FDA Warning Letter: Missing Testing, No Stability Data, and Inadequate Raw Material Controls

On 6 June 2025, the U.S. Food and Drug Administration (FDA) issued a Warning Letter following an inspection of a drug manufacturing site in Greensboro, North Carolina, in January 2025. The facility manufactures over-the-counter (OTC) drug products, such as antibacterial soaps.

The major findings include:

• No microbiological testing of finished product batches: A batch record reviewed during the inspection indicated that the firm did not take the required sample for microbiological testing. The Warning Letter states that the company's quality assurance was unable to explain why the sample was not collected or the testing performed.
• No written stability testing program: The company lacked a written stability program to assess product quality over the intended shelf life.
• Insufficient identity testing of raw materials: Active ingredients (e.g., benzalkonium chloride) were not adequately tested for identity or microbiological quality in accordance with USP standards.

Existing procedures were described by the company itself as “not robust enough,” and the proposed corrective actions did not meet FDA expectations.

For further information, please see the complete Warning Letter to Horizon Tool Inc. on the FDA's website.