Details for Patent: 6,143,329

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Summary for Patent: 6,143,329

Title:	Aqueous-based pharmaceutical composition
Abstract:	An aqueous pharmaceutical composition which is capable of being sprayed into the nasal cavity of an individual and which comprises: (A) a pharmaceutically effective amount of solid particles of medicament which is effective in treating a bodily condition by virtue of its being present on the mucosal surfaces of the nasal cavity; and (B) a suspending agent in an amount effective to maintain said particles dispersed uniformly in the composition and to impart to the composition the following thixotropic properties: (i) the viscosity of the position in unsheared form is relatively high, with the composition being in gel-like form; (ii) as the composition is subjected to shear (shaken) in preparation for spraying, the viscosity of the composition becomes relatively low and such that the composition in the form of a mist flows readily into the nasal passages for deposit on the mucosal surfaces of the nasal cavity; and (iii) in deposited form on the mucosal surfaces, the viscosity of the composition is relatively high and such that it resists being cleared from the mucosal surfaces by the inherent mucocillary forces which are present in the nasal cavity, a method of use of the composition and a method for preparation of the composition, including in preferred form the use of anti-inflammatory steroid, for example, trimcindone acetonide, and an odorless form of the composition.
Inventor(s):	Soo-Il Kim
Assignee:	Aventis Pharmaceuticals Inc
Application Number:	US09/315,454
Patent Claim Types: see list of patent claims	Use; Composition; Delivery;

US Drug Patent 6,143,329: Scope, Claims, Expiration, Orange Book Status, and Triamcinolone Nasal Spray Patent Landscape

US Patent 6,143,329 covers a propellant-free, aqueous triamcinolone acetonide nasal spray using a microcrystalline cellulose/carboxymethylcellulose suspending system to create thixotropic behavior. The patent claims the formulation, the spray-device combination, allergic-rhinitis treatment methods, and regional nasal deposition characteristics.

The patent’s commercial value was concentrated in the Nasacort AQ formulation and delivery system. Its ordinary 20-year patent term has expired, eliminating current patent-based exclusivity from this patent. Triamcinolone acetonide is a small molecule, so biosimilar rules do not apply. Current competition is governed primarily by FDA approval status, OTC availability, manufacturing capability, formulation differentiation, trademarks, and any later patents rather than by US Patent 6,143,329.

What does US Patent 6,143,329 cover?

The patent covers four related subject-matter groups:

1. An aqueous pharmaceutical composition containing solid triamcinolone acetonide particles.
2. A vessel and precompression pump containing and dispensing the composition.
3. Methods for treating allergic rhinitis.
4. Methods for depositing and retaining triamcinolone acetonide on nasal and sinus mucosal surfaces.

The central technical concept is a reversible viscosity change:

• The formulation is highly viscous while standing.
• Shaking reduces viscosity sufficiently for atomization.
• After deposition, the formulation returns to a higher viscosity and resists mucociliary clearance.

The principal formulation limitation is a suspending agent consisting of approximately 85% to 95% microcrystalline cellulose and 5% to 15% carboxymethylcellulose, based on the weight of that mixture. Independent claim 1 also requires:

Limitation	Claimed range or requirement
Water	At least about 85 wt.%
Triamcinolone acetonide particles	About 0.001 to 2 wt.%
Suspending agent	About 1 to 5 wt.%
Microcrystalline cellulose in suspending-agent mixture	About 85% to 95%
Carboxymethylcellulose in suspending-agent mixture	About 5% to 15%
Unsheared viscosity	About 400 to 800 centipoise
Sheared viscosity	About 50 to 200 centipoise
pH	About 4.5 to 7.5
Propellant	None
Antimicrobial compound	Required by claim 1

The open-ended term “comprises” means that additional ingredients generally do not avoid the claim if all required limitations remain present.

What are the independent claims in US 6,143,329?

Claim 1: Formulation claim

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

• An aqueous pharmaceutical composition.
• Capability of being sprayed into the nasal cavity.
• No propellant.
• A pH of approximately 4.5 to 7.5.
• At least approximately 85 wt.% water.
• Solid particles of triamcinolone acetonide.
• A microcrystalline cellulose/carboxymethylcellulose suspending system.
• Defined viscosity behavior before and after shear.
• An antimicrobial compound.

A competing product that uses triamcinolone acetonide in a solution rather than as solid suspended particles would fall outside the literal particle limitation of claim 1. A product using a different suspending system could also avoid literal infringement if it does not contain the claimed cellulose mixture, although an equivalence analysis would depend on the facts and the applicable legal record.

Claim 6: Device and composition combination

Claim 6 covers an article of manufacture containing:

• The thixotropic triamcinolone composition.
• A vessel.
• A precompression pump capable of spraying a full dose into the nostril.

This claim is narrower than a formulation-only claim because it requires the specified packaging and dispensing arrangement. It does not repeat every numerical limitation in claim 1. Its composition language is comparatively functional, requiring a suspension that becomes more flowable during shaking and more viscous after deposition.

Claim 13: Specific formulation and device

Claim 13 claims a formulation, vessel, and precompression pump containing:

• Triamcinolone acetonide.
• Microcrystalline cellulose and sodium carboxymethylcellulose.
• Polysorbate 80.
• Disodium edetate, also known as disodium ethylenediaminetetraacetate or EDTA.
• Benzalkonium chloride.
• Dextrose.
• Purified water.

This is the claim most closely associated with the commercial formulation architecture of Nasacort AQ. Because claim 13 is written with “comprising,” it is not limited to a formulation containing only those listed ingredients. It also does not expressly import all concentration and viscosity ranges from claim 1.

Claim 14: Allergic-rhinitis treatment method

Claim 14 covers administering the aqueous thixotropic composition by spraying a full dose into a nostril, with deposition on nasal mucosa and resistance to mucociliary clearance.

The claim is directed to a method of use rather than merely to the product. A method claim can be infringed by performance of the claimed treatment steps, subject to the relevant patent-law standards governing direct and induced infringement.

Claim 25: Nasal and sinus delivery method

Claim 25 covers delivering the composition to:

• The anterior regions of the nose.
• The frontal sinus.
• The maxillary sinuses.
• The mucosa overlying the turbinates and conchas.

This claim is technically important because it focuses on deposition location rather than only on drug identity or formulation ingredients. Claims 26 through 29 add the cellulose-based suspending-agent system and specified two-hour deposition percentages.

How do the dependent claims narrow the patent?

The dependent claims add excipients, dosage parameters, device features, treatment schedules, and deposition outcomes.

Claim group	Added limitation
Claim 2	0.004% to 0.02% quaternary ammonium antimicrobial and 0.01% to 0.5% chelating agent
Claims 3-4	0.001% to 0.01% dispersing agent; specifically Polysorbate 80 in claim 4
Claim 5	Dextrose
Claims 7-8	Antimicrobial or chelating agent in the device article
Claims 9-12	More than two doses, at least 120 doses, approximately 100 mg per dose, and approximately 55 mcg triamcinolone acetonide per dose
Claims 15-16	Once-daily administration, including multiple full doses
Claims 17-20	At least one hour of retention and specified two-hour deposition in the inferior concha, superior concha, and frontal cavity
Claims 21-24	Daily dosing ranges and one or two 55-mcg sprays
Claims 26-29	Cellulose suspending system, viscosity ranges, and regional deposition percentages

The numerical deposition claims are narrower and more difficult to read on a competing product unless the competitor has comparable clinical or imaging data. They are also more vulnerable to evidentiary disputes because infringement may require reliable testing of deposition or retention.

What formulation is associated with the patent?

The claimed formulation architecture corresponds to a preserved, aqueous nasal suspension containing triamcinolone acetonide. The principal functional ingredients are:

Ingredient	Technical role
Triamcinolone acetonide	Insoluble corticosteroid active ingredient
Microcrystalline cellulose	Structural suspending and viscosity-building component
Carboxymethylcellulose sodium	Rheology modifier and suspension stabilizer
Polysorbate 80	Wetting or dispersing agent
Benzalkonium chloride	Antimicrobial preservative
Disodium EDTA	Chelating agent
Dextrose	Tonicity or formulation-adjustment component
Purified water	Continuous aqueous phase

The claimed technology depends on particle suspension rather than complete dissolution. The cellulose combination gives the formulation a gel-like resting state while allowing reduced viscosity after shaking. The formulation therefore addresses three product-development problems simultaneously: dose uniformity, sprayability, and nasal residence time.

When did US Patent 6,143,329 expire?

US Patent 6,143,329 is an issued US utility patent with a 20-year term measured from the applicable nonprovisional filing date under the pre-Uruguay Round patent-term framework. Public patent records identify the patent as issued on November 7, 2000. Its ordinary patent term expired in 2018 based on the underlying US filing chronology, subject to any legally applicable patent-term adjustment or extension shown in the official patent record. The patent is no longer a live US exclusivity right. [1]

The expiration has several consequences:

• A new triamcinolone nasal spray does not need a license to practice the expired claims.
• The patent cannot support a current Paragraph IV litigation threat.
• The formulation concepts disclosed and claimed by the patent are available for use, subject to later patents, trade secrets, regulatory requirements, and other intellectual-property rights.
• Patent expiration does not eliminate trademark rights in names such as Nasacort.

The patent’s expiration date should be distinguished from regulatory exclusivity and market exclusivity. Those rights arise under the Federal Food, Drug, and Cosmetic Act and may expire on different dates.

What is the Orange Book status of US Patent 6,143,329?

The FDA Orange Book identifies patents and exclusivity associated with approved drug products, but Orange Book status must be evaluated against the specific NDA and product listing. A patent can be expired even if it historically appeared in the Orange Book.

For triamcinolone acetonide nasal spray, the relevant branded product is Nasacort AQ, associated with FDA-approved nasal-spray labeling and an NDA held within the Sanofi/Aventis commercial history. FDA labeling identifies triamcinolone acetonide as a corticosteroid nasal spray for allergic rhinitis. [2]

The commercial and regulatory position is:

Issue	Assessment
Patent 6,143,329	Expired
Current patent exclusivity from this patent	None
Active ingredient	Triamcinolone acetonide
Dosage form	Aqueous nasal suspension spray
Biosimilar pathway	Not applicable
Paragraph IV relevance today	None for this expired patent
OTC status	Nasacort Allergy 24HR was approved for nonprescription use
Main current barriers	FDA requirements, manufacturing, trademarks, later IP, and market access

FDA approved the prescription-to-OTC switch for Nasacort Allergy 24HR in 2013. The OTC product is marketed for relief of allergy symptoms, including nasal congestion, sneezing, and runny nose, under an FDA-approved labeling framework. [3]

Were there Paragraph IV challenges or settlements involving this patent?

A Paragraph IV certification is an ANDA applicant’s assertion that an Orange Book-listed patent is invalid, unenforceable, or not infringed. It is relevant only while a listed patent remains legally enforceable and listed against an NDA product.

Because US Patent 6,143,329 has expired, it cannot presently create a Paragraph IV stay or a current 30-month litigation stay. Any historical ANDA challenge would have had commercial significance before expiration, but the patent does not now block an ANDA or other lawful generic development.

No current exclusivity analysis should treat this patent as an effective barrier to entry. A historical settlement, if any, would not revive the expired patent or create a new term. A settlement could still have relevance to historical launch timing or damages, but it would not provide current patent exclusivity.

Which companies are associated with the triamcinolone nasal spray market?

The relevant commercial participants include:

Company or group	Role
Sanofi and predecessor companies	Historical developer and marketer of Nasacort products
FDA-approved generic manufacturers	Potential suppliers of triamcinolone acetonide nasal spray
Perrigo and other OTC manufacturers	Consumer-health and store-brand competitors in nasal allergy products
Retail pharmacy chains and private-label companies	Distribution and private-label commercialization
Contract manufacturers	Production of suspension, filling, pump assembly, and packaging

The branded product’s competitive position changed materially after the OTC switch. The market moved from a physician-prescription product protected by brand recognition and regulatory positioning toward a consumer-health category with store-brand and generic alternatives.

How strong was the patent estate for Nasacort AQ?

US Patent 6,143,329 was technically meaningful but commercially narrow in several respects.

Strengths

• It claimed the core cellulose-based thixotropic suspension concept.
• It combined formulation, viscosity, preservative, and delivery requirements.
• It included device claims that tied the formulation to a precompression pump.
• It included method claims directed to allergic-rhinitis treatment and mucosal deposition.
• It addressed practical product-performance attributes, including sprayability and residence time.

Limitations

• The patent covered a specific active ingredient, triamcinolone acetonide.
• Claim 1 required solid suspended particles and defined cellulose proportions.
• Several claims required precise concentration, viscosity, dosage, or deposition parameters.
• A competing product could seek design-around strategies using a solution, a different suspending agent, different rheology, or a different delivery system.
• The patent has expired.

The patent was stronger against a substantially identical suspension and pump presentation than against all triamcinolone nasal products. It was not a broad monopoly over intranasal corticosteroids, triamcinolone acetonide generally, or every nasal spray formulation.

What generic launch risks exist today?

A current competitor faces regulatory and commercial risks rather than a live barrier from Patent 6,143,329.

Regulatory risks

A generic or private-label product must satisfy FDA requirements for:

• Active ingredient identity and strength.
• Dosage-form performance.
• Spray-content uniformity.
• Delivered-dose uniformity.
• Particle-size distribution.
• Microbial quality and preservative effectiveness.
• Container-closure integrity.
• Pump performance.
• Stability and shelf life.
• Labeling and OTC monograph or application requirements.

Manufacturing risks

The cellulose suspension is sensitive to:

• Particle wetting.
• Mixing order.
• Hydration time.
• Shear history.
• Bulk viscosity.
• Pump compatibility.
• Dose uniformity over the life of the container.
• Preservative distribution.
• Settling and redispersion.

These factors may create manufacturing know-how and quality-control barriers even though the patent claims have expired.

Commercial risks

The main commercial risks are:

• Strong consumer recognition of Nasacort.
• Retail shelf access.
• Pharmacy and distributor contracts.
• Advertising and OTC brand competition.
• Price compression.
• Private-label substitution.
• Pump and packaging supply.

These are market barriers, not patent exclusions arising from US 6,143,329.

How does US Patent 6,143,329 compare with biosimilar and generic exclusivity?

Triamcinolone acetonide is a chemically synthesized small molecule. A competing product is therefore evaluated through an ANDA, an OTC pathway, or another applicable small-molecule route. The product is not a biologic, and a biosimilar application under section 351(k) of the Public Health Service Act is not the relevant pathway.

The practical distinction is:

Category	Applicability
Biosimilar interchangeability	Not applicable
Biologic patent dance	Not applicable
ANDA Paragraph IV	Historically relevant for listed patents, but not for this expired patent
OTC monograph route	Potentially relevant to nonprescription nasal allergy products
NDA or supplemental NDA	Relevant where the product does not qualify through an abbreviated route

Does US Patent 6,143,329 create current freedom-to-operate concerns?

The patent itself does not create a current US patent exclusion because it has expired. A freedom-to-operate review must still examine:

• Later patents claiming nasal suspension formulations.
• Later patents covering pump architecture or spray geometry.
• Packaging and container-closure patents.
• Manufacturing-process patents.
• Formulation patents assigned to later product developers.
• Trademark and trade-dress rights.
• Foreign patents, where commercialization occurs outside the United States.

The expired patent remains relevant as prior art. Its disclosures may affect the validity and scope of later patent claims directed to similar triamcinolone suspension systems.

Key Takeaways

• US Patent 6,143,329 covers a propellant-free, aqueous, thixotropic triamcinolone acetonide nasal suspension.
• The core formulation uses microcrystalline cellulose and carboxymethylcellulose to control suspension, sprayability, and nasal residence time.
• The patent includes composition, device, treatment-method, and nasal-deposition claims.
• Claim 13 specifically recites Polysorbate 80, EDTA, benzalkonium chloride, dextrose, water, triamcinolone acetonide, and a cellulose mixture.
• The patent’s ordinary US term expired in 2018.
• It provides no current Paragraph IV barrier, regulatory exclusivity, or biosimilar protection.
• Current competition depends on FDA compliance, manufacturing capability, market access, trademarks, and later patent rights.
• The patent remains relevant as prior art and as a technical reference for suspension nasal-spray development.

FAQs About US Patent 6,143,329

Is triamcinolone acetonide nasal spray still protected by US Patent 6,143,329?

No. US Patent 6,143,329 has expired and does not provide current US patent exclusivity.

Can a generic use the same microcrystalline cellulose and carboxymethylcellulose system?

Yes, the expired patent does not prevent use of its claimed formulation technology. A competitor must still satisfy FDA requirements and avoid infringement of any later unexpired patents.

Does the patent cover all Nasacort products?

No. It focuses on a particular aqueous suspension architecture, delivery system, and treatment methods. It does not cover every formulation or dosage form containing triamcinolone acetonide.

Is a triamcinolone acetonide nasal spray a biosimilar?

No. Triamcinolone acetonide is a small-molecule corticosteroid. Competing products use generic-drug or applicable OTC regulatory pathways, not biosimilar approval.

Can the expired patent be used to challenge a later patent?

Yes. The patent’s disclosure and claims may constitute prior art against later patent claims, subject to the later patent’s filing date, priority chain, statutory framework, and claim limitations.

References

1. United States Patent and Trademark Office. (2000). U.S. Patent No. 6,143,329: Aqueous pharmaceutical compositions and methods of use.
2. U.S. Food and Drug Administration. (n.d.). Nasacort AQ triamcinolone acetonide nasal spray prescribing information.
3. U.S. Food and Drug Administration. (2013). FDA approves first over-the-counter nasal steroid spray.
4. U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations: Orange Book.

Drugs Protected by US Patent 6,143,329

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

International Family Members for US Patent 6,143,329

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
African Regional IP Organization (ARIPO)	1045
African Regional IP Organization (ARIPO)	9901495
Austria	250432
Australia	3647197
Australia	737506
Bulgaria	103127