as well as the effects of genetic variants on drug response. This is important for personalized medicine, as it allows researchers to predict how a drug will interact with a patient’s individual genetic makeup.

Finally, PBPK models can be used to assess the potential for drug-environment interactions, such as how a drug might interact with pollutants in the environment. This is especially important for drugs that are used to treat chronic diseases, as it can help researchers understand how environmental factors may affect drug efficacy.

FAQs

What is PBPK model for drug interaction?

PBPK modeling is a type of pharmacokinetic (PK) modeling used to predict the distribution and metabolism of drugs in the body. It takes into account factors such as chemical properties, physiological processes, and tissue-specific characteristics to predict drug-drug interactions whether it will result in an increased or decreased effect of one or both drugs. 

How is PBPK modeling used in drug development?

PBPK modeling is used to support decision-making in drug development, helping to determine the ideal dose, route of administration, and formulation of a drug. It can also be used to predict drug-drug interactions, assess the risk of adverse reactions, and evaluate the efficacy of new drugs.

Which software is used in PBPK modeling?

There are several software programs available that are specifically designed for PBPK modeling. These include PK-Sim®, GastroPlus®, Simcyp®, and Phoenix®.

What is PK profiling?

PK profiling is the process of obtaining a detailed description of the pharmacokinetic properties of a drug in a population. This is typically done by collecting data from clinical trials and using it to develop a PK profile, which is then utilized in decision-making during drug development. t. 

What model is used for drug designing?

PBPK modeling is often used in drug design, as it can provide insight into how a drug will interact with the body.