SPHERONIZATION CONDITIONS ON SPHEROID SHAPE AND SIZE

The effects of spheronization speed and residence time on the size and sphericity of microcrystalline cellulose (MCC)-lactose spheroids were investigated. Generally, spheroids became larger and more spherical w ith an increase in the residence time and spheronization speed. With v ery high speeds or long residence times, small spheroids resulted. It was found that a combination of speeds ranging from 1000 to 2000 rpm a nd residence times between 5 and 15 min may be used to produce spheroi ds with a modal fraction in a size range of 0.7-1.0 mm. The effects of varying MCC content and amount of water required for spheronization w ere also studied. The addition of a larger amount of water produced sp heroids with larger mass median diameters. A higher proportion of MCC required correspondingly a greater amount of water to form spheroids o f a certain mean size. An equation could be used to predict the quanti ty of water needed to produce spheroids of a required size range. Vari ation in the particle size of the lactose used also affected the size of spheroids formed. The coarser lactose grade produced larger spheroi ds. Granule size distribution and sphericity were found to be dependen t on the operating conditions. Therefore, with a particular formulatio n, the variable parameters must be suitably adjusted to complement eac h other for successful spheronization.