Name: Chloroxylenol
CAS No: 4-Chloro-3,5-xylenol [88-04-0]
BP: Chloroxylenol USP: Chloroxylenol
4-Chloro-3,5-dimethylphenol; 2-chloro-5-hydroxy-1,3-dimethylbenzene; 4-chloro-1-hydroxy-3,5-dimethylbenzene; 2-chloro-5- hydroxy-m-xylene; 2-chloro-m-xylenol; 3,5-dimethyl-4-chlorophenol; Nipacide PX; parachlorometaxylenol; p-chloro-m-xylenol; PCMX.
4-Chloro-3,5-xylenol [88-04-0]
C8H9ClO 156.61
Chloroxylenol is a common constituent of many proprietary disinfectants used for skin and wound disinfection; see Table I. As a pharmaceutical excipient, chloroxylenol is commonly used in low concentrations as an antimicrobial preservative in topical formulations such as creams and ointments. Chloroxylenol is also used in a number of cosmetic formulations. Therapeutically, chloroxylenol has been investigated as a treatment for acne vulgaris,(1,2) for treating infected root canals,(3) and as an antifungal agent when impregnated into medical devices.(4) Chloroxylenol is included in drug products approved for topical antifungal, topical acne and topical dandruff/seborrheic dermatitis/psoriasis treatments.(5)
White or cream-colored crystals or crystalline powder with a characteristic phenolic odor. Volatile in steam.
See Table II.
Antimicrobial activity Chloroxylenol is effective against Grampositive bacteria but less active against Gram-negative bacteria. The activity of chloroxylenol against Gram-negative bacilli can be increased by the addition of a chelating agent such as edetic acid.(6) Chloroxylenol is inactive against bacterial spores. Antimicrobial activity may be reduced by loss of chloroxylenol from a formulation due to incompatibilities with packaging materials or other excipients, such as nonionic surfactants.(7) Solution pH does not have a marked effect on the activity of chloroxylenol.(8) For reported minimum inhibitory concentrations (MICs), see Table III. Boiling point 2468C Density 0.89 g/cm3 at 208C(10) Melting point 115.58C Partition coefficient Octanol : water log kow = 3.27(10) Solubility Freely soluble in ethanol (95%); soluble in ether, terpenes, and fixed oils; very slightly soluble in water. Dissolves in solutions of alkali hydroxides. See also Table IV.
Chloroxylenol is stable at normal room temperature, but is volatile in steam. Contact with natural rubber should be avoided. Aqueous solutions of chloroxylenol are susceptible to microbial contamination and appropriate measures should be taken to prevent contamination during storage or dilution. Chloroxylenol should be stored in polyethylene, mild steel or stainless steel containers, which should be well-closed and kept in a cool, dry place. Chloroxylenol does not absorb at wavelengths >290 nm and has been reported to be stable to sunlight for up to 24 hours.(10)
Chloroxylenol has been reported to be incompatible with nonionic surfactants and methylcellulose.
Chloroxylenol is prepared by treating 3,5-dimethylphenol with chlorine or sulfuryl chloride (SO2Cl2).
Chloroxylenol is generally regarded as a relatively nontoxic and nonirritant material when used as an excipient in topical products. However, chloroxylenol has been placed in Toxicity Category I for eye irritation effects.(11) In addition, allergic skin reactions have been reported.(12–16) Taken orally, chloroxylenol is mildly toxic and ingestion of a chloroxylenol-containing disinfectant product has been associated with reports of fatal(17) or severe instances of selfpoisoning.(18,19) LD50 (mouse, IP): 0.115 g/kg(20) LD50 (rat, dermal): >2.0 g/kg(10) LD50 (rat, oral): 3.83 g/kg(20)
Observe normal precautions appropriate to the circumstances and quantity of material handled. Chloroxylenol is an eye irritant, and eye protection is recommended. When heated to decomposition, chloroxylenol emits toxic fumes.
Included in the FDA Inactive Ingredients Database (otic preparations; topical creams and emulsions). Included in nonparenteral medicines licensed in the UK. Approved in Europe as a preservative in cosmetics with a maximum authorized concentration of 0.5%.(21
Chlorocresol
The EINECS number for chloroxylenol is 201-793-8. The PubChem Compound ID (CID) for chloroxylenol described in this monograph is 2723.