(120a) The Effect of Binder Ratio on Granule Strength, Dissolution and Structure

Work on a system using calcium carbonate powder and
polyethylene glycol binders in high shear granulation has shown that in general
a trade-off line exists between the compression strength of granules and their
dissolution rate. 

Here the effect of increasing the binder-to-solids ratio
of the initial granulation mixture is studied and analysed for its effect on
granule strength, dissolution rate, composition and structure.  The system was
found to be very sensitive to changes in the binder-to-solids ratio, with
distinct differences observed between batches containing 10 and 16% overall
binder content.  The differences observed also had a direct influence on the
nature of single granule compression failure and also the dissolution and
particularly the binder content of the granules, which was found to have the
opposite trend to the binder ratio as added to the batch. 

Analysis of internal granule structure has also been
possible using x-ray tomography, which allows the powder and binder
distribution to be visually seen inside the granules.  Again there are distinct
differences to be seen between batches made with different binder ratios.