Densification of powders by concavo-convex roller compactor.

By means of a concavo-convex roller compactor, several pharmaceutical powders were compressed into sheets or flakes, which then were reduced in size by an oscillating granulator to form compacted granules. Several properties (bulk density, drop density, repose angle, and flow rate) of the powders and compacted granules were determined and compared. The primary effect of the roller compactor was to increase the bulk density without a significant change in flowability. Two materials compacted at five pressures demonstrated that the bulk and drop density are linearly related to the logarithm of compaction pressure.