Mequinol

Mequinol, MEHQ or 4-Methoxyphenol, is a phenol used in dermatology and organic chemistry.

Uses

Dermatology

Mequinol is a common active ingredient in topical drugs used for skin depigmentation. As a topical drug Mequinol is often mixed with tretinoin, a topical retinoid. A common formulation for this drug is an ethanolic solution of 2% Mequinol and 0.01% tretinoin by mass.Dermatologists commonly prescribe the drug to treat solar lentigines, liver spots, or age spots.

Lower dosages of mequinol have been used in conjunction with a Q-switched laser to depigment skin in patients with disseminated idiopathic vitiligo.

Organic chemistry

In organic chemistry 4-methoxyphenol is used to inhibit the radical polymerization of monomers (e.g. acrylates or styrene monomers).

Preparation

4-Methoxyphenol is produced from p-benzoquinone and methanol via a free radical reaction.

Safety

People can be exposed to 4-methoxyphenol in the workplace by breathing it in, skin absorption, swallowing it, skin contact, and eye contact. The National Institute for Occupational Safety and Health (NIOSH) has set a recommended exposure limit (REL) of 5 mg/m³ over an 8-hour workday.