Simethicone is a mixture of polydimethylsiloxane and hydrated silica, available as emulsions (e.g., 30%, 50%) or as a 100% active powder. It is a white to greyish-white, viscous, semi-liquid or free-flowing powder, depending on the form. It is odorless and tasteless.
Chemical Name and CAS Registry Number:Â Polydimethylsiloxane with silica [8050-81-5]
Functional Category:Antifoaming agent; antiflatulent
Identification: Infrared spectroscopy and chemical tests
Viscosity (if liquid): 100–1000 cSt
Loss on Drying: NMT 5% (for powder)
Silica Content (for powder): ~4–7%
pH (emulsion): Typically neutral (~6.5–7.5)
Microbial Limits: Complies with pharmacopeial guidelines
Used as an oral antiflatulent to relieve gas and bloating.
Included in chewable tablets, capsules, suspensions, and emulsions.
Acts as a process aid to reduce foaming in manufacturing.
Common concentrations:
30% emulsion: Used in oral drops and suspensions.
50% emulsion: Used in more concentrated liquid oral formulations.
100% powder: Incorporated into solid dosage forms (tablets/capsules).
Simethicone is physiologically inert, non-absorbable, and generally well-tolerated. It works by decreasing surface tension, allowing gas bubbles in the GI tract to coalesce and be expelled. It is not systemically absorbed and is often combined with antacids. Emulsion forms require antimicrobial preservatives for stability.
