Annual Chamber Inventory and Reporting is all over the map for our industry. I’m not aware of a specific guidance that spells out how this task is accomplished and reported, but it is a GMP expectation that you control and know the number of samples in your process. It’s not unusual in the flow of Stability life with multiple transfers and LIMS “book keeping” that someone creates an error and you find your count may be off by one or two. It’s not unheard of that companies who have not prioritized good inventory practices may be starting out with errors numbering in the hundreds. The key is to have a system in place to discover and remediate discrepancies in a timely fashion. Your CAPA system should result in a downward trend in inventory errors.
Some companies perform annual inventories, some do rolling inventories (a different chamber or condition each month), and a few claim a “validated process” that doesn’t allow errors. I’ve found that “emergency inventories” like those conducted with the FDA on the doorstep, often carried out with untrained volunteer colleagues can result in even more errors than when you started. Inventorying frozen materials is problematic as well, since the process involves frequent chamber openings and some time out of refrigeration while counting.
My preference would be to conduct stability studies with samples in tamper-evident shelf cartons in predetermined numbers (such as 100 per carton) That way a count of say 479 samples would involve counting 79 samples added to 400, representing the 4 sealed (but breathable) cartons of 100 each. The inventory count is updated whenever there is a pull point. That way, each study is counted annually at a minimum and more frequently when multiple pulls may bring a higher risk of error. It also minimizes the need for extra staff required to do large scale inventories. Since the Sample handlers will already be counting the samples being removed, It only takes a few more minutes to count the remaining samples and reconcile them with the projected numbers. Any deviations get investigated and remediated, noting any emerging trends for the CAPA folks. If I were a Regulatory official, I would be impressed with any system that keeps a close eye on inventory and produces a downward trend and holds it at rock bottom for errors.
What do others in our StabilityHub community have to say on the subject?