Mequinol

Mequinol
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Systematic (IUPAC) name
	4-Methoxyphenol
Clinical data
AHFS/Drugs.com	International Drug Names
MedlinePlus	a682437
Legal status	CA: Unscheduled; US: Rx-only, Unscheduled; Unscheduled;
Routes of; administration	Topical
Identifiers
CAS Number	150-76-5
ATC code	D11AX06 (WHO)
PubChem	CID: 9015
IUPHAR/BPS	6827
ChemSpider	8665
UNII	6HT8U7K3AM
KEGG	D04926
ChEMBL	CHEMBL544
Synonyms	4-Hydroxyanisole; para-Guaiacol
Chemical data
Formula	C7H8O2
Molecular mass	124.13722 g/mol
	InChI InChI=1S/C7H8O2/c1-9-7-4-2-6(8)3-5-7/h2-5,8H,1H3 ; Key:NWVVVBRKAWDGAB-UHFFFAOYSA-N ;
Physical data
Density	1.55 g/cm3
Melting point	52.5 °C (126.5 °F)
Boiling point	243 °C (469 °F)
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Mequinol, MEHQ or 4-Methoxyphenol, is a phenol used in dermatology^[1] and organic chemistry.^[2]

Uses

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.^[1] 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.^[3]

In organic chemistry 4-methoxyphenol is used to inhibit the radical polymerization of monomers (e.g. acrylates or styrene monomers).^[2]

4-Methoxyphenol is produced from p-benzoquinone and methanol via a free radical reaction.^[4]^[5]

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.^[6]