21 CFR 211.110
Sampling and testing of in-process materials and drug products
21 CFR 211.110 is the regulation titled “Sampling and testing of in-process materials and drug products” in 21 CFR Part 211, Current Good Manufacturing Practice for Finished Pharmaceuticals. Since 2021, 11 FDA warning letters have cited it.
- Letters citing it
- 11 since 2021
- Jan 1 to Oct 30, 2026
- 2 against 3 on the same dates in 2025
- Most often cited with
- 21 CFR 211.113, in 7 letters
- Closed out
- 0% of these letters have a published close-out
Letters citing it, by year issued
Most are drug letters (9 of 11). 2026 runs to Oct 30, 2026. Pick a year to see its letters.
What FDA writes when it cites it
The finding headings that cite 21 CFR 211.110 most often, as written in the letters.
- 3 lettersYour firm failed to establish and follow adequate control procedures to monitor the output and to validate the performance of those manufacturing processes that may be responsible for causing variability in the…
- 1 letterFailure to establish written procedures for production and process control designed to assure that the drug products have the identity, strength, quality, and purity that they purport or are represented to possess [21…
- 1 letterFailure to test in-process materials for identity, strength, quality, and purity, as appropriate, and approve or reject by the quality control unit, during the production process [21 CFR 211.110(c)]. For example, your…
The regulation
Read the text of 21 CFR 211.110 (eCFR, as of Sep 1, 2026)
(a) To assure batch uniformity and integrity of drug products, written procedures shall be established and followed that describe the in-process controls, and tests, or examinations to be conducted on appropriate samples of in-process materials of each batch. Such control procedures shall be established to monitor the output and to validate the performance of those manufacturing processes that may be responsible for causing variability in the characteristics of in-process material and the drug product. Such control procedures shall include, but are not limited to, the following, where appropriate:
(1) Tablet or capsule weight variation;
(2) Disintegration time;
(3) Adequacy of mixing to assure uniformity and homogeneity;
(4) Dissolution time and rate;
(5) Clarity, completeness, or pH of solutions.
(6) Bioburden testing.
(b) Valid in-process specifications for such characteristics shall be consistent with drug product final specifications and shall be derived from previous acceptable process average and process variability estimates where possible and determined by the application of suitable statistical procedures where appropriate. Examination and testing of samples shall assure that the drug product and in-process material conform to specifications.
(c) In-process materials shall be tested for identity, strength, quality, and purity as appropriate, and approved or rejected by the quality control unit, during the production process, e.g., at commencement or completion of significant phases or after storage for long periods.
(d) Rejected in-process materials shall be identified and controlled under a quarantine system designed to prevent their use in manufacturing or processing operations for which they are unsuitable.
[43 FR 45077, Sept. 29, 1978, as amended at 73 FR 51932, Sept. 8, 2008]
Text from eCFR as of Sep 1, 2026.
Cited alongside it
Regulations that appear in the same letters as 21 CFR 211.110.
- 21 CFR 211.113Control of microbiological contamination7 letters cite both
- 21 CFR 211.192Production record review6 letters cite both
- 21 CFR 211.42Design and construction features5 letters cite both
- 21 CFR 211.100Written procedures; deviations4 letters cite both
- 21 CFR 211.22Responsibilities of quality control unit4 letters cite both
- 21 CFR 211.160General requirements3 letters cite both
- 21 CFR 211.165Testing and release for distribution3 letters cite both
- 21 CFR 211.67Equipment cleaning and maintenance3 letters cite both
Latest letters citing it
The 3 letters citing 21 CFR 211.110 that FDA posted most recently.
- DrugsView Hanlim Pharm Co., Ltd.sterile (b)(4) drug productsIssuedOct 2, 2026PostedOct 13, 2026
- DrugsView Fresenius Kabi USA LLCsterile injectable drug productsIssuedSep 22, 2026PostedSep 29, 2026
- DrugsView Uriel Pharmacy, Inc.Homeopathic Ampule Drug productsIssuedOct 21, 2025PostedNov 18, 2025
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Counts include every citation in a letter, as the Letters filter does. How this database is built.