The role of particle size distribution on compaction and tensile strength of pharmaceutical powders

The effect of particle size distribution on compaction of powders and tensile strength of the compacted powders was investigated for microcrystalline cellulose and lactose monohydrate powders. Several samples were prepared by removing portion of the fine particles from the initial particle size distribution of the powders. The powders were compacted to form tablets and the tensile strength of the tablets was measured. Removing the fine particles showed no effect on the compaction force and tensile strength of the two powders. However, smaller initial relative density was observed for powders with larger particle size. Although the different samples initially had different relative density, the relative density approached the same value for the different samples as the compaction force was increased. These results indicate that the particle size distribution affects the flow of powders but not the mechanical properties of tablets