Effect of particle size of active ingredient on physicochemical properties of water dispersible granules obtained through direct granulation of agrochemical suspension using fluidized bed

Direct granulation of agrochemical suspension containing a solid active ingredient (AI) with different particle sizes was carried out to prepare water dispersible granule (WDG) using fluidized bed. The effect of the particle size of AI on granule mass median diameter and disintegration time was investigated experimentally. The granule median diameter tended to increase with an increase in particle size though different tendency was observed when the particle size was equal or greater than that of the spray mist size. The disintegration time increased with a decrease in particle size. It was concluded that these phenomena can be explained by the amount of a free binder which is not adsorbed on AI particle surface.