Inadequate Sampling and Component Testing Highlighted in FDA Warning Letter

The U.S. Food and Drug Administration (FDA) has issued a Warning Letter to a U.S.-based manufacturer of over-the-counter (OTC) topical analgesic and oral care drug products, following an inspection of its Vineyard, Utah facility in December 2024. The agency cited multiple violations of current Good Manufacturing Practice (CGMP) regulations, with a particular focus on insufficient sampling and component testing practices.

Key Findings Related to Sampling and Sample Management

The deficiencies observed during the inspection point to a lack of scientifically justified sampling strategies and inadequate control over high-risk raw materials.

• Failure to perform identity testing on each component lot: The firm relied on supplier Certificates of Analysis (COAs) without verifying their reliability and failed to test incoming high-risk components such as glycerin for diethylene glycol (DEG) and ethylene glycol (EG) contamination. FDA emphasized the well-known risks of DEG and EG contamination, which have been associated with fatal poisoning incidents globally.
• Lack of representative sampling for finished products: For products like fluoride toothpaste and pain relief gel, sampling plans were not justified as representative of the entire batch. No uniformity studies or process qualification data supported the limited sampling approach. For example, only two samples were taken from a bulk batch, with one used for microbiological testing and the other for assay, despite the absence of development studies or process data supporting their representativeness.
• Inadequate water system monitoring: There was no routine testing for microbiological parameters or conductivity, and related records were missing or stored inappropriately, including on personal computers.
• Deficient sampling justifications: The firm failed to provide scientific rationale or validation for its sampling strategies, raising concerns about batch homogeneity and patient safety.

The FDA emphasized that product quality cannot be assured without robust, scientifically justified sampling and testing strategies. The agency has called on the company to implement comprehensive corrective actions, including updated procedures, expanded testing of retained samples, and a full risk assessment for distributed products.

While the company’s response included a general commitment to revise its procedures and conduct periodic verification testing, the FDA found these responses inadequate due to lack of detail, missing implementation timelines, and the absence of a retrospective review of products already distributed.

Quality Oversight and Documentation Gaps

Beyond technical deficiencies in sampling and testing, the FDA noted broad failures within the company’s Quality Unit (QU). The inspectors found shredded CGMP records in bins, missing non-conformance reports, and calibration records lacking traceability.

The lack of data to support labeled expiration dates and poor control over documentation and batch records reflected an inadequate quality system unable to ensure compliance with basic CGMP principles.

Broader Regulatory Issues

In addition to CGMP violations, the FDA noted that one product manufactured by the company was an unapproved new drug and misbranded, in violation of the FD&C Act.

The letter also reminds the company of its responsibilities as a contract manufacturer: the obligation to produce quality-compliant drugs applies regardless of any agreements with product owners.

Finally, the FDA recommended that Dynamic Blending engage an independent CGMP consultant to conduct a six-system audit and assist with remediation.

For further information, please see the complete Warning Letter to  Dynamic Blending Specialists, Inc on the FDA's website.