Cetrimonium bromide cream

Dissolve chlorhexidin diacetate in propylene glycol at 70°C, stir well, and slowly add Lutrol F 127 and water. 

Maintain the temperature until the air bubbles escape. A clear colorless gel is obtained. 

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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. 

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