Effects of process variables on the size, shape, and surface characteristics of microcrystalline cellulose beads...

Preparation of microcrystalline cellulose (MCC) beads with a laboratory-scale centrifugal granulating apparatus was studied, and the pharmaceutical quality of the beads was characterized with respect to the subsequent drug layering. Five process parameters of potential importance, including rotor rotation speed X1, slit air X2, spray air pressure X3, spray air rate X4, and height of nozzle setting X5, were evaluated using a fractional factorial 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), and friability. All five process parameters studied were found to have an influence on the selected properties of the beads, but the effects of rotor rotation speed, slit air flow rate, and spray air rate were statistically significant (p < .05). The effect of the rotor rotation speed was found to be the most potent on all the responses studied. The results also show some significant interactions between the parameters tested. The most significant interactions were between rotor rotation speed and slit air, rotor rotation speed and spray air, and slit air and spray air.