Skip to Content

We invite you to try out our new beta eCFR site at We’ve made big changes to make the eCFR easier to use. Be sure to leave feedback using the 'Feedback' button on the bottom right of each page!

The Office of the Federal Register will be closed Friday, June 18, 2021, in observance of Juneteenth National Independence Day. We will reopen on Monday, June 21, 2021, at 8:45am.


Q3C(R8) Recommendations for the Permitted Daily Exposures for Three Solvents-2-Methyltetrahydrofuran, Cyclopentyl Methyl Ether, and Tert-Butyl Alcohol-According to the Maintenance Procedures for the Guidance Q3C Impurities: Residual Solvents; International Council for Harmonisation; Draft Guidance for Industry; Availability

This document has a comment period that ends in 1134 days. (07/26/2024) Submit a formal comment

Thank you for taking the time to create a comment. Your input is important.

Once you have filled in the required fields below you can preview and/or submit your comment to the Health and Human Services Department for review. All comments are considered public and will be posted online once the Health and Human Services Department has reviewed them.

You can view alternative ways to comment or you may also comment via at,

  1. Note: You can attach your comment as a file and/or attach supporting documents to your comment. Attachment Requirements.

  2. this will NOT be posted on

  3. An Individual

    An Organization


  1. Preview Comment
Please review the privacy notice and user notice .

This document was corrected by a document published on 06/05/2020. View Correction

Document Details

Information about this document as published in the Federal Register.

Document Statistics
Document page views are updated periodically throughout the day and are cumulative counts for this document. Counts are subject to sampling, reprocessing and revision (up or down) throughout the day.
Enhanced Content

Relevant information about this document from provides additional context. This information is not part of the official Federal Register document.

Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

Start Preamble


Food and Drug Administration, HHS.


Notice of availability.


The Food and Drug Administration (FDA or Agency) is announcing the availability of draft recommendations for new permitted daily exposures (PDEs) for the residual solvents 2-methyltetrahydrofuran, cyclopentyl methyl ether, and tert-butyl alcohol. The PDEs were developed according to the methods for establishing exposure limits included in the guidance for industry entitled “Q3C Impurities: Residual Solvents.” The recommendations were prepared under the auspices of the International Council for Harmonisation (ICH), formerly the International Conference on Harmonisation. The draft guidance is intended to recommend acceptable amounts for the listed residual solvents in pharmaceuticals for the safety of patients.


Submit either electronic or written comments on the draft guidance by July 26, 2024 to ensure that the Agency considers your comment 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 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
  • 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-2020-D-1301 for “Q3C(R8) Recommendations for the Permitted Daily Exposures for Three Solvents—2-Methyltetrahydrofuran, Cyclopentyl Methyl Ether, and Tert-Butyl Alcohol—According to the Maintenance Procedures for the Guidance Q3C Impurities: Residual Solvents.” 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.

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, or the Office of Communication, Outreach and Development, Center for Biologics Evaluation and Research (CBER), Food and Drug Administration, 10903 New Hampshire Ave., Bldg. 71, Rm. 3128, Silver Spring, MD 20993-0002. Send one self-addressed adhesive label to assist that office in processing your requests. The guidance may also be obtained by mail by calling CBER at 1-Start Printed Page 31786800-835-4709 or 240-402-8010. See the SUPPLEMENTARY INFORMATION section for electronic access to the guidance document.

Start Further Info


Regarding the guidance: Timothy McGovern, Center for Drug Evaluation and Research, Food and Drug Administration, 10903 New Hampshire Ave., Bldg. 22, Rm. 6426, Silver Spring, MD 20993-0002, 240-402-0477; or Stephen Ripley, Center for Biologics Evaluation and Research, Food and Drug Administration, 10903 New Hampshire Ave., Bldg. 71, Rm. 7301, Silver Spring, MD 20993-0002, 240-402-7911.

Regarding the ICH: Amanda Roache, Center for Drug Evaluation and Research, Food and Drug Administration, 10903 New Hampshire Ave., Bldg. 51, Rm. 6364, Silver Spring, MD 20993-0002, 301-796-4548,

End Further Info End Preamble Start Supplemental Information


I. Background

In recent years, regulatory authorities and industry associations from around the world have participated in many important initiatives to promote international harmonization of regulatory requirements under the ICH. FDA has participated in several ICH meetings designed to enhance harmonization and is committed to seeking scientifically based harmonized technical procedures for pharmaceutical development. One of the goals of harmonization is to identify and reduce differences in technical requirements for drug development among regulatory agencies.

ICH was established to provide an opportunity for harmonization initiatives to be developed with input from both regulatory and industry representatives. FDA also seeks input from consumer representatives and others. ICH is concerned with harmonization of technical requirements for the registration of pharmaceutical products for human use among regulators around the world. The six founding members of the ICH are the European Commission; the European Federation of Pharmaceutical Industries Associations; FDA; the Japanese Ministry of Health, Labour, and Welfare; the Japanese Pharmaceutical Manufacturers Association; and the Pharmaceutical Research and Manufacturers of America. The Standing Members of the ICH Association include Health Canada and Swissmedic. Any party eligible as a Member in accordance with the ICH Articles of Association can apply for membership in writing to the ICH Secretariat. The ICH Secretariat, which coordinates the preparation of documentation, operates as an international nonprofit organization and is funded by the Members of the ICH Association.

The ICH Assembly is the overarching body of the Association and includes representatives from each of the ICH members and observers. The Assembly is responsible for the endorsement of draft guidelines and adoption of final guidelines. FDA publishes ICH guidelines as FDA guidance.

In the Federal Register of December 24, 1997 (62 FR 67377), FDA published a notice announcing the availability of the ICH guidance for industry entitled “Q3C Impurities: Residual Solvents.” The guidance makes recommendations as to what amounts of residual solvents are considered toxicologically acceptable for some residual solvents, or permitted daily exposure. Upon issuance in 1997, the text and appendix 1 of the guidance contained several tables and a list of solvents categorizing residual solvents by toxicity, classes 1 through 3, with class 1 being the most toxic. The ICH Quality Expert Working Group (EWG) agreed that the PDEs could be modified if reliable and more relevant toxicity data were brought to the attention of the group and the modified PDE could result in a revision of the tables and list.

In 1999, ICH instituted a Q3C maintenance agreement and formed a maintenance EWG (the Q3C EWG). The agreement provided for the revisitation of solvent PDEs and allowed for minor changes to the tables and list that include the existing PDEs. The agreement also provided for new solvents and PDEs that could be added to the tables and list based on adequate toxicity data. In the Federal Register of February 12, 2002 (67 FR 6542), FDA briefly described the process for proposing future revisions to the PDEs. In the same notice, the Agency announced its decision to remove the link to the tables and list in the Q3C guidance and create a stand-alone document entitled “Q3C: Tables and List” to facilitate making changes recommended by ICH; the document is available at​downloads/​drugs/​guidancecomplianceregulatoryinformation/​guidances/​ucm073395.pdf. “Q3C: Tables and List” was updated in January 2017 to include the recommended PDE for triethylamine and methylisobutylketone.

In March 2020, the ICH Assembly endorsed the draft PDEs for three solvents—2-methyltetrahydrofuran, cyclopentyl methyl ether, and tert-butyl alcohol—and agreed that the guidance should be made available for public comment. The draft guidance is the product of the ICH Q3C EWG. Comments on this draft will be considered by FDA and the Quality EWG.

This draft guidance has been left in the original ICH format. The final guidance will be reformatted and edited to conform with FDA's good guidance practices regulation (21 CFR 10.115) and style before publication. The draft guidance, when finalized, will represent the current thinking of FDA on the PDEs for 2-methyltetrahydrofuran, cyclopentyl methyl ether, and tert-butyl alcohol. 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

This draft guidance refers to previously approved FDA collections of information. These collections of information are subject to review by the Office of Management and Budget (OMB) under the Paperwork Reduction Act of 1995 (44 U.S.C. 3501-3521). The collections of information in 21 CFR part 58 pertaining to good laboratory practice for nonclinical laboratory studies have been approved under OMB control number 0910-0119.

III. Electronic Access

Persons with access to the internet may obtain the draft guidance at,​drugs/​guidance-compliance-regulatory-information/​guidances-drugs, or​vaccines-blood-biologics/​guidance-compliance-regulatory-information-biologics/​biologics-guidances.

Start Signature

Dated: May 19, 2020.

Lowell J. Schiller,

Principal Associate Commissioner for Policy.

End Signature End Supplemental Information

[FR Doc. 2020-11280 Filed 5-26-20; 8:45 am]