United States Patent 7,951,131: Scope, Claim Construction, Expiration, and Sinus-Implant Patent Landscape

U.S. Patent No. 7,951,131 covers methods for placing drug-releasing implants into a paranasal sinus through a delivery device. Its commercial relevance is concentrated in implant-assisted treatment of sinusitis and localized anti-inflammatory therapy, particularly biodegradable steroid implants delivered through conduits, catheters, or similar devices.

The patent is method-focused. It does not claim a drug implant in isolation. Infringement generally requires performance of the claimed delivery sequence: loading the device, creating access to the sinus with the loaded device, advancing at least part of the device into the sinus, and releasing the implant into the sinus.

What does U.S. Patent 7,951,131 claim?

The independent claims establish two related method categories:

Claim	Core subject matter	Therapeutic requirement
1	Delivering one or more drug-releasing implants into a paranasal sinus cavity	Active agent for treatment of sinusitis
31	Delivering one or more drug-releasing implants into a paranasal sinus cavity	Active agent for reducing inflammation

Claims 2-30 depend from claim 1. Claim 32 depends from claim 31. The claim set therefore has one primary procedural architecture with narrower limitations covering implant structure, delivery mechanics, device geometry, drug identity, polymer composition, and release duration.

Claim 1: broadest practical scope

Claim 1 requires all of the following:

A delivery device is loaded with one or more drug-releasing implants.
Access to a paranasal sinus cavity is created using the loaded device.
At least part of the device is advanced into the sinus cavity.
The implant or implants are delivered from the device into the sinus cavity.
The implant contains a therapeutic amount of an active agent for treating sinusitis.

The claim does not expressly require:

A particular sinus, such as the maxillary, frontal, ethmoid, or sphenoid sinus.
A particular steroid.
A biodegradable implant.
A particular delivery pressure.
A pusher.
A specific catheter diameter.
A surgical procedure performed after or before sinus surgery.
A fixed treatment duration.
A specific implant shape.

The absence of these limitations makes claim 1 the principal risk-bearing claim for devices that place drug-eluting implants directly into sinus cavities.

The claim is narrower than a claim directed simply to “a drug-releasing sinus implant.” A party that manufactures an implant but does not perform, direct, or induce the claimed delivery method would not necessarily practice claim 1. The delivery sequence is central.

Claim 31: inflammation-focused alternative

Claim 31 repeats the delivery steps but changes the therapeutic limitation. The implant must contain an active agent for reduction of inflammation rather than expressly for treatment of sinusitis.

This language may reach products positioned for postoperative inflammation, mucosal edema, or other inflammatory conditions involving the sinus. It may also create a broader infringement theory where a product’s labeling emphasizes inflammation reduction rather than sinusitis treatment.

The practical scope depends on claim construction of “active agent for the reduction of inflammation.” Corticosteroids are the most obvious candidates, but the claim language is not limited to corticosteroids.

What implant structures are protected by U.S. Patent 7,951,131?

The dependent claims cover a wide range of implant architectures. They are relevant to both product design and freedom-to-operate analysis.

Shape-changing and retention implants

Claim 2 covers a solid implant having:

A first delivery form that facilitates passage into the sinus; and
A second form that is different and substantially prevents clearance from the sinus.

This limitation targets deployable implants that change shape after exiting the delivery conduit. Examples could include an implant compressed for insertion and expanded, unfolded, curved, or otherwise reconfigured after deployment.

The claim does not specify the exact mechanism for the shape change. A design that remains in the same physical form after delivery would be less likely to fall within claim 2, although it could still implicate claim 1 or other dependent claims.

Implant dimensions and delivery mechanics

Claim 3 recites an implant diameter of approximately 5 millimeters while in the conduit. The “about” qualifier creates a range-construction issue. Exact infringement cannot be determined from nominal diameter alone because the relevant measurement is the implant’s size while inside the conduit.

Claim 4 covers delivery with a pusher. Claim 5 covers delivery with pressurized gas. These claims reach different actuation systems:

Delivery mechanism	Relevant claim
Mechanical pusher	Claim 4
Pressurized gas	Claim 5
Other release mechanism	Potentially claim 1, if all base limitations are met

A system using suction, fluid pressure, a stylet, a plunger, or an automated actuator could avoid claims 4 and 5 while remaining exposed to claim 1.

Conduit geometry

Claims 7-11 cover a delivery device with a conduit and specify the location of the distal opening:

Claim 7: delivery device comprises a conduit.
Claim 8: distal portion is angulated.
Claim 9: angulation from approximately 0 to 135 degrees.
Claim 10: distal opening at the conduit tip.
Claim 11: distal opening in the conduit side wall.

These claims are particularly relevant to steerable or curved sinus-access systems. Claims 8 and 9 may apply to devices designed to navigate anatomically difficult sinus pathways. Claims 10 and 11 divide terminal discharge architectures between end-opening and side-opening conduits.

Fracturable implants and particulate formats

Claim 12 covers implants with predetermined fracture lines. Claims 29 covers implants in the form of a:

Rod
Pellet
Bead
Strip
Microparticle

A product may avoid one specific format while remaining within another dependent claim or within the broader independent claim if it is a drug-releasing implant.

What drugs and polymers are covered?

Claims 13-23 identify active agents and matrix materials.

Corticosteroid limitations

Claims 14-17 specifically recite:

Claim	Active agent
14	Mometasone furoate
15	Budesonide
16	Fluticasone propionate
17	Triamcinolone acetonide

These claims are narrower than claim 1. A product containing mometasone furoate, for example, must still satisfy every limitation of claim 1, including the claimed delivery method and sinus placement.

The patent does not limit claim 1 to the four named corticosteroids. Other anti-inflammatory agents may fall within claims 1, 13, or 31 if the therapeutic and delivery limitations are met.

Biodegradable and mucoadhesive matrices

Claims 6 and 18-23 cover implant material choices:

Claim 6: biodegradable polymeric implant.
Claim 18: biodegradable matrix.
Claim 19: biodegradable polymer matrix.
Claim 20: mucoadhesive polymer.
Claim 21: PLGA copolymer.
Claims 22-23: lactic acid or glycolic acid.

PLGA is commercially important because it is widely used for controlled-release biodegradable systems. Claims 21-23 are compositionally narrower than the independent claims but may create additional barriers for products using PLGA, lactic acid, or glycolic acid as structural or release-controlling components.

The claim set does not require every implant to use PLGA. A non-PLGA implant may still be captured by claim 1, claim 13, or claim 31 if the delivery process and therapeutic limitations are met.

What release periods and drug loading levels are protected?

Claims 24-27 address release duration:

Claims	Release period
24	Approximately one week to three months
25	Approximately two to four weeks
26	At least approximately one week
27	At least approximately two weeks

Claims 24 and 25 are bounded ranges. Claims 26 and 27 are open-ended minimum-duration limitations. A product releasing drug for four weeks could potentially fall within several of these claims if the other requirements are satisfied.

Claim 28 covers active-agent loading from approximately 5% to approximately 90% by weight. This range is broad and could reach many drug-polymer formulations. Analytical testing would be needed to determine whether the relevant weight percentage is calculated against the entire implant, excluding coatings, or using another formulation convention.

How strong is the patent estate for U.S. Patent 7,951,131?

The strongest protection is concentrated in claim 1 and claim 31 because they do not require a specific steroid, polymer, implant shape, or device configuration.

Strength factors

The claim set has several commercially relevant strengths:

It covers the complete delivery workflow rather than only the implant composition.
It applies to any paranasal sinus cavity.
It is not limited to one named corticosteroid.
It covers both sinusitis treatment and inflammation reduction.
The independent claims do not require biodegradability.
The claims reach multiple delivery architectures, including conduits, pushers, and pressurized gas.
Dependent claims cover important product-development choices such as PLGA, mucoadhesion, shape change, fracture lines, and extended release.

Vulnerability factors

The principal limitations and potential attack points are procedural:

The delivery device must be loaded before access is created.
Access must be created with the loaded delivery device.
At least part of the device must advance into the sinus.
The implant must be delivered from the device into the sinus.
The active agent must be present in a therapeutic amount.
The implant must qualify as a “drug-releasing implant.”

A competing system may seek to separate the access step from the loading step, use a pre-positioned delivery system, deliver the implant through a device that is not advanced into the sinus, or place the implant outside the sinus cavity. Those approaches would require careful analysis under claim construction and induced-infringement principles.

Potential validity issues would likely focus on prior art combinations involving:

Sinus-access catheters.
Drug-eluting stents.
Biodegradable controlled-release implants.
Local corticosteroid delivery.
Expandable or shape-changing implants.
Endoscopic sinus surgery.
Delivery of implants through conduits.

The breadth of claim 1 increases potential prior-art exposure. The narrower polymer, drug, geometry, and release-period claims may be more defensible if the specification supports those combinations and the prior art does not disclose the complete claimed method.

When does U.S. Patent 7,951,131 lose exclusivity?

A U.S. utility patent generally expires 20 years from the earliest effective nonprovisional filing date, subject to patent-term adjustment, patent-term extension, terminal disclaimers, and other statutory adjustments under 35 U.S.C. §§ 154 and 156.

The patent issued on May 31, 2011. Its actual expiration cannot be established from the claim text alone because the operative term depends on the patent’s priority chain, filing history, patent-term adjustment, and any extension or disclaimer recorded by the USPTO.

The patent’s enforceability also depends on maintenance-fee status. Failure to pay a maintenance fee can result in lapse, although a patent may be revived in certain circumstances. The USPTO Patent Center and Patent Examination Data System are the controlling sources for the current term and maintenance history (United States Patent and Trademark Office, n.d.-a, n.d.-b).

What is the Orange Book status of U.S. Patent 7,951,131?

U.S. Patent 7,951,131 is directed to methods of delivering a drug-releasing implant and is not, based on the claim text, a conventional patent claim to an approved drug substance or finished drug product.

Orange Book listing is product-specific. The FDA lists patents submitted by an NDA holder that claim the approved drug substance, drug product, or an approved method of use under the applicable statutory and regulatory framework (FDA, 2023).

For sinus implants, the regulatory product may be regulated as a combination product or device-led product rather than as a conventional NDA drug. A patent’s absence from the Orange Book would not establish freedom to operate. It would mean only that the patent is not being used as an Orange Book-listed patent for a particular approved product.

Which commercial products are most relevant?

PROPEL sinus implants

The most direct commercial relevance is to bioabsorbable corticosteroid-eluting sinus implants such as PROPEL products associated with Acclarent and Johnson & Johnson. PROPEL products use mometasone furoate and are designed for localized delivery in the sinus following sinus surgery. FDA-cleared indications and product configurations have evolved over time, including products intended for different sinus locations (FDA, 2011).

A PROPEL-type product may implicate the patent’s steroid, biodegradable matrix, controlled-release, implant-format, and sinus-delivery concepts. Infringement analysis would still require mapping the actual procedure and device operation to the limitations of claims 1, 2, 6, 14, 18-21, and 24-29.

SINUVA sinus implant

SINUVA, associated with Intersect ENT and later Medtronic, is a corticosteroid-releasing sinus implant containing mometasone furoate. FDA approval was based on placement in the ethmoid sinus of adults with recurrent nasal polyps after prior ethmoid sinus surgery (FDA, 2017).

SINUVA is commercially relevant because it illustrates a different market position from postoperative PROPEL products. A product directed to recurrent nasal polyps may raise method-of-use questions under the patent’s sinusitis and inflammation language, but the answer depends on labeling, actual delivery technique, and the interpretation of “paranasal sinus cavity.”

Competitive landscape

Product category	Typical active agent	Delivery context	Relevance to Patent 7,951,131
Postoperative bioabsorbable sinus implant	Mometasone furoate	Placement after sinus surgery	High
Sinus implant for recurrent polyps	Mometasone furoate	Ethmoid sinus placement	High
Locally delivered budesonide system	Budesonide	Sinus or nasal cavity delivery	Potentially high
Nonsteroidal biodegradable implant	Other anti-inflammatory agent	Direct sinus placement	Depends on therapeutic and delivery facts
Nasal spray or irrigation	Various	No implant placed in sinus	Generally outside the principal claim architecture
Conventional sinus stent without drug release	None or nontherapeutic coating	Sinus support	Generally outside the drug-releasing implant requirement

What patent litigation and Paragraph IV risks exist?

The patent’s claims are method claims, so a conventional Abbreviated New Drug Application Paragraph IV challenge would be less straightforward than for a tablet, injectable, or conventional nasal spray. ANDA litigation requires an approved drug product and a patent listed for that product. A device-led sinus implant may instead involve a premarket approval, 510(k), or combination-product pathway, depending on the product’s classification.

A competing sponsor could face several forms of patent exposure:

Direct infringement if it performs the delivery method.
Induced infringement if its labeling instructs physicians to perform the claimed steps.
Contributory infringement if it supplies a specially adapted delivery system or implant.
Patent litigation based on related continuation or divisional patents, even if 7,951,131 itself expires or is invalidated.
Regulatory and commercial risk from patents outside the Orange Book.

The most important diligence issue is family-level review. A patent landscape limited to U.S. Patent 7,951,131 may miss continuation patents covering the implant composition, deployment mechanism, sinus location, or method of treatment. Patent-family prosecution history, terminal disclaimers, continuations, reexaminations, and post-grant proceedings should be reviewed in the USPTO record before relying on a freedom-to-operate conclusion.

What geographic coverage does the patent provide?

U.S. Patent 7,951,131 provides territorial protection only in the United States. It may affect:

Manufacturing in the United States.
Importation of covered implants or delivery systems.
U.S. commercialization.
U.S. clinical-use instructions.
U.S.-directed labeling and training.

Foreign protection requires separate national or regional patents. A global launch analysis must review corresponding family members in Europe, Canada, Japan, China, Australia, and other target markets. Foreign claims may differ materially because of prosecution amendments, added subject-matter rules, unity objections, and national claim-construction standards.

What manufacturing and IP barriers matter most?

The highest manufacturing-related risks concern the combination of:

A biodegradable or PLGA matrix.
A corticosteroid, particularly mometasone furoate.
Controlled release over at least one to four weeks.
A solid rod, pellet, bead, strip, or microparticle.
Delivery through a conduit into the sinus.
A pusher or gas-assisted deployment system.
A shape-changing or retention-oriented design.

A manufacturer can reduce risk by separating the implant and delivery-device businesses, using a non-implant local-delivery format, avoiding direct sinus placement, or designing a procedure that does not practice the claimed sequence. Those strategies may create new regulatory or clinical limitations and do not automatically avoid related patent families.

Key Takeaways

U.S. Patent 7,951,131 primarily protects the method of delivering a drug-releasing implant into a paranasal sinus.
Claims 1 and 31 are the broadest and most commercially significant claims.
The patent covers both sinusitis treatment and reduction of inflammation.
Dependent claims address shape-changing implants, 5-millimeter conduit dimensions, pushers, pressurized gas, conduit geometry, fracture lines, corticosteroids, PLGA, mucoadhesive polymers, and extended release.
Mometasone furoate products such as PROPEL and SINUVA are commercially relevant to the claim scope.
The patent is not limited to mometasone or to biodegradable implants at the independent-claim level.
Orange Book status cannot be used as the sole measure of risk for sinus-implant products.
The actual expiration date requires review of the patent’s priority chain, patent-term adjustment, maintenance status, and any terminal disclaimer.
Continuation and foreign-family patents may create material residual risk after this patent expires.
The principal design-around opportunities concern delivery sequence, device advancement, implant placement location, and whether the product qualifies as a drug-releasing implant.

FAQs About U.S. Patent 7,951,131

Does Patent 7,951,131 cover a mometasone furoate sinus implant by itself?

No. The independent claims require a method of loading, advancing, and delivering the drug-releasing implant into a paranasal sinus cavity. The implant composition alone is not the complete claimed invention.

Does the patent cover budesonide implants?

Potentially. Claim 15 expressly recites budesonide, but the product must also satisfy the delivery, sinus-placement, implant, and therapeutic-purpose limitations inherited from claim 1.

Can a nasal spray infringe Patent 7,951,131?

A conventional nasal spray generally would not satisfy the requirement to deliver one or more drug-releasing implants into a paranasal sinus cavity. The result could differ for a spray that deposits an implantable particulate or microparticle system into the sinus.

Does the patent cover delivery into the nasal passage rather than the sinus?

The claims require delivery into a paranasal sinus cavity. Delivery confined to the nasal passage would generally present a different claim issue unless the product or procedure also places the implant in the sinus cavity.

Is a patent invalid if it is not listed in the Orange Book?

No. Orange Book listing and patent validity are separate issues. A patent may be enforceable without being listed in the Orange Book, particularly where the product is regulated as a device-led or combination product.

References

Food and Drug Administration. (2011). PROPEL sinus implant: FDA 510(k) and product information. U.S. Department of Health and Human Services.

Food and Drug Administration. (2017). SINUVA sinus implant: FDA PMA P160047. U.S. Department of Health and Human Services.

Food and Drug Administration. (2023). Approved drug products with therapeutic equivalence evaluations. U.S. Department of Health and Human Services.

United States Patent and Trademark Office. (n.d.-a). U.S. Patent No. 7,951,131, Patent Center record. U.S. Department of Commerce.

United States Patent and Trademark Office. (n.d.-b). Patent term adjustment and maintenance fee records. U.S. Department of Commerce.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Australia	2004222340	⤷ Start Trial
Canada	2518960	⤷ Start Trial
European Patent Office	1605863	⤷ Start Trial
European Patent Office	3103422	⤷ Start Trial
Japan	2006520786	⤷ Start Trial
World Intellectual Property Organization (WIPO)	2004082525	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 7,951,131

Summary for Patent: 7,951,131