Chlorobutanol

• BPChlorobutanol
• BPAnhydrous Chlorobutanol
• JPChlorobutanol
• Ph. Eur.Chlorobutanol Hemihydrate
• Ph. Eur.Chlorobutanol, Anhydrous
• USP–NFChlorobutanol

acetone chloroform; chlorbutol; chlorobutanolum; 1,1,1-trichloro-2-methyl-2-propanol; trichloro-tert-butyl alcohol

1,1,1-Trichloro-2-methylpropan-2-ol · [57-15-8]

UNII HM4YQM8WRC · PubChem CID 5977

C4H7Cl3O (anhydrous); C4H7Cl3O·½H2O (hemihydrate) · 177.46 (anhydrous); 186.46 (hemihydrate)

Antimicrobial preservative

Typical concentrations: up to 0.5% · Dosage forms: Sterile (parenteral/ophthalmic)

An antimicrobial preservative, with both antibacterial and antifungal activity, used mainly at 0.5% w/v in injections, ophthalmic and nasal preparations and other liquid products. It also has mild sedative and local anaesthetic properties and is used as a plasticiser for cellulose esters.

Colourless or white crystals or crystalline powder with a characteristic, somewhat camphoraceous odour. It is volatile and sublimes readily.

Melting point

about 95–97 °C (anhydrous); about 76–78 °C (hemihydrate)

Boiling point

about 167 °C

Solubility

slightly soluble in water (about 1 in 125); very soluble in ethanol; soluble in glycerol, ether, chloroform and volatile oils

Volatility

sublimes readily at room temperature

Effective pH range

antimicrobial activity is good below about pH 5.5 and falls as pH rises

Volatile: losses occur from solutions by evaporation, during autoclaving and through permeable plastic containers and rubber closures. In aqueous solution it is stable at about pH 3, but base-catalysed hydrolysis becomes increasingly rapid as pH rises, releasing hydrochloric acid. Store in a well-closed container in a cool place.

Sorbed by plastic containers, particularly polyethylene, and by rubber closures, and by polyhydroxyethyl methacrylate used in soft contact lenses. Its activity is reduced by bentonite, magnesium trisilicate, carboxymethylcellulose and polysorbate 80.

Prepared by condensation of acetone and chloroform in the presence of solid potassium hydroxide.

At the preservative concentration of 0.5% it is generally well tolerated, although hypersensitivity reactions have been reported. Larger systemic doses cause sedation and CNS depression, and the drug has a long elimination half-life, so cumulative exposure from frequently dosed parenteral products should be considered.

Observe normal precautions for the quantity handled. It is irritant to the eyes, skin and respiratory tract; wear eye protection and gloves and handle in a well-ventilated area.

Included in the FDA Inactive Ingredient Database (injections, nasal, ophthalmic and topical preparations) and in parenteral and non-parenteral medicines licensed in Europe.

Benzyl alcohol; phenylethyl alcohol; chlorocresol.

Chlorobutanol dissolves slowly in water; warming speeds this up but increases loss by volatilisation, so dissolve it in a closed vessel or in a small amount of ethanol first. Use glass containers where possible and allow for losses during autoclaving and storage, especially in near-neutral solutions.