Mexican API Manufacturer receives Warning Letter
Recommendation

18 June 2026
Regulatory framework, interfaces and practical implications
The Mexican API manufacturer "Signa SA de CV" received a Warning Letter from the US FDA in July 2020.
This Warning Letter highlighted in particular the infringements in the area of quality control. According to the US FDA, the procedures for correction and prevention (CAPAs) of OOS results were not sufficient. In addition, according to the Warning Letter, the manufacturer has failed to establish and substantiate adequate solution approaches to determine the cause of the OOS results.
Furthermore, the agency noted that they had found similar deficiencies during inspections conducted in other manufacturing plants of the company group. This prompted the US FDA to state that the cGMP-compliant manufacture and testing of the products by the company management was not guaranteed and therefore the quality management overview was insufficient, especially in the area of quality control.
The complete list of deficiencies along with the recommendations and specifications of the US FDA to remedy these deficiencies can be found in the Warning Letter Signa SA de CV.
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