Feasibility of Eliminating Premixing for the Production of Pellets in a Rotary Processor

Abstract

This current study aims to explore the feasibility of eliminating the premixing step for making pellets in a rotary processor. Microcrystalline cellulose (MCC) and lactose were used as starting materials. They could be loaded into the rotary processor separately using three different loading configurations (Methods I, II, and III) or as MCC:lactose blend, which was prepared in the separate mixer prior to loading (Method IV). Physical properties of the pellets prepared in Methods I–III were evaluated and compared against those prepared using a premixed blend (Method IV). The effects of loading configuration on pellet quality can be assessed by comparing the pellets prepared in Methods I, II, and III. Physical characterization of pellets included mean size, size distribution, oversized fraction, and shape. No significant difference in pellet properties could be attributed to the effect of premixing. Pellet properties were not significantly affected by the different loading configurations either. This study demonstrated that homogeneous powder blends are not required for the production of pellets in rotary processing. The tumbling action of the powders at the start of rotary processing is sufficient to ensure adequate powder mixing. However, it may be judicious to co-feed the different powders to achieve some preliminary mixing during loading under extreme processing conditions.

Keywords:

• premixing
• rotary processor
• loading configurations
• microcrystalline cellulose
• pelletization