Do you NEED to map empty chambers?
When is Empty Chamber Mapping really a Worst Case Scenario Equipment Qualification?
Piritta Maunu received this question by email and answers in this week's blog.
According to best practice, at least empty and full load mapping should be performed. From a qualification perspective, the empty mapping would occur in the Operational Qualification (OQ) verification and the loaded chambers would occur in the Performance Qualification (PQ) verification.
An empty load is thus called a worst case testing scenario and represents the best challenge practice for the equipment you are mapping. In practice, we find that air temperature is always the best challenge when dealing with storage. Here is an article from my colleague Paul Daniel where he discusses in-air vs. in-media mapping. And, here Paul discusses the USP recommendations on load percentage.
It's the fluctuations that count...
Once the system reaches equilibrium, the air will always have more temperature fluctuations than the product. If you can show that you have control of the air temperature, then you know you can control the temperature of the product, no matter the size, dosage, etc. However, this may differ depending on the use case. Some companies find good reasons to support mapping only empty chambers, as they think this represents the best overall challenge. If your system is expected (or known) to perform differently with different loads, then that would justify qualifying multiple loads.multiple loads.
Develop and document your rationale
Whatever you choose, you'll need a rationale that is supported by how the equipment is used and the requirements of the products. For example, in mapping equipment based on convection (blowing air), the chambers work better when the air is free to move around the area. Here a full load may actually be the best challenge of a worst case scenario. Likewise, we need to remember also that freezers (-80˚C) e.g. work better with the load than without it (based on conduction).
It follows that the worst case scenario for mapping ultra-low freezers is definitely the empty load. This example makes you think that you need to understand your processes and equipment to find out the best solutions for your testing needs.
I hope that my answer is helpful! Please don’t hesitate to contact me and/or Paul Daniel. We will do our best to respond as quickly as possible!
More on Mapping Worst Case Scenarios & Regulatory Stuff you Should Read
To learn more about mapping your worst-case scenarios, we have this article.
Further Reading from ICH & PIC/S:
Here are some great resources on validation to review and reference in your mapping documents:
The ICH Q7 Good Manufacturing Practice Guide for Active Pharmaceutical Ingredients. ICH Harmonized Tripartite Guideline 2000 (Q7a) requires that facilities, systems, equipment and utilities are properly qualified and maintained to assure data and product integrity. Additional guidance is provided by the Pharmaceutical Inspection Co-operation Scheme PIC/S Recommendations contained in the document: "Good Practices for Computerised Systems in Regulated GxP Environments" (2007) in the section: "Validation Strategies And Priorities."