FDA Warning Letter: Batch Release Without Appropriate Laboratory Evidence

On 24 March 2026, the U.S. Food and Drug Administration (FDA) published a new Warning Letter dated 18 March 2026.

The letter refers back to an FDA inspection conducted at a Chinese drug manufacturing facility in October 2025. FDA notes that the company had not provided a corrective action response to the cited inspectional observations and that shipments of drug products to the U.S. continued.

At the center of the letter is an analytical compliance failure frequently mentioned in Warning Letters: release decisions without appropriate laboratory evidence.

Analytical Testing

FDA criticized that release specifications and release testing were essentially limited to appearance, color, and weight checks. For an OTC drug product, FDA clearly states that: “full release testing, which includes strength and identity testing of the active ingredient, must be performed before drug product batch release and distribution.”

A second major theme is incoming material control. FDA observed that the firm did not conduct adequate identity testing on incoming components (including APIs) and relied on supplier certificates of analysis (COAs) without sufficiently establishing supplier reliability at appropriate intervals.

Process Control

According to FDA, the firm failed to adequately qualify equipment and validate the manufacturing processes used for the drug product. The Warning Letter states that the firm has “not performed process performance qualification (PPQ) studies”, nor has “a meaningful ongoing program for monitoring process control, to ensure stable manufacturing operations and consistent drug quality.”

Quality Control Unit (QU)

FDA also criticized the performance and oversight of the Quality Unit, stating there “was a fundamental failure of production management to effectively oversee the procedures, practices, and suitability of the manufacturing operations.”

In this context, FDA emphasized that QU accountability does not depend on team size: “Even when a QU consists of one or only a few, those persons are still accountable for overseeing ongoing effectiveness of all systems and procedures, and review of the results of manufacture to ensure state of control and adherence to all quality standards.”

Consultant Recommendation and Systems Approach

FDA’s recommendation to engage a qualified CGMP consultant and its references to a systems-based remediation approach signals that the agency views the deficiencies as systemic, not isolated.

For further information, please see the complete Warning Letter to Yangzhou H&R Plastic Daily Chemical Co., Ltd , published on the FDA’s website.