List of Excipients in Branded Drug VITRASE

Last updated: September 1, 2026

Vitrase is an ovine hyaluronidase injection whose commercial opportunity depends on reformulation, reliable animal-derived supply, and differentiation from recombinant Hylenex and bovine Amphadase. The original product is a legacy injectable rather than a strong current platform brand. Its most practical opportunities are preservative-free presentations, ready-to-use specialty-care packaging, improved stability, and combination use with high-value injectable therapies. The main constraints are limited product-specific exclusivity, substitution by competing hyaluronidase products, and regulatory scrutiny of animal-derived excipients and raw materials.

Vitrase Excipient Strategy and Commercial Opportunities

What is Vitrase and how does its formulation work?

Vitrase is hyaluronidase injection, ovine, supplied at 200 USP units/mL. Hyaluronidase temporarily depolymerizes hyaluronic acid in the extracellular matrix, increasing tissue permeability and accelerating dispersion and absorption of subcutaneously administered fluids and drugs. The FDA-approved uses include subcutaneous fluid administration, dispersion and absorption of injected drugs, and subcutaneous urography.[1]

The product is associated with ISTA Pharmaceuticals and was later part of Bausch + Lomb's ophthalmic and pharmaceutical portfolio. The U.S. reference product was discontinued for commercial reasons, according to FDA records, rather than withdrawn for safety or efficacy concerns.[2]

Vitrase formulation profile

Attribute	Vitrase profile
Active ingredient	Ovine hyaluronidase
Strength	200 USP units/mL
Dosage form	Sterile injectable solution
Route	Subcutaneous; other clinical administration uses may be physician-directed
Primary function	Enhances dispersion and absorption of injected fluids and drugs
Key excipient functions	Isotonicity, pH adjustment, protein stabilization
Animal-derived component	Ovine enzyme
Preservative strategy	Preservative-free single-use positioning is commercially attractive
Primary competitors	Hylenex recombinant human hyaluronidase; Amphadase bovine hyaluronidase
FDA product identifier	NDA 021664

The historical Vitrase label identifies lactose and sodium chloride among the inactive ingredients, with calcium chloride and pH adjustment components used in the injectable formulation.[1] Exact excipient quantities and current commercial presentation should be verified against the applicable regulatory record before a development or licensing decision.

What excipients are most important for a Vitrase reformulation?

The excipient strategy must protect enzyme activity without creating new immunogenicity, compatibility, or administration risks. Hyaluronidase is a protein, so the formulation must control adsorption, aggregation, oxidation, deamidation, agitation sensitivity, and temperature exposure.

Lactose as a stabilizer

Lactose can act as a protein stabilizer by reducing conformational stress during storage and drying-related processing. In a liquid injectable product, its value depends on concentration, pH, ionic strength, and the enzyme's long-term aggregation profile.

A lactose-based strategy has four commercial advantages:

1. It maintains continuity with the historical Vitrase formulation.
2. It avoids introducing a new synthetic surfactant into a legacy product.
3. It can support a relatively simple excipient declaration.
4. It may reduce development complexity when bridging to the existing product.

The main limitation is that lactose is unsuitable for some patients with clinically relevant galactose metabolism disorders or hereditary lactase-related conditions. A new formulation should assess whether lactose can be replaced by trehalose, sucrose, or another stabilizing carbohydrate without changing the product's clinical performance.

Sodium chloride and calcium chloride

Sodium chloride supports isotonicity and injection comfort. Calcium chloride may contribute to formulation compatibility or enzyme stability, but its concentration must be controlled because calcium can affect protein conformation, aggregation, and interaction with container surfaces.

A reformulation that removes or materially changes calcium chloride would require comparative stability, activity, and compatibility work. The change could be commercially useful if it improves compatibility with co-administered drugs or reduces precipitation risk.

Surfactants

Polysorbate 20, polysorbate 80, poloxamers, and related surfactants can reduce interfacial adsorption during filling, shipping, and injection. They also introduce degradation risks, including peroxide formation and hydrolysis. A surfactant-free formulation could be differentiated for sensitive patients and specialty clinics, but only if the product maintains acceptable aggregation and subvisible-particle profiles.

For a multidose product, a surfactant may be necessary to preserve physical stability. For a single-use syringe or vial, lower surfactant exposure could be a stronger commercial position.

Buffers and pH control

Hyaluronidase activity and stability are pH-dependent. A reformulation should compare phosphate, citrate, histidine, acetate, and other low-concentration buffers. Buffer selection affects:

• Enzyme activity after storage
• Injection-site tolerability
• Compatibility with biologics and small-molecule injectables
• Freeze-thaw performance
• Interaction with glass, elastomer, and polymer containers

A histidine-based formulation could support protein stability, while phosphate may offer manufacturing familiarity. Citrate can be useful in some protein products but may create tolerability or compatibility issues at higher concentrations.

Preservatives

Benzyl alcohol, phenol, and m-cresol are potential multidose preservatives but are poor fits for a premium specialty injectable unless a multidose presentation has clear market value. Preservative-free packaging is more commercially attractive for ophthalmic, anesthetic, pediatric, and hospital use.

What Vitrase excipient patents and formulation patents are relevant?

Vitrase's commercial protection is more likely to depend on formulation, container, use, and manufacturing claims than on broad composition-of-matter protection for hyaluronidase. The enzyme itself is an established biological material, and the original product is not positioned as a newly invented chemical entity.

Patent categories with commercial relevance

Patent category	Potential value for Vitrase	Typical claim focus
Stable liquid formulation	High	pH, ionic strength, carbohydrate, surfactant, enzyme concentration
Lyophilized formulation	Medium to high	Cake structure, reconstitution time, residual moisture, stabilizer system
Prefilled syringe	Medium	Device compatibility, extractables, dose accuracy, storage
Ophthalmic delivery	Medium	Injection technique, local anesthetic use, ocular dispersion
Co-administration method	High	Hyaluronidase with biologic, oncology drug, anesthetic, or contrast agent
Animal-derived material control	Medium	Source qualification, viral safety, purification, release testing
Recombinant replacement	High	Recombinant human hyaluronidase sequence, production, formulation
Manufacturing process	Medium	Purification, viral clearance, enzyme activity, impurity limits

Public FDA product records do not establish a broad, durable Orange Book patent estate for Vitrase comparable to the estates surrounding major patented biologics or drug-delivery platforms. The key commercial distinction is between patents specifically covering Vitrase and patents covering competing hyaluronidase technologies, particularly recombinant human hyaluronidase and Halozyme's ENHANZE platform.

A freedom-to-operate review should separate:

• Vitrase-specific patents assigned to ISTA or successor companies.
• Third-party patents covering hyaluronidase formulations.
• Platform patents covering co-formulation or co-administration with therapeutic proteins.
• Device patents covering prefilled syringes and autoinjectors.
• Process patents covering purification of ovine or bovine enzyme.

When did Vitrase lose exclusivity and what is its Orange Book status?

Vitrase's market exclusivity is effectively a legacy issue. NDA 021664 was approved in 2004, and the product is identified in FDA records as discontinued.[2] There is no current commercial exclusivity profile comparable to a marketed new molecular entity.

FDA and Orange Book implications

The principal regulatory questions are:

• Whether NDA 021664 remains listed as approved or discontinued.
• Whether the reference product has an active commercial listing.
• Whether any patents or regulatory exclusivity periods remain listed.
• Whether an abbreviated new drug application can use Vitrase as the reference product.
• Whether a proposed product would instead require a 505(b)(2) application because of differences in source enzyme, formulation, route, or presentation.

The Orange Book does not create patent protection where no enforceable listed patent exists. A successor product would need to assess whether a generic pathway is viable or whether a 505(b)(2) application is more appropriate.

Are Paragraph IV challenges relevant to Vitrase?

Paragraph IV litigation risk appears limited for the discontinued Vitrase product. A challenger would need an active reference-product framework and a viable abbreviated pathway. If the reference product is no longer marketed or lacks a suitable current reference listing, the commercial pathway may shift toward a 505(b)(2) application or a new NDA strategy.

Generic launch scenarios

Scenario	Likely pathway	Commercial consequence
Same ovine enzyme, same strength and dosage form	ANDA if regulatory reference requirements are satisfied	Lowest development cost
Same functional class, different animal source	505(b)(2) or NDA	More clinical and CMC bridging
Recombinant human hyaluronidase	351(a) biologic or applicable FDA pathway	Higher development cost, stronger differentiation
New prefilled syringe	ANDA or 505(b)(2), depending on changes	Device and extractables work required
New indication with established enzyme	505(b)(2) or supplemental application	Method-of-use opportunity
Combination product with a biologic	505(b)(2), biologic supplement, or new combination strategy	Higher partnering value

The most credible generic opportunity is a sterile injectable hyaluronidase product with equivalent strength and activity. The strongest branded opportunity is a differentiated formulation or delivery system rather than a simple Vitrase copy.

What formulation opportunities exist for Vitrase?

Preservative-free prefilled syringe

A single-use syringe containing 200 units/mL could reduce preparation time and dosing errors in outpatient clinics, ophthalmology, plastic surgery, anesthesia, and infusion settings. Commercial value would depend on:

• Low extractables and leachables
• Stable enzyme activity over shelf life
• Minimal silicone-oil interaction
• Reliable injection force
• Protection from light and agitation
• Unit-dose packaging that reduces waste

The product could command a premium over multidose vials if it improves workflow and reduces contamination risk.

Higher-concentration presentation

A more concentrated formulation could reduce injection volume and improve use with selected specialty therapies. This strategy has technical risks. Increasing enzyme concentration can increase aggregation, viscosity, adsorption, and injection force. It could also change local tolerability and the dose-volume relationship established in the original label.

A higher-strength product would require comparative pharmacology and clinical bridging. It is more likely to be protected through formulation and use patents than through the original Vitrase estate.

Lyophilized product

A freeze-dried Vitrase presentation could improve storage stability and simplify global distribution where cold-chain infrastructure is limited. The tradeoff is the need for diluent handling, reconstitution training, additional packaging, and more complex manufacturing.

Lyophilization is most attractive if liquid stability is inadequate or if the product is intended for markets with difficult logistics. It is less attractive for high-throughput U.S. hospital use, where ready-to-use presentations are preferred.

Combination with injectable therapies

Hyaluronidase can increase tissue dispersion or absorption of selected injected drugs. Potential commercial applications include:

• Local anesthetics
• Subcutaneous immunoglobulin
• Monoclonal antibodies
• Oncology biologics
• Enzyme-replacement products
• Contrast agents
• Hydration fluids

The commercial opportunity is strongest where hyaluronidase can reduce infusion time, enable subcutaneous administration, or expand the use of a high-cost biologic. Combination claims must be supported by product-specific compatibility, activity, pharmacokinetic, and safety data.

How does Vitrase compare with Hylenex and Amphadase?

Product	Enzyme source	Strategic advantage	Strategic limitation
Vitrase	Ovine	Established legacy formulation and known clinical use	Discontinued commercial status and animal-derived source
Hylenex	Recombinant human	Human recombinant source; strong positioning for modern biologic delivery	Higher development and manufacturing complexity; platform patent exposure
Amphadase	Bovine	Established animal-derived alternative	Potential immunogenicity and raw-material concerns
New recombinant entrant	Recombinant human or engineered variant	Opportunity for improved potency, stability, or reduced immunogenicity	Requires substantial CMC and clinical investment

Hylenex is the strongest benchmark for a premium reformulation. A new Vitrase-derived product would need a clear reason to win against recombinant human hyaluronidase. Lower price alone could support hospital tenders, but specialty markets are more likely to reward convenience, compatibility, and delivery performance.

Which companies are relevant to Vitrase licensing and competition?

The relevant commercial counterparties include:

• Bausch + Lomb or successor holders of legacy Vitrase rights.
• Halozyme Therapeutics, whose ENHANZE technology is built around recombinant human hyaluronidase PH20.
• Amphastar Pharmaceuticals, associated with Amphadase and injectable hyaluronidase commercialization.
• Generic injectable manufacturers with sterile biologic filling and vial or syringe capacity.
• Contract development and manufacturing organizations with animal-derived enzyme purification capabilities.
• Specialty pharmaceutical companies developing subcutaneous versions of high-value biologics.

Licensing value would be highest if the asset includes more than the discontinued Vitrase brand. A package containing manufacturing know-how, regulatory history, source-enzyme controls, validated assays, and rights to a new presentation would be more valuable than a standalone legacy NDA.

What manufacturing and IP barriers affect Vitrase opportunities?

The main barriers are manufacturing and regulatory rather than basic molecule patent risk.

Manufacturing barriers

Ovine hyaluronidase requires control of:

• Source-animal qualification
• Viral and adventitious-agent safety
• Bioburden and endotoxin
• Enzyme potency and identity
• Host-tissue impurities
• Batch-to-batch variability
• Aggregates and particulates
• Residual process chemicals
• Sterile filtration and aseptic filling

Animal-derived sourcing can create supply-chain and public-health concerns. Recombinant production avoids some of these issues but requires a more sophisticated cell-culture and purification platform.

Geographic coverage

U.S. opportunity is constrained by the product's legacy status and competition from Hylenex and Amphadase. European and emerging-market opportunities may exist where injectable hyaluronidase access is limited, but each jurisdiction will evaluate:

• Animal-origin documentation
• Pharmacopoeial compliance
• Local reference-product availability
• Biological equivalence
• Cold-chain requirements
• Import controls
• GMP inspection history

A global strategy should prioritize a modern, preservative-free product rather than attempt to replicate an older U.S. vial presentation without differentiation.

What revenue exposure and commercial opportunity exist?

Vitrase itself should not be treated as a major current revenue asset without evidence of an active marketed product and verified sales data. The commercial opportunity lies in a replacement or successor product.

Revenue pools

Opportunity	Revenue profile	Main buyer
Low-cost generic vial	Volume-driven, lower margin	Hospitals and wholesalers
Preservative-free syringe	Premium, moderate volume	Clinics and outpatient facilities
High-concentration product	Premium if clinically useful	Specialty practices and infusion centers
Biologic co-formulation	High value, partnership-driven	Biopharma companies
Recombinant human product	Premium, higher investment	Hospitals and specialty care
Emerging-market injectable	Volume growth, pricing pressure	Government and distributor channels

The most defensible commercial model combines a base injectable product with formulation and delivery rights that can be licensed to developers of subcutaneous biologics.

Key Takeaways

• Vitrase is a legacy ovine hyaluronidase injection, historically supplied at 200 USP units/mL.
• The original product's commercial status is discontinued in FDA records, limiting the value of a simple brand revival.
• Lactose, sodium chloride, calcium chloride, pH control, and preservative selection are central formulation variables.
• A preservative-free prefilled syringe is the clearest near-term product opportunity.
• Higher concentration, lyophilization, and biologic co-administration offer stronger differentiation but require more development work.
• Paragraph IV risk appears limited unless a viable active reference-product pathway is established.
• Hylenex is the principal benchmark because recombinant human hyaluronidase has a stronger modern product position.
• Ovine raw-material controls and manufacturing consistency are major barriers.
• The highest-value IP strategy would combine formulation, device, manufacturing, and method-of-use claims.
• Licensing value depends more on a modernized product package than on the legacy Vitrase brand alone.

FAQs About Vitrase Excipient Strategy

Is lactose essential to the Vitrase formulation?

No. Lactose is part of the historical formulation strategy, but a new product could evaluate trehalose, sucrose, amino acids, surfactants, or other stabilizers. Any replacement would require comparative stability, activity, safety, and regulatory bridging.

Can Vitrase be reformulated as a recombinant human hyaluronidase?

Yes, but the resulting product would not be a simple formulation change. A recombinant human enzyme would raise new characterization, manufacturing, immunogenicity, comparability, and regulatory questions.

Does a Vitrase prefilled syringe have patent value?

Potentially. Patent value could arise from the combination of enzyme concentration, excipient system, syringe materials, siliconization controls, storage conditions, and administration method. A generic prefilled presentation would not automatically infringe those claims.

Is Vitrase suitable for co-formulation with monoclonal antibodies?

Potentially, but compatibility is molecule-specific. Hyaluronidase can affect dispersion and absorption, while the antibody may affect enzyme activity, aggregation, viscosity, and container compatibility. Each combination requires dedicated CMC and clinical evaluation.

What is the strongest commercial strategy for a Vitrase successor?

A preservative-free, ready-to-use recombinant or highly controlled animal-derived hyaluronidase in a prefilled syringe, supported by compatibility data with selected subcutaneous biologics, offers the strongest combination of differentiation, pricing potential, and licensing value.

References

1. U.S. Food and Drug Administration. (2004). Vitrase (hyaluronidase injection, ovine) prescribing information. NDA 021664.

2. U.S. Food and Drug Administration. (n.d.). Drugs@FDA: Vitrase, NDA 021664. Retrieved from https://www.accessdata.fda.gov/scripts/cder/daf/

3. U.S. Food and Drug Administration. (2023). Approved drug products with therapeutic equivalence evaluations. Center for Drug Evaluation and Research.

4. Halozyme Therapeutics, Inc. (2024). Annual report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934. U.S. Securities and Exchange Commission.

5. U.S. Food and Drug Administration. (2020). Q5C stability testing of biotechnological/biological products: Guidance for industry. Center for Biologics Evaluation and Research.