Temperature mapping, or thermal mapping as it is also known, provides food and pharmaceutical companies with the confidence that their storage conditions comply with regulatory requirements. Even minor fluctuations in temperature could lead to product safety and compliance issues meaning that costly inventory is lost.
Periodic temperature mapping of storage conditions is critical for compliance in MHRA or FDA regulated applications. Compliance means there is increased emphasis on the need to perform GMP mapping on temperature controlled storage where drugs, vaccines and other pharmaceutical products are stored and it can be a requirement for licencing a product.
When to Map
The temperature mapping of storage areas should be carried out before the storage area is used. In fact, GDP Guidelines Chapter 3.2.1 quote:
“An initial temperature mapping exercise should be carried out on the storage area before use, under representative conditions.”
The MHRA states that it has become apparent during inspections that some companies are unclear as to what is expected of them to comply with this requirement in the GDP Guidelines.
When an Operation Qualification (OQ) map takes place, the chamber must be empty. For most pharmaceutical and biotechnical applications, both an (OQ) and Performance Qualification (PQ) are important. PQ tests are mapped when the chamber is full of product.
Whether the mapping exercise falls under OQPQ procedures or not, an empty storage area that has been mapped, should have another temperature mapping exercise carried out once the inventory is in place to establish that temperatures are being maintained without any hot or cold spots.
As well as temperature mapping as a new area is commissioned, temperature mapping should also take place at the height of seasonal variations. For instance, during a cold spell in winter or in a very warm summer week. If storage temperatures remain within limits during these extreme conditions, there is an increased probability that they will do so throughout the year.
Whenever there are any modifications made to the storage facility or the temperature controlling equipment, a mapping exercise should be undertaken.
How to Map
Typically, a temperature mapping exercise would run for 7 days in a large ambient or chilled storage facility. For smaller chiller units a period of 48 to 72 hours is usually sufficient.
Before mapping, there are some points to consider.
Where is the highest point of storage?
Where are items such as heaters, coolers, windows, doors and loading bays that could cause temperature fluctuations located?
Have additional areas such as packing and returns departments or mezzanine storage floors been included?
Once the total storage area for temperature mapping has been planned, the required number of calibrated devices such as data loggers can be established.
Data loggers should be distributed evenly across the area to be mapped in a grid formation. They are used to monitor the corners of the area and should also be placed any worse case places for heat loss or variation.
It is typical to use two layers of loggers, with one logger near each corner and another central logger. However, this varies depending on the size of the temperature mapping area.
Mapping is only required in the areas such as racks, shelves and other storage areas where product is located.
Reporting and Assessing the Data
Once the temperature mapping exercise is completed, the data may show that permanent temperature monitoring equipment should be moved so they are positioned in areas that experience extremes of fluctuations. These areas are those where product is most vulnerable when temperatures go out of limits.
The exercise may also identify areas that are unsuitable to store drugs and vaccines and the storage racks may need to be relocated to a more manageable area.
Temperature mapping is integral to the validation process that is an important element of a successful compliance strategy. It demonstrates that the environment is suitable for sensitive products and compliant with Good Manufacturing Practice.
Taking a stringent approach to temperature validation ensures that any auditor or inspector can immediately see that environmental control procedures are in place when they visit your facility.