List of Excipients in Branded Drug ISOSULFAN BLUE

Generic Drugs Containing ISOSULFAN BLUE

Company	Ingredient	NDC	Excipient
Eugia US LLC	isosulfan blue	55150-240	POTASSIUM PHOSPHATE, MONOBASIC
Eugia US LLC	isosulfan blue	55150-240	SODIUM PHOSPHATE, DIBASIC, DIHYDRATE
Eugia US LLC	isosulfan blue	55150-240	WATER
Mylan Institutional LLC	isosulfan blue	67457-220	POTASSIUM PHOSPHATE, MONOBASIC
Mylan Institutional LLC	isosulfan blue	67457-220	SODIUM PHOSPHATE, MONOBASIC, MONOHYDRATE
Mylan Institutional LLC	isosulfan blue	67457-220	WATER
Somerset Therapeutics LLC	isosulfan blue	70069-221	POTASSIUM PHOSPHATE, MONOBASIC

What are the Most Frequently-Used Excipients in ISOSULFAN BLUE?

# Of NDCs	Excipient
1	MONOBASIC POTASSIUM PHOSPHATE
6	POTASSIUM PHOSPHATE, MONOBASIC
4	SODIUM PHOSPHATE, DIBASIC, ANHYDROUS
1	SODIUM PHOSPHATE, DIBASIC, DIHYDRATE
2	SODIUM PHOSPHATE, MONOBASIC, MONOHYDRATE
6	WATER

Isosulfan Blue Excipient Strategy and Commercial Opportunities

Last updated: August 6, 2026

Isosulfan blue is a mature, low-volume sterile diagnostic dye used primarily for lymphatic mapping and sentinel lymph-node identification. The commercial opportunity is not a new active-ingredient patent position. It is a manufacturing, presentation, supply-chain, and safety opportunity centered on preservative-free injectable products, ready-to-use delivery systems, and reliable hospital supply.

The reference formulation is a 1% sterile solution containing 10 mg/mL isosulfan blue in water for injection with sodium chloride for isotonicity. The principal product-development risks are anaphylaxis, sterile manufacturing complexity, dye purity, particulate control, container compatibility, and limited procedure-based demand.[1]

What is isosulfan blue used for?

Isosulfan blue is a sulfonated triphenylmethane dye used to visualize lymphatic vessels and assist in the identification of lymph nodes during surgery. Its principal clinical use is lymphatic mapping, including sentinel lymph-node procedures in breast cancer, melanoma, and selected other surgical settings.[1,2]

The product is administered by injection near the relevant tumor or surgical field. Its value is procedural rather than chronic. Hospitals purchase it for operating-room use, and demand depends on surgical volume, clinical protocols, and availability of competing mapping agents.

What is the commercial form of isosulfan blue?

The established commercial form is a sterile injectable solution, commonly described as isosulfan blue injection 1%, equivalent to 10 mg/mL. The product is supplied in a single-dose container and is intended for parenteral use.[1]

Product attribute	Established profile
Active ingredient	Isosulfan blue
Concentration	10 mg/mL, or 1%
Dosage form	Sterile injectable solution
Primary excipients	Sodium chloride and water for injection
Primary use	Lymphatic mapping and sentinel-node identification
Administration	Local injection near the operative site
Preservative strategy	Preservative-free single-dose presentation is commercially appropriate
Commercial setting	Hospital and ambulatory surgical procurement

What excipients are used in isosulfan blue injection?

The reference formulation uses a minimal excipient system. Sodium chloride provides tonicity, while water for injection is the vehicle. Product labeling should be treated as the controlling source for the specific marketed presentation because excipient composition can differ between manufacturers and jurisdictions.[1]

Why is sodium chloride the preferred tonicity agent?

Sodium chloride is commercially attractive because it is familiar to regulators, inexpensive, widely available in injectable grade, and compatible with a low-volume sterile solution. It avoids the additional formulation and regulatory burden associated with phosphate, citrate, acetate, or other buffering systems.

For a locally injected dye, excessive buffering can create unnecessary risks:

• pH-dependent color or solubility changes
• interaction with container materials
• increased ionic strength
• greater injection-site irritation
• additional extractables and leachables considerations
• more complex comparability testing

A sodium-chloride-only approach is therefore strategically strong unless stability studies show a need for pH adjustment.

Does isosulfan blue require a preservative?

A preservative is generally unattractive for this product class. Isosulfan blue is used in a sterile procedural setting and is suitable for a single-dose container. Preservatives could create avoidable concerns involving local tolerability, hypersensitivity, container compatibility, and regulatory justification.

A multi-dose vial would require a stronger commercial case because it would introduce preservative selection, antimicrobial effectiveness testing, in-use stability, withdrawal controls, and greater contamination risk. The preferred strategy is a single-use, preservative-free presentation.

What formulation patents protect isosulfan blue?

Isosulfan blue is a mature active ingredient, and the principal commercial opportunity is unlikely to depend on an unexpired composition-of-matter patent. The relevant intellectual-property assessment should focus on formulation, container, device, manufacturing, and method-of-use claims rather than basic molecule ownership.

Which patent categories could still matter?

A new applicant or product developer should screen the following claim types:

Patent category	Potential relevance
Stable aqueous formulations	Protection for pH, concentration, ionic strength, or specific excipient combinations
Sterile manufacturing	Claims directed to filtration, sterilization, filling, or impurity control
Container systems	Vials, syringes, cartridges, elastomer closures, or light-protective packaging
Delivery devices	Prefilled syringes, applicators, or controlled-volume injection systems
Surgical methods	Claims covering lymphatic mapping or combined use with another imaging agent
Combination products	Isosulfan blue used with radiocolloid, fluorescence imaging, or surgical navigation
Packaging	Light-protective or oxygen-reduced packaging intended to preserve dye quality

An excipient combination by itself may have weak patent value if the composition merely substitutes routine injectable excipients. Stronger protection would require demonstrated technical effects, such as materially improved stability, reduced degradation products, reduced adsorption, improved syringe compatibility, or better clinical handling.

How strong is the patent estate for isosulfan blue?

The patent estate is likely weak for the basic active ingredient and stronger only for narrowly defined product improvements. The most defensible commercial position would combine a formulation patent with manufacturing know-how and a differentiated delivery presentation.

What would make an isosulfan blue formulation patent stronger?

A stronger application would include:

1. Comparative stability data against the established sodium-chloride formulation.
2. Defined limits for dye-related impurities and degradation products.
3. Container-closure compatibility data.
4. Protection against oxidation, light exposure, adsorption, or precipitation.
5. A reproducible sterile manufacturing process.
6. Evidence that the formulation improves shelf life, shipping robustness, or clinical workflow.

A claim directed only to "isosulfan blue in water for injection with sodium chloride" would face substantial obviousness and lack-of-novelty risks if the composition is already disclosed in labeling or prior art.

What FDA regulatory pathway applies to isosulfan blue?

A new isosulfan blue injectable would generally be regulated as a prescription drug requiring an FDA application. The relevant pathway depends on the reference product, regulatory designation, product availability, and whether the proposed product is therapeutically equivalent to an approved product.

Is an ANDA possible?

An abbreviated new drug application may be available when the applicant can demonstrate pharmaceutical equivalence and bioequivalence or otherwise satisfy the FDA requirements for the product. For an injectable dye administered locally during surgery, the development program may require careful attention to:

• Active ingredient identity and strength
• Sterility and bacterial endotoxins
• Particulate matter
• Extractable volume
• Container-closure integrity
• Color and appearance
• Impurity profile
• pH and osmolality
• Stability under light and temperature stress
• Comparative labeling
• Drug-device compatibility, if a prefilled system is used

The practical regulatory path should be confirmed against the FDA’s current product-specific guidance, reference-listed-drug status, and application history.[3,4]

What is the Orange Book status of isosulfan blue?

The Orange Book is the relevant source for determining whether a specific isosulfan blue reference product has listed patents, exclusivity, therapeutic-equivalence codes, or an active reference-listed-drug designation.[3]

A commercial assessment should distinguish among:

• An approved product that remains the reference product
• An approved product that has been discontinued
• A product with no active patent listing
• A product with regulatory exclusivity but no patent protection
• A product with an ANDA pathway constrained by reference-product availability

Because isosulfan blue is an old, small-market injectable, regulatory and supply conditions may be more important than patent exclusivity. FDA Drug Shortages data and the Orange Book should be reviewed together when evaluating entry timing.[3,5]

When does isosulfan blue lose exclusivity?

The basic molecular and formulation exclusivity for isosulfan blue is expected to be expired or commercially irrelevant. The principal entry barriers are likely to be regulatory approval, sterile manufacturing, product availability, clinical adoption, and procurement relationships.

For an existing product, the relevant timeline is:

Exclusivity issue	Commercial assessment
Composition-of-matter patent	Not expected to be the principal barrier
Basic formulation patent	Likely expired or limited in scope
New formulation patent	Possible for a differentiated product
Method-of-use patent	Possible but likely narrow and procedure-specific
FDA exclusivity	Must be checked against current Orange Book records
Trade secrets	Potentially meaningful for impurity control and manufacturing
Supply contracts	May affect hospital access without creating legal exclusivity

What excipient strategy offers the best commercial opportunity?

The strongest strategy is a simple, preservative-free, ready-to-use sterile solution with a differentiated presentation.

Strategy 1: Single-dose prefilled syringe

A prefilled syringe could reduce operating-room preparation, minimize dosing errors, and improve handling. The development program would need to address:

• Syringe material compatibility
• Dye adsorption to the barrel or stopper
• Silicone oil interaction
• Needle and closure compatibility
• Extractables and leachables
• Light protection
• Dose accuracy
• Sterility through shelf life

A prefilled syringe may command a price premium if it reduces preparation time and waste. The market is small, so the device cost must remain proportionate to procedure volume.

Strategy 2: Unit-dose vial with improved packaging

A lower-risk approach is a conventional single-dose vial with optimized packaging. Opportunity areas include:

• Light-resistant secondary packaging
• Terminal sterilization, if compatible with dye stability
• Low-particulate elastomer closures
• Improved labeling for operating-room identification
• Carton configurations aligned with surgical case volume

This strategy has lower device complexity than a prefilled syringe and may be more suitable for generic or contract-manufactured entry.

Strategy 3: Lyophilized product

A lyophilized isosulfan blue product could improve long-term stability if the aqueous formulation has degradation or shipping limitations. It would require a reconstitution step and would add:

• Bulking agents
• Cryo- or lyoprotectants
• Residual moisture control
• Cake appearance requirements
• Reconstitution-time specifications
• Additional operating-room handling

Lyophilization is commercially attractive only if it produces a clear stability, supply, or geographic-distribution advantage. It is not automatically superior to a stable aqueous injection.

Strategy 4: Buffered or antioxidant-containing formulation

A buffer or antioxidant could be justified if studies show improved color stability or reduced degradation. The formulation should avoid unnecessary excipients because each added component creates new regulatory and compatibility requirements.

Potential candidates may include conventional injectable buffers or stabilizers, but selection should be driven by forced-degradation and container-closure data rather than by excipient novelty alone. The strongest patent position would require a measurable, unexpected improvement.

What manufacturing and IP barriers affect commercial entry?

The major barriers are technical and operational.

Sterile manufacturing barriers

Isosulfan blue injection requires validated control of:

• Bioburden and endotoxins
• Sterile filtration or sterilization
• Dye uniformity
• Fill-volume accuracy
• Visible and subvisible particles
• Container-closure integrity
• Batch-to-batch color consistency
• Impurity and degradation profiles

Dye products can create visual inspection and cleaning challenges in aseptic facilities. Residual color in equipment or filling lines can complicate changeover and validation.

Supply-chain barriers

The market may depend on a limited number of qualified suppliers for pharmaceutical-grade isosulfan blue. Supply continuity should be assessed across:

• Active-ingredient manufacturing
• Regional API qualification
• Sterile fill-finish capacity
• Primary packaging
• Redundant testing laboratories
• Hospital distribution channels

A reliable supply position can be commercially valuable even without patent exclusivity, particularly when hospitals experience shortages or procedure cancellations.

Which companies are challenging or competing with isosulfan blue?

Competition comes from both alternative dyes and non-dye mapping technologies. The principal alternatives include:

Alternative	Competitive effect
Patent blue V	Similar blue-dye lymphatic mapping use in some markets
Methylene blue	Lower-cost alternative but with different safety and clinical handling considerations
Indocyanine green	Near-infrared fluorescence mapping using compatible imaging systems
Technetium-99m radiocolloid	Established radiolabeled sentinel-node mapping method
Combined radiocolloid and fluorescence protocols	May reduce reliance on a single blue dye
Magnetic or other navigation agents	Emerging alternatives in selected surgical settings

Indocyanine green is the most important technology substitute where hospitals have near-infrared imaging infrastructure. Isosulfan blue retains value where surgeons need a visible dye, where equipment access is limited, or where clinical protocols use combined mapping.

What litigation affects isosulfan blue?

No major active patent dispute should be assumed solely from the existence of an older isosulfan blue product. A current freedom-to-operate review should examine:

• Orange Book patent listings
• ANDA litigation records
• Federal district court dockets
• Patent Trial and Appeal Board proceedings
• Device patents covering prefilled delivery systems
• Method patents covering combined imaging procedures

For a new formulation, litigation risk is more likely to arise from device or formulation claims than from the expired active ingredient. A Paragraph IV certification would become relevant only if an ANDA applicant were required to address an unexpired listed patent associated with the reference product.[3,6]

What licensing deals could create value?

Licensing opportunities are more likely to involve delivery systems, manufacturing technology, or clinical workflow than the isosulfan blue molecule itself.

Potential deal structures include:

• Licensing a prefilled-syringe platform
• Acquiring sterile fill-finish capacity
• Partnering with a surgical imaging company
• Co-marketing with a radiocolloid supplier
• Licensing a light-protective container system
• Contracting with a regional distributor serving hospitals
• Combining isosulfan blue with a surgical navigation platform

A product paired with an imaging device could command a higher commercial value, but the arrangement may create combination-product, reimbursement, training, and capital-equipment dependencies.

What revenue exposure and market size should investors expect?

Public company disclosures generally do not isolate isosulfan blue revenue. The product is a niche hospital injectable, and its sales are linked to procedure volume rather than recurring prescriptions.

Revenue exposure is driven by:

• Sentinel-node procedure volume
• Number of hospitals using visible blue dye
• Product availability
• Competing fluorescence systems
• Contract pricing
• Surgical seasonality
• Shortage-driven substitution
• Geographic approvals and distribution

The commercial ceiling is limited compared with oncology therapeutics, but a dependable supplier can achieve attractive niche economics through manufacturing efficiency, low competition, and hospital formulary access. The most promising business model is a focused sterile-injectable portfolio rather than a standalone high-investment platform based solely on isosulfan blue.

How does isosulfan blue compare with indocyanine green?

Factor	Isosulfan blue	Indocyanine green
Visualization	Visible blue dye	Near-infrared fluorescence
Equipment requirement	Low	Requires compatible imaging system
Formulation	Ready-to-use sterile injection commonly used	Often requires reconstitution or specific preparation
Patent opportunity	Limited for basic product; possible for presentation	More active opportunities around formulations, imaging, and devices
Hospital capital burden	Low	Higher where imaging equipment is required
Clinical workflow	Familiar surgical dye	Integrated with fluorescence-guided surgery
Commercial growth	Stable niche or supply-driven	Linked to adoption of fluorescence imaging

The two products can be complementary rather than purely substitutive. A hospital may use both, depending on procedure, equipment, surgeon preference, and institutional protocol.

Key Takeaways

• Isosulfan blue is a mature, low-volume sterile injectable used mainly for lymphatic mapping.
• The established excipient strategy is minimal: sodium chloride for tonicity and water for injection.
• A preservative-free, single-dose product is commercially preferable to a multi-dose formulation.
• The strongest near-term opportunity is a ready-to-use prefilled syringe or improved unit-dose vial.
• Basic composition-of-matter and conventional formulation patent protection are unlikely to create meaningful exclusivity.
• New patents would need to cover a specific technical advantage, such as improved stability, reduced adsorption, container compatibility, or delivery-device performance.
• Regulatory approval, sterile manufacturing, supply reliability, and hospital procurement are more important than patent expiry.
• Indocyanine green and fluorescence-guided surgery are the most relevant technology substitutes.
• Licensing value is concentrated in delivery systems, sterile manufacturing, imaging partnerships, and distribution rather than in the active ingredient.
• A focused product can be commercially attractive as part of a broader sterile injectable or surgical-imaging portfolio.

FAQs About Isosulfan Blue Excipient and Commercial Strategy

Can isosulfan blue be formulated without sodium chloride?

Yes. Alternative tonicity systems may be technically possible, but sodium chloride is the established and commercially efficient choice. Any replacement would require comparative stability, osmolality, tolerability, and regulatory justification.

Is a prefilled syringe patentable for isosulfan blue?

Potentially. Patentability would depend on the specific syringe construction, formulation-device interaction, stability benefit, dosing configuration, or manufacturing process. A generic prefilled presentation without a technical distinction would face substantial patentability risk.

Can isosulfan blue be supplied in a multidose vial?

It may be technically possible, but a multidose product would require preservative justification, antimicrobial effectiveness testing, in-use stability, and contamination controls. A single-dose presentation is generally better aligned with surgical use.

Does isosulfan blue compete with radiocolloid mapping?

Yes. Radiocolloid mapping is an established alternative, and some institutions use combined radiocolloid and blue-dye procedures. Isosulfan blue remains useful where visible dye confirmation is clinically preferred.

What is the best geographic expansion strategy for isosulfan blue?

The strongest targets are jurisdictions with established sentinel-node surgery, limited access to fluorescence imaging, and hospital demand for visible surgical dyes. Expansion requires separate review of product registration, colorant controls, sterile injectable requirements, and local procurement channels.

References

1. U.S. Food and Drug Administration. (n.d.). Isosulfan blue injection prescribing information. FDA labeling database.

2. National Cancer Institute. (n.d.). Isosulfan blue. NCI Drug Dictionary.

3. U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations. FDA Orange Book.

4. U.S. Food and Drug Administration. (n.d.). Inactive ingredient database. FDA.

5. U.S. Food and Drug Administration. (n.d.). Drug shortages database. FDA.

6. U.S. Food and Drug Administration. (n.d.). ANDA litigation and patent certification resources. FDA.