List of Excipients in Branded Drug LYMPHAZURIN

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Company	Tradename	Ingredient	NDC	Excipient	Potential Generic Entry
UNITED STATES SURGICAL CORPORATION	LYMPHAZURIN	isosulfan blue	63261-250	POTASSIUM PHOSPHATE, MONOBASIC
UNITED STATES SURGICAL CORPORATION	LYMPHAZURIN	isosulfan blue	63261-250	SODIUM PHOSPHATE, DIBASIC, ANHYDROUS
UNITED STATES SURGICAL CORPORATION	LYMPHAZURIN	isosulfan blue	63261-250	WATER

Lymphazurin Excipient Strategy and Commercial Opportunities

Last updated: August 26, 2026

Lymphazurin is a sterile, injectable 1% isosulfan blue product used for lymphatic mapping, including sentinel lymph-node identification. Its core drug substance and basic formulation are mature, and meaningful exclusivity is unlikely to remain. Commercial opportunity is concentrated in supply reliability, container-closure performance, ready-to-use presentation, hospital procurement, and differentiated alternatives to methylene blue and indocyanine green. The strongest development path is a robust preservative-free sterile solution with improved packaging, validated cold-chain resilience, and dependable availability.

What is Lymphazurin and how is it used?

Lymphazurin contains isosulfan blue at a concentration of 10 mg/mL. It is administered by injection to identify lymphatic channels and sentinel lymph nodes during surgical procedures. The product is primarily associated with breast cancer and melanoma procedures, although use depends on institutional practice and surgical protocols. [1]

The product is a diagnostic surgical aid rather than a chronic therapeutic medicine. Its demand is therefore linked to procedure volume, hospital formularies, surgical preference, and operating-room availability.

Attribute	Lymphazurin
Active ingredient	Isosulfan blue
Strength	1%, equivalent to 10 mg/mL
Dosage form	Sterile injectable solution
Primary use	Lymphatic mapping and sentinel lymph-node identification
Administration	Local injection near the relevant lymphatic drainage site
Typical commercial format	Single-use vial or ampule presentation
Product category	Small-molecule diagnostic dye
Biosimilar exposure	None
Main competitive products	Methylene blue and indocyanine green-based mapping systems

The principal clinical risk is hypersensitivity, including severe allergic reactions. Product labeling calls for appropriate preparation to manage anaphylaxis and related reactions. [1]

What excipients are used in Lymphazurin?

The labeled formulation uses a simple aqueous vehicle. Public prescribing information identifies sodium chloride and water for injection as inactive ingredients, with hydrochloric acid and sodium hydroxide used for pH adjustment. [1]

Formulation component	Function	Strategic relevance
Water for injection	Sterile vehicle	Supports a simple ready-to-use formulation
Sodium chloride	Tonicity adjustment	Reduces the need for complex excipient systems
Hydrochloric acid	pH adjustment	Supports chemical stability and target pH
Sodium hydroxide	pH adjustment	Supports manufacturing control
Isosulfan blue	Active ingredient	Provides visual lymphatic staining

The formulation does not depend on a complex buffer, surfactant, preservative, co-solvent, or lyophilization cycle. That limits opportunities for conventional excipient-based differentiation but reduces manufacturing complexity and regulatory risk.

Why does the simple excipient system matter commercially?

A simple formulation can reduce:

• Raw-material qualification requirements
• Extractables and leachables concerns
• Sterile filtration complexity
• Compatibility risks with elastomeric closures
• Labeling burden associated with preservatives
• Batch-failure risk caused by multi-component buffer systems

The main technical challenge is not excipient innovation. It is maintaining color intensity, chemical stability, sterility, particulate control, and container compatibility throughout the product shelf life.

What excipient strategy is best for a Lymphazurin product?

The highest-value strategy is a preservative-free, ready-to-use aqueous injection with a tightly controlled pH and osmolality profile.

Recommended formulation platform

A commercially competitive formulation would generally retain:

1. Isosulfan blue at the established 1% concentration.
2. Water for injection as the primary vehicle.
3. Sodium chloride for tonicity.
4. Minimal acid-base adjustment.
5. No antimicrobial preservative unless a specific multidose presentation requires it.

A preservative-free presentation is preferable because the product is used in the operating room and is generally intended for single-patient, single-use administration. It also avoids potential preservative-related irritation, compatibility questions, and additional toxicology work.

Formulation development priorities

Development priority	Commercial purpose
Color stability	Preserves visual identification during surgery
pH control	Limits degradation and batch variability
Low particulate load	Supports injectable-product compliance
Sterile filtration validation	Reduces microbial and endotoxin risk
Light protection	Limits photodegradation risk where relevant
Closure compatibility	Prevents adsorption, extractables, and leakage
Syringe or vial usability	Improves operating-room workflow
Low dead volume	Reduces drug waste and improves dose consistency

The product should be evaluated in glass and polymeric container systems. Blue dyes can interact with packaging components through adsorption, migration, or visual staining. Extractables and leachables testing should cover the selected stopper, syringe barrel, plunger, needle shield, and secondary packaging.

What formulation patents could protect a new Lymphazurin product?

A new isosulfan blue product would face weak protection if it relied only on the active ingredient, 1% concentration, sodium chloride, and water for injection. Those elements are likely vulnerable to obviousness and lack-of-novelty challenges.

Potentially stronger claim categories include:

Container-closure and presentation patents

Protection may be available for:

• A prefilled syringe configured for lymphatic mapping
• A low-dead-volume delivery device
• A light-protective container system
• A container designed to minimize dye adsorption
• A ready-to-use surgical kit combining the dye with mapping accessories
• A closure system with defined extractables and leachables performance

Device and packaging claims must provide a genuine functional advantage. Merely placing a known formulation in a conventional vial would provide limited patent strength.

Stability and manufacturing patents

Potential claim areas include:

• A controlled pH range linked to extended stability
• A defined sterilization or aseptic-processing sequence
• A manufacturing process that reduces particulate formation
• A method for maintaining color intensity after storage
• A formulation with improved stability under temperature excursions
• A process that reduces adsorption to polymeric delivery components

Process claims may provide commercial leverage even when composition claims are weak, but enforcement can be difficult if a competing manufacturer uses a different process.

Combination and workflow patents

Commercially useful claims could cover:

• Isosulfan blue used with a specified imaging system
• A surgical mapping kit containing dye and injection accessories
• A method combining blue-dye mapping with fluorescence imaging
• A procedure-specific dosing or injection protocol

Method-of-use protection may be narrower than a composition patent because hospitals and surgeons can adopt alternative mapping techniques.

When does Lymphazurin lose exclusivity?

Core exclusivity for isosulfan blue and the established Lymphazurin formulation should be treated as expired or commercially weak. The product was approved decades ago, and any original small-molecule patent term would have ended under the standard U.S. patent framework long before the current market period. [1, 2]

Exclusivity category	Assessment
Active-ingredient patent	No meaningful current protection should be assumed
Original formulation patent	Expected to be expired
New formulation patents	Possible only for genuinely differentiated technology
Method-of-use patents	Potentially narrow and procedure-specific
Regulatory exclusivity	No current new-drug exclusivity should be assumed
Biosimilar exclusivity	Not applicable
Generic competition	Legally possible, subject to FDA requirements and commercial economics

The relevant diligence issue is not whether the original product is protected. It is whether any later patent, licensed technology, device claim, or regulatory exclusivity creates a practical barrier to market entry.

What is the Orange Book status of Lymphazurin?

Lymphazurin is an FDA-approved small-molecule injectable product associated with an approved new drug application. The Orange Book remains the relevant U.S. source for listed patents, therapeutic-equivalence evaluations, and application status. [2]

A prospective entrant should distinguish among:

• The reference drug application
• Any approved abbreviated new drug applications
• Patent listings associated with the reference application
• Therapeutic-equivalence codes
• Product discontinuation or marketing-status entries
• FDA requirements for injectable drug-device combinations

An absence of meaningful Orange Book patent listings would make a conventional Paragraph IV strategy less central than for a blockbuster medicine. The competitive question would then shift toward ANDA filing feasibility, sterile injectable manufacturing, and hospital contracting.

Which companies are challenging Lymphazurin exclusivity?

The market is more likely to face product substitution than organized patent litigation. Potential competitors include manufacturers of isosulfan blue generics, suppliers of methylene blue injections, and companies offering indocyanine green or fluorescence-guided surgical systems.

Paragraph IV risk

A generic applicant could challenge listed patents through a Paragraph IV certification if relevant patents were listed in the Orange Book. The practical risk would depend on:

• Whether any unexpired patent is listed
• Whether the patent claims the formulation, use, or device
• Whether the generic product is therapeutically equivalent
• Whether the applicant can match sterile injectable quality attributes
• Whether an ANDA applicant can obtain a reliable supply of isosulfan blue drug substance

For a mature diagnostic dye, regulatory and manufacturing execution may be more important than patent litigation.

Biosimilar risk

Biosimilar risk does not apply. Isosulfan blue is a chemically defined small molecule, not a biologic. Competition would proceed through generic-drug, 505(b)(2), or other applicable small-molecule pathways rather than the biosimilar framework.

What commercial opportunities exist for Lymphazurin?

Reliable sterile-injectable supply

The clearest opportunity is a dependable supply model. Hospitals may maintain a product because surgeons require it for established procedures, even when annual volume is modest. A manufacturer that avoids backorders, communicates allocation clearly, and maintains redundant drug-substance sources can win business without owning strong patents.

Alternative presentations

Commercial differentiation could include:

• Single-dose prefilled syringes
• Smaller-volume vials that reduce wastage
• Unit-of-use surgical kits
• Clearly labeled operating-room cartons
• Tamper-evident packaging
• Light-protective secondary packaging
• Barcoded products compatible with hospital inventory systems

A prefilled syringe could improve workflow but would require comprehensive compatibility, sterility, extractables, dose-delivery, and device validation.

Combination with fluorescence-guided surgery

Indocyanine green and near-infrared imaging are expanding the range of lymphatic mapping technologies. A company could position isosulfan blue as a complementary visual marker rather than a direct substitute. A dual-modality kit could support both conventional visual identification and fluorescence-based imaging, although clinical claims would require appropriate evidence and FDA review.

International supply

Geographic opportunity is strongest where sentinel-node procedures are established but product availability is inconsistent. Market entry would require country-specific review of:

• Isosulfan blue registration status
• Sterile injectable requirements
• Local pharmacopoeial standards
• Import controls
• Hospital tender rules
• Local pharmacovigilance obligations
• Patent and regulatory exclusivity

U.S. approval does not automatically establish commercial rights in Europe, Japan, China, or emerging markets.

How does Lymphazurin compare with methylene blue and indocyanine green?

Attribute	Lymphazurin	Methylene blue	Indocyanine green
Primary signal	Visible blue dye	Visible blue dye	Near-infrared fluorescence
Main use	Lymphatic mapping	Multiple medical uses, including off-label mapping	Fluorescence-guided imaging
Formulation complexity	Low	Low to moderate	Often requires imaging equipment
Equipment requirement	None beyond surgical visualization	None beyond surgical visualization	Near-infrared camera system
Differentiation	Established mapping dye	Lower-cost substitute in some settings	Technology-enabled imaging
Key commercial barrier	Supply and hospital adoption	Substitution and clinical preference	Equipment cost and workflow
Patent opportunity	Packaging, stability, kits	Formulation and delivery	Imaging systems, combinations, workflow

Lymphazurin’s advantage is familiarity and direct visual signaling. Its disadvantage is that it does not provide the technology differentiation of fluorescence-guided systems.

What patent litigation or settlement agreements affect Lymphazurin?

No major, widely recognized patent litigation or settlement framework is central to the Lymphazurin commercial profile. The product’s age and niche procedure volume reduce the likelihood of blockbuster-style litigation.

A transaction involving the product would still require review of:

• Manufacturing and supply agreements
• Drug-substance sourcing rights
• Distribution arrangements
• Trademark ownership
• Product-liability allocation
• Regulatory responsibility
• Hospital group-purchasing contracts
• Any private settlement involving a later entrant

Trademark rights may remain commercially relevant even after composition patents expire. A competing manufacturer generally needs its own product name and cannot rely on Lymphazurin branding.

How strong is the patent estate for Lymphazurin?

The patent estate should be rated weak for the original product and potentially moderate for a technically differentiated successor.

Estate component	Strength
Isosulfan blue composition	Weak or expired
Basic 1% aqueous injection	Weak
Sodium chloride vehicle	Weak
Preservative-free presentation	Low unless tied to unexpected performance
Prefilled syringe	Moderate if device-specific benefits are demonstrated
Stability-control process	Moderate, with narrower enforcement
Surgical kit	Moderate if claims cover a functional workflow
Fluorescence combination	Moderate to strong only with clinical and technical differentiation
Manufacturing know-how	Potentially valuable but confidential rather than patent-based

The strongest defensible assets may be trade secrets, validated manufacturing processes, supplier relationships, regulatory history, and hospital contracts rather than basic formulation patents.

What generic launch scenarios exist for Lymphazurin?

Scenario 1: Conventional sterile injectable entrant

A competitor launches a vial-based 1% isosulfan blue injection. Price competition is likely, but the market may remain concentrated because procedure demand is limited and sterile manufacturing is costly.

Scenario 2: Supply-disruption entry

A new supplier enters during a shortage or allocation event. Hospital conversion can occur quickly, but retention depends on quality consistency and continued availability.

Scenario 3: Device-differentiated entry

A prefilled syringe or unit-dose kit commands a premium by reducing preparation time and medication waste. The product would need evidence that the device improves workflow without introducing dosing or sterility risks.

Scenario 4: 505(b)(2) differentiated product

A sponsor develops a new presentation, concentration, delivery device, or combination product and relies partly on existing safety and efficacy information. The regulatory burden may exceed that of a conventional generic but could support stronger commercial differentiation.

Key Takeaways

• Lymphazurin is a 1% sterile isosulfan blue injection used for lymphatic mapping.
• Its formulation is simple and primarily uses water for injection, sodium chloride, and pH adjusters.
• Original active-ingredient and basic formulation protection should be treated as expired or commercially weak.
• The most credible opportunity is a reliable, preservative-free, ready-to-use sterile injectable.
• Prefilled syringes, unit-dose kits, low-waste packaging, and fluorescence-compatible workflows offer stronger differentiation than new excipients alone.
• Biosimilar risk does not apply because isosulfan blue is a small molecule.
• Generic entry risk is driven mainly by sterile manufacturing, drug-substance supply, regulatory execution, and hospital purchasing.
• Manufacturing know-how, supply reliability, and contracting may be more valuable than composition patents.

FAQs About Lymphazurin Commercialization and Excipient Strategy

Can Lymphazurin be reformulated as a lyophilized product?

A lyophilized product is technically possible, but it would add cycle development, reconstitution steps, packaging requirements, and operating-room complexity. A stable ready-to-use solution is commercially preferable unless solid-state stability provides a clear shelf-life advantage.

Would a preservative improve Lymphazurin’s commercial value?

Usually not for a single-use surgical injection. A preservative could complicate safety, compatibility, and regulatory review. Its value would arise mainly in a validated multidose format.

Can a company patent a new concentration of isosulfan blue?

A concentration claim alone would likely be weak unless linked to an unexpected clinical, stability, dosing, or workflow benefit. A concentration integrated into a specific delivery device or procedure may provide a stronger claim structure.

Is methylene blue a direct generic substitute for Lymphazurin?

It can be a clinical alternative in some settings, but substitution depends on physician preference, institutional protocols, labeling, safety considerations, and the intended procedure. It is not automatically an FDA-approved therapeutic equivalent to Lymphazurin.

What is the best acquisition target in the Lymphazurin market?

The strongest target would likely combine regulatory approval, qualified sterile manufacturing, reliable isosulfan blue sourcing, hospital contracts, and differentiated delivery packaging. A patent portfolio limited to the basic aqueous formulation would provide comparatively little acquisition value.

References

1. U.S. Food and Drug Administration. (n.d.). Lymphazurin 1% injection prescribing information: Isosulfan blue injection.
2. 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