 | |
 Zinc pyrithione dimer | |
| Names | |
|---|---|
| IUPAC name bis(2-pyridylthio)zinc 1,1'-dioxide | |
| Other names ZnP, Pyrithione Zinc, Zinc OMADINE, ZnPT | |
| Identifiers | |
3D model (JSmol) |
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| ChEMBL | |
| ChemSpider |
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| ECHA InfoCard | 100.033.324 |
| UNII | |
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| Properties | |
| C10H8N2O2S2Zn | |
| Molar mass | 317.70 g/mol |
| Appearance | colourless solid |
| Melting point | 240 °C (464 °F; 513 K) (decomposition)[1] |
| Boiling point | decomposes |
| 8 ppm (pH 7) | |
| Pharmacology | |
| D11AX12 (WHO) | |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Zinc pyrithione (orpyrithione zinc) is acoordination complex ofzinc. It hasfungistatic (inhibiting the division of fungal cells) andbacteriostatic (inhibiting bacterial cell division) properties and is used in the treatment ofseborrhoeic dermatitis[2] anddandruff.
Thepyrithione ligands, which are formallymonoanions, arechelated to Zn2+ viaoxygen andsulfur centers. In the crystalline state, zinc pyrithione exists as a centrosymmetric dimer (see figure), where each zinc is bonded to two sulfur and three oxygen centers.[3] In solution, however, the dimers dissociate via scission of one Zn-Obond.[citation needed]
This compound was first described in the 1930s.[4]
Pyrithione is theconjugate base derived from 2-mercaptopyridine-N-oxide (CAS# 1121-31-9), a derivative ofpyridine-N-oxide.[citation needed]
Zinc pyrithione can be used to treatdandruff andseborrhoeic dermatitis.[5][6][7] It also has antibacterial properties and is effective against manypathogens from theStreptococcus andStaphylococcus genera.[8] Its other medical applications include treatments ofpsoriasis,eczema,ringworm,fungus,athletes foot,dry skin,atopic dermatitis,tinea versicolor,[9][8] andvitiligo.[medical citation needed]
Because of its lowsolubility inwater (8 ppm at neutral pH), zinc pyrithione is suitable for use in outdoorpaints and other products that protect againstmildew andalgae. It is analgaecide. It is chemically incompatible with paints relying on metal carboxylate curing agents. When it is used in latex paints with water containing muchiron, a sequestering agent that preferentially binds the iron ions is needed. It is decomposed byultraviolet light slowly, providing years of protection in direct sunlight.[citation needed]
Zinc pyrithione is anantibacterial treatment for householdsponges, as used by the3M Corporation.[10][11]
A process to apply zinc pyrithione to cotton with washable results was patented in the United States in 1984.[12] Zinc pyrithione is used to prevent microbe growth inpolyester.[13] Textiles with applied zinc pyrithione protect against odor-causing microorganisms. Export of antimicrobial textiles reached US$497.4 million in 2015.[14]
Zinc pyrithione is known to exhibit antibacterial activity by disrupting cell membrane integrity and essential metabolic functions in bacteria.[15]
Its antifungal effect is thought to derive from its ability to disruptmembrane transport by blocking theproton pump that energizes the transport mechanism.[16] A study from 2011 showed that antifungal effects of zinc pyrithione work bycopper toxicity mechanism that targets criticaliron–sulphur proteins.[17]
Zinc pyrithione is approved forover-the-counter topical use in the United States as a treatment fordandruff and is the active ingredient in several anti-dandruff shampoos and body wash gels. In its industrial forms and strengths, it may be harmful by contact or ingestion. Zinc pyrithione can in the laboratory setting trigger a variety of responses, such as DNA damage in skin cells.[18]
Use of zinc pyrithione is prohibited within cosmetic products in theEuropean Union since December 2021.[19] The substance was considered safe for use in rinse-off and leave-in products of different tested concentrations, but due to potential environmental toxicity consideration of the use of zinc pyrithione was made against potential alternative substance ingredients. Due to no industry submission to the regulators supporting the continued use of zinc pyrithione and/or an absence of indications that there were no suitable alternatives to the substance: the use of zinc pyrithione became automatically prohibited within cosmetic products as an intended ingredient. This was as a consequence of zinc pyrithione addition to the Cosmetic Product Regulation (EC) No 1223/2009 Annex II list.[19]
Zinc pyrithione concentration of up to 2% is allowed for products when they are formulated to be applied and then washed off after brief exposure. Alternatively, up to 0.25 percent when formulated to be left on the skin or scalp[20]
A large Swedish study shows that it is broken down inwastewater plants and does not release into waterways.[21] A Danish study shows that it biodegrades quickly, but that a risk of continuous leaching from boat paint may cause environmental toxicity.[22]
