Pharmaceutical Products fall under some of the most stringent regulations of any manufactured goods out there. Product testing against varying environmental conditions need to be recorded using both accurate temperature-humidity sensors and reliable data logging software.

Such process control testing is referred to as stability testing because test materials are analysed for any degradation or significant physical changes throughout various temperature and relative humidity settings.

The stability of a pharmaceutical product is a measure of its ability to resist deterioration during the period within which its properties and characteristics can be expected to remain with certain limits. All articles intended for use in diagnosis, mitigation, treatment of prevention of disease undergo some form of testing, often multiple times in the product development cycle, from drug development to package selection.

Temperature-humidity sensors are just one portion of a stability testing system. Older more cumbersome systems make use of large environmental chambers to contain all the test samples. The disadvantages of environmental chambers are that you can only test the samples for one temperature and relative humidity setting in equipment that takes up a lot space and has high running costs. Modern bench-top stability testing units or "small scale stability testing units" allow for many different temperature-humidity sensor readings to be logged at the same time in a relatively small amount of physical space.

Calibration requirements for temperature-humidity sensors

Generally speaking temperature sensors require less calibration as they tend to maintain better accuracy levels. The humidity sensor will require more frequent calibration as accuracy can shift at higher temperature ranges. This is not a substantial problem if the product in question needs to be tested for relatively low temperature ranges but is the control process requires cycling over a large temperature range then a robust temperature-humidity sensors with frequent calibrations is recommended.

When purchasing new and used units it is also advisable to ensure that calibration certificates are provided with the purchase (Don't forget to ask if the certificates are traceable and for which regions they are valid). A calibration certificate should be a minimum requirement to conform for international standards. Various international validation requirements also regulate the way electronic signatures are used, how electronic data is stored and other computerized system requirement affecting Stability Testing. So not only must your temperature-humidity sensors be compliant but also any associated data storage units. Those interested in further reading would do well to reference the FDA 21 GMP's Eudralex volume 4 requirements.