Mequinol

Mequinol, MeHQ or 4-methoxyphenol, is an organic compound with the formula CH₃OC₆H₄OH. It is a phenol with a methoxy group in the para position. A colorless solid, it is used in dermatology^[1] and organic chemistry.^[2]

Mequinol

Clinical data
Other names	4-Hydroxyanisole; para-Guaiacol
AHFS/Drugs.com	International Drug Names
MedlinePlus	a682437
Routes of administration	Topical
ATC code	D11AX06 (WHO)
Legal status
Legal status	CA: Unscheduled US: ℞-only and Unscheduled In general: unscheduled
Identifiers
IUPAC name 4-Methoxyphenol
CAS Number	150-76-5 Y
PubChem CID	9015
IUPHAR/BPS	6827
ChemSpider	8665 Y
UNII	6HT8U7K3AM
KEGG	D04926 Y
ChEMBL	ChEMBL544 Y
CompTox Dashboard (EPA)	DTXSID4020828
ECHA InfoCard	100.005.246
Chemical and physical data
Formula	C7H8O2
Molar mass	124.139 g·mol−1
Density	1.55 g/cm3
Melting point	52.5 °C (126.5 °F)
Boiling point	243 °C (469 °F)
InChI InChI=1S/C7H8O2/c1-9-7-4-2-6(8)3-5-7/h2-5,8H,1H3 Y Key:NWVVVBRKAWDGAB-UHFFFAOYSA-N Y
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Use in 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.^[1] Dermatologists commonly prescribe the drug to treat liver 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]

Organic chemistry

In organic chemistry 4-methoxyphenol is used as a polymerisation inhibitor (e.g. acrylates or styrene monomers).^[2]

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

Safety

The U.S. 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]

See also

• Monobenzone (benzyloxyphenol)
• Hydroquinone
• Guaiacol
• 2-Hydroxy-5-methoxybenzaldehyde