Phenol

Synonyms: Carbolic acid; hydroxybenzene; oxybenzene; phenic acid; phenolum; phenyl hydrate; phenyl hydroxide; phenylic acid; phenylic alcohol.

Description: Phenol occurs as colorless to light pink, caustic, deliquescent needleshaped crystals or crystalline masses with a characteristic odor. When heated gently phenol melts to form a highly refractive liquid. The USP 32 permits the addition of a suitable stabilizer; the name and amount of substance used for this purpose must be clearly stated on the label.

Chemical Name: Phenol

Antimicrobial preservative; disinfectant.

• Phenol is used mainly as an antimicrobial preservative in parenteral pharmaceutical products.

• It has also been used in topical pharmaceutical formulations and cosmetics.

• Phenol is widely used as an antiseptic, disinfectant, and therapeutic agent, although it should not be used to preserve preparations that are to be freeze-dried.

Phenol undergoes a number of chemical reactions characteristic of alcohols; however, it possesses a tautomeric enol structure that is weakly acidic. It will form salts with sodium hydroxide or potassium hydroxide, but not with their carbonates or bicarbonates.

Phenol is highly corrosive and toxic, the main effects being on the central nervous system. The lethal human oral dose is estimated to be 1 g for an adult. Phenol is absorbed from the gastrointestinal tract, skin, and mucous membranes, and is metabolized to phenylglucuronide and phenyl sulfate, which are excreted in the urine.

Phenol is toxic on contact with the skin or if swallowed or inhaled. Phenol is strongly corrosive, producing possibly irreversible damage to the cornea and severe skin burns, although the skin burns are painless owing to the anesthetic effects of phenol. Phenol should be handled with caution, particularly when hot, owing to the release of corrosive and toxic fumes. The use of fume cupboards, enclosed plants, or other environmental containment is recommended. Protective polyvinyl chloride or rubber clothing is recommended, together with gloves, eye protection, and respirators. Spillages on the skin or eyes should be washed with copious amounts of water. Affected areas of the skin should be washed with water followed by application of a vegetable oil. Medical attention should be sought.

Liquefied phenol.