“When everything is critical, nothing is critical”
So goes the saying…
And indeed, it’s a tough conundrum- because in Pharma, we have to define EXACTLY what it is that we are going to do, in writing, to comply with GMP.
So when we lock our batch records and submit the manufacturing process to the regulatory authorities, we are committed to the ranges we submit, and everything becomes “critical”.
Working outside these ranges would result in a deviation, and potentially impact our product.
But this is not the kind of “critical” ICH Q8 is talking about.
Critical is what impacts the safety and efficacy of the product- and in order to establish that, we must follow through with the enhanced approach of Quality by Design.
By understanding criticality from the lens of impact to product’s Critical Quality Attributes (CQAs), we are able to define a risk-based control strategy (and wider ranges where possible).
This allows us more operational flexibility and less unnecessary failure- while adhering to the process we are committed to.
So in a GMP process, to paraphrase: “All parameters are critical, but some are more critical than others”.