Effect of the formulation parameters on the characteristics of pellets.

Pelletization is increasingly applied currently for the preparation of solid oral controlled-release dosage forms. The production of the particles, which are regular in shape and size, can be achieved with the application of the proper polymer auxiliary materials and new pharmaceutical technological methods (extrusion, spheronization). Regularity in shape and size, attained by the optimization of several production parameters, can promote the coating procedure. Under optimal conditions, particles were prepared for coating in a high-shear mixer, which is used to produce uniform particles. The effect of the rotating speed of the applied chopper and the amount of microcrystalline cellulose in the composition on the physical characteristics of the pellets was modeled by a second-order polynomial equation fitted to the data gathered by a face-centered central composite statistical design.