US Patent 7,632,517: Zolpidem Oral Spray Claims, Patent Scope and Market Landscape

US Patent 7,632,517 protects a method of treating insomnia by spraying a liquid zolpidem formulation onto the oral mucosa to achieve transmucosal delivery. Its core limitations are the zolpidem concentration, polar-solvent concentration, presence of water, oral-mucosal administration, and systemic delivery sufficient to treat insomnia. The patent’s ordinary US term was calculated from the March 8, 2004 nonprovisional filing date and therefore reached its base expiration in March 2024, subject to any patent-term adjustment or extension recorded by the USPTO. The claims do not provide a continuing enforceable barrier after expiration.

What does US Patent 7,632,517 protect?

The patent protects a treatment method rather than a composition standing alone. Claim 1 requires all of the following:

A human patient with insomnia.
An oral spray composition containing zolpidem or a pharmaceutically acceptable salt.
Zolpidem concentration between 2.5% and 20% by weight.
A polar solvent concentration between 15% and 60% by weight.
Water in the composition.
Spraying onto the oral mucosa.
Transmucosal absorption into the systemic circulation.
Delivery of an amount sufficient to treat insomnia.

A product that contains zolpidem in the claimed concentration range but is swallowed as a conventional tablet does not satisfy the administration limitation. Conversely, an oral spray could raise infringement issues even if its commercial labeling does not use the phrase “transmucosal,” if its intended or actual use involves absorption through the oral mucosa.

The patent is associated with the zolpidem oral-spray product Zolpimist, an FDA-approved prescription spray containing zolpidem tartrate. The FDA approved Zolpimist under NDA 022139 in 2008. [1][2]

How do the 21 claims differ?

Claim 1 is the broadest independent claim supplied. Claims 2 through 21 progressively narrow the formulation or administration requirements.

Claim group	Principal limitation	Commercial significance
Claim 1	Zolpidem, water, polar solvent, oral-mucosal spray and systemic treatment	Core method claim
Claim 2	Taste mask and/or flavoring at 0.1% to 10%	Covers palatability systems
Claims 3-4	Zolpidem at 2.5%-15% or 2.5%-10%	Narrows active concentration
Claim 5	Zolpidem salt is zolpidem tartrate	Aligns with Zolpimist-type product
Claims 6-7	Polar solvent at 25%-50% or 30%-45%	Narrows solvent loading
Claim 8	Defined solvent classes	Limits the solvent identity
Claims 9-11	Polyethylene glycol, ethanol or propylene glycol	Covers named commercial formulation options
Claim 12	Mint oils, citrus oils, fruit flavors, sweeteners or mixtures	Covers specific flavor systems
Claim 13	Predetermined spray amount	Targets metered-dose delivery
Claim 14	Propellant-free composition	Covers pump-spray systems
Claim 15	Buffer	Adds pH-control limitation
Claims 16-21	Zolpidem tartrate plus propylene glycol, with concentration, buffer, flavor and propellant-free limitations	Narrowest commercial-style embodiments

The most commercially important dependent claims are claims 16 through 21. They describe a formulation containing zolpidem tartrate and propylene glycol, with narrower concentration ranges and optional buffer, flavor and propellant-free limitations.

What is the scope of the core method claim?

Claim 1 is broad in formulation architecture but narrow in delivery route. It does not require a specific pump, nozzle, spray volume, pH, dose per actuation, container, preservative, or flavor. It also does not expressly require that the product be marketed under a particular brand.

The claim has five principal scope boundaries:

Active ingredient

The claim covers zolpidem and pharmaceutically acceptable salts. Claim 5 specifically identifies zolpidem tartrate. A formulation using a different salt could fall within claim 1 if it otherwise satisfies the claim, even though it would not fall within claim 5.

Concentration

The formulation must contain between 2.5% and 20% zolpidem or salt by total composition weight. Claims 3 and 4 create narrower ranges but do not expand claim 1.

A formulation below 2.5% or above 20% is outside the literal concentration range of claim 1. The treatment dose delivered per spray is separate from the formulation concentration. Claim 1 does not specify a particular milligram dose.

Polar solvent

The solvent must be present at 15% to 60% by weight. Claim 8 identifies several permissible classes, including polyethylene glycols with molecular weights of 400 to 1,000, C2-C8 mono- and poly-alcohols, and C7-C18 linear or branched alcohols.

Claims 9, 10 and 11 specifically cover polyethylene glycol, ethanol and propylene glycol. The narrower dependent claims may be avoided by using another solvent, but a different solvent could still fall within claim 1 if it qualifies as a polar solvent and satisfies the concentration requirement.

Water

Water is a required component. A substantially anhydrous spray would present a direct claim-scope issue under claim 1. The claim text does not specify a minimum water concentration.

Route and therapeutic result

The composition must be sprayed onto the oral mucosa and absorbed through that mucosa into systemic circulation in an amount sufficient to treat insomnia. This limitation distinguishes the patent from ordinary oral tablets, capsules, sublingual tablets, buccal films and non-systemic oral sprays.

What formulations are protected by US 7,632,517?

The clearest covered formulation is a propellant-free, metered oral spray containing:

zolpidem tartrate;
water;
propylene glycol;
an optional buffer;
an optional flavorant or taste-masking agent; and
zolpidem tartrate at 2.5% to 10% by weight.

Claims 16 through 21 establish a particularly specific formulation chain:

Claim	Required formulation features
16	Zolpidem tartrate and propylene glycol
17	Zolpidem tartrate at 2.5%-10%
18	Propylene glycol at 20%-45%
19	Buffer
20	Flavorant or taste masking agent
21	Propellant-free composition

The claims do not require a particular flavor, although claim 12 identifies peppermint oil, spearmint oil, citrus oil, fruit flavors and sweeteners. They also do not require a specific device, provided the composition is sprayed onto oral mucosa and the amount is predetermined where claim 13 is asserted.

How strong are the claims from an infringement perspective?

The claim set has moderate historical enforcement value because it combines measurable formulation limitations with a defined administration route. The concentration ranges and named ingredients make laboratory testing and product comparison practical.

Its principal strengths were:

coverage of both composition and use through a method-of-treatment framework;
explicit coverage of zolpidem tartrate;
broad coverage of several polar solvents;
coverage of propellant-free pump systems;
no requirement for a specific brand, device manufacturer or spray mechanism;
dependent claims directed to a commercially plausible propylene-glycol formulation.

Its principal vulnerabilities were:

the broad terms “polar solvent,” “water” and “sufficient to treat”;
potential enablement and written-description disputes across the full solvent and concentration ranges;
the need to prove oral-mucosal absorption rather than simple oral deposition or swallowing;
possible design-around opportunities using concentrations outside the claimed ranges;
the method-claim requirement to establish the relevant use or inducement by the accused product.

A formulation manufacturer would normally assess infringement against claim 1 first, then claims 5, 11 and 16-21 if the product uses zolpidem tartrate and propylene glycol.

When did US Patent 7,632,517 lose exclusivity?

The base US patent term ran 20 years from the March 8, 2004 nonprovisional filing date. On that calculation, the term ended in March 2024, unless the USPTO recorded patent-term adjustment, patent-term extension or another applicable term modification. [3]

The patent’s 2009 issue date did not establish the expiration date. For modern US patents, the relevant baseline is generally the earliest effective nonprovisional filing date in the application chain, not the grant date. A continuation or divisional generally does not create a new 20-year term.

Any six-month pediatric exclusivity would have been a regulatory marketing-exclusivity period associated with an FDA product and would not independently convert an expired patent into a live patent right. FDA regulatory exclusivity and patent term must be analyzed separately. [1][4]

What is the Orange Book status of the zolpidem oral spray patent?

The FDA Orange Book is the relevant source for determining whether a patent was listed against an approved drug product and whether an applicant had to address that listing in an abbreviated new drug application. Zolpimist was approved under NDA 022139, and US 7,632,517 was associated with the product’s oral-spray technology. [1][2]

An Orange Book listing did not itself extend the patent term. After patent expiration, the listing could remain historically relevant to earlier ANDA certifications, but it would not support a current patent-infringement action unless another enforceable right applied.

The key distinction is:

Issue	Effect
Orange Book listing	Identifies a patent FDA considered relevant to the approved product
Paragraph IV certification	Allegation that a listed patent is invalid, unenforceable or not infringed
Patent expiration	Removes the ordinary infringement barrier after the expiration date
FDA exclusivity	Can delay approval independently of patent rights
Patent-term extension	Can extend a patent only if formally granted and recorded

Were there Paragraph IV challenges or patent litigation?

A Paragraph IV certification is an ANDA applicant’s assertion that a listed patent is invalid, unenforceable or will not be infringed. The certification can trigger Hatch-Waxman litigation and, in qualifying circumstances, a 30-month FDA approval stay. [4]

The supplied claim text does not establish that a Paragraph IV notice, ANDA litigation case, settlement agreement or court judgment was filed. Those events are established through FDA ANDA records, district-court dockets and settlement disclosures, not through the patent claims themselves.

For business analysis, the relevant current conclusion is that a Paragraph IV challenge directed solely to US 7,632,517 would have limited present commercial value after the patent’s ordinary March 2024 expiration. Earlier challenges could have affected launch timing, but they would not create a current exclusionary period after expiration.

What other patent barriers could affect a zolpidem oral-spray generic?

A generic or follow-on sponsor would need to separate several possible rights:

Formulation patents

These may cover:

solvent systems;
taste-masking systems;
pH buffers;
preservatives;
viscosity modifiers;
pump compatibility;
container-closure systems; and
dose-metering mechanisms.

The 7,632,517 claims are formulation-linked method claims, but a later patent could protect a narrower commercial formulation or delivery device.

Method-of-use patents

A later patent could claim:

a specific zolpidem dose;
rapid-onset treatment;
administration immediately before bedtime;
treatment of sleep-maintenance or sleep-onset insomnia;
reduced next-morning impairment; or
a particular patient population.

Such claims would require separate validity, enforceability and Orange Book analysis.

Manufacturing and device rights

A competing spray may avoid the patent’s formulation ranges but still encounter rights covering:

pump calibration;
spray plume characteristics;
filling processes;
moisture control;
preservative systems;
dose uniformity; or
container materials.

These rights are often more relevant to commercial launch than the expired core patent.

How does the patent compare with conventional zolpidem products?

Attribute	Zolpidem tablet or capsule	Zolpidem oral spray under the claimed architecture
Administration	Swallowed	Sprayed onto oral mucosa
Delivery objective	Gastrointestinal absorption	Transmucosal systemic absorption
Water requirement	Product-specific	Required by claim 1
Polar solvent range	Not required by this patent	15%-60% under claim 1
Zolpidem concentration	Usually measured per dosage unit	2.5%-20% by weight
Propellant-free requirement	Not applicable	Covered by claim 14 and claim 21
Device requirement	Tablet/capsule	Spray mechanism, with predetermined amount in claim 13
Patent relevance	Conventional zolpidem patents and formulation rights	US 7,632,517 and related oral-spray rights

The patent therefore targets a delivery-system distinction rather than zolpidem’s underlying pharmacology.

What is the competitive and commercial exposure?

The principal commercial exposure was the market for branded or generic zolpidem oral sprays. The patent did not block conventional zolpidem tablets, orally disintegrating tablets or unrelated insomnia medicines.

Potential competing products would include:

conventional zolpidem tartrate tablets;
zolpidem extended-release tablets;
zolpidem sublingual products such as Intermezzo;
non-zolpidem hypnotics;
melatonin-receptor agonists;
orexin-receptor antagonists; and
compounded or extemporaneous oral sprays.

Because the patent expired on its ordinary term calculation in March 2024, its current revenue-protection value is limited. Any remaining commercial protection would need to come from a separate unexpired patent, FDA exclusivity, trademark rights, manufacturing know-how, device ownership, supply agreements or regulatory barriers.

Public FDA approval records identify the regulatory product, but they do not establish product-level revenue. Revenue exposure should therefore be assessed against current sales of the branded product and any successor product, not against the patent alone.

What licensing and settlement issues matter?

A license to US 7,632,517 would historically have been relevant to:

commercial manufacture of zolpidem oral spray;
distribution of Zolpimist or an authorized equivalent;
use of the claimed propylene-glycol formulation;
pump-device integration; and
territorial rights outside the United States.

After patent expiration, a license limited solely to this patent generally loses exclusionary value in the United States, although royalty, confidentiality, know-how, trademark and supply provisions can survive according to their contract terms.

No settlement terms should be inferred from the claim set. A Hatch-Waxman settlement would need to be evaluated for entry date, license date, restrictions on authorized generic supply, payment provisions, and Federal Trade Commission reporting implications.

What is the geographic coverage?

US Patent 7,632,517 covers the United States only. It does not provide rights in Canada, Europe, Japan, China or other jurisdictions.

International protection would depend on separate national or regional family members. The US claims cannot be used to block manufacture, sale or use outside the United States, although importation into the US can create domestic patent issues during the enforceable term.

Key Takeaways

US 7,632,517 is a method patent covering transmucosal administration of a defined zolpidem oral spray.
Claim 1 requires zolpidem, water, a polar solvent, specified concentration ranges and oral-mucosal systemic delivery.
Claims 16-21 focus on zolpidem tartrate with propylene glycol, buffer, flavoring and a propellant-free formulation.
The patent does not cover conventional swallowed zolpidem products merely because they contain the same active ingredient.
The ordinary US patent term ran from the March 8, 2004 filing date and reached expiration in March 2024, subject to the USPTO’s recorded term adjustment or extension data.
A current generic launch assessment must focus on later patents, FDA exclusivity, device rights, manufacturing know-how and regulatory status.
Orange Book listing and Paragraph IV certification affect FDA approval procedure but do not extend an expired patent.
No litigation, settlement or licensing terms are established by the claim language alone.

FAQs

Can a generic zolpidem spray avoid US 7,632,517 by using ethanol instead of propylene glycol?

Not necessarily. Claim 10 expressly identifies ethanol, and claim 8 broadly covers C2-C8 alcohols. Ethanol would still need to satisfy the other claim 1 limitations, including water, the 2.5%-20% zolpidem range, the 15%-60% polar-solvent range and transmucosal administration.

Does a propellant-free pump automatically infringe the patent?

No. A propellant-free pump is relevant to claims 14 and 21, but infringement requires satisfaction of every limitation in the asserted claim. The product must also contain the required active, water and solvent ranges and be used for the claimed oral-mucosal treatment.

Does zolpidem tartrate at 2% fall within the claims?

It does not fall within the literal zolpidem concentration range of claim 1 or claims 3, 4 and 17, which begin at 2.5% by weight. A separate infringement analysis would be required for any doctrine-of-equivalents theory, but the patent’s express numerical lower limit is a substantial design-around boundary.

Does the patent cover an oral spray that is swallowed after spraying?

The claim requires spraying on the oral mucosa and transmucosal absorption into systemic circulation. A product designed only for swallowing would not satisfy the express delivery limitation, although actual labeling, instructions and pharmacokinetic evidence would be relevant to an inducement or product-use analysis.

Can FDA approve a generic after the patent expires without a Paragraph IV challenge?

Yes, assuming no other unexpired listed patent, regulatory exclusivity or applicable approval barrier remains. After expiration, an applicant would not need to maintain a Paragraph IV position against that expired patent as a continuing basis for launch protection.

References

U.S. Food and Drug Administration. (2008). Zolpimist (zolpidem tartrate) oral spray, NDA 022139 approval materials and prescribing information. FDA.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. FDA.
United States Patent and Trademark Office. (2009). U.S. Patent No. 7,632,517, Zolpidem oral spray. U.S. Department of Commerce.
U.S. Food and Drug Administration. (2023). Abbreviated new drug application approvals and patent certifications under the Hatch-Waxman Act. FDA.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Australia	2003262916	⤷ Start Trial
Australia	2003262917	⤷ Start Trial
Australia	2003270014	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 7,632,517

Summary for Patent: 7,632,517