Drugs Containing Excipient (Inactive Ingredient) SODIUM THIOSULFATE ANHYDROUS

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Branded drugs containing SODIUM THIOSULFATE ANHYDROUS excipient, and estimated key patent expiration / generic entry dates

Company	Tradename	Ingredient	NDC	Excipient	Potential Generic Entry
Anbex Inc	IOSAT	potassium iodide	51803-001	SODIUM THIOSULFATE ANHYDROUS
Anbex Inc	IOSAT	potassium iodide	51803-002	SODIUM THIOSULFATE ANHYDROUS

Generic drugs containing SODIUM THIOSULFATE ANHYDROUS excipient

Company	Ingredient	NDC	Excipient
Anbex Inc	potassium iodide	51803-001	SODIUM THIOSULFATE ANHYDROUS
Anbex Inc	potassium iodide	51803-002	SODIUM THIOSULFATE ANHYDROUS

Sodium Thiosulfate Anhydrous Pharmaceutical Excipient Market Dynamics and Financial Trajectory

Last updated: August 19, 2026

Sodium thiosulfate anhydrous is a niche pharmaceutical-grade inorganic salt with low unit economics but strategically important applications in drug formulation, antidote products, and specialized hospital therapies. Its financial trajectory is driven less by broad excipient consumption than by demand for high-purity sodium thiosulfate drug products, including sodium thiosulfate injection and pediatric cisplatin-otoprotection therapy.

Public companies and suppliers generally do not report sodium thiosulfate anhydrous revenue separately. Standalone market-size estimates therefore lack financial transparency. The most defensible view is a modest-volume, fragmented specialty-chemical market with stable baseline demand, limited differentiation at commodity quality, and higher margins for validated pharmaceutical-grade material.

What is sodium thiosulfate anhydrous used for in pharmaceuticals?

Sodium thiosulfate anhydrous, CAS Registry Number 7772-98-7, is the water-free form of sodium thiosulfate. It is used as an active pharmaceutical ingredient, formulation ingredient, reducing agent, complexing agent, and stabilizer depending on the product and regulatory filing.

Key pharmaceutical applications include:

Application	Role of sodium thiosulfate	Commercial significance
Cyanide poisoning treatment	Sulfur donor that supports conversion of cyanide to thiocyanate	Hospital and emergency-use demand
Cisplatin otoprotection	Active ingredient in sodium thiosulfate injection products	Specialty oncology demand
Pharmaceutical formulations	Reducing or antioxidant function in selected products	Small-volume excipient demand
Topical and dermatological products	Active or functional ingredient in selected formulations	Limited, product-specific demand
Analytical and manufacturing processes	Reducing agent and process reagent	More industrial than pharmaceutical

Sodium thiosulfate is often supplied as the pentahydrate rather than the anhydrous form. This distinction matters because the two forms have different molecular weights, water content, stability profiles, storage requirements, and assay calculations. Pharmaceutical buyers typically qualify the specific form used in the approved formulation rather than treating anhydrous and pentahydrate material as interchangeable.

How large is the sodium thiosulfate anhydrous excipient market?

No audited public source reports a standalone global market value for sodium thiosulfate anhydrous used as a pharmaceutical excipient. Supplier revenues are usually aggregated across sodium thiosulfate grades, industrial photography, water treatment, mining, textile, medical, and laboratory markets.

The pharmaceutical excipient segment is likely small relative to total sodium thiosulfate consumption. Several factors constrain its size:

1. Sodium thiosulfate is a mature inorganic chemical with broad industrial supply.
2. Pharmaceutical formulations use relatively small quantities compared with water treatment and industrial applications.
3. Many drug products use sodium thiosulfate as an active ingredient rather than as a conventional excipient.
4. The anhydrous form competes with the more widely traded pentahydrate.
5. Buyers generally qualify material for a defined manufacturing process and do not maintain large inventories.

The market is therefore better analyzed through supplier qualification, drug-product demand, and pricing spread than through a conventional high-growth excipient model.

What drives demand for pharmaceutical-grade sodium thiosulfate?

Demand from sodium thiosulfate drug products

The most important pharmaceutical demand driver is approved sodium thiosulfate therapy. In September 2022, the U.S. Food and Drug Administration approved PEDMARK, a sodium thiosulfate injection developed by Fennec Pharmaceuticals, to reduce the risk of cisplatin-associated ototoxicity in pediatric patients one month of age and older with localized, nonmetastatic solid tumors.[1]

PEDMARK is a drug product, not merely an excipient application. Its commercial performance can increase demand for pharmaceutical-grade sodium thiosulfate, but the active ingredient requirement is product-specific and does not translate directly into a broad excipient market expansion.

Sodium thiosulfate is also used in cyanide antidote products. The FDA label for sodium thiosulfate injection identifies the product for treatment of acute cyanide poisoning, generally in combination with sodium nitrite under applicable clinical conditions.[2]

Demand from formulation functionality

As an excipient or functional formulation ingredient, sodium thiosulfate can provide reducing activity and protect against oxidative degradation. These applications are narrower than mainstream excipient categories such as microcrystalline cellulose, lactose, povidone, polyethylene glycol, and sodium chloride.

Demand depends on:

• Compatibility with the active ingredient
• pH and ionic-strength requirements
• Oxidation sensitivity of the formulation
• Sterilization method
• Container-closure system
• Stability data and regulatory precedent
• Availability of compendial or equivalent quality documentation

A formulation change from sodium thiosulfate to another antioxidant or reducing agent can remove demand from a specific product. Conversely, once an approved product uses sodium thiosulfate, replacement requires regulatory assessment, comparability work, and stability testing.

What is the financial trajectory for sodium thiosulfate anhydrous?

The financial trajectory is likely to be stable rather than high-growth. Revenue growth depends on a combination of volume, pharmaceutical-grade pricing, and new drug-product adoption.

Financial factor	Directional effect	Assessment
Industrial sodium thiosulfate prices	Downward pressure on base pricing	Large nonpharmaceutical supply base
Pharmaceutical qualification	Supports price premium	Documentation and validation create switching costs
New sodium thiosulfate drug approvals	Positive volume effect	Most material upside driver
Pentahydrate substitution	Limits anhydrous growth	Formulation and process compatibility determine substitution
Energy and sulfur costs	Variable cost pressure	Affects manufacturing and purification
Freight and packaging	Higher impact on small shipments	Pharmaceutical orders may be relatively small
Supplier concentration	Can support pricing	Depends on regional availability and quality status
Regulatory changes	Potentially positive or negative	New uses expand demand; stricter controls raise costs

The product has a low intrinsic material value relative to the cost of pharmaceutical qualification. This creates a two-tier market:

• Commodity or technical-grade sodium thiosulfate, where price and availability dominate.
• Pharmaceutical-grade material, where compliance, batch consistency, traceability, impurity control, and supply continuity determine the commercial value.

A supplier with an approved customer file, validated manufacturing process, and reliable change-control system can earn a premium without owning a strong compound patent.

Which companies supply pharmaceutical-grade sodium thiosulfate?

The supply base includes specialty pharmaceutical excipient distributors, inorganic chemical manufacturers, and companies producing sodium thiosulfate for medical or laboratory use. Public disclosure rarely identifies the final supplier used by a branded drug manufacturer.

Competitive differentiation generally rests on:

• USP-NF, Ph. Eur., BP, or equivalent compliance
• GMP manufacturing
• Elemental impurity control
• Low bioburden or sterile-manufacturing capability where required
• Residual solvent and moisture control
• Lot-to-lot assay consistency
• Regulatory support packages
• Dual-site or contingency supply
• Packaging suitable for hygroscopic or moisture-sensitive material

The leading commercial risk is not necessarily a lack of raw material. It is the loss of a qualified source. A drug manufacturer may face substantial requalification work if a supplier changes the crystallization, drying, packaging, or impurity profile of the material.

How does anhydrous sodium thiosulfate compare with the pentahydrate?

Attribute	Anhydrous sodium thiosulfate	Sodium thiosulfate pentahydrate
Chemical form	Water-free salt	Five-water crystalline hydrate
CAS number	7772-98-7	10102-17-7
Molecular weight	Approximately 158.11 g/mol	Approximately 248.18 g/mol
Water content	Low by definition, subject to specification	Structural water is present
Manufacturing	Requires controlled dehydration and moisture protection	Crystallization and hydrate control are central
Formulation benefit	Higher active-equivalent content per unit mass	Often easier to crystallize and commercially source
Main risk	Moisture uptake or rehydration	Water-content variability and hydrate conversion
Substitution status	Requires formulation and regulatory evaluation	Not automatically interchangeable

The anhydrous form delivers more sodium thiosulfate equivalent per gram. That advantage can reduce shipping mass and improve dosing efficiency, but it does not guarantee lower total product cost. Drying, moisture control, packaging, and specification management can offset the material-efficiency benefit.

What FDA regulatory status applies to sodium thiosulfate?

Sodium thiosulfate has established pharmaceutical use in the United States, but regulatory status depends on the product and intended function.

Active pharmaceutical ingredient status

Sodium thiosulfate injection is an approved drug product for cyanide poisoning. PEDMARK is an approved sodium thiosulfate product for pediatric cisplatin-associated ototoxicity risk reduction.[1][2]

Excipient status

An excipient use must be supported by the specific formulation, route, dosage form, concentration, and regulatory precedent. The FDA Inactive Ingredient Database provides product-specific precedent for inactive ingredients, but database inclusion does not create a general approval for every route or concentration.[3]

A pharmaceutical buyer should distinguish:

• FDA-approved active ingredient use
• Inactive ingredient precedent
• Compendial status
• Supplier GMP status
• Drug-master-file support
• Finished-product route and dosage-form requirements

Sodium thiosulfate used in an injectable product faces substantially higher quality and control requirements than material used in a nonsterile oral or topical formulation.

What patent protection covers sodium thiosulfate products?

Sodium thiosulfate itself is an old chemical compound and is unlikely to support meaningful new-compound exclusivity. Commercial protection is more likely to arise from:

• A specific medical use
• A pediatric oncology indication
• A dosing schedule
• A formulation concentration
• A sterile injectable presentation
• Container-closure or delivery technology
• Manufacturing or purification methods
• Combination therapy with another agent

The relevant patent estate for a sodium thiosulfate drug product must be assessed separately from the excipient molecule. FDA Orange Book listings, approved-label information, patent-use codes, and litigation records are product-specific.[4]

For PEDMARK and other sodium thiosulfate products, the principal commercial barrier is likely to be regulatory and clinical differentiation rather than ownership of the underlying sodium thiosulfate molecule. A generic or competing product would need to address formulation, manufacturing, labeling, clinical-use, and patent risks.

What generic entry risks exist for sodium thiosulfate drug products?

Generic entry risk varies by product.

For a conventional sodium thiosulfate injection used in cyanide poisoning, the active ingredient is established and the technical barrier may be moderate. The principal barriers are sterile manufacturing, supply reliability, regulatory approval, institutional contracting, and product economics.

For pediatric cisplatin otoprotection, entry risk is higher because the product may depend on:

• A defined pediatric indication
• Specific timing relative to cisplatin administration
• Dosing by body surface area or weight
• Clinical evidence concerning tumor outcomes
• Labeling restrictions
• Method-of-use patents
• Hospital and oncology-center adoption
• Reimbursement and treatment protocols

Paragraph IV challenges are possible where listed patents cover an approved sodium thiosulfate product. No standalone Paragraph IV risk should be inferred from the existence of sodium thiosulfate as an old compound. The relevant analysis must identify current Orange Book listings and the product-specific Abbreviated New Drug Application pathway.

How strong is the pharmaceutical patent estate?

The underlying chemical patent estate is weak because sodium thiosulfate has long-standing industrial and medical use. The stronger protection opportunities are downstream.

Protection category	Likely strength
Sodium thiosulfate composition of matter	Very weak or unavailable
Purified pharmaceutical-grade material	Moderate only if tied to defined specifications or process claims
New formulation	Moderate, depending on novelty and clinical relevance
Sterile injectable product	Moderate, but vulnerable to design-around
Pediatric cisplatin otoprotection method	Potentially stronger if supported by clinical evidence
Manufacturing process	Variable; depends on impurity and crystal-form differentiation
Trade secrets and supplier qualification	Commercially meaningful but not patent exclusivity

Trade secrets, customer qualification, and regulatory documentation may protect supplier economics longer than patents. These barriers can support recurring sales even when the chemical itself is broadly available.

What are the geographic market dynamics?

North America and Europe provide the highest value for pharmaceutical-grade sodium thiosulfate because of stringent GMP, pharmacopoeial, and regulatory requirements. Asia remains important for manufacturing capacity, raw materials, and cost-efficient production.

Geographic risks include:

• Dependence on a single manufacturing country
• Import controls and customs delays
• Different pharmacopoeial specifications
• Regional GMP inspection outcomes
• Limited local inventory for emergency-use products
• Currency and freight volatility
• Registration requirements for drug substances and excipients

Hospitals may maintain sodium thiosulfate inventory for emergency treatment, creating a demand pattern that is less predictable than chronic-use excipients. Oncology demand is more forecastable but depends on treatment volumes, label adoption, and reimbursement.

What is the outlook for revenue and investment?

The base case is low-to-moderate revenue growth with periodic volume increases tied to approved sodium thiosulfate therapies. Margin expansion is more likely at the pharmaceutical-grade supplier level than at the bulk chemical level.

Base case

Demand remains stable. Existing antidote and formulation uses continue, while PEDMARK-related demand contributes incremental volume. Pricing remains competitive because technical-grade supply is available.

Upside case

Additional clinical adoption of sodium thiosulfate in oncology, emergency medicine, or other specialized indications increases pharmaceutical-grade consumption. New formulations use the anhydrous form to improve concentration, reduce water-related instability, or simplify logistics.

Downside case

Drug-product adoption remains narrow, manufacturers use the pentahydrate form, or alternative antioxidants and antidotes replace sodium thiosulfate in selected applications. Commodity oversupply compresses pricing.

The most attractive commercial position is not necessarily bulk sodium thiosulfate production. It is qualified pharmaceutical supply with regulatory support, dual sourcing, controlled moisture specifications, and access to finished-dose manufacturers.

Key Takeaways

• Sodium thiosulfate anhydrous is a niche pharmaceutical-grade material, not a high-volume mainstream excipient.
• Public financial data does not isolate pharmaceutical excipient revenue for this compound.
• The largest value driver is demand for approved sodium thiosulfate drug products, especially pediatric cisplatin otoprotection and cyanide antidote therapy.
• The pentahydrate is a major competing form and may limit anhydrous adoption.
• Compound-level patent protection is weak; downstream use, formulation, manufacturing, and regulatory barriers are more relevant.
• Pharmaceutical-grade suppliers can earn premiums through GMP compliance, documentation, moisture control, and supply reliability.
• The likely financial trajectory is stable with episodic upside from new drug approvals and broader clinical adoption.
• Generic entry risk is product-specific and depends on Orange Book listings, formulation design, sterile manufacturing, and method-of-use protection.

FAQs

Is sodium thiosulfate anhydrous a high-growth pharmaceutical excipient?

No. It is a specialized, low-volume excipient and active pharmaceutical ingredient. Growth depends mainly on approved drug products and specialized clinical use rather than broad excipient substitution.

Can sodium thiosulfate pentahydrate replace the anhydrous form?

Not automatically. The hydrate state changes molecular weight, water content, assay calculations, stability, and processing behavior. A substitution generally requires formulation, manufacturing, and regulatory evaluation.

Does sodium thiosulfate have biosimilar risk?

No. Biosimilar regulation applies to biological products. Sodium thiosulfate is a small-molecule inorganic compound. Competitive risk arises from generic drug applications and alternative formulations, not biosimilars.

Is sodium thiosulfate listed in the FDA Orange Book?

Approved sodium thiosulfate drug products may have Orange Book entries and listed patents, depending on the product. The chemical ingredient itself is not the relevant unit of Orange Book analysis.

What is the main investment risk in pharmaceutical sodium thiosulfate?

The main risk is limited addressable volume. A supplier may qualify material for a valuable drug product but still face modest total demand, pentahydrate substitution, commodity pricing pressure, and dependence on a small number of customers.

References

1. U.S. Food and Drug Administration. (2022). FDA approves sodium thiosulfate to reduce the risk of ototoxicity associated with cisplatin in pediatric patients. https://www.fda.gov
2. U.S. Food and Drug Administration. (n.d.). Sodium thiosulfate injection prescribing information. https://www.accessdata.fda.gov
3. U.S. Food and Drug Administration. (n.d.). Inactive Ingredient Database. https://www.accessdata.fda.gov/scripts/cder/iig/index.cfm
4. U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations, Orange Book. https://www.fda.gov/drugs/drug-approvals-and-databases/approved-drug-products-therapeutic-equivalence-evaluations-orange-book