News|Videos|May 22, 2025

Ask the Expert: Quality Control Units

In this episode of the Ask the Expert video series, Susan J. Schniepp, distinguished fellow at Regulatory Compliance Associates, and Siegfried Schmitt, PhD, vice president, Technical at Parexel, discuss how to address an FDA warning letter citation for a failure to establish a quality control unit.

After an FDA inspection of a pharmaceutical manufacturing facility, any deviations the inspector might find during the inspection are reported on a Form 483 and sent to the manufacturer. If the company fails to properly respond to the agency, FDA will follow up with a warning letter. A common theme seen on warning letters is that companies fail to properly establish a quality control unit. So how should a company respond if they receive such a citation?

“Well, you see the mere fact that they actually received a warning letter means that their initial response to the observations by the FDA inspectors were considered inadequate or incomplete,” Siegfried Schmitt, vice president of Technical at Parexel, explains. “I think it's therefore essential to admit that this shortcoming has happened, and so they should make sure that the response they now give to this warning letter is really a complete and convincing one and provides a remediation plan that will be acceptable to the authorities.

In this episode of the Ask the Expert video series, Susan J. Schniepp, distinguished fellow at Regulatory Compliance Associates, and Siegfried Schmitt, PhD, vice president, Technical at Parexel, discuss what manufacturers should do when they receive a warning letter from FDA for an insufficient quality control unit.

Click the video above to watch Sue and Siegfried answer the following question:

“My company received an FDA warning letter for failure to create a quality control unit. What is the best way to respond to FDA?”

About the experts

Susan J. Schniepp is distinguished fellow at Regulatory Compliance Associates and a member of Pharmaceutical Technology®'s Editorial Advisory Board.

Siegfried Schmitt is vice president, Technical at Parexel and a member of Pharmaceutical Technology®'s Editorial Advisory Board.

Ask the Expert Video Series

Welcome to the Ask the Expert video series. This series is an extension of the PharmTech Group’s long-running print column in which industry experts answer common quality and regulatory questions from the industry. This new video series will expand on topic areas to include development and manufacturing concerns to help those working in the industry better understand bio/pharmaceutical requirements. Have a question you would like answered? Send it to PTProjects@mmhgroup.com, and it may appear in a future episode or print column.

We hope you enjoy the discussion!


Related to this article

Ask the Expert: Post-Approval Changes
In this episode of Ask the Expert, Siegfried Schmitt, PhD, vice president, Technical at Parexel, and Susan J. Schniepp, distinguished fellow at Nelson Labs, discuss how companies should approach post-approval changes to their CMC regulatory filings.
PharmTech Weekly Roundup—October 2, 2026
This week on PharmTech, Merck diversified its pipeline, USP emphasizes supply chain security, AI systems are examined, and speakers preview their presentations at CPHI Milan and AAPS PharmSci 360.
CPHI Milan 2026: Nitrosamine Risk Mitigation, Part 1
Capsugel's Bram Baert and Sandrine Picco argue that chasing zero nitrite in pharmaceutical excipients is often impractical and costly. They recommend setting scientifically justified, risk-based limits and consistently staying below them.
Regulatory Roundup—September 2026
The FDA opened an expedited IND pilot, tightened scrutiny of foreign trial data, and finalized a rule recognizing non-animal testing methods. In Europe, the EMA advanced pharmaceutical legislation reform, restricted 2 legacy products, and opened an injectable-iron safety review.