US Patent 10,293,052: Claim Scope, Eosinophilic Esophagitis Formulation Coverage, and Patent Landscape

US Patent 10,293,052 protects a stable, mucoadhesive oral liquid corticosteroid formulation designed to retain drug on the esophageal surface. The independent claim is formulation-centered and requires four core technical features: a topical corticosteroid, liquid vehicle, specified maltodextrin concentration, and specified carboxymethyl cellulose concentration. It also requires demonstrated esophageal adhesion, chemical and physical stability, and uniformity for at least one day.

The patent has its strongest commercial relevance for swallowed budesonide or fluticasone formulations used to treat eosinophilic esophagitis and other esophageal inflammatory conditions. The claims do not cover every oral corticosteroid suspension. A potentially infringing product must satisfy the compositional, concentration, performance, and stability limitations of claim 1, or fall within a dependent claim.

What does US Patent 10,293,052 claim?

Independent claim 1

Claim 1 requires a composition containing:

Required element	Claim limitation
Dosage form	Stable oral pharmaceutical composition
Therapeutic purpose	Treating or alleviating esophageal inflammation or symptoms
Active ingredient	Topically active corticosteroid
Vehicle	Liquid vehicle
Maltodextrin	About 0.05 g to about 2 g per mL
Carboxymethyl cellulose	About 1 mg to about 150 mg per mL
Esophageal retention	At least 10% adheres to the esophagus for at least 15 seconds
Stability	Chemically and physically stable
Uniformity	Remains substantially uniform for at least one day

The claim is cumulative. Each limitation must be satisfied for literal infringement. A formulation with budesonide, maltodextrin, and CMC may still avoid claim 1 if it fails the specified adhesion test, falls outside the concentration ranges, or does not meet the stability and uniformity requirements.

The adhesion requirement is important. The claim is not limited solely by excipient identity. It also requires a functional result after administration. This gives the patent a performance-based scope that may reach formulations with different excipient ratios if they produce the claimed retention and satisfy the remaining limitations.

Dependent claims 2 and 3

Claims 2 and 3 narrow the corticosteroid to:

Budesonide
Fluticasone propionate

These claims create direct coverage for the two most commercially relevant topical corticosteroids used in swallowed esophageal therapy. Claim 2 is likely the more commercially significant claim because budesonide is the active ingredient in FDA-approved Eohilia, a budesonide oral suspension approved for eosinophilic esophagitis in adults and pediatric patients 11 years and older [2].

Claim 3 covers fluticasone propionate formulations, including products administered orally after delivery from an inhaler or other device if the resulting composition meets the claim limitations. The claim does not cover every swallowed fluticasone product because the maltodextrin, CMC, liquid, stability, and adhesion requirements remain applicable.

How broad is the formulation coverage?

The practical scope depends on whether the claim limitations are interpreted as structural requirements, performance requirements, or both.

Structural scope

Claim 1 covers a formulation with:

Any topically active corticosteroid
Any liquid vehicle
Maltodextrin within the stated concentration range
CMC within the stated concentration range

The claim does not require a particular pH, viscosity, dosage volume, preservative, sweetener, flavor, buffer, or container. Those omissions broaden the structural scope.

The claim also does not expressly require a particular dose of corticosteroid. A product containing 0.5 mg, 1 mg, 2 mg, or another amount could potentially fall within the claim if the formulation otherwise meets the required limitations.

Functional scope

The composition must adhere to the esophagus for at least 15 seconds. This requirement distinguishes the claimed product from conventional low-viscosity oral liquids that rapidly transit into the stomach.

Claims 4 and 5 expand the drug-retention concept by requiring at least 10% of the corticosteroid to adhere to, or adhere to and be absorbed by, the esophagus. Claims 6 through 8 impose comparative performance tests against specified control compositions.

These limitations create potential evidentiary issues in litigation. Infringement analysis may require:

Testing the accused product after oral administration.
Measuring the amount of formulation or corticosteroid remaining on the esophageal surface after 15 seconds.
Reconstructing the control formulation or viscosity standard.
Confirming the concentration of maltodextrin and CMC.
Establishing that the product remains uniform for at least one day.

What do claims 4 through 8 add?

Claim	Additional limitation	Commercial significance
4	At least 10% of corticosteroid adheres for at least 15 seconds	Focuses on drug retention rather than total formulation retention
5	At least 10% of corticosteroid adheres to or is absorbed by the esophagus	Broader retention or uptake metric
6	Greater formulation adhesion than a specified dextrose/maltodextrin/sucralose control	Requires comparative testing
7	Greater corticosteroid adhesion or absorption than the specified control	Compares drug delivery performance
8	Greater adhesion or absorption than a 1 cP control at 25°C and 13.2 sec⁻¹	Targets the effect of viscosity and formulation structure

Claims 6 and 7 are technically narrower because they require comparison with a defined control containing aqueous formulation and a dextrose, maltodextrin, and sucralose mixture. Claim 8 uses a rheological benchmark rather than the detailed sweetener control.

These claims may be valuable where a competitor argues that it uses different excipients. A product could still face risk if it produces superior esophageal retention relative to the specified control and satisfies claim 1.

What formulations are protected by claims 9 through 12?

Second maltodextrin

Claim 9 requires a second maltodextrin that increases viscosity. Claim 10 adds that the second maltodextrin does not substantially affect mucoadhesion.

These claims appear directed to a formulation strategy separating two functions:

One component contributes to the required maltodextrin content.
A second maltodextrin component increases viscosity without materially changing mucoadhesion.

The claims may raise construction issues because claim 1 already requires maltodextrin. The phrase “a second maltodextrin” supports an interpretation requiring distinguishable maltodextrin components or separate functional roles, although the patent specification and prosecution history would control how the limitation is applied.

Mucoadhesive and viscosity-enhancing agents

Claim 11 adds a mucoadhesive agent. Claim 12 adds a viscosity-enhancing agent. These claims are broad because they do not identify a particular agent.

Potentially relevant agents could include cellulose derivatives, xanthan gum, carbomers, alginates, polyvinylpyrrolidone, or other polymers, subject to the specification and claim construction. CMC is already required by claim 1, so claim 11 likely covers compositions containing an additional mucoadhesive component or a mucoadhesive system beyond the baseline CMC requirement.

When does US Patent 10,293,052 lose exclusivity?

The patent grant date was May 19, 2020. The enforceable term cannot be determined from the claims alone because the expiration date depends on the earliest effective nonprovisional filing date, any terminal disclaimer, patent-term adjustment, and possible patent-term extension.

The relevant term analysis is:

Exclusivity component	Relevance
Patent term	Generally measured from the earliest effective nonprovisional filing date
Patent-term adjustment	May extend the term for USPTO prosecution delay
Terminal disclaimer	May shorten the term or tie it to another patent
Patent-term extension	Potentially available for qualifying regulatory review
FDA pediatric exclusivity	May add six months to qualifying regulatory exclusivity or listed patent protection
Orphan-drug exclusivity	Relevant only if the product has an applicable orphan designation

A definitive expiration date requires review of the complete patent family, continuity data, USPTO Patent Center records, and any Orange Book listing. The claims excerpt does not establish those dates.

What is the Orange Book status of US Patent 10,293,052?

The claims are relevant to an FDA-approved budesonide oral suspension, but the claims excerpt does not establish whether US 10,293,052 is listed in the Orange Book for a specific reference product.

Orange Book relevance depends on whether the patent claims:

The active ingredient;
The approved formulation;
The approved method of use; or
A drug-delivery system used with the approved product.

For an oral liquid formulation, the patent would generally be most relevant as a formulation patent. A listed formulation patent can require an ANDA applicant to provide a Paragraph IV certification if the applicant seeks approval before patent expiration and does not accept a Paragraph III certification.

The FDA’s Orange Book identifies patents and exclusivities associated with approved drug products, but listing status is product-specific and may change through updates, delistings, corrections, or regulatory submissions [3].

What Paragraph IV challenges could target the patent?

A generic applicant could challenge the patent through a Paragraph IV certification under section 505(j) of the Federal Food, Drug, and Cosmetic Act. The principal invalidity and noninfringement theories would likely involve the following issues.

Anticipation

A challenger would need to identify a single prior-art reference disclosing every claim 1 limitation, including:

The specified maltodextrin concentration;
The specified CMC concentration;
Esophageal adhesion of at least 10% for at least 15 seconds;
Chemical and physical stability; and
At least one day of substantial uniformity.

The adhesion and stability limitations may make anticipation more difficult unless a prior reference expressly reports those results.

Obviousness

Obviousness would likely be the central validity challenge. A challenger could combine prior art concerning:

Swallowed budesonide or fluticasone therapy;
Maltodextrin as a bulking or viscosity-modifying excipient;
CMC as a mucoadhesive or suspending agent;
Esophageal retention;
Stable aqueous corticosteroid suspensions; and
Comparative viscosity or adhesion testing.

The patent holder would likely rely on unexpected retention, improved uniformity, longer residence time, or a specific relationship between viscosity and mucoadhesion.

Indefiniteness

Potential indefiniteness issues include:

“About” in the concentration ranges;
“Topically active corticosteroid”;
“Chemically and physically stable”;
“Substantially uniform”;
“Does not substantially affect” mucoadhesion; and
The method used to measure 10% adhesion after 15 seconds.

These terms may be supported by experimental protocols in the specification. Their enforceability depends heavily on whether the patent identifies reproducible test methods and objective boundaries.

Written description and enablement

The broad genus in claim 1 covers any topically active corticosteroid, but claims 2 and 3 identify budesonide and fluticasone propionate. A challenger could argue that the disclosure does not enable the full scope of all corticosteroids, all liquid vehicles, all concentration combinations, and all formulations satisfying the adhesion limitation without undue experimentation.

How does the patent compare with competing esophageal corticosteroid strategies?

Strategy	Typical active ingredient	Delivery concept	Relationship to US 10,293,052
Budesonide oral suspension	Budesonide	Swallowed liquid designed for esophageal contact	Closest commercial overlap
Budesonide viscous slurry	Budesonide	Extemporaneous or compounded mucoadhesive suspension	May overlap if maltodextrin and CMC ranges are met
Swallowed inhaled corticosteroid	Fluticasone propionate	Inhaler actuation followed by swallowing	Less likely to meet the claimed liquid-composition limitations
Orodispersible or esophageal tablet	Budesonide or other steroid	Solid dosage form dissolving in the esophagus	Outside claim 1 if no liquid vehicle
Enteric oral corticosteroid	Various	Gastrointestinal delivery	Generally outside the topical esophageal purpose and adhesion requirements

The patent is narrower than a broad method-of-treatment patent but potentially stronger against liquid formulation competitors. A tablet, capsule, dry powder, or inhaled product may avoid the central liquid-composition limitations. A competing oral suspension would face greater risk.

What manufacturing and intellectual-property barriers matter?

The principal technical barriers are formulation reproducibility and performance testing. A manufacturer must control:

CMC grade and substitution characteristics;
Maltodextrin molecular-weight profile;
Polymer hydration;
Particle settling;
Redispersibility;
Viscosity at relevant shear rates;
Corticosteroid uniformity;
Preservative compatibility;
Container closure performance; and
Esophageal retention after administration.

A formulation can fall within the literal concentration ranges but fail the claimed stability or adhesion limitation. Conversely, a formulation using a different commercial brand of CMC or maltodextrin may still present risk if it produces the claimed results.

The manufacturing process itself is not directly claimed in the supplied claims. The patent therefore does not block every process for making a corticosteroid suspension. Its primary barrier is the finished composition.

What litigation and settlement risks should be monitored?

A complete litigation conclusion cannot be drawn from the claims excerpt. For commercial diligence, the relevant records are:

USPTO Patent Center prosecution history;
Patent family and continuation applications;
FDA Orange Book listing history;
FDA Paragraph IV litigation records;
District court and Federal Circuit dockets;
ANDA notice letters;
Any settlement agreements;
Patent-term adjustment and terminal-disclaimer records; and
Product labeling and formulation changes.

A settlement involving a generic applicant could establish an authorized launch date before patent expiration. The absence of a public case does not establish the absence of a Paragraph IV notice, because notice letters may precede publicly filed litigation.

What is the generic launch risk?

Generic launch risk depends on the product’s formulation and regulatory pathway.

Low-to-moderate risk for non-liquid products

A conventional capsule, tablet, inhaled product, or nonmucoadhesive dosage form may avoid claim 1 because it lacks the required liquid vehicle, maltodextrin, CMC, or adhesion characteristics.

Higher risk for liquid budesonide products

A liquid budesonide product using maltodextrin and CMC within the claimed ranges presents the closest technical risk. The applicant would likely need to address:

Literal infringement;
Adhesion testing;
Stability and uniformity;
Claim construction of “about”;
Potential invalidity based on prior art; and
Any Orange Book listing for the reference product.

Regulatory alternatives

A 505(b)(2) applicant could pursue a different formulation or delivery profile, but a regulatory pathway does not eliminate patent risk. The commercial product must still be evaluated against listed patents and non-Orange-Book patent claims.

Key Takeaways

US 10,293,052 is a formulation patent directed to stable, mucoadhesive oral corticosteroid liquids for esophageal treatment.
Claim 1 requires both defined excipient ranges and demonstrated esophageal adhesion.
Claims 2 and 3 specifically cover budesonide and fluticasone propionate.
Claims 4 through 8 add drug-retention and comparative-performance requirements.
Claims 9 through 12 address viscosity, additional maltodextrin, mucoadhesion, and viscosity enhancement.
The patent’s strongest competitive position is against budesonide or fluticasone liquid formulations using CMC and maltodextrin.
Solid dosage forms, inhaled products, and formulations outside the claimed excipient ranges may present lower literal infringement risk.
The definitive expiration date, Orange Book listing, litigation status, and settlement exposure require review of the complete public patent and FDA records.
The most important validity issues are obviousness, indefiniteness of functional terms, and enablement across the broad corticosteroid and excipient genus.

FAQs

Does US 10,293,052 cover all budesonide oral suspensions?

No. The product must also satisfy the liquid vehicle, maltodextrin, CMC, adhesion, stability, and uniformity limitations of claim 1 or the narrower requirements of a dependent claim.

Does using xanthan gum instead of CMC avoid the patent?

Not necessarily. Claim 1 expressly requires CMC, but a product containing xanthan gum may still infringe if it also contains CMC within the claimed range. A product with no CMC would have a stronger noninfringement position under the literal claim language, subject to equivalents analysis.

Can a generic applicant avoid the patent by changing viscosity?

Possibly, but viscosity alone is not the only limitation. The applicant would need to assess maltodextrin and CMC concentrations, esophageal adhesion, stability, uniformity, and any dependent-claim performance requirements.

Does the patent cover swallowed fluticasone from an inhaler?

The patent may cover a swallowed fluticasone product only if the administered composition satisfies the claimed liquid, excipient, stability, and adhesion limitations. The claims do not automatically cover every swallowed inhaled-corticosteroid regimen.

Is US 10,293,052 a method-of-treatment patent?

The supplied claims are composition claims. The therapeutic purpose limits the claimed composition to use for esophageal inflammation or related symptoms, but the patent does not require a separately claimed dosing regimen in claims 1 through 12.

References

United States Patent No. 10,293,052, claims 1-12. United States Patent and Trademark Office.
U.S. Food and Drug Administration. (2024). Eohilia (budesonide) oral suspension prescribing information.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Takeda Pharms Usa	EOHILIA	budesonide	SUSPENSION;ORAL	213976-001	Feb 9, 2024		RX	Yes	Yes	10,293,052	⤷ Start Trial	Y				⤷ 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
Australia	2008321030	⤷ Start Trial
Australia	2008321395	⤷ Start Trial
Australia	2008321396	⤷ Start Trial
Brazil	PI0820081	⤷ Start Trial
Canada	2704943	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 10,293,052

Which drugs does patent 10,293,052 protect, and when does it expire?

Summary for Patent: 10,293,052