U.S. Patent 11,090,280: Naproxen Sodium Softgel Claims, Exclusivity Scope, and Patent Landscape

U.S. Patent No. 11,090,280 covers liquid soft gelatin capsules containing a naproxen salt, an organic-acid deionizing agent, polyethylene glycol, and one or more solubilizers. The strongest commercial claim is claim 13, which specifically requires naproxen sodium and a defined solubilizer group. The principal technical limitation is the use of acetic, propionic, pyruvic, or lactic acid at 0.2 to 1.0 mole equivalents per mole of naproxen salt.

The patent is directed to formulation composition, treatment, and manufacturing claims. It does not broadly cover all naproxen capsules, all naproxen sodium products, or all liquid NSAID formulations.

What does U.S. Patent 11,090,280 protect?

The patent protects a softgel formulation with four mandatory components:

Required element	Scope
Naproxen active	A naproxen salt; claim 13 narrows this to naproxen sodium
Deionizing agent	Acetic acid, propionic acid, pyruvic acid, or lactic acid
Deionizing-agent ratio	0.2 to 1.0 mole equivalents per mole of naproxen salt
Polyethylene glycol	Required, with dependent claims covering 10% to 80% by weight and molecular weights of 300 to 1,500
Solubilizer	Required; dependent claims identify glycerin, polyvinylpyrrolidone, propylene glycol, or combinations

The term “comprising” makes the composition claims open-ended. A product may contain additional excipients and remain within the claim if every required element is present. Claim 8 expressly identifies additional excipient categories, including plasticizers, crystallization inhibitors, wetting agents, bulk-filling agents, bioavailability enhancers, solvents, dyes, preservatives, and surfactants. (U.S. Patent No. 11,090,280, claims 1-22.)

The patent therefore targets a formulation architecture rather than a single finished-product trade dress or a particular capsule size.

How are the claims organized?

Claim 1: Broadest composition claim

Claim 1 requires a soft gelatin capsule containing a fill material with:

A naproxen salt;
A listed organic-acid deionizing agent at 0.2 to 1.0 mole equivalents;
Polyethylene glycol; and
One or more solubilizers.

The claim does not require naproxen sodium specifically. A different naproxen salt could theoretically satisfy claim 1 if it meets the remaining limitations.

Claim 1 also does not require:

Water;
A liquid fill;
A particular polyethylene glycol molecular weight;
A particular solubilizer;
A particular manufacturing temperature; or
A specific therapeutic dose.

Those limitations appear in dependent claims.

Claim 13: Narrower naproxen sodium composition

Claim 13 is an independent composition claim requiring:

Naproxen sodium;
Acetic, propionic, pyruvic, or lactic acid;
The same 0.2 to 1.0 mole-equivalent ratio;
Polyethylene glycol; and
Glycerin, polyvinylpyrrolidone, propylene glycol, or combinations thereof.

Claim 13 is commercially important because it maps more closely to conventional naproxen sodium softgel products. It eliminates some breadth available under claim 1 but provides a more specific formulation combination.

Claims 10 and 20: Treatment claims

Claims 10 and 20 cover treating pain, inflammation, or fever by administering the claimed capsule. These claims depend on the composition limitations of claim 1 and claim 13, respectively.

A method-of-treatment claim is not infringed merely because a product contains naproxen sodium. The administered product must satisfy the incorporated composition limitations. The treatment must also involve one of the claimed indications or symptom categories.

Claim 11: Manufacturing method

Claim 11 covers:

Mixing the naproxen salt, deionizing agent, polyethylene glycol, and solubilizer; and
Encapsulating the mixture in a softgel capsule.

Claim 12 narrows the mixing step to 50°C to 70°C.

Claim 11 does not require the manufacturer to use a particular mixing sequence, residence time, equipment type, or encapsulation machine. A manufacturer using a different process may still infringe if the process performs the claimed steps under ordinary claim-construction principles.

What formulations are protected by U.S. Patent 11,090,280?

The protected formulation space can be divided into three tiers.

Formulation tier	Relevant claims	Key limitations
Broad naproxen-salt softgel	1-12	Naproxen salt, listed acid, PEG, solubilizer
Naproxen sodium softgel	13-20	Naproxen sodium plus defined acid and solubilizer group
Lactic-acid species	21-22	Claim 1 or 13 formulation with lactic acid

The lactic-acid claims are especially narrow. Claims 21 and 22 remove three of the four possible acids and require lactic acid. A commercial product using lactic acid would face a more direct claim comparison than a product using acetic acid or another permitted acid.

Water limitation

Claims 3 and 16 require water at 1% to 18% by weight. A formulation with no water, or water below 1%, would not meet those dependent claims, although it could still fall within claim 1 or claim 13.

The water range creates a measurable formulation boundary. Analytical testing would typically focus on water content in the fill material, not merely the total capsule.

Polyethylene glycol limitation

Claims 4, 5, 14, and 15 narrow the PEG limitation:

PEG at 10% to 80% by weight; and
PEG molecular weight from 300 to 1,500.

A formulation using PEG outside that molecular-weight range could still potentially fall within the independent claims because claims 1 and 13 require PEG but do not impose the dependent-claim molecular-weight restriction.

Solubilizer limitation

Claims 6 and 18 require 1% to 10% solubilizer by weight. Claims 7 and 13 identify glycerin, polyvinylpyrrolidone, and propylene glycol.

The independent claims use broader “one or more solubilizers” language. A formulation using a solubilizer outside the named dependent-claim group may still present risk under claim 1, depending on whether the ingredient qualifies as a solubilizer under the patent’s specification and claim construction.

How strong is the patent estate for naproxen softgels?

The estate appears strongest against products that combine all of the following:

Naproxen sodium;
A listed organic acid;
The 0.2 to 1.0 mole-equivalent ratio;
PEG;
Glycerin, propylene glycol, or polyvinylpyrrolidone; and
A soft gelatin capsule.

The estate is weaker against products that use a different delivery system, different acid chemistry, or a non-PEG vehicle.

Key design-around variables

Design-around variable	Potential effect
Use naproxen free acid rather than a naproxen salt	May avoid the naproxen-salt limitation but raises solubility and stability issues
Use a non-listed acid	May avoid the specific deionizing-agent Markush group
Omit PEG	Directly targets a required limitation
Use a hard capsule, tablet, suspension, or liquid-filled two-piece capsule	May avoid the soft gelatin capsule limitation
Use an alternative solubilizer	May avoid dependent claims but not necessarily claim 1
Alter the acid ratio to below 0.2 or above 1.0 equivalents	Potentially avoids the ratio limitation, subject to measurement and claim construction
Use a non-liquid fill	May avoid claims requiring liquid fill, but not claims 1 or 13
Use a different manufacturing sequence	May avoid claim 11 if the process does not perform the claimed mixing and encapsulation steps

No single design-around is automatically sufficient. A product may avoid a dependent claim while remaining within an independent claim.

Does the patent cover naproxen tablets or ordinary naproxen products?

Generally, no. The composition claims require a soft gelatin capsule. Conventional tablets, caplets, powders, hard-shell capsules, and ordinary suspensions would not satisfy that dosage-form limitation.

The treatment claims are narrower than a general method-of-treating-pain claim because they require administration of the claimed softgel composition. A naproxen tablet used to treat pain would not ordinarily meet claims 10 or 20.

The patent also does not claim naproxen as a chemical compound, naproxen sodium generally, or the therapeutic use of naproxen independent of the softgel formulation.

What is the patent’s manufacturing and formulation barrier?

The technical barrier is the combination of acid-mediated deionization with a PEG-based softgel fill. Naproxen sodium is an ionized salt. An organic acid can alter the ionic environment and potentially influence solubility, crystallization, fill uniformity, and release behavior. PEG provides a liquid or semi-liquid vehicle, while glycerin, propylene glycol, or polyvinylpyrrolidone can support solubilization and formulation stability.

The claimed acid range is expressed on a molar basis rather than only as a weight percentage. That matters because acetic, propionic, pyruvic, and lactic acids have different molecular weights. An accused product should be evaluated using:

[ \text{Mole equivalents} = \frac{\text{moles of organic acid}}{\text{moles of naproxen salt}} ]

The principal manufacturing risks are:

Maintaining the acid ratio within the claimed range;
Preventing naproxen or naproxen acid from crystallizing;
Controlling water content;
Achieving a homogeneous fill;
Maintaining capsule-shell compatibility; and
Demonstrating that the finished fill retains the claimed composition after manufacturing.

Claim 12 creates a separate process risk for manufacturers mixing at 50°C to 70°C. A manufacturer may avoid claim 12 by using another temperature, but that does not avoid composition claims 1 or 13.

What is the Orange Book status of U.S. Patent 11,090,280?

Patent 11,090,280 is a formulation patent, not an automatic Orange Book right. Orange Book listing depends on submission by the applicable NDA holder and acceptance by FDA under the Hatch-Waxman listing framework. FDA identifies patents and exclusivity associated with approved drug products in the Approved Drug Products with Therapeutic Equivalence Evaluations publication. (FDA, 2024a.)

A patent number by itself does not establish that the patent is listed for a particular NDA. The patent claims also do not identify an NDA, reference-listed drug, applicant, dosage strength, or approved product code.

The practical consequences are:

Orange Book listing cannot be inferred solely from the patent claims;
Paragraph IV exposure depends on whether an ANDA applicant must address a listed patent;
A non-listed patent may still create infringement risk under 35 U.S.C. § 271;
A patent may be relevant to a marketed product without being an Orange Book-listed patent.

When does U.S. Patent 11,090,280 lose exclusivity?

The claims supplied do not state the patent’s earliest effective filing date, priority chain, patent-term adjustment, or terminal disclaimer. The expiration date therefore cannot be derived from the claims alone.

For a utility patent, the ordinary term is generally 20 years from the earliest effective nonprovisional filing date, subject to patent-term adjustment, patent-term extension, terminal disclaimers, and statutory exceptions. (35 U.S.C. §§ 154, 156.) FDA regulatory exclusivity is separate from patent term.

The relevant exclusivity dates are therefore distinct:

Right	Governing source	Effect
Patent term	35 U.S.C. § 154	Excludes unauthorized making, using, selling, offering for sale, or importing
Patent-term extension	35 U.S.C. § 156	May extend eligible drug patent term
Regulatory exclusivity	FD&C Act and FDA regulations	Restricts certain abbreviated applications for defined periods
Orange Book listing	FDA Orange Book rules	Requires patent certification or statement in applicable ANDA circumstances

A patent expiration date should be taken from the USPTO patent record and adjusted for any terminal disclaimer or patent-term adjustment. It should not be estimated from the issue date.

Which companies are challenging U.S. Patent 11,090,280?

The patent claims alone do not identify an ANDA filer, Paragraph IV notice, district-court case, inter partes review, post-grant review, settlement, or licensee.

A Paragraph IV challenge would require an ANDA applicant to assert that the patent is invalid, unenforceable, or not infringed. Under 21 U.S.C. § 355(j)(2)(A)(vii)(IV), the filing of a Paragraph IV certification can trigger patent litigation under 35 U.S.C. § 271(e)(2). The patent’s formulation focus means a challenger would likely concentrate on:

Anticipation by prior softgel formulations;
Obviousness based on naproxen sodium, PEG, organic acids, and solubilizers;
Whether the acid ratio was expressly or inherently disclosed;
Whether “deionizing agent” has adequate written-description support;
Whether the claims provide an enabling disclosure across all listed acids and solubilizers; and
Whether the accused product contains the required acid and PEG amounts.

A generic applicant could also pursue a non-infringement position by using a different acid, vehicle, capsule type, or formulation ratio.

What prior-art issues affect validity?

The likely prior-art pressure points are predictable from the claim structure.

Anticipation

A single reference would need to disclose all limitations in one formulation, including:

Soft gelatin capsule;
Naproxen salt;
One of the four listed acids;
0.2 to 1.0 mole equivalents;
PEG; and
Solubilizer.

A reference disclosing naproxen sodium softgels without the acid ratio may not anticipate claim 1 or claim 13, although it could contribute to an obviousness challenge.

Obviousness

An obviousness challenge could combine:

Known naproxen sodium softgel formulations;
Organic acids used to modify salt form or ionization;
PEG liquid vehicles;
Glycerin or propylene glycol solubilizers; and
Routine optimization of acid concentration.

The strongest patentability defense would likely rely on an unexpected formulation result tied to the claimed acid ratio, such as improved physical stability, reduced crystallization, improved fill uniformity, or enhanced release. Under 35 U.S.C. § 103, the commercial product must be evaluated against the combination of prior-art teachings and the motivation to select the claimed ranges.

Claim construction

The terms “deionizing agent,” “solubilizer,” and “fill material” may become central in litigation. The patent specification, prosecution history, and technical evidence would control their meaning. A formulation company should not assume that an ingredient escapes the claim merely because the product label uses a different functional description.

How does this patent compare with ordinary naproxen patent estates?

Estate type	Typical protected subject matter	Relationship to Patent 11,090,280
Compound patent	Naproxen or related chemical entity	Separate and generally much broader, if still enforceable
Salt patent	Naproxen sodium or another salt	May overlap with the active ingredient but not necessarily the softgel
Formulation patent	PEG, acid, solubilizer, capsule architecture	Directly relevant
Method-of-use patent	Pain, inflammation, fever, or specific disease	Claims 10 and 20 are formulation-linked use claims
Manufacturing patent	Mixing, heating, encapsulation	Claim 11 and claim 12
Regulatory exclusivity	FDA approval-based protection	Separate from this patent

The patent is best characterized as a formulation and process patent with method-of-treatment claims. It does not replace or necessarily overlap with patents covering naproxen chemistry, enteric delivery, sustained release, or unrelated dosage forms.

What generic launch risks exist?

A generic or private-label manufacturer faces the highest risk if its product is a liquid naproxen sodium softgel using an organic acid and PEG-based vehicle. The risk analysis should focus on the finished fill rather than only the product label.

A launch review should test:

Naproxen salt identity;
Organic-acid identity;
Acid-to-naproxen molar ratio;
PEG presence, concentration, and molecular weight;
Solubilizer identity and concentration;
Water content;
Capsule-shell composition;
Manufacturing temperature and process sequence; and
Intended use and labeling.

The strongest non-infringement position would generally involve a non-softgel dosage form or a formulation that omits PEG or uses no listed acid. A formulation that merely changes the percentage of glycerin while retaining all independent-claim elements may not avoid claim 1 or claim 13.

What are the licensing and commercial implications?

The patent claims do not identify a licensee, assignment, collaboration, or settlement agreement. A license cannot be inferred from the existence of a patent or from a product’s similarity to the claimed formulation.

Commercial exposure depends on the extent to which revenue is concentrated in the covered dosage form. A company selling only tablets would face limited direct exposure. A company selling liquid naproxen sodium softgels with the claimed excipient architecture could face product redesign, licensing, litigation, or delayed generic entry.

Because the patent is formulation-specific, its value is likely highest when:

The claimed softgel provides a commercially important dosage-form advantage;
The formulation is difficult to redesign without losing solubility or stability;
The patent is listed against an approved NDA;
The patent has surviving claims after prosecution or post-grant review; or
The patent is supported by manufacturing know-how not apparent from the claims.

Key Takeaways

U.S. Patent 11,090,280 covers specific naproxen softgel formulations, not naproxen products generally.
Claim 1 is the broadest composition claim and requires a naproxen salt, listed organic acid, PEG, and solubilizer.
Claim 13 is the principal naproxen sodium claim.
Claims 21 and 22 narrow the formulation to lactic acid.
The 0.2 to 1.0 mole-equivalent acid range is a central infringement and validity issue.
PEG is mandatory in the independent composition claims.
Water, PEG concentration, PEG molecular weight, solubilizer concentration, liquid fill, and heating temperature are mostly dependent-claim limitations.
The patent does not establish Orange Book listing, Paragraph IV litigation, licensing, settlement, or generic challenges.
A patent expiration date requires the priority and term-adjustment record, not merely the issue number.
The most credible design-around routes involve changing the dosage form, omitting PEG, using a non-listed acid, or moving outside the claimed acid ratio.

FAQs

Does a naproxen sodium softgel automatically infringe U.S. Patent 11,090,280?

No. The product must also contain the claimed organic acid within the specified molar ratio, PEG, and the required solubilizer elements. A naproxen sodium softgel lacking one of those limitations may avoid the independent composition claims.

Does lactic acid create special infringement risk?

Yes. Claims 21 and 22 expressly identify lactic acid as the deionizing agent. A product using lactic acid within the 0.2 to 1.0 mole-equivalent range presents a direct comparison to those claims.

Can a manufacturer avoid the patent by using a hard capsule?

A hard capsule would generally avoid the soft gelatin capsule limitation, assuming the claim is construed as requiring that dosage form. The manufacturer must still evaluate other patents covering the underlying formulation or delivery system.

Are glycerin and propylene glycol interchangeable under the claims?

Both are expressly identified in dependent claim 7 and claim 13. Substituting one for the other does not by itself avoid the claims. The formulation must be assessed against every limitation, including PEG and the organic-acid ratio.

Does a different manufacturing temperature avoid the patent?

A different temperature may avoid claim 12, which requires mixing at 50°C to 70°C. It does not necessarily avoid composition claims 1 or 13, or manufacturing claim 11, which does not impose the claim 12 temperature range.

References

U.S. Patent No. 11,090,280, claims 1-22. United States Patent and Trademark Office.
Federal Food, Drug, and Cosmetic Act, 21 U.S.C. § 355.
Hatch-Waxman Amendments, 21 U.S.C. § 355(j).
Patent Act, 35 U.S.C. §§ 102, 103, 112, 154, 156, 271.
U.S. Food and Drug Administration. (2024a). Approved drug products with therapeutic equivalence evaluations: Orange Book. FDA.
U.S. Patent and Trademark Office. (2024). Patent Center. USPTO.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Bionpharma	NAPROXEN SODIUM	naproxen sodium	CAPSULE;ORAL	021920-001	Feb 17, 2006		OTC	Yes	Yes	11,090,280	⤷ Start Trial	Y			TEMPORARY RELIEF OF MINOR ACHES AND PAINS	⤷ Start Trial
Bionpharma	NAPROXEN SODIUM	naproxen sodium	CAPSULE;ORAL	021920-001	Feb 17, 2006		OTC	Yes	Yes	11,090,280	⤷ Start Trial	Y			TEMPORARY REDUCTION OF FEVER	⤷ Start Trial
>Applicant	>Tradename	>Generic Name	>Dosage	>NDA	>Approval Date	>TE	>Type	>RLD	>RS	>Patent No.	>Patent Expiration	>Product	>Substance	>Delist Req.	>Patented / Exclusive Use	>Submissiondate

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Canada	2600023	⤷ Start Trial
China	101166520	⤷ Start Trial
China	102940887	⤷ Start Trial
Cyprus	1118321	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 11,090,280

Which drugs does patent 11,090,280 protect, and when does it expire?

Summary for Patent: 11,090,280