Colloidal Silicon Dioxide

Category

Thickening Agents; Suspending Agents

Molecular Formula

SiO2

Molecular Weight

60.08

Grade

Pharmceutical Excipients

UNII

ETJ7Z6XBU4

Chemical Name

Silica

CAS Number

7631-86-9

Synonyms

Aerosil; colloidal silica; fumed silica; fumed silicon dioxide; hochdisperses silicum dioxid; SAS; silica colloidalis anhydrica; silica sol; silicic anhydride; silicon dioxide colloidal; silicon dioxide fumed; synthetic amorphous silica; Wacker HDK

Administration route

Oral, inhalation, percutaneous, sublingual, vaginal

Dosage Form

Oral capsules, suspensions and tablets; Transdermal and vaginal administration preparations

Source and Preparation

Colloidal silica is prepared by the vapor hydrolysis of chlorosilane, such as silicon tetrachloride, at 1800℃ with hydrogen, oxygen flame combustion preparation.

Applications

This product is widely used in pharmaceutical, cosmetic and food products. The small particle size and large specific surface area give it the desired fluidity, which can be used to improve the fluidity of dry powder in many processes, such as sheet pressing. It can also be used to stabilize emulsions, as thixotropic thickening agent and suspension aid in gels and semi-solid preparations. Transparent gels can be formed with other components with similar refractive indices. The increase in viscosity depends on the polarity of the liquid (polar liquids require a higher concentration of differential silica gel than non-polar liquids). Viscosity is not affected by temperature, but changes in pH of the system will affect viscosity. In non-inhalation aerosols, this product is often used to promote the suspension of particles, so as to avoid hard precipitation and less nozzle clogging. It can also be used as a disintegrator for tablets and as an adsorptive dispersant for liquids in dispersions. This product is also often used in suppositories containing lipophilic substrates to increase viscosity to avoid precipitation during molding and decrease release rate.

Safety

Colloidal silica is widely used in oral and topical preparations, and is generally considered to be non-toxic and non-irritating excipients. However, abdominal and subcutaneous injection may cause local tissue necrosis and granuloma, so silica should not be used for injection. LD50 (rat, IV) : 15mg/kg LD50 (rat, oral) : 3.16g/kg

Incompatibilities

Incompatibility with diethyldiethylstilbestrol.