US Patent 8,309,127: Claim Scope, Duexis Exclusivity, and Ibuprofen-Famotidine Patent Landscape

US Patent No. 8,309,127 covers immediate-release tablets combining approximately 800 mg ibuprofen with approximately 26 mg famotidine in a physically integrated dosage form. Its core inventive boundary is the controlled limitation of direct ibuprofen-famotidine contact while preserving substantially simultaneous release and long-term chemical stability.

The patent is directed to the formulation used for Duexis, the branded ibuprofen/famotidine product marketed by Horizon Therapeutics and later associated with Ironwood Pharmaceuticals. The strongest claim elements are the narrow active-ingredient ranges, tablet architecture, non-enteric immediate-release profile, limited physical contact between the two active ingredients, and specified stability performance.

What does US Patent 8,309,127 protect?

US 8,309,127 protects a pharmaceutical tablet containing:

Claim element	Limitation
Ibuprofen	750 mg to 850 mg
Famotidine	24 mg to 28 mg
Dosage form	Tablet
Release	Immediate release
Release timing	Both active ingredients begin releasing at approximately the same time
Coating restrictions	No enteric coating or sustained-release formulation
Architecture	Bilayer or tablet-in-tablet formulation
Compatibility	Direct contact is permitted but limited
Stability	Minimum 90% retention under defined storage conditions
Excluded structure	Barrier-coated famotidine multiparticulates dispersed in an ibuprofen matrix

The commercial target is an 800 mg ibuprofen and 26.6 mg famotidine tablet. That strength falls within the literal ranges of independent claims 1 and 14.

The patent does not broadly cover every ibuprofen-famotidine combination. A formulation outside the claimed dosage ranges, using delayed release, sustained release, enteric protection, or a materially different physical architecture may avoid literal infringement, subject to potential doctrine-of-equivalents issues.

How are claims 1 through 13 different from claims 14 through 30?

The patent contains two principal independent claim groups.

Claims 1 through 13: limited direct contact and accelerated-condition stability

Claim 1 requires that direct physical contact between ibuprofen and famotidine is limited. It also requires that at least 90% of each active ingredient remain after one month at 40°C and 75% relative humidity.

Dependent claims 2 through 11 add higher retention thresholds or longer accelerated-storage periods:

Claims	Additional stability requirement
2	At least 95% ibuprofen after one month
3	At least 90% ibuprofen after three months
4	At least 95% ibuprofen after three months
5	At least 90% ibuprofen after six months
6	At least 95% ibuprofen after six months
7	At least 95% famotidine after one month
8	At least 90% famotidine after three months
9	At least 95% famotidine after three months
10	At least 90% famotidine after six months
11	At least 95% famotidine after six months

Claims 12 and 13 specify tablet-in-tablet and bilayer formats.

Claims 14 through 30: quantified contact area and room-temperature stability

Claim 14 replaces the general “limited” contact requirement with a numerical limitation: the direct physical contact surface area between the two active ingredients cannot exceed 130 mm².

It also requires at least 90% retention of both actives after three months at room temperature.

Claims 15 through 28 add room-temperature stability periods and thresholds:

Claims	Stability scope
15, 22	At least 95% ibuprofen or famotidine after three months
16, 23	At least 90% ibuprofen or famotidine after six months
17, 24	At least 95% ibuprofen or famotidine after six months
18, 25	At least 90% ibuprofen or famotidine after nine months
19, 26	At least 90% ibuprofen or famotidine after 12 months
20, 27	At least 90% ibuprofen or famotidine after 24 months
21, 28	At least 90% ibuprofen or famotidine after 36 months

Claims 29 and 30 specify tablet-in-tablet and bilayer forms.

The two claim groups overlap commercially but create different infringement-proof requirements. Claims 1 through 13 require proof that contact is limited, while claims 14 through 30 require measurement or reliable technical evidence showing contact area of 130 mm² or less.

What formulation structures fall within US 8,309,127?

The patent expressly reaches two structures.

Bilayer tablets

In a bilayer tablet, one layer contains ibuprofen and the other contains famotidine. The active layers are physically adjacent, but the formulation must manage chemical interaction and maintain immediate release.

A bilayer product is potentially within claims 13 and 30 if it also satisfies the dosage, release, contact, and stability limitations. The claim language does not require a barrier layer between the active layers. In fact, the claims contemplate direct contact, provided the contact is limited.

Tablet-in-tablet formulations

The claims require that, if the product is a tablet-in-tablet formulation, the first layer completely surrounds the second layer. This limitation is important. A tablet-in-tablet product in which the outer ibuprofen layer does not fully surround the inner famotidine layer may present a noninfringement position under the express claim language.

The patent excludes a formulation in which barrier-coated famotidine multiparticulates are dispersed in an ibuprofen matrix. That exclusion narrows the claim and separates the claimed architecture from a particulate dispersion approach.

Excluded or higher-risk alternatives

The following structures present stronger design-around arguments, although the complete formulation must be evaluated against every claim limitation:

famotidine multiparticulates with a barrier coating dispersed in an ibuprofen matrix;
a dosage form using delayed or enteric release;
a sustained-release product;
a tablet outside the 750-850 mg ibuprofen or 24-28 mg famotidine ranges;
a product in which the active ingredients do not begin releasing at approximately the same time;
a structure with direct contact above 130 mm² for claims 14 through 30;
a non-tablet dosage form, such as a capsule or powder, where the claim’s tablet requirement is not met.

What is the technical problem addressed by the patent?

Ibuprofen and famotidine present formulation-compatibility challenges when placed in direct proximity.

Ibuprofen is a high-dose nonsteroidal anti-inflammatory drug. Famotidine is a low-dose H2-receptor antagonist used to reduce acid-related gastrointestinal effects associated with ibuprofen therapy. A commercial fixed-dose product must combine a large quantity of ibuprofen with a much smaller quantity of famotidine while maintaining:

chemical stability;
acceptable dissolution;
immediate release;
uniform dosage;
manufacturability;
commercial shelf life.

The patent’s solution is a physically integrated tablet that limits active-to-active contact rather than completely separating the ingredients with an impermeable barrier. The specification’s stability tests are central to the inventive concept because stability is not merely an ancillary property. It is expressly incorporated into the claims.

How strong is the patent estate for Duexis?

US 8,309,127 is technically narrow but commercially relevant. Its strength depends on the ability to establish that a competing product meets the formulation and stability limitations.

Strengths

The claimed active-ingredient ranges map closely to the commercial 800 mg/26.6 mg product.
The claims cover both bilayer and tablet-in-tablet configurations.
The claims address immediate release, which matches the commercial product profile.
The stability limitations can distinguish the claimed product from less stable physical mixtures.
Claim 14 provides a numerical contact-area limitation that may be easier to litigate than an unquantified “limited contact” standard.

Weaknesses

The claims are composition claims with numerous cumulative limitations.
A generic manufacturer may be able to avoid literal infringement through a different dosage-form architecture.
“About the same time” may create claim-construction and testing disputes.
“Direct contact ... is limited” is less precise than the 130 mm² limitation.
Stability results depend on test protocol, analytical method, packaging, storage conditions, and batch data.
The patent does not cover ibuprofen or famotidine individually.
The patent does not cover every fixed-dose combination of the two ingredients.

The most defensible infringement theory would likely focus on claims 14 through 30 if the accused product has a measurable direct-contact area at or below 130 mm² and the manufacturer’s stability data establish the required retention.

When does US 8,309,127 lose patent exclusivity?

The patent issued on November 6, 2012, according to the USPTO patent record. Its term is governed by the 20-year term measured from the earliest effective nonprovisional filing date, subject to patent-term adjustment and any applicable patent-term extension. The patent’s effective expiration date must therefore be taken from the USPTO Patent Examination Data System and the FDA Orange Book listing rather than calculated solely from the issue date.[1]

The patent should not be described as expiring 20 years after issuance. That calculation would be incorrect under current US patent-term rules.

For commercial planning, the relevant dates are:

Event	Date or status
Patent issued	November 6, 2012
Product associated with claims	Duexis, ibuprofen/famotidine
FDA approval of Duexis	2011
Regulatory exclusivity	Expired
Patent term	Based on earliest effective nonprovisional filing date, subject to PTA/PTE
Orange Book relevance	Depends on whether the patent remains listed for the approved NDA and whether the listing has been delisted or expired
Generic entry	Controlled by remaining listed patents, certifications, litigation, and any settlement terms

A final expiration date should be verified against the current USPTO record and the latest Orange Book patent listing before a launch decision. The supplied claim text alone does not establish the final adjusted expiration date.

What is the Orange Book status of US 8,309,127?

Duexis was approved under NDA 022519. The relevant Orange Book inquiry is whether US 8,309,127 is listed against NDA 022519 and whether it has an active expiration date.[2]

Orange Book listing has several commercial consequences:

an ANDA applicant must address the listed patent through a Paragraph I, II, III, or IV certification;
a Paragraph IV notice can trigger patent litigation;
timely litigation by the NDA holder or patent owner can create a 30-month stay of ANDA approval under the Hatch-Waxman framework;
expiration or delisting of the patent removes that particular Orange Book barrier, but does not eliminate other listed patents or non-patent exclusivity issues.

FDA’s publication of a patent in the Orange Book does not establish patent validity or infringement. It identifies a listed patent associated with an approved drug product.

What Paragraph IV challenges affect ibuprofen-famotidine products?

A generic applicant seeking approval before expiration of an Orange Book-listed patent may submit a Paragraph IV certification asserting that the patent is invalid, unenforceable, or will not be infringed.

For a product designed around US 8,309,127, the principal Paragraph IV positions would likely target:

Noninfringement

A challenger could argue that its product:

does not use a bilayer or qualifying tablet-in-tablet structure;
does not have direct active-ingredient contact;
has contact exceeding 130 mm²;
uses a barrier-coated multiparticulate system excluded by the claims;
does not provide simultaneous release;
does not meet the claimed stability thresholds;
falls outside the active-ingredient ranges.

Invalidity

Potential invalidity theories would depend on the prior-art record and prosecution history. Relevant categories could include:

anticipation by an earlier ibuprofen-famotidine tablet;
obviousness based on combining known ibuprofen and famotidine formulations;
lack of written description for the quantified contact-area limitation;
lack of enablement across the full claimed ranges;
indefiniteness involving “about the same time” or “limited” contact;
failure to meet statutory requirements for patentable subject matter or claim clarity.

The stability limitations may strengthen patentability if the record shows that the claimed architecture produced unexpected compatibility results. They may also complicate enforcement because the patent owner must prove the accused product meets the specified analytical thresholds.

No conclusion on the outcome of a specific Paragraph IV dispute can be drawn from the claims alone.

Which companies are challenging or competing with Duexis?

The relevant competitive group includes:

Company type	Typical product or strategy
Brand owner	Horizon Therapeutics and successor commercial interests associated with Duexis
Generic ANDA sponsors	Companies developing 800 mg ibuprofen/26.6 mg famotidine fixed-dose tablets
OTC competitors	Manufacturers selling separate ibuprofen and acid-reduction products
Alternative prescription products	Developers using different fixed-dose architectures or separate co-packaged products
Contract manufacturers	Producers capable of bilayer compression, tablet-in-tablet manufacturing, and stability-controlled packaging

The commercial threat is not limited to a literal copy of Duexis. Separate-tablet substitution, co-packaging, therapeutic interchange, and alternative gastrointestinal-risk-management strategies can also reduce branded demand.

A company that markets separate ibuprofen and famotidine tablets may avoid infringement of US 8,309,127 but may not provide the same product substitution profile under the applicable FDA pathway.

What manufacturing and intellectual-property barriers matter?

The patent’s practical barrier is manufacturing integration. A qualifying product must place a high-dose ibuprofen layer and a low-dose famotidine layer into a tablet while controlling:

blend uniformity;
compression force;
layer adhesion;
tablet hardness;
friability;
dissolution;
active-ingredient contact;
moisture exposure;
packaging stability.

A generic applicant must also establish bioequivalence and demonstrate pharmaceutical equivalence under the ANDA framework. The product’s dosage form, strength, release characteristics, and inactive ingredients may affect the regulatory strategy.

Manufacturing evidence can become litigation evidence. Batch records, development reports, blend maps, tablet cross-sections, dissolution data, stability reports, and packaging studies may all bear on whether the formulation satisfies the patent claims.

How does US 8,309,127 compare with broader ibuprofen or famotidine patents?

US 8,309,127 is narrower than a basic compound patent and narrower than a broad method-of-treatment patent.

Patent category	Typical scope	Relevance to US 8,309,127
Ibuprofen compound patent	Ibuprofen as a chemical entity	Generally expired and not the principal barrier
Famotidine compound patent	Famotidine as a chemical entity	Generally expired and not the principal barrier
Method-of-use patent	Treating pain, inflammation, or gastrointestinal symptoms	May raise separate litigation and labeling issues
Formulation patent	Fixed-dose tablet architecture and stability	Core category for US 8,309,127
Manufacturing patent	Compression, layering, coating, or packaging process	Could create additional risk even if composition claims are avoided
Regulatory exclusivity	FDA exclusivity attached to NDA approval	Separate from patent validity and expiration
Biosimilar protection	Biologic reference-product exclusivity	Not applicable because ibuprofen and famotidine are small molecules

Biosimilar risk is therefore not relevant to Duexis. The principal entry pathway is an ANDA for a generic small-molecule product, not a 351(k) biosimilar application.

What litigation and settlement issues should be reviewed?

A complete Duexis freedom-to-operate review should examine:

Orange Book listings for NDA 022519;
USPTO continuity data and patent-term adjustment;
Paragraph IV notices;
district-court complaints and docket activity;
any 30-month-stay orders;
claim-construction rulings;
settlement agreements and launch dates;
authorized-generic arrangements;
additional patents covering formulation, manufacturing, packaging, or methods of use.

A patent settlement can permit an agreed generic launch before the listed patent’s nominal expiration. The settlement date and launch terms may be commercially more important than the patent expiration date.

The claims supplied do not identify a litigation outcome, settlement, authorized generic, or current ANDA approval. Those matters cannot be inferred from the claim language.

What generic launch scenarios exist?

Launch after patent expiration

This is the lowest litigation-risk scenario if no other listed patent remains active and the ANDA is otherwise approvable.

Paragraph IV launch

A generic applicant may launch after a favorable judgment, a dismissal that removes the stay, expiration of the 30-month stay, or a settlement permitting entry.

At-risk launch

A company may launch before final resolution of patent litigation. That strategy exposes the applicant to damages, injunctive relief, and potential liability if the patent is found valid and infringed.

Design-around launch

A manufacturer may pursue a product that avoids one or more claim limitations, such as the tablet architecture, contact-area restriction, release profile, or stability requirement. The regulatory product must still satisfy FDA requirements even if it avoids patent infringement.

Geographic coverage and international relevance

US 8,309,127 has territorial effect only in the United States. Foreign counterparts require separate review in each jurisdiction.

The commercial patent landscape may differ in:

Canada;
Europe;
Japan;
Australia;
emerging markets;
countries where patent term, regulatory linkage, or generic litigation rules differ.

A US noninfringement position does not establish freedom to operate internationally. The relevant foreign patent family members, national-phase status, prosecution outcomes, and expiration dates must be assessed separately.

Key Takeaways

US 8,309,127 is a formulation patent for an immediate-release ibuprofen/famotidine tablet.
The commercial target is approximately 800 mg ibuprofen and 26.6 mg famotidine.
Claims 1 through 13 focus on limited direct contact and accelerated stability.
Claims 14 through 30 add a quantified direct-contact limit of 130 mm² and room-temperature stability requirements.
Bilayer and tablet-in-tablet products are expressly covered when all limitations are satisfied.
Barrier-coated famotidine multiparticulates dispersed in an ibuprofen matrix are expressly excluded.
The patent is not a broad patent on ibuprofen, famotidine, or their therapeutic use.
Duexis faces small-molecule generic risk, not biosimilar risk.
The final launch date depends on the current Orange Book listing, patent-term adjustment, Paragraph IV activity, litigation, and settlements.
The claim text alone does not establish the patent’s final adjusted expiration date or the outcome of any specific generic challenge.

FAQs

Does US 8,309,127 cover all 800 mg ibuprofen and 26 mg famotidine tablets?

No. The product must also meet the tablet, immediate-release, release-timing, contact, architecture, exclusion, and stability limitations.

Can a capsule infringe US 8,309,127?

The asserted claims require a tablet. A capsule would have a strong noninfringement position against these claims, although separate patents could apply.

Is a separate ibuprofen tablet plus a separate famotidine tablet covered?

Generally not by the supplied claims because they require a single pharmaceutical composition in tablet form with first and second layers. Separate-product marketing may raise different regulatory and patent issues.

Why is the 130 mm² contact limitation important?

It converts the qualitative “limited” contact concept into a numerical claim requirement. That can improve precision but creates factual disputes over measurement methodology and the accused product’s physical structure.

Does FDA approval prove that a product does not infringe US 8,309,127?

No. FDA approval addresses regulatory requirements. Patent infringement is determined under patent law, based on the approved product’s composition, structure, manufacturing information where relevant, and claim limitations.

References

United States Patent and Trademark Office. (2012). US Patent No. 8,309,127, pharmaceutical compositions comprising ibuprofen and famotidine. https://patents.google.com/patent/US8309127
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. https://www.fda.gov/drugs/drug-approvals-and-databases/approved-drug-products-therapeutic-equivalence-evaluations-orange-book
U.S. Food and Drug Administration. (2011). Duexis: NDA 022519 approval information. https://www.accessdata.fda.gov/scripts/cder/daf/
United States Code, 35 U.S.C. §§ 154, 271, and 282. (2024). Patent term, infringement, and presumptions of validity. https://uscode.house.gov/.viewer.htm
U.S. Food and Drug Administration. (2024). Abbreviated new drug application approvals and patent certifications. https://www.fda.gov/drugs/abbreviated-new-drug-application-anda/anda-submissions-content-and-format/referencer-listed-drug-rld-and-reference-standard-rs-drugs-lists

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Horizon	DUEXIS	famotidine; ibuprofen	TABLET;ORAL	022519-001	Apr 23, 2011		DISCN	Yes	No	8,309,127	⤷ 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
Austria	E539747	⤷ Start Trial
Australia	2006269894	⤷ Start Trial
Australia	2007275360	⤷ Start Trial
Brazil	PI0714937	⤷ Start Trial
Canada	2615496	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Summary for Patent: 8,309,127