Evaluation of different types of starch used as binder in fluid bed granulation process.

In recent years, pregelatinized (partially or fully) starches have been proposed as alternative to starch paste as binder in wet granulation; however litte attention has been paid to their utilization in fluid bed granulators. The main aim of this study was to investigate the possibility to substitute conventional starch paste with pregelatinized starch as binder in fluid bed granulation process. Moreover, the effect of some formulation parameters such as the kind of starch (partially or fully pregelatinized) and the form in which it is added (powder form or cold suspension) on the characteristics of the obtained granules (particle size distribution, bulk and tapped density, flowability and residual moisture) and tablets (hardness, friability and disintegration time) has been evaluated. The results show that conventional starch paste can advantageously be substituted by some kinds of modified starch in the fluid bed granulation. In particular Starch 1500 can be employed in dry powder form or in cold suspension; both the forms allow to manufacture granules with good flowability and tablets with good hardness and friability, besides a very short disintegration time, without adding other disintegrants. Futher studies are in progress to correlate the different behaviour of the partially pregelatinized starches employed in this work with their morphology and physico-chemical properties.