US EPA

EPA has developed a physiological information database (created using Microsoft ACCESS) intended to be used in PBPK modeling. The database contains physiological parameter values for humans from early childhood through senescence as well as similar data for laboratory animal species (primarily rodents). The database information was collected through extensive literature search. To date, all of the data entries have been verified by an independent contractor as a means of quality assurance and quality control (QA/QC).

The PID is available for download as a compressed Microsoft ACCESS file. To open the compressed file, first save the file on your hard drive, and unzip the contents into a folder of your choosing. EPA is planning to also make this available via the HERO database in FY 2010.

Physiologically-based pharmacokinetic (PBPK) models have increasingly been employed in chemical health risk assessments carried out by the U.S. Environmental Protection Agency (EPA), and it is anticipated that their use will continue to increase. Because relevant physiological parameter values (e.g. alveolar ventilation, blood flow and tissue volumes, glomerular filtration rate) are critical components of these models but are scattered among various sources in the scientific literature, EPA has sponsored several efforts to compile these data into an electronic relational database that is intended to be suitable for use by researchers and risk assessors.

As an important class of dosimetry models, PBPK models are useful for predicting internal dose at target organs for risk assessment applications. Dose-response relationships that appear unclear or confusing at the administered dose level can become more understandable when expressed on the basis of internal dose of the chemical. To predict internal dose level, PBPK models use physiological data to construct mathematical representations of biological processes associated with the absorption, distribution, metabolism, and elimination of compounds. With the appropriate data, these models can be used to extrapolate across species, lifestages, and exposure scenarios, as well as address various sources of uncertainty in risk assessments. This database contains a collection of physiological data relevant for parameterizing PBPK models for children, adults, and the elderly. In addition, the database contains physiological data for parameterizing PBPK models for young (i.e., developing) and adult rodents.

EPA is releasing a database containing values of human and animal physiological parameters for public comment. The information assembled in this database should provide a scientific basis for selection of several key physiological parameters for dosimetry modeling for application in risk assessment.

This is the Final Release. EPA also expects to make this database available via HERO.

Because the database may be updated at future intervals, modelers and others who have data that would augment the existing information or who may have other suggestions to improve the database are encouraged to email the contact listed above.
Some specific questions are:

• Do you find the physiological data for humans and test animals in the database useful, relevant, and accurate?
• Do you know of any other data that would be valuable addtion to the database ? If so, please provide references or link to the information.
• Do you know of other related publicly available information resources that EPA should be aware of, either for inclusion into the database or as a collaboration to further extend the usefulness of the database.

If you have used the database in your work, would like to share your experience, please forward comments to Rob Dewoskin or Bob Sonawane.

Additional Contact Information

For communications and outreach
Linda Tuxen
by phone at: 703–347–8609
by e-mail at : tuxen.linda@epa.gov

For technical and scientific questions
Robert Dewoskin
by phone at: 919-541-1089
by email at: dewoskin.rob@epa.gov