Standard Methods of Temperature Monitoring in Pharmaceuticals

While most products have strict temperature ranges, pharmaceuticals are extremely sensitive. It is critical to maintain a safe temperature range for vaccines and medications in transport and in storage.

Depending on the product, the safe range is either between 2°C and 8°C or between 20°C and 25°C. These temperature ranges ensure product efficacy and preserve the shelf life.

For pharmaceuticals, there is little room for error. For those products which must be stored in the lower of the two ranges, extra precaution needs to be taken. A short exposure to subzero temperature will cause permanent damage to proteins and a loss of efficacy. 

Technology can monitor the temperature of pharmaceuticals during storage. USP Chapter 1118 highlights several standard monitoring methods, including:

• Alcohol or mercury thermometers
• Chemical devices
• Chemical sensors
• Infrared devices
• Resistance temperature detectors
• Solid state devices
• Thermistors
• Thermocouples
• Thermo-mechanical devices  

How Do They Differ?

The way these methods work can vary greatly. Alcohol or mercury thermometers, for instance, are visual methods of monitoring temperature; they require you to look at the fluctuations in the volume of the liquid that’s inside them. Chemical devices are another example of a visual monitoring method. These methods look for a temperature-caused change in appearance.

Infrared devices, on the other hand, measure an article’s infrared radiation, which isn’t something you can actually observe with the naked eye. Similarly, resistance temperature detectors rely on sensitive electronics that pick up temperature-related changes in a product’s electrical resistance – again, something your eye can’t see.

However, most of these methods are antiquated and are not appropriate for modern-day pharmacy temperature monitoring. Better options are solid state devices, such as the ones we have at SmartSense, that can attain highly accurate temperature readings and provide you with a digital output.

Similarly, thermistors are semiconductor devices which are able to detect very slight changes in temperature. They are also accurate over a wider range of temperatures in comparison with other devices.

In addition, the different temperature monitoring methods can vary in the way that they operate. Some are wired to networks, for example, while some have wireless setups instead. Others are standalone data loggers that operate on old-school AC power or batteries.

Selecting the Right Method

The USP doesn’t currently mandate or recommend any method over another. You need to choose the monitoring method that is right for you and that works best for your specific needs or situation.

The USP does require the validation of your chosen method, including its measurement accuracy and measurement responsiveness. USP recommends that at least once a year, you do your validating and/or calibrating with a tool that comes from the National Institute of Standards and Technology (NIST).

Download our white paper, The Importance of Temperature Monitoring for Medication Safety and Efficacy.