The FDA issued a warning letter to Thibiant International for producing defective OTC drugs at its Newbury Park, California manufacturing facility.

The agency said the company failed to resolve significant deficiencies observed in a March 6-15, 2018 inspection. For example, the firm did not properly investigate product failures to ensure it didn’t release defective products. One batch failed at multiple stability timepoints from August 2015 to July 2017, and the out-of-specification investigation confirmed that the formulation was unstable. Despite this, the firm manufactured a second batch using the same formulation, releasing the batch with failing test results and seeing the same timepoint failures, the agency said.

The facility also lacked stability data to show an OTC drug remained acceptable throughout its labeled two-year expiration period. The firm claimed to have performed studies to support changes it made to the stability specification for an OTC drug, but it could not provide the study reports.

The firm also failed to test incoming components—such as the active ingredient zinc oxide—for quality attributes. Instead, it depended on certificates of analysis from unqualified suppliers. The company said it drafted a raw material supplier qualification procedure that would be finalized in May 2018, but it didn’t test the quality attributes of products made with the offending ingredients, the agency said.