Zinc pyrithione

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ImageFile = Zink-Pyrithion.svg
ImageSize =
ImageFile1 = Zinc-pyrithione-dimer-3D-balls.png ImageSize1 = 250
IUPACName = bis(2-pyridylthio)zinc 1,1'-dioxide
OtherNames = ZnP, pyrithione zinc, zinc OMADINE
Section1 = Chembox Identifiers
CASNo = 13463-41-7
PubChem = 26041
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Section2 = Chembox Properties
Formula = C₁₀H₈N₂O₂S₂Zn
MolarMass = 317.70 g/mol
Appearance = colourless solid
Density =
MeltingPt = 240 °C (decomp.) Thieme Chemistry (Hrsg.): "Römpp Online." Version 3.1. Georg Thieme Verlag, Stuttgart 2007.]
BoilingPt = decomp.
Solubility = 8 ppm (pH 7)
Section3 = Chembox Hazards
MainHazards =
FlashPt =
Autoignition =

Zinc pyrithione is a coordination complex of zinc. This colourless solid is used as an antifungal and antibacterial agent. This coordination complex, which has many names, was first reported in the 1930s. [cite web |url=http://www.cas.astate.edu/draganjac/pyrithionezinc.html |title=astate.edu |accessdate=2007-08-24 |format= |work=] [cite web |url=http://www.wisegeek.com/what-is-skin-zinc.htm |title=What is Skin Zinc? |accessdate=2007-08-24 |format= |work=]

tructure of the compound

The pyrithione ligands, which are formally monoanions, are chelated to Zn²⁺ via oxygen and sulfur centers. In the crystalline state, zinc pyrithione exists a centrosymmetric dimer (see figure). Each zinc is bonded to two sulfur and three oxygen centers. [cite journal |title= Structural characterization of bis(N-oxopyridine-2-thionato)zinc(II) |authors= Barnett, B. L.; Kretschmar, H. C.; Hartman, F. A. |journal= Inorg. Chem. |year= 1977 |volume= 16 |issue= 8 |pages= 1834–1838 |doi= 10.1021/ic50174a002] In solution, however, the dimers dissociate via scission of one Zn-O bond.

Pyrithione is the conjugate base derived from 2-mercaptopyridine-N-oxide (CAS# 1121-31-9), a derivative of pyridine-"N"-oxide.

Uses

Medical

Zinc pyrithione is best known for its use in treating dandruff and seborrheic dermatitis. It also has antibacterial properties and is effective against many pathogens from the streptococcus and staphylococcus class. Its other medical applications include treatments of psoriasis, eczema, ringworm, fungus, athletes foot, dry skin, atypical dermatitis, tinea, and vitiligo.

Zinc pyrithione is approved for over-the-counter topical use in the United States as a treatment for dandruff. It is the active ingredient in several anti-dandruff shampoos such as Head & Shoulders. However, in its industrial forms and strengths, it may be harmful by contact or ingestion.

In paint

Due to its low solubility in water (8 ppm at neutral pH), zinc pyrithione is suitable for use in outdoor paints and other products that provide protection against mildew and algae. It is an effective algaecide. It is chemically incompatible with paints relying on metal carboxylate curing agents. When used in latex paints and the water contains high amount of iron, a sequestering agent that will preferentially bind the iron ions is needed. Its decomposition by ultraviolet light is slow, providing years of protection even against direct sunlight.

In sponges

Zinc pyrithione is also used as an antibacterial treatment for household sponges, most notably by the 3M Corporation. [ [http://legalminds.lp.findlaw.com/list/epa-pest/msg01049.html Notice of Filing a Pesticide Petition to Establish ] ]

Mechanism of action

Its antifungal effect is proposed to derive from its ability to disrupt membrane transport by blocking the proton pump that energizes the transport mechanism. [cite journal |author=Chandler CJ, Segel IH |title=Mechanism of the antimicrobial action of pyrithione: effects on membrane transport, ATP levels, and protein synthesis |journal=Antimicrob. Agents Chemother. |volume=14 |issue=1 |pages=60–8 |year=1978 |pmid=28693 |doi= |url=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=28693 ] Fungi are capable of inactivating pyrithione in low concentrations.

References

External links

* [http://www.pesticideinfo.org/Detail_Chemical.jsp?Rec_Id=PC34738#Toxicity Some toxicity information on industrial uses]
* [http://scienceblogs.com/omnibrain/2007/04/dandruff_shampoo_to_calm_seizu.php Article Omni Brain: Dandruff Shampoo to Calm Seizures, Apr. 2007]