CONSOLIDATION AND COMPACTION OF POWDER MIXTURES .3. BINARY-MIXTURES OF DIFFERENT PARTICLE-SIZE FRACTIONS OF DIFFERENT TYPES OF CRYSTALLINE LACTOSE

Tablets were compacted from a coarse fraction (250-315 mum), a fine fraction (32-45 mum) and from binary blends of a coarse and a fine fraction of different types of crystalline lactose. The results showed differences in consolidation and compaction between the granular lactose types, i.e., roller-dried beta-lactose and anhydrous alpha-lactose, and the non-granular lactose types, namely, crystalline beta-lactose and alpha-lactose monohydrate. Equal particle size fractions of the granular types of lactose exhibited greater specific powder surface areas, less fragmentation on compression, and higher binding capacities than the non-granular types. Slight increases in consolidation were demonstrated on compression of binary blends of the coarse and fine fraction of the different types of lactose. Differences in morphology between the lactose types were shown by increasing true densities of the granular types when examined on tablets compacted with increasing compression force. No change in true densities on compaction were demonstrated by the non-granular types.