The Relequa sample moisture test has been used to investigate a problem involving inconsistencies in the stability of batches of a film-coated tablet.
The film-coated tablet is packed in blisters and was showing an increase in hydrolysis products over the initial months under all conditions of stability testing.
More batches of the same product packed in the same way were placed on stability.
This time, very little hydrolysis was seen and these batches were still well within specification after two years.
Using Relequa, batches were analysed from routine manufacture, stability batches and retained samples from the first manufacturing runs.
The investigation found that, even after prolonged storage, the retained samples still contained residual moisture and had an equilibrium relative humidity (ERH) of more than 60 per cent.
All the other batches had an ERH in the range 50-55 per cent.
This provided an explanation for the higher level of hydrolysis in the first development batches: within each blister pocket, a high-humidity chamber was created as each tablet released 'free moisture'.
The problem was there at the beginning and was eventually traced to poor efficiency in the drying step during film coating.
This investigation demonstrated that, by applying the sensitive Relequa sample moisture test, valuable information can gained about the free-moisture status of a product, resulting in cost savings.
