What is Monobenzone used for?

Monobenzone, also called 4-(Benzyloxy)phenol and monobenzyl ether of hydroquinone (MBEH) is an organic chemical in the phenol family. It is used as a topical drug for medical depigmentation. It is a colourless solid that is classified as the monobenzyl ether of hydroquinone. Monobenzone is soluble in alcohol, benzene, and diethyl ether, and practically insoluble in water.

Description

Monobenzone is the monobenzyl ether of hydroquinone used medically for depigmentation. Monobenzone occurs as a white, almost tasteless crystalline powder, soluble in alcohol and practically insoluble in water. It exerts a depigmenting effect on skin of mammals by increasing the excretion of melanin from the melanocytes. It may also cause destruction of melanocytes and permanent depigmentation. Monobenzone is the monobenzyl ether of hydroquinone. It is used as a topical drug for medical depigmentation. It has a role as a melanin synthesis inhibitor, a dermatologic drug and an allergen. It derives from a hydroquinone. 
Monobenzone has been used since the beginning of the 1950s to treat several forms of hyperpigmentation. After some years,many cases were being reported of dermatitis，depigmentation (long-lasting and sometimes permanent) and hyperpigmentation.From the 1970s on, it was, and still is used mainly to depigment residual pigmented areas in patients with very extensive therapy-resistant vitiligo. ln the USA and the Eu, its use in cosmetics has long been banned.

Pharmacology

The topical application of monobenzone in animals increases the excretion of melanin from melanocytes. The same action is thought to be responsible for the depigmenting effect of the drug in humans. Monobenzone may cause destruction of melanocytes and permanent depigmentation.

The histology of the skin after depigmentation with topical monobenzone is the same as that seen in vitiligo; the epidermis is normal except for the absence of identifiable melanocytes. Therefore, monobenzone is used as a topical medicine to permanently depigment normal skin surrounding vitiliginous lesions only in patients with disseminated (greater than 50 percent of body surface area) idiopathic vitiligo. Monobenzone is also being considered for the treatment of melanoma.

Mechanism of Action

Monobenzone is a monobenzyl ether of hydroquinone with topical depigmentation activity. Although the exact mechanism of action of depigmentation is unknown, the metabolites of monobenzone appear to have a cytotoxic effect on melanocytes. Furthermore, the depigmentation effect might be mediated through the inhibition of tyrosinase, which is essential in the synthesis of melanin pigments, thereby causing permanent depigmentation of the skin.

Other uses

Monobenzone is also used to derive dyes for fiber dyeing and is used in the rubber industry.