The characterization of wet powder masses suitable for extrusion/spheronization.

The characterization of the flow of wet powder masses has been achieved using a ram extruder. Force/displacement curves obtained when material is forced through dies of varying length were found to exhibit three stages: (1) compression (2) steady state flow and (3) forced flow. To provide high quality extrudate it was found preferable to ensure that the compression stage was as short as possible and that steady state flow predominated. To produce these conditions, an optimum composition, die length and ram speed were required. The implications of these findings in relation to the provision of suitable formulations and production conditions for the preparation of spherical granules are discussed.