Cetrimide

• BPCetrimide
• Ph. Eur.Cetrimide

alkyltrimethylammonium bromide; Cetavlon; cetrimidum; trimethyltetradecylammonium bromide

Mixture of alkyltrimethylammonium bromides, mainly tetradecyltrimethylammonium bromide, with smaller amounts of dodecyl- and hexadecyltrimethylammonium bromides · [8044-71-1]

C17H38BrN (tetradecyl compound) · 336.40 (tetradecyl compound)

Antimicrobial preservative, Surfactant, emulsifier

Typical concentrations: — · Dosage forms: Semi-solid, Sterile (parenteral/ophthalmic)

A quaternary ammonium antiseptic and cationic surfactant used in topical antiseptic creams and solutions (typically 0.1–1.0%), in wound and skin cleansers, and in medicated shampoos for seborrhoea and dandruff; it has also been used as an antimicrobial preservative in eye drops at about 0.005% w/v. It is frequently combined with chlorhexidine.

A white to creamy-white, voluminous, free-flowing powder with a faint characteristic odour and a bitter, soapy taste.

Solubility

freely soluble in water and ethanol; practically insoluble in ether

Surface activity

cationic surfactant; aqueous solutions foam strongly on shaking

Antimicrobial spectrum

mainly Gram-positive bacteria; less active against Gram-negative bacteria, with Pseudomonas species notably resistant; some antifungal activity

Stable as the solid. Aqueous solutions are stable and may be sterilised by autoclaving, but dilute solutions can become contaminated with resistant organisms such as Pseudomonas and should be protected from contamination. Store in a well-closed container in a cool, dry place.

Incompatible with soaps and other anionic surfactants, high concentrations of non-ionic surfactants, bentonite, iodine, phenylmercuric nitrate, alkali hydroxides and acid dyes. Its activity is also reduced by organic matter such as blood and by adsorption onto some materials.

Prepared by reacting trimethylamine with the appropriate alkyl bromides (quaternisation), mainly tetradecyl bromide.

At the concentrations used topically cetrimide is generally well tolerated, but concentrated solutions irritate the skin and eyes and can cause burns, and hypersensitivity reactions have been reported. Ingestion can cause nausea, vomiting and, in large amounts, CNS depression and other serious effects.

Observe normal precautions for the quantity handled. The powder is irritant to the eyes, skin and respiratory tract; wear eye protection and gloves and avoid inhaling the dust.

Included in non-parenteral medicines licensed in the UK and Europe, mainly topical antiseptic preparations.

Benzalkonium chloride; benzethonium chloride; cetylpyridinium chloride; cetrimonium bromide (cetyltrimethylammonium bromide).

Cetrimide is the mixed material described in the BP and Ph. Eur.; it should not be confused with pure cetrimonium bromide, the C16 compound. Avoid using it with anionic ingredients such as sodium lauryl sulfate or carbomers, and protect dilute solutions from contamination, for example by adding ethanol or isopropyl alcohol or by preparing them freshly.