Influence of load on particle size distribution of lactose-crystalline cellulose mixed powder.

Effects of loads applied to a powdery layer of a mixture of lactose and crystalline cellulose (granules) on the microparticle formation were evaluated. In a 1:1 mixture, the number of particles size, 20 microm or smaller in diameter, was reduced under loading compared with the standard value. It tended to increase with increasing ratio of lactose. In samples with a particle size of 350 microm or less, the shear friction coefficient increased with increase in the load, reached a peak at a mixing ratio of 50%, and decreased with increase in the mixing ratio. These changes were similar to those of the number of particles 20 microm or smaller. These results suggest that particle formation and aggregation under loads are dependent on the mixing rate and that there is a range of mixing rates in which no changes in the particle size distribution are observed.