Agitator Granulators

The machine classes to be considered under mechanical agitator granulators are (1) ribbon or paddle blender (2) planetary mixers (3) orbiting screw mixers and (4) sigma blade mixers. 

Paddles instead of ribbons decrease sticking problems and the torque required. Paddle blenders as batch granulators can handle wetter paste. These paddle blenders are occasionally used as continuous granulators and have both lower torque and more applications than a continuous ribbon blender. The movement of the paste helps remove material from the paddles. Formulation of a nontacky paste is aided by using a substance such as microcrystalline cellulose that helps absorb the excess moisture from the mix, yet is plastic and nonsticky. 

Two very popular ribbon or paddle blenders used as granulators are the topo-granulator and the turbulizer. 

The topogranulator is used extensively to make effervescent products by liquid addition under vacuum or by the Murry fusion method (6). Murry s method uses liberated moisture from the acid in the mix (i.e., hydrous citric acid) to start the acid-base reaction, which generates more water. Thus, granulating of the sodium bicarbonate-citric acid mixture can be accomplished. The water produced must be removed quickly to reproducibly stop the reaction. The topogranultor, because of its ability to compress the particles into the binding moisture, makes a larger, denser 

Granulation in vacuum removes entrapped air from the particle surface. Liquid addition into the vacuum provides immediate wetting and also begins the drying process. This granulation in vacuum allows the manufacturing of a calcium carbonate-based effervescence with rapid reactivity (7). 

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For successful tableting, a material must have suitable flow properties to allow it to be fed to the tableting machine. Wet or dry granulation is used to improve the flow properties of materials. In the case of wet granulation, agitative granulation techniques such as fluidized beds or mixer granulators as discussed above are often employed. 

Charge item 1, sucrose, D-mannitol, saccharin sodium, and disodium ethylenediamine tetraacetate in an agitating granulator. 

S. Watano, K. Terashita, K. Miyanami, Frequency analysis of power consumption in agitation granulation of powder materials with sparingly soluble acetaminophen, Chem. Pharm. Bull. 40 (1992) 269-271. 

Iveson, Litster JD, Hapgood KB, Ennis J. Nucleatiem, growth and breakage phenomena in agitated granulation process a review. Powder Tcchnol 2001 117 3-39. 

R. Oliver, Fluidized bed and other vigorously agitated granulators . Manuscript, Waterloo Intensive Course on Agglomeration Fundamentals, Waterloo, Ontario, Canada, 1985. 

Makino T, Kitamori N. Effect of starch paste concentration on particle size distribution of line granules produced by agitation granulation. Chem Pharm Bull 1995 43(7) 1231-1233. 

In contrast to monophosphates, starch phosphate diesters contain cross-links between two or more starch chains. This covalent linkage in the granule produces a starch product which swells less but is more resistant to heat, agitation, and acid than natural starch. 

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