Colloidal silicon dioxide is extensively utilized in pharmaceuticals, cosmetics, and food products. Its tiny particle size and large specific surface area provide excellent flow characteristics, which are beneficial for enhancing the flow properties of dry powders in various processes like tableting and capsule filling.

Colloidal silicon dioxide is also employed to stabilize emulsions and acts as a thixotropic thickening and suspending agent in gels and semisolid preparations. When combined with other ingredients of similar refractive index, it can form transparent gels. The extent of viscosity increase depends on the liquid’s polarity, with polar liquids generally requiring a higher concentration of colloidal silicon dioxide than nonpolar ones. Viscosity is largely unaffected by temperature, but changes in the system’s pH can influence it.

In aerosols, excluding those for inhalation, colloidal silicon dioxide is utilized to enhance particulate suspension, prevent hard settling, and reduce spray nozzle clogging. It also serves as a tablet disintegrant and an adsorbent dispersing agent for liquids in powders. In suppository formulations with lipophilic excipients, it is frequently added to increase viscosity, prevent sedimentation during molding, and slow the release rate. Additionally, colloidal silicon dioxide is used as an adsorbent in the preparation of wax microspheres, as a thickening agent for topical preparations, and to assist in the freeze-drying of nanocapsules and nanosphere suspensions.