List of Excipients in Branded Drug PROLASTIN-C LIQUID

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Prolastin-C Liquid Excipient Strategy and Commercial Opportunities

Last updated: August 23, 2026

Prolastin-C Liquid is a ready-to-use, plasma-derived alpha1-proteinase inhibitor for intravenous augmentation therapy in adults with severe hereditary alpha1-antitrypsin deficiency and emphysema. Its commercial value is driven less by excipient exclusivity than by protein-stability performance, container compatibility, cold-chain control, manufacturing know-how, supply reliability, and the clinical and operational advantages of a liquid presentation over a reconstituted product.[1]

What is Prolastin-C Liquid?

Prolastin-C Liquid contains alpha1-proteinase inhibitor [human], also known as alpha1-antitrypsin or A1PI. Grifols manufactures and markets the product in the United States.[1]

Attribute	Prolastin-C Liquid
Active ingredient	Alpha1-proteinase inhibitor [human]
Source	Human plasma
Therapeutic category	Alpha1-antitrypsin replacement therapy
Administration	Intravenous infusion
Strength	1,000 mg per 20 mL, equivalent to 50 mg/mL
Dose	60 mg/kg once weekly
Dosage form	Sterile liquid solution
Route	Intravenous
Storage	Refrigerated; do not freeze
Preservative status	Preservative-free
Primary manufacturer	Grifols
Regulatory pathway	Biologic license application
Primary commercial protection	Biologic manufacturing, regulatory approval, product know-how and supply infrastructure

The liquid product eliminates the reconstitution step required for earlier lyophilized presentations. That change can reduce preparation time, handling steps and potential reconstitution errors in infusion centers and home-infusion settings.[1]

What excipients are used in Prolastin-C Liquid?

The formulation uses a relatively limited excipient system designed to maintain protein stability and tonicity without introducing preservatives. The FDA prescribing information identifies sodium phosphate and sodium chloride among the product components, with water for injection as the vehicle.[1]

Excipient or formulation component	Primary role	Commercial relevance
Sodium phosphate	Buffering and pH control	Helps maintain protein stability during storage
Sodium chloride	Tonicity adjustment	Supports compatibility with intravenous administration
Water for injection	Aqueous vehicle	Enables ready-to-use liquid presentation
No antimicrobial preservative	Avoids preservative exposure	Supports single-use sterile presentation

The product labeling should control any final excipient assessment because formulation details may vary by presentation, manufacturing revision or market. The key commercial point is that Prolastin-C Liquid relies on a low-complexity, parenteral excipient system rather than a differentiated excipient platform.

Why does the excipient system matter for A1PI?

Alpha1-proteinase inhibitor is a plasma-derived protein. Its formulation must limit aggregation, loss of activity, precipitation, adsorption to process surfaces and degradation during refrigerated storage. Excipient selection also affects:

• Protein recovery during filling and transfer
• Particle formation
• Subvisible particulate levels
• Container closure compatibility
• Infusion-site tolerability
• Shelf-life validation
• Cold-chain excursion performance
• Batch release specifications

For a protein replacement therapy, excipients are part of a larger control strategy. The formulation cannot be assessed separately from purification, viral inactivation, sterile filtration, filling, container selection and storage conditions.

How does Prolastin-C Liquid compare with lyophilized Prolastin-C?

The principal product distinction is presentation. Prolastin-C Liquid is supplied as a ready-to-use solution, while lyophilized products require reconstitution before infusion.

Commercial factor	Prolastin-C Liquid	Lyophilized Prolastin-C
Preparation	Ready to use	Requires reconstitution
Water for reconstitution	Not separately required at point of use	Required
Handling time	Lower	Higher
Reconstitution risk	Lower	Higher
Excipient development burden	Liquid stability and container compatibility	Lyophilization cycle and cake reconstitution
Packaging burden	Liquid vial or container system	Powder vial plus diluent
Cold-chain exposure	Continuous refrigerated liquid storage	Refrigerated storage of powder and diluent
Differentiation	Workflow convenience	Potentially greater solid-state stability
Infusion-center positioning	Strong	Less convenient
Home-infusion positioning	Stronger operational fit	More preparation steps

The liquid presentation can support premium pricing or retention even when the active ingredient is the same. The commercial argument depends on measurable reductions in preparation time, nursing labor, inventory complexity and administration errors.

What excipient strategy supports commercial differentiation?

The highest-value strategy is not simply to add more excipients. It is to preserve the current low-excipient profile while improving usability, stability and manufacturing economics.

1. Optimize protein stability without adding unnecessary formulation complexity

Potential development objectives include:

• Extending refrigerated shelf life
• Increasing tolerance to short temperature excursions
• Reducing aggregation and particle formation
• Preserving elastase-inhibitory activity
• Reducing adsorption to vial and tubing surfaces
• Improving recovery after dilution or transfer

A simple formulation can be commercially useful because every added excipient creates new analytical, toxicological, regulatory and supply-chain requirements.

2. Evaluate surfactant strategies cautiously

A low-level nonionic surfactant may reduce interfacial stress during filling, shipping and infusion preparation. The opportunity is technically plausible but must be balanced against:

• Oxidative degradation
• Peroxide impurities
• Protein modification
• Extractables and leachables
• New analytical release tests
• Regulatory comparability requirements

A surfactant-based reformulation would have the strongest value if it materially improves shipping robustness or shelf life. It would have weaker value if it only changes the inactive-ingredient list without improving product performance.

3. Develop low-volume and high-concentration options

The current 50 mg/mL presentation requires a substantial infusion volume for weight-based dosing. A higher-concentration product could reduce:

• Infusion duration
• Number of vials
• Packaging waste
• Pharmacy preparation time
• Shipment volume
• Home-infusion burden

The technical constraint is protein concentration. Higher concentration can increase viscosity, aggregation risk, opalescence and manufacturing losses. A successful high-concentration product could create meaningful lifecycle value, but it would require extensive comparability and stability work.

4. Improve compatibility with infusion devices

A formulation and container program can target compatibility with:

• Standard infusion bags
• Syringes
• Transfer devices
• Needleless connectors
• In-line filters
• Home-infusion pumps
• Automated compounding systems

This work can produce practical differentiation even without a new excipient. Device compatibility data can support institutional adoption and reduce objections from specialty pharmacies and infusion providers.

What formulation patents could protect Prolastin-C Liquid?

Formulation patent value would depend on claim scope and public patent records. Potential claim categories include:

1. A1PI compositions with defined pH and ionic strength.
2. Protein concentrations within a specified range.
3. Low-aggregate or low-particulate formulations.
4. Liquid compositions with defined refrigerated stability.
5. Formulations containing selected surfactants, sugars, amino acids or polyols.
6. Container closure systems that limit protein adsorption.
7. Methods for stabilizing A1PI during filling, shipping or administration.
8. Combination claims covering the formulation and infusion device.
9. Manufacturing processes that produce defined purity or activity profiles.
10. Use claims tied to a specific dosing regimen or patient population.

A formulation patent is strongest when it claims a measurable technical effect, such as improved potency retention, reduced aggregation or extended shelf life. Broad claims covering routine buffers or isotonic agents are more vulnerable to written-description, enablement and obviousness challenges.

Is Prolastin-C Liquid protected by Orange Book patents?

No conventional Orange Book analysis should be assumed for Prolastin-C Liquid. It is a biologic product regulated under a biologics license application, not a conventional small-molecule drug approved under a new drug application. The Orange Book primarily records approved drug products and patent information submitted for NDA products.[2]

Relevant exclusivity and patent analysis should instead consider:

• The Purple Book
• The biologics license application
• FDA approval records
• Public patent databases
• Patent assignments
• Patent term adjustment
• Patent term extension
• Pediatric exclusivity
• State and federal litigation records
• Biosimilar approval and interchangeability activity

The absence of an Orange Book listing does not mean the product lacks intellectual-property protection. It changes the pathway for follow-on competition and patent notice analysis.

When does Prolastin-C Liquid lose exclusivity?

The product does not have a single, publicly determinative small-molecule patent cliff. Commercial protection may come from several overlapping sources:

Protection layer	Relevance to Prolastin-C Liquid
BLA approval	Establishes the approved biologic product
Reference-product exclusivity	Can delay biosimilar approval under the Public Health Service Act
Formulation patents	May protect liquid composition and stability characteristics
Process patents	May protect purification, viral safety or filling processes
Device patents	May protect delivery or container systems
Trade secrets	May protect plasma pooling, purification and process controls
Manufacturing capacity	Can delay practical competition even after legal barriers expire
Supply contracts	Can strengthen market retention

For biologics, the federal reference-product exclusivity period is generally 12 years from first licensure, subject to statutory rules and regulatory interpretation.[3] That period must be distinguished from patent expiration. A patent may expire before or after regulatory exclusivity, and a biosimilar applicant may challenge relevant patents through the Biologics Price Competition and Innovation Act process.

What biosimilar risk exists for Prolastin-C Liquid?

Biosimilar risk is currently more limited than generic risk because alpha1-proteinase inhibitor is a complex plasma-derived protein with demanding comparability requirements. A biosimilar applicant would need to establish a high degree of similarity in areas including:

• Primary amino acid sequence
• Protein structure
• Glycosylation
• Purity
• Aggregates and particles
• Biological activity
• Pharmacokinetics
• Immunogenicity
• Viral safety
• Manufacturing consistency

A biosimilar does not need to use the same excipients as the reference product. That creates a commercial opening for alternative formulations, but the applicant must demonstrate that formulation differences do not affect safety, purity or potency.

What is the risk from plasma-derived competitors?

Plasma-derived competition may be more immediate than biosimilar competition. Competitors can seek approval for their own alpha1-proteinase inhibitor products using independent plasma collection, fractionation, purification and viral-clearance systems. Their commercial advantages may include:

• Larger plasma supply
• Lower manufacturing cost
• Broader distribution
• Better payer contracts
• More convenient packaging
• Extended dating
• Lower infusion volume

The principal barrier is not only formulation. It is access to qualified plasma, validated manufacturing and a scalable regulatory-quality system.

Which commercial opportunities exist for excipient innovation?

Higher-concentration Prolastin-C Liquid

A more concentrated formulation could reduce vial count and administration volume. The opportunity is strongest for larger patients, high-volume infusion centers and home-infusion providers. The principal development risks are viscosity, aggregation and loss of activity.

Longer room-temperature excursion allowance

A formulation that tolerates defined short-term excursions could reduce product waste and simplify home delivery. This opportunity has direct economic value because specialty biologics face shipment delays, refrigerator failures and patient scheduling changes.

Extended shelf life

A longer dating period could reduce inventory write-offs and improve distribution across specialty pharmacies. Shelf-life claims must be supported by real-time and accelerated stability data, including potency, purity, aggregation and particulate testing.

Smaller and more flexible vial sizes

Alternative vial sizes could improve dose rounding and reduce unused product. A 500-mg presentation could be useful for smaller patients, while a larger presentation could reduce vial count for high-weight patients. The commercial case depends on manufacturing cost, demand segmentation and reimbursement policy.

Home-infusion compatibility

A formulation optimized for home use could reduce the need for hospital-based administration. Relevant attributes include:

• Fewer preparation steps
• Lower infusion volume
• Reliable short-term temperature tolerance
• Clear visual inspection
• Compatible transfer and infusion devices
• Simple disposal requirements

Combination product opportunities

A prefilled syringe, cartridge or closed-system transfer presentation could create additional differentiation. The technical burden would include container closure integrity, device performance, dose accuracy, extractables and leachables, and human-factors validation.

What manufacturing and IP barriers protect the product?

The most defensible barriers are likely to be manufacturing and quality-related rather than excipient-related.

Plasma supply

Alpha1-proteinase inhibitor products depend on human plasma collection and testing. Supply constraints can affect batch volume, cost of goods and launch scalability. A competitor with a reliable plasma network may gain an advantage even if its formulation is similar.

Viral safety

The manufacturing process must control known and emerging pathogens through donor screening, testing and validated viral-reduction steps. These process controls are difficult to replicate quickly and can create regulatory barriers for new entrants.

Protein recovery

A1PI recovery from plasma requires efficient fractionation and purification. Small changes in process yield can materially affect cost of goods because the active ingredient is derived from a biological raw material.

Aggregation and particulate control

The liquid formulation must control particles across bulk processing, filling, storage and administration. This requires process engineering, container selection and extensive analytical control.

Cold-chain distribution

Refrigerated logistics create operating costs and supply risks. A competitor with more temperature-tolerant product could gain an advantage without changing the therapeutic molecule.

What litigation and Paragraph IV risks affect Prolastin-C Liquid?

Paragraph IV litigation is primarily associated with ANDA products and therefore is not the default framework for this biologic. Follow-on competition would more likely involve:

• A biosimilar application
• Patent disputes under the BPCIA
• Declaratory-judgment litigation
• Patent-infringement actions involving formulation or process claims
• Trade-secret disputes involving manufacturing methods
• Regulatory disputes over interchangeability or labeling

A patent review should identify Grifols entities, current assignees, continuations, terminal disclaimers, maintenance fees, prosecution history and claim scope. Without a current patent-family review, a reliable list of Prolastin-C Liquid patent numbers and expiration dates cannot be stated.

How strong is the Prolastin-C Liquid patent estate?

The product’s practical protection is likely stronger than an excipient-only analysis suggests. A robust estate would combine:

• Composition claims
• Liquid-stability claims
• Manufacturing claims
• Purification claims
• Viral-clearance claims
• Container and device claims
• Method-of-use claims

The strongest claims would cover a formulation or process that produces a demonstrated technical advantage and cannot be readily designed around. The weakest claims would cover conventional phosphate-buffered saline-type formulations without a narrowly defined performance benefit.

From a commercial perspective, trade secrets and manufacturing scale may be as important as issued patents. A biosimilar developer can often avoid a formulation patent by using a different buffer system, concentration or container. It cannot easily avoid the need for qualified plasma, validated viral safety and reproducible protein manufacturing.

How does Prolastin-C Liquid compare with competing A1PI products?

The competitive set includes other alpha1-proteinase inhibitor products, including Glassia, Aralast NP and Zemaira, subject to current market availability and jurisdiction.[4-6]

Product	Active ingredient	Presentation emphasis	Key competitive variable
Prolastin-C Liquid	Alpha1-proteinase inhibitor [human]	Ready-to-use liquid	Established brand, liquid convenience and distribution
Glassia	Alpha1-proteinase inhibitor [human]	Liquid	Infusion workflow and product availability
Aralast NP	Alpha1-proteinase inhibitor [human]	Powder for reconstitution	Reconstitution burden versus product access
Zemaira	Alpha1-proteinase inhibitor [human]	Powder for reconstitution	Established manufacturing and prescriber familiarity

The most important differentiators are product availability, payer coverage, infusion burden, vial count, home-infusion support, supply continuity and total treatment cost. Excipients alone are unlikely to determine market share unless they produce a visible advantage in stability, tolerability or administration.

What FDA regulatory status applies to Prolastin-C Liquid?

Prolastin-C Liquid is an FDA-approved biologic for augmentation therapy in adults with severe hereditary alpha1-proteinase inhibitor deficiency and emphysema.[1] FDA labeling states that clinical studies have not established that augmentation therapy affects the progression of emphysema or pulmonary disease beyond the biochemical effect of increasing circulating A1PI levels.[1]

Regulatory development of a reformulated or follow-on product would likely require:

• Chemistry, manufacturing and controls comparability
• Characterization of protein structure and glycosylation
• Potency and functional activity testing
• Stability data
• Container closure studies
• Particulate and aggregation control
• Immunogenicity assessment
• Viral safety documentation
• Clinical or pharmacologic data as required by FDA

A new concentration, new container or new delivery device could require a supplemental BLA or a separate biologic application, depending on the extent of the change.

What revenue exposure is associated with Prolastin-C Liquid?

Revenue exposure is concentrated in a chronic, high-cost replacement market. Patients generally receive weekly treatment over long periods, which creates recurring demand but also exposes the product to payer controls and supply interruptions.

Key commercial sensitivities include:

• Number of diagnosed severe A1PI-deficient patients
• Treatment initiation and persistence
• Payer authorization criteria
• Reimbursement for home infusion
• Product shortages
• Plasma procurement costs
• Manufacturing yield
• Competing product discounts
• Biosimilar or follow-on entry
• Adoption of less frequent or alternative delivery systems

A liquid presentation can protect revenue by improving patient and provider retention. It can also support contracting with specialty pharmacies and home-infusion organizations. The value is greatest when convenience translates into fewer missed doses, lower administration costs or lower total site-of-care expense.

Key Takeaways

• Prolastin-C Liquid is a ready-to-use, plasma-derived alpha1-proteinase inhibitor product manufactured by Grifols.
• Its core excipient system is simple, centered on sodium phosphate, sodium chloride and water for injection, without a preservative-based differentiation strategy.[1]
• The principal formulation opportunity is improved protein stability, temperature tolerance, shelf life and concentration.
• A higher-concentration or lower-volume presentation could reduce vial count and infusion burden.
• Orange Book analysis is not the correct primary framework because the product is a biologic approved under a BLA.
• Biosimilar competition is technically difficult because of glycosylation, structural characterization, viral safety and plasma-derived manufacturing requirements.
• Manufacturing know-how, plasma access and validated viral-clearance processes may provide stronger practical protection than basic excipient claims.
• Commercial differentiation depends on convenience, supply reliability, payer access and home-infusion compatibility.

FAQs

Can Prolastin-C Liquid be reformulated with a different buffer?

Yes. A different buffer could be used by a developer if the new formulation maintains comparable safety, purity, potency, stability and administration performance. The change would require a regulatory comparability package.

Could a biosimilar use different excipients from Prolastin-C Liquid?

Yes. Biosimilars do not generally need to use identical inactive ingredients. The applicant must show that the formulation difference does not affect the biologic’s quality, safety or effectiveness.

Would a room-temperature formulation create a major commercial advantage?

Yes. A validated room-temperature storage or excursion claim could reduce shipment waste and simplify home delivery. The benefit would depend on the duration and temperature range supported by stability data.

Is polysorbate necessary in an alpha1-proteinase inhibitor liquid formulation?

Not necessarily. Surfactants can reduce interfacial stress, but a formulation may achieve acceptable stability without them. The optimal choice depends on aggregation, oxidation, container interaction and long-term stability data.

What is the most valuable lifecycle strategy for Prolastin-C Liquid?

A concentrated, low-volume formulation with improved temperature-excursion tolerance and device compatibility would likely have greater commercial value than a minor excipient substitution.

References

1. U.S. Food and Drug Administration. (2024). Prolastin-C Liquid prescribing information. Grifols Therapeutics LLC.

2. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. Center for Drug Evaluation and Research.

3. U.S. Food and Drug Administration. (2024). Regulatory information for biosimilars. Center for Drug Evaluation and Research.

4. U.S. Food and Drug Administration. (2024). Glassia prescribing information. Kamada Ltd.

5. U.S. Food and Drug Administration. (2024). Aralast NP prescribing information. Takeda Pharmaceuticals U.S.A., Inc.

6. U.S. Food and Drug Administration. (2024). Zemaira prescribing information. CSL Behring LLC.