Occurrence of fragmentation during compression of pellets prepared from a 4 to 1 mixture of dicalcium phosphate dihydrate and microcrystalline cellulose

The occurrence of pellet fragmentation during the compression of pellets pr epared mainly from a hard pharmaceutical filler material was investigated. The pellets consisted of 4 parts dicalcium phosphate dihydrate (generally c onsidered as a hard material) to 1 part microcrystalline cellulose (used as a pellet forming material). Pellets of two porosities, 36% and 55%, were p repared. Compacts formed at 100 MPa applied pressure were fractured and the fracture surfaces were then visually examined. Lubricated pellets were als o compacted in order to obtain tablets which could be easily deaggregated. Pellets retrieved from deaggregated tablets were compared with uncompacted pellets with respect to size and fracture resistance. The results showed th at many pellets exposed in the tablet fracture surface were fractured, espe cially those with higher porosity. However, the lubricated pellets retrieve d from deaggregated tablets were similar in size to the uncompacted pellets , i.e. fragmentation of these pellets was minimal. Furthermore, these retri eved pellets were more resistant to fracture than the original uncompacted pellets, indicating that the formation of cracks or flaws in the pellets du ring compaction was also minimal. It was thus concluded that deformation an d probably densification; and not fragmentation, was the dominant compressi on mechanisms of this pellet formulation. (C) 1999 Elsevier Science B.V. Al l rights reserved.