Scale-up of agitation fluidized bed granulation. V. Effect of moisture content on scale-up characteristics

Abstract

Characteristics of granulation scale-up with moisture variation were investigated using an agitation fluidized bed of four sizes (vessel diameter 125, 230, 500 and 750 mm). Agitation fluidized bed granulation was done under various levels of moisture content and the vessel sizes. Granule properties of mass median diameter, geometric standard deviation, apparent density, shape factor and friability were investigated to know the effect of moisture content on the scale-up characteristics. It was found that a linear relationship between granule mass median diameter and moisture content was observed regardless of the vessel size, however, the mass median diameter decreased as this size. The geometric standard deviation decreased with increase in moisture content, showing that granule size distribution was narrowed as granule growth progressed; the deviation increased, however, with increase in vessel size. The apparent density and shape factor tended to increase with moisture content and vessel size. It was concluded that these phenomena could be explained by the adhesion and separation force experienced by the granules during granulation. Also, the scale-up characteristics could be well explained by the moisture content.