United States Patent 7,189,761: Claim Scope, Expiration, and Nitric Oxide Analgesic Patent Landscape

U.S. Patent No. 7,189,761 protects methods of relieving pain associated with anal fissures, anal ulcers, and hemorrhoidal disease by applying an organic nitric oxide donor to or near the affected area. Its commercial significance is concentrated in topical nitroglycerin products, particularly 0.4% nitroglycerin ointment for chronic anal fissure. The patent does not claim a specific molecule, finished product, or manufacturing process. Its principal protection is a treatment-method framework covering nitric oxide-releasing organic compounds, topical dosage forms, suppositories, carrier systems, and combinations with corticosteroids or local anesthetics.

The patent is no longer a meaningful barrier to ordinary U.S. generic entry if its statutory term has expired, as expected for a patent issued in 2007 with an earliest effective filing date more than 20 years ago. The exact terminal date depends on the patent’s earliest effective nonprovisional filing date and any patent-term adjustment shown in the USPTO record.

What does U.S. Patent 7,189,761 claim?

The independent claims cover two related method categories:

Claim	Principal subject matter	Commercial relevance
1	Treating pain associated with anal fissure, anal ulcer, or hemorrhoidal disease using an effective amount of an organic nitric oxide donor	Broadest disease-and-treatment claim
23	Treating pain associated with an anal fissure, anal ulcer, or hemorrhoid using a composition containing an organic nitric oxide-releasing compound and a physiologically acceptable carrier	Composition-based method claim

The claims require a human patient and pain amelioration. They do not require healing of the fissure, reduction of hemorrhoidal inflammation, relaxation of the internal anal sphincter, or complete disease resolution.

Claim 1: broad method-of-treatment protection

Claim 1 requires:

A human patient.
Pain associated with an anal fissure, anal ulcer, or hemorrhoidal disease.
Administration of an effective amount of an organic nitric oxide donor.
Administration to, or proximate to, the affected area.
Amelioration of pain.

The phrase "organic nitric oxide donor" is materially broader than "nitroglycerin." It can encompass organic compounds that release nitric oxide or a nitric oxide-related species under the claimed treatment conditions. The claim is therefore not limited by chemical name, molecular structure, concentration, excipient, or dosage form.

The main claim-construction issues are the scope of:

"organic nitric oxide donor";
"effective amount";
"proximate to";
"anal disease treatment conditions"; and
"pain is ameliorated."

A product may present infringement risk even if it does not use the term "nitroglycerin" in its labeling, if the active compound is an organic nitric oxide donor and the product is directed to pain from one of the claimed anal disorders.

What dependent claims add to the patent’s protection?

Claims 2 through 22 narrow claim 1 by disease, formulation, route, concentration, carrier, or adjunct active ingredient.

Disease limitations

Claim 2 covers anal fissure or anal ulcer.
Claim 3 covers hemorrhoidal disease.
Claim 6 specifies application to a hemorrhoid.
Claim 7 specifies application to an anal fissure or anal ulcer.

The inclusion of hemorrhoidal disease expands the patent beyond the chronic anal fissure indication associated with commercial nitroglycerin ointment. A product labeled only for hemorrhoidal pain could still fall within the literal scope of claims 1, 3, or 6 if the other elements are met.

Release-condition limitations

Claim 4 requires release of nitric oxide under physiological conditions.
Claim 11 requires release under anal disease treatment conditions.

These limitations impose a functional requirement rather than a particular chemical identity. The patent can therefore reach different organic donor molecules if they release nitric oxide in the relevant biological environment.

Claim 11 may be narrower than claim 4 because it ties the release capability to the conditions existing during treatment of anal disease. The distinction could become important for compounds that release nitric oxide only at a particular pH, temperature, enzyme concentration, or tissue environment.

Dosage-form limitations

The patent covers:

Ointments;
Creams;
Gels;
Lotions;
Liquids;
Semisolids; and
Suppositories.

Claims 5, 8, 9, and 20 through 22 create overlapping formulation positions. The overlap reduces the commercial value of any single dosage-form claim but gives the patent multiple routes to cover a competing product.

A product applied with an applicator, inserted into the anal canal, or placed directly on a fissure could potentially satisfy the "to" or "proximate to" limitations. A product applied to surrounding perianal tissue may also fall within the claim if the affected area is treated indirectly.

Concentration limitations

Claims 10 and 16 cover compositions containing the nitric oxide donor at 0.01% to 10% by weight.

This range includes a 0.4% nitroglycerin ointment. It also covers many lower- and higher-strength formulations. The endpoints are included unless the patent specification or prosecution history establishes a different construction.

The concentration limitation applies to the nitric oxide donor in the composition, not necessarily to the total amount of nitric oxide released. A formulation containing a donor below 0.01% would avoid these concentration-limited claims but could remain exposed to broader claims 1 or 23.

Carrier and combination therapy limitations

Claim 17 identifies the following carriers:

White petrolatum;
Mineral oil;
Lanolin;
Distilled water;
Acetone; and
Cocoa butter.

Claims 18 and 19 cover compositions that also contain:

A corticosteroid; or
A local anesthetic.

Claim 17 is not limited to a single carrier. The wording "a carrier selected from the group consisting of" generally requires at least one listed carrier. A formulation using a different excipient may avoid claim 17 while remaining within claim 16 or claim 23.

Claims 18 and 19 are commercially relevant to combination products intended to address both pain and inflammation. They do not require a particular corticosteroid or local anesthetic.

How broad are the independent claims?

Scope dimension	Claim 1	Claim 23
Active agent	Organic nitric oxide donor	Organic compound capable of releasing nitric oxide
Patient	Human	Human
Disease	Anal fissure, anal ulcer, or hemorrhoidal disease	Anal fissure, anal ulcer, or hemorrhoid
Therapeutic objective	Pain amelioration	Pain amelioration
Administration site	To or proximate to affected area	To or proximate to affected area
Carrier required	No express carrier requirement	Yes, physiologically acceptable carrier
Specific dosage form	No	No
Specific concentration	No	No
Combination active required	No	No

Claim 1 is the principal broad claim because it does not require a carrier or a defined formulation. Claim 23 may be easier to read on a finished topical pharmaceutical product because most commercial products contain a carrier, but it is narrower because of that express requirement.

The patent does not claim:

Nitroglycerin as a compound;
A specific nitroglycerin concentration independently of treatment;
A composition sold without a treatment step;
A manufacturing process;
A package or applicator;
A particular dosing frequency;
A specific duration of treatment;
Sphincter relaxation as an independent endpoint; or
A method for treating anal disease without pain.

What formulations are protected by U.S. Patent 7,189,761?

The strongest formulation overlap exists for a topical organic nitrate product in an ointment or gel containing 0.01% to 10% donor by weight and a physiologically acceptable carrier.

A 0.4% nitroglycerin ointment using petrolatum, mineral oil, or another listed carrier can implicate claims 5, 10, 16, 17, and 20, in addition to the independent claims. The same active ingredient in a suppository could implicate claims 9, 13, 22, and 26.

The claims do not require a particular release-control mechanism. A formulation using a transdermal enhancer, mucoadhesive, controlled-release matrix, or pH-modifying excipient could remain within scope if it satisfies the active-agent, disease, administration, and pain-relief limitations.

What is the relationship to Rectiv and topical nitroglycerin?

Rectiv is a 0.4% nitroglycerin ointment approved by the FDA for the treatment of moderate to severe pain associated with chronic anal fissure. Its active ingredient, nitroglycerin, is an organic nitrate and nitric oxide donor. The product’s use falls within the central commercial field addressed by U.S. Patent 7,189,761.

The relevant comparison is:

Product or product type	Likely relationship to patent claims
0.4% nitroglycerin ointment for chronic anal fissure pain	Directly within the patent’s core technical and commercial field
Nitroglycerin cream or gel for anal fissure	Potentially within claims covering topical dosage forms
Nitroglycerin suppository for anal pain	Potentially within suppository claims
Other organic nitrates for hemorrhoidal pain	Potentially within broader disease and donor claims
Non-nitric-oxide local anesthetic alone	Outside the active-agent requirement
Topical calcium-channel blocker or botulinum toxin	Generally outside the literal organic nitric oxide donor requirement
Oral nitric oxide donor for systemic pain relief	Potentially outside the site-of-application limitation, depending on facts
Nitric oxide-releasing inorganic material	Potentially outside claims requiring an organic donor or organic compound

The patent’s value was highest before approval and commercialization of an approved topical nitroglycerin product. Once the statutory term ended, the claims ceased to provide an enforceable barrier to a U.S. generic that otherwise satisfies FDA requirements.

When does U.S. Patent 7,189,761 lose exclusivity?

Patent exclusivity and FDA regulatory exclusivity are separate.

Patent term

Under 35 U.S.C. §154, a U.S. utility patent generally expires 20 years from the earliest effective U.S. nonprovisional filing date, subject to patent-term adjustment, terminal disclaimers, and any patent-term extension. A patent issued in 2007 does not ordinarily receive a fresh 20-year term from its issue date.

Because U.S. Patent 7,189,761 was issued in 2007 and relates to an older priority chain, its ordinary patent term has ended or is no longer a practical barrier to entry. The controlling date is the USPTO patent-term calculation, not the issue date.

FDA exclusivity

FDA exclusivity is tied to the approved product and application. It does not automatically extend the patent term. Rectiv’s approval created regulatory protections under the applicable NDA framework, but those protections were separate from the patent claims and would not block approval indefinitely after their statutory period.

What is the Orange Book status of the patent?

A patent’s Orange Book status depends on whether the NDA holder submitted it for listing and whether FDA accepted it as claiming the approved drug, formulation, or method of use.

For a topical nitroglycerin product, the relevant Orange Book analysis is:

Whether U.S. Patent 7,189,761 was listed for the NDA.
Whether the listed claims covered the approved chronic anal fissure indication.
Whether the patent remained unexpired on the date of an abbreviated new drug application.
Whether the ANDA applicant submitted a Paragraph IV certification or a certification that the patent had expired.

The patent’s method-of-use character is important. A generic applicant that seeks only a noninfringing indication may use a section viii statement to carve out the patented use, where FDA labeling and the Orange Book listing permit that approach. A full-label generic seeking the chronic anal fissure indication would face a more direct patent-certification issue while the patent remained listed and unexpired.

Were Paragraph IV challenges or patent settlements likely?

The patent’s claims were natural candidates for a Paragraph IV challenge because they cover a commercially important topical nitroglycerin indication and do not claim a narrow chemical structure. The likely invalidity and noninfringement arguments include:

Anticipation by prior topical nitric oxide donor treatment;
Obviousness based on known nitroglycerin use, anal fissure treatment, and topical analgesic formulations;
Lack of written description for the full breadth of "organic nitric oxide donor";
Enablement challenges based on the breadth of compounds and treatment conditions;
Failure to prove pain amelioration for every covered donor and formulation;
Noninfringement based on an alternative active ingredient or nonanal administration route; and
Noninfringement based on a product label that excludes the patented indication.

No reliable conclusion about a particular Paragraph IV notice, district-court action, settlement, or launch date can be drawn from the claim text alone. The relevant evidence would be found in FDA ANDA records, PACER complaints and docket entries, the Orange Book, and USPTO assignment and maintenance records.

How strong is the patent estate?

The patent has broad conceptual coverage but limited structural depth.

Strength	Assessment
Disease coverage	Broad across fissure, ulcer, and hemorrhoidal disease
Active-agent coverage	Broad because no single donor is required
Formulation coverage	Moderate, with overlapping dosage-form and carrier claims
Chemical specificity	Weak; no defined molecular structure or Markush list appears in the supplied claims
Manufacturing protection	None apparent
Device protection	None apparent
Regulatory relevance	High for a topical nitroglycerin product while the patent was listed and unexpired
Post-expiration value	Low as an enforceable exclusion right
Litigation vulnerability	Potentially significant due to breadth and functional language

The estate is stronger against a labeled product that openly uses nitroglycerin for anal fissure pain than against an off-label or label-carved product using a different nitric oxide donor. It is also stronger against topical and suppository products than against systemic products.

What generic launch risks exist?

Before patent expiration

A generic applicant faced four main risks:

Paragraph IV litigation. The NDA holder could sue within the statutory period after receiving notice.
Label overlap. A generic label reproducing the chronic anal fissure indication could create direct method-of-use exposure.
Formulation overlap. A 0.4% topical nitroglycerin product could satisfy several dependent claims.
Induced infringement allegations. Marketing materials, labeling, or physician instructions could be used to show encouragement of the patented method.

After patent expiration

After expiration, the principal risks shift from patent infringement to:

FDA formulation equivalence;
Bioequivalence or comparative clinical requirements;
Product-specific exclusivity;
Trademark and trade-dress issues;
State substitution rules;
Manufacturing scale-up; and
Commercial access to prescribers and pharmacies.

The patent would not create a post-expiration exclusivity period. A generic manufacturer could pursue the same active ingredient and indication, subject to FDA approval and any separate unexpired patents or regulatory exclusivities.

How does this patent compare with alternative anal-fissure therapies?

Therapy	Mechanism	Relationship to Patent 7,189,761
Topical nitroglycerin	Nitric oxide donation and internal sphincter relaxation	Core field of the patent
Topical diltiazem	Calcium-channel blockade	Generally outside literal donor claims
Topical nifedipine	Calcium-channel blockade	Generally outside literal donor claims
Botulinum toxin injection	Neuromuscular blockade	Outside topical donor claims
Local anesthetic	Sensory analgesia	Outside claims unless combined with a donor
Corticosteroid	Anti-inflammatory effect	Outside claims unless combined with a donor
Surgery	Sphincterotomy or other operative treatment	Outside the claimed pharmaceutical method

The patent therefore did not control the entire anal-fissure market. Its practical reach was concentrated in nitric oxide donor products, particularly topical and rectal formulations.

Key Takeaways

U.S. Patent 7,189,761 is a method-of-treatment patent, not a nitroglycerin composition or manufacturing patent.
Its central claims cover organic nitric oxide donors used to relieve pain from anal fissures, anal ulcers, and hemorrhoidal disease.
The claims reach topical ointments, creams, gels, lotions, liquids, semisolids, and suppositories.
Claims 10 and 16 cover donor concentrations from 0.01% to 10% by weight.
The claims expressly cover formulations containing corticosteroids, local anesthetics, and listed carriers such as white petrolatum and mineral oil.
A 0.4% nitroglycerin ointment for chronic anal fissure pain falls within the patent’s core commercial field.
The patent does not protect competing non-nitric-oxide treatments such as diltiazem, nifedipine, botulinum toxin, or local anesthetic alone.
The patent’s statutory term is no longer expected to provide an active U.S. exclusivity barrier, subject to the USPTO’s official term calculation.
Current generic-entry risk depends more on FDA approval, Orange Book status, and any separate unexpired patents than on the supplied claims.

FAQs About U.S. Patent 7,189,761

Does U.S. Patent 7,189,761 cover nitroglycerin itself?

No. The supplied claims cover methods using an organic nitric oxide donor. They do not claim nitroglycerin as a standalone chemical composition.

Does the patent cover hemorrhoid treatment?

Yes. Claims 1, 3, 6, 23, and 24 expressly address hemorrhoidal disease or a hemorrhoid.

Does the patent cover a suppository?

Yes. Claims 9, 13, 22, and 26 expressly cover suppository formulations or administration.

Can a generic avoid the patent by using a concentration below 0.01%?

That could avoid claims 10 and 16, but it would not automatically avoid claims 1 or 23. The active compound, disease, administration site, carrier, and pain-relief limitations would still require separate analysis.

Is there biosimilar risk associated with this patent?

No. The patent concerns small-molecule nitric oxide donor treatments, not a biologic. The relevant competitive threat is generic or 505(b)(2) entry, not biosimilar substitution.

References

United States Patent and Trademark Office. (2007). U.S. Patent No. 7,189,761: Treatment of anal disorders with nitric oxide donors.
U.S. Food and Drug Administration. (2011). Rectiv (nitroglycerin) ointment, 0.4% prescribing information.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations.
United States Code. (2024). 35 U.S.C. § 154: Contents and term of patent; provisional rights.
United States Code. (2024). 21 U.S.C. § 355: New drugs.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	196082	⤷ Start Trial
Austria	374607	⤷ Start Trial
Australia	2282395	⤷ Start Trial
Canada	2168247	⤷ Start Trial
China	1107499	⤷ Start Trial
China	1131392	⤷ Start Trial
Germany	69518729	⤷ Start Trial
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Details for Patent: 7,189,761

Summary for Patent: 7,189,761