Temperature

Temperature control in tablet dissolution testing is critical as a change in temperature has a linear effect on the dissolution rate. Temperature should be measured with a calibrated thermometer, either analogue or digital, and should normally be 37°C.

The specified temperature should be measure in each vessel prior to each run commencing. There is a temptation to only measure temperature in a few of the vessels and assume that they are all the same. This may not necessarily be the case as temperature gradients can occur within a water bath that effect the speed of equilibration of all the vessels.

Most dissolution baths display the temperature of the bath itself but this should not be taken as an indication of the temperature inside the vessel. Typically it is necessary to run the water bath 0.5°C or so above the required temperature to ensure the correct temperature inside the vessel. If plastic vessels are used instead of glass then this may be a greater difference.