EFFECT OF PROCESS VARIABLES ON THE PROPERTIES AND BINDER DISTRIBUTIONOF GRANULES PREPARED IN A FLUIDIZED-BED

A lactose-cornstarch model system with hydroxypropyl methylcellulose 2 910 (HPMC 3cP) as a binder was used to evaluate the effects of several process variables (moisture level, spray feed rate and drying air flo w rate) on the particle size distribution of granules prepared in a fl uidized bed using a dry mixing method of binder addition, Moisture lev els were controlled via an infrared moisture sensor, The distribution of binder in different sized fractions of granules was also determined by measuring the contents of the methoxyl group, Moisture level was t he most important factor for granule growth, and higher moisture level s increased the granule size, The time for which a given moisture leve l was maintained and the fluidizing air how rate had little effect on granule size, size distribution, binder distribution or apparent densi ty, This implies that mixing is efficient during fluidized bed granula tion by the dry mixing method and that binder behavior is mainly deter mined by the moisture Level of the wet mass, It was concluded that if a fixed moisture level is maintained during fluidized bed granulation with the dry mixing method of binder addition, variation of the other operational conditions should have little effect on the consistency of the product.