Roller compaction

Extensive research has been conducted on the use of the following SWMs as highway C R materials (an alternative innovative way to recycle/reuse such wastes), soil stabilization material, roller compacted concrete, and road base stabilization materials. They include the following [1]. 

Within the pharmaceutical industry, granulation is a widely used process to prepare drug substance and excipient particles for compression. " There are wet and dry granulation procedures herein high shear wet grannlation, fluid bed granulation and roller compaction will be discussed. 

A. Gupta, G.E. Peck, R.W. Miller and K.R. Morris, Nondestructive measurements of the compact strength and the particle-size distribution after milling of roller compacted powders by near-infrared spectroscopy, J. Pharm. Sci., 93(4), 1047-1053 (2004). 

High-energy processes (milling, lyophilisation, granulating, drying) can introduce certain amounts of amorphicity into otherwise highly crystalline material [20]. As has been previously indicated, enhanced levels of amorphicity lead to increased local levels of moismre, and increased chemical reactivity in these areas. Hancock and Zografi [49] reported on the impact of a roller-compaction process on the water vapour sorption of a sample of aspirin. They speculated that... 

Murray M, Laohavichien A, Habib W, et al. Effect of process variables on roller-compacted ibuprofen tablets. Pharm Ind 1998 60 257-62. 

In the aforementioned chapter in the First Edition Reference 1,1 mentioned, There is no such thing as a standard approach to solve compactor scale-up or compactor equipment changes in the pharmaceutical production process (1). At that time of the publication, it appeared that was very much the case history of roller compaction scale-up in the pharmaceutical industry. This understanding was based on the fact that there were no pharmaceutical industrial journal articles published at the time on the subject. On the other hand, it was also true that considerations, approaches, and examples presented in that chapter were experienced by others and were not all-inclusive. 

The following roller compaction scale-up examples illustrate technology strategies that identify equipment design features, process parameters, and evaluations defining roller compaction scale-up processes. 

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. 

The roller compactor s full axial rolls produced compacts in the form of sticks. The unmilled compacts from both machines had the same density, 1.3g/cm. The milled roller compacts produced comparative granules except for bulk density and correspondingly the Carr index values ... 

The milled compacts generated slightly larger particles where the round slugs produced from the Carver press produced a greater number of fines. The compactor flow rate for the milled roller compacted material was twice as fast as that of the Carver press granules, but both flow rates were deemed acceptable. The authors concluded that both methods produced, for all practical purposes, equivalent granulated material. 

In the third country, roller compaction was substituted for the slugging process. While the sizing of the slugs and compacts were completed on different machines, and the particle size results were not exactly the same in each situation, the tablet content uniformity results were equivalent. Content uniformity relative standard deviations of 1.5-2.0% ( = 10 tablets) were routinely achieved. The tablet dissolution profiles averaged 95% or higher within 30 minutes in each country. 

Wet Granulation Technology vs. Slugging Technology vs. Roller Compaction Technology... 

Table 8 Powder Properties from Non-Roller Compacted Formulation and Powder Properties from Vector Freund Lab and Pilot Roller Compaction Processes...

Roller Compaction Scale-Up Using Near Infrared (NIR)... 

Figure 1 NIR blend monitoring of magnesium stearate in a roller compaction preblend and final blend.

In summary, it appears that roller compaction pre- and postblends can be NIR monitored during scale-up, independent of batch size and blender type. Using real time NIR monitoring would advance blender unit operations knowledge and provide continuous information and assurance about specific unit operations such as roller compaction, a key FDA Process Analytical Technology goal. 

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