Granules characteristics

Compounds based on polymers that are not themselves hygroscopic can sometimes cause problems because of hygroscopic additives. 

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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. 

Gore et al. (130) studied the factors affecting the fluid-bed process during scale-up. The authors found that processing factors that most affected granule characteristics were process air temperature, height of the spray nozzle from the bed, rate of binder addition and the degree of atomization of the binder liquid. 

As previously discussed, the appropriate process-air volume, inlet-air temperature, and binder spray rate are critical to achieving proper and consistent particle size distribution and granule characteristics. There are many ways to arrive at the proper operating parameters. The following procedure was found by the authors to be one of the ways one can set the operating parameters when granulating with fluid bed processors. 

Figure 11 shows the output of commercial granulated material versus its moisture content with agglomerating liquid No. 3 utilized in granulation. Characteristic curves are also typical of the other preparations of agglomerating liquid. 

Genovese, D. B. and Rao, M. A. 2003. Role of starch granule characteristics (volume fraction, rigidity, and fi tal dimension) on rheology of starch dispersions with and without amylose. Cereal Chem. 80 350-355. 

Kiekens, F. Cordoba-Diaz, M. Remon, J.P. Influence of chopper and mixer speeds and microwave power level during the high-shear granulation process on the final granule characteristics. Drug Dev. Ind. Pharm. 1999, 25 (12), 1289-1293. 

The primary function of tablet lubricants is to reduce the friction arising at the interface of tablet and die walls during compression and ejection. Lubricants also possess antiadherent (prevention of sticking to the punch and, to a lesser extent, to the die wall) and gli-dant (improvement of flow characteristics of powders or granulates) characteristics and are useful in the processing of hard gelatin capsules. 

Akay, G. Tong, L. Process intensification in polymer particle technology granulation mechanism and granule characteristics. J. Mater. Sci. 2003, 38, 3169-3181. 

Loo C-Y, Sudesh K (2007) Biosynthesis and native granule characteristics of poly(3-hydroxybu-tyrate-co-3-hydroxyvalerate) in Delftia acidovorans. Int J Biol Macromol 40 466-477 Lu H, Liu Y, Zhou H, Yang Y, Chen M, Liang B (2009) Production of biodiesel from Jatropha curcas L. oil. Comput Chem Eng 33 1091-1096... 

In general, the mixture discharged from the PCR does not require further reaction with ammonia in the granulator. In some cases, however, the level of reaction in the PCR may be altered (decreased) to minimize the escape of ammonia or to obtain improved granulation characteristics of the melt when it is combined with the solids in the granulator. 

According to the foregoing discussion, a large number of raw material and process variables must be considered when developing NPK production formulations that result in good granulation characteristics. As with the operation of an NPK granulation plant, formulation too, requires a considerable amount of skill and an element of art to ensure that the particular formulation will yield the desired results in a specific situation. 

Several factors control the granule characteristics. They include the particle size distribution of the initial powder, the degree of flocculation of the slurry, the type of additives, and the spray-drying conditions. The key granule characteristics are... 

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