21 CFR 216.23
Bulk drug substances that can be used to compound drug products in accordance with section 503A of the Federal Food, Drug, and Cosmetic Act
21 CFR 216.23 is the regulation titled “Bulk drug substances that can be used to compound drug products in accordance with section 503A of the Federal Food, Drug, and Cosmetic Act” in 21 CFR Part 216, Human Drug Compounding. Since 2021, 1 FDA warning letter has cited it.
- Letters citing it
- 1 since 2021
- Jan 1 to Oct 30, 2026
- 0 against 0 on the same dates in 2025
- Most often cited with
- 21 CFR 201.115, in 1 letter
- Closed out
- 0% of these letters have a published close-out
Letters citing it, by year issued
It is a drug letter. 2026 runs to Oct 30, 2026. Pick a year to see its letters.
- 12021
- 02022
- 02023
- 02024
- 02025
- 02026
The regulation
Read the text of 21 CFR 216.23 (eCFR, as of Sep 1, 2026)
(a) The following bulk drug substances can be used in compounding under section 503A(b)(1)(A)(i)(III) of the Federal Food, Drug, and Cosmetic Act.
(1) Brilliant Blue G, also known as Coomassie Brilliant Blue G-250.
(2) Cantharidin (for topical use only).
(3) Diphenylcyclopropenone (for topical use only).
(4) N-acetyl-D-glucosamine (for topical use only).
(5) Squaric acid dibutyl ester (for topical use only).
(6) Thymol iodide (for topical use only).
(b) After balancing the criteria set forth in paragraph (c) of this section, FDA has determined that the following bulk drug substances will not be included on the list of substances that can be used in compounding set forth in paragraph (a) of this section:
(1) Oxitriptan.
(2) Piracetam.
(3) Silver Protein Mild.
(4) Tranilast.
(c) FDA will use the following criteria in evaluating substances considered for inclusion on the list set forth in paragraph (a) of this section:
(1) The physical and chemical characterization of the substance;
(2) Any safety issues raised by the use of the substance in compounded drug products;
(3) The available evidence of the effectiveness or lack of effectiveness of a drug product compounded with the substance, if any such evidence exists; and
(4) Historical use of the substance in compounded drug products, including information about the medical condition(s) the substance has been used to treat and any references in peer-reviewed medical literature.
(d) Based on evidence currently available, there are inadequate data to demonstrate the safety or efficacy of any drug product compounded using any of the drug substances listed in paragraph (a) of this section, or to establish general recognition of the safety or effectiveness of any such drug product. Any person who represents that a compounded drug made with a bulk drug substance that appears on this list is FDA approved, or otherwise endorsed by FDA generally or for a particular indication, will cause the drug to be misbranded under section 502(a) and/or 502(bb) of the Federal Food, Drug, and Cosmetic Act.
[84 FR 4710, Feb. 19, 2019]
Text from eCFR as of Sep 1, 2026.
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