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Standardized Medicated Feed Assay Limits; Draft Guidance for Industry; Availability; Extension of Comment Period

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Food and Drug Administration, HHS.


Notice of availability; extension of comment period.


The Food and Drug Administration (FDA or Agency) is extending the comment period for the notice of availability that published in the Federal Register on February 27, 2020. In that notice, FDA requested comments on the draft guidance for industry (GFI) #264 entitled “Standardized Medicated Feed Assay Limits.” The Agency is taking this action in response to a request for an extension to allow interested persons additional time to submit comments.


FDA is extending the comment period on the document published February 27, 2020 (85 FR 11369). Submit either electronic or written comments on the draft guidance by June 26, 2020, to ensure that the Agency considers your comments on this draft guidance before it begins work on the final version of the guidance.


You may submit comments on any guidance at any time as follows:

Electronic Submissions

Submit electronic comments in the following way:

  • Federal eRulemaking Portal: Follow the instructions for submitting comments. Comments submitted electronically, including attachments, to 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 Start Printed Page 23370third 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
  • 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:

  • 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.
  • 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-2019-D-5664 for “Standardized Medicated Feed Assay Limits.” Received comments will be placed in the docket and, except for those submitted as “Confidential Submissions,” publicly viewable at or at the Dockets Management Staff between 9 a.m. and 4 p.m., Monday through Friday.

  • Confidential Submissions—To submit a comment with confidential 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 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:​content/​pkg/​FR-2015-09-18/​pdf/​2015-23389.pdf.

Docket: For access to the docket to read background documents or the electronic and written/paper comments received, go to 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.

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Katie Ciesienski, Center for Veterinary Medicine (HFV-141), Food and Drug Administration, 7500 Standish Pl., Rockville, MD 20855, 240-402-0676,

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In the Federal Register of February 27, 2020, FDA published a notice announcing the availability of draft GFI #264 entitled “Standardized Medicated Feed Assay Limits” with a 60-day comment period. This draft guidance recommends a standardized set of assay limits for medicated feeds. Standardized medicated feed assay limits allow predictability in the review process as the sponsor can determine early in the drug development process what assay limits they should expect to meet for medicated feeds used in Target Animal Safety, Effectiveness, Chemistry, Manufacturing, and Controls, Bioequivalence, and Human Food Safety residue chemistry studies. Assay limits are used pre-approval to ensure that medicated feeds in these studies contain the appropriate amount of drug, and post-approval for compliance and customer service purposes.

The Agency has received a request for a 90-day extension of the comment period. The request conveyed concern that the current 60-day comment period does not allow sufficient time to develop a comprehensive response.

FDA has considered the request and is extending the comment period for the notice of availability for 60 days, until June 26, 2020. The Agency believes that a 60-day extension allows adequate time for interested persons to submit comments.

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Dated: April 21, 2020.

Lowell J. Schiller,

Principal Associate Commissioner for Policy.

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[FR Doc. 2020-08890 Filed 4-24-20; 8:45 am]