Details for Patent: 4,524,769

Summary for Patent: 4,524,769

Title:	Dosage inhalator
Abstract:	A powder inhalator which is activated by the air flow generated at inhalation and which is intended for inhalation of solid pharmacologically active compound in micronized form, said inhalator comprising a nozzle 2, an air conduit 6, a dosing unit 10 comprising a storage chamber 5 for the active compound and dosing means 8, and a maneuvering unit 1, characterized in that the dosing unit 10 comprises a storage chamber 5 for the active compound, a perforated membrane 4, a holder 9 for the said perforated membrane, and dosing means 8 for introducing active compound into the perforations in the perforated membrane 4, whereby means are arranged for displacing the membrane 4 in relation to the dosing means 8, whereby in a first position solid active compound in micronized form is introduced into the perforations in part of the area of the membrane 4 and in a second position the said part of the membrane 4 is inserted in the air conduit 6 for the air to be inhaled.
Inventor(s):	Kjell I. L. Wetterlin
Assignee:	Draco AB
Application Number:	US06/389,213
Patent Claim Types: see list of patent claims	Compound; Delivery;

United States Patent 4,524,769: Scope, Claim Construction, Expiration, and Dry-Powder Inhaler Patent Landscape

U.S. Patent No. 4,524,769 covers a multidose dry-powder inhaler that uses a movable perforated membrane to meter micronized drug doses into an airflow conduit. The patent is directed primarily to the inhaler mechanism, not to terbutaline, budesonide, or any underlying pharmaceutical composition. It issued on June 25, 1985, and its ordinary 17-year patent term expired on June 25, 2002. The patent therefore does not create a current U.S. blocking right or a present Paragraph IV risk.

The strongest historical claims are independent claims 1 and 10. Claim 10 is broader in structural terms because it omits several components required by claim 1, including the storage chamber, nozzle, loading mechanism, and maneuvering mechanism. Claims 7 and 8 narrow claim 1 to inhalers containing terbutaline or budesonide.

What technology does U.S. Patent 4,524,769 protect?

The patent protects a dose-metering architecture for dry-powder inhalation. Its central element is a perforated membrane containing multiple preselected dose portions. Each portion holds a reproducible amount of micronized drug powder. The membrane moves successive portions into an air conduit, where the powder is entrained in gas and delivered to the patient.

The claims require a combination of the following technical concepts:

Technical element	Claim significance
Micronized solid drug	The compound must be in dry powder form with particle size below 5 micrometers
Unit-dose metering	Each preselected membrane portion holds a reproducible dose
Perforated membrane	The dose is retained in membrane perforations rather than in a conventional blister or capsule
Movable dose carrier	The membrane moves successive dose portions into the gas conduit
Gas-powered dispersion	Air or another gas carries the powder to the patient
Dose loading	Powder is introduced into perforations while the relevant membrane portion is outside the conduit
Low dose quantity	The broad claims require less than 50 mg; dependent claims specify approximately 0.1 to 5 mg
Optional drug identity	Claims 7 and 8 identify terbutaline and budesonide

The inventive center is the integration of powder loading and dose dispensing in a moving, perforated dose carrier. A product that merely uses a micronized powder in a dry-powder inhaler would not necessarily fall within the claims.

How should independent claim 1 be construed?

Claim 1 is an apparatus combination claim. An accused product must contain each required limitation or its legally recognized equivalent.

Claim 1 limitation analysis

Claim 1 limitation	Scope and practical effect
Dosage inhalator	The claim is limited to an inhalation delivery device
Micronized active compound	The device must dispense a pharmacologically active compound in powder form
Particle size below 5 micrometers	The claimed powder is respirable micronized material
Nozzle and connected conduit	The device must have an airflow path terminating in a nozzle
Storage chamber adjacent to the conduit	Powder is stored within the device before dosing
Perforated membrane	The dose carrier has multiple perforated portions
Reproducible unit dose	Each portion must hold and dispense a controlled amount
Less than 50 mg	The broad dose ceiling applies to each unit dose
Membrane movement between chamber and conduit	One dose portion is dispensed while another portion is loaded
Dose loading means	The chamber loads powder into membrane perforations
Maneuvering means	The membrane is displaced through multiple dispensing positions

The claim is narrower than a generic “dry-powder inhaler” claim. It requires a specific relationship between the storage chamber, perforated membrane, loading location, and conduit. A blister-strip inhaler, capsule-based inhaler, reservoir inhaler, or device using prefilled individual cavities may avoid literal infringement if it lacks the claimed membrane-loading arrangement.

The phrase “reproducible unit dose” is commercially important. Random powder entrainment from a bulk reservoir is not necessarily enough. The claim focuses on a defined dose portion that is loaded into perforations and subsequently positioned in the airflow.

How broad is independent claim 10 compared with claim 1?

Claim 10 is the patent’s broadest independent apparatus claim based on the supplied claims. It requires:

1. A gas conduit;
2. A movable membrane;
3. Multiple preselected perforated portions;
4. Each portion adapted to hold and dispense less than 50 mg of micronized powder;
5. Successive positioning of the portions within the conduit; and
6. Movement of used portions to an external position where they can receive additional powder.

Unlike claim 1, claim 10 does not expressly require:

• A nozzle;
• A storage chamber;
• A separate dose-loading means;
• A scraper;
• A spring;
• A rotating membrane;
• A specified drug;
• A particular dose range of 0.1 to 5 mg.

Claim 10 could therefore reach a wider range of devices, including devices in which the membrane itself moves between an external loading location and an internal dispensing position without the precise chamber and loading structure recited in claim 1.

The claim still requires a perforated membrane with repeatable dose portions. A device that uses sealed blisters, foil pockets, capsules, prefilled cartridges, or a conventional reservoir would present a stronger non-infringement position if no perforated membrane performs the claimed dose-storage function.

What do dependent claims 2 through 6 protect?

Claims 2 through 6 narrow the mechanical design.

Claim 2: rotating membrane

Claim 2 requires the perforated membrane to be mounted for rotation. This limitation is consistent with a rotating disk, wheel, or circular dose carrier. A linearly advancing strip or reciprocating plate would not literally satisfy the rotation limitation.

Claims 3 and 4: scraper and spring arrangements

Claim 3 requires:

• A scraper;
• A spring urging the scraper against the membrane; and
• Placement of the scraper and spring in the storage chamber.

Claim 4 uses a different spring relationship. The maneuvering means includes a spring that urges the rotating membrane against the scraper.

These claims protect powder-loading and excess-powder-removal mechanisms. The distinction between claims 3 and 4 lies in which component the spring biases. That distinction could matter in an infringement analysis involving a rotating dose disk and a doctor blade or scraper.

Claim 5: frustoconical perforations

Claim 5 requires each perforation to have a frustoconical shape, with the larger end closer to the nozzle. This geometry is intended to support powder release toward the airflow path.

A cylindrical hole, reverse-tapered hole, irregular cavity, or non-through pocket could avoid literal infringement of claim 5, although the broader claims would require separate analysis.

Claim 6: multiple holes per dose portion

Claim 6 requires each dose portion to contain multiple perforations of substantially the same size. Each perforation holds a share of the total dose.

This limitation is narrower than a single-cavity-per-dose design. It also supports the patent’s emphasis on dose reproducibility through multiple substantially uniform openings.

What do claims 7 through 12 add?

Claim	Added limitation
7	The active compound is terbutaline
8	The active compound is budesonide
9	The unit dose is approximately 0.1 to 5 mg
10	Separate broad inhaler architecture based on a movable perforated membrane
11	Claim 10 narrowed to approximately 0.1 to 5 mg per dose
12	Each dose portion has multiple substantially equal perforations

Claims 7 and 8 do not claim terbutaline or budesonide as chemical compounds. They claim an inhaler according to claim 1 that contains one of those compounds. The claims therefore depend on the apparatus limitations of claim 1.

A budesonide formulation in a conventional dry-powder inhaler would not infringe claim 8 merely because it contains budesonide. The accused device would also need the claimed perforated-membrane and dose-loading architecture.

What particle-size and dose limitations matter?

The patent contains two quantitative thresholds:

• Particle size below 5 micrometers;
• Unit dose below 50 mg.

Dependent claims 9 and 11 narrow the dose to approximately 0.1 to 5 mg.

These limitations separate the claimed architecture from larger-particle oral powders and from high-volume powder delivery systems. In practice, many inhaled corticosteroid and bronchodilator doses fall within the 0.1 to 5 mg range, but that fact alone does not establish infringement. The device architecture remains essential.

Particle size could become a technical dispute. The claims do not specify whether “particle size” means median aerodynamic diameter, mass median aerodynamic diameter, geometric diameter, or another measurement. For an infringement or validity analysis, the relevant specification, prosecution history, and accepted analytical method would be material. The supplied claims alone do not resolve that measurement issue.

When did U.S. Patent 4,524,769 lose exclusivity?

U.S. Patent No. 4,524,769 issued on June 25, 1985. Under the pre-Uruguay Round patent-term rule applicable to this patent, the ordinary term was 17 years from issuance. The resulting expiration date was June 25, 2002, absent an unusual terminal disclaimer or other record-specific adjustment. The patent is therefore expired and cannot support a new U.S. patent-infringement action for conduct occurring after expiration. (U.S. Patent No. 4,524,769, 1985; 35 U.S.C. § 154.)

Event	Date
U.S. patent issuance	June 25, 1985
Ordinary 17-year expiration	June 25, 2002
Current enforceability	Expired
Current Paragraph IV relevance	None for this patent
Current biosimilar relevance	None

The patent’s expiration does not determine the status of later patents covering improved inhalers, formulations, manufacturing methods, or specific drug products.

What is the Orange Book status of U.S. Patent 4,524,769?

The patent is an inhaler-device patent rather than a conventional drug-substance, drug-product, or method-of-use patent. The FDA Orange Book generally identifies patents submitted for approved drug products under the applicable NDA. A historical device patent of this type would not automatically appear as an Orange Book-listed patent merely because it was used with terbutaline or budesonide. (U.S. Food and Drug Administration [FDA], 2024; 21 U.S.C. § 355.)

The practical status is:

• It is not a current enforceable Orange Book barrier.
• It does not create a present 30-month stay risk under the Hatch-Waxman framework.
• An ANDA applicant does not need to make a current Paragraph IV certification against an expired patent.
• Any current Orange Book patents for a budesonide or bronchodilator product must be evaluated separately by product and NDA.

Orange Book status must be assessed at the approved-product level. The presence of budesonide or terbutaline in claim 7 or claim 8 does not convert the patent into a current drug-substance patent.

Which companies and products were historically relevant?

The patent is associated with the technical field that led to multidose dry-powder inhalers, including rotary or indexed dose-metering mechanisms. Astra and its inhalation-device businesses were major participants in this field, particularly through Turbuhaler-related products and inhaled budesonide and bronchodilator products.

The commercially relevant product categories include:

Product category	Relationship to Patent 4,524,769
Budesonide dry-powder inhalers	Potentially relevant to claim 8 if the device used the claimed membrane system
Terbutaline dry-powder inhalers	Potentially relevant to claim 7 if the device used the claimed membrane system
Capsule-based DPIs	Generally distinct because the dose is stored in a capsule rather than a movable perforated membrane
Blister-strip DPIs	Generally distinct where the dose carrier is a sealed blister strip
Reservoir DPIs	Potentially outside the claims if no perforated membrane meters the dose
Later rotary-dose inhalers	May implicate later patents even after this patent expired

The patent should not be treated as a patent on “Turbuhaler” generally. Later Turbuhaler generations and related devices were protected by additional patents with different claim sets, priority dates, and expiration dates.

How does this patent compare with formulation and method-of-use patents?

Patent 4,524,769 is primarily an apparatus patent. It does not broadly protect:

• Budesonide itself;
• Terbutaline itself;
• A specific salt or polymorph;
• A particular excipient system;
• A dry-powder formulation independent of the inhaler;
• A method of treating asthma or chronic obstructive pulmonary disease;
• A manufacturing process for micronized drug particles.

A product launch can therefore be blocked by other patent categories even though Patent 4,524,769 has expired.

Formulation patents

Formulation patents can cover:

• Particle engineering;
• Carrier particles such as lactose;
• Drug-excipient ratios;
• Moisture-control systems;
• Stabilizers;
• Agglomeration and deagglomeration behavior;
• Specific delivered-dose or fine-particle fractions.

Method-of-use patents

Method-of-use patents can cover:

• Treatment of asthma;
• Maintenance therapy;
• Specific dosing schedules;
• Patient populations;
• Combination therapy;
• Reduction of exacerbations or steroid exposure.

Manufacturing patents

Manufacturing patents can cover:

• Jet milling;
• Micronization;
• Controlled crystallization;
• Powder blending;
• Carrier coating;
• Filling and dose-metering processes;
• Device assembly and calibration.

These patent categories can create commercial barriers independently of the expired device patent.

What Paragraph IV challenges and generic-entry risks remain?

Patent 4,524,769 presents no current Paragraph IV challenge risk because it expired in 2002. A generic applicant would not need to challenge an expired patent to obtain approval.

The remaining risks depend on the target product:

Launch issue	Relevance
Expired device patent	No current blocking effect
Live formulation patent	May require Paragraph IV certification
Live method-of-use patent	May require a Paragraph IV certification or carve-out
Live device patent	May affect a device-specific ANDA or 505(b)(2) strategy
Regulatory exclusivity	Must be evaluated independently of patent expiry
Human-factors requirements	May delay or prevent substitution despite patent freedom
Device similarity	Can affect ANDA suitability and comparative performance

For a generic dry-powder inhaler, the major technical risks are dose uniformity, emitted dose, aerodynamic particle-size distribution, moisture sensitivity, flow resistance, and device usability. Those issues are regulatory and commercial barriers, not current rights under Patent 4,524,769.

Does the patent create biosimilar risk?

No. Biosimilar approval under section 351(k) concerns biological products, while terbutaline and budesonide are small molecules. Patent 4,524,769 is also an inhaler-device patent, not a biologic patent.

The relevant regulatory routes are generally:

• ANDA under section 505(j) for a sufficiently similar small-molecule product;
• 505(b)(2) for products requiring reliance on existing clinical data with differences in formulation, device, or route;
• NDA pathways for new drug-device combinations or materially different delivery systems.

What litigation and settlement issues are relevant?

The patent’s expiration eliminates the principal current litigation issue: a new infringement claim based solely on the patent cannot be maintained for post-expiration conduct. Historic litigation, licensing, or settlement arrangements could still matter for damages periods, covenants, or related patent families, but they do not revive the expired patent.

No settlement involving this patent can extend its statutory patent term. A commercial agreement could impose contractual restrictions, but those restrictions would be distinct from patent enforceability and would require analysis of the agreement itself.

The more significant litigation risk in the dry-powder inhaler sector historically has involved later patents covering:

• Specific inhaler mechanisms;
• Dose counters;
• Airflow and deagglomeration structures;
• Blister or cartridge systems;
• Powder formulations;
• Device-drug combinations;
• Manufacturing methods.

A freedom-to-operate review limited to Patent 4,524,769 would be incomplete for a current launch.

How strong was the patent estate, and what is its current strength?

Historical strength

The patent had meaningful historical scope because claim 10 reached beyond the detailed chamber-and-scraper arrangement in claim 1. Its technical focus on reproducible multidose loading addressed a core problem in dry-powder inhaler design.

Its limitations also created design-around opportunities:

• Use sealed blisters instead of perforated membranes;
• Use capsules instead of membrane-held powder;
• Use a bulk reservoir with a separate metering wheel;
• Use a linear strip rather than a rotating membrane;
• Avoid loading the membrane inside the device;
• Use a single cavity per dose instead of multiple equal perforations;
• Position the larger end of a tapered perforation away from the nozzle.

Current strength

Its current patent strength is zero as an enforceable U.S. right because the patent expired in 2002. Its remaining value is historical and analytical:

• It may explain design lineage;
• It may appear in prior-art searches;
• It may inform claim construction of related patents;
• It may help identify older inhaler architecture;
• It does not block a current U.S. product launch.

What are the likely generic launch scenarios?

A current entrant could pursue several routes:

1. A conventional dry-powder inhaler that uses a capsule, blister, or reservoir and avoids the claimed perforated membrane.
2. A product using a perforated membrane, relying on the expiration of Patent 4,524,769 while clearing later patents.
3. A 505(b)(2) product with a materially different device or formulation.
4. An ANDA product designed to match an approved reference product’s dose, performance, and device characteristics.

The most important current diligence questions are not directed to Patent 4,524,769 itself. They concern later U.S. patents, Orange Book listings for the target reference product, FDA device requirements, and formulation or manufacturing patents.

What geographic coverage did the patent provide?

U.S. Patent 4,524,769 provided rights only in the United States. Foreign counterparts, if any, required separate national filings and had separate expiration dates, prosecution histories, claim scope, and legal status.

The U.S. patent cannot establish freedom to operate in:

• Europe;
• Canada;
• Japan;
• Australia;
• China;
• Brazil;
• Other jurisdictions.

A global launch requires country-by-country review of the relevant patent family and later continuation or improvement patents. The expiration of the U.S. patent does not establish that corresponding foreign rights expired on the same date.

Key Takeaways

• U.S. Patent 4,524,769 covers a multidose dry-powder inhaler using a movable perforated membrane.
• Independent claim 1 requires a chamber, conduit, nozzle, membrane, dose-loading mechanism, and membrane-maneuvering mechanism.
• Independent claim 10 is broader because it omits several claim 1 components.
• Claims 7 and 8 cover the claimed inhaler containing terbutaline or budesonide; they do not claim those molecules broadly.
• Claims 9 and 11 narrow the dose to approximately 0.1 to 5 mg.
• Claim 5 requires frustoconical perforations oriented with the larger end toward the nozzle.
• The patent issued June 25, 1985, and ordinarily expired June 25, 2002.
• It creates no current U.S. infringement, Orange Book, Paragraph IV, or biosimilar barrier.
• Later device, formulation, method-of-use, and manufacturing patents remain the relevant sources of current launch risk.
• A current freedom-to-operate analysis must distinguish the expired patent from later inhaler patent families and product-specific Orange Book listings.

FAQs About U.S. Patent 4,524,769

Is U.S. Patent 4,524,769 still enforceable?

No. Its ordinary 17-year term expired on June 25, 2002.

Does the patent cover budesonide?

Only in the narrow context of claim 8, which requires an inhaler meeting claim 1 and containing budesonide. It does not claim budesonide as a compound or as a general inhaled formulation.

Does the patent cover a generic dry-powder inhaler?

Not automatically. The generic device must contain the claimed perforated-membrane dose-metering architecture and satisfy all limitations of an asserted claim.

Is a Paragraph IV certification required for this patent?

No. An expired patent does not create a current Paragraph IV certification obligation.

Can a later inhaler patent still block a product that avoids Patent 4,524,769?

Yes. Later patents may cover the device, formulation, manufacturing process, dose counter, airflow system, or method of use, regardless of the expiration of Patent 4,524,769.

References

1. 35 U.S.C. § 154. Patent term and patent rights.
2. 21 U.S.C. § 355. New drug applications and abbreviated applications.
3. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: The Orange Book.
4. U.S. Patent No. 4,524,769. (1985). Dosage inhalator. United States Patent and Trademark Office.

Drugs Protected by US Patent 4,524,769

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate

Foreign Priority and PCT Information for Patent: 4,524,769

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
Sweden	8104239	Jul 08, 1981

International Family Members for US Patent 4,524,769

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	23272
Australia	559297
Australia	8560882
Canada	1178151
Cyprus	1492