Signature Formulations, LLC – FDA Warning Letter, Jul 29, 2025

The FDA issued a Warning Letter to Signature Formulations, LLC, following an inspection of their Phoenix, AZ drug manufacturing facility from July 21 to 29, 2025. The letter outlines significant violations of Current Good Manufacturing Practice (CGMP) regulations (21 CFR parts 210 and 211), leading to the conclusion that the company's drug products are adulterated. Key violations included the firm's failure to prevent cross-contamination, specifically involving potent hormones used in shared equipment for over-the-counter drug products. This inadequacy led to a voluntary recall of certain ORL Kids products. Furthermore, Signature Formulations failed to establish adequate cleaning validation procedures for shared equipment and released finished drug products without sufficient laboratory testing for identity, strength, purity, and microbiological quality. The company also lacked an effective Quality Unit, demonstrating inadequate oversight of critical operations such as raw material testing, process controls, investigations, and stability studies. The FDA requires Signature Formulations to undertake several corrective actions, including comprehensive, independent assessments of their manufacturing operations, cross-contamination hazards, and laboratory practices. They must implement robust testing plans for all drug products, provide a detailed risk assessment for potentially contaminated distributed products, and establish a fully functional Quality Unit. Given previous similar violations cited in 2018, the firm is strongly recommended to engage a qualified drug law consultant to perform a comprehensive six-system audit to address these systemic issues and ensure ongoing CGMP compliance.