Influence of process variables on granulation of microcrystalline cellulose in vibrofluidized bed

Wet granulation of microcrystalline cellulose (MCC) has the objective of minimizing particle losses caused by elutriation in compression and coating processes. The MCC physical properties suggest the conventional fluidized bed as adequate for the granulation process; however, literature reports the occurrence of poor fluidization dynamic (preferential channels and dead zones) during this particle fluidization. This work reports the granulation of MCC in vibrofluidized bed, using aqueous solution of maltodextrin (35%) as binder. A fractional experimental design (2(5-1)) was developed to assess the influence of process variables: amplitude and frequency of vibration, atomization pressure, inlet air temperature, and granulating solution flow rate on the responses: particle growth, angle of repose, lump index and mass of elutriated particles. The results showed an increase of the Sauter mean diameter related to the original value from 3.17 to 33.11%, confirming the granulation of the material. The granules obtained revealed good flowability and low lumps index. The levels of independent variables that resulted in a higher reduction of elutriation were the same ones that provided the highest growth of the particles. (C) 2010 Elsevier B.V. All rights reserved.