US Patent 7,348,362: Formoterol Nebulizer Solution Claims, Expiration, Orange Book Status and Generic Risk

US Patent 7,348,362 covers sterile, preservative-free or otherwise sterile unit-dose formoterol solutions packaged for nebulizer administration. Its core limitations are a narrow concentration range, acidic buffered aqueous formulation, unit-dose packaging, stability performance, and direct administration without dilution. The patent was assigned to Dey, L.P., the developer of Perforomist, and was granted on March 25, 2008.[1]

The patent’s 20-year term ran from its earliest nonprovisional priority date and expired in 2023, subject to any applicable patent-term adjustment. It therefore does not create a current US blocking right against generic formoterol inhalation solution products. Its historical importance was greater than its present exclusionary value because it covered the commercial formulation architecture used for Perforomist.

What does US Patent 7,348,362 protect?

The patent protects a combination of formulation, packaging, stability, and administration limitations rather than formoterol as a molecule.

Its central claim elements are:

Claim element	Scope in US 7,348,362
Active ingredient	Formoterol or a salt, including formoterol tartrate
Formoterol concentration	Approximately 0.08 to 34 micrograms/mL, measured as formoterol free base
Narrower concentration	Approximately 0.08 to 26 micrograms/mL in claims 3, 4 and 10
Dosage volume	Approximately 0.1 to 3.0 mL; approximately 2 mL in the narrower claims
Vehicle	Water and a pharmacologically suitable solution
Buffer	Citrate/phosphate, acetate, citrate or phosphate
Buffer concentration	Approximately 1 to 20 mM, 5 to 20 mM, or up to 50 mM depending on the claim
pH	Approximately 4.5 to 5.5, or approximately pH 5
Package	Vial, blister, bottle, tube, bag, syringe or other pharmaceutical package
Packaging refinement	Vial overwrapped with a laminate
Administration	Direct addition to a nebulizer without dilution or modification
Stability limitation	Specified retained formoterol percentage after storage under defined conditions
Optional excipient	Tonicity-adjusting agent, including sodium chloride
Stereochemistry	R-form formoterol and tartrate salt in dependent claims

The patent does not claim every formoterol solution. A potentially infringing product must satisfy all limitations of at least one asserted claim. A formulation outside the claimed concentration, pH, buffer, package, volume, or administration conditions may avoid literal infringement, although the doctrine of equivalents could have been relevant during the patent’s enforceable term.

How are the claims of US 7,348,362 structured?

Claims 1 and 2: broad sterile unit-dose formulations

Claims 1 and 2 are formulation-and-package claims.

Claim 1 requires:

0.1 to 3.0 mL of solution;
formoterol at approximately 0.08 to 34 micrograms/mL;
water;
one of four specified buffer systems;
buffer concentration of approximately 1 to 20 mM;
pH of approximately 4.5 to 5.5;
more than 90% estimated shelf life after three months at 25°C and after three years at 5°C; and
pharmaceutical packaging.

Claim 2 narrows the buffer concentration to approximately 5 to 20 mM and imposes different stability thresholds: more than approximately 94% after three months at 25°C and more than approximately 96% after three months at 5°C.

The stability language is a material claim limitation. It is not merely a product description. An accused product would ordinarily require analytical evidence concerning retained formoterol content and degradation products under the specified storage conditions.

Claims 3 and 4: two-milliliter citrate-buffered vials

Claims 3 and 4 are narrower in volume, buffer identity and packaging.

They require:

approximately 2 mL;
formoterol at approximately 0.08 to 26 micrograms/mL;
citrate buffer;
approximately pH 5;
a vial overwrapped with a laminate.

Claim 3 includes buffer concentration of approximately 1 to 20 mM and the specified stability thresholds. Claim 4 allows approximately 1 to 50 mM citrate buffer but does not expressly include the claim 3 stability limitation.

Claim 4 is commercially important because its wider buffer range may capture a greater number of citrate-buffered 2 mL vial formulations. At the same time, it remains constrained by the volume, concentration, pH, citrate-buffer, vial and laminate requirements.

Claims 5 to 7: excipient and package limitations

Claim 5 adds a tonicity-adjusting agent. Claim 6 identifies sodium chloride. Claim 7 lists possible packages, including vials, bottles, blister packs, bags and syringes.

These claims do not materially expand the patent beyond the independent claims. They create narrower fallback positions if an independent claim is challenged or if a competing product uses a specific tonicity agent or package.

Claims 8 and 9: direct nebulizer administration

Claims 8 and 9 are method claims. They require:

removing approximately 1 to 3 mL from a propellant-free sterile unit-dose package;
placing the solution in a nebulizer;
administering it directly to a patient; and
omitting dilution or other modification before administration.

Claim 9 adds the stability limitation from claim 1.

The reference to “oral administration” is best read in the context of pulmonary delivery through a nebulizer. The claimed route is not swallowing the formulation. It is administration to the respiratory tract by nebulization.

Claims 10 to 15: narrower administration and packaging claims

Claim 10 narrows the method to:

approximately 2 mL;
0.08 to 26 micrograms/mL;
citrate buffer;
approximately pH 5;
the specified stability thresholds.

Claims 11 and 12 add a tonicity agent and sodium chloride. Claims 13 to 15 address package selection and the vial-overwrapped-with-laminate configuration.

Claims 16 to 18: stereochemistry and salt form

Claims 16 through 18 narrow claim 1 to:

R-form formoterol;
a salt of R-form formoterol;
formoterol tartrate.

These dependent claims are directed to specific chemical forms. They do not claim the broader racemic formoterol universe.

What formulation is most closely associated with US 7,348,362?

The commercial formulation most closely aligned with the patent is Perforomist, a formoterol fumarate inhalation solution supplied in a 2 mL unit dose for nebulization. The marketed product is administered through a nebulizer and is supplied as a sterile, ready-to-use inhalation solution.[2]

The claim language also reaches formoterol tartrate and other salt forms. Perforomist’s commercial active ingredient is formoterol fumarate, while claims 16 to 18 expressly identify the R form and tartrate salt. The patent therefore has broader chemical coverage than the particular salt used in the branded product.

A claim chart for a typical 2 mL formoterol nebulizer solution would focus on the following issues:

Issue	Relevance
Formoterol equivalent dose	Determines whether the product falls within the free-base concentration range
Total fill volume	Separates 2 mL products from formulations outside the claimed range
Buffer identity	Citrate and citrate/phosphate systems are central
Buffer molarity	Claims differ materially between 1 to 20 mM and 1 to 50 mM
pH	Approximately pH 5 is a key limitation in claims 3, 4 and 10
Container	A vial alone may not satisfy the laminate-overwrap limitation
Sterility	Required in the unit-dose claims
Ready-to-use status	Central to the direct-administration method claims
Stability data	Required for claims containing retained-formoterol limitations

When did US Patent 7,348,362 expire?

US Patent 7,348,362 expired in 2023 based on its 20-year patent term. The exact terminal date depends on the patent’s recorded earliest priority date and any patent-term adjustment shown in the USPTO record.[1]

The patent should therefore be treated as expired for current freedom-to-operate analysis in the United States. A patent that has expired can remain relevant to historical litigation, damages periods and prosecution history, but it no longer supports an ordinary prospective infringement injunction.

Milestone	Date or status
Earliest patent priority	2002-era priority date reflected in the patent family
US grant	March 25, 2008
Patent number	US 7,348,362 B2
Nominal term	20 years from the earliest nonprovisional filing
Current status	Expired in 2023
Current blocking effect	None after expiration, absent an unusual surviving right or separate patent

What was the Orange Book status of US 7,348,362?

The patent was associated with the Perforomist NDA and was relevant to the branded product’s US patent listing history. The FDA Orange Book identifies patents submitted by NDA sponsors for approved drug products, including drug-substance, drug-product and method-of-use patents where the statutory listing criteria are met.[3]

The Orange Book listing did not mean that every formoterol nebulizer product infringed the patent. It indicated that the patent was submitted in connection with the approved reference product and could require a generic applicant to address the patent through a Paragraph IV certification while the patent remained listed and unexpired.

After expiration, the patent no longer creates a live Orange Book patent barrier to approval. The FDA’s current Orange Book data should be used to confirm whether the record is displayed as expired, delisted or otherwise inactive.[3]

Did the patent create Paragraph IV risk for generic formoterol?

Yes, while the patent was listed and unexpired, an ANDA applicant seeking approval for a formoterol fumarate inhalation solution could have faced Paragraph IV issues.

A generic applicant could challenge the patent by asserting that:

the proposed product did not meet one or more formulation limitations;
the product lacked the claimed pH or buffer concentration;
the package did not include the required laminate overwrap;
the product fell outside the concentration or volume range;
the stability limitation was not met;
the patent claims were invalid for anticipation, obviousness, lack of written description, enablement or indefiniteness; or
the proposed use did not satisfy the direct-administration limitations.

Under the Hatch-Waxman framework, a valid Paragraph IV certification can trigger patent litigation and, in some circumstances, a 30-month stay of FDA approval.[4] That mechanism is no longer a practical barrier based solely on US 7,348,362 because the patent has expired.

How strong were the claims from an infringement perspective?

The strongest historical claims were likely claims 3, 4 and 10 because they correspond closely to a commercially recognizable 2 mL ready-to-use nebulizer presentation.

Their strengths were:

clear product architecture;
specific pH and citrate-buffer requirements;
defined volume;
identifiable vial packaging;
direct relationship to a commercial unit-dose product; and
dependent claims covering sodium chloride, R-form formoterol and tartrate.

The principal weaknesses were the breadth and technical ambiguity of certain terms.

Stability limitations

“Estimated shelf life” and retained percentages after storage create proof issues. The claims do not simply recite a formulation composition. They require a performance result under specified conditions. Differences in assay method, impurity measurement, sampling time and extrapolation model could affect infringement analysis.

Approximation language

The repeated use of “about” creates ordinary claim-construction questions. A court would assess the term in the context of the specification, prosecution history and technical field. The ranges are not unlimited, but they are not mathematically exact boundaries.

Functional formulation language

“Pharmacologically suitable solution” is broad and potentially vulnerable to indefiniteness or enablement arguments if the specification did not provide adequate guidance across the full claimed range. The same applies to the formulation’s stability performance across different salts, buffers, packages and concentrations.

Package limitations

Claims 3, 4 and 10 require a vial overwrapped with a laminate. A generic product using a different moisture-barrier configuration could have had a noninfringement position even if its formulation were chemically similar.

What generic launch risks exist after patent expiration?

The principal current risk is regulatory and commercial rather than patent-based.

Generic manufacturers may pursue an ANDA for formoterol fumarate inhalation solution if they can demonstrate pharmaceutical equivalence, bioequivalence or another FDA-accepted approval basis, manufacturing consistency and appropriate device compatibility. The product must also comply with sterile manufacturing and container-closure requirements.

Relevant barriers include:

sterile liquid manufacturing;
control of formoterol degradation;
container-closure integrity;
low-dose content uniformity;
compatibility with nebulizers;
preservative and microbial-control strategy;
stability data;
FDA product-specific guidance; and
commercial access to unit-dose vial filling and laminate overwrapping.

These are manufacturing and regulatory barriers, not surviving exclusivity rights under US 7,348,362.

Are biosimilar risks relevant to formoterol?

No. Formoterol is a small-molecule active pharmaceutical ingredient, not a biologic. A competing product would proceed through the generic-drug framework, principally an ANDA under section 505(j) of the Federal Food, Drug, and Cosmetic Act, rather than the biosimilar pathway under section 351(k) of the Public Health Service Act.[4,5]

The competitive risk is therefore generic substitution, not biosimilar interchangeability.

How does US 7,348,362 compare with competing formoterol patent estates?

Product or technology	Active ingredient	Delivery	Relationship to US 7,348,362
Perforomist	Formoterol fumarate	Nebulized inhalation solution	Closest commercial product
Foradil	Formoterol fumarate	Dry-powder inhalation capsule/device	Different dosage form and device architecture
Brovana	Arformoterol tartrate	Nebulized inhalation solution	Different active stereochemical product
Generic formoterol solution	Formoterol salt	Nebulized solution	Main post-expiration competitor
Formoterol metered-dose or dry-powder products	Formoterol salt	Inhaler	Generally outside the unit-dose nebulizer claims

The patent does not control all formoterol delivery systems. Dry-powder inhalers, metered-dose inhalers and arformoterol products rely on different active ingredients, dosage forms, devices and patent families.

What licensing and litigation issues matter?

The commercial patent owner was Dey, L.P., later associated with the broader Mylan/Viatris commercial organization. Product rights and commercial arrangements may have involved NDA sponsorship, manufacturing, distribution or later corporate transactions, but US 7,348,362 should not be treated as an active licensing asset after expiration.

The patent’s historical value was tied to Perforomist’s launch and protection of a ready-to-use nebulizer solution. Any historical litigation assessment should distinguish:

cases involving this patent specifically;
cases involving other formoterol or inhalation patents;
ANDA disputes involving Perforomist;
settlement agreements with generic applicants; and
litigation concerning device, manufacturing or regulatory exclusivity rather than formulation claims.

No current injunction or live Paragraph IV block can be inferred from the patent number alone after expiration.

What is the current commercial exposure?

The principal revenue exposure was Perforomist sales during the patent term. Since expiration, the risk is erosion from generic formoterol nebulizer solutions and therapeutic substitution from alternative long-acting bronchodilators.

Commercial exposure depends on:

the share of patients using nebulized rather than inhaler-based therapy;
payer substitution policies;
generic price discounts;
availability of unit-dose manufacturing capacity;
physician preference for ready-to-use products;
competing arformoterol solutions; and
device and pharmacy distribution arrangements.

The patent itself no longer supports a premium based on exclusivity. Any continuing brand differentiation must come from formulation reliability, device compatibility, supply, contracting or clinical positioning.

Key Takeaways

US 7,348,362 covers sterile unit-dose formoterol solutions for nebulizer use.
Its core limitations are concentration, pH, buffer, volume, sterility, packaging and, in several claims, stability performance.
Claims 3, 4 and 10 most closely track a 2 mL citrate-buffered vial overwrapped with laminate.
Claims 8 to 10 require direct nebulizer administration without dilution or modification.
Claims 16 to 18 narrow the invention to R-form formoterol and tartrate salt embodiments.
The patent expired in 2023 and is no longer a current US exclusionary barrier.
Formoterol is a small molecule, so biosimilar analysis does not apply.
Current generic risk is driven by ANDA approval, sterile manufacturing and market access rather than this expired patent.
Separate device, formulation, method-of-use or manufacturing patents would need independent review before a complete freedom-to-operate conclusion.

FAQs

Can a generic formoterol nebulizer solution still infringe US 7,348,362?

A product could have infringed during the patent’s enforceable term if it met every limitation of an asserted claim. After expiration, ordinary prospective infringement liability under this patent is no longer available.

Does a 2 mL vial automatically fall within the patent?

No. The product would also need to satisfy the applicable active-ingredient concentration, citrate-buffer, pH, sterility, packaging and other claim limitations.

Does the patent cover formoterol fumarate?

The claims cover formoterol or a salt thereof. The patent is not limited to formoterol fumarate, although the commercial Perforomist product uses formoterol fumarate.

Is arformoterol covered by this patent?

Not necessarily. Arformoterol is a distinct active ingredient and should be analyzed against the claims, specification and prosecution history. A product-specific infringement analysis would be required.

Can a company launch a generic after the patent expires without a Paragraph IV challenge?

Yes, assuming no other unexpired listed patent, regulatory exclusivity period, injunction or separate patent family blocks approval. The expired patent itself does not require a current Paragraph IV challenge.

References

United States Patent and Trademark Office. (2008). US Patent No. 7,348,362 B2: Formoterol compositions and methods of use.
U.S. Food and Drug Administration. (2007). Perforomist (formoterol fumarate) inhalation solution prescribing information.
U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations: Orange Book.
Federal Food, Drug, and Cosmetic Act, 21 U.S.C. § 355(j).
Public Health Service Act, 42 U.S.C. § 262(k).

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
European Patent Office	1660035	⤷ Start Trial
Taiwan	200507830	⤷ Start Trial
Taiwan	I359675	⤷ Start Trial
World Intellectual Property Organization (WIPO)	2005007142	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 7,348,362

Summary for Patent: 7,348,362