Multiple compaction of microcrystalline cellulose in a roller compactor

The effect of multiple roller compaction was investigated using microcrystalline cellulose as a model substance. Granules were prepared, examined and recompacted in a Gerteis 3 W-Polygran roller compactor up to ten times. Examinations were carried out for granule size distribution, density and flow properties. Ribbons were investigated for quality, and adhesion of ribbons to the rolls was traced. Finally tablets were produced from the granule samples and examined for their compression behaviour. Multicompression reduces the amount of fines, increases mean granule size and flow properties and also improves size distribution. Although roll adhesion diminishes with increasing cycles, this decrease is not sufficient enough to result in a visibly reduced gap variability. By multicompaction, bulk density increases which indicates that the porosity of granules decreased during the multiple compaction cycles. However, the ability of MCC to form bondings with neighbouring particles is diminished during various cycles which results in decreasing crushing forces of the subsequently prepared tablets.