A study on bottom-spray granulation and its potential applications

Abstract

The potential of bottom-spray fluidized bed granulation has not been fully realized with limited research in this area. This gap in scientific knowledge and the improved, modified Wurster system introduced recently, precision granulation, provided the much needed impetus for this study. It was hypothesized in this study that highly ordered particle circulation pattern and unique fluid dynamics of the bottom-spray process was advantageous for (i) the spray deposition of a micronized drug during granulation and (ii) wet granulation of moisture sensitive drugs. Parameters affecting bottom-spray granule formation were investigated. Mode of granule growth, process sensitivities, granule compaction behaviour and potential for use in the applications of interest were comparatively studied with the conventional top-spray process. Having not only comparable granule and tabletting properties as conventional top-spray granules, the more spherical bottom-spray granules also had better drug content uniformity and reduced degradation of moisture sensitive drug. The findings in this study were encouraging for they highlighted the suitability of the bottom-spray process for the spray deposition of a micronized drug during granulation. Additionally, the bottom-spray process represented a unique technique amenable to the application of wet granulation of moisture sensitive drugs.