Abstract
Several kinds of theophylline granules were prepared in a high speed mixer by varying the kneading time, and their compression processes were analyzed by Heckel and by Cooper and Eaton equations. The compressibility of those granules was also examined comparatively by analyzing the compression energy applied to the powder layer to determine the relation between the compression behavior, compression energy, tablet hardness and internal structure of the tablet.The granules having the largest pore volumes were found to have high tablet hardness and tended to show larger ratios of compression loss energy to compression energy. It was suggested that in the granules having the largest pore volumes, the pores were easily filled by particle movement, rearrangement, plastic deformation and brittle fracture upon compression and the energy applied to the powder layer upon tableting was consumed efficiently.
