US Patent 6,258,808: Claim Scope, Expiration, Patent Landscape, and Generic Entry Analysis

US Patent 6,258,808 covers glyceride compositions made primarily from C12-C20 fatty acids, with particular emphasis on linoleic-acid and oleic-acid mono-, di-, and triglycerides derived from corn oil and glycerol. The broadest claim is a composition claim. The dependent claims narrow the composition by fatty-acid profile, manufacturing origin, purity, free-glycerol content, and gelatin encapsulation.

The patent does not claim a specific therapeutic indication, active pharmaceutical ingredient, dosing regimen, or method of treatment. Its commercial relevance therefore depends on whether a marketed product contains a composition that falls within the structural limitations of the claims.

What does US Patent 6,258,808 protect?

The patent protects a mixture of glycerides containing fatty-acid chains with 12 to 20 carbon atoms. The mixture must predominantly contain glycerides derived from linolenic acid, linoleic acid, and oleic acid. Later claims focus on compositions predominantly containing linoleic-acid and oleic-acid glycerides.

The claims cover:

Claim	Subject matter	Principal narrowing limitation
1	Broad glyceride composition	C12-C20 fatty-acid mono-, di-, and triglycerides; predominant linolenic, linoleic, and oleic components
2	Composition of claim 1	Predominantly linoleic- and oleic-acid glycerides
3	Composition of claim 1	Transesterification product; predominantly linoleic and oleic glycerides
4	Composition of claim 1	Transesterification product of corn oil and glycerol
5	Composition of claim 1	Linoleic- and oleic-acid glycerides constitute at least 85% of the whole composition
6	Composition of claim 1	Corn-oil/glycerol transesterification product with at least 85% linoleic- and oleic-acid glycerides
7	Composition of claim 1	Free glycerol below 1% by weight relative to free glycerol plus glycerides
8	Composition of claim 1	Encapsulation in a gelatin capsule

Claim 1 is the principal genus claim. Claims 2 through 8 are narrower positions that may be easier to distinguish analytically but are also easier to design around.

How broad is independent claim 1?

Claim 1 has four principal elements:

A composition.
A mixture of mono-, di-, and triglycerides.
Fatty-acid chains in the C12-C20 range.
Predominant representation of linolenic, linoleic, and oleic acid glycerides.

The claim does not require:

Corn oil as the source material.
Glycerol transesterification.
An 85% concentration threshold.
A free-glycerol specification.
A gelatin capsule.
A pharmaceutical active ingredient.
A particular therapeutic use.
A particular ratio between mono-, di-, and triglycerides.
A particular dosage form other than in dependent claim 8.

The absence of a required source material makes claim 1 materially broader than claims 4 and 6. A competitor could potentially fall within claim 1 even if it used another vegetable oil, a synthetic esterification route, or purified fatty-acid feedstocks, provided the final composition satisfies the fatty-acid and glyceride limitations.

What does “predominantly” mean in the claims?

“Predominantly” is a central claim-construction issue. The supplied claims do not define the term numerically. Its scope would ordinarily depend on the patent specification, prosecution history, examples, analytical methods, and any statements made during examination.

Claim 5 supplies an express 85% threshold for linoleic- and oleic-acid mono-, di-, and triglycerides. That threshold is not expressly imported into claim 1 or claim 2. A court would therefore be unlikely to assume automatically that “predominantly” means 85% in every claim.

Potential interpretations include:

More than 50% of the relevant glyceride fraction.
A qualitative predominance over other fatty-acid glycerides.
A specification-defined range.
A composition profile demonstrated by the patent examples.

The patent specification and prosecution record are essential to determine whether the patentee used “predominantly” consistently with the 85% limitation. Claim 5 may support a narrower numerical interpretation for that claim while leaving claim 1 broader.

How do the dependent claims narrow the patent?

Claims 2 and 3: fatty-acid composition and process origin

Claim 2 removes linolenic acid from the express predominant group and focuses on linoleic and oleic acid glycerides. Claim 3 adds a transesterification-product limitation.

The use of “transesterification product” raises a product-by-process issue. Under US patent law, a product-by-process claim generally turns on the properties of the claimed product, although the process limitation remains part of the claim. A composition made by a different process may still present infringement risk if the process produces the same claimed product and the product-by-process limitation is construed as limiting. The analysis depends on the claim language and controlling precedent. See Abbott Laboratories v. Sandoz, Inc., 566 F.3d 1282 (Fed. Cir. 2009).

Claims 4 and 6: corn oil and glycerol

Claim 4 is narrower because it requires a transesterification product of corn oil and glycerol. Claim 6 adds the 85% concentration threshold.

A product made from soybean oil, safflower oil, sunflower oil, or isolated fatty acids may avoid literal infringement of claims 4 and 6 if corn oil is a limiting source requirement. That change would not necessarily avoid claim 1 or claim 2, which do not require corn oil.

The commercial importance of the corn-oil limitation depends on whether the transesterification process produces a composition distinguishable from other sources. If the final fatty-acid glyceride profile is materially the same, claims 1, 2, 5, or 7 may remain more relevant than claims 4 and 6.

Claim 5: 85% linoleic and oleic glycerides

Claim 5 requires linoleic- and oleic-acid mono-, di-, and triglycerides to constitute at least 85% of the whole composition. The phrase “whole composition” is potentially significant because the claim does not expressly state whether the percentage is measured:

By weight.
By mole.
By chromatographic area.
Against total glycerides.
Against all excipients and capsule contents.

Claim 7 expressly uses “by weight,” but claim 5 does not. That difference may support an argument that claim 5 uses a different measurement basis, although courts generally seek a technologically coherent construction across the patent.

A formulation containing substantial surfactant, solvent, antioxidant, carrier oil, or capsule material may create a dispute over the denominator.

Claim 7: free-glycerol limitation

Claim 7 requires free glycerol below 1% by weight based on the combined weight of free glycerol plus mono-, di-, and triglycerides.

This limitation is analytically narrower than a general purity requirement. It does not necessarily limit:

Water.
Residual fatty acids.
Sterols.
Phospholipids.
Tocopherols.
Other unsaponifiable material.
Non-glyceride excipients.

The denominator excludes those components. A product may therefore satisfy claim 7 even if its total formulation contains more than 1% non-glyceride material, provided free glycerol remains below the specified ratio.

Claim 8: gelatin capsule

Claim 8 requires the composition to be encapsulated in a gelatin capsule. The claim is a dosage-form limitation, not a therapeutic-use limitation.

A liquid-filled hard-gelatin capsule and a soft gelatin capsule could both be relevant, depending on the specification’s construction of “gelatin capsule.” A vegetarian hydroxypropyl methylcellulose capsule would generally present a noninfringement position under a literal reading, although equivalence arguments could arise if the capsule material performs the same function in substantially the same way.

What is the likely patent expiration status?

US Patent 6,258,808 was issued in 2001. For a patent governed by the post-Uruguay Round patent-term rules, the ordinary term is 20 years from the earliest effective nonprovisional US filing date, subject to patent-term adjustment, terminal disclaimers, and any applicable patent-term extension. The issue date does not establish the expiration date. See 35 U.S.C. § 154.

On the available claim information, the patent should be treated as an old patent whose ordinary term likely ended before 2020. A definitive expiration analysis requires the patent’s earliest effective US nonprovisional filing date, any continuation or divisional priority, patent-term adjustment, terminal disclaimer, and maintenance-fee history.

The practical conclusion is that US Patent 6,258,808 is unlikely to provide a current enforceable exclusion right in 2026 if its ordinary 20-year term ran from a late-1990s filing. Patent expiration would eliminate infringement liability for activities occurring after expiration, although it would not eliminate historical damages claims for the enforceable period.

What is the Orange Book status of US Patent 6,258,808?

US Patent 6,258,808 is a composition patent, not an identified patent covering a named FDA-approved drug, method of use, or drug-delivery device. On the supplied information, there is no basis to treat it as an Orange Book-listed patent.

The FDA Orange Book generally lists patents submitted by an NDA holder for an approved drug product, including patents covering the drug substance, drug product, formulation, or approved method of use. A general glyceride-composition patent does not become an Orange Book patent merely because the composition could be used as a pharmaceutical excipient or delivery vehicle. See FDA, Approved Drug Products with Therapeutic Equivalence Evaluations.

The patent would therefore not ordinarily create an Orange Book-based Paragraph IV pathway unless it was specifically submitted in connection with an approved NDA and accepted for listing.

Are Paragraph IV challenges relevant?

Paragraph IV certification applies to an ANDA applicant challenging a patent listed in the Orange Book for a reference-listed drug. It is not a general procedure for challenging any pharmaceutical patent.

For US Patent 6,258,808:

A Paragraph IV challenge would be relevant only if the patent were listed against an FDA-approved reference product.
An ANDA applicant would need to address the listed patent under 21 U.S.C. § 355(j)(2)(A)(vii)(IV).
If the patent is expired, an ANDA applicant would not normally need to certify that the patent is invalid or not infringed as a basis for immediate generic approval.
A composition patent outside the Orange Book may still be asserted under ordinary patent litigation, but it would not generate the standard Orange Book Paragraph IV litigation framework.

The more relevant generic-entry issue is whether a marketed product contains the claimed glyceride composition and whether any unexpired related patents protect its formulation, use, manufacturing process, or dosage form.

What generic entry risks exist?

Risk from a composition that resembles corn-oil glyceride products

A product is most exposed if laboratory analysis shows:

C12-C20 fatty-acid glycerides.
Predominant linoleic and oleic acid content.
A mixture of mono-, di-, and triglycerides.
At least 85% linoleic- and oleic-acid glycerides.
Less than 1% free glycerol on the claim 7 denominator.
Encapsulation in gelatin.

Claims 1, 2, 5, and 7 could collectively cover a broad commercial composition even if claims 4 and 6 are avoided by changing the source oil or manufacturing process.

Design-around options

Potential design-around positions include:

Use a fatty-acid profile in which linoleic and oleic glycerides are not predominant.
Use fatty acids outside the C12-C20 range in a material portion of the glyceride mixture.
Eliminate one of the required glyceride classes, if the claim is construed to require mono-, di-, and triglycerides collectively.
Use a non-corn-oil source to avoid claims 4 and 6.
Keep the linoleic- and oleic-glyceride fraction below 85% to avoid claims 5 and 6.
Use a capsule made from a non-gelatin material to avoid claim 8.
Maintain a composition with more than 1% free glycerol to avoid claim 7, although that may create product-quality or regulatory problems.
Use a formulation that does not contain the claimed composition as a separate mixture.

The first five strategies are more technically credible than intentionally increasing free glycerol. Deliberate impurity addition may create manufacturing, stability, safety, and regulatory issues.

How strong is the patent estate?

Claim-strength assessment

Issue	Assessment
Independent composition claim	Broad, but dependent on interpretation of “predominantly”
Source limitation	Stronger in claims 4 and 6, but easier to design around
Numerical threshold	More objective in claims 5 and 6
Free-glycerol limitation	Objectively testable but denominator-sensitive
Capsule limitation	Narrow and readily designable around
Therapeutic scope	None stated in the supplied claims
Manufacturing protection	Limited; process is used mainly to define the product
Current exclusivity	Likely ended under the ordinary patent term
Litigation leverage	Low if the patent is expired; potentially relevant only to historical conduct or related unexpired patents

The estate appears to have been designed to protect a particular glyceride composition and its commercial presentation rather than a complete drug product. Claim 1 has the greatest breadth but also the most substantial interpretation risk. Claims 5 and 7 provide measurable specifications that may be stronger in litigation but are narrower.

What manufacturing and analytical issues affect infringement?

A freedom-to-operate analysis would require testing the finished composition, not merely reviewing the supplier’s declared oil source.

Relevant analytical methods may include:

Gas chromatography for fatty-acid composition.
High-performance liquid chromatography or equivalent methods for mono-, di-, and triglyceride distribution.
Quantitation of free glycerol.
Measurement of total glyceride content.
Verification of the fatty-acid chain-length distribution.
Identification of residual free fatty acids, sterols, phospholipids, and unsaponifiable components.
Capsule-shell composition testing.

The critical issue is whether the claim percentages are calculated from the same analytical population and denominator. For example, “85% of the whole composition” may produce a different result from “85% of total glycerides.” A technical expert would need to align the claim language with the patent specification’s disclosed testing methods.

What geographic coverage does the patent have?

US Patent 6,258,808 provides rights only in the United States. It does not, by itself, establish protection in:

The European Union.
The United Kingdom.
Canada.
Japan.
China.
Australia.
India.
Brazil.

International protection would require corresponding national or regional patents. A patent-family search would be necessary to identify foreign counterparts, their legal status, and their expiration dates. No foreign patent rights can be inferred from the US patent number or the supplied claims.

What litigation or settlement issues affect the patent?

The supplied claims do not identify litigation, settlements, licenses, or ownership transfers. A patent litigation assessment should distinguish among:

Infringement suits involving US 6,258,808.
Declaratory-judgment actions.
Post-grant or inter partes review proceedings.
Assignments and security interests.
License agreements.
Settlement agreements containing covenants not to sue.
Related continuation patents with later expiration dates.

An expired patent can still appear in historical litigation records, but it would not normally support prospective exclusion. A later continuation or divisional patent could have a different expiration date and materially alter the freedom-to-operate analysis.

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

US 6,258,808 is structurally different from common pharmaceutical patent categories:

Patent category	Present in supplied claims?	Commercial effect
Active pharmaceutical ingredient	No	Does not protect a specific drug molecule
Salt, polymorph, or crystal form	No	No solid-state protection shown
Drug formulation	Limited	Protects a glyceride composition; no active-drug formulation claimed
Manufacturing process	Limited	Transesterification appears as a product characterization
Method of treatment	No	No indication or dosing exclusivity
Dosage form	Yes, narrow	Gelatin capsule in claim 8
Device or delivery system	No	No device claim shown
Biosimilar-related protection	No	The claimed subject matter is not a biologic

The patent therefore should not be analyzed as a conventional small-molecule drug patent or biologic patent. Its principal risk is formulation- or excipient-composition risk.

Key Takeaways

US Patent 6,258,808 claims glyceride compositions dominated by linoleic and oleic acid mono-, di-, and triglycerides.
Claim 1 is the broadest claim and does not require corn oil, transesterification, an 85% threshold, or gelatin encapsulation.
Claims 4 and 6 specifically target corn-oil/glycerol transesterification products.
Claims 5 and 6 impose an 85% linoleic- and oleic-glyceride requirement.
Claim 7 imposes a free-glycerol limit below 1% under a specified denominator.
Claim 8 is limited to gelatin-capsule presentation.
The patent does not claim an active drug, therapeutic indication, dosing regimen, or biologic.
It is unlikely to be an Orange Book patent absent a specific NDA listing.
Paragraph IV relevance exists only if the patent was listed against an approved drug product.
The patent appears to be an old patent likely beyond its ordinary 20-year term, but the exact expiration date requires the complete prosecution and maintenance record.
Current commercial risk is more likely to arise from related, later-filed patents than from the supplied claims themselves.
Laboratory characterization of the finished composition is central to any infringement or design-around analysis.

FAQs About US Patent 6,258,808

Does US Patent 6,258,808 protect corn oil itself?

No. The claims protect glyceride compositions and, in narrower claims, a transesterification product made from corn oil and glycerol. Unmodified corn oil is not the claimed composition.

Does the patent cover omega-3 fatty-acid products?

Not generally. Claim 1 mentions linolenic acid, but the claims focus on C12-C20 fatty-acid mono-, di-, and triglycerides predominantly containing specified fatty acids. A product dominated by long-chain EPA or DHA triglycerides would not automatically fall within the claims.

Can a non-gelatin softgel avoid the patent?

It may avoid claim 8 if the capsule is not made from gelatin. That change would not avoid claims 1 through 7 if the encapsulated composition independently satisfies those claims.

Is a product made from sunflower oil outside the patent?

It may avoid claims requiring a transesterification product of corn oil and glycerol, particularly claims 4 and 6. It could still implicate broader composition claims if its final glyceride profile satisfies claims 1, 2, 5, or 7.

Does patent expiration eliminate all regulatory barriers to commercialization?

No. Patent expiration removes patent-based exclusion for the expired claims, but FDA requirements, formulation quality standards, labeling rules, manufacturing controls, and any unexpired related patents remain separate issues.

References

United States Patent No. 6,258,808. (2001). Glyceride composition claims 1-8. United States Patent and Trademark Office.
United States Code, Title 35, § 154. (2024). Contents and term of patent; provisional rights.
United States Code, Title 21, § 355(j)(2)(A)(vii)(IV). (2024). Abbreviated new drug applications and patent certifications.
Abbott Laboratories v. Sandoz, Inc., 566 F.3d 1282 (Fed. Cir. 2009).
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. FDA.

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
United Kingdom	9113872	Jun 27, 1991

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	403436	⤷ Start Trial
Austria	A129892	⤷ Start Trial
Australia	1852792	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 6,258,808

Summary for Patent: 6,258,808