U.S. Patent 7,910,132: Fentanyl Sublingual Tablet Claims, Expiration, Litigation Risk, and Patent Landscape

U.S. Patent No. 7,910,132 covers methods of treating breakthrough pain with a sublingual fentanyl tablet. Its core limitations are a tablet placed under the tongue, fentanyl particles with a maximum weight-based mean particle size of about 24 micrometers, a bioadhesive or mucoadhesive agent, and rapid mucosal uptake within about five minutes. The patent does not broadly claim fentanyl, sublingual administration, or a tablet composition without these limitations.

The patent’s commercial relevance is associated with sublingual fentanyl products such as Abstral, although product protection depends on the complete Orange Book listing and the scope of related continuation patents. The patent term has ended based on the 20-year term measured from the earliest effective filing date, subject to any recorded patent-term adjustment or extension. As a result, U.S. Patent 7,910,132 does not presently provide an enforceable exclusionary right.

What does U.S. Patent 7,910,132 protect?

The patent protects a treatment method rather than a standalone drug composition. Each enforceable claim requires a patient with breakthrough pain who is already receiving at least one analgesic for baseline pain.

The claimed treatment uses:

Claim element	Required limitation
Patient population	Individual receiving at least one analgesic and experiencing breakthrough pain
Active ingredient	Fentanyl or a pharmaceutically acceptable salt
Dosage form	Tablet sized for placement under the tongue
Fentanyl particle size	Maximum weight-based mean particle size of about 24 micrometers
Adhesion technology	Bioadhesive or mucoadhesive agent
Route	Sublingual administration
Pharmacokinetic result	Uptake through the sublingual mucosa within about five minutes
Optional salt	Fentanyl citrate under claim 10
Optional fentanyl amount	0.05 to 20 mg per dose unit
Optional fentanyl concentration	0.05% to 20% by weight
Optional adhesive particle size	Approximately 1 to 100 micrometers
Optional adhesive concentration	Approximately 0.1% to 25% by weight

The central inventive concept is the combination of particle-size control and mucosal adhesion in a sublingual fentanyl tablet intended to provide rapid relief of breakthrough pain.

How many independent claims does U.S. Patent 7,910,132 have?

The patent has four independent method claims: claims 1, 3, 7, and 8.

Claim 1

Claim 1 requires the sublingual fentanyl tablet, fentanyl particle-size limitation, adhesion agent, breakthrough-pain treatment, and uptake within about five minutes. It does not specify a fentanyl dose or adhesive concentration.

Claim 3

Claim 3 adds a dose-unit limitation requiring between approximately 0.05 mg and 20 mg of fentanyl or fentanyl salt. It otherwise tracks claim 1.

Claim 7

Claim 7 requires the dose-unit range and also requires the adhesive agent to have particles between approximately 1 and 100 micrometers.

Claim 8

Claim 8 requires the 24-micrometer fentanyl particle limitation, the 1-to-100-micrometer adhesive particle range, and the 0.1% to 25% adhesive concentration. It does not require the 0.05-to-20 mg fentanyl dose range.

Claims 2, 4, 5, 6, 9, 10, and 11 are dependent claims. Claim 10 narrows the active ingredient to fentanyl citrate. Claim 11 adds the fentanyl concentration range to claim 8.

What formulations are protected by U.S. Patent 7,910,132?

The patent reaches a narrow formulation profile rather than every sublingual fentanyl product.

A potentially covered product would generally need to have all of the following:

Fentanyl or a pharmaceutically acceptable fentanyl salt.
A tablet designed for sublingual placement.
Fentanyl particles with a maximum weight-based mean particle size of about 24 micrometers.
A bioadhesive or mucoadhesive excipient.
Use to treat breakthrough pain in a patient receiving baseline analgesia.
Rapid mucosal uptake within approximately five minutes.

Depending on the asserted claim, the product may also need:

0.05 to 20 mg of fentanyl per dose unit;
0.05% to 20% fentanyl by weight;
adhesive particles between 1 and 100 micrometers;
adhesive concentration between 0.1% and 25% by weight; or
fentanyl citrate rather than another fentanyl salt.

A sublingual fentanyl product could avoid literal infringement if its fentanyl particle distribution does not meet the claimed approximately 24-micrometer threshold, if it lacks the claimed adhesive agent, or if its approved use does not involve breakthrough pain in patients receiving baseline opioid therapy. Avoidance would depend on the actual product, manufacturing process, labeling, and claim construction.

How should “about 24 micrometers” be interpreted?

The particle-size limitation is likely to be a principal validity and infringement issue.

The claims refer to a “maximum weight based mean particle size of about 24 μm.” That language raises several technical questions:

Whether “about 24 μm” means an upper limit near 24 μm or a target value centered on 24 μm.
Whether the measurement is based on a volume-weighted or mass-weighted distribution.
Which analytical method is used.
Whether agglomerated particles are measured as individual particles or aggregates.
Whether the claim requires every batch to satisfy the limit.
Whether the specification defines a tolerance around 24 μm.

“About” generally provides some flexibility, but it does not eliminate the need for an objectively reproducible measurement. A challenger could argue that the term is indefinite if the specification and prosecution history do not provide a reliable boundary. The patent owner would likely argue that a skilled pharmaceutical formulator could determine compliance using conventional particle-size analysis.

The same issue applies to the “within about five minutes” uptake limitation. The limitation may be treated as a product-performance requirement, a treatment-method result, or both, depending on the claim construction and evidence.

Does U.S. Patent 7,910,132 claim Abstral?

The claim language is consistent with the technical profile of Abstral, a fentanyl citrate sublingual tablet approved by the FDA for the management of breakthrough pain in adults with cancer who are already receiving and tolerant to around-the-clock opioid therapy. Abstral was approved under NDA 022510.[2]

The patent does not name Abstral in the claims. A branded product is covered only if its formulation, particle size, dosage, labeling, and clinical use satisfy each limitation of an asserted claim.

The FDA labeling for Abstral identifies it as a sublingual tablet containing fentanyl citrate. The product was approved in multiple strengths, including 100, 200, 300, 400, 600, and 800 micrograms. Those strengths fall within the broad dose range recited in claims 3 and 7, but the existence of a matching dose alone does not establish infringement.[2]

What is the Orange Book status of U.S. Patent 7,910,132?

U.S. Patent 7,910,132 was associated with the Abstral product’s U.S. patent listing and related regulatory exclusivity analysis. The Orange Book distinguishes patents covering drug substances, drug products, and methods of use. A method-of-use patent generally affects an ANDA applicant through the certification process rather than by creating a composition patent that blocks every use of the active ingredient.[1]

For an ANDA applicant, a listed method patent can trigger:

Paragraph III certification, accepting delayed approval until patent expiry;
Paragraph IV certification, asserting that the patent is invalid, unenforceable, or not infringed; or
a section viii statement carving out the patented method, where the remaining labeling supports approval.

Because the patent term has ended, U.S. Patent 7,910,132 no longer creates a current Paragraph IV launch barrier. A commercial launch may still be constrained by other live patents, regulatory exclusivity, controlled-substance requirements, manufacturing controls, or separate formulation patents.

When did U.S. Patent 7,910,132 lose exclusivity?

The patent’s effective filing history controls the expiration date. Under 35 U.S.C. § 154, a utility patent generally expires 20 years from the earliest effective nonprovisional filing date, subject to patent-term adjustment and other statutory modifications.[3]

U.S. Patent 7,910,132 is now beyond its standard enforceable term. The patent therefore cannot support a new infringement action for post-expiration conduct. Historical infringement claims accruing during the enforceable term may remain subject to applicable limitation periods, estoppel, settlement terms, and other procedural defenses.

The patent should be analyzed separately from any later-issued continuation or divisional patents. A continuation may share the same effective filing date but contain different claims. Its expiration generally remains tied to the parent application’s earliest effective nonprovisional filing date, although patent-term adjustment can differ.

What are the strongest and weakest claim limitations?

Strongest commercial limitation

The combined requirement for a sublingual tablet, fentanyl particle size of about 24 micrometers, and bioadhesive or mucoadhesive excipient creates a product-specific technical combination. A competing manufacturer may not be able to determine compliance solely from the public label.

Strongest infringement evidence

The strongest evidence would include:

batch manufacturing records;
particle-size specifications;
certificates of analysis;
excipient composition;
formulation development reports;
dissolution and mucosal-uptake studies;
regulatory submissions; and
the approved labeling and prescribing information.

Weakest claim limitations

The likely pressure points are:

“about 24 μm”;
“within about five minutes”;
“bioadhesion and/or mucoadhesion promoting agent”;
the boundary between a therapeutic-use limitation and a product-performance limitation; and
whether the patient population is sufficiently defined by the requirement for baseline analgesic therapy.

A validity challenge could focus on anticipation or obviousness based on earlier fentanyl transmucosal products, sublingual tablets, particle-size optimization, and mucoadhesive excipients. The patent owner would respond that the claimed combination produced a clinically useful rapid-onset profile and that the prior art did not disclose the complete combination.

How does this patent compare with competing fentanyl patent estates?

Product or technology	Route	Typical patent focus	Relationship to U.S. 7,910,132
Abstral	Sublingual tablet	Fentanyl citrate, particle size, adhesion, rapid uptake	Closest commercial association
Actiq	Oral transmucosal lozenge	Lozenge delivery and transmucosal administration	Different dosage form and route mechanics
Fentora	Buccal tablet	Effervescent or buccal delivery technology	Different mucosal site and formulation architecture
Subsys	Sublingual spray	Spray delivery and sublingual administration	Same general mucosal route, different dosage form
Lazanda	Intranasal spray	Nasal delivery and absorption	Outside the claimed sublingual tablet scope
Generic fentanyl products	Varies	Product-specific formulation and labeling	Risk depends on formulation and use code

The patent is narrower than a broad fentanyl-use patent and narrower than a basic sublingual delivery patent. Its value depended on the ability to connect a specific formulation architecture to the approved breakthrough-pain indication.

What generic launch risks existed under the patent?

During the patent term, a generic applicant seeking approval for a substantially equivalent sublingual fentanyl tablet would have faced several possible strategies.

Paragraph IV challenge

The applicant could assert that the patent was invalid, unenforceable, or not infringed. The principal technical arguments would likely involve:

prior-art sublingual fentanyl tablets;
prior-art mucoadhesive excipients;
routine particle-size optimization;
indefiniteness of “about 24 μm”;
lack of written description for the full scope; and
failure to demonstrate that the claimed particle size produces the claimed rapid uptake.

Section viii carve-out

If the listed patent covered only breakthrough pain in opioid-tolerant patients, an applicant might attempt to omit the patented indication from its labeling. This strategy would depend on whether the remaining labeling could support approval without encouraging the patented use.

Design-around formulation

A manufacturer could pursue:

a different fentanyl particle-size distribution;
a nonadhesive or differently functioning excipient;
a buccal rather than sublingual product;
a spray, film, lozenge, or other dosage form;
a different active salt; or
a formulation with a different uptake profile.

Design-around analysis must consider the doctrine of equivalents, especially where changes are insubstantial and perform substantially the same function in substantially the same way.

Which companies challenged or could challenge the patent?

Generic companies seeking approval for sublingual fentanyl products would have been the relevant challengers. A Paragraph IV dispute would normally involve the NDA holder or patent owner, an ANDA applicant, and potentially the FDA following the statutory litigation stay.

Public regulatory records should be reviewed for the specific Orange Book patent certification history, litigation docket, settlement agreement, and any authorized generic arrangement. The patent text alone does not establish whether a particular company filed a Paragraph IV certification, whether litigation occurred, or whether the parties entered into a settlement.

No biosimilar pathway applies. Fentanyl is a chemically synthesized small molecule, so competitive entry proceeds through the ANDA pathway or, for materially different products, an NDA pathway. Biosimilar risk is therefore not relevant to this patent family.

What licensing and settlement issues matter?

The principal commercial issues are ownership, NDA sponsorship, marketing rights, and any settlement restricting generic entry.

Relevant documents include:

assignments recorded with the USPTO;
the NDA ownership and sponsor history;
license agreements between the formulation patent owner and the product sponsor;
Paragraph IV notices;
Hatch-Waxman litigation complaints;
consent judgments;
settlement agreements; and
authorized-generic arrangements.

A settlement could have delayed generic entry beyond the patent’s nominal expiration or permitted an earlier launch under specified conditions. The patent number itself does not disclose those commercial terms.

Does the patent create manufacturing or geographic barriers?

The patent’s practical manufacturing barrier was stronger than its current legal barrier.

During the enforceable term, a competing manufacturer would have needed to control:

fentanyl particle-size milling or classification;
uniform distribution of a potent opioid in low-dose tablets;
adhesive-excipient particle sizing;
content uniformity;
sublingual disintegration;
rapid dissolution;
dose proportionality; and
controlled-substance manufacturing and distribution.

The patent is a U.S. right. Foreign counterpart patents would need separate analysis by jurisdiction. A U.S. patent does not prevent manufacture or sale outside the United States, and foreign patents may have different claims, expiration dates, prosecution histories, and validity outcomes.

Key Takeaways

U.S. Patent 7,910,132 claims methods using a sublingual fentanyl tablet for breakthrough pain.
Its core limitations are fentanyl particles with a maximum weight-based mean particle size of about 24 micrometers, a bioadhesive or mucoadhesive agent, and rapid uptake within about five minutes.
Claims 1, 3, 7, and 8 are independent method claims.
Claims 3 and 7 require 0.05 to 20 mg of fentanyl per dose unit.
Claims 7 and 8 require adhesive particles between approximately 1 and 100 micrometers.
Claim 10 specifically covers fentanyl citrate.
The patent is closely associated with the technical profile of Abstral, but product coverage requires claim-by-claim analysis of the commercial formulation and labeling.
The principal validity issues are particle-size measurement, the meaning of “about,” rapid-uptake evidence, written description, enablement, and obviousness.
The patent’s U.S. term has ended, so it is not a current standalone barrier to generic entry.
No biosimilar pathway applies because fentanyl is a small-molecule drug.
Current launch risk depends primarily on related patents, regulatory requirements, controlled-substance controls, and any historical settlement or licensing restrictions.

FAQs About U.S. Patent 7,910,132

Does U.S. Patent 7,910,132 cover all fentanyl sublingual tablets?

No. The claims require specific particle-size, adhesion, dosage-form, patient-use, and rapid-uptake limitations.

Is U.S. Patent 7,910,132 a composition patent?

No. The issued claims provided are method-of-treatment claims. They do not independently claim a pharmaceutical composition without the required treatment and administration steps.

Can a fentanyl buccal tablet infringe this patent?

A buccal tablet would generally avoid the express requirement for a tablet placed under the tongue, although infringement depends on the actual administration instructions and claim construction.

Does a fentanyl nasal spray fall within the claims?

Generally no. The claims require sublingual administration through mucous membrane under the tongue.

Is a new Paragraph IV challenge available against an expired patent?

No current Paragraph IV challenge is needed to overcome an expired patent. An ANDA applicant may still need to address other unexpired patents listed for the relevant reference product.

References

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. (2010). Abstral prescribing information: Fentanyl citrate sublingual tablets, NDA 022510. https://www.accessdata.fda.gov/drugsatfda/
United States Code. (2024). 35 U.S.C. § 154: Contents and term of patent; provisional rights. https://uscode.house.gov/view.xhtml?req=granuleid:USC-prelim-title35-section154
United States Patent and Trademark Office. (2011). U.S. Patent No. 7,910,132, Sublingual pharmaceutical composition. https://patents.google.com/patent/US7910132B2
United States Code. (2024). 35 U.S.C. §§ 271 and 282: Patent infringement and presumptions of validity. https://uscode.house.gov/view.xhtml?path=/prelim@title35&edition=prelim

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
Sweden	9803240	Sep 24, 1998

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
European Patent Office	2236132	⤷ Start Trial	C300714	Netherlands	⤷ Start Trial
European Patent Office	2236132	⤷ Start Trial	CA 2015 00004	Denmark	⤷ Start Trial
European Patent Office	2236132	⤷ Start Trial	92636	Luxembourg	⤷ Start Trial
European Patent Office	2236132	⤷ Start Trial	122015000006	Germany	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 7,910,132

Summary for Patent: 7,910,132