Notice2026-05275
Physicochemical and Structural (Q3) Characterization of Topical Drug Products Submitted in Abbreviated New Drug Applications; Guidance for Industry, Availability
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Published
March 18, 2026
Issuing agencies
Health and Human Services DepartmentFood and Drug Administration
Abstract
The Food and Drug Administration (FDA or Agency) is announcing the availability of a final guidance for industry entitled "Physicochemical and Structural (Q3) Characterization of Topical Drug Products Submitted in ANDAs." This guidance is intended to assist applicants who submit abbreviated new drug applications (ANDAs) for liquid-based and/or other semisolid products applied to the skin, including integumentary and mucosal (e.g., vaginal) membranes (referred to as "topical products"). This guidance provides recommendations for physicochemical and structural (collectively, "Q3") characterizations that can be used to identify the dosage form of a proposed generic (test) topical product, and to describe properties of the drug product that may be critical to its performance (to support a demonstration of bioequivalence (BE)). This guidance finalizes the draft guidance of the same title issued on October 21, 2022.
Full Text
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<title>Federal Register, Volume 91 Issue 52 (Wednesday, March 18, 2026)</title>
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[Federal Register Volume 91, Number 52 (Wednesday, March 18, 2026)]
[Notices]
[Pages 13039-13041]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-05275]
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DEPARTMENT OF HEALTH AND HUMAN SERVICES
Food and Drug Administration
[Docket No. FDA-2022-D-1864]
Physicochemical and Structural (Q3) Characterization of Topical
Drug Products Submitted in Abbreviated New Drug Applications; Guidance
for Industry, Availability
AGENCY: Food and Drug Administration, HHS.
ACTION: Notice of availability.
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SUMMARY: The Food and Drug Administration (FDA or Agency) is announcing
the availability of a final guidance for industry entitled
``Physicochemical and Structural (Q3) Characterization of Topical Drug
Products Submitted in ANDAs.'' This guidance is intended to assist
applicants who submit abbreviated new drug applications (ANDAs) for
liquid-based and/or other semisolid products applied to the skin,
including integumentary and mucosal (e.g., vaginal) membranes (referred
to as ``topical products''). This guidance provides recommendations for
physicochemical and structural (collectively, ``Q3'') characterizations
that can be used to identify the dosage form of a proposed generic
(test) topical product, and to describe properties of the drug product
that may be critical to its performance (to support a demonstration of
bioequivalence (BE)). This guidance finalizes the draft guidance of the
same title issued on October 21, 2022.
DATES: The announcement of the guidance is published in the Federal
Register on March 18, 2026.
ADDRESSES: You may submit either electronic or written comments on
Agency guidance at any time as follows:
Electronic Submissions
Submit electronic comments in the following way:
<bullet> Federal eRulemaking Portal: <a href="https://www.regulations.gov">https://www.regulations.gov</a>.
Follow the instructions for submitting comments. Comments submitted
electronically, including attachments, to <a href="https://www.regulations.gov">https://www.regulations.gov</a>
will be posted to the docket unchanged. Because your comment will be
made public, you are solely responsible for ensuring that your comment
does not include any confidential information that you or a third party
may not wish to be posted, such as medical information, your or anyone
else's Social Security number, or confidential business information,
such as a manufacturing process. Please note that if you include your
name, contact information, or other information that identifies you in
the body of your comments, that information will be posted on <a href="https://www.regulations.gov">https://www.regulations.gov</a>.
<bullet> If you want to submit a comment with confidential
information that you do not wish to be made available to the public,
submit the comment as a written/paper submission and in the manner
detailed (see ``Written/Paper Submissions'' and ``Instructions'').
Written/Paper Submissions
Submit written/paper submissions as follows:
<bullet> Mail/Hand Delivery/Courier (for written/paper
submissions): Dockets Management Staff (HFA-305), Food and Drug
Administration, 5630 Fishers Lane, Rm. 1061, Rockville, MD 20852.
<bullet> For written/paper comments submitted to the Dockets
Management Staff, FDA will post your comment, as well as any
attachments, except for information submitted, marked and identified,
as confidential, if submitted as detailed in ``Instructions.''
Instructions: All submissions received must include the Docket No.
FDA-2022-D-1864 for ``Physicochemical and Structural (Q3)
Characterization of Topical Drug Products Submitted in ANDAs.''
Received comments will be placed in the docket and, except for those
submitted as ``Confidential Submissions,'' publicly viewable at <a href="https://www.regulations.gov">https://www.regulations.gov</a> or at the Dockets Management Staff between 9 a.m.
and 4 p.m., Monday through Friday, 240-402-7500.
<bullet> Confidential Submissions--To submit a comment with
confidential
[[Page 13040]]
information that you do not wish to be made publicly available, submit
your comments only as a written/paper submission. You should submit two
copies total. One copy will include the information you claim to be
confidential with a heading or cover note that states ``THIS DOCUMENT
CONTAINS CONFIDENTIAL INFORMATION.'' The Agency will review this copy,
including the claimed confidential information, in its consideration of
comments. The second copy, which will have the claimed confidential
information redacted/blacked out, will be available for public viewing
and posted on <a href="https://www.regulations.gov">https://www.regulations.gov</a>. Submit both copies to the
Dockets Management Staff. If you do not wish your name and contact
information to be made publicly available, you can provide this
information on the cover sheet and not in the body of your comments and
you must identify this information as ``confidential.'' Any information
marked as ``confidential'' will not be disclosed except in accordance
with 21 CFR 10.20 and other applicable disclosure law. For more
information about FDA's posting of comments to public dockets, see 80
FR 56469, September 18, 2015, or access the information at: <a href="https://www.govinfo.gov/content/pkg/FR-2015-09-18/pdf/2015-23389.pdf">https://www.govinfo.gov/content/pkg/FR-2015-09-18/pdf/2015-23389.pdf</a>.
Docket: For access to the docket to read background documents or
the electronic and written/paper comments received, go to <a href="https://www.regulations.gov">https://www.regulations.gov</a> and insert the docket number, found in brackets in
the heading of this document, into the ``Search'' box and follow the
prompts and/or go to the Dockets Management Staff, 5630 Fishers Lane,
Rm. 1061, Rockville, MD 20852, 240-402-7500.
You may submit comments on any guidance at any time (see 21 CFR
10.115(g)(5)). Submit written requests for single copies of this
guidance to the Division of Drug Information, Center for Drug
Evaluation and Research, Food and Drug Administration, 10001 New
Hampshire Ave., Hillandale Building, 4th Floor, Silver Spring, MD
20993-0002. Send one self-addressed adhesive label to assist that
office in processing your requests. See the SUPPLEMENTARY INFORMATION
section for electronic access to the guidance document.
FOR FURTHER INFORMATION CONTACT: Rachel Erdman, Center for Drug
Evaluation and Research, Food and Drug Administration, 10903 New
Hampshire Ave., Bldg. 75, Rm. 1715, Silver Spring, MD 20993-0002, 301-
348-3984, <a href="/cdn-cgi/l/email-protection#e8ba898b808d84c6ad9a8c858986a88e8c89c680809bc68f879e"><span class="__cf_email__" data-cfemail="f2a093919a979edcb780969f939cb2949693dc9a9a81dc959d84">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION:
I. Background
FDA is announcing the availability of a guidance for industry
entitled ``Physicochemical and Structural (Q3) Characterization of
Topical Drug Products Submitted in ANDAs.'' This guidance is intended
to assist applicants who submit ANDAs for liquid-based and/or other
semisolid products applied to the skin, including integumentary and
mucosal (e.g., vaginal) membranes. This guidance document provides
recommendations for physicochemical and structural (collectively,
``Q3'') characterizations that can be used: (1) to identify the dosage
form of a proposed generic (test) topical product and (2) to describe
properties of the drug product that may be critical to its performance
(to support a demonstration of BE). This guidance does not address Q3
characterization of topical products for purposes of product quality
control.
Basic Q3 characterization of a topical product can be used to
describe its dosage form (e.g., an emulsion). The nomenclature used to
describe the dosage form of topical products (e.g., solutions,
suspensions, gels, lotions, creams, shampoos, ointments, pastes, etc.)
is not precisely defined by a systematic classification of the
compositional, physicochemical, or structural attributes of the drug
product. Consequently, for topical products, it may not be possible to
infer the Q3 attributes of a particular dosage form based upon the
dosage form nomenclature.
Comprehensive Q3 characterization of a topical product can be used
to establish a detailed profile of Q3 attributes that specifically
describes the nature of that product and identifies a collection of
attributes that describe the arrangement of matter (e.g., the
polymorphic form(s) of the active ingredient(s) and/or the pH of the
drug product) that may modulate the systemic or local availability of
the active ingredient(s) from the product. Because Q3 characterization
describes essential attributes of a drug product that may be critical
to its performance, differences in Q3 attributes between a test product
and the reference standard selected by FDA can indicate a risk that the
differences may impact the respective bioavailability and/or BE of the
two products. Conversely, a demonstration that there are no differences
in Q3 attributes between a test and reference standard substantially
mitigates the risk of potential failure modes for BE that may otherwise
arise from any differences in Q3 attributes.
This guidance provides recommendations on the types of
characterizations that constitute a basic and comprehensive Q3
characterization. This guidance also describes the concepts of
``sameness,'' ``similarity,'' and ``difference'' in comparing Q3
characterizations of two topical products, and how a showing of ``Q3
sameness,'' ``Q3 similarity,'' or ``Q3 difference'' between a test
topical product and the reference standard may impact what additional
evidence may be recommended to demonstrate BE, as part of a comparative
product characterization-based approach.
This guidance finalizes the draft guidance entitled
``Physicochemical and Structural (Q3) Characterization of Topical Drug
Products Submitted in ANDAs'' issued on October 24, 2022 (87 FR 64230).
FDA received no comments on the draft guidance. Editorial changes were
made to improve clarity.
This guidance is being issued consistent with FDA's good guidance
practices regulation (21 CFR 10.115). This guidance represents the
current thinking of FDA on ``Physicochemical and Structural (Q3)
Characterization of Topical Drug Products Submitted in ANDAs.'' It does
not establish any rights for any person and is not binding on FDA or
the public. You can use an alternative approach if it satisfies the
requirements of the applicable statutes and regulations.
II. Paperwork Reduction Act of 1995
While this guidance contains no collection of information, it does
refer to previously approved FDA collections of information. The
previously approved collections of information are subject to review by
the Office of Management and Budget (OMB) under the Paperwork Reduction
Act of 1995 (PRA) (44 U.S.C. 3501-3521). The collections of information
in 21 CFR part 314 relating to abbreviated new drug applications
(ANDAs) have been approved under OMB control number 0910-0001. The
collections of information in 21 CFR part 314 for controlled
correspondence related to generic drug development is approved under
OMB control number 0910-0727. The collections of information in 21 CFR
part 58 that support Good Laboratory Practice (GLP) for Nonclinical
Laboratory Studies have been approved under OMB control number 0910-
0119. The collections of information in 21 CFR parts 312 and 320
pertaining to Investigational New Drug Safety Reporting Requirements
involving Bioavailability and Bioequivalence Studies in Humans have
been approved under OMB control number 0910-0014. The collections of
information in 21 CFR 211.170 for recordkeeping requirements relating
to
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Current Good Manufacturing Practice (CGMP) sample retention have been
approved under OMB control number 0910-0139.
III. Electronic Access
Persons with access to the internet may obtain the guidance at
<a href="https://www.fda.gov/drugs/guidance-compliance-regulatory-information/guidances-drugs">https://www.fda.gov/drugs/guidance-compliance-regulatory-information/guidances-drugs</a>, <a href="https://www.fda.gov/regulatory-information/search-fda-guidance-documents">https://www.fda.gov/regulatory-information/search-fda-guidance-documents</a>, or <a href="https://www.regulations.gov">https://www.regulations.gov</a>.
Grace R. Graham,
Deputy Commissioner for Policy, Legislation, and International Affairs.
[FR Doc. 2026-05275 Filed 3-17-26; 8:45 am]
BILLING CODE 4164-01-P
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