Chloroxylenol

• BPChloroxylenol
• USP–NFChloroxylenol

PCMX; p-chloro-m-xylenol; 4-chloro-3,5-xylenol; parachlorometaxylenol

4-Chloro-3,5-dimethylphenol · [88-04-0]

UNII 0F32U78V2Q · PubChem CID 2723

C8H9ClO · 156.61

Antimicrobial preservative

Typical concentrations: — · Dosage forms: Semi-solid

A phenolic antimicrobial used as a preservative in topical creams, lotions and shampoos, typically at about 0.1–0.8%, and as the active ingredient of antiseptic and disinfectant products such as skin cleansers and hand washes; Chloroxylenol Solution BP contains 5% w/v solubilised with soap, terpineol and alcohol.

White or creamy-white crystals or crystalline powder with a characteristic phenolic odour. It is volatile in steam.

Melting point

about 114–116 °C

Boiling point

about 246 °C

Solubility

very slightly soluble in water; freely soluble in ethanol and ether; soluble in terpenes, fixed oils and alkali hydroxide solutions

Antimicrobial spectrum

mainly Gram-positive bacteria; less active against Gram-negative bacteria, especially Pseudomonas; some antifungal activity

Stable under normal conditions. Store in a well-closed container, protected from light, in a cool, dry place.

Its activity is reduced by non-ionic surfactants and methylcellulose, by partitioning into oils, and by organic matter. It is incompatible with strong oxidising agents and strong bases.

Prepared by chlorination of 3,5-dimethylphenol (sym-m-xylenol).

Generally well tolerated on the skin at the concentrations used, but it can cause irritation and allergic contact dermatitis. Ingestion of concentrated antiseptic solutions has caused serious poisoning.

Observe normal precautions for the quantity handled. The powder irritates the eyes, skin and respiratory tract; wear eye protection and gloves and avoid generating dust.

Used in topical medicines and antiseptic products in the UK and elsewhere. In the USA it is an active ingredient of over-the-counter antiseptic products, and its status in consumer and health-care antiseptic washes has been under FDA review. Permitted as a preservative in cosmetics in the EU within set limits.

Chlorocresol; dichloroxylenol; phenol; triclosan.

Its very low water solubility means it is usually formulated with soaps, surfactants or alcohol; the ratio of surfactant to chloroxylenol must be balanced, because excess surfactant traps the phenol in micelles and lowers activity.