List of Excipients in Branded Drug OXAPROZIN

Company	Tradename	Ingredient	NDC	Excipient	Potential Generic Entry
Greenstone LLC	OXAPROZIN	oxaprozin	59762-6002	CELLULOSE, MICROCRYSTALLINE
Greenstone LLC	OXAPROZIN	oxaprozin	59762-6002	HYPROMELLOSE
Greenstone LLC	OXAPROZIN	oxaprozin	59762-6002	MAGNESIUM STEARATE
Greenstone LLC	OXAPROZIN	oxaprozin	59762-6002	METHYLCELLULOSE
Greenstone LLC	OXAPROZIN	oxaprozin	59762-6002	POLACRILIN POTASSIUM

Generic Drugs Containing OXAPROZIN

Company	Ingredient	NDC	Excipient
Teva Pharmaceuticals USA Inc	oxaprozin	0093-0924	CARNAUBA WAX
Teva Pharmaceuticals USA Inc	oxaprozin	0093-0924	CELLULOSE, MICROCRYSTALLINE
Teva Pharmaceuticals USA Inc	oxaprozin	0093-0924	HYPROMELLOSE 2910
Teva Pharmaceuticals USA Inc	oxaprozin	0093-0924	MAGNESIUM STEARATE
Teva Pharmaceuticals USA Inc	oxaprozin	0093-0924	METHYLCELLULOSE

What are the Most Frequently-Used Excipients in OXAPROZIN?

# Of NDCs	Excipient
4	CARNAUBA WAX
27	CELLULOSE, MICROCRYSTALLINE
1	CROSCARMELLOSE SODIUM
8	D&C YELLOW NO. 10
8	FD&C YELLOW NO. 6

Oxaprozin Excipient Strategy and Commercial Opportunities

Last updated: August 26, 2026

Oxaprozin is a mature, orally administered NSAID with broad generic availability and limited legacy exclusivity. The commercial opportunity is not in reproducing a conventional immediate-release tablet. It is in improving dissolution, reducing gastrointestinal exposure, extending dosing convenience, or creating differentiated dosage forms that support a new product profile.

What is the current FDA status of oxaprozin?

Oxaprozin is an FDA-approved nonsteroidal anti-inflammatory drug used for osteoarthritis and rheumatoid arthritis. The original branded product, Daypro, was developed by G.D. Searle and later associated with Pfizer. Oxaprozin is now marketed primarily through generic immediate-release tablets.

Attribute	Oxaprozin status
Active ingredient	Oxaprozin
Drug class	NSAID
Main indications	Osteoarthritis and rheumatoid arthritis
Common strengths	600 mg and 1200 mg daily-dose configurations, depending on product
Dosage form	Immediate-release oral tablet
FDA pathway for generics	ANDA
Reference product	Daypro
Current market structure	Generic-dominated
Biosimilar relevance	None; oxaprozin is a small molecule
Orange Book relevance	Product-specific listing and patent status must be confirmed against the current FDA edition
Primary commercial barrier	Price competition and high dose load
Main formulation opportunity	Solubility, dose reduction, modified release, and GI-risk differentiation

The FDA label identifies standard NSAID risks, including gastrointestinal bleeding, cardiovascular events, renal toxicity, hypertension, and hypersensitivity reactions. An excipient strategy cannot eliminate those pharmacologic risks, but it can address tablet size, dissolution behavior, dose administration, and tolerability-related product positioning. [1]

What patents protect oxaprozin?

Oxaprozin’s original composition-of-matter and early formulation protection are commercially exhausted in the United States. Generic oxaprozin products have been marketed through ANDAs for years, and the product does not have the exclusivity profile of a recently approved small molecule.

The practical patent position is:

Patent category	Commercial assessment
Original active-ingredient patents	Expired or no longer commercially blocking
Original tablet patents	Expired or superseded by generic competition
New formulation patents	Potentially available for novel dosage forms
Method-of-use patents	Possible only for genuinely differentiated clinical use
Manufacturing patents	Potentially useful for cost, purity, particle engineering, or process control
Orange Book-listed patents	Must be checked against the current FDA listing for the specific reference product
Paragraph IV exposure	Relevant only if a new listed patent or reformulated reference product creates a patent dispute

A new oxaprozin product could obtain patent protection for a particular formulation, release profile, particle-size distribution, manufacturing process, or therapeutic use. A patent covering only the use of routine excipients in a conventional tablet would face substantial validity and obviousness risk.

When does oxaprozin lose exclusivity?

Oxaprozin has already lost its principal U.S. small-molecule exclusivity. Generic competition is therefore not an anticipated future event; it is the existing market condition.

A new oxaprozin product would need to establish a separate intellectual-property position. Potential patent terms could run for 20 years from the relevant nonprovisional filing date, subject to patent-term adjustment and any applicable patent-term extension. FDA regulatory exclusivity would depend on the approval pathway and the novelty of the product.

A reformulated product based on the same active ingredient would not automatically receive new chemical-entity exclusivity. A 505(b)(2) application could be relevant where the sponsor relies partly on existing oxaprozin data but introduces a clinically meaningful change in dosage form, route, dosing frequency, or formulation. [2]

What excipients are used in generic oxaprozin tablets?

Generic oxaprozin tablets commonly use standard solid-oral excipients, but the exact composition varies by manufacturer. Public labels for generic products may identify combinations of microcrystalline cellulose, povidone, crospovidone, sodium lauryl sulfate, magnesium stearate, colloidal silicon dioxide, hypromellose, polyethylene glycol, and titanium dioxide. [3]

These excipients generally perform the following functions:

Excipient class	Typical function	Strategic relevance
Microcrystalline cellulose	Diluent and compressibility aid	Supports high-dose tablet manufacture
Povidone	Binder	Improves granule and tablet strength
Crospovidone	Superdisintegrant	Accelerates tablet breakup
Sodium lauryl sulfate	Wetting agent	Can improve dissolution of poorly wettable drug
Magnesium stearate	Lubricant	Supports ejection and manufacturing efficiency
Colloidal silicon dioxide	Glidant and moisture-control aid	Improves powder flow
Hypromellose	Film former or release-control polymer	Useful for coating and modified release
Polyethylene glycol	Plasticizer in film coating	Supports coating flexibility
Titanium dioxide	Opacifier and colorant	Aesthetic and light-protection function

The existing formulation platform is inexpensive, conventional, and compatible with ANDA development. It is not, by itself, a strong commercial differentiator.

What formulation challenges affect oxaprozin?

Oxaprozin has a high dose burden because adult dosing can reach 1200 mg once daily. A large tablet or multiple-tablet regimen can impair adherence and increase manufacturing and packaging costs.

Oxaprozin is a weakly acidic compound with limited aqueous solubility under some conditions. Its dissolution profile may be affected by particle size, pH, wetting, granulation method, compression force, and lubricant exposure. Those properties make formulation and process control more commercially relevant than in a highly soluble, low-dose compound.

The principal development risks are:

1. High active load and tablet size.
2. Variable dissolution caused by hydrophobic drug particles or over-lubrication.
3. Potential mismatch between rapid dissolution and NSAID-related gastrointestinal exposure.
4. Difficulty obtaining a meaningful clinical advantage over low-cost generic tablets.
5. Need to demonstrate bioequivalence or clinical benefit under the selected FDA pathway.

What excipient strategies could improve oxaprozin?

Immediate-release dissolution enhancement

A low-cost immediate-release product could use particle-size reduction, wetting agents, optimized disintegrants, and controlled granulation. Sodium lauryl sulfate or another surfactant may improve wetting, but the level must be controlled because excessive surfactant can affect tablet properties, dissolution reproducibility, and gastrointestinal tolerability.

A practical platform would combine:

• Micronized or controlled-particle-size oxaprozin.
• Microcrystalline cellulose for high-dose compression.
• Crospovidone for rapid disintegration.
• A low, validated surfactant concentration.
• Controlled magnesium stearate blending.
• Film coating for swallowability and dose identification.

This strategy has the lowest regulatory and manufacturing risk but also the weakest differentiation. It is most suitable for a low-cost generic or a supply-constrained market rather than a premium branded product.

Amorphous solid dispersion

An amorphous solid dispersion could improve apparent solubility and dissolution through polymers such as hypromellose acetate succinate, polyvinylpyrrolidone, or copovidone. Hot-melt extrusion or spray drying could be used, depending on thermal stability and process performance.

The commercial case depends on whether the formulation produces:

• Faster and more complete dissolution.
• Reduced food effect.
• Lower dose requirements.
• More consistent exposure.
• A measurable clinical benefit.

The main risks are recrystallization, moisture sensitivity, residual solvent control, scale-up complexity, and higher cost of goods. A dispersion product would be more patentable than a conventional tablet but would require stronger analytical and stability packages.

Lipid-based or self-emulsifying systems

A lipid-based formulation could address dissolution limitations by improving drug wetting and maintaining the active ingredient in a solubilized state. This approach is technically more attractive for a softgel or liquid-filled capsule than for a conventional high-dose tablet.

The high dose makes capsule fill volume a major issue. A lipid system may therefore be more practical if it substantially improves bioavailability and allows dose reduction. Without a meaningful reduction in dose or exposure variability, the cost and manufacturing burden may outweigh the benefit.

Modified-release dosage forms

A once-daily product already exists as a key dosing concept for oxaprozin, so a modified-release claim must offer more than convenience. Possible objectives include:

• Lower peak plasma concentration.
• Reduced concentration-related adverse effects.
• Smoother exposure over 24 hours.
• Improved nighttime symptom control.
• Reduced dosing frequency in patients unable to tolerate immediate-release products.

Hydrophilic matrix systems using hypromellose are technically feasible. Multiparticulate systems could provide more flexible release control and reduce sensitivity to tablet geometry. A modified-release product would require robust in vitro-in vivo correlation work and could require clinical studies under a 505(b)(2) strategy.

Gastrointestinal-targeted formulations

Enteric coating could delay release until the small intestine. However, enteric protection does not remove systemic NSAID risks and may not reliably prevent all gastrointestinal injury. A sponsor would need clinically meaningful evidence before making a GI-tolerability claim.

Enteric coating may still have a role in a product designed for patients with upper-gastrointestinal sensitivity, but the strategy is vulnerable to regulatory and commercial criticism if the formulation merely delays, rather than reduces, systemic exposure.

What formulations are protected by future oxaprozin patents?

The strongest patent opportunities are likely to involve a measurable technical feature rather than a generic excipient list.

Potentially defensible claim areas

• Oxaprozin with a defined particle-size distribution.
• Amorphous oxaprozin stabilized by a specified polymer system.
• A specific solid-dispersion ratio and manufacturing process.
• A multiparticulate modified-release system.
• A low-dose formulation enabled by improved bioavailability.
• A tablet with defined dissolution limits across pH conditions.
• A process that reduces impurities or improves batch consistency.
• A formulation designed for a specific patient population or dosing schedule.

Weaker claim areas

• Conventional microcrystalline cellulose and magnesium stearate tablets.
• Routine substitution of one disintegrant for another.
• A standard film coating without a functional release effect.
• Broad claims covering oxaprozin with any pharmaceutically acceptable excipient.
• A method-of-use claim that merely repeats the approved osteoarthritis or rheumatoid arthritis indications.

Patent strength would improve if the formulation produces an unexpected result, such as a substantial dissolution improvement, lower variability, a reduced dose, or a clinically demonstrated tolerability advantage.

What is the Orange Book status of oxaprozin?

The FDA Orange Book remains the controlling source for current listed patents, regulatory exclusivity, and reference-product information. Oxaprozin’s commercial market is primarily generic, and its original patent estate is not a current barrier to ordinary generic entry.

For a new oxaprozin product, Orange Book listing could become commercially important if the product receives approval for a novel formulation or method of use and the sponsor certifies that the patent is eligible for listing. The sponsor would need to distinguish:

• Patents claiming the drug substance.
• Patents claiming the approved formulation.
• Patents claiming the approved method of use.
• Patents that are not eligible for Orange Book listing but may still support other litigation.

A formulation patent with no corresponding approved labeling relevance may have limited Orange Book value even if it has broader commercial significance outside the FDA patent-certification process. [4]

Which companies are challenging oxaprozin exclusivity?

Oxaprozin is already subject to generic competition. Publicly visible competition is expected to come from generic manufacturers and contract manufacturers rather than from biosimilar developers.

The relevant competitive groups are:

Competitor type	Strategic position
Established generic manufacturers	Compete on price, supply reliability, and wholesaler access
Specialty generic companies	May pursue modified release or difficult-to-formulate versions
Contract development and manufacturing organizations	Enable low-capital reformulation programs
Branded NSAID manufacturers	Compete through alternative active ingredients and combination products
Digital or specialty pharmacy distributors	May create adherence or packaging differentiation
Biosimilar developers	Not relevant to oxaprozin

Paragraph IV litigation is not a central current risk for conventional oxaprozin tablets because the foundational exclusivity has expired. It would become relevant if a sponsor listed a new formulation or method-of-use patent and a generic applicant filed a Paragraph IV certification against that patent.

What generic launch risks exist for oxaprozin?

A conventional generic launch faces low scientific risk but high commercial risk.

Regulatory risks

The principal FDA issues include dissolution similarity, bioequivalence, dose proportionality, manufacturing consistency, and tablet-size acceptability. A formulation that uses enhanced solubility technology may not fit comfortably within a simple ANDA strategy if it changes exposure or release behavior.

Manufacturing risks

High-dose tablets create pressure on:

• Blend uniformity.
• Compression force.
• Tablet weight.
• Capping and lamination.
• Coating time.
• Packaging volume.
• Supply of high-quality active pharmaceutical ingredient.

A process patent covering particle engineering, impurity control, or a specialized dispersion could create a stronger manufacturing barrier than a routine composition patent.

Commercial risks

Oxaprozin has limited pricing power because physicians can choose other generic NSAIDs. A differentiated product must justify its price through a clear advantage in dosing, tolerability, adherence, or pharmacokinetic consistency.

How does oxaprozin compare with competing NSAIDs?

Oxaprozin’s principal advantage is once-daily dosing. Its principal disadvantages are high dose load, mature generic competition, and the class-wide safety risks of NSAIDs.

Product	Typical commercial differentiation	Excipient opportunity
Oxaprozin	Once-daily dosing and long duration	Dose reduction, modified release, swallowability
Naproxen	Broad generic availability and established use	GI-focused delivery, combination products
Meloxicam	Lower-dose once-daily administration	Pediatric liquid, dispersible, modified release
Celecoxib	COX-2 selectivity and capsule delivery	Abuse-resistant packaging, combination products
Diclofenac	Multiple routes and dosage forms	Topical, oral, transdermal, localized delivery
Ibuprofen	Very large generic market and multiple strengths	Pediatric, liquid, fast-dissolve, combination products

Oxaprozin is less attractive than low-dose NSAIDs for a simple tablet innovation because its 600 mg or 1200 mg dose creates a physical formulation constraint. It may be more attractive for a technology that reduces dose or improves exposure consistency.

What licensing deals could support oxaprozin commercialization?

No major current licensing structure is required to commercialize standard generic oxaprozin. A licensing transaction would make more sense for a differentiated platform.

Potential deal structures include:

• In-license of a solid-dispersion or particle-engineering platform.
• Regional licensing of a modified-release formulation.
• Supply and development agreement with a CDMO.
• Co-development of a 505(b)(2) product.
• Rights to a validated manufacturing process.
• Commercial partnership with a specialty pharmacy focused on adherence or chronic pain.

The most bankable transaction would link the licensed technology to a measurable product advantage and a patent position extending well beyond the cost of development.

How strong is the oxaprozin patent estate?

The legacy oxaprozin patent estate is commercially weak because the drug is generic and the original exclusivity period has ended. A new estate could be moderately strong if it protects a technically difficult formulation with a demonstrated clinical or pharmacokinetic advantage.

Estate type	Relative strength
Conventional immediate-release tablet	Low
Particle-size-controlled tablet	Low to moderate
Amorphous solid dispersion	Moderate
Dose-reduced formulation	Moderate to strong if clinically validated
Modified-release product	Moderate, dependent on claims and data
New route of administration	Potentially strong, but development-intensive
Manufacturing impurity-control process	Moderate outside Orange Book litigation
New indication	Variable and dependent on clinical differentiation

The most defensible strategy is to combine composition claims, process claims, dissolution specifications, and clinically relevant method-of-use claims. One narrow formulation patent should not be treated as a complete barrier to design-around.

What commercial opportunities exist for oxaprozin?

The strongest opportunities are selective rather than broad.

1. Dose-reduced oral product

A formulation that increases bioavailability could reduce the active dose, tablet burden, and packaging requirements. This is the highest-value technical concept, but it requires convincing pharmacokinetic and clinical data.

2. Patient-friendly dosage form

A smaller tablet, orally disintegrating tablet, sprinkle formulation, or liquid suspension could target older patients and patients with dysphagia. High-dose loading remains a constraint, and taste masking would be essential for liquid or orally disintegrating products.

3. Modified-release product

A genuinely differentiated 24-hour exposure profile could support a 505(b)(2) product. The commercial case would depend on lower peak-related intolerance or improved symptom control, not dosing frequency alone.

4. Combination product

A fixed-dose combination with gastroprotective therapy could create a branded product concept, but it would face clinical, regulatory, and safety complexities. The combination would need to demonstrate adherence or outcome advantages over separate products.

5. Emerging-market supply platform

A low-cost, robust tablet with stable supply may be commercially viable in markets where generic availability is inconsistent. The opportunity depends on local registration, procurement contracts, pricing, and manufacturing economics rather than U.S. patent exclusivity.

Key Takeaways

• Oxaprozin is a mature generic NSAID with no meaningful remaining legacy exclusivity.
• Conventional immediate-release tablets offer limited patent and pricing potential.
• The best excipient opportunities involve dissolution enhancement, dose reduction, modified release, or patient-friendly delivery.
• High dose load is the central formulation constraint.
• A solid-dispersion or particle-engineering platform could create stronger patent value than routine excipient substitution.
• A new product would likely require a 505(b)(2) strategy if it departs materially from the reference tablet.
• Paragraph IV risk is limited for ordinary oxaprozin generics but could emerge against newly listed formulation or method-of-use patents.
• Biosimilar competition is irrelevant because oxaprozin is a small molecule.
• Commercial success depends on a measurable advantage over low-cost generic tablets and competing NSAIDs.
• Manufacturing-process patents may be more valuable for cost and supply protection than for Orange Book-based litigation.

FAQs

Can oxaprozin be formulated as an oral suspension?

Yes. An oral suspension could address swallowing difficulty, but the high dose, taste, sedimentation, dose uniformity, preservative system, and chemical stability would require substantial development work.

Is an oxaprozin transdermal product commercially attractive?

Potentially, but the required daily dose and skin permeation properties create major feasibility risks. A transdermal product would need a strong exposure and tolerability advantage over oral generics.

Would a new oxaprozin tablet receive new chemical-entity exclusivity?

No. A conventional reformulation would not receive NCE exclusivity. Regulatory protection would depend on the selected FDA pathway, clinical evidence, and any applicable formulation or method-of-use exclusivity.

Can excipient substitution alone support an oxaprozin patent?

Usually not. A patent based only on routine excipient selection would face significant obviousness risk unless the formulation produces an unexpected and reproducible technical result.

What is the most attractive oxaprozin development path?

A dose-reduced, dissolution-enhanced product with a defined pharmacokinetic or tolerability advantage is the strongest strategic concept. It offers a clearer basis for patent claims, clinical differentiation, and premium pricing than a standard generic tablet.

References

1. U.S. Food and Drug Administration. (2023). Oxaprozin tablets prescribing information. FDA/DailyMed labeling database.

2. U.S. Food and Drug Administration. (2023). Applications covered by section 505(b)(2). FDA Guidance for Industry.

3. National Library of Medicine. (2024). DailyMed: Oxaprozin tablet product labels. U.S. National Library of Medicine.

4. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. Orange Book.