Granule size distribution of tablets

The purpose of this study was to determine the variation in the granule size distribution in a die of an eccentric tableting machine. Theophylline anhydrate and α‐lactose monohydrate were granulated with an aqueous solution of polyvinylpyrrolidone, using an instrumented fluid bed granulator. The granules were tabletted, using an instrumented eccentric tableting machine. Punch forces were recorded and tablets were collected in order during the tableting process. Powder samples, which had the same mass as the tablets, were also collected from the die for particle size determination. The particle size distribution was measured, using a spatial filtering technique. In addition, the segregation of microcrystalline cellulose pellets during tableting was analyzed. The particle size distribution changed dramatically during the tableting process, due to a segregation phenomenon. © 2009 Wiley‐Liss, Inc. and the American Pharmacists Association J Pharm Sci 99: 2061-2069, 2010