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Effective Supply Chain Mapping Studies

Published 11 May 2015 | By Vaisala pbr

As a provider of monitoring and validation systems for regulated environments, Vaisala regulatory experts are often asked to help troubleshoot issues in pharmaceutical and medical device supply chains. In this article we answer three questions we often receive on how to perform mapping studies for regulated environments.

vaisalaQuestion 1

In qualifying conditions in a shipping container, if the size of the container is less than 20m3, how do we determine the number of monitored points and study length? Is the MTK calculation required?

Question 2

If the temperature and relative humidity outside of the shipping container should be tested as a reference, but the TEMP and RH is very different every day, and the season of shipment is unstable, how does this impact our mapping studies of shipping containers?

Question 3

For mapping studies in stability chambers and incubators, to study the effects of an open door and power failure, how do we decide the length of the study? For example, we have used study lengths of fifteen minutes, but we want to be able to justify that study length to an inspector. Can you describe how to rationalize duration?

Clarifying the Questions

For questions 1 and 2, let's first assume we are talking about a shipping container smaller than 20m3 and used for a sea shipment of temperature-sensitive, regulated products - either drugs, biotechnology, or medical devices.

incubatorsHowever, in general for Questions 1 and 2 we first must understand that mapping a shipping container at sea is quite different than mapping an incubator, stability chamber, or warehouse etc. One of the primary differences is that the shipping container cannot be controlled while it is at sea, so we consider this "temperature profiling," rather than validation/mapping.

Profiling shipping containers only help us if the container is refrigerated or air conditioned. And even then, the profiling simply identifies locations within the unit that are unsuitable for storage. For many shipping applications it's simply more effective to monitor the packages with temperature loggers designed for this purpose, rather than trying to perform a mapping study in the shipping container.

Regarding the question of how to determine study duration, there is no set duration requirement for this type of testing. It may be that we select a duration like fifteen minutes because it sounds like a good number. However, in many cases there is a better approach: test the chamber to see how long the temperatures stay in specification, and use that number when doing future deviation resolution.

Supply Chain Mapping? Not so much

Many validation professionals share the belief that these tests provide little useful information. Why? Because conditions change along the supply chain and there is no way to predict the unpredictable. This leaves us dependent upon our monitoring systems. For example, a monitoring system with door contact alarms will let you know that the door is open. A sensor inside the chamber can let you know that power has failed. Specific to stability chambers, these are units that should not be opened frequently, so these open door tests are not really applicable.

Mean Kinetic Temperature: Not for Stable Environments

coldroomGenerally speaking there is no need to use MKT calculations in a stability chamber mapping study. This is because stability chambers are supposed to be... well, stable. In learning about conditions within a given environment, we use MKT for instable environments. If you need to calculate MKT then your stability chambers aren't stable. So, you've got some bigger problems.

Validation in incubators, refrigerators, warehouses, freezers is very much the same. That said, incubators are different in one significant way; they aren't storing product. Incubators grow cultures and cultures are strongly affected by variations in temperature and humidity.Calculating MKT would probably just be indicative of a larger problem.

MKT was first developed and applied to ambient storage in warehouses. I would be very cautious trying to apply this calculation to incubators and stability chambers, as neither of these are used for finished and packaged products.

About the author
Paul Daniel is the Senior Regulatory Compliance Expert at Vaisala. With over seventeen years of validation experience in the pharmaceutical and medical device industries, and has executed a wide range of qualification projects, including: process, cleaning, shipping, laboratory equipment, packaging, software, network, and computer validation. Daniel's specialty is authoring validation protocols for pharmaceutical manufacturing and software validation with a risk-based approach drawn from GAMP guidelines. He holds a bachelor's degree in biology (with honors) from the University of California, Berkeley.