Influence of process variables on physical properties of the pellets using extruder and spheronizer.

Placebo pellets containing lactose and microcrystalline cellulose (Avicel PH101) ratio 60:40 were prepared by the extrusion-spheronization process. The influence of processing variables, including the spheronizer speed, the spheronization time, the binder type, and the concentration and amount of water content on physical properties of the pellets, were studied. The sphericity of pellets was increased with increasing spheronizer speed during wet mass process. When spheronization time was increased, sphericity, smooth surface, and particle size of pellets were increased. Increasing binder concentration will increase particle size. Pellets using HPC-M as a binder at high spheronizer speeds showed spherical shape, narrow size distribution, and good flow properties when compared with Methocel E-15LV, HPC-L, and Methocel A4M. In addition, increasing HPC-M concentration had no effect on shape and particle size of pellets. The amount of water content was found to affect shape, flow rate, and density. In summary, suitable conditions consisted of 2% w/w of HPC-M, 40% w/w of water, and 15 min of spheronization time at 951 rpm of spheronizer speed.