List of Excipients in Branded Drug ZADITOR

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Generic Drugs Containing ZADITOR

Company	Ingredient	NDC	Excipient
Alcon Laboratories Inc	ketotifen fumarate	0065-4011	BENZALKONIUM CHLORIDE
Alcon Laboratories Inc	ketotifen fumarate	0065-4011	GLYCERIN
Alcon Laboratories Inc	ketotifen fumarate	0065-4011	HYDROCHLORIC ACID
Alcon Laboratories Inc	ketotifen fumarate	0065-4011	SODIUM HYDROXIDE
Alcon Laboratories Inc	ketotifen fumarate	0065-4011	WATER

What are the Most Frequently-Used Excipients in ZADITOR?

# Of NDCs	Excipient
2	BENZALKONIUM CHLORIDE
2	GLYCERIN
2	HYDROCHLORIC ACID
2	SODIUM HYDROXIDE
2	WATER

Zaditor Excipient Strategy and Commercial Opportunities

Last updated: October 6, 2026

Zaditor is an over-the-counter ophthalmic antihistamine containing ketotifen fumarate, equivalent to ketotifen 0.025%. Its core commercial opportunity is not compound exclusivity. It is formulation differentiation: preservative-free delivery, multidose convenience, ocular-surface tolerability, device design, private-label supply, and global regulatory execution.

The primary marketed Zaditor formulation uses benzalkonium chloride, glycerin, purified water, and pH-adjusting agents. Preservative-free versions remove benzalkonium chloride and use unit-dose packaging. The active ingredient is mature, and generic entry is technically accessible. Brand value therefore depends on consumer recognition, retail distribution, packaging, formulation claims, and manufacturing reliability.

What is the active ingredient and formulation strategy for Zaditor?

Zaditor contains ketotifen fumarate ophthalmic solution. The labeled strength is generally expressed as ketotifen fumarate 0.035%, equivalent to ketotifen 0.025% [1].

Attribute	Zaditor conventional formulation	Zaditor preservative-free formulation
Active ingredient	Ketotifen fumarate	Ketotifen fumarate
Equivalent ketotifen strength	0.025%	0.025%
Dosage form	Ophthalmic solution	Ophthalmic solution
Preservative	Benzalkonium chloride, generally 0.01%	None
Primary humectant	Glycerin	Glycerin
Vehicle	Purified water	Purified water
pH adjustment	Hydrochloric acid and sodium hydroxide	Hydrochloric acid and sodium hydroxide
Packaging	Multidose bottle	Single-use vials or preservative-free container
Commercial positioning	Convenience and familiar brand	Ocular-surface tolerability and preservative avoidance

The conventional product uses benzalkonium chloride, or BAK, to control microbial contamination in a multidose bottle. BAK simplifies packaging and supports repeated use, but long-term or frequent exposure can contribute to ocular-surface irritation in susceptible users. The preservative-free configuration shifts microbial control from the formulation to the package and manufacturing process.

Which excipients does Zaditor use?

The key Zaditor excipients are benzalkonium chloride, glycerin, purified water, hydrochloric acid, and sodium hydroxide [1, 2].

Benzalkonium chloride

BAK is the central strategic excipient in the conventional product. It provides antimicrobial preservation for a multidose ophthalmic container. Its advantages include:

• Established regulatory history in ophthalmic products
• Low use concentration
• Compatibility with conventional plastic bottles
• Low cost
• Simple manufacturing and filling operations

Its principal limitation is ocular-surface tolerability. BAK exposure can be commercially disadvantageous for patients with dry eye, contact-lens use, chronic ophthalmic treatment, or sensitivity to preservatives. This creates a direct rationale for preservative-free Zaditor and competing preservative-free antihistamine products.

Glycerin

Glycerin functions primarily as a humectant and tonicity-supporting excipient. It can improve drop comfort by reducing the perception of dryness or stinging. Glycerin also supports a familiar ophthalmic formulation platform without introducing a complex solubilization system.

For ketotifen, glycerin is commercially useful because the product does not require a high-complexity delivery vehicle. A relatively simple aqueous solution supports low manufacturing cost and broad private-label applicability.

Hydrochloric acid and sodium hydroxide

These agents adjust and maintain pH. Ophthalmic pH affects:

• Chemical stability
• Solubility
• Ocular comfort
• Preservative performance
• Container compatibility

The pH system is not a major consumer-facing differentiator, but it is important to process control and stability specifications. A formulation change that improves comfort but reduces ketotifen stability, increases precipitation risk, or weakens preservative effectiveness would face a significant regulatory burden.

Purified water

Purified water is the primary vehicle. Its quality, bioburden control, and compatibility with the filling process are central to ophthalmic manufacturing. Because the formula is aqueous and low viscosity, container-closure integrity and microbial control are more commercially important than specialized rheology.

What commercial opportunities exist for Zaditor excipient innovation?

The highest-value opportunities are preservative-free packaging, differentiated multidose systems, comfort-oriented excipients, and contract-manufactured store brands.

Preservative-free unit-dose products

Preservative-free Zaditor provides the clearest formulation opportunity. Unit-dose vials remove BAK and allow the product to target:

• Patients with ocular-surface sensitivity
• Frequent users
• Contact-lens wearers, subject to label instructions
• Consumers avoiding preservatives
• Ophthalmology and optometry recommendations
• Retailers seeking premium private-label products

The tradeoff is higher packaging cost, more material consumption, greater filling complexity, and lower convenience after opening. A unit-dose design can command a premium if the product communicates a clear tolerability advantage.

Preservative-free multidose delivery

A preservative-free multidose bottle would be more commercially attractive than unit-dose packaging if it can maintain sterility through a validated one-way valve, airless system, filter-based closure, or equivalent microbial-barrier design.

The commercial requirements are demanding:

Requirement	Commercial implication
Microbial ingress protection	Determines sterility and shelf-life claims
Accurate drop delivery	Reduces waste and improves consumer satisfaction
Low residual volume	Controls cost per administered dose
Compatibility with ketotifen solution	Avoids adsorption, extractables, and leachables
Ease of priming	Reduces consumer complaints
Stable performance after repeated use	Supports multidose labeling
Child-resistant or tamper-evident packaging	May affect retail compliance and cost

This area may offer stronger practical differentiation than a new excipient because the principal technical problem is preserving sterility without BAK.

Comfort-oriented formulation

A formulation using a different tonicity agent, buffering system, or low-irritation preservative could target consumers who do not require fully preservative-free delivery. Potential development directions include:

• Alternative tonicity agents
• Lower-irritation preservation systems
• Reduced buffering capacity
• Optimized pH
• Controlled viscosity
• Drop-size reduction
• Low-surface-tension delivery

Each change would require compatibility, stability, preservative-effectiveness, extractables-and-leachables, and clinical tolerability work. The commercial value would depend on whether the resulting product can support a meaningful label claim rather than merely a technical formulation distinction.

What formulation patents could protect a Zaditor competitor?

A competitor is unlikely to obtain broad, durable protection over ketotifen ophthalmic solution itself. The active ingredient and basic dosage form are mature. Potentially protectable subject matter is narrower.

Potential patent categories

Patent category	Potential scope	Commercial strength
Preservative-free multidose container	Package, valve, microbial-barrier system	Moderate to strong if technically specific
Unit-dose packaging	Vial geometry, dose volume, material selection	Moderate
Ketotifen stability formulation	Narrow excipient ratios, pH, buffer, or stabilizer system	Moderate if unexpected stability is demonstrated
Low-irritation formulation	Specific preservative or excipient combination	Moderate, but vulnerable to obviousness attacks
Drop-size control	Nozzle, closure, or delivery geometry	Moderate
Manufacturing process	Sterile filtration, filling, sealing, or in-process controls	Usually narrow
Method of use	Allergy-specific dosing or patient subgroup	Limited if treatment method is conventional
Combination product	Ketotifen with another active ingredient	Potentially stronger, but requires clinical and regulatory support

The strongest practical protection would likely combine formulation claims with container-closure claims. A patent limited to glycerin, water, and pH adjustment would face substantial validity and design-around risks unless it demonstrated an unexpected technical effect.

When does Zaditor lose exclusivity?

Zaditor’s compound exclusivity is no longer the principal market barrier. Ketotifen has been used internationally for decades, and the U.S. product is sold through the OTC pathway. The brand’s commercial protection is based primarily on trademark, consumer recognition, distribution, quality systems, and product presentation.

Exclusivity or barrier	Status
Ketotifen active ingredient	Mature
Basic ketotifen ophthalmic solution	Technically accessible to competitors
U.S. prescription-to-OTC transition	Completed
Brand trademark	Continues subject to use and registration
BAK-containing formula	Not a strong standalone exclusivity barrier
Preservative-free package	Potentially protectable through device or formulation patents
Retail shelf position	Commercial rather than legal protection
Manufacturing know-how	Potentially valuable but generally confidential

A current, product-specific patent conclusion requires review of the FDA Orange Book, issued patents, terminal disclaimers, continuations, and litigation records. The public regulatory profile supports the commercial conclusion that Zaditor’s principal protection is brand and execution rather than a broad active-ingredient patent estate [3].

What is the Orange Book status of Zaditor?

Zaditor is associated with an FDA-approved ophthalmic product that transitioned into the OTC market. FDA labeling and Drugs@FDA records are the primary sources for product identity, strength, dosage form, sponsor history, and approval information [1, 4].

The relevant competitive question is not simply whether an Orange Book patent is listed. It is whether a prospective competitor must:

1. Rely on an abbreviated or alternative FDA pathway.
2. Match the reference formulation closely enough to support approval.
3. Address preservative and container differences.
4. Demonstrate appropriate quality and stability.
5. Avoid active patents covering a specific package or formulation.
6. Obtain retail distribution against established brands.

For a ketotifen OTC product, an applicant may pursue an approved drug application or the applicable OTC regulatory route, depending on the formulation, labeling, and current FDA requirements. A materially different preservative-free product may require more than a simple formulation substitution.

Are Paragraph IV challenges relevant to Zaditor?

Paragraph IV litigation is less central for Zaditor than for a prescription product with active Orange Book patents. A generic or private-label sponsor could still challenge listed patents if FDA records identify enforceable patents covering the reference product or its formulation. The practical probability of a high-value Paragraph IV dispute is limited unless a newer preservative-free formulation or delivery device has active patent protection.

Potential disputes could involve:

• Whether a preservative-free formulation infringes a formulation patent
• Whether a multidose sterile package infringes a device patent
• Whether a competitor’s excipient ratio falls within a claim
• Whether an asserted patent is obvious over earlier ketotifen formulations
• Whether a method-of-use claim is relevant to OTC labeling

The likely market outcome is more price competition and retailer substitution than prolonged patent litigation.

Which companies compete with Zaditor?

Zaditor competes across three groups: branded ketotifen products, generic ketotifen products, and alternative antihistamine or mast-cell stabilizer eye drops.

Product or category	Active ingredient	Competitive position
Zaditor	Ketotifen	Established branded OTC product
Alaway	Ketotifen	Direct branded OTC competitor
Generic ketotifen	Ketotifen	Price-led competition
Pataday	Olopatadine	Strong branded antihistamine competitor
Lastacaft	Alcaftadine	Branded allergy-eye-drop alternative
Store-brand allergy drops	Ketotifen, olopatadine, or other actives	Retailer-controlled price competition

The direct product comparison is ketotifen versus ketotifen. In that segment, excipient and packaging differences can influence consumer choice. Across active ingredients, olopatadine and alcaftadine compete through dosing, brand recognition, perceived efficacy, and retail placement.

How does Zaditor compare with Alaway and generic ketotifen?

Zaditor and Alaway are pharmacologically close because both use ketotifen. The more important differences are brand ownership, packaging, retail distribution, consumer advertising, preservative status, and price.

Factor	Zaditor	Alaway	Generic ketotifen
Active ingredient	Ketotifen	Ketotifen	Ketotifen
Core formulation opportunity	Preservative-free and comfort positioning	Similar	Cost and supply
Brand premium	Established	Established	Usually limited
Retail leverage	High if supported by shelf placement	High if supported by shelf placement	Depends on retailer
Excipient differentiation	Moderate	Moderate	Often limited
Patent leverage	Likely narrow	Likely narrow	Must avoid active claims
Main commercial risk	Brand substitution and price erosion	Brand substitution and price erosion	Margin compression

A generic supplier can compete effectively without creating a superior formulation if it offers reliable supply, attractive wholesale pricing, and acceptable packaging. A premium challenger needs a visible consumer benefit, particularly preservative-free use or lower waste.

What FDA regulatory issues affect new Zaditor formulations?

A new ketotifen ophthalmic product must address more than active-ingredient identity. Key regulatory issues include:

• Sterility assurance
• Container-closure integrity
• Preservative effectiveness where applicable
• Stability through labeled shelf life
• Dose uniformity
• Drop size and delivered volume
• pH and osmolality
• Particulate matter
• Extractables and leachables
• In-use stability
• Compatibility with contact lenses, if claimed
• Labeling and OTC consumer comprehension

A change from BAK-containing multidose packaging to preservative-free multidose packaging can increase development complexity even if the active ingredient and concentration remain unchanged. The package becomes part of the microbial-control strategy.

FDA’s OTC ophthalmic framework and product-specific approval records should be read together. The applicable route depends on the active ingredient, concentration, labeling, dosage form, and formulation differences [4, 5].

What manufacturing and intellectual-property barriers exist?

Manufacturing barriers are moderate. Ketotifen aqueous ophthalmic solution is not inherently difficult to produce, but sterile operations and packaging quality are critical.

The highest-value manufacturing capabilities include:

1. Sterile compounding and filtration.
2. Aseptic filling.
3. Low-particulate processing.
4. High-integrity bottle or vial sealing.
5. Preservative-effectiveness testing.
6. Automated visual inspection.
7. Device assembly for preservative-free multidose systems.
8. Stability testing in commercial packaging.

The most defensible know-how may reside in process parameters, package performance, component sourcing, and defect-control systems rather than in the basic formula.

What licensing and partnership opportunities exist?

No major public licensing transaction is required to commercialize a standard ketotifen ophthalmic product. Commercial partnerships are more likely to involve:

• OTC brand licensing
• Private-label supply agreements
• Contract manufacturing
• Preservative-free container technology
• Retailer-exclusive packaging
• Regional distribution rights
• Co-development of allergy-eye-care portfolios

A formulation-device company could license a preservative-free multidose platform to an OTC brand owner. A generic manufacturer could license regional rights to a ketotifen product while retaining sterile filling capability. Retailers could use private-label ketotifen to pressure branded pricing while preserving category participation.

Public revenue attributable specifically to Zaditor is generally not disclosed. The relevant exposure is category-level allergy-eye-drop sales, not a separately reported Zaditor revenue line.

What generic launch scenarios exist for Zaditor?

Low-cost generic launch

A supplier launches a conventional ketotifen ophthalmic solution using a standard preservative system and competes primarily on price. This is the lowest-complexity scenario and carries the greatest margin pressure.

Store-brand substitution

A retailer replaces or supplements branded Zaditor with a private-label ketotifen product. Packaging, supply reliability, and retail margin become more important than formulation novelty.

Preservative-free premium launch

A sponsor launches single-use or preservative-free multidose ketotifen. This supports premium pricing but requires stronger packaging validation and a clear consumer message.

Device-led differentiation

A sponsor combines ketotifen with a low-waste, low-drop-volume, or ergonomic delivery system. The package may support patent protection and retail differentiation if the performance benefit is measurable.

Global regional launch

A manufacturer uses the same ketotifen platform across jurisdictions, adapting labels, preservative requirements, pack sizes, and regulatory pathways. Geographic coverage depends on local registration and trademark rights rather than U.S. exclusivity alone.

Key Takeaways

• Zaditor contains ketotifen fumarate equivalent to ketotifen 0.025%.
• The conventional product uses benzalkonium chloride, glycerin, purified water, and pH-adjusting agents.
• Preservative-free packaging is the strongest commercial excipient opportunity.
• A preservative-free multidose system has greater upside than a simple excipient substitution but carries higher validation and manufacturing costs.
• Ketotifen’s mature status limits the value of broad compound or basic formulation patents.
• Potentially valuable IP is more likely to cover container systems, drop delivery, narrow stability formulations, or manufacturing processes.
• Generic and private-label competition can enter through price and supply reliability without major formulation innovation.
• The main commercial risks are retailer substitution, price erosion, competing antihistamine products, and loss of brand shelf position.
• Zaditor-specific revenue is not generally disclosed separately, so category exposure is the more practical commercial metric.

FAQs

Is benzalkonium chloride in Zaditor?

The conventional multidose Zaditor ophthalmic solution uses benzalkonium chloride as a preservative. Preservative-free versions eliminate BAK through unit-dose or specialized multidose packaging.

Can a company make a generic version of Zaditor?

Yes. A company can pursue a ketotifen ophthalmic product through the applicable FDA regulatory pathway, subject to formulation, labeling, quality, sterility, and patent requirements.

Does a preservative-free Zaditor formulation have stronger commercial value?

Usually. Preservative-free positioning can support premium pricing and target consumers concerned about ocular-surface irritation, although packaging and manufacturing costs are higher.

What is the most valuable patent opportunity in ketotifen eye drops?

The strongest opportunity is likely a technically specific preservative-free multidose container, delivery system, or stability-enhancing formulation rather than a broad claim to ketotifen ophthalmic solution.

Who are Zaditor’s closest competitors?

Alaway is the closest branded ketotifen competitor. Generic ketotifen products compete on price. Pataday and Lastacaft compete as branded antihistamine eye-drop alternatives with different active ingredients.

References

1. DailyMed. (n.d.). Zaditor: Ketotifen fumarate ophthalmic solution, 0.025% equivalent ketotifen. U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/

2. Alcon Laboratories, Inc. (n.d.). Zaditor ophthalmic solution product labeling. U.S. Food and Drug Administration labeling repository.

3. 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/

4. U.S. Food and Drug Administration. (n.d.). Drugs@FDA: FDA-approved drugs. https://www.accessdata.fda.gov/scripts/cder/daf/

5. U.S. Food and Drug Administration. (n.d.). 21 CFR Part 349: Ophthalmic drug products for over-the-counter human use. Electronic Code of Federal Regulations. https://www.ecfr.gov/current/title-21/chapter-I/subchapter-D/part-349