Roller compaction evaluation

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. 

Different spectral preprocessing and transformations available in SIMCA P-p (version 10.0, Umetrics, Sweden) were evaluated and the best approach for data handling and manipulation was determined. Data collected on the surrogate tablets were divided into a training set to generate the PLS models, and prediction set to test the PLS models. MCC powder, equilibrated at different RH, was also roller compacted at different roll speeds on a Fitzpatrick IR220 roller compactor fitted with smooth rolls. Powder feed rate and roll pressure were kept constant for all experiments. The key sample attributes measured on the surrogate tablets were also measured for the samples prepared by roller compaction. 

Skinner GW, Harcnm W W, Barnum PE, Guo JH. The evaluation of fine-particle hydroxypropylcellulose as a roller compaction binder in pharmaceutical applications. Drug Dev In Pharm 1999 25(10) 1121-1128. 

Sheskey PJ, Dasbach TP. Evaluation of various polymers as dry binders in the preparation of an immediate-release tablet formulation by roller compaction. Pharm Tcchnol 1995 19 98-112. 

Fluorogypsum is not being used in any commercial applications however, it has been evaluated for use as a road base material, and in the production of impure plasterboard Phosphogypsum is a calcium sulfate hydrate that is pumped into ponds, eventually dewatered, and ultimately disposed of in large stockpiles called stacks. It has been recovered and reused with some success in stabilized road bases, unbound road bases, and roller-compacted concrete. It can be used for agricultural purposes, if the radium-226 concentration of the source material is less than 10 pCi/g... 

A car park at the Lowdham Grange prison construction site in Nottingham was selected to evaluate the use of roller-compacted concrete (RCC) as the sub-base layer using Coventiy Binder. 

A number of these attributes, best technology practices, and features were rated for their industrial and pharmaceutical importance and reported by Miller and Sheskey in 2001 (33). Survey findings evaluated future industry usage of roller compaction technology in technical operations and in research and development (Fig. 8). 

Golchert, D., Bines, E., Carmody, A. (2013). Evaluation of some compression aids in tableting of roller compacted swellable core drug layer, Int J. Pharm., 453,322-328. 

The test paving constructions in two places mentioned below were carried out to evaluate the constructability and performance of the asphalt mixture with plastics. In both places, the surfaces of constructed pavement were enough flat, but less lustrous them the normal asphalt pavement. A comment of the constructors was that rakers felt a little heavier and the surface was hair-crackable at compaction by a roller. 

Samples of punch-and-die pressing can be produced in a variety of home made or purchased small machines. The previously mentioned force/pressure test stands (Fig. 11.18), which may also use hydraulic actuation with hand or motor pumps, can be applied in connection with home made punch-and-die arrangements. Many laboratories are equipped with automatically or hand operated hydraulic laboratory presses, for example as shown in Fig. 11.20 (see also Fig. 8.92, Section 8.4.3). From the suppliers of such machines a large number of simple or sometimes highly sophisticated and automated presses are available. They are used for the determination of a variety of strength and force or pressure related product characteristics and, although the densification and compaction mechanisms are quite different from those of roller presses and can not be correlated, punch-and-die compacts are often made and evaluated to preliminarily investigate the compactibility of different feed materials or powder mixtures and to determine the type and amount of potential binders. 

Another modular system is often called laboratory equipment it can be used for small scale production and for the laboratory evaluation of small samples. Fig. 11.26 depicts the design and some of the accessories. In the most simple execution a hopper feeds a pair of rollers which are driven by a hand crank. The rollers can be solid and may be equipped with compacting or briquetting surfaces (see Section 8.4.3) or two perforated, geared, intermeshing pelleting rolls (see Section 8.4.2) are installed to accomplish medium pressure extrusion. In a modular fashion the rollers can be motorized, screw feeders can be added, and the rolls may be oriented vertical or horizontal or in any other direction. As shown in the photographs of Fig. 11.27 the roller frame can be totally enclosed for dust control if toxic or hazardous materials are processed. A panel includes controls and instrumentation for data display and collection. 

As mentioned above, the compactibility of a particulate solid, the development of strength, and the potential need for modifications of the feed (e.g., particle size and distribution, composition, temperature, binder) can be evaluated with a laboratory punch-and-die press. However, this result only provides an answer to the question whether or not a material can be compacted and under which conditions. The pressure used during such an experiment, for example, can in no way be converted to the force that a roller press will have to exert for achieving the same good quality compacts. 

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