[Federal Register Volume 74, Number 72 (Thursday, April 16, 2009)]
[Pages 17666-17667]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E9-8795]



[FRL-8785-9; Docket ID No. EPA-HQ-ORD-2009-0173]

Physiological Parameters Database for PBPK Modeling

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of public comment period.


SUMMARY: EPA is announcing a public comment period for an on-line 
database file, using the Microsoft[supreg] Access database management 
system, that contains a comprehensive collection of physiological 
parameter data intended to be suitable for application in 
physiologically based pharmacokinetic (PBPK) modeling. The public 
comment period will be for 30 days. EPA requests that interested users 
comment on the functionality or usability of this resource and provide 
comments that may be considered for improving the final product.
    The draft database represents a compilation of several individual 
databases developed over the past few years. It contains physiological 
parameter data for humans from infancy through old age, as well as data 
for experimental laboratory species. EPA requests that end-users 
provide feedback regarding their experience working with this database. 
Users are also encouraged to comment on specific studies or methods 
employed in the

[[Page 17667]]

studies included in the entire draft database.
    As a means of quality assurance and quality control (QA/QC), about 
30% of the data entries, randomly selected, have been verified by an 
independent contractor. This QA/QC process will be ongoing.

DATES: The 30-day public comment period begins April 16, 2009 and ends 
May 18, 2009. Technical comments should be in writing and must be 
received by EPA by close of business, May 18, 2009.

ADDRESSES: The draft database is available for download from the U.S. 
EPA Web site http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=204443. Users must have Microsoft[supreg] Access 
in order to open and manipulate the database file.
    Comments may be submitted electronically via EPA's E-Docket, by 
mail, by facsimile, or by hand delivery/courier. Please follow the 
detailed instructions as provided in the SUPPLEMENTARY INFORMATION 
section of this notice.

FOR FURTHER INFORMATION CONTACT: For information on the public comment 
period, contact the Office of Environmental Information Docket; 
telephone: 202-566-1752; facsimile: 202-566-1753; or e-mail: 
[email protected].
    If you have questions about the database, please contact the 
Information Management Staff, National Center for Environmental 
Assessment, U.S. Environmental Protection Agency, Washington, DC 20460; 
telephone: 703-347-8561; facsimile: 703-347-8691; or e-mail: 
[email protected].


I. Information About the Product

    Physiologically based pharmacokinetic (PBPK) models represent an 
important class of dosimetry models that 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.

II. How To Submit Technical Comments to the Docket at Regulations.gov

    Submit your comments, identified by Docket ID No. EPA-HQ-ORD-2009-
0173, by one of the following methods:
     http://www.regulations.gov: Follow the on-line 
instructions for submitting comments.
     E-mail: [email protected].
     Fax: 202-566-1753.
     Mail: Office of Environmental Information (OEI) Docket 
(Mail Code: 2822T), U.S. Environmental Protection Agency, 1200 
Pennsylvania Ave., NW., Washington, DC 20460. The phone number is 202-
     Hand Delivery: The OEI Docket is located in the EPA 
Headquarters Docket Center, Room 3334 EPA West Building, 1301 
Constitution Ave., NW., Washington, DC. The EPA Docket Center Public 
Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through 
Friday, excluding legal holidays. The telephone number for the Public 
Reading Room is 202-566-1744. Such deliveries are only accepted during 
the docket's normal hours of operation, and special arrangements should 
be made for deliveries of boxed information.
    If you provide comments by mail or hand delivery, please submit an 
original and three copies of the comments. For attachments, provide an 
index, number pages consecutively with the comments, and submit an 
unbound original and three copies.
    Instructions: Direct your comments to Docket ID No. EPA-HQ-ORD-
2009-0173. Please ensure that your comments are submitted within the 
specified comment period. Comments received after the closing date will 
be marked ``late,'' and may only be considered if time permits. It is 
EPA's policy to include all comments it receives in the public docket 
without change and to make the comments available online at http://www.regulations.gov, including any personal information provided, 
unless a comment includes information claimed to be Confidential 
Business Information (CBI) or other information whose disclosure is 
restricted by statute. Do not submit information that you consider to 
be CBI or otherwise protected through http://www.regulations.gov or e-
mail. The http://www.regulations.gov Web site is an ``anonymous 
access'' system, which means EPA will not know your identity or contact 
information unless you provide it in the body of your comment. If you 
send an e-mail comment directly to EPA without going through http://www.regulations.gov, your e-mail address will be automatically captured 
and included as part of the comment that is placed in the public docket 
and made available on the Internet. If you submit an electronic 
comment, EPA recommends that you include your name and other contact 
information in the body of your comment and with any disk or CD-ROM you 
submit. If EPA cannot read your comment due to technical difficulties 
and cannot contact you for clarification, EPA may not be able to 
consider your comment. Electronic files should avoid the use of special 
characters, any form of encryption, and be free of any defects or 
viruses. For additional information about EPA's public docket visit the 
EPA Docket Center homepage at http://www.epa.gov/epahome/dockets.htm.
    Docket: Documents in the docket are listed in the http://www.regulations.gov index. Although listed in the index, some 
information is not publicly available, e.g., CBI or other information 
whose disclosure is restricted by statute. Certain other materials, 
such as copyrighted material, are publicly available only in hard copy. 
Publicly available docket materials are available either electronically 
in http://www.regulations.gov or in hard copy at the OEI Docket in the 
EPA Headquarters Docket Center.

    Dated: March 16, 2009.
Rebecca Clark,
Acting Director, National Center for Environmental Assessment.
[FR Doc. E9-8795 Filed 4-15-09; 8:45 am]