FDA Warning Letter

Regulatory Event

Thomas Brunner Hygiene GmbH, a manufacturer of over-the-counter (OTC) antiperspirant products in Albershausen, Germany, received FDA Warning Letter 320-26-106 on July 24, 2026 — issued not after an on-site inspection, but after FDA’s review of records the firm submitted in response to an August 12, 2025 request for information under section 704(a)(4) of the Federal Food, Drug, and Cosmetic Act (FD&C Act), and a separate April 2026 review of the firm’s product labeling and website. The records FDA reviewed did not include an assay test for active ingredient content in any finished drug product. Cited under 21 CFR 211.165(a), this is as close to a baseline Current Good Manufacturing Practice (CGMP) failure as exists: Thomas Brunner had no documentation showing it tested its products for identity or strength of the active ingredient before releasing them for distribution to the United States.

The firm’s own explanation, provided in its response, makes the scope of the gap explicit. Thomas Brunner stated that it considers its manufacturing processes suitable “if the final inspection result is satisfactory,” and performs no further validation activity beyond that. FDA’s letter under 21 CFR 211.100(a) and 211.67(b) confirms what that statement implies: no process validation studies, no demonstrated critical process parameters, and no validated cleaning procedures for shared, non-dedicated manufacturing equipment. A “final inspection” — visual or dimensional checks on the finished product — is not a substitute for laboratory determination of conformance to specification, and it is not process validation in any sense recognized by FDA’s 2011 Process Validation guidance, which requires demonstrated process design, process qualification, and continued verification across the product lifecycle, not a satisfactory-looking batch.

What the Record Documents

The third citation, under 21 CFR 211.84(d)(1) and (2), extends the same testing gap to raw materials. Thomas Brunner had not tested incoming glycerin — used as a component in its formulations — for identity, meaning it had no data confirming the material was free of diethylene glycol (DEG) or ethylene glycol (EG), the toxic industrial solvents responsible for a well-documented series of mass poisoning events when substituted into glycerin supply chains, including a 2006 incident traced to contaminated glycerin from China that killed more than 100 people in Panama, and more recent 2022 and 2023 events in The Gambia and Uzbekistan linked to contaminated cough syrups. This is the same specific failure mode FDA cited three days later, on July 27, 2026, in its Warning Letter to Woodbine Products Company Inc. in Ohio — a separate firm, a different product category, but an identical root cause: glycerin entering a drug manufacturing process without the United States Pharmacopeia (USP) identification test FDA’s own glycerin-testing guidance requires on every shipment of every lot. Thomas Brunner’s letter adds a second raw material gap unique to this facility: the firm could not demonstrate that the water used as a component in its products was suitable for its intended use, providing no evidence of conductivity or total organic carbon testing against the applicable USP water monograph — meaning an ingredient present in essentially every batch had never been qualified at all.

Technical and Quality Context

The fourth CGMP citation, under 21 CFR 211.166(a), found the firm’s stability program consisted of only two data sets at two temperature conditions, using test methods that FDA determined did not appear to be stability-indicating — meaning the methods used could not reliably detect degradation even if it occurred. Combined with the absence of release testing, this means Thomas Brunner had no scientific basis, at any point in the product lifecycle from manufacture through labeled expiry, for asserting that its finished products met specification.

What separates this Warning Letter from a standard CGMP citation, and what makes it genuinely instructive for formulators, is the second half of the letter: an unapproved new drug and misbranding finding tied entirely to labeling and formulation, independent of the testing gaps above. Thomas Brunner’s syNeo antiperspirant line is labeled to contain both aluminum chlorohydrate 10% and aluminum chloride 10% as active ingredients. Each ingredient, individually, is permitted under OTC Monograph M019 (Antiperspirant Drug Products for Over-the-Counter Human Use). But M019 does not permit the two in combination in a single product. Because the formulation does not conform to the monograph’s conditions of use, the products cannot rely on the OTC monograph pathway to be marketed without FDA approval, and are legally unapproved new drugs under section 505(a) of the FD&C Act and misbranded under section 502(ee). Two variants marketed with additional claims — “protect your skin from dryness and irritation” — compounded the problem by also triggering OTC Monograph M016 for skin protectants, and no monograph permits combining an antiperspirant and a skin protectant claim in one product either. This is a trap that has nothing to do with manufacturing quality and everything to do with regulatory strategy at the formulation stage: two individually generally recognized as safe and effective (GRASE) actives do not become a GRASE combination simply because each ingredient, alone, has monograph standing.

Decision Relevance

FDA closed the CGMP portion of the letter by recommending that Thomas Brunner engage a consultant qualified under 21 CFR 211.34 to assist in meeting CGMP requirements, and pointed the firm to its Quality Systems Approach to Pharmaceutical CGMP Regulations guidance alongside International Council for Harmonisation (ICH) Q9(R1) Quality Risk Management and ICH Q10 Pharmaceutical Quality System as the framework for remediation. That pairing matters: FDA is not asking Thomas Brunner to simply implement the specific tests it lacked. It is asking the firm to demonstrate, through a risk-based quality system, that it understands why release testing, process validation, and stability data exist in the first place — as interdependent evidence of a state of control, not a checklist of individually satisfiable citations. A firm that adds an assay test for active content without also building the batch-to-batch process consistency and stability program that gives that single test result any predictive value has not actually closed the gap FDA identified.