List of Excipients in Branded Drug PENTETATE CALCIUM TRISODIUM

Company	Tradename	Ingredient	NDC	Excipient	Potential Generic Entry
hameln pharma gmbh	PENTETATE CALCIUM TRISODIUM	pentetate calcium trisodium	70651-001	CALCIUM CARBONATE
hameln pharma gmbh	PENTETATE CALCIUM TRISODIUM	pentetate calcium trisodium	70651-001	SODIUM HYDROXIDE
hameln pharma gmbh	PENTETATE CALCIUM TRISODIUM	pentetate calcium trisodium	70651-001	WATER

Pentetate Calcium Trisodium Excipient Strategy and Commercial Opportunities

Last updated: August 7, 2026

Pentetate calcium trisodium, also known as calcium-DTPA or Ca-DTPA, is an injectable decorporation agent used to remove plutonium, americium, and curium from the body after internal contamination. Its commercial value is driven less by routine prescription demand than by government stockpiling, radiological emergency preparedness, specialty hospital use, and supply-security requirements. The strongest product strategy is a low-excipient, preservative-free sterile injection with validated metal-ion control, long shelf life, and reliable procurement capacity.

What is pentetate calcium trisodium used for?

Pentetate calcium trisodium is a chelating agent indicated for decorporation of plutonium, americium, or curium following known or suspected internal contamination. It is administered intravenously or by nebulization in selected circumstances. The calcium form is generally preferred for the initial treatment period, while zinc-DTPA may be used for subsequent treatment because it reduces the risk of zinc depletion associated with repeated calcium-DTPA administration.[1]

Ca-DTPA is not a conventional high-volume pharmaceutical product. Demand is episodic and concentrated among:

• National and regional emergency stockpiles
• Military and civil-defense organizations
• Nuclear power operators
• Radiological laboratories
• Hospitals with nuclear medicine or radiation-oncology capabilities
• Government procurement agencies
• Occupational health programs serving radiation workers

The product’s value proposition is availability during a low-probability, high-consequence event.

What is the preferred excipient strategy for calcium-DTPA injection?

The preferred formulation is a simple, aqueous, preservative-free parenteral solution. A minimal excipient system reduces toxicological burden, simplifies regulatory review, and limits interactions with the chelating active ingredient.

Core formulation architecture

Component	Strategic function	Commercial relevance
Pentetate calcium trisodium	Active chelating ingredient	Requires tight assay and impurity control
Water for Injection	Vehicle	Standard for intravenous products
Hydrochloric acid and/or sodium hydroxide	pH adjustment	Supports solubility, stability, and tolerability
Nitrogen overlay, if justified	Oxygen reduction	May support stability during storage
Preservative	Generally undesirable	Avoid in single-dose emergency injections unless required

The formulation should avoid excipients that can introduce competing metal ions or form complexes with DTPA. Calcium, zinc, magnesium, iron, copper, aluminum, and other trace metals may affect active-ingredient composition, assay, impurity profiles, or long-term stability. Raw materials and manufacturing equipment therefore require an elemental impurity strategy specifically adapted to a strong chelator.

A simple formulation also supports emergency use. It reduces the number of administration decisions, decreases compatibility concerns, and improves the feasibility of long-duration stockpiling.

What pH and packaging controls matter for Ca-DTPA?

The target pH should be based on the reference product, clinical tolerability, active-ingredient stability, and container compatibility. A commercially viable product should maintain a controlled pH range across shelf life rather than rely on a broad adjustment window.

Critical quality attributes include:

• Appearance and absence of visible particles
• Assay of pentetate calcium trisodium
• Related substances and degradation products
• pH
• Osmolality
• Sterility
• Bacterial endotoxins
• Extractable and leachable metals
• Container-closure integrity
• Subvisible particles
• Delivered volume
• Stability under intended storage and shipping conditions

A low-metal manufacturing environment is particularly important. Stainless-steel contact surfaces, water systems, elastomer closures, glass components, and processing aids can contribute trace elements. The sponsor should establish a metal-ion control plan covering raw materials, equipment, filling lines, and packaging.

Container and closure options

A single-dose glass vial is the conventional commercial configuration for a low-demand injectable. It offers a familiar regulatory pathway and strong compatibility history. Polymer containers may reduce breakage and improve logistics but create a larger extractables and leachables program.

An attractive commercial format is a ready-to-use single-dose vial with:

• No reconstitution step
• Clear labeling for Ca-DTPA versus Zn-DTPA
• A tamper-evident closure
• A compact carton suitable for stockpile rotation
• Barcoding compatible with government inventory systems
• Shelf-life monitoring through lot-level traceability

A prefilled syringe could improve deployment speed but would require additional evaluation of syringe materials, lubrication, silicone oil, plunger compatibility, extractables, and long-term stability. It is less likely to be the first commercial configuration unless the sponsor has a clear emergency-use or field-administration advantage.

What excipients should be avoided in pentetate calcium trisodium?

The formulation should avoid unnecessary buffers and multifunctional excipient systems. Phosphate, citrate, acetate, or other polyfunctional anions can alter metal-ion equilibria and complicate the chemistry of a highly effective chelator. Any buffer system would require evidence that it does not change the calcium-DTPA complex, generate precipitation, or affect clinical performance.

Preservatives are generally unattractive for a single-dose injectable. Benzyl alcohol, phenol, parabens, and related agents add toxicity, labeling, and compatibility issues without a clear commercial benefit when the product is packaged as a single-dose vial.

The sponsor should also avoid:

• Excipients containing residual metals
• Chelating or complexing additives
• Unnecessary surfactants
• High ionic-strength systems
• Latex-containing administration components
• Novel excipients without a clear performance benefit
• Colorants that could obscure precipitation or particulate matter

The main excipient opportunity is therefore optimization, not diversification. A differentiated product should be easier to manufacture, store, inspect, and administer rather than chemically more elaborate.

What formulation patents protect pentetate calcium trisodium?

Pentetate calcium trisodium is an old active pharmaceutical ingredient, and the core composition-of-matter opportunity is likely exhausted. Commercial protection is more likely to arise from formulation, container, manufacturing, delivery, or emergency-use features than from the molecule itself.

Potentially protectable subject matter includes:

• A defined pH and concentration range
• A low-metal manufacturing process
• A formulation with specified impurity limits
• A long-term stable aqueous solution
• A particular vial or syringe configuration
• A nebulized dosage form
• A dual-product kit containing Ca-DTPA and Zn-DTPA
• A method that sequences calcium-DTPA and zinc-DTPA treatment
• A field-deployable administration system
• A packaging design that improves stockpile shelf-life management

Patentability would depend on unexpected stability, improved safety, reduced degradation, enhanced usability, or a measurable manufacturing advantage. Broad claims covering an aqueous Ca-DTPA injection are likely to face novelty and obviousness challenges because the active ingredient and conventional parenteral approach are longstanding.

When does pentetate calcium trisodium lose exclusivity?

The active ingredient has no meaningful modern composition-of-matter exclusivity. The relevant commercial barriers are regulatory approval, manufacturing qualification, procurement contracts, quality history, and government purchasing rather than patent duration.

Exclusivity and patent position

Protection category	Likely relevance to Ca-DTPA
Composition-of-matter patent	No practical modern opportunity
New chemical entity exclusivity	Not applicable to an old chelator
Pediatric exclusivity	No clear commercial relevance
Orphan-drug exclusivity	Possible only if a qualifying designation and approval were obtained
Formulation patent	Possible but narrow
Method-of-use patent	Possible for specific treatment protocols
Manufacturing patent	Possible for impurity or stability improvements
Trade secret	Important for low-metal process control and supply qualification
Government procurement protection	Commercially significant, but not patent exclusivity

A company entering this market should not assume that absence of a blocking patent guarantees rapid sales. The more important barriers may be a small qualified supplier base, limited active-ingredient capacity, government purchasing cycles, and the cost of maintaining validated sterile manufacturing for low annual volumes.

What is the FDA regulatory status of Ca-DTPA?

The FDA recognizes calcium-DTPA and zinc-DTPA as decorporation therapies for specific internal contamination scenarios. The approved labeling describes use for plutonium, americium, and curium contamination and includes dosing and administration information for adults and pediatric patients.[1]

A new sponsor would need to determine whether its product can proceed through an abbreviated pathway based on an approved reference product or whether a 505(b)(2) application is more appropriate. The pathway will depend on the availability and suitability of a reference-listed drug, the degree of formulation and presentation similarity, and the proposed labeling.

Key regulatory issues include:

• Demonstration of pharmaceutical equivalence
• Sterility and container-closure validation
• Stability data supporting the proposed shelf life
• Control of elemental impurities
• In vitro or clinical bridging, depending on the pathway
• Labeling consistency with the approved decorporation indication
• Manufacturing inspection readiness
• Pharmacovigilance for electrolyte and trace-metal effects

Because Ca-DTPA is used in specialized emergencies, regulatory value may be enhanced by government preparedness programs, priority review mechanisms, or medical countermeasure procurement initiatives when applicable. Those programs do not eliminate the need for product quality and manufacturing evidence.

What is the Orange Book status of pentetate calcium trisodium?

The Orange Book analysis should focus on the specific approved product, application number, listed patents, and exclusivity entries rather than the active ingredient alone. The existence of an approved Ca-DTPA product does not establish that all formulations or presentations are unprotected.

For a prospective entrant, the key diligence questions are:

1. Whether the reference product is listed as a prescription drug product.
2. Whether any patents are listed for the approved formulation, container, or method of use.
3. Whether any regulatory exclusivity remains active.
4. Whether an ANDA or 505(b)(2) applicant would need a Paragraph IV certification.
5. Whether the proposed label would include protected method-of-use language.

A Paragraph IV challenge would have limited commercial value unless the challenged patent covers a commercially important product attribute. If the originator’s protection is limited to a narrow formulation or treatment method, a carve-out strategy may be possible, subject to FDA approval and infringement risk.

Which companies are challenging Ca-DTPA patents?

There is no established high-volume generic litigation pattern comparable to major oncology, diabetes, or immunology products. The market is small, and public litigation activity is likely to be limited. The principal competitive risk is entry by a qualified sterile-injectable manufacturer rather than a large wave of ANDA filers.

A challenger would typically evaluate:

• Whether the reference product has active Orange Book patents
• Whether the proposed product can avoid the protected formulation
• Whether the sponsor can obtain sufficient active-ingredient supply
• Whether government contracts require a specific presentation
• Whether the product can meet stockpile shelf-life requirements
• Whether a separate zinc-DTPA product is needed for a complete portfolio

The commercial advantage of a first credible alternative may be greater than the advantage of a late entrant with a lower list price.

What manufacturing and intellectual-property barriers affect Ca-DTPA?

The most defensible know-how is likely to sit in manufacturing and quality control. DTPA products require careful management of trace metals because the active ingredient is designed to bind metals. This creates a formulation and process-control challenge that is unusual for ordinary sterile injectables.

Potential barriers include:

• Consistent high-purity Ca-DTPA supply
• Control of calcium-to-DTPA stoichiometry
• Prevention of metal contamination
• Long-term pH stability
• Low particulate levels
• Robust sterilization or aseptic processing
• Container-closure compatibility
• Validation of extended storage
• Lot release testing for emergency stockpile deployment

A company with an established sterile injectable plant and strong elemental-impurity controls may have a meaningful advantage over a virtual pharmaceutical company. The product does not require complex drug-delivery technology, but it does require disciplined chemistry and quality systems.

What commercial opportunities exist for Ca-DTPA?

Government stockpiles and medical countermeasures

Government procurement is the largest identifiable commercial opportunity. Buyers value availability, shelf life, domestic or diversified supply, rapid replenishment, and predictable pricing. A supplier may obtain revenue through:

• Initial stockpile contracts
• Shelf-life extension programs
• Rotational replacement of expiring inventory
• Surge-capacity agreements
• Regional emergency-preparedness contracts
• Framework agreements with public hospitals

Stockpile products generate irregular revenue. The supplier must manage inventory carrying costs and avoid dependence on a single procurement cycle.

Ca-DTPA and Zn-DTPA portfolio sales

A dual-product portfolio is commercially stronger than a single Ca-DTPA product. Calcium-DTPA is used for initial treatment, while zinc-DTPA may be selected for subsequent therapy. Offering both products can simplify procurement and allow buyers to maintain a complete treatment protocol.

A portfolio could include:

• Ca-DTPA single-dose injection
• Zn-DTPA single-dose injection
• Treatment kits with protocol labeling
• Hospital emergency cartons
• Replacement inventory programs
• Training materials for pharmacy and radiation-safety personnel

Delivery-system differentiation

Nebulized administration may create a separate opportunity for inhalation delivery in selected contamination situations. The product would require dedicated development of aerosol performance, device compatibility, dose delivery, microbial control, and labeling. This is a higher-risk opportunity than a conventional vial but could provide stronger differentiation.

International markets

International demand is concentrated in countries with nuclear power, radiological research, military preparedness, or centralized emergency-medicine procurement. Geographic expansion requires assessment of:

• Local registration requirements
• Government tender rules
• Language-specific emergency labeling
• Shelf-life expectations
• Import controls
• Local pharmacopoeial standards
• Cold-chain or ambient-storage requirements

The best markets are likely to be those with centralized procurement and established radiation emergency plans.

How strong is the patent estate for pentetate calcium trisodium?

The patent estate is likely weak at the molecule level and potentially moderate for carefully defined product or process improvements. A new entrant should rely on regulatory execution, manufacturing reliability, and procurement access rather than broad patent exclusivity.

Estate component	Commercial strength
Active ingredient	Low
Basic aqueous injection	Low
Narrow pH or concentration claims	Low to moderate
Low-metal manufacturing process	Moderate if technically distinctive
Long-term stability claims	Moderate if supported by unexpected data
Nebulized delivery	Moderate to potentially strong
Kit and emergency packaging	Low to moderate
Trade secrets and quality systems	Moderate
Government supply contracts	High for contract duration, but not permanent

The most valuable protection may be a combination of process know-how, validated shelf life, regulatory history, and customer qualification. Those assets are difficult for an entrant to reproduce quickly even when patent barriers are limited.

What generic launch risks exist for Ca-DTPA?

A generic or follow-on launch could occur in several forms:

Launch scenario	Likely timing	Commercial effect
Conventional sterile vial	Dependent on regulatory approval and procurement	Price competition and dual sourcing
Ca-DTPA plus Zn-DTPA portfolio	Longer development cycle	Stronger government and hospital positioning
Extended-shelf-life product	Dependent on stability package	Potential stockpile advantage
Prefilled syringe	Longer device and stability program	Faster deployment but higher cost
Nebulized product	Separate development and regulatory burden	Differentiated administration option
Regional private-label supply	Shorter commercial cycle after approval	Limited volume, tender-driven pricing

The principal risk is not immediate erosion of a large outpatient market. It is displacement from a government contract, hospital system, or national stockpile that values supply redundancy. A lower-cost entrant may also pressure incumbent pricing during contract renewals.

What licensing deals could create value?

Licensing opportunities are more likely to involve manufacturing and distribution than novel pharmacology. Potential structures include:

• Supply and distribution agreements with government-contract specialists
• Regional licensing to sterile-injectable companies
• Co-development of Ca-DTPA and Zn-DTPA presentations
• Contract manufacturing with an established parenteral facility
• Device licensing for nebulized delivery
• Shelf-life extension and stockpile-management agreements
• Technology transfer for low-metal processing

A commercially attractive deal would combine validated manufacturing with access to procurement channels. A license limited to patent rights without supply capability would have less value in this market.

Key Takeaways

• Pentetate calcium trisodium is a specialized radiological emergency injectable, not a routine high-volume prescription product.
• The strongest formulation strategy is a preservative-free aqueous solution with minimal excipients.
• Water for Injection and pH adjustment agents are the likely core inactive components; unnecessary buffers, preservatives, and metal-containing excipients should be avoided.
• Trace-metal control is a central manufacturing and stability issue.
• Composition-of-matter exclusivity is not a realistic commercial strategy for this old chelator.
• Formulation, manufacturing, nebulization, packaging, and treatment-kit patents may provide narrower protection.
• The principal revenue opportunity is government and institutional stockpiling, supported by shelf-life management and reliable supply.
• A Ca-DTPA and Zn-DTPA portfolio is commercially stronger than Ca-DTPA alone.
• Regulatory execution, sterile manufacturing capacity, procurement qualification, and inventory reliability are more important than broad patent ownership.
• The most credible differentiated product is a ready-to-use, long-shelf-life, low-metal, single-dose injectable with robust emergency labeling.

FAQs

Is calcium-DTPA the same as zinc-DTPA?

No. Both are DTPA chelates, but calcium-DTPA is generally used for initial treatment after plutonium, americium, or curium contamination, while zinc-DTPA is often used for subsequent treatment to reduce zinc depletion risk.[1]

Can calcium-DTPA be formulated with a preservative?

It can be evaluated, but a preservative-free single-dose vial is generally the stronger commercial design. Preservatives add toxicological, compatibility, and labeling complexity without a clear benefit for emergency injectable use.

Does Ca-DTPA require cold-chain distribution?

The storage requirement depends on the approved product and stability data. A supplier that supports controlled room-temperature storage and extended shelf life may have a material advantage in stockpile logistics.

Is a nebulized calcium-DTPA product commercially feasible?

It is technically feasible but requires a separate development program covering aerosol performance, device compatibility, delivered dose, sterility, and clinical labeling. It offers more differentiation than a conventional vial but carries greater regulatory and manufacturing complexity.

What is the most valuable patent opportunity for a new Ca-DTPA manufacturer?

A narrowly drafted patent covering an unexpected stability benefit, low-metal manufacturing process, specialized delivery device, or stockpile-ready product configuration is more credible than a broad patent on the active ingredient or basic aqueous injection.

References

1. U.S. Food and Drug Administration. (n.d.). Pentetate calcium trisodium injection prescribing information. FDA.
2. U.S. Food and Drug Administration. (n.d.). Pentetate zinc trisodium injection prescribing information. FDA.
3. U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations. FDA.
4. U.S. Food and Drug Administration. (n.d.). Medical countermeasures for radiological and nuclear threats. FDA.
5. U.S. Pharmacopeial Convention. (2024). United States Pharmacopeia and National Formulary. USP.