MKT
WHAT IS MEAN KINETIC TEMPERATURE?
Mean Kinetic Temperature (MKT) is a simplified way of expressing the overall effect of temperature fluctuations during storage or transit of perishable goods.
Consider the following example :
A dozen eggs sat: In a 20º C room for 2 hours , In 2º C refrigeration for 4 hours , And on a 25º C loading dock for 1 hour , Using MKT we can calculate that temperature profile of the eggs was "thermally equivalent" to storing them at 15.7º C for 7 hours.
Time | Temperature |
13:30:00 to 14:30:00 = 1 hour | 20 º C |
14:30:00 to 15:30:00 = 1 hour |
20 º C |
15:30:00 to 16:30:00 = 1 hour | 02 º C |
16:30:00 to 17:30:00 = 1 hour | 02 º C |
17:30:00 to 18:30:00 = 1 hour | 02 º C |
18:30:00 to 19:30:00 = 1 hour | 02 º C |
19:30:00 to 20:30:00 = 1 hour | 25 º C |
Equivalent of storing for 7 hours @ 15.67 º C | MKT=15.67 º C |
HOW IS MEAN KINETIC TEMPERATURE CALCULATED?
Technically speaking, MKT is an expression of cumulative thermal stress experienced by a product at varying temperatures during storage and distribution. In other words, MKT is a calculated, single temperature that is analogous to the effects of temperature variations over a period of time.
MKT is not a simple weighted average. The calculation of MKT gives the higher temperatures a greater weight when computing the average than would a simple numerical average or an arithmetic mean. This weighting is determined by a geometric transformation--the natural logarithm of the absolute temperature.
The International Conference on Harmonization (ICH) stability testing guidelines define MKT as "a single derived temperature, which, if maintained over a defined period, would afford the same thermal challenge to a pharmaceutical product as would have been experienced over a range of both higher and lower temperatures for an equivalent defined period".
By using this unequal weighting of the higher temperatures in a temperature series, MKT takes into consideration the accelerated rate of thermal degradation of materials at these higher temperatures. Therefore, MKT provides for the non-linear effect of temperature.
ΔH = the heat of activation for the degradation reaction; assumed to be 83.144 kJ per mol (see discussion below) unless more accurate information is available from experimental studies. R = 8.3144 × 10^{-3 }kJ per degree per mol (the universal gas constant) T1 = the average temperature, in degrees Kelvin, during the first time period T2 = the average temperature, in degrees Kelvin, during the second time period Tn = the average temperature, in degrees Kelvin during the nth time period n = the total number of temperatures recorded. Note that the interval between temperature measurements is assumed to be identical. |
WHY IS MKT IMPORTANT IN THE LIFE OF PHARMACEUTICALS AND PERISHABLE GOODS?
The pharmaceutical and food industries are two closely regulated markets. The FDA provides regulations that require warehouse and shipment temperatures to be closely controlled and monitored. In addition, the FDA requires well-documented verification of these storage environments and any corrective actions taken if temperatures exceed specified storage conditions.
The calculation of MKT is regarded by the FDA as an action taken to verify if a particular perishable has exceeded storage conditions.
In addition to compliance with the FDA regulations, MKT can help Distributors and Manufacturers determine if improper storage or handling of goods, that might have occurred during shipment and/or unloading, has affected the shelf life of the their product.