Quaternary ammonium compounds cetrimide

Also used in combination with other agents e.g. chlorhexidine, iodine, t Several forms available having x% chlorhexidine and 10x% cetrimide. QAC, quaternary ammonium compound. 

Fig. 10.8 Quaternary ammonium compounds (QACs) A, general structure ofQACs B, benzalkonium chloride (n - S - 18) C, cetrimide (n - 12 - 14 or 16) D, cetylpyridinium chloride.

Quaternary ammonium compounds (QACs Chapter 10) such as cetrimide, and also the bisbiguanide, chlorhexidine, are notoriously prone to promote clumping. A non-ionic surface-active agent of the type formed by condensing ethylene oxide with a long-chain fatty acid such as Cirrasol ALN-WF (ICI Ltd), formerly known as Lubrol W, together with lecithin, added to the diluting fluid has been used to overcome this effect. 

Benzalkonium chloride is a quaternary ammonium compound used in pharmaceutical formulations as an antimicrobial preservative in applications similar to other cationic surfactants, such as cetrimide. 

Cetrimide is a quaternary ammonium compound that is used in cosmetics and pharmaceutical formulations as an antimicrobial preservative see Section 10. It may also be used as a cationic surfactant. In eye-drops, it is used as a preservative at a concentration of 0.005 % w/v. 

Most adverse effects reported relate to the therapeutic use of cetrimide. If ingested orally, cetrimide and other quaternary ammonium compounds can cause nausea, vomiting, muscle paralysis, CNS depression, and hypotension concentrated solutions may cause esophageal damage and necrosis. The fatal oral human dose is estimated to be 1.0-3.0g. ... 

Several case reports and patients series describe contact allergy to quaternary ammonium compounds (Wahlberg 1962 Huriez et al. 1965 Afzelius and Thulin 1979). In the study by Huriez et al. (1965) a series of 71 patients cethex-onium bromide was the main culprit. Cetrimonium bromide (cetrimide BP), another quaternary ammonium compound consisting of a mixture of chemicals (Cruisk-SHANK 1949), caused several cases of contact allergy (Morgan 1968). 

Cetrimonium bromide (cetrimide, Bromat, Cetab, Cetavlon, Cetylamine, C.T.A.B., Lissolamine V, Micol, Quamonium, CAS no. 57-09-0). It is easily soluble in water, in concentrations of 1-40%. Concentrations greater than 1% in quaternary ammonium compounds are very irritant under occlusion (Polano 1984). Savlon is a mixture of cetrimide 15% w/v and chlorhexidine 1.5% w/v aqua. Patch-test concentrations are 0.01 and 0.1% aqua. Allergic reactions are uncommon. 

In small-scale preparation the quaternary ammonium compounds containing an alkyl chain are the most important. Cetrimide (Cetrimonium bromide, see Fig. 23.8) is used in a concentration of 0.5-2 % as emulsifier in creams. Quaternary ammonium compounds of this type are used from a concentration of 0.004 %. They also exhibit antiseptic and preservative properties. Notably benzalkonium chloride, as well as being a surfactant of the oil-in-water emulsifying type, is also important as a preservative in for example eye and nose drops. Catioiuc-active compounds are often incompatible with anionic substances such as sulfobituminose ammonium due to the risk of the formation of insoluble ion pairs. Since it is often difficult to estimate this risk, it is better to avoid these combinations. 

Fig. 10.8 A where the R substituents are alkyl or heterocyclic radicals to give compounds such as cetyltrimethylammonium bromide (cetrimide), cetylpyridinium chloride and benzalkonium chloride. Inspection of the stmctures of these compounds (Fig. 10.8B) indicates the requirement for good antimicrobial activily of having a chain length in the range Cg to Cig in at least one of the R substituents. In the pyridinium compounds (Fig. 10.8C) three of the four covalent links may be satisfied by the nitrogen in a pyridine ring. Polymeric quaternary ammonium salts such as polyquatemium 1 are finding increasing use as preservatives.

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