List of Excipients in Branded Drug SODIUM NITRITE

Company	Tradename	Ingredient	NDC	Excipient	Potential Generic Entry
Hope Pharmaceuticals	SODIUM NITRITE	sodium nitrite	60267-311	NITROGEN	2030-02-10
Hope Pharmaceuticals	SODIUM NITRITE	sodium nitrite	60267-311	WATER	2030-02-10

Sodium Nitrite Excipient Strategy and Commercial Opportunities

Last updated: August 21, 2026

Sodium nitrite is primarily marketed as an active pharmaceutical ingredient in sterile cyanide-antidote injections, not as a conventional excipient. The commercial opportunity is therefore concentrated in formulation simplification, ready-to-administer packaging, stability improvement, emergency-stockpile logistics, and differentiated generic products. The core injectable formulation is technically simple because sodium nitrite is water-soluble and can be supplied in Water for Injection with limited excipient burden.

What is the pharmaceutical role of sodium nitrite?

Sodium nitrite is an approved antidote component for acute cyanide poisoning. It induces methemoglobinemia, allowing methemoglobin to bind cyanide and reduce its interaction with cytochrome oxidase. In the United States, sodium nitrite is administered with sodium thiosulfate under the Nithiodote labeling framework.[1]

The drug is not a typical inactive ingredient. Its pharmacologic activity is central to the product. Excipient strategy concerns the vehicle, pH control, antioxidant or stabilizer selection, preservative exclusion, container closure, and presentation.

Attribute	Sodium nitrite injection
Active ingredient	Sodium nitrite
Typical adult dose	300 mg, equivalent to 10 mL of a 30 mg/mL solution
Route	Intravenous injection
Principal use	Acute cyanide poisoning
Companion antidote	Sodium thiosulfate
Dosage form	Sterile solution for injection
Key regulatory pathway	NDA for innovator products; ANDA for therapeutically equivalent generics
Biosimilar relevance	None
Main formulation constraint	Rapid intravenous administration with control of sterility, particulate matter, concentration, and compatibility

The approved product is administered in a high-acuity setting. Hospitals and emergency responders place greater value on availability, labeling, dosing clarity, and shelf life than on patient convenience.

What excipients are used in sodium nitrite injections?

The most commercially attractive sodium nitrite formulation is a minimal-excipient, preservative-free sterile aqueous solution. The product label identifies sodium nitrite in Water for Injection and does not rely on a complex excipient platform.[1]

Water for Injection

Water for Injection is the principal vehicle. It supports rapid dissolution and avoids excipient-related toxicity during intravenous administration. The formulation must comply with applicable requirements for sterility, bacterial endotoxins, particulate matter, and container closure integrity under FDA regulations and United States Pharmacopeia standards.[2,3]

pH adjustment and buffering

A buffer is not necessarily required if the finished product has an acceptable pH and remains stable throughout its shelf life. Avoiding a buffer can reduce:

• Ionic complexity
• Compatibility risks with sodium thiosulfate
• Precipitation or discoloration risk
• Regulatory burden in a generic product
• Potential impact on intravenous tolerability

A buffer may be considered where stability data show a material benefit. The commercial value of a buffered formulation would depend on a meaningful improvement in shelf life, temperature tolerance, or product robustness.

Preservatives

A preservative-free presentation is preferable for an emergency intravenous antidote. Preservatives can create safety and compatibility concerns, particularly where the product is administered rapidly or to critically ill patients. A single-dose vial or ampoule eliminates the principal commercial rationale for multidose preservation.

Antioxidants and chelating agents

Antioxidants and chelators should not be added without a defined stability problem. Sodium nitrite is an oxidizing nitrite salt, and the use of reducing agents could create chemical incompatibility or alter assay performance. Any stabilizer must be supported by forced-degradation data, impurity profiling, toxicology assessment, and extractables and leachables studies.

Nitrosamine control

Nitrite-containing formulations require a risk-based assessment of nitrosamine formation. The principal concern is exposure to secondary or tertiary amines from excipients, processing aids, elastomer components, adhesives, or packaging materials. FDA guidance requires manufacturers to evaluate nitrosamine risks across drug substances, excipients, manufacturing processes, and packaging systems.[4]

A practical excipient screen should exclude or closely control:

• Amine-containing excipients without a documented need
• Nitrogen-containing processing residues
• Reactive elastomer components
• Packaging materials that can release amines
• Water systems with variable organic contamination

What formulation patents protect sodium nitrite products?

Sodium nitrite has been known for decades, and the active compound is not subject to meaningful composition-of-matter exclusivity in the United States. Commercial protection is more likely to arise from product presentation, combination packaging, manufacturing controls, or emergency-use logistics than from the sodium nitrite molecule itself.

Potential protection area	Commercial relevance	Likely patent strength
Sodium nitrite molecule	Minimal	Very low
Basic aqueous injection	Limited	Low
Sodium nitrite and sodium thiosulfate kit	Moderate	Low to moderate, depending on claims
Dual-chamber or co-packaged presentation	Moderate	Moderate if technically differentiated
Improved stability formulation	Moderate	Moderate if supported by unexpected results
Light-protective packaging	Usually operational rather than patentable	Low
Ready-to-use emergency injector	Potentially high	Moderate to high if device claims are novel
Manufacturing process	Moderate	Moderate if impurity or stability benefits are demonstrated
Hospital stockpile and distribution system	Commercial value, limited patent value	Low

A patent applicant would face difficulty obtaining broad claims covering sodium nitrite in Water for Injection. More defensible claims would need to identify a specific concentration, pH range, impurity profile, container system, stability result, or combination-device configuration.

Method-of-use patents

The principal therapeutic use, treatment of cyanide poisoning, is old and unlikely to support meaningful broad patent exclusivity. Narrower claims could address:

• Weight-based dosing in defined populations
• Sequenced administration with sodium thiosulfate
• Use in a specified exposure setting
• Emergency delivery through a defined device
• Treatment protocols that reduce adverse methemoglobinemia

Such claims would face written-description, obviousness, and enablement challenges if they merely restate established antidote use.

What is the FDA regulatory status of sodium nitrite?

Sodium nitrite injection is regulated as a prescription drug and is used under an NDA-based product framework. Nithiodote is identified in FDA labeling as a cyanide antidote containing sodium nitrite and sodium thiosulfate.[1]

The relevant regulatory issues are:

Regulatory issue	Assessment
FDA status	Approved prescription antidote product
Drug classification	Small-molecule injectable
Generic pathway	ANDA, subject to reference-product and product-specific requirements
Biosimilar pathway	Not applicable
Clinical endpoint	Acute antidote use; efficacy evidence is constrained by the emergency indication
Key CMC controls	Assay, impurities, sterility, endotoxins, particulate matter, pH, container closure, stability
Labeling risk	Medication errors, incorrect sequencing, excessive methemoglobinemia, pediatric dosing
Postmarketing focus	Safety, supply reliability, complaints, and medication-use errors

The FDA-approved label warns that sodium nitrite can cause severe methemoglobinemia, hypotension, and death when used improperly. The risk is especially important in patients with anemia, glucose-6-phosphate dehydrogenase deficiency, compromised oxygen delivery, or concurrent methemoglobin-inducing exposure.[1]

When does sodium nitrite lose exclusivity?

Sodium nitrite does not have meaningful molecule-level exclusivity because the active compound is old. Any remaining commercial exclusivity would arise from product-specific FDA exclusivity, listed patents, regulatory protections, or contractual procurement positions.

The practical exclusivity analysis should separate four categories:

1. Molecule exclusivity: effectively expired.
2. NDA exclusivity: must be confirmed in the current FDA Orange Book and approval history.
3. Patent exclusivity: must be checked against current Orange Book patent listings and litigation records.
4. Commercial exclusivity: may persist through supply contracts, emergency procurement qualifications, stockpile status, or manufacturing capacity.

For a generic entrant, the absence of active composition patents does not eliminate regulatory or commercial barriers. The entrant still must demonstrate pharmaceutical equivalence, bioequivalence where applicable, sterility, stability, container closure integrity, and labeling consistency.

How many patents cover sodium nitrite?

A reliable patent count depends on the search scope. A molecule-only search will produce many historical documents, while a product-specific search should be limited to:

• Sodium nitrite injections
• Sodium nitrite and sodium thiosulfate combinations
• Cyanide antidote kits
• Emergency delivery systems
• Stabilized nitrite solutions
• Manufacturing and packaging claims

Patent families should be screened for legal status, claim scope, continuations, terminal disclaimers, and jurisdiction. Expired historical patents should not be counted as current commercial barriers.

The most relevant U.S. sources are the FDA Orange Book, USPTO Patent Center, FDA Drugs@FDA, and court dockets. The Orange Book lists patents and exclusivity associated with approved listed drugs, but it does not provide a complete global patent landscape.[5]

Are there Paragraph IV challenges to sodium nitrite products?

An ANDA applicant may submit a Paragraph IV certification if it believes a listed patent is invalid, unenforceable, or not infringed. The commercial impact depends on whether the reference product has an active Orange Book patent and whether the patent owner files suit within the statutory period.

For sodium nitrite, Paragraph IV risk is likely to center on:

• Combination-kit claims
• Device claims
• Formulation stability claims
• Container or packaging claims
• Narrow method-of-use patents

A basic sodium nitrite aqueous injection would generally present a lower patent risk than a proprietary injector, dual-chamber system, or stability-enhanced formulation. The regulatory risk may be more significant than the patent risk because injectable products require validated sterile manufacturing and robust stability packages.

What patent litigation affects sodium nitrite?

The central litigation question is whether a current approved reference product has enforceable listed patents. Litigation risk should be assessed through:

• Orange Book patent listings
• FDA paragraph IV notices where publicly available
• District court filings
• ANDA litigation under 35 U.S.C. § 271(e)(2)
• Patent Trial and Appeal Board proceedings
• State procurement and supply disputes

No biosimilar litigation applies because sodium nitrite is a small-molecule drug. A generic dispute would proceed under the Hatch-Waxman framework rather than the Biologics Price Competition and Innovation Act.

What generic entry risks exist for sodium nitrite?

Generic entry is technically feasible but commercially specialized. The market is small, and the product is often purchased for emergency readiness rather than routine dispensing.

Technical barriers

A generic applicant must manage:

• Sterile solution manufacture
• Low particulate burden
• Accurate low-volume withdrawal
• Concentration uniformity
• Light exposure
• Long-term and accelerated stability
• Container closure integrity
• Compatibility with emergency administration equipment
• Labeling and dosing errors

Commercial barriers

The principal business risks are:

• Low and irregular demand
• Emergency stockpile purchasing cycles
• Limited hospital inventory turnover
• Qualification requirements for government procurement
• Product liability exposure
• Supply continuity expectations
• Difficulty achieving manufacturing scale

A low-cost generic can still fail commercially if it lacks reliable supply, adequate shelf life, or a procurement channel.

What commercial opportunities exist for sodium nitrite excipient strategy?

The strongest opportunities are not broad excipient substitution. They are product-system improvements.

Ready-to-use antidote kits

A co-packaged sodium nitrite and sodium thiosulfate kit can reduce preparation time and medication-selection errors. The kit can include separate sterile containers, an administration sequence card, color-coded labels, and weight-based dosing tools.

The commercial value is operational. Patent protection would be stronger if the kit includes a novel delivery architecture rather than merely placing two known vials in a box.

Dual-chamber delivery systems

A dual-chamber syringe or vial could combine the two antidote components immediately before use. This may improve logistics but creates substantial compatibility, stability, extractables, device-validation, and regulatory challenges.

Because sodium nitrite and sodium thiosulfate have different concentrations and administration volumes, a dual-chamber system must preserve dose accuracy and prevent premature interaction.

Light-protective packaging

Amber glass, secondary cartons, foil overwraps, or light-resistant polymer systems can support stability. Packaging improvements may have greater value than new excipients because they preserve a minimal injectable composition.

The strongest commercial claim would be a documented shelf-life extension or improved stability under elevated temperature and emergency transport conditions.

Long-shelf-life stockpile products

Government and institutional stockpiles need products with predictable expiry dating and low replacement frequency. A formulation that supports a longer labeled shelf life, broader temperature excursions, or reduced cold-chain dependence can command procurement preference.

The commercial evidence must include real-time stability, accelerated stability, photostability, container closure testing, and impurity monitoring.

Integrated emergency injectors

An autoinjector or prefilled delivery system could improve speed of administration, but the product would face combination-product regulation and device reliability requirements. The design must address viscosity, dose volume, needle specifications, accidental activation, storage, and emergency user training.

How does sodium nitrite compare with competing cyanide antidotes?

Product or approach	Main active component	Excipient opportunity	Operational profile
Sodium nitrite plus sodium thiosulfate	Nitrite and thiosulfate	Minimal aqueous formulation, kit, device	Established antidote approach with methemoglobinemia risk
Hydroxocobalamin	Hydroxocobalamin	Lyophilized formulation and reconstitution system	Avoids intentional methemoglobinemia but has high acquisition cost and reconstitution burden
Amyl nitrite	Amyl nitrite	Inhalation container and volatility control	Different dosage form and less convenient standardization
Generic sodium nitrite injection	Sodium nitrite	Packaging, shelf life, supply reliability	Lower product differentiation but potentially lower price

Hydroxocobalamin is the main commercial comparator in cyanide antidote procurement. Sodium nitrite products may compete on acquisition cost, compact storage, and established emergency protocols. Hydroxocobalamin may be preferred where methemoglobinemia is considered unacceptable or where rapid single-agent administration is prioritized.[6]

What is the revenue exposure for sodium nitrite products?

Public revenue data are limited because sodium nitrite products are often sold through private hospital, distributor, government, and emergency-preparedness channels. Revenue is driven by procurement contracts rather than chronic prescription volume.

The most important commercial variables are:

• Government stockpile awards
• Hospital emergency department contracts
• Shelf-life and replacement frequency
• Product availability during shortages
• Number of qualified manufacturers
• Kit and device premiums
• International regulatory registrations
• Manufacturing cost per sterile vial

A company entering this market should model revenue by institutional account and contract cycle rather than by retail prescription volume.

What geographic markets offer opportunities?

The United States is the most structured market because FDA approval, Orange Book listings, and government procurement create defined regulatory pathways. Europe, Canada, Australia, and selected Middle Eastern and Asian markets may offer opportunities where cyanide exposure risk is associated with mining, metal processing, chemical manufacturing, or emergency response.

Geographic expansion requires review of:

• Local prescription and hospital-supply rules
• Antidote-stockpile requirements
• Pharmacopoeial standards
• Local language labeling
• Stability zones and transport conditions
• Government tender requirements
• Local manufacturing or supply obligations

A formulation designed for broad temperature storage may have greater value in regions with weak cold-chain infrastructure.

How strong is the sodium nitrite patent estate?

The patent estate is likely weak at the active-ingredient level and potentially moderate for product systems. The strongest defensible positions would involve measurable technical advantages.

IP category	Strength assessment	Best evidence
Sodium nitrite composition	Very weak	Prior-art history
Basic sterile solution	Weak	Limited novelty
Specific impurity control	Moderate	Validated process and stability data
Long-term stability formulation	Moderate	Unexpected shelf-life improvement
Dual-chamber system	Moderate	Device and compatibility data
Prefilled emergency injector	Moderate to strong	Novel device architecture
Kit labeling and workflow	Weak to moderate	Narrow system claims
Manufacturing process	Moderate	Reduced degradation or batch variability

Trade secrets may be more valuable than patents for sterile filling parameters, impurity control, supplier qualification, and packaging selection.

Key Takeaways

• Sodium nitrite is an active antidote ingredient, not a conventional excipient.
• The preferred formulation is a preservative-free sterile aqueous solution with a minimal excipient profile.
• Water for Injection is the central vehicle; unnecessary buffers, antioxidants, chelators, and preservatives increase risk.
• Nitrosamine risk assessment should cover amine-containing excipients, processing materials, elastomers, and packaging.
• Molecule-level patent protection is not a meaningful barrier.
• Product differentiation is more credible through kits, dual-chamber systems, emergency injectors, packaging, and shelf-life improvements.
• Generic entry is technically feasible but commercially constrained by low volume, stockpile procurement, sterility requirements, and supply reliability.
• Hydroxocobalamin is the principal competing cyanide antidote.
• Biosimilar risk is irrelevant because sodium nitrite is a small-molecule injectable.
• Current Orange Book and USPTO records should control any final patent or Paragraph IV decision.

FAQs

Is sodium nitrite itself an excipient?

No. Sodium nitrite is the pharmacologically active ingredient in cyanide-antidote injections. Water for Injection and any pH-adjusting agents are excipients.

Can sodium nitrite be formulated with sodium thiosulfate in one vial?

A single-vial formulation requires compatibility and stability data for both active ingredients. Separate containers or a co-packaged kit are less demanding and are more consistent with established emergency-antidote presentation.

What is the best excipient for improving sodium nitrite stability?

There is no universally preferred stabilizer. A minimal formulation with controlled water quality, suitable container closure, light protection, and validated manufacturing conditions is generally more defensible than adding an excipient without a demonstrated stability benefit.

Does sodium nitrite require a biosimilar application?

No. Sodium nitrite is a small-molecule drug. A competing product would generally use the ANDA pathway if it qualifies as therapeutically equivalent to the reference product.

Can a sodium nitrite kit receive patent protection?

Potentially. Patentability would depend on a novel and non-obvious combination of containers, delivery components, dose sequencing, stability architecture, or emergency-use device functions. A basic package containing two known antidotes would face a weaker patent position.

References

1. U.S. Food and Drug Administration. (2023). Nithiodote (sodium nitrite and sodium thiosulfate) prescribing information. FDA.

2. U.S. Food and Drug Administration. (2024). 21 C.F.R. Part 211: Current good manufacturing practice for finished pharmaceuticals. Electronic Code of Federal Regulations.

3. United States Pharmacopeial Convention. (2024). United States Pharmacopeia and National Formulary. USP.

4. U.S. Food and Drug Administration. (2023). Control of nitrosamine impurities in human drugs: Guidance for industry. FDA.

5. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. FDA Orange Book.

6. U.S. Food and Drug Administration. (2022). Cyanokit (hydroxocobalamin for injection) prescribing information. FDA.