Warning letter to Topical Products Manufacturer

Recommendation
18-20 November 2025
Heidelberg, Germany
GMP and FDA Compliance in Pharmaceutical Development and IMP Manufacturing
Due to GMP violations and misbranding of products the U.S. Food and Drug Administration, FDA, issued a Warning Letter to a topical product manufacturer in Hong Kong.
During FDA´s inspection in September 2017, the authority observed specific GMP violations including, but not limited to, the following:
- Microbial limit tests: the manufacturer did not perform tests for each batch of topical product before releasing each batch. Instead, the manufacturer performed microbial limit testing on one batch only, and reported the same results to release subsequently-manufactured batches.
- Process validation: the processes used to manufacture the topical drug products were not validated. The manufacturer also lacked an ongoing programme for monitoring process control to ensure stable manufacturing operations and consistent drug quality.
- Testing of raw materials: the manufacturer did not test incoming active pharmaceutical ingredients and other components for identity, purity, strength, and quality prior to use in the drug manufacturing process.
- Stability data: drug products were labeled with an expiration date without adequate stability data to support the assigned expiration date of these drug products.
The FDA issued the Warning Letter since the manufacturer´s response to the GMP observations was inadequate (it did not provide sufficient evidence of corrective actions to bring operations into compliance with GMP).
In addition, the manufacturer misbranded drug products. Specifically, as formulated and labeled:
- Labels failed to declare active ingredients, the proportion of each active ingredient, and inactive ingredients.
- Ingredients were used as active ingredients, but are not declared as active ingredients on the product labels.
- The firm was unable to provide a complete list of all excipients, and not all excipients were declared on the product labels.
- The products’ labeling failed to bear all of the required warnings (for example: “Do not use otherwise than as directed”).
For more information please see the original FDA Warning Letter to Nan San (HK) Pharmaceutical Factory Ltd. on the FDA website.
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