Micro scale prediction of the roller compaction process

Roller compaction is the densification of dry powders into a solid mass (compact). This densification process is achieved by controlled feeding of powder through a set of directly opposed, counter-rotating rollers with a controllable aperture (roller gap) between the rollers. The feed powder is passed through the rolls with the flow being induced by the friction acting at the surfaces of the rolls. In the narrow region of the gap between the rolls, the powder is subjected to high pressure, leading to the formation of a compact or briquette that is reduced in size by milling or screening to achieve the desired granule size. Roller compaction is designed to increase the bulk density and uniformity of particulate formulations, for example, to prevent the segregation of pharmaceutical drugs. It offers advantages compared with wet granulation for processing physically or chemically moisture-sensitive materials since the use of a liquid binder is not required. Another advantage is that it does not require a drying stage and therefore it is suitable for compounds that either have a low melting point or degrade rapidly upon heating [2,3,4,5].