Mean Kinetic Temperature (MKT)
Measurement and recording of temperatures is vital to the storage of perishable goods, but there is more than one way to record an average.
The ICH defines the mean kinetic temperature as being “a single derived temperature that, if maintained over a defined period of time, affords the same thermal challenge to a drug substance or drug product as would be experienced over a range of both higher and lower temperatures for an equivalent defined period”.
MKT expresses the cumulative thermal stress experienced by a product at varying temperatures, during storage and distribution. It differs from other means (such as a simple numerical average or arithmetic mean) in that higher temperatures are given greater weight in computing the average, thus, recognizing the accelerated rate of thermal degradation of materials at higher temperatures.
The mean kinetic temperature is calculated as being:
Tk being the mean kinetic temperature in Kelvin
ÄH is the heat activation in kJoule per mole
R is the universal gas constant in kJoule per mole per Kelvin
T1 and Tn are the temperature samples for periods 1 and n, respectively
n is the total number of periods in the calculation
There are a number of interpretations of how this calculation is achieved using real samples:
- All sample values fed into formula
- Maximum/minimum samples fed into formula separately (recommended by the FDA)
- Arithmetic mean of maximum and minimum fed into formula (recommended in the US Pharmacopeia and by the UK MCA)
Eurotherm offers all the above methods with:
- A choice of stability testing period (hourly / daily / weekly)
- A choice of sampling frequency (from 1 minute to 1 hour)
- Option to remove individual probes from calculation (e.g. during a calibration process)
- Corrective action in case stability is out of specification
- Secure and low cost custom reporting
- Significant reduction of the cost of ownership
