Laboratory Controls in Focus in FDA Warning Letter to U.S. OTC Manufacturer

On 21 April 2026, the U.S. Food and Drug Administration (FDA) issued a new Warning Letter dated 14 April 2026, following an inspection of an OTC drug manufacturer in Palm Bay, Florida. The company manufactures OTC topical analgesic drug products.

The agency cites significant CGMP deficiencies, with a strong emphasis on laboratory control and analytical oversight.

No Finished Product Testing

A central finding: batches were released without adequate finished-product testing (identity and strength of actives, plus broader quality attributes). The firm reportedly did not perform finished-product testing prior to distribution and, while proposing to use a contract laboratory going forward, did not provide sufficient detail on implemented methods/specifications or a clear commitment to retrospective testing of retain samples already on the market.

No Assurance of the Quality of Raw Materials

FDA also criticizes weaknesses in incoming-material testing and supplier/COA qualification. The Warning Letter points to missing identity testing of components (including APIs) and reliance on supplier COAs without robust verification of their reliability. From an analytical perspective, this is a reminder that a defensible material system needs defined chemical and microbiological specifications, qualified test methods, and a documented program to validate supplier results at appropriate intervals.

Stability Program

Further, the Warning Letter addresses an inadequate stability program and raises data integrity concerns, including documentation practices that did not support reported test results. FDA requests independent assessments of laboratory practices and documentation systems, along with CAPA plans to restore control and ensure complete, reliable analytical and microbiological data.

Further Findings

The firm failed to validate the manufacturing processes for the OTC drug products. The FDA writes: "When asked to provide validation studies for your manufacturing process, you acknowledged not being familiar with process validation requirements."

In addition, the FDA mentions that the "firm failed to establish an adequate quality unit (QU) with the responsibilities and authority to oversee the manufacturing of drug products."

Beyond CGMP topics, the agency also describes the products as unapproved new drugs and misbranded, and notes a commitment to a voluntary recall of batches within expiry.

For further information, please see the complete Warning Letter to Pro Numb Tattoo Numbing Spray, LLC published on the FDA's website.