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 with an increase in the residence time and Spheronization speed. With very high speeds or long residence times, small spheroids resulted. It was found that a combination of speeds ranging from 1000 to 2000 rpm and residence times between 5 and 15 min may be used to produce spheroids 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 were also studied. The addition of a larger amount of water produced spheroids with larger mass median diameters. A higher proportion of MCC required correspondingly a greater amount of water to form spheroids of a certain mean size. An equation could be used to predict the quantity of water needed to produce spheroids of a required size range. Variation in the particle size of the lactose used also affected the size of spheroids formed. The coarser lactose grade produced larger spheroids. Granule size distribution and sphericity were found to be dependent on the operating conditions. Therefore, with a particular formulation, the variable parameters must be suitably adjusted to complement each other for successful Spheronization.