FDA Warning Letter to Turkish OTC Manufacturer

The U.S. Food and Drug Administration (FDA) sent a Warning Letter dated 13 February 2023 to a Turkish drug manufacturer.

From 12 to 16 September 2022, the FDA inspected the company's drug manufacturing facility in Istanbul. During this inspection, several violations of Current Good Manufacturing Practice (CGMP) regulations for finished pharmaceuticals were found.

Identity Testing

According to the FDA, the firm failed to adequately test incoming components for identity before using them for the production of OTC drug products. Furthermore, the company did not adequately qualify the suppliers, but nevertheless relied on the certificates of analyses (COAs) from these unqualified suppliers. As in-house testing of components for identity, purity, strength, and quality was not performed, it was not ensured that the incoming components met appropriate specifications.

Validation of Manufacturing Processes

In the Warning Letter, the FDA writes that the company did not conduct process validation studies for numerous drug products distributed to the United States. The process validation studies that were performed were considered to be inadequate by the authority. In addition, appropriate qualification of equipment used to manufacture the drug products was missing.

Stability Testing

The FDA writes that the "stability program lacked appropriate testing of [the] drug products, including testing of active ingredients, impurities, and other degradation products." That means that there is no scientific evidence that the drug products retain their quality attributes through their expiry.


The FDA has already placed the company on Import Alert 66-40 ("Detention Without Physical Examination of Drugs From Firms Which Have Not Met Drug GMPs").

As is customary in such cases, the FDA strongly recommends engaging a consultant to assist the firm in meeting CGMP requirements. The FDA recommends that this consultant should perform an audit of the entire operation for CGMP compliance.

For more information, please read the complete Warning Letter to Delta Kozmetik Sanayi Ve Ticaret-Selim Yesil, published on the FDA's website. 

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