Roller compactor sizing compacts

Gereg and Capolla developed process parameters determined by a model laboratory bench scale Carver press, model C (Carver Inc. Savannah, Georgia, U.S.A.), which were translated to production scale compactor parameters (6). Their study provided a method to predict whether a material is suitable for roller compaction. Their study objectives were to characterize properties of the material to identify process parameters suitable to achieve the necessary particle size and density using the dry granulation process and then translate laboratory information to a production scale roller compactor. Actually, information developed from a Carver press was correlated and scaled-up to a production scale Fitzpatrick roller compactor. Model IR 520 (Fitzpatrick Co., Elmhurst, Illinois, U.S.A.) The compactor produced very similar powder granule characteristics as the Carver press. Various lactose materials, available as lactose monohydrate or spray dried lactose monohydrate, were used as the model compounds. Results indicated that a parametric correlation could be made between the laboratory bench Carver press and the production scale compactor, and that many process parameters can be transferred directly. 

Figure 5 shows the results of the authors study on the ability of NIR to monitor the scale-up from the laboratory Carver Press to the Fitzpatrick roller compactor. Because the NIR signal is influenced by changes in the physical and mechanical properties, multivariate data analysis techniques were used to identify and separate these contributions in the overall NIR signal. A flat-faced rectangular die and punch set, 40 x 15 mm in size, was fitted on the laboratory Carver Press to prepare tablets similar in shape and size to the roller compacted samples. 

Sizing devices are now trimly fitted to the compactor body and controlled by variable speed drives. Most compactors no longer require a second machine (mill) in tandem to size compacts as required by slugging technology. Roller compactors have clean-in-place (CIP) systems that offer environmental and safety features. These systems minimize human exposure to chemicals and improve cleaning efficiencies. Fig. 7. 

Roller compactors are available in different designs and can be equipped with a variety of differently profiled rollers to produce compacted material, pellets, or briquettes. Usually, the compacted product then has to be milled to the desired particle size. To minimize dust and fines, which have to be recycled back to the compaction process, selection of suitable milling equipment is important. Gentle systems, such as roller mills or sieve mills, are preferred. As Figure 16.21 shows, compacted granules appear as more irregular, sharp-edged particles. 

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