US Patent 8,623,922: Scope, Claim Construction, Expiration Risk, and Formoterol Patent Landscape

US Patent 8,623,922 protects an aqueous, stable formoterol composition for inhalation or nebulization at a broad concentration range of approximately 0.08 to 128 micrograms per milliliter, measured as formoterol free base. The patent’s commercial significance is concentrated in the formulation platform rather than in the formoterol molecule itself. Its claims combine four principal limitations: formoterol or a broad range of derivatives, water-containing pharmaceutical fluid, long-term stability, and specified concentration, with dependent claims covering buffers, tonicity agents, ionic strength and nebulization.

The claim set is potentially relevant to nebulized formoterol products, including formulations containing formoterol fumarate or another pharmaceutically acceptable form of formoterol. Infringement would depend on the marketed product’s actual concentration, formulation composition, storage stability data and use or labeling.

What does US Patent 8,623,922 claim?

Claim 1 is the controlling composition claim. It requires all of the following:

Claim 1 limitation	Scope
Active ingredient	Formoterol or a pharmaceutically acceptable derivative
Covered derivatives	Salts, esters, enol ethers, enol esters, acids, bases, solvates, hydrates and prodrugs
Vehicle	A pharmacologically suitable fluid
Water	The fluid comprises water
Stability	The composition is stable during long-term storage
Concentration	Approximately 0.08 to approximately 128 micrograms/mL of formoterol free base

The claim is drafted as a composition claim. It does not require a nebulizer, a particular device, a specific buffer, a particular salt, a defined pH or a particular dosage regimen.

The broadest practical limitation is the combination of aqueous formulation, stability and concentration. The claim does not cover every formoterol-containing product. A product lacking water, falling outside the stated concentration range, or failing the stability limitation would have a potential noninfringement position, subject to claim construction and equivalents analysis.

How broad is the formoterol derivative language?

The derivative language is expansive. It expressly covers:

Formoterol free base
Formoterol salts, including fumarate salts
Solvates and hydrates
Esters and prodrugs
Acidic and basic forms
Enol ethers and enol esters

This language attempts to prevent design-around strategies based solely on changing the chemical form of formoterol. A manufacturer generally could not avoid the claim merely by using formoterol fumarate instead of free-base formoterol if the salt is a pharmaceutically acceptable derivative and the claimed concentration is converted or expressed as free-base equivalent.

The phrase “selected from the group consisting of” is also significant. It generally indicates a closed Markush group for the listed derivative categories, although the categories themselves are broad.

What concentration range does US 8,623,922 protect?

Claim 1 covers approximately 0.08 to approximately 128 micrograms/mL of formoterol free base.

The range has an unusually broad span:

Lower boundary	Upper boundary	Approximate span
0.08 micrograms/mL	128 micrograms/mL	1,600-fold

The concentration must be assessed on a free-base basis. A product label stating formoterol fumarate concentration may not be directly comparable to the claim. The relevant analysis requires conversion from salt mass to formoterol free-base mass.

The concentration limitation creates several potential infringement issues:

Whether the product concentration is inside the literal range.
Whether the concentration is expressed as salt or free base.
Whether “about” allows a tolerance around the endpoints.
Whether the claimed range is measured before storage, after storage or at another specified stage.
Whether a single-dose product is diluted before nebulization.
Whether a ready-to-use formulation and a concentrate are analyzed separately.

A product at or near 0.08 or 128 micrograms/mL would require particular attention to the meaning of “about.” The patent does not define the numerical tolerance in the claims supplied.

What stability requirements are imposed by the dependent claims?

Claims 2 and 3 add objective stability requirements.

Claim	Stability limitation
1	Stable during long-term storage
2	Estimated shelf life exceeding one month of use at 25°C and at least one year of storage at 5°C
3	More than approximately 80% of initial formoterol remains after one month of use at 25°C and one year of storage at 5°C

Claim 3 is more concrete than claim 2 because it identifies a retained active-ingredient percentage. Claim 2 refers to an “estimated shelf-life,” which may require interpretation of the patent specification, analytical method and stability protocol.

The temperature and time conditions produce a two-stage stability profile:

Storage at 5°C for at least one year.
Usage exposure at 25°C for at least one month.

The claims appear directed to a formulation that remains chemically stable both during refrigerated storage and after transfer into ordinary-use conditions. A formulation that is stable only under refrigeration may not satisfy the full dependent-claim limitations.

The claim text supplied does not specify:

The degradation products included in the assay.
Whether the 80% threshold concerns total formoterol, a specific stereoisomer or active form.
The analytical method.
Whether stability is measured in unopened containers, opened containers or a nebulizer reservoir.
The permitted level of oxidation, hydrolysis or other degradation.

Those issues would materially affect infringement and validity analysis.

What formulations are protected by the buffer claims?

Claims 10 through 18 cover aqueous compositions containing a buffer, with narrower protection for citrate and defined concentration ranges.

Claim	Formulation limitation
10	The fluid comprises a buffer
11	Broad list of buffer systems
12	Citric acid/phosphate, acetate, citrate or phosphate buffer
13	Citrate buffer
14	Citrate buffer at approximately 0.01 to 150 mM
15	Citrate buffer at approximately 1 to 50 mM
16	Citrate buffer at approximately 1 to 20 mM
17	Citrate buffer at approximately 20 mM
18	Citrate buffer at approximately 5 mM

Claim 11 contains an extensive list of conventional and Good’s buffers, including MES, PIPES, MOPS, TES, HEPES, BICINE, TAPS and related systems. The list reaches beyond the narrower citrate and phosphate formulations in claims 12 through 18.

Claims 13 to 18 create a nested concentration structure. A formulation containing citrate buffer at approximately 5 mM could potentially fall within claim 13, claim 14, claim 15, claim 16 and claim 18, depending on the interpretation of overlapping “about” ranges.

The buffer claims are narrower and may be more vulnerable to design-around strategies. A manufacturer could consider:

An unbuffered formulation.
A buffer outside the listed systems.
A citrate concentration outside the claimed ranges.
A different pH-control system.
A formulation relying on a salt or excipient without a conventional buffer function.

Whether a particular excipient is legally a “buffer” would depend on its formulation role, concentration, pKa, pH-control behavior and the patent specification.

What tonicity agents are covered?

Claims 7 through 9 add tonicity-adjusting agents. Claim 8 lists a large group of possible agents, while claim 9 specifically identifies sodium chloride.

Examples in claim 8 include:

Sodium chloride
Dextrose
Glycerin
Mannitol
Sorbitol
Sucrose
Propylene glycol
Polyethylene glycol
Potassium chloride
Magnesium salts
Calcium salts
Citrate, phosphate and sulfate salts

Claim 9 is commercially important because sodium chloride is a common tonicity agent in inhalation solutions. A nebulized product containing formoterol, water, sodium chloride and a claimed concentration may implicate claims 1, 7 and 9 if the other limitations are met.

The patent does not appear, from the supplied claims, to require a particular osmolality. Claim 7 requires a tonicity-adjusting agent, not merely an excipient that happens to affect ionic strength.

What does the ionic-strength limitation cover?

Claims 19 and 20 narrow claim 8 by specifying ionic strength:

Claim	Ionic-strength range
19	Approximately 0 to approximately 0.4
20	Approximately 0.05 to approximately 0.16

Claim 20 is a narrower subset of claim 19. These claims may be relevant to isotonic or near-isotonic nebulizer formulations containing sodium chloride or another electrolyte.

Ionic strength is ordinarily calculated from the concentrations and charges of dissolved ionic species. The analysis may require accounting for:

Formoterol salt counterions.
Buffer components.
Sodium chloride.
pH-dependent ionization.
Multivalent ions.
Dilution before administration.

A formulation may satisfy the ionic-strength range even when sodium chloride is absent, provided the total ionic environment falls within the claimed interval and the composition also contains a qualifying tonicity agent.

Does claim 4 cover nebulization?

Claim 4 recites the composition of claim 1 “that has been nebulized.” This is a narrower claim with an unusual temporal limitation. It may require the claimed composition to have undergone nebulization rather than merely being suitable for nebulization.

The claim could raise several construction issues:

Whether the composition must be analyzed before or after aerosolization.
Whether loading the formulation into a nebulizer is sufficient.
Whether “has been nebulized” describes a product condition or a method of use.
Whether aerosolization changes concentration, pH or composition.
Whether a product sold in a vial before nebulization falls within the claim.

Claim 4 is less likely to be the primary enforcement claim against a pre-nebulization product because claim 1 is broader and does not require nebulization. It could still be relevant to use-based infringement theories involving administration of the formulation through a nebulizer.

How strong is the patent estate based on the supplied claims?

The apparent strength is mixed.

Strengths

The patent has several features that make claim 1 commercially relevant:

Broad coverage of formoterol derivatives.
A wide concentration range.
Express inclusion of water.
Coverage of stable formulations rather than only a specific excipient combination.
Dependent claims directed to common nebulizer formulation components.
Potential applicability to both free-base and salt formulations.

The broad derivative language limits chemical-form design-arounds. The water limitation, however, confines the claims to aqueous systems.

Vulnerabilities

The claims also present potential validity and enforcement issues:

“About” may create boundary uncertainty.
“Stable during long-term storage” may be indefinite if the specification does not define the test.
The concentration range is broad and could face written-description or enablement scrutiny depending on the examples.
Formoterol aqueous solutions may have substantial prior-art exposure.
Stability of a known active ingredient in water may be challenged as obvious if the prior art disclosed similar concentrations, buffers or storage conditions.
Claim 4 may be vulnerable to construction problems caused by the phrase “has been nebulized.”
The long list of buffers and tonicity agents may be attacked if the specification does not support the full breadth of the recited genus.

The strongest commercial claims may be those that combine a specific product concentration with a specific formulation component and measurable stability performance. The broadest claim is potentially the most valuable but also the most exposed to prior-art and enablement challenges.

When does US Patent 8,623,922 lose exclusivity?

A reliable expiration date cannot be determined from the claim text alone. Patent-term calculation requires the patent’s priority chain, filing dates, continuity data, terminal disclaimers, patent-term adjustment and any patent-term extension.

The relevant statutory framework is:

Utility patents generally expire 20 years from the earliest effective nonprovisional filing date, subject to applicable exceptions. 35 U.S.C. § 154.
Patent-term adjustment may extend the term for certain USPTO delays.
Patent-term extension under 35 U.S.C. § 156 may apply to qualifying regulatory delays.
A terminal disclaimer may shorten the effective term.
Regulatory exclusivity is separate from patent expiration.

The supplied claims do not establish the expiration date, patent-term adjustment, terminal disclaimer status or any patent-term extension. Accordingly, a definitive loss-of-exclusivity date is not supported by the supplied information.

What is the FDA and Orange Book status?

The claim text does not establish whether US Patent 8,623,922 is listed in the FDA Orange Book, whether it is listed against a specific formoterol reference product, or whether it has been delisted.

Orange Book relevance depends on several factors:

Issue	Relevance
Listed drug	Determines whether an ANDA applicant must address the patent
Patent type	Composition, formulation and method-of-use patents may be listed if statutory criteria are met
Approved product	The patent must claim the drug, formulation or approved use in the required manner
Certification	An ANDA applicant may file Paragraph I, II, III or IV certification
Notice	A Paragraph IV certification can trigger notice and litigation
Litigation	Timely litigation may create a 30-month stay under applicable FDA rules

Formoterol inhalation products may also involve product-specific labeling, device and combination-product issues. A patent covering an aqueous formulation does not automatically block every formoterol product or every inhalation device.

Are Paragraph IV challenges or generic launch risks established?

The supplied material does not identify any ANDA, Paragraph IV notice, district-court action, settlement or authorized generic arrangement connected with US 8,623,922.

Generic entry risk would depend on the challenger’s proposed product and certification strategy. The principal design-around routes would include:

Using a concentration outside the claimed range.
Using a nonaqueous formulation.
Omitting a listed buffer or tonicity agent.
Using a different active ingredient, such as arformoterol, if the claim does not cover it.
Challenging the stability limitation.
Challenging validity based on anticipation, obviousness, written description or enablement.
Arguing that the proposed product is outside the claim because its labeled concentration is not a free-base-equivalent concentration within the range.

A generic manufacturer could still face other patents, regulatory exclusivity, device-related rights or trade-secret barriers even if it defeats this patent.

How does this patent compare with other formoterol patent categories?

Formoterol intellectual property generally falls into several categories.

Patent category	Typical subject matter	Relevance to US 8,623,922
Active-ingredient patents	Formoterol molecule, stereochemistry or salts	Mostly separate from this formulation patent
Solid-form patents	Crystalline salts, polymorphs and hydrates	Potentially relevant to the selected formoterol derivative
Formulation patents	Aqueous concentration, pH, buffer, tonicity and stability	Directly aligned with this patent
Device patents	Nebulizers, inhalers and aerosol generators	Separate device-layer risk
Method-of-use patents	COPD, asthma, dosing or treatment regimens	May create additional Orange Book barriers
Manufacturing patents	Synthesis, purification and salt formation	Could restrict supply without blocking the finished product
Combination patents	Formoterol with corticosteroids or anticholinergics	Separate combination-product exposure

The patent is most relevant to ready-to-use aqueous nebulizer solutions. It is less directly relevant to dry-powder inhalers, metered-dose inhalers using propellant systems and products containing only arformoterol.

What geographic coverage does the patent provide?

US Patent 8,623,922 provides rights only in the United States. It does not establish protection in Canada, Europe, Japan, China or other jurisdictions.

International protection would require separate national or regional patent rights arising from the same priority family. The supplied claims do not identify corresponding foreign application or grant numbers, national phases, expiration dates or opposition outcomes.

A company commercializing formoterol inhalation products therefore needs separate freedom-to-operate analyses for:

United States
European Patent Convention states
Canada
Japan
China
Australia
Brazil
Other target markets

A US patent can affect US manufacture, importation, sale and use. It does not independently restrict sales in other countries.

Do licensing deals, litigation or settlements affect the patent?

No licensing agreement, litigation proceeding or settlement is identified in the supplied information. Those matters cannot be inferred from the claims.

A complete commercial assessment would distinguish among:

Patent ownership and assignment.
Exclusive or nonexclusive licenses.
Sublicenses to product marketers.
ANDA litigation.
Consent judgments.
Covenants not to sue.
Launch-at-risk arrangements.
Authorized generic agreements.
Settlement dates and permitted entry dates.

Without those records, the patent’s legal and commercial status should be analyzed from the claim set rather than treated as a confirmed barrier to market entry.

What generic launch scenarios exist?

Three principal scenarios follow from the claim structure.

Literal infringement avoidance

A generic product could be designed outside one or more required limitations, such as water, concentration, buffer, tonicity agent or ionic strength. This route is strongest when the alternative formulation preserves product performance without relying on the claimed stability architecture.

Paragraph IV validity challenge

A challenger could argue that the claimed aqueous formoterol formulation was anticipated or obvious. The broad concentration range and extensive excipient lists would be central to the analysis. Stability data would likely determine whether the claims provide a meaningful technical distinction over earlier formulations.

Paragraph III or delayed entry

If the patent remains listed and valid, a generic applicant could certify that it will not market until patent expiration. The commercial attractiveness of delayed entry would depend on the product’s market size, competing patents and expected launch timing.

Key Takeaways

US 8,623,922 is a formulation patent directed to stable aqueous formoterol compositions.
Claim 1 covers approximately 0.08 to 128 micrograms/mL of formoterol free base in a water-containing pharmaceutical fluid.
The derivative language reaches salts, solvates, hydrates, esters, prodrugs and related forms.
Dependent claims cover nebulization, polar and protic solvents, tonicity agents, sodium chloride, broad buffer systems, citrate buffers and defined ionic-strength ranges.
Claims 2 and 3 require long-term refrigerated stability and one-month use stability at 25°C.
The patent is most relevant to ready-to-use nebulized formoterol solutions.
The supplied information does not establish expiration, Orange Book listing, Paragraph IV activity, litigation, licensing, settlements or foreign-family status.
The main generic design-around opportunities involve concentration, vehicle, buffer, tonicity system and stability performance.
Patent strength will depend heavily on the specification’s support for the broad concentration, derivative, stability and excipient language.

FAQs

Does US 8,623,922 cover formoterol fumarate?

Potentially. Claim 1 expressly covers pharmaceutically acceptable salts and requires concentration to be assessed as formoterol free base. Formoterol fumarate may therefore fall within the claim if the aqueous formulation, stability and concentration limitations are satisfied.

Does the patent cover arformoterol?

The supplied claims recite “formoterol” and derivatives of formoterol. They do not expressly recite arformoterol. Coverage would depend on the patent’s specification, claim construction and whether arformoterol is legally treated as the claimed form or derivative.

Does a formulation need to contain sodium chloride to infringe?

No. Sodium chloride is a dependent-claim limitation. Claim 1 does not require sodium chloride, and claim 7 covers a broader class of tonicity-adjusting agents.

Can a product avoid the patent by using a citrate concentration above 20 mM?

Not necessarily. Claims 14 and 15 extend to approximately 150 mM and 50 mM, respectively. A product above 20 mM could remain within broader citrate-buffer claims, depending on the applicable “about” range and the remaining limitations.

Does patent protection prevent all generic formoterol inhalation products?

No. The claims are limited to specified compositions and related limitations. A generic product outside the aqueous vehicle, concentration, stability or dependent formulation limitations may not infringe this patent, although other patents or regulatory exclusivities could still affect entry.

References

United States Patent and Trademark Office. (n.d.). 35 U.S.C. § 154: Contents and term of patent; provisional rights.
United States Patent and Trademark Office. (n.d.). 35 U.S.C. § 156: Extension of patent term.
United States Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations.
United States Food and Drug Administration. (n.d.). Abbreviated new drug application submissions: Refuse-to-receive standards.

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: 8,623,922

Summary for Patent: 8,623,922