Effects of process variables on the size, shape, and surface characteristics of microcrystalline cellulose beads prepared in a centrifugal granulator

Preparation of microcrystalline cellulose (MCC) beads with a laboratory-sca le centrifugal granulating apparatus was studied, and the pharmaceutical qu ality of the beads was characterized with respect to the,subsequent drug la yering. Five process parameters of potential importance, including rotor ro tation speed X-1, slit air X-2, spray air pressure X-3, spray air rate X-4, and height of nozzle setting X-5, were evaluated using a fractional factor ial design (FFD 2(5-2)) as the experimental design. The responses evaluated were expected yield, mean size, size distribution, shape characteristics ( including roundness, circularity elongation, rectangularity and modelx), an d friability. All five process parameters studied were found to have an inf luence on the selected properties of the beads, but the effects of rotor ro tation speed, slit airflow rate, and spray air rate were statistically sign ificant (p <.05). The effect of the rotor rotation speed was found to be th e most potent on all the responses studied. The results also show some sign ificant interactions between the parameters tested. The most significant in teractions were between rotor rotation speed and slit air, rotor rotation s peed and spray air, and slit air and spray air.