The effect of raw material and atomizing air pressure on the properties of granules prepared in a fluidized bed granulator

Granules were prepared in a fluidized bed granulator using three excipients, lactose monohydrate, anhydrous glucose and mannitol, along with two atomizing air pressures. Other process parameters were kept constant during granulation. The binder solution used was a 20% (w/w) polyvinylpyrrolidone (Kollidon K25) solution in water. The lactose granules were spherical and their moisture content was low. A high moisture content, resulting from the hygroscopicity and the hydrate formation during granulated,was typical for glucose granules Mannitol granulated poorly, and the granules formed were large and spherical. Of the granules studied, mannitol granules were the most friable ones. The atomizing air pressure used was found to affect the granule size. The pressure affected the moisture content of only the final hygroscopic glucose granules. Granules prepared with the higher atomizing air pressure were usually more friable. The Pearson analysis showed a negative correlation between flow time and atomizing air pressure with glucose granules. With lactose, no correlation was found and with mannitol the test could not be performed because some batches did not flow at all.