Selenium sulfide
From Wikipedia, the free encyclopedia
Selenium sulfide (also selenium sulphide; see spelling), a loose name for what is technically selenium disulfide or selenium (IV) sulfide, formula SeS2 [1][2], is an antifungal agent often used in shampoos for the treatment of dandruff and seborrheic dermatitis associated in the scalp with Malassezia genus fungi. [3] In the United States, a 1% strength is available over-the-counter, and a 2.5% strength is also available with a prescription. At the 2.5% strength, selenium (IV) sulfide is also used on the body to treat tinea versicolor, a type of fungal skin infection caused by a different species of Malassezia.
It can be used for adults and children over the age of 5. It should be used twice a week for the first two weeks then once a week for the next two weeks.
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[edit] Chemical composition
Selenium sulfide has a composition that approximates to SeS2 and is sometimes called selenium disulfide. However as used in proprietary formulations it is not a pure chemical compound but is a mixture of chemical compounds where the overall Se:S ratio is 1:2. The compounds are cyclic Se−S rings containing a variable number of S and Se atoms, SenS8−n.[4] The formal oxidation state of +4 can be assigned from the stoichiometry and therefore the mixture is sometimes called selenium(IV) sulfide.[5][6], Selenium sulfide can cause discoloration of the hair and alter the color of hair dyes. It may also discolor metallic jewellery. It should not be used in the first 3 months of pregnancy.
[edit] Confusion with selenium(II) sulfide (selenium monosulfide), a carcinogen
Selenium monosulfide (SeS) is the only selenium compound so far identified as a carcinogen in animals. [7] Selenium monosulfide, along with elemental selenium and sulfur has been used in medicinal preparations in the past [8], causing confusion and contradiction [9] as to exactly what form selenium is in, in any given topical preparation.[10]
[edit] See also
- Zinc pyrithione, an antimicrobial agent used in some medicated shampoos, which can be used by all patients of any age. It should be used daily until the dandruff has gone.
[edit] Footnotes
- ^ Selenium(IV) sulfide - pharmacy codes search engine
- ^ Chemicals of Selenium .Se
- ^ Accessed Dec. 24, 2007
- ^ Cyclic selenium sulfides R. Steudel, R. Laitinen, Topics in Current Chemistry, (1982), 102, 177-197
- ^ Selenium(IV) sulfide - pharmacy codes search engine
- ^ Chemicals of Selenium .Se
- ^ http://www.scorecard.org/chemical-profiles/html/selenium.html
- ^ Definition: selenium sulfide from Online Medical Dictionary
- ^ DrugBank: DB00971 (Selenium Sulfide)
- ^ selenium sulfide: Definition and Much More from Answers.com
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