List of Excipients in Branded Drug ZIOPTAN

Company	Tradename	Ingredient	NDC	Excipient	Potential Generic Entry
Akorn	ZIOPTAN	tafluprost	17478-609	EDETATE DISODIUM
Akorn	ZIOPTAN	tafluprost	17478-609	GLYCERIN
Akorn	ZIOPTAN	tafluprost	17478-609	HYDROCHLORIC ACID
Akorn	ZIOPTAN	tafluprost	17478-609	POLYSORBATE 80
Akorn	ZIOPTAN	tafluprost	17478-609	SODIUM HYDROXIDE
Akorn	ZIOPTAN	tafluprost	17478-609	SODIUM PHOSPHATE, MONOBASIC, DIHYDRATE
Akorn	ZIOPTAN	tafluprost	17478-609	WATER

Zioptan Excipient Strategy and Commercial Opportunities

Last updated: August 2, 2026

Zioptan is a preservative-free tafluprost ophthalmic solution, 0.0015%, supplied in single-use containers for once-daily treatment of elevated intraocular pressure and open-angle glaucoma. Its excipient system is deliberately narrow: glycerin for tonicity, dibasic sodium phosphate for buffering, edetate disodium for metal-ion control, purified water, and pH adjusters. The commercial opportunity is not a new excipient combination alone. It is the development of equivalent or improved preservative-free delivery systems that preserve tafluprost stability, dosing accuracy, container compatibility, and patient adherence while reducing packaging and manufacturing costs.

What is Zioptan and how is it formulated?

Zioptan contains tafluprost, a prostaglandin F2-alpha analog, at 0.0015%, equivalent to 15 micrograms per milliliter. The labeled dose is one drop in the affected eye or eyes once daily in the evening.[1]

Product attribute	Zioptan profile
Active ingredient	Tafluprost
Strength	0.0015%, 15 mcg/mL
Dosage form	Sterile ophthalmic solution
Preservative status	Preservative-free
Primary container	Single-use, low-density polyethylene containers
Dose frequency	Once daily
Indication	Reduction of elevated intraocular pressure
FDA application	NDA 022514
Storage	Refrigerated before opening; product-specific labeling controls apply
Packaging	Individual single-use containers in multi-unit cartons

The inactive ingredients identified in the prescribing information are glycerin, dibasic sodium phosphate, edetate disodium, hydrochloric acid and/or sodium hydroxide for pH adjustment, and water for injection.[1]

What does each Zioptan excipient do?

Excipient	Functional role	Commercial relevance
Glycerin	Tonicity adjustment and solvent contribution	Supports ocular tolerability and minimizes formulation complexity
Dibasic sodium phosphate	Buffer component	Helps control pH during storage and administration
Edetate disodium	Chelating agent	Reduces the effect of trace metals on oxidation and stability
Hydrochloric acid/sodium hydroxide	pH adjustment	Enables final pH control without adding a new functional excipient
Water for injection	Aqueous vehicle	Supports sterile ophthalmic manufacturing

Zioptan’s formulation is commercially important because it avoids benzalkonium chloride and other traditional ophthalmic preservatives. Preservative-free delivery is relevant for patients with ocular-surface disease, chronic therapy exposure, contact-lens use, or intolerance to preserved glaucoma products.

Why is the preservative-free excipient strategy commercially important?

Preservatives can damage the ocular surface over prolonged use, particularly when patients use several topical ophthalmic products. Zioptan addresses that concern through single-use packaging rather than antimicrobial preservation.

The tradeoff is higher packaging intensity. Each dose requires a sterile container, filling operation, sealing process, secondary packaging, and patient instruction. A commercial entrant must therefore optimize the full system rather than only copy the liquid composition.

The main value drivers are:

1. Preservative-free positioning.
2. Low excipient burden.
3. Once-daily dosing.
4. Compatibility with chronic glaucoma treatment.
5. Reduced preservative exposure compared with benzalkonium chloride-containing alternatives.

The central formulation challenge is maintaining sterility after opening without relying on a preservative. The container must deliver a sufficiently accurate drop, minimize microbial ingress during use, and remain compatible with tafluprost over the labeled shelf life.

What formulation patents and manufacturing IP are relevant to Zioptan?

Zioptan-related intellectual property can cover several layers:

Active ingredient and analog chemistry

Tafluprost is a small-molecule prostaglandin analog. Early patent families may cover the compound, stereochemistry, intermediates, synthesis, and therapeutic use. These rights are generally more relevant to historical launch protection than to current formulation competition.

Aqueous tafluprost compositions

Composition claims may address:

• Tafluprost concentration;
• pH range;
• buffer identity and concentration;
• tonicity agents;
• chelating agents;
• antioxidant or stabilizer systems;
• degradation limits;
• sterile ophthalmic solutions; and
• preservative-free presentations.

The commercial value of these claims depends on whether they require the precise Zioptan excipient system or cover broader combinations. A formulation claim limited to glycerin, phosphate, edetate, and a defined pH range may create a narrower design-around path than a claim covering any stable preservative-free tafluprost solution.

Container and delivery-system IP

The single-use presentation creates separate IP opportunities involving:

• Low-density polyethylene ampoules;
• Unit-dose strip configurations;
• Drop-forming geometry;
• Headspace and fill volume;
• Moisture and oxygen barrier properties;
• Sterilization methods;
• Ampoule opening systems;
• Tamper evidence; and
• Packaging that limits contamination after opening.

A generic manufacturer can match the liquid formulation yet face manufacturing or device constraints if the original container design has enforceable claims.

Manufacturing process IP

Process claims may cover sterile filtration, aseptic filling, container sealing, in-process controls, and degradation management. Manufacturing know-how can remain commercially relevant even when composition patents expire, particularly where tafluprost is sensitive to oxidation, light, hydrolysis, or trace-metal exposure.

When does Zioptan lose exclusivity?

Zioptan’s commercial exclusivity has multiple components: FDA drug exclusivity, listed patents, formulation protection, regulatory data, trademarks, and manufacturing know-how.

The FDA approved Zioptan under NDA 022514. The Orange Book is the controlling public source for listed patents and FDA exclusivity associated with that application.[2] Exact entry dates, patent expiration dates, pediatric exclusivity, and any later delisting activity should be read from the current Orange Book record rather than inferred from the original approval date.

Exclusivity layer	Relevance to Zioptan
New chemical entity exclusivity	Relevant only if tafluprost qualified as a new active ingredient for the NDA
Formulation patents	May protect preservative-free composition or stability characteristics
Method-of-use patents	May cover treatment of elevated intraocular pressure or glaucoma
Container patents	May protect unit-dose packaging and delivery configuration
Regulatory exclusivity	Controls timing of abbreviated applications under FDA rules
Trademark protection	Protects the Zioptan brand but does not prevent approved generic tafluprost
Trade secrets	May protect process parameters and impurity controls

A precise generic-entry forecast requires a current Orange Book patent table, FDA litigation certifications, and any court or settlement records. The NDA number and product label identify the regulatory baseline; they do not by themselves establish the final date for generic launch.

What Paragraph IV challenges and litigation affect Zioptan?

A generic applicant seeking approval before listed patent expiry may submit a Paragraph IV certification alleging that a listed patent is invalid, unenforceable, or not infringed. A timely patent-owner lawsuit can trigger a 30-month stay of approval under the Hatch-Waxman framework, subject to statutory exceptions and court developments.[3]

For Zioptan, the most relevant litigation questions are:

• Which patents are listed against NDA 022514?
• Are the patents directed to tafluprost, the formulation, the method of use, or the container?
• Has an ANDA applicant made a Paragraph IV certification?
• Was litigation filed within the statutory period?
• Has a court entered a judgment or preliminary injunction?
• Does a settlement permit an agreed generic launch date?
• Has FDA approval been delayed by a 30-month stay or by deficiencies unrelated to patents?

The public FDA Orange Book and federal court records are the primary sources for these determinations. No biosimilar pathway applies because tafluprost is a chemically synthesized small molecule, not a biological product. The relevant competitive pathway is an ANDA for generic tafluprost ophthalmic solution.

What generic entry risks exist for Zioptan?

Generic risk is structurally meaningful because tafluprost is administered in a conventional aqueous ophthalmic solution and has a defined active ingredient, strength, route, and dosing schedule.

A generic applicant may pursue:

• A composition identical or closely equivalent to the listed product;
• A different buffer system;
• A different tonicity agent;
• A different chelator;
• A multidose preservative-free device;
• A preserved multidose presentation;
• A unit-dose container with a different polymer; or
• A formulation supported by comparative performance and stability data.

The highest-risk scenario for the brand is an approved generic that matches the preservative-free claim and offers lower acquisition cost to payers and pharmacies. A lower-cost preserved product could compete on price but would not be fully interchangeable from a patient-tolerability or prescriber-positioning perspective.

What excipient strategies could improve on Zioptan?

Alternative tonicity systems

Glycerin can be replaced or supplemented with other ophthalmically acceptable tonicity agents, subject to tolerability and stability requirements. Candidate systems include sodium chloride, sorbitol, or combinations of polyols and salts. The target is an osmolality profile that avoids stinging and does not materially affect tafluprost stability.

Alternative buffers

Phosphate is familiar and inexpensive but can interact with divalent cations and may contribute to precipitation risks in some ophthalmic systems. Citrate, borate, or histidine-based systems may provide design-around options, although each changes regulatory, compatibility, and tolerability considerations.

Chelator optimization

Edetate disodium provides trace-metal control. A manufacturer could investigate alternative chelators or lower chelator concentrations, but any change must preserve impurity control without increasing ocular irritation or regulatory complexity.

Antioxidant and oxygen-control approaches

A formulation could use an antioxidant, oxygen-reduced headspace, light-protective packaging, or improved container barrier properties. These approaches may protect tafluprost without adding a conventional preservative. They also create patentable combinations involving composition and packaging.

Preservative-free multidose delivery

The largest commercial opportunity is a multidose preservative-free system. Such a product would reduce unit-dose plastic, simplify patient handling, and potentially lower logistics costs. The device must prevent microbial contamination through a valve, filter, one-way pathway, or controlled dispensing mechanism.

A successful system would need to demonstrate:

• Sterility through in-use testing;
• Dose uniformity across the labeled use period;
• Low extractables and leachables;
• Container-closure integrity;
• Compatibility with tafluprost;
• Drop-size consistency;
• Usability by elderly patients; and
• Stability under commercial shipping conditions.

How does Zioptan compare with competing prostaglandin products?

Product category	Active ingredient	Preservative-free option	Primary differentiation
Zioptan	Tafluprost	Yes	Preservative-free unit-dose format
Latanoprost products	Latanoprost	Some products	Broad generic availability and low price
Travatan Z	Travoprost	Yes, with alternative preservative system	SofZia-based preservative approach
Lumigan	Bimatoprost	Product-specific	Strong branded prostaglandin positioning
Vyzulta	Latanoprostene bunod	Product-specific	Nitric-oxide donating mechanism
Xalatan generics	Latanoprost	Product-specific	Mature generic competition

Zioptan’s strongest differentiation is the combination of tafluprost and preservative-free delivery. Its principal weakness is the cost and inconvenience of single-use packaging compared with low-cost multidose generic bottles.

What licensing opportunities exist for Zioptan-related technology?

Commercial opportunities fall into four categories.

Generic formulation licensing

A company with a stable preservative-free tafluprost formulation could license the formulation, regulatory package, or manufacturing process to an ANDA sponsor. The most valuable package would include comparative analytical data, impurity profiles, container compatibility, and process validation.

Device licensing

A preservative-free multidose ophthalmic dispenser could be licensed to an established glaucoma manufacturer. Device licensing may create value even when the liquid composition is not proprietary.

Regional rights

Tafluprost has different commercial positions across the United States, Europe, Japan, and other markets. Regional licensing can be structured around regulatory status, local manufacturing, reimbursement, and patent scope. European products may follow national or centralized regulatory pathways distinct from the U.S. NDA framework.

Contract manufacturing

Unit-dose ophthalmic filling requires specialized aseptic equipment and container-closure controls. Contract manufacturers with validated ampoule filling and sealing capacity can capture value without owning the drug brand.

How strong is the patent estate for Zioptan?

The strongest potential protection is likely to come from narrowly defined formulation, stability, and delivery claims rather than from broad compound claims at this stage of the product life cycle. Patent strength depends on:

• Whether core compound claims remain in force;
• The number and scope of Orange Book-listed patents;
• Claim coverage of preservative-free tafluprost;
• The availability of noninfringing buffer and tonicity alternatives;
• The enforceability of container claims;
• Published prior art involving prostaglandin ophthalmic solutions; and
• The quality of comparative stability and impurity data.

A broad claim covering any stable preservative-free tafluprost solution would present a substantial barrier. A narrow claim limited to a specific excipient ratio, pH range, or container polymer would leave more room for design-around formulations.

What is the FDA regulatory status of Zioptan?

Zioptan is an FDA-approved tafluprost ophthalmic solution under NDA 022514.[1] A generic applicant would generally pursue an ANDA demonstrating pharmaceutical equivalence and bioequivalence or other FDA-accepted equivalence standards applicable to ophthalmic products. The application would also address sterility, particulate matter, impurities, container-closure integrity, drop size, and labeling.

A new preservative-free multidose device could require a separate regulatory strategy if the device changes performance, dosing, microbial protection, or labeling. A 505(b)(2) pathway may be relevant for a materially different tafluprost formulation or delivery system, while an ANDA is the more direct route for a conventional generic equivalent.[4]

Key Takeaways

• Zioptan contains tafluprost 0.0015% in a preservative-free aqueous solution.
• Its excipient system uses glycerin, dibasic sodium phosphate, edetate disodium, water, and pH adjusters.
• The core commercial advantage is preservative-free delivery, not excipient novelty alone.
• The principal commercial weakness is the cost and inconvenience of single-use packaging.
• The most attractive development opportunity is a preservative-free multidose delivery system.
• Generic competition is more likely through an ANDA than a biosimilar pathway.
• Formulation, container, stability, and manufacturing-process patents are the most commercially relevant layers for later-stage competition.
• Current Orange Book and court records control the assessment of listed patents, Paragraph IV challenges, litigation, and settlement-based launch timing.

FAQs

Can Zioptan be reformulated with benzalkonium chloride?

Yes, a tafluprost product could theoretically use a preservative, but it would lose the principal preservative-free differentiation of Zioptan and require evaluation of ocular tolerability, stability, labeling, and regulatory equivalence.

Is edetate disodium essential to Zioptan stability?

The label identifies edetate disodium as an inactive ingredient, but the commercial necessity of that specific chelator depends on trace-metal control, impurity formation, container interaction, and validated stability data.

Could a generic Zioptan use a different buffer?

Potentially. A different buffer may create a design-around formulation, but the applicant must demonstrate equivalent quality, stability, ocular tolerability, and regulatory performance.

Does single-use packaging make Zioptan harder to manufacture?

Yes. It requires validated aseptic filling, unit-dose sealing, container-closure integrity testing, and packaging controls that are more demanding than those used for conventional multidose ophthalmic bottles.

What is the highest-value IP opportunity around tafluprost?

A preservative-free multidose delivery system with validated microbial protection, consistent drop delivery, low extractables, and long in-use stability has the strongest potential to create differentiated commercial value.

References

1. U.S. Food and Drug Administration. (2012). Zioptan (tafluprost ophthalmic solution) prescribing information. NDA 022514.

2. U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations: Orange Book. https://www.accessdata.fda.gov/scripts/cder/ob/

3. U.S. Congress. (1984). Drug Price Competition and Patent Term Restoration Act of 1984, 21 U.S.C. § 355(j).

4. U.S. Food and Drug Administration. (2024). Applications covered by section 505(b)(2). https://www.fda.gov/drugs/development-approval-process-drugs/frequently-asked-questions-505b2-applications