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Simethicone

    Synonyms: Dow Corning Q7-2243 LVA; Dow Corning Q7-2587; polydimethylsiloxane–silicon dioxide mixture; Sentry Simethicone; simeticonum.

    Description: Simethicone occurs as a translucent, gray-colored, viscous fluid. It has a molecular weight of 14 000–21 000.

    Chemical Name: a-(Trimethysilyl-o-methylpoly[oxy(dimethylsilylene)], mixture with silicon dioxide

    Antifoaming agent; tablet diluent; water-repelling agent.

    • The main use of simethicone as an excipient is as an antifoaming agent in pharmaceutical manufacturing processes, for which 1–50 ppm is used.

    • Therapeutically, simethicone is included in a number of oral pharmaceutical formulations as an antiflatulent, although its therapeutic benefit is questionable.

    • It is also included in antacid products such as tablets or capsules.

    • In some types of surgical or gastroscopic procedures where gas is used to inflate the body cavity, a defoaming preparation containing simethicone may be used in the area to control foaming of the fluids.

    • When simethicone is used in aqueous formulations, it should be emulsified to ensure compatibility with the aqueous system and components.

    Simethicone as supplied is not generally compatible with aqueous systems and will float like an oil on a formulation unless it is first emulsified. It should not be used in formulations or processing conditions that are very acidic (below pH 3) or highly alkaline (above pH 10), since these conditions may have some tendency to break the polydimethylsiloxane polymer. Simethicone cannot normally be mixed with polar solvents of any kind because it is very minimally soluble. Simethicone is incompatible with oxidizing agents

    Simethicone is used in cosmetics, foods, and oral and topical pharmaceutical formulations, and is generally regarded as a relatively nontoxic and nonirritant material when used as an excipient. Direct contact with the eye may cause irritation.

    Observe normal precautions appropriate to the circumstances and quantity of material handled. Eye protection and gloves are recommended. Simethicone should be handled in areas with adequate ventilation.

    Cyclomethicone; dimethicone.