During investigation of tablets placed on stability, one company found that the tablets' moisture-related problem could not be rectified using conventional testing.
Using a Relequa system, the company compared the stability batches with newly manufactured batches.
Its investigation found that the stability batches had an Equilibrium Relative Humidity (ERH) close to the chamber humidity condition.
The newly manufactured batches had a 20 per cent lower ERH.
The increased ERH demonstrates that the stability batches had picked up moisture.
The approach was derived from the company's experience of tablets that were shown to have trapped moisture in the matrix.
This was elucidated over several weeks of exposing the tablets directly to different levels of humidity.
This time, using the highly sensitive Relequa test on the stability batches, the company generated moisture profiles of whole tablets, along with tablets that were sliced in half lengthways.
It used the dual chambers of the Relequa unit to obtain an instant, direct comparison.
Immediately, the split tablets were seen to be releasing moisture much faster than the whole tablets.
This trapped moisture is instantly lost when tablets are powdered for testing, can affect sample weight in assays and goes undetected in water-content measurements.
The instantaneous comparative result, obtained using the Relequa ERH system, saved time and costs.
