[Federal Register Volume 70, Number 161 (Monday, August 22, 2005)]
[Notices]
[Pages 48950-48952]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-16597]


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ENVIRONMENTAL PROTECTION AGENCY

[FRL-7957-2; E-Docket ID No. ORD-2005-0022]


Approaches for the Application of Physiologically-Based 
Pharmacokinetic (PBPK) Models and Supporting Data in Risk Assessment

AGENCY: Environmental Protection Agency.

ACTION: Notice of extension of public comment period.

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SUMMARY: The U.S. Environmental Protection Agency (EPA) is extending 
the public comment period on the external review draft document titled, 
``Approaches for the Application of Physiologically-Based 
Pharmacokinetic (PBPK) Models and Supporting Data in Risk Assessment'' 
(EPA/600/R-05/043A), by 45 days. On July 28, 2005, EPA published a 
Federal Register notice (70 FR 43692) announcing: (1) The public 
availability of the draft document; (2) the beginning of a 30-day 
public comment period; and (3) an anticipated external peer-review 
workshop. EPA is extending the public comment period to October 14, 
2005, in response to requests for extension of the comment period. EPA 
intends to make comments received by the end of the extended public 
comment period (October 14, 2005) available to Versar, Inc., an EPA 
contractor for external scientific peer review, for the external peer 
review panelists prior to the anticipated workshop. The U.S. EPA will 
consider all comments received by October 14, 2005, in preparing a 
final report.
    EPA still expects Versar, Inc., to convene a panel of experts and 
organize and conduct an external peer-review workshop. This workshop 
will be announced in a separate Federal Register notice, once EPA is 
notified by Versar, Inc., of the date and location for the workshop. 
The public comment period and the external peer-review workshop are 
separate processes that will provide opportunities for all interested 
parties to comment on the document. In preparing a final report, EPA 
will consider any public comments that EPA receives in accordance with 
this notice.

DATES: The 45-day extension of the public comment period begins August 
30, 2005, and ends October 14, 2005. Technical comments should be in 
writing and must be received by EPA by close of business October 14, 
2005.

ADDRESSES: The draft document and EPA's peer-review charge are 
available primarily via the Internet on the National Center for 
Environmental Assessment's home page under the Recent Additions and 
Publications menus at http://www.epa.gov/ncea. A limited number of 
paper copies are available from the Technical Information Staff, 
National Center for Environmental Assessment; telephone: (202) 564-
3261; facsimile: (202) 565-0050. If you are requesting a paper copy, 
please provide your name, mailing address, and the document title,

[[Page 48951]]

``Approaches for the Application of Physiologically-Based 
Pharmacokinetic (PBPK) Models and Supporting Data in Risk Assessment'' 
(EPA/600/R-05/043A).
    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 OEI Docket; telephone: (202) 566-1752; facsimile: 
(202) 566-1753; or e-mail: [email protected].
    If you have questions about the document, please contact the 
Technical Information Staff, National Center for Environmental 
Assessment, U.S. Environmental Protection Agency, Washington, DC 20460; 
telephone: (202) 564-3261; facsimile: (202) 565-0050; or e-mail: 
[email protected].

SUPPLEMENTARY INFORMATION: 

I. Information About the Document

    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 pharmacokinetic 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 and exposure scenarios, and address various sources of 
uncertainty in risk assessments. This external review draft document 
addresses the following questions: (1) Why do risk assessors need PBPK 
models; (2) How can these models be used in risk assessments; and (3) 
What are the characteristics of acceptable PBPK models for use in risk 
assessment?

II. How To Submit Technical Comments to EPA's E-Docket

    EPA has established an official public docket for information 
pertaining to ``Approaches for the Application of Physiologically-Based 
Pharmacokinetic (PBPK) Models and Supporting Data in Risk Assessment'' 
(EPA/600/R-05/043A), Docket ID No. ORD-2005-0022. The official public 
docket is the collection of materials available for public viewing and 
includes the documents specifically referenced in this action, any 
public comments received, and other information related to this action, 
but excludes Confidential Business Information (CBI) or other 
information whose disclosure is restricted by statute. The official 
public docket is available for public viewing at the Office of 
Environmental Information (OEI) Docket in the Headquarters EPA Docket 
Center, (EPA/DC) EPA West Building, Room B102, 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, and the telephone number for the OEI Docket is (202) 566-
1752; facsimile: 202-566-1753; or e-mail: [email protected].
    An electronic version of the public docket is available through 
EPA's electronic public docket and comment system, E-Docket. You may 
use E-Docket at http://www.epa.gov/edocket/ to submit or view public 
comments, to access the index of the contents of the official public 
docket, and to access those documents in the public docket that are 
available electronically. Once in the system, select ``search,'' then 
key in the appropriate docket identification number.
    Certain types of information will not be placed in E-Docket. 
Information claimed as CBI and other information for which disclosure 
is restricted by statute will not be available for public viewing in 
the official public docket or in E-Docket. EPA's policy is that 
copyrighted material will not be placed in EPA's electronic public 
docket but will be referenced there and will be available as printed 
material in the official public docket.
    If you intend to submit comments to EPA, please note that it is EPA 
policy to make public comments available for public viewing as received 
at the EPA Docket Center or in E-Docket. This policy applies to 
information submitted electronically or in paper form, except where 
restricted by copyright, CBI, or statute. When EPA identifies a comment 
containing copyrighted material, EPA will provide a reference to that 
material in the version of the comment that is placed in EPA's 
electronic public docket. The entire printed comment, including the 
copyrighted material, will be available in the official public docket.
    Public comments submitted on computer disks that are mailed or 
delivered to the EPA Docket Center will be transferred to E-Docket. 
Public comments that are mailed or delivered to the EPA Docket Center 
will be scanned and placed in E-Docket. Where practical, physical 
objects will be photographed, and the photograph will be placed in E-
Docket with a brief description written by the docket staff.
    You may submit comments electronically, by mail, by facsimile, or 
by hand delivery/courier. To ensure proper receipt by EPA, include the 
appropriate docket identification number with your submission. 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.
    If you submit comments electronically, EPA recommends that you 
include your name, mailing address, and an e-mail address or other 
contact information in the body of your comment. Also include this 
contact information on the outside of any submitted disk or CD-ROM, and 
in any cover letter accompanying the disk or CD-ROM. This ensures that 
you can be identified as the person submitting the comment and allows 
EPA to contact you in case the Agency cannot read your submission due 
to technical difficulties or needs further information on the substance 
of your comment. EPA will not edit your comment, and any identifying or 
contact information provided in the body of a comment will be included 
as part of the comment that is placed in the official public docket and 
made available in E-Docket. If EPA cannot read your comment due to 
technical difficulties and cannot contact you for clarification, it may 
delay or preclude consideration of your comment.
    Electronic submission of comments to E-Docket is EPA's preferred 
method for receiving comments. Go directly to EPA Dockets at http://www.epa.gov/edocket, and follow the online instructions for submitting 
comments. To access EPA's electronic public docket from the EPA 
Internet Home Page, select ``Information Sources,'' ``Dockets,'' and 
``EPA Dockets.'' Once in the system, select ``search,'' and then key in 
Docket ID No. ORD-2005-0022. The system is an ``anonymous access'' 
system, which means EPA will not know your identity, e-mail address, or 
other contact information unless you provide it in the body of your 
comment.
    Comments may be sent by electronic mail (e-mail) to 
[email protected], Attention Docket ID No. ORD-2005-0022. In contrast 
to EPA's electronic public docket, EPA's e-mail system is

[[Page 48952]]

not an ``anonymous access'' system. If you send an e-mail comment 
directly to the docket without going through EPA's E-Docket, EPA's e-
mail system automatically captures your e-mail address, and it becomes 
part of the information in the official public docket and in E-Docket.
    You may submit comments on a disk or CD-ROM that you mail to the 
OEI Docket mailing address. Files will be accepted in WordPerfect, 
Word, or PDF format. Avoid the use of special characters and any form 
of encryption.
    If you provide comments in writing, please submit one unbound 
original with pages numbered consecutively, 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.

    Dated: August 16, 2005.
George Alapas,
Acting Director, National Center for Environmental Assessment.
[FR Doc. 05-16597 Filed 8-19-05; 8:45 am]
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