United States Patent 5,873,360: Scope, Claims, Expiration and Inhalation-Pack Patent Landscape

U.S. Patent No. 5,873,360 protects a flexible, elongate blister strip containing inhalable powder and formed from a recessed base sheet covered by a peelable lid sheet. The patent is directed to the medicament pack, not to a particular active ingredient, inhaler architecture, powder formulation, or therapeutic indication.

The patent was granted on February 23, 1999, to Glaxo Group Limited under the title "Medicament pack." Its enforceable U.S. term has expired. The patent therefore has no current blocking effect against generic manufacturers, inhaler developers, or contract packaging companies in the United States. Its claims remain relevant as prior art and as a model for analyzing later inhaler-pack patents. (U.S. Patent No. 5,873,360, 1999)

What does U.S. Patent 5,873,360 protect?

The patent protects a unit-dose powder inhalation pack having six central structural characteristics:

An elongate strip.
A base sheet.
Multiple spaced recesses in the base sheet.
A lid sheet sealed to the base sheet.
A hermetic but peelable seal.
Inhalable powdered medicament inside the resulting containers.

The claimed structure is consistent with a multi-dose blister strip that can be indexed through an inhalation device. The patent does not require a specific blister material, powder chemistry, inhaler brand, dosing schedule, or mechanism for peeling the lid.

The principal claim is claim 1. Claims 2 through 6 add winding, leading-end, attachment, seal-width, and peel-direction limitations.

Claim 1: core product claim

Claim 1 requires the following claim elements:

Element	Scope
Medicament pack	The claimed article is a pack containing medicament
Use in an inhalation device	The pack must be configured for inhalation-device use
Elongate strip	The pack must have a lengthwise strip configuration
Base sheet	A sheet forms the lower structure
Plurality of recesses	The base sheet includes multiple spaced cavities
Lid sheet	A separate sheet covers the cavities
Hermetic seal	The seal must prevent passage of air or moisture to the relevant degree
Peelable seal	The lid must be removable by peeling rather than permanent destruction
Containers	The sealed recesses define multiple compartments
Powder	Each container includes inhalable medicament in powder form

The claim uses "comprising," making it open-ended. A pack may include additional layers, coatings, tabs, reinforcing components, indexing features, or other structures without necessarily falling outside claim 1.

The claim is narrow in physical architecture but broad in commercial application. It does not depend on a particular inhaled drug. A pack containing a corticosteroid, long-acting beta agonist, anticholinergic, antibiotic, or combination powder could satisfy the claim if the structural elements are present.

What products fall outside claim 1?

A product may avoid literal infringement if it lacks a required element, including:

A circular blister disk rather than an elongate strip.
A strip with permanently sealed rather than peelable cavities.
A dry-powder reservoir without individual recesses.
A capsule-based inhaler using separate hard capsules.
A liquid or aerosol formulation rather than inhalable powder.
A pack with cavities formed in a structure that is not a base sheet.
A pack in which the lid is removed by tearing, puncturing, or rupture rather than peeling.

The doctrine of equivalents could affect designs that make insubstantial changes to the claimed architecture. The principal risk would concern a product that performs substantially the same function in substantially the same way to achieve substantially the same result. That analysis would be fact-specific and would remain subject to prosecution-history estoppel.

How do claims 2 through 6 narrow the patent scope?

The dependent claims add optional configurations that were commercially important for roll-fed, indexed inhaler systems.

Claim	Added limitation	Practical significance
2	Strip is sufficiently flexible to be wound into a roll	Covers roll-form blister-strip storage and delivery
3	Leading portions of lid and base sheets are not sealed together	Creates handling or attachment regions at the strip ends
4	At least one leading end portion is constructed for attachment to winding means	Covers connection to a reel, spindle, hub, or take-up mechanism
5	Hermetic seal extends across the whole width	Strengthens the seal limitation and addresses edge-to-edge compartment protection
6	Lid peels longitudinally from a first end of the base sheet	Covers end-to-end opening of the strip rather than transverse or localized opening

What formulation and delivery systems are protected?

The patent protects packaging and delivery architecture, not the powder formulation itself.

It may cover a strip containing:

Micronized active pharmaceutical ingredient.
Carrier-based dry powder blends.
Single-drug powders.
Combination powders.
Unit doses separated into individual blister recesses.

It does not claim:

Particle-size distributions.
Lactose or other carrier chemistry.
Specific drug combinations.
Stabilizers or excipients.
Powder manufacturing processes.
Device airflow characteristics.
Aerosolization performance.
Patient dosing instructions.

A later product could therefore avoid this patent while still requiring separate freedom-to-operate analysis for powder formulation, device mechanics, dose metering, or manufacturing patents.

When did U.S. Patent 5,873,360 lose exclusivity?

The patent's enforceable U.S. term expired around February 2015, based on the patent's 1995 U.S. filing framework and the statutory term applicable to the application. The patent was granted in 1999, but the grant date did not determine the full term for a post-1995 application.

Event	Date
U.S. patent grant	February 23, 1999
Approximate end of standard U.S. patent term	February 2015
Current enforceability	Expired
Current Paragraph IV significance	None for this expired patent
Current Orange Book blocking effect	None identified from this patent

Patent term adjustment or other prosecution-specific adjustments can alter the exact terminal date. Public patent records classify the patent as expired. (USPTO, n.d.-a; U.S. Patent No. 5,873,360, 1999)

The expiration eliminates infringement exposure based solely on this patent. It does not eliminate exposure under later patents covering related blister-strip devices, sealing systems, inhaler mechanisms, or commercial drug products.

What is the Orange Book status of U.S. Patent 5,873,360?

U.S. Patent 5,873,360 is a packaging and device-related patent rather than a conventional active-ingredient, formulation, or method-of-use patent. Patents of this type are not automatically listed in the FDA Orange Book.

The Orange Book permits listing of patents that claim an approved drug substance, drug product, or approved method of using the drug. A stand-alone medicament-pack patent may not qualify unless its claims meet the FDA's listing requirements and are properly associated with an approved product. (FDA, 2024)

The practical consequences are:

It should not be treated as an Orange Book patent merely because it relates to an inhaled medicine.
It should not create a current Paragraph IV certification obligation if it is absent from the applicable Orange Book listing.
Its expiration independently removes any current U.S. enforcement value.
An applicant challenging a later-listed inhaler patent would need to analyze that later patent separately.

Does the patent create Paragraph IV or generic-launch risk?

No current Paragraph IV risk arises from U.S. Patent 5,873,360 itself because the patent has expired. A generic or authorized-generic manufacturer can use the claimed pack architecture in the United States without infringing this patent.

Generic-launch risk can still arise from other rights, including:

Later inhaler-device patents.
Drug-product patents listed in the Orange Book.
Method-of-use patents.
Manufacturing and filling patents.
Packaging patents with later expiration dates.
Regulatory exclusivity.
Trademark and trade-dress restrictions.
Product-specific device approval requirements.

For inhaled products, regulatory substitution is often more complex than for conventional oral solids. The applicant may need to demonstrate comparable dose delivery, emitted dose, aerodynamic particle-size distribution, device performance, and product quality. FDA approval requirements do not revive an expired patent, but they can delay commercial entry. (FDA, 2023)

Which companies and products are commercially relevant?

The patent is associated with the blister-strip inhalation-pack architecture developed for products such as Glaxo's multi-dose dry-powder inhaler platforms. Its commercial relevance is strongest in devices that store multiple unit doses in a continuous strip and expose each dose through sequential peeling or indexing.

Relevant product categories include:

Product category	Relevance to Patent 5,873,360
Multi-dose dry-powder inhalers	High, if they use a peelable elongate blister strip
Single-dose capsule inhalers	Generally outside claim 1
Circular blister disks	Potentially outside the elongate-strip limitation
Reservoir inhalers	Generally outside the individual-recess requirement
Metered-dose inhalers	Generally outside the powder blister-strip architecture
Unit-dose foil pouches	Possible overlap only if they satisfy the claimed sheet-and-recess structure

GlaxoSmithKline's Diskus-related commercial platform is the closest commercial reference point, although a specific marketed device must be analyzed against the claim language and its own later patent portfolio. The patent alone does not establish that every Diskus product or every later inhaler version falls within every claim.

What patent families and related rights should be reviewed?

The relevant landscape is broader than U.S. Patent 5,873,360. A complete diligence review should separate the following patent families.

Blister-strip and pack patents

These cover:

Formed recesses and blister geometry.
Foil or polymer laminate structures.
Peelable heat-seal systems.
Moisture-barrier layers.
Longitudinal strip opening.
Roll storage and winding.
End-tab attachment.
Dose indexing and cavity registration.

Inhaler-device patents

These cover:

Strip advancement.
Peeling mechanisms.
Winding and take-up reels.
Dose presentation.
Mouthpiece and airflow paths.
Piercing, cutting, or separating blister cavities.
Dose counters.
Priming and actuation systems.

Formulation patents

These may cover:

Specific active ingredients.
Combination therapies.
Carrier particles.
Lactose grades.
Stabilizers.
Particle engineering.
Moisture control.
Cohesive-adhesive powder blends.

Method-of-use patents

These may claim treatment of:

Asthma.
Chronic obstructive pulmonary disease.
Allergic respiratory disease.
Exercise-induced bronchoconstriction.
Acute or maintenance respiratory conditions.

The expired pack patent cannot be used to establish freedom to operate for these adjacent rights.

How strong is the patent estate today?

The current enforceability of the estate represented by U.S. Patent 5,873,360 is effectively zero in the United States because the patent has expired. Its historical claim strength was higher for products using the specific combination of:

An elongate multi-cavity strip.
A peelable hermetic lid.
Powder-filled containers.
Longitudinal opening.
Optional roll winding.

Claim 1 was the commercially important claim because it did not require a roll, an unsealed leading end, a winding attachment, full-width sealing, or a specified peel direction. Claims 2 through 6 were narrower fallback positions.

Risk category	Current assessment
Direct infringement of Patent 5,873,360	No current U.S. patent-term risk
Historical infringement risk	Material for qualifying blister-strip products
Formulation infringement	Not addressed by this patent
Device-mechanism infringement	Not addressed except indirectly through pack structure
Orange Book litigation	Unlikely based on this patent alone
Paragraph IV litigation	None based on this expired patent
Biosimilar risk	Not applicable
Manufacturing barrier	No current barrier from this patent
Geographic risk	U.S. rights expired; foreign family members require country-by-country review
Prior-art value	High for later blister-strip and inhaler-pack claims

What geographic coverage remains relevant?

Patent expiration must be assessed by country. U.S. expiration does not establish that corresponding patents in Europe, Canada, Japan, Australia, or other jurisdictions expired on the same date.

The international landscape may include:

National counterparts.
European regional patents.
Continuations or divisionals.
Patent term extensions.
Supplementary protection certificates.
National prosecution differences.
Abandoned or lapsed family members.

For a current commercial launch, the relevant question is not whether the international family once existed, but whether an unexpired counterpart covers the proposed pack in each launch country. The U.S. patent itself provides no current U.S. exclusionary right.

Were there licensing deals or settlements tied to the patent?

No publicly established licensing deal or settlement can be attributed to U.S. Patent 5,873,360 from the patent record alone. Glaxo-related inhaler technology was commercialized through an integrated product and device portfolio, and individual packaging patents may have been included in broader confidential licenses or supply arrangements.

The absence of a public license record does not establish that no private agreement existed. It means the patent should not be treated as evidence of a disclosed compulsory license, generic settlement, or cross-license.

Because the patent is expired, any historical settlement involving it would have no continuing exclusionary effect unless it also covered separate unexpired patents, trademarks, confidential know-how, or contractual restrictions.

What generic launch scenarios exist?

A competitor could use a similar blister-strip concept in the United States without infringing this expired patent. The practical launch pathways include:

New dry-powder inhaler

A company can develop a new inhaler using a strip pack, provided it clears later device, formulation, and drug-product patents.

Generic version of an approved inhaled drug

The applicant would need to address FDA requirements for the drug-device combination and evaluate Orange Book-listed patents associated with the reference product.

Authorized generic

An authorized generic could use comparable packaging or a licensed device platform, subject to the relevant commercial agreement.

Contract-manufactured blister packs

A packaging supplier could manufacture similar packs, but later patents and confidential manufacturing know-how may remain relevant.

Key Takeaways

U.S. Patent 5,873,360 claims a multi-dose, elongate blister strip for inhalable powder.
Claim 1 is the broadest claim and requires a recessed base sheet, peelable hermetic lid, multiple containers, and powder medicament.
Claims 2 through 6 cover roll winding, unsealed leading ends, winding attachment, full-width sealing, and longitudinal peeling.
The patent does not claim a specific drug, formulation, inhaler airflow path, or therapeutic method.
The U.S. patent expired around February 2015 and has no current U.S. blocking effect.
It is not, based on its subject matter, a conventional Orange Book drug-substance or method-of-use patent.
Paragraph IV risk from this patent is no longer material.
Later blister-pack, inhaler-device, formulation, manufacturing, and method-of-use patents remain the relevant freedom-to-operate risks.
Foreign counterparts require separate country-level term and validity analysis.
The patent remains important prior art for later inhalation-pack patent prosecution and validity analysis.

FAQs

Can a company manufacture a similar inhaler blister strip in the United States?

Yes, U.S. Patent 5,873,360 is expired. The manufacturer must still evaluate later patents covering the inhaler, formulation, sealing materials, dose indexing, and manufacturing process.

Does the patent cover Advair, Serevent, or other specific drugs?

No. The claims are product-architecture claims. They require inhalable powder in sealed recesses but do not identify a particular active ingredient.

Does claim 1 cover a circular blister disk?

Probably not on its face because claim 1 requires an "elongate strip." A circular disk may raise a doctrine-of-equivalents issue only if the facts support equivalence.

Is a foil pouch covered by the patent?

Not necessarily. A pouch must satisfy the claim's base-sheet, spaced-recess, lid-sheet, hermetic-peelable-seal, and multiple-container limitations. A flat pouch lacking formed recesses may fall outside claim 1.

Can this patent block a biosimilar or generic inhaled biologic?

No. Biosimilar status is not relevant to this expired packaging patent. Any current barrier would arise from separate drug, device, formulation, regulatory, or manufacturing rights.

References

Food and Drug Administration. (2023). Product-specific guidances for generic drug development. U.S. Department of Health and Human Services.
Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. U.S. Department of Health and Human Services.
United States Patent and Trademark Office. (n.d.-a). Patent term adjustment and patent term calculation. U.S. Department of Commerce.
U.S. Patent No. 5,873,360. (1999). Medicament pack. Issued February 23, 1999. Assigned to Glaxo Group Limited.

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
United Kingdom	90 04781	Mar 02, 1990

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
African Regional IP Organization (ARIPO)	310	⤷ Start Trial
African Regional IP Organization (ARIPO)	9100321	⤷ Start Trial
Austria	401007	⤷ Start Trial
Austria	A43791	⤷ Start Trial
Australia	5926794	⤷ Start Trial
Australia	645056	⤷ Start Trial
Australia	675825	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 5,873,360

Summary for Patent: 5,873,360