United States Patent 8,092,832: Fentanyl Buccal Tablet Claims, Scope and Patent Landscape

U.S. Patent No. 8,092,832 protects a narrowly defined fentanyl buccal tablet formulation. Independent claim 1 requires a specific fentanyl dose range, an effervescent acid-bicarbonate system, a separate carbonate pH adjuster, starch glycolate, mannitol, buccal delivery, and a dwell time below 30 minutes. The claim is materially narrower than a general claim to fentanyl buccal delivery or effervescent fentanyl tablets.

The principal enforcement risk is against a product that reproduces the full excipient architecture, rather than against every fentanyl buccal tablet. The most important design-around variables are the carbonate pH adjuster, starch glycolate, mannitol grade or concentration, effervescent composition, dose, and packaging.

What patent is U.S. 8,092,832?

U.S. Patent No. 8,092,832 is directed to fentanyl compositions and methods of use, including rapidly dissolving or disintegrating oral dosage forms designed to deliver fentanyl through the oral mucosa. The patent issued on Jan. 10, 2012, from a continuation-stage U.S. application in a broader family covering fentanyl oral transmucosal formulations.[1]

The claims supplied for analysis focus on a tablet rather than on a broad therapeutic method. Claim 1 combines formulation composition and performance limitations:

Claim element	Required limitation
Active ingredient	Fentanyl free base or equivalent salt amount
Dose	About 100, 200, 300, 400, 600, or 800 micrograms, calculated as free base
Effervescent system	Food acid plus bicarbonate
Effervescent quantity	About 15% to about 60% by tablet weight
Separate pH adjuster	Carbonate, about 0.5% to about 25% by tablet weight
Disintegrant	Starch glycolate, about 0.25% to about 20%
Diluent or matrix component	Mannitol, about 10% to about 80%
Administration	Buccal delivery across the oral mucosa
Residence time	Less than about 30 minutes
Dependent packaging limitation	F1 package

The claim is an all-elements claim. A competing product generally must satisfy every limitation of claim 1, either literally or under the doctrine of equivalents, before infringement becomes a substantial issue.

What does claim 1 of U.S. 8,092,832 cover?

Claim 1 covers a defined combination of fentanyl, excipients, dose levels, and buccal performance. It does not cover every fentanyl tablet, every fentanyl citrate product, or every effervescent oral transmucosal formulation.

Fentanyl dose limitation

The claim identifies six dose levels:

100 micrograms
200 micrograms
300 micrograms
400 micrograms
600 micrograms
800 micrograms

The dose is measured as fentanyl free base. A salt, such as fentanyl citrate, is covered only in an amount equivalent to the specified free-base quantity.

The use of “about” creates a numerical boundary issue. Courts typically interpret “about” in light of the specification, examples, prosecution history, and technical precision of the field. It does not automatically mean that every dose near the listed value falls within the claim. A product at 500 micrograms, for example, would face a substantial literal-scope question because 500 micrograms is not one of the expressly listed dose points.

Effervescent agent

The effervescent agent must include both:

A food acid; and
A bicarbonate.

The combined effervescent agent must represent approximately 15% to 60% of the tablet by weight. A formulation using only bicarbonate, only an acid, or a non-food acid system would create a potential literal noninfringement position, subject to the specification and equivalents analysis.

The claim does not require a particular food acid. Citric acid, malic acid, tartaric acid, fumaric acid, and related pharmaceutically acceptable food acids could potentially fall within the claim if the formulation and intrinsic patent disclosure support that interpretation.

Separate carbonate pH adjuster

The tablet must contain a carbonate pH-adjusting substance at approximately 0.5% to 25% by weight. The carbonate must be different from the food acid and bicarbonate used in the effervescent agent.

This separation is legally important. The claim does not merely require a carbonate somewhere in the formulation. It requires:

A food acid-bicarbonate effervescent system; and
A distinct carbonate pH adjuster.

A formulation in which the same ingredient is argued to perform both functions could create a claim-construction and infringement dispute. A formulation using a non-carbonate buffer, such as a phosphate or citrate buffer, presents a clearer literal design-around position.

Starch glycolate

Claim 1 requires starch glycolate at approximately 0.25% to 20% by tablet weight. Claims 2 and 3 narrow this limitation:

Claim	Starch glycolate range
Claim 1	About 0.25% to about 20%
Claim 2	About 0.5% to about 15%
Claim 3	About 0.5% to about 10%

Claim 3 is narrower but may be commercially important because practical immediate-release formulations often use disintegrant concentrations within this range.

The claim requires starch glycolate, not merely any superdisintegrant. Crospovidone, croscarmellose sodium, low-substituted hydroxypropyl cellulose, or sodium starch glycolate alternatives may avoid literal infringement if the product does not also contain starch glycolate within the claimed range.

Mannitol

Mannitol must be present at approximately 10% to 80% by weight. Claim 5 specifies spray-dried mannitol.

The broad claim reaches mannitol generally. Claim 5 is narrower and depends on the physical form or manufacturing grade being spray dried. A product containing crystalline mannitol, granular mannitol, or another grade may avoid claim 5 while remaining potentially exposed to claim 1.

Buccal delivery and dwell time

The tablet must be suitable for delivery across the oral mucosa by buccal administration and must have a dwell time below approximately 30 minutes.

These are functional limitations. They may be assessed through:

Product labeling;
Clinical or pharmacokinetic protocols;
In vitro dissolution or disintegration testing;
Human-use data;
Manufacturing specifications; and
The formulation’s intended placement in the buccal cavity.

A tablet that is swallowed as the principal route of administration would have a stronger noninfringement position. A product expressly instructed to sit between the cheek and gum for 10 to 20 minutes presents greater risk.

What do claims 2 through 7 add?

Claims 2 through 7 create narrower fallback positions.

Claim	Added limitation	Commercial significance
2	Starch glycolate at about 0.5% to 15%	Captures a narrower practical formulation range
3	Starch glycolate at about 0.5% to 10%	More limited but potentially easier to prove with batch records
4	No cross-linked PVP	Excludes crospovidone from the claimed tablet
5	Spray-dried mannitol	Targets a specific mannitol grade or manufacturing form
6	Fentanyl citrate	Narrows the salt limitation to a commercially common fentanyl form
7	Tablet packaged in an F1 package	Adds a packaging limitation

Claim 4 and cross-linked PVP

Claim 4 requires that the tablet not include cross-linked PVP, commonly known as crospovidone. This negative limitation can complicate infringement analysis. A product containing crospovidone would likely avoid literal infringement of claim 4, but it could still infringe claim 1 or another claim unless cross-linked PVP is otherwise relevant to the broader family.

Claim 7 and F1 packaging

Claim 7 requires an F1 package. The legal meaning of “F1 package” depends on the patent specification and prosecution record. Packaging claims are often more difficult to enforce when the package designation is an internal or specification-defined term rather than a universally recognized industry category.

Claim 7 is unlikely to be the principal barrier to a competing product because a manufacturer may be able to use a different package configuration while continuing to market a functionally equivalent tablet. Its value is greater when the package is tied to moisture protection, dose integrity, child resistance, or product stability.

How strong is the patent scope of U.S. 8,092,832?

The patent has moderate claim specificity and limited breadth.

Strengths

The claim combines multiple formulation and performance limitations. A competitor must account for all of the following:

The listed fentanyl dose;
The acid-bicarbonate effervescent system;
The separate carbonate;
Starch glycolate;
Mannitol;
Buccal suitability; and
Sub-30-minute dwell time.

The combination may be difficult to invalidate based solely on an isolated reference to fentanyl buccal delivery. A prior-art reference must disclose, or render obvious, the claimed combination and the relevant ranges.

The dependent claims also provide narrower positions directed to common commercial details, including fentanyl citrate, spray-dried mannitol, and defined starch glycolate concentrations.

Weaknesses

The claim is vulnerable to prior art directed to rapidly disintegrating fentanyl tablets, effervescent oral transmucosal systems, or Cima-type porous and effervescent dosage forms. The more closely the asserted formulation resembles earlier fentanyl buccal technology, the greater the obviousness risk.

The many numerical ranges also create validity and infringement issues. The patent owner would need to establish that the ranges are supported, technically meaningful, and not merely arbitrary selections from known formulation practice.

The “about” language can expand practical scope, but it also creates boundary disputes. The requirement that the carbonate be distinct from the food acid and bicarbonate may provide a clear design-around route.

What patents are associated with the fentanyl buccal tablet landscape?

The relevant patent landscape includes five groups.

Foundational fentanyl oral-transmucosal patents

Earlier patents cover fentanyl delivery through the oral mucosa, including lozenges, tablets, rapidly dissolving dosage forms, and effervescent systems. These patents establish the technical background against which U.S. 8,092,832 should be assessed.[1]

OraVescent and effervescent delivery patents

Cima Laboratories developed oral transmucosal delivery systems using effervescence to promote drug release and mucosal absorption. Cephalon later commercialized Fentora, a fentanyl buccal tablet using this technology. The relevant family includes patents directed to composition, dosage form structure, delivery performance, and methods of treating breakthrough pain.

Product and formulation patents for Fentora

Fentora was approved by the FDA as a fentanyl buccal tablet for breakthrough pain in opioid-tolerant patients with cancer. The FDA label identifies fentanyl citrate as the active ingredient and describes buccal administration and multiple dose strengths.[2]

Patents potentially relevant to the branded product include:

Patent category	Typical protected subject matter
Composition patents	Fentanyl plus effervescent and pH-modifying excipients
Dosage-form patents	Tablet structure, disintegration, and mucosal delivery
Method-of-use patents	Treatment of breakthrough cancer pain in opioid-tolerant patients
Manufacturing patents	Compression, granulation, coating, and stability processes
Packaging patents	Moisture protection, unit-dose packaging, and child-resistant formats

Orange Book-listed patents

The Orange Book is the controlling FDA source for patents listed against an approved drug product. Listing status can change through delisting, expiration, patent-term adjustment, FDA corrections, or product-specific regulatory events.[3]

U.S. 8,092,832 should not be treated as an Orange Book barrier solely because it covers a formulation similar to Fentora. The practical Hatch-Waxman significance depends on whether the patent was listed against the relevant NDA, whether the listing remained active when an ANDA was filed, and whether the ANDA applicant made a Paragraph IV certification.

Method-of-use patents

Method-of-use patents can remain commercially relevant even when formulation patents are weak. For fentanyl buccal tablets, method claims may cover breakthrough pain treatment, opioid-tolerant patients, dose titration, or administration protocols.

An ANDA applicant may seek a section viii statement excluding a patented indication from its labeling rather than challenge every method-of-use patent. That strategy depends on whether the patented use can be carved out without leaving an infringing label.

When does U.S. 8,092,832 lose exclusivity?

The patent issued Jan. 10, 2012. Its expiration date is determined by the earliest effective U.S. nonprovisional priority date, subject to patent-term adjustment, terminal disclaimers, and any applicable patent-term extension. The issue date alone does not establish the expiration date.[1][4]

For business planning, the relevant dates are:

Event	Date or rule
Patent issuance	Jan. 10, 2012
Standard term	20 years from the earliest effective nonprovisional filing date
Possible adjustment	USPTO patent-term adjustment
Possible limitation	Terminal disclaimer or prosecution-history effect
Drug exclusivity	Separate from patent term and controlled by FDA exclusivity rules
ANDA timing	Governed by Orange Book listing and Hatch-Waxman certification rules

A patent may remain enforceable after FDA exclusivity ends. Conversely, FDA exclusivity may expire before the patent. The two regimes must be analyzed separately.

What is the Paragraph IV challenge risk?

A generic applicant challenging an Orange Book-listed patent may file a Paragraph IV certification asserting that the patent is invalid, unenforceable, or not infringed. The NDA holder may then bring an infringement action under 35 U.S.C. §271(e)(2), potentially triggering a 30-month stay of FDA approval under the Hatch-Waxman framework.[5]

For a product modeled on the supplied claims, likely Paragraph IV positions include:

The product does not contain a distinct carbonate pH adjuster.
The effervescent system does not contain both a food acid and bicarbonate.
The starch glycolate concentration falls outside the claimed range.
The product uses a non-mannitol filler.
The product has a different dose.
The product is intended for sublingual, swallowed, or other administration.
The dwell-time limitation is not met.
The claims are obvious over earlier fentanyl oral-transmucosal and effervescent formulations.
The claims lack adequate written-description or enablement support for the full ranges.
The asserted patent is not properly listed for the relevant NDA or product.

The strongest noninfringement strategy is usually formulation-based. Replacing starch glycolate, eliminating the separate carbonate, or using a non-mannitol diluent could avoid several claim elements at once.

What generic launch scenarios exist?

Scenario 1: Same active ingredient, different formulation

A manufacturer uses fentanyl citrate but replaces starch glycolate and mannitol with other excipients. This could avoid literal infringement of claim 1 while retaining a buccal product profile.

Scenario 2: Same formulation architecture, different dose

A product uses the claimed excipients but launches at an unlisted dose. This reduces literal infringement risk but does not eliminate equivalents or other-family-patent exposure.

Scenario 3: Different transmucosal route

A sublingual or buccal film could avoid the tablet limitation. It may still face separate patents covering fentanyl transmucosal delivery, films, or methods of use.

Scenario 4: Carved-out indication

A generic applicant may seek approval for an unpatented indication if the FDA label can omit the patented use. This approach is more difficult where the product’s only commercially meaningful use is the patented indication.

Scenario 5: Formulation challenge

A generic applicant reproduces the branded formulation and files Paragraph IV certifications. This creates the highest litigation exposure because the product may satisfy the composition and functional limitations directly.

Which companies may challenge the fentanyl buccal tablet estate?

Potential challengers are manufacturers with opioid, hospital, specialty-pharmaceutical, or oral-transmucosal development capabilities. A definitive list of actual challengers requires current ANDA records, Paragraph IV notices, court dockets, and Orange Book data.

The competitive landscape includes:

Generic opioid manufacturers;
Specialty pain companies;
Companies developing buccal films or tablets;
Manufacturers of fentanyl lozenges and transmucosal systems; and
Contract developers with controlled-substance manufacturing capacity.

The main commercial barrier is not only patent scope. Fentanyl is a controlled substance, and manufacturing, distribution, quota management, diversion controls, serialization, and DEA compliance materially affect entry economics.

What FDA and commercial factors affect the patent landscape?

Fentora was approved for breakthrough pain in opioid-tolerant adult patients with cancer. Its labeling contains important safety restrictions because of respiratory depression, misuse, abuse, addiction, and accidental exposure risks.[2]

A competing product must address:

ANDA or 505(b)(2) pathway selection;
Bioequivalence or comparative pharmacokinetic requirements;
Buccal absorption and exposure;
Dose proportionality;
Controlled-substance manufacturing;
Risk-management and labeling requirements;
Child-resistant and unit-dose packaging; and
Patent certifications and potential litigation.

Biosimilar risk is not material to this product because fentanyl is a small-molecule active ingredient, not a biologic. The relevant competitive risk is generic or hybrid 505(b)(2) entry, not biosimilar substitution.

How does U.S. 8,092,832 compare with broader fentanyl patents?

Patent type	Breadth	Main risk
Broad fentanyl transmucosal patent	Potentially broad	Earlier expiration or validity pressure
Effervescent fentanyl formulation patent	Medium	Covers acid-bicarbonate delivery systems
U.S. 8,092,832	Narrow to medium	Requires a specific excipient and performance combination
Method-of-use patent	Indication-specific	Can support litigation despite formulation changes
Packaging patent	Narrow	Usually easier to design around
Manufacturing patent	Process-specific	Risk depends on actual production route

U.S. 8,092,832 is strongest when asserted against a close Fentora-style tablet. It is weaker against a different dosage form, a non-effervescent formulation, a product without starch glycolate, or a formulation using a different diluent system.

Key Takeaways

U.S. 8,092,832 is a combination claim directed to a fentanyl buccal tablet, not a broad fentanyl monopoly.
Claim 1 requires all major elements: listed fentanyl dose, food acid, bicarbonate, separate carbonate, starch glycolate, mannitol, buccal delivery, and dwell time below about 30 minutes.
Claims 2 and 3 narrow starch glycolate concentration; claim 4 excludes cross-linked PVP; claim 5 specifies spray-dried mannitol; claim 6 specifies fentanyl citrate; and claim 7 adds F1 packaging.
The most credible design-around routes involve replacing starch glycolate, eliminating the separate carbonate, replacing mannitol, changing the dosage form, or changing the administration route.
Orange Book listing must be assessed separately from technical claim coverage.
Paragraph IV risk is highest for a generic tablet that copies the Fentora formulation architecture.
Biosimilar risk is not relevant because fentanyl is a small molecule.
Exact patent expiration requires the complete priority, prosecution, patent-term-adjustment, and terminal-disclaimer record.

FAQs

Does U.S. 8,092,832 cover all fentanyl buccal tablets?

No. It covers only tablets meeting the full combination of claim limitations, including the specified excipients, dose levels, buccal use, and dwell-time requirement.

Can a fentanyl tablet avoid the patent by using crospovidone?

Potentially. Crospovidone may avoid claim 4 because that claim excludes cross-linked PVP. It does not automatically avoid claim 1 unless the product also lacks starch glycolate or another required limitation.

Is fentanyl citrate independently protected by claim 6?

Claim 6 specifically narrows the tablet to fentanyl citrate. It does not mean that every fentanyl citrate product infringes. The tablet must first satisfy the limitations inherited from claim 1.

Can a fentanyl buccal film avoid U.S. 8,092,832?

A film may avoid the tablet limitation, but separate patents covering buccal films, fentanyl transmucosal delivery, methods of use, or manufacturing may still apply.

Is FDA approval blocked when the patent expires?

No. FDA approval timing depends on the applicable regulatory exclusivity, Orange Book certifications, litigation stay, and other patents. Patent expiration is only one part of the entry analysis.

References

United States Patent and Trademark Office. (2012). U.S. Patent No. 8,092,832, fentanyl compositions and methods of use.
U.S. Food and Drug Administration. (n.d.). Fentora prescribing information.
U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations: Orange Book.
United States Patent and Trademark Office. (n.d.). Patent term adjustment and patent term calculation guidance.
Drug Price Competition and Patent Term Restoration Act of 1984, 21 U.S.C. § 355(j); 35 U.S.C. § 271(e)(2).

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
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Argentina	098347	⤷ Start Trial
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Austria	500821	⤷ Start Trial
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Summary for Patent: 8,092,832