24/25 April 2023
In a recent FDA Warning Letter, the FDA criticized inadequate process validation for a semi-solid dosage form. What exactly did the FDA find inadequate?
The validation studies were criticized for not reflecting inter- and intra-batch variability. In particular, there was criticism that the sampling was random. The viscosity sampling scheme does not lead to statistical confidence in process performance.
In a second Process Performance Qualification (PPQ) study, the influence of a critical excipient on viscosity was to be shown. Again, the FDA criticized that no inter-batch variability was demonstrated. This is not surprising, since only one run was performed.
As measures, the FDA requires:
You can find the entire Warning Letter on the FDA website.