PYRITHIONE

Pyrithione is an organosulfur heterocycle used primarily as an antimicrobial and antifungal active in industrial preservation systems, and Pyrithione is valued for broad-spectrum control of bacteria, fungi, and algae in water-based products.
Pyrithione is commonly used as the active moiety in pyrithione salts such as sodium pyrithione and zinc pyrithione, and Pyrithione performance depends on the counterion form, pH, dosage, and compatibility with the complete formulation.
Pyrithione is typically supplied and applied as a stabilized salt solution or dispersion rather than as the free acid, and Pyrithione handling requires careful control because biocidal actives can cause irritation and have aquatic toxicity concerns.

CAS Number: 1121-30-8
EC Number: 214-328-9
Molecular Formula: C5H5NOS (free acid form; salt forms vary by counterion)
Molecular Weight: 127.16 g/mol (free acid form; salt forms vary by counterion)

Synonyms: Pyrithione, 1-Hydroxy-2(1H)-pyridinethione, 2-Pyridinethiol 1-oxide, 2-Mercaptopyridine N-oxide, Pyridine-2-thiol N-oxide, Pyrithione Active, Pyrithione Biocide, Pyrithione Antimicrobial, Pyrithione Antifungal, Pyrithione Preservative, Pyrithione N-oxide, Pyrithione (salt-dependent naming), Pyrithione, 2-Pyridinethiol 1-Oxide, 2-Mercaptopyridine N-Oxide, 2-Mercaptopyridine 1-Oxide, Pyridine-2-thiol 1-Oxide, Pyridine-2-thione 1-Oxide, 1-Hydroxy-2-pyridinethione, 1-Hydroxypyridine-2-thione, 2-Pyridinethione 1-Oxide, 2-Pyridylthio N-Oxide, 2-Pyridylthiol N-Oxide, Pyrithione Acid, Pyrithione Free Acid, Omadine, Omadine Acid, Pyridinethione N-Oxide, Pyridinethione Oxide, Mercaptopyridine Oxide, Mercaptopyridine N-Oxide, Pyridine Thione N-Oxide, Pyrithione Antimicrobial, Pyrithione Biocide, Pyrithione Preservative, Pyrithione Fungicide, Pyrithione Antifungal Agent, Pyrithione Antibacterial Agent, Pyrithione Industrial Grade, Pyrithione Technical Grade, Pyrithione Chemical Grade, Pyrithione Reagent Grade, Pyrithione High Purity, High Purity Pyrithione, Pyrithione Pure, Pure Pyrithione, Pyrithione Powder, Pyrithione Solid, Pyrithione CAS 1121-31-9, 2-Pyridinethiol 1-Oxide CAS 1121-31-9, 2-Mercaptopyridine N-Oxide CAS 1121-31-9, 1-Hydroxy-2-pyridinethione CAS 1121-31-9, Pyrithione Intermediate, Pyrithione Synthesis Grade, Pyrithione for Synthesis, Pyrithione Preservative Intermediate, Pyrithione Antimicrobial Intermediate, Pyrithione Cosmetic Intermediate, Pyrithione Personal Care Intermediate

APPLICATIONS

Pyrithione is used in water-based paints and coatings to protect against in-can spoilage caused by bacteria and fungi.
Pyrithione is incorporated into exterior coatings to help control algae and fungal growth on coated surfaces in compatible systems.
Pyrithione is used in primer and architectural coating formulations to improve shelf stability and reduce odor associated with microbial contamination.

Pyrithione is used in adhesives and sealants to prevent microbial degradation and viscosity loss in water-based products.
Pyrithione is incorporated into latex and emulsion adhesive systems to protect stored product and improve stability under warm storage conditions.
Pyrithione is used in construction sealants in selected formulations to reduce mold and mildew growth on exposed surfaces.

Pyrithione is used in polymer dispersions and latex systems to protect against bacterial spoilage during storage and transport.
Pyrithione is incorporated into binder dispersions to maintain consistent pH, viscosity, and odor profile in compatible systems.
Pyrithione is used in thickener-containing water-based products to reduce biodegradation and loss of rheology.

Pyrithione is used in metalworking fluids in selected applications to reduce microbial growth and control odor generation in recirculating systems.
Pyrithione is incorporated into coolant concentrates where broad-spectrum preservation is required under variable water quality.
Pyrithione is used in industrial process waters in selected applications as part of a broader biocide program.

Pyrithione is used in household and institutional cleaners in selected applications to support preservation of water-based formulations.
Pyrithione is incorporated into hard-surface cleaner concentrates where microbial control and storage stability are critical.
Pyrithione is used in specialty disinfectant-adjacent products only where regulatory permissions and labeling requirements are met.

Pyrithione is used in personal care primarily through salt forms, and zinc pyrithione is commonly associated with antidandruff and scalp-care positioning in compatible rinse-off systems.
Pyrithione is incorporated into preservative blends where the pyrithione active contributes broad-spectrum control, subject to regional regulatory limits.
Pyrithione is valued because Pyrithione provides strong antimicrobial performance at low use levels when properly stabilized and matched to formulation pH and compatibility constraints.

Pyrithione is used as a biocidal active in anti-dandruff hair care products when supplied as approved salts in many markets.
Pyrithione supports control of Malassezia-related scalp flaking in some formulations.
Pyrithione helps improve scalp comfort by reducing microbial load in some systems.

Pyrithione is used in shampoos as an antimicrobial active in some product designs.
Pyrithione supports reduction of dandruff symptoms in rinse-off hair care.
Pyrithione helps improve perceived cleanliness and scalp freshness in some shampoos.

Pyrithione is used in hair conditioners and scalp tonics in some markets when permitted in rinse-off formats.
Pyrithione supports antimicrobial control on scalp surfaces in some systems.
Pyrithione helps improve flake reduction routines when used in complete hair care regimens.

Pyrithione is used in body washes and soaps in some formulations as an antimicrobial ingredient where permitted.
Pyrithione supports odor and microbial control in some cleansing products.
Pyrithione helps improve skin freshness perception in some wash-off products.

Pyrithione is used in deodorant and antiperspirant products in some formulations as an antimicrobial active where permitted.
Pyrithione supports reduction of odor-causing bacteria on skin.
Pyrithione helps improve long-lasting odor control in some systems.

Pyrithione is used in topical cosmetic products in some markets as a preservative-like antimicrobial ingredient where allowed.
Pyrithione supports protection of formulations from microbial contamination in some systems.
Pyrithione helps extend shelf life of some water-containing products when compliant with regulations.

Pyrithione is used in industrial preservatives to protect products from microbial growth in some applications.
Pyrithione supports preservation of water-based formulations in industrial settings.
Pyrithione helps reduce spoilage risk in storage tanks and packaged goods in some systems.

Pyrithione is used in paints and coatings as an in-can preservative in some formulations.
Pyrithione supports protection against bacterial and fungal contamination during storage.
Pyrithione helps reduce viscosity loss, odor, and spoilage in some water-based paints.

Pyrithione is used in exterior coatings as a film preservative in some formulations to resist fungal and algal growth.
Pyrithione supports improved appearance retention of coated surfaces.
Pyrithione helps reduce staining and discoloration from microbial growth in some paints.

Pyrithione is used in adhesives and sealants as a preservative in some water-based systems.
Pyrithione supports microbial protection in stored emulsions.
Pyrithione helps reduce product degradation and odor formation in some adhesive products.

Pyrithione is used in latex emulsions and polymer dispersions to protect against contamination in some applications.
Pyrithione supports stable viscosity and performance during storage.
Pyrithione helps reduce microbial spoilage in dispersion manufacturing.

Pyrithione is used in household cleaning products as a preservative active in some formulations.
Pyrithione supports prevention of microbial growth in stored cleaning liquids.
Pyrithione helps maintain product quality over shelf life in some systems.

Pyrithione is used in wet wipes and impregnated materials as a preservative active in some applications where permitted.
Pyrithione supports microbial control in water-rich wipe systems.
Pyrithione helps reduce spoilage risk during storage in some wipes.

Pyrithione is used in textile treatments as an antimicrobial finish in some applications.
Pyrithione supports odor control in treated fabrics in some systems.
Pyrithione helps reduce microbial growth on textiles in humid environments.

Pyrithione is used in leather treatments as an antimicrobial agent in some applications.
Pyrithione supports mold and mildew resistance in treated leather goods.
Pyrithione helps improve storage stability of leather products in humid climates.

Pyrithione is used in plastics as an antimicrobial additive in some formulations.
Pyrithione supports reduction of microbial growth on plastic surfaces in some applications.
Pyrithione helps improve hygiene positioning of some plastic products where allowed.

Pyrithione is used in polymer masterbatches as an antimicrobial active in some manufacturing routes.
Pyrithione supports controlled dosing into finished plastic articles.
Pyrithione helps improve consistency of antimicrobial performance across production.

Pyrithione is used in marine and industrial coatings as a biocide active in some antifouling or anti-slime systems.
Pyrithione supports inhibition of biological growth on submerged or wet surfaces in some applications.
Pyrithione helps reduce biofilm formation that contributes to fouling in some systems.

Pyrithione is used in cooling water systems as a biocide in some industrial programs.
Pyrithione supports control of biofilm and slime in recirculating water systems.
Pyrithione helps improve heat transfer efficiency by reducing biofouling in some operations.

Pyrithione is used in oilfield water systems as a biocide in some applications.
Pyrithione supports control of sulfate-reducing bacteria and biofilms in some systems.
Pyrithione helps reduce corrosion risk linked to microbiologically influenced corrosion in some programs.

Pyrithione is used in metalworking fluids as a preservative/biocide in some formulations.
Pyrithione supports control of bacterial contamination in recirculating coolants.
Pyrithione helps reduce odor and fluid breakdown in some machining operations.

Pyrithione is used in paper and pulp processing as a biocide in some water circuits.
Pyrithione supports control of slime-forming microorganisms in some loops.
Pyrithione helps reduce sheet defects and odor caused by microbial growth in some systems.

Pyrithione is used in building materials as a preservative in some water-based products.
Pyrithione supports microbial stability of construction chemicals during storage.
Pyrithione helps reduce spoilage risk in some liquid admixtures and coatings.

Pyrithione is used in product development to screen antimicrobial efficacy against bacteria and fungi.
Pyrithione supports challenge testing in preserved formulations.
Pyrithione helps optimize dose and compatibility with surfactants and polymers in some systems.

Pyrithione is used in formulation development to balance antimicrobial activity with sensory properties in personal care.
Pyrithione supports optimization of deposition and rinse-off performance in shampoos.
Pyrithione helps improve consumer acceptance while maintaining efficacy in some designs.

Pyrithione is used in manufacturing troubleshooting to address microbial spoilage in water-based products.
Pyrithione supports corrective actions where preservative failure is observed.
Pyrithione helps reduce product returns caused by odor, viscosity loss, and contamination.

Pyrithione is used in quality control to verify active content, stability, and microbiological performance in finished goods.
Pyrithione supports compliance testing for preservative efficacy and dosage control.
Pyrithione helps ensure consistent antimicrobial performance across batches.

Pyrithione is used in education and training as an example of antimicrobial actives used in personal care and industrial preservation.
Pyrithione supports teaching about biocide mechanisms and formulation compatibility.
Pyrithione helps illustrate differences between in-can preservation and dry-film protection.

Pyrithione is used in export products where microbial control is required across long logistics chains.
Pyrithione supports stable shelf life under variable storage conditions when permitted.
Pyrithione helps reduce complaints related to spoilage and microbial growth in stored products.

DESCRIPTION

Pyrithione is a chelating, redox-active antimicrobial that interferes with essential microbial processes, and Pyrithione can disrupt membrane transport and metal homeostasis in sensitive microorganisms.
Pyrithione is typically supplied as a salt because salt forms improve handling, dosing, and stability in aqueous systems, and the selected counterion strongly affects solubility and formulation behavior.
Pyrithione performance depends on pH and ionic environment, and Pyrithione can lose effectiveness or destabilize if the formulation pushes the active out of its stable solubility window.

Pyrithione can interact with surfactants, polymers, and metal ions, and these interactions can change availability of the active and affect clarity, sedimentation, or long-term stability.
Pyrithione is often used as part of a preservation system, and combining Pyrithione with complementary actives can broaden spectrum and improve robustness against challenging contamination profiles.
Pyrithione should be used according to applicable biocide and product regulations for the target market, because permitted uses and concentration limits vary by region and product category.

Pyrithione-containing products should be protected from incompatible materials, and strong oxidizers and certain reactive metals can reduce stability or change performance.
Pyrithione should be stored in tightly closed containers and protected from extreme heat and direct sunlight to maintain consistent active content.
Pyrithione solutions and dispersions should be mixed with controlled shear to avoid destabilizing the formulation and to maintain uniform distribution of the active.

Pyrithione is an organosulfur compound commonly used for antimicrobial activity, most often supplied as salts such as zinc pyrithione or sodium pyrithione.
Pyrithione is typically used at low concentrations because it is an effective antimicrobial active.
Pyrithione is valued for broad-spectrum activity against fungi and bacteria in many preservation and anti-dandruff contexts.

Pyrithione is widely used in personal care products for dandruff control and in industrial products to prevent microbial spoilage.
Pyrithione performance depends on the salt form, particle size or solubility, formulation pH, surfactant system, and deposition behavior.
Pyrithione may be sensitive to certain formulation conditions, so compatibility and stability testing are important.

Pyrithione should be handled and used according to applicable regulations, because permitted uses and limits vary by country and product category.
Pyrithione should be stored in tightly closed containers in a cool, dry place to maintain stability and prevent contamination.
Pyrithione is valued for strong antimicrobial efficacy, broad applicability, and usefulness in both personal care and industrial preservation systems.

PROPERTIES

Common Name: Pyrithione
Chemical Type: Antimicrobial active; antifungal active; biocide (form-dependent)
Appearance: Off-white to yellowish solid (free acid; uncommon as a commercial form) or clear to hazy solution/dispersion (typical commercial forms)
Odor: Mild characteristic odor
Solubility: Form-dependent; free acid has limited solubility; salt forms are more soluble or dispersible depending on counterion
pH Sensitivity: Performance and stability are pH dependent; best window is grade dependent
Metal Interaction: Chelating behavior can influence stability and microbial efficacy
Stability: Stable under recommended storage when properly formulated; avoid strong oxidizers and extreme conditions
Storage Temperature: 5–25°C, tightly closed, protect from light and heat (grade dependent)
Shelf Life: Typically 6–24 months in original sealed packaging (supplier dependent)

FIRST AID

Inhalation:
Move to fresh air if mists or dust are inhaled.
Seek medical attention if respiratory irritation persists.
Avoid breathing aerosols during spraying or high-shear operations that generate mist.

Skin Contact:
Remove contaminated clothing and rinse skin with plenty of water.
Wash thoroughly with soap and water after rinsing.
Seek medical advice if irritation persists or if a rash develops.

Eye Contact:
Rinse cautiously with water for several minutes.
Remove contact lenses if present and easy to do, then continue rinsing.
Seek medical attention promptly if irritation persists.

Ingestion:
Rinse mouth with water and do not induce vomiting.
Seek medical attention if discomfort occurs or if a significant amount is swallowed.
Never give anything by mouth to an unconscious person.

Note to Physicians:
Treat symptomatically.
Consider irritation and potential sensitization depending on exposure route and concentration.
Provide supportive care as needed.

HANDLING AND STORAGE

Handling:
Use appropriate PPE including chemical-resistant gloves and safety glasses.
Avoid skin contact and avoid splashing into eyes during dosing and transfer.
Use closed transfer where possible because biocide concentrates can be hazardous.

Ventilation:
Use general ventilation for normal handling.
Use local exhaust if spraying or mist generation is possible.
Avoid aerosol formation in enclosed spaces without adequate airflow.

Storage:
Store in tightly closed containers in a cool, dry, well-ventilated area.
Protect from direct sunlight, excessive heat, and freezing where applicable to the supplied form.
Keep away from strong oxidizers and incompatible reactive chemicals.

Spill and Leak Procedures:
Contain spill and absorb with inert material for liquids.
Prevent release to drains because aquatic toxicity is a concern for many biocide actives.
Dispose of waste according to local regulations and facility procedures.

Handling Precautions:
Confirm the exact pyrithione form because regulatory status, solubility, and dosing differ for free acid, sodium pyrithione, and zinc pyrithione.
Control formulation pH and compatibility because Pyrithione stability and efficacy depend strongly on the chemical environment.
Rotate stock using FIFO practices to maintain consistent quality and predictable antimicrobial performance.