Colloidal Silicon Dioxide specifications

Colloidal silicon dioxide is widely used in pharmaceuticals, cosmetics, and food products see Table I. Its small particle size and large specific surface area give it desirable flow characteristics that are exploited to improve the flow properties of dry powders in a number of processes such as tableting. " ... 

Table II Pharmacopeial specifications for colloidal silicon dioxide.

Several grades of colloidal silicon dioxide are commercially available, which are produced by modifying the manufacturing process. The modifications do not affect the silica content, specific gravity, refractive index, color, or amorphous form. However, particle size, surface areas, and densities are affected. The physical properties of three commercially available colloidal silicon dioxides, Aerosil (Degussa), Cab-O-Sil (Cabot Corporation), and Wacker HDK (Wacker-Chemie GmbH) are shown in Tables III, IV and V, respectively. 

The PhEur 2005 also contains a specification for hydrated colloidal silicone dioxide. The incidence of microbial contamination of colloidal silicon dioxide is low. 

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