United States Patent 4,800,079: Fenofibrate Granule Claims, Patent Scope, and Competitive Landscape

US Patent 4,800,079 covers a fenofibrate multiparticulate formulation in which micronized crystalline fenofibrate is embedded in the pores of a water-soluble inert matrix and applied to an inert core as a granule. The patent issued on January 24, 1989, to Laboratoires Fournier S.A. Its pre-URAA patent term expired no later than January 24, 2006. The patent therefore has no current blocking or Paragraph IV value, although its claims remain relevant to the historical development of micronized fenofibrate products and later formulation patents.

What does US Patent 4,800,079 protect?

The patent protects a specific granule architecture rather than fenofibrate generally. The required structure is:

An inert core.
A fenofibrate-containing layer.
A protective outer layer.
Fenofibrate in crystalline microparticles no larger than 30 microns.
The microparticles located within the pores of a water-soluble inert matrix.

The independent claim is claim 1. Claims 2 through 7 narrow the formulation by specifying matrix materials, core composition, protective-layer weight, dissolution performance, particle size, and starch type.

Claim	Principal limitation	Legal effect
1	Granules with inert core, fenofibrate layer, protective layer, crystalline fenofibrate particles no greater than 30 microns, and water-soluble porous inert matrix	Broadest claim; requires all structural elements
2	Matrix binder selected from methacrylic polymers, polyvinylpyrrolidone, cellulose derivatives, polyethylene glycols, or mixtures	Narrows claim 1 by defining the matrix chemistry
3	Core approximately 0.3-0.6 mm; glucose, sucrose, lactose, starch, or mixtures	Narrows the core dimensions and composition
4	Protective layer approximately 1% by weight and composed of specified polymeric materials	Adds outer-layer composition and weight
5	At least 65% of fenofibrate released in one hour in aqueous liquid	Adds a functional dissolution limitation
6	Microparticles smaller than 10 microns	Narrower particle-size range than claim 1
7	Maize starch used in the claim 3 core	Narrowest claim; depends on claims 3 and 1

How should claim 1 be construed?

Claim 1 has five material limitations that must be evaluated separately.

1. Multiparticulate granule

The claimed medicine must be in granule form. A conventional compressed tablet, powder blend, liquid suspension, or capsule containing ungranulated fenofibrate would not satisfy the claim without an equivalent granule structure.

The claim does not require a particular dosage strength, route of administration, capsule shell, tablet coating, or number of granules per dose.

2. Inert core

The core is a support structure. It must be inert in the formulation context and is positioned beneath the fenofibrate layer. Claim 3 identifies representative core materials and a diameter of approximately 0.3 to 0.6 mm.

The independent claim does not expressly impose the claim 3 size or material restrictions. A core outside those parameters could still fall within claim 1 if the remaining limitations are met.

3. Fenofibrate layer

Fenofibrate must be present in a distinct layer on the core. A formulation in which fenofibrate is distributed throughout the entire granule without a separate layer presents a stronger non-infringement position, although the result would depend on the manufacturing process and the construction of "layer."

4. Crystalline microparticles no greater than 30 microns

The particle limitation is central. Claim 1 requires fenofibrate in crystalline microparticles with dimensions not greater than 30 microns. Claim 6 narrows the size to less than 10 microns.

The claim uses a maximum dimension concept. Particle-size testing would therefore matter. A manufacturer could not rely solely on average particle size if a meaningful portion of particles exceeded the claimed upper limit. The relevant evidence would include laser diffraction data, microscopy, sampling methodology, and the definition of D90, D50, or maximum particle dimension used in the product specification.

5. Microparticles in pores of a water-soluble inert matrix

This is the principal structural distinction from a formulation that merely contains micronized fenofibrate. The fenofibrate particles must be included within the pores of an inert matrix that is soluble in water.

A formulation with micronized fenofibrate physically mixed with a soluble excipient may not meet this limitation if the particles are not embedded in or located within matrix pores. Conversely, a porous polymeric or binder-based matrix that dissolves in water is closer to the claimed structure.

What formulations are protected by claims 2 through 7?

Claims 2 through 7 define preferred embodiments of the core technology.

Matrix materials

Claim 2 covers matrices using:

Methacrylic polymers;
Polyvinylpyrrolidone;
Mixtures of those polymers;
Cellulose derivatives; and
Polyethylene glycols.

The claim language identifies these materials as binders. It does not limit the formulation to one named grade, molecular weight, or commercial supplier. The scope would depend on whether the material performs the claimed matrix function and falls within the claim construction applied to the listed class.

Core materials and dimensions

Claim 3 identifies:

Glucose;
Sucrose;
Lactose;
Equivalent materials;
Starch; and
Mixtures of those substances.

The core diameter is approximately 0.3 to 0.6 mm. Claim 7 narrows the starch option to maize starch.

The use of "equivalents" in claim 3 may create construction issues. It could be read as covering functionally similar saccharide materials, but it does not eliminate the need for an inert core or the claimed approximate size.

Protective layer

Claim 4 requires a protective layer representing approximately 1% by weight of each granule. It uses the same broad material groups identified for the matrix, including methacrylic polymers, polyvinylpyrrolidone, cellulose derivatives, and polyethylene glycols.

A product with a materially heavier coating could avoid literal infringement of claim 4 while remaining potentially relevant to claim 1, because claim 1 does not specify the one-percent limitation.

Dissolution performance

Claim 5 requires at least 65% fenofibrate release in one hour in an aqueous liquid. This is a functional limitation, not merely a formulation recipe.

The testing protocol matters. The claim does not specify pH, agitation speed, apparatus, surfactant concentration, temperature, volume, or analytical method in the supplied text. Those variables can materially affect the result. A claim 5 analysis would require comparison under the legally relevant test conditions, not a generic dissolution result.

When did US Patent 4,800,079 lose exclusivity?

The patent issued on January 24, 1989. Because it is a pre-URAA patent, the applicable term was generally 17 years from issue, subject to any terminal disclaimer, disclaimer, or patent-term adjustment affecting the calculation.[1]

Event	Date
US patent issued	January 24, 1989
Standard 17-year issue-based expiration	January 24, 2006
Current enforceability	None; term expired

No patent-term extension or regulatory extension can restore an expired patent. Patent 4,800,079 therefore cannot support a current US infringement action or a present Paragraph IV challenge.

What is the Orange Book status of US Patent 4,800,079?

The patent does not create current Orange Book exclusivity for fenofibrate products. The FDA Orange Book records patents and exclusivity associated with approved products, but an expired patent cannot block approval or commercial launch.[2]

Fenofibrate has been approved in multiple dosage forms and strengths, including products associated with Tricor and other branded and generic products. Orange Book relevance for fenofibrate has historically centered on later formulation and product patents rather than the expired term of US 4,800,079.

The patent's historical commercial relevance may have arisen from its relationship to early Fournier fenofibrate technology. Its present regulatory significance is limited to prior-art and patent-family analysis.

Which later patents are relevant to the fenofibrate formulation landscape?

US 4,800,079 sits within an earlier generation of fenofibrate formulation patents. Later patents generally pursued improved dissolution, bioavailability, micronization, dosage forms, and commercial product configurations.

Patent	General technology area	Relationship to US 4,800,079
US 4,895,726	Micronized fenofibrate formulation	Extends the commercial importance of particle-size reduction and dissolution improvement
US 5,880,148	Fenofibrate pharmaceutical composition technology	Represents later formulation development
US 6,074,670	Fenofibrate composition and bioavailability technology	Focuses on product-performance improvements
US 6,277,405	Later fenofibrate formulation technology	Relevant to branded-product and generic-entry analysis

These patents should not be treated as automatically covering the same invention. Their claims must be compared limitation by limitation. A later patent may cover a tablet, capsule, excipient system, dissolution profile, or bioavailability result without requiring the three-layer granule structure claimed in US 4,800,079.

How does US 4,800,079 compare with later fenofibrate patents?

The main technical distinction is the claimed location of the active ingredient.

Issue	US 4,800,079	Later fenofibrate patent strategies
Dosage architecture	Layered granules on inert cores	Granules, capsules, tablets, coated particles, or matrix systems
Active ingredient	Crystalline microparticles	Micronized or otherwise size-controlled fenofibrate
Particle size	Not greater than 30 microns; less than 10 microns in claim 6	Often linked to dissolution, bioavailability, or manufacturing parameters
Excipient role	Water-soluble porous inert matrix	May rely on surfactants, wetting agents, polymers, or other excipient systems
Performance limitation	At least 65% release in one hour in claim 5	Later claims may use different dissolution or pharmacokinetic parameters
Patent status	Expired in 2006	The listed later patents also have historical terms that have expired or reached their stated expiration dates

US 4,800,079 is therefore a formulation-architecture patent. It is narrower than a patent directed generally to micronized fenofibrate, but it is more technically specific because it requires a defined core-layer-coating arrangement and porous matrix environment.

What generic-entry risks existed for fenofibrate products?

The principal generic-entry risks historically came from later patents associated with approved branded products, not from US 4,800,079 after 2006.

A generic applicant could have faced several patent theories:

Literal infringement of a formulation claim involving micronized fenofibrate and specified excipients.
Infringement of a dissolution or bioavailability claim.
Infringement of a method-of-use claim, if the applicant sought a label covering a patented indication.
Patent litigation following an ANDA Paragraph IV certification.
Regulatory delay under the Hatch-Waxman framework if the patent was timely listed and the NDA holder filed suit within the statutory period.[3]

For US 4,800,079 specifically, a Paragraph IV certification would now have no practical blocking effect because the patent expired. A generic product can use the claimed granule concept without facing prospective infringement liability based on this patent.

Did US 4,800,079 cover a method of use or manufacturing process?

No. The supplied claims are composition claims directed to a medicine in granule form. They do not claim:

Treating hypertriglyceridemia;
Treating mixed dyslipidemia;
Reducing cholesterol;
Administering a particular dose;
A manufacturing process;
A dissolution-testing method; or
A specific patient population.

The patent's risk profile was therefore tied to the composition of the product. A process that produced the claimed composition could create infringement exposure indirectly, but the claims supplied do not independently claim the process.

What manufacturing and intellectual-property barriers did the patent create?

The patent imposed several technical design constraints:

Production of uniform inert cores in the 0.3-0.6 mm range;
Formation of a fenofibrate layer around the cores;
Generation or incorporation of crystalline particles at the claimed size;
Creation of a porous, water-soluble matrix;
Application of a protective layer;
Control of dissolution to achieve the claimed release threshold.

The most difficult limitation to verify commercially is the requirement that microparticles be located in matrix pores. Finished-product testing may not resolve that question without microscopy, spectroscopy, cross-sectional imaging, or process records.

The patent also created a potential manufacturing-equivalence issue. A competitor could use the same active ingredient and particle-size range but change the granulation method, matrix material, or coating architecture. That could avoid literal infringement if the resulting product did not have the claimed pore structure.

How strong was the patent estate for US 4,800,079?

The patent was technically meaningful but commercially narrow.

Factor	Assessment
Claim breadth	Moderate to narrow
Structural specificity	High
Dependence on particle size	High
Dependence on hidden product structure	High
Manufacturing detectability	Moderate to difficult
Current enforceability	None
Historical blocking value	Potentially relevant before expiration
Current generic-entry impact	None

Claim 1 is narrower than a broad micronized-fenofibrate claim because it requires a specific granule arrangement and porous matrix. Claims 2 through 7 are progressively narrower and more vulnerable to design-around strategies.

Claim 5 could have provided a useful performance-based fallback if a product met the one-hour release threshold. Claims 6 and 7 are more limited and would have applied only to products using sub-10-micron particles or maize-starch cores.

What litigation and settlement issues affected fenofibrate?

Fenofibrate generic-entry disputes in the US generally focused on later patents associated with branded dosage forms and formulation improvements. Those disputes could involve NDA holders, branded manufacturers, and ANDA applicants such as Teva, Mylan, Impax, and other generic companies.

US 4,800,079 should be separated from that later litigation history. Its expiration means:

It cannot support a current infringement case.
It cannot delay approval of a present-day ANDA.
It cannot support a current settlement-based launch restriction.
It does not create current revenue protection for a branded fenofibrate product.
Any historical settlement involving later patents does not extend its term.

A settlement may have affected launch timing for a particular generic product, but it would not revive or extend US 4,800,079.

What is the current commercial exposure associated with this patent?

The current direct revenue exposure is zero because the patent is expired. Historical revenue protection may have existed for products using the claimed granule architecture before January 2006, but the patent cannot now prevent a competitor from practicing the claims.

The commercial analysis should instead focus on:

Active or expired Orange Book-listed patents for the specific reference product;
Product-specific ANDA litigation;
Formulation differences between capsules, tablets, and granules;
Current regulatory exclusivity;
Patent term extensions for later patents;
Labeling and method-of-use restrictions.

Key Takeaways

US Patent 4,800,079 covers a layered fenofibrate granule, not fenofibrate as an active ingredient.
Claim 1 requires an inert core, fenofibrate layer, protective layer, sub-30-micron crystalline fenofibrate, and a water-soluble porous inert matrix.
Claim 6 narrows the particle size to less than 10 microns.
Claim 5 adds a release requirement of at least 65% in one hour.
Claims 2, 3, 4, and 7 specify matrix materials, core materials, protective-layer composition, core size, and maize starch.
The patent issued January 24, 1989, and its standard pre-URAA term expired January 24, 2006.
The patent has no current Orange Book blocking value or Paragraph IV significance.
Later fenofibrate patents, including US 4,895,726, US 5,880,148, US 6,074,670, and US 6,277,405, were more relevant to later branded-product and generic-entry disputes.
The patent's historical strength came from its detailed formulation architecture; its current legal strength is zero because the term has expired.

FAQs

Could a generic manufacturer launch a product practicing claim 1 today?

Yes. The patent term has expired, so US 4,800,079 cannot support a current US infringement claim.

Does micronized fenofibrate alone infringe US 4,800,079?

No. Micronization alone does not satisfy the claim. The product must also have the claimed inert core, fenofibrate layer, protective layer, and porous water-soluble matrix arrangement.

Does claim 5 cover every fenofibrate product releasing 65% in one hour?

No. The release threshold is only one limitation. The product must also satisfy the structural limitations incorporated from claim 1.

Is US 4,800,079 a patent on Tricor?

It is an early Fournier fenofibrate formulation patent associated with the development of fenofibrate products. It is not, by itself, a current patent barrier to Tricor or generic fenofibrate products.

Can a later patent extend the exclusivity period of US 4,800,079?

No. A later patent may protect a different formulation, dosage form, manufacturing process, or method of use, but it cannot extend the expired term of US 4,800,079.

References

United States Patent and Trademark Office. (1989). US Patent No. 4,800,079, pharmaceutical compositions containing fenofibrate.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book.
U.S. Food and Drug Administration. (2024). Abbreviated new drug application approvals and patent certification requirements.
United States Patent and Trademark Office. (1990). US Patent No. 4,895,726, fenofibrate pharmaceutical compositions.
United States Patent and Trademark Office. (1999). US Patent No. 5,880,148, fenofibrate pharmaceutical compositions.
United States Patent and Trademark Office. (2000). US Patent No. 6,074,670, fenofibrate compositions.
United States Patent and Trademark Office. (2001). US Patent No. 6,277,405, fenofibrate formulations.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	75940	⤷ Start Trial
Australia	601462	⤷ Start Trial
Australia	7660387	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 4,800,079

Summary for Patent: 4,800,079