United States Patent 6,582,727: Scope, Claim Analysis, Expiration and Soft-Capsule Patent Landscape

US 6,582,727 covers non-gelatin soft-capsule shell compositions based on iota-carrageenan and modified starch. Its central technical limitation is a defined carrageenan-to-starch ratio combined with plasticizers, buffers, hydration-temperature requirements, and pressure-fusion properties. The patent does not claim a drug, active pharmaceutical ingredient, therapeutic indication, or finished medicinal product.

The patent’s ordinary 20-year United States term ended in 2021, based on its 2001 nonprovisional filing. No patent-term-extension pathway appears applicable to a capsule-shell technology. The claims therefore have no current United States patent-enforcement value, although the document remains relevant as prior art against later capsule-shell filings.

What technology does US 6,582,727 protect?

The patent protects films and capsule shells intended to replace conventional gelatin shells. The claimed films use:

Iota-carrageenan as the principal hydrocolloid;
Modified starch as the second principal gel former;
A specified ratio between iota-carrageenan and starch;
Water;
A plasticizer, commonly glycerin;
A buffer system;
Optional preservatives; and
Processing conditions that allow the wet film to fuse under pressure.

The commercial problem addressed by the patent is the manufacture of soft capsules without animal-derived gelatin. The claims focus on processability and shell performance, particularly the ability of the film to fuse during rotary-die or comparable encapsulation operations.

The patent is narrower than a general claim to all vegetarian capsules. A capsule must fall within the specified composition and, for the broader process-oriented claims, satisfy the specified ratio and fusion conditions.

What are the key patent details for US 6,582,727?

Item	Details
United States patent	US 6,582,727
Title	Capsule shell composition
Patent type	Utility patent
Technology	Iota-carrageenan and modified-starch soft-capsule films
Named owner at issuance	Warner-Lambert Company, according to the patent record
Priority date	April 7, 2000
United States filing	2001
Issue date	June 24, 2003
Principal claim categories	Dry films, wet films, capsule shells, composition ranges, pressure-fusion properties
Drug substance claimed	None
Orange Book status	Not an Orange Book-listed drug patent
Paragraph IV relevance	No direct Paragraph IV pathway for the capsule-shell claims
Ordinary United States term	Ended in 2021, subject to any recorded patent-term adjustment
Current enforcement status	Expired under the ordinary patent term

The patent record identifies the invention as a capsule-shell composition rather than a pharmaceutical composition containing a particular active ingredient. That distinction controls its regulatory and litigation profile. [1]

How do the independent claims define the protected subject matter?

Claim 1: dry film composition

Claim 1 requires a dried film composition suitable for soft capsules. It requires:

Gel formers comprising iota-carrageenan and modified starch;
A combined gel-former concentration of 42% to 84% by weight;
Water;
A plasticizer; and
A buffer.

The claim uses “consisting essentially of.” That transitional phrase generally permits components that do not materially alter the basic and novel characteristics of the composition, while excluding additives that materially change the claimed system. The central technical combination is the iota-carrageenan/modified-starch gel-former system.

The claim also requires the iota-carrageenan-to-modified-starch ratio to be at least 1.5:1. On its face, that is a strong numerical limitation. A formulation containing more starch than carrageenan would not satisfy this ratio if the ratio is construed exactly as written.

Claim 1 is composition-focused. It does not expressly require a fusion pressure, fusion temperature, or particular capsule-making machine.

Claim 2: composition with defined starches and hydration temperature

Claim 2 requires:

Iota-carrageenan;
At least one listed modified starch;
A starch hydration temperature below approximately 90°C; and
A modified-starch-to-iota-carrageenan ratio from 1.5:1 to 4.0:1.

The listed starches include hydroxypropylated tapioca starch, hydroxypropylated maize starch, acid-thinned hydroxypropylated corn starch, potato starch, and pregelatinized modified corn starches.

Claim 2 presents a drafting issue. Claim 1 expresses the ratio as iota-carrageenan to modified starch, while claim 2 expresses it as modified starch to iota-carrageenan. The two claims are not numerically equivalent. Claim 1 requires at least 1.5 parts carrageenan per part starch. Claim 2 requires 1.5 to 4 parts starch per part carrageenan.

That inconsistency would create a claim-construction issue in litigation. Courts would examine the issued patent, specification, prosecution history, and any certificate of correction rather than rely on a transcription alone. The ratio language in the issued document should control.

Claim 7: wet film and pressure fusion

Claim 7 is the most technically distinctive independent claim. It covers a wet-film composition comprising:

One or more specified starches;
Iota-carrageenan;
A minimum ratio between the components; and
A film capable of fusion under pressure of at least approximately 207 kPa, or 30 psi.

The supplied text states a ratio of “at least 1:5:1.” That expression is chemically and mathematically unclear and appears to be a transcription or formatting error. The dependent claims identify the intended range as 1.5:1 to 4:1 and, more narrowly, 2:1 to 3:1. The issued patent text and prosecution record would be necessary to determine whether the original claim used “at least 1.5:1.”

Claim 7 combines composition and functional performance. A competing formulation would need to meet both the ingredient limitations and the pressure-fusion capability.

What do the dependent claims add?

Claims	Added limitation
3	Glycerin as the plasticizer
4	Sodium or potassium salt as the buffer
5	Preservative
6	Capsule with a shell made from the claim 1 film
8	Ratio of 1.5:1 to 4:1
9	Ratio of 2:1 to 3:1
10	Buffer system; fusion pressure of 207 to 2,070 kPa and temperature of 25°C to 80°C
11	Melt temperature 4°C to 20°C above fusion temperature
12	Modified starch at 12% to 30% by weight
13	Modified starch at 20% to 30% by weight
14	Acid-modified hydroxypropylated corn starch
15	Iota-carrageenan at 6% to 12% by weight
16	Iota-carrageenan at 8% to 10% by weight
17	Iota-carrageenan at approximately 10% by weight
18	Standardized iota-carrageenan
19	Starch and carrageenan together at least 20% by weight
20	Plasticizer and buffer
21	Glycerin, sorbitol, propylene glycol, or polyethylene glycol
22	Plasticizer no more than 50% by weight

The dependent claims create commercially recognizable formulation targets. Claims 12 through 17 are particularly relevant because they define practical composition windows rather than merely naming ingredients.

A formulation containing approximately 10% standardized iota-carrageenan, 20% to 30% modified starch, glycerin, and a sodium or potassium buffer would have been a close technical match to several dependent-claim combinations during the patent term.

What formulations are protected by the patent?

The patent’s claim coverage can be grouped into four formulation classes.

Carrageenan-dominant compositions

Claim 1 requires an iota-carrageenan-to-starch ratio of at least 1.5:1. Such a composition is carrageenan-dominant by the claim’s stated ratio. The combined gel-former content must be 42% to 84% by weight.

Starch-dominant compositions

Claims 2 and 8 through 14 use a starch-to-carrageenan ratio of 1.5:1 to 4:1. These claims are directed to starch-dominant systems. The discrepancy with claim 1 is material and would affect infringement analysis.

Pressure-fusing wet films

Claims 7 through 11 require a wet film capable of fusing under pressure. The claimed operating window is:

Parameter	Claimed range
Fusion pressure	At least 207 kPa
Alternative pressure range	207 to 2,070 kPa
Fusion temperature	25°C to 80°C
Melt temperature differential	4°C to 20°C above fusion temperature
Preferred component ratio	2:1 to 3:1
Carrageenan concentration	6% to 12%, with narrower ranges of 8% to 10%

Finished capsules

Claim 6 extends the claim 1 composition into a physical capsule product. It requires a capsule having a shell and fill material, with the shell consisting essentially of the claimed film.

The claim does not require a specific fill. The fill could be a liquid, suspension, semisolid, oil, nutraceutical, pharmaceutical, or other encapsulated material, provided the shell meets the incorporated composition limitations.

How strong was the patent estate?

The patent had meaningful historical value but a relatively concentrated claim scope.

Strengths

It claimed a specific vegetarian soft-capsule material system rather than a broad result alone.
The claims included measurable ratios and concentration ranges.
The wet-film claims added manufacturing-performance limitations.
The starch Markush groups covered several commercially relevant modified starches.
Claims 10 and 11 tied the formulation to operational fusion conditions.

Weaknesses

The claims depended heavily on ingredient identity and numerical ratios.
The ratio language appears internally inconsistent across claims.
Several terms require technical interpretation, including “modified starch,” “standardized iota-carrageenan,” “hydration temperature,” and “capable of fusion.”
The use of “consisting essentially of” in claims 1 and 6 could limit permissible excipients.
The patent did not cover all non-gelatin capsule systems, including every hydroxypropyl methylcellulose, pullulan, or starch formulation.
Expiration removes the current exclusionary value of the claims.

The patent was strongest against a direct copy of the claimed carrageenan-starch system. It was weaker against formulations using a different hydrocolloid, a different starch chemistry, or a different capsule-manufacturing mechanism.

When did US 6,582,727 lose exclusivity?

The patent lost ordinary United States patent exclusivity in 2021. Patent term generally runs 20 years from the earliest effective nonprovisional filing date under 35 U.S.C. §154, subject to patent-term adjustment, terminal disclaimers, and limited statutory extensions. [2]

The patent was not a drug patent eligible for Hatch-Waxman patent-term extension under 35 U.S.C. §156 because the claimed invention is a capsule-shell composition, not an approved active pharmaceutical product. [3]

The expiration means:

No current United States patent license is required solely to practice the expired claims.
A manufacturer can use the claimed iota-carrageenan/modified-starch formulations in the United States.
The patent remains prior art for later patentability analysis.
Foreign family members, if any, required separate jurisdiction-by-jurisdiction review and may have expired earlier or later.

What is the Orange Book and Paragraph IV status?

US 6,582,727 should not be treated as an Orange Book patent. The FDA Orange Book lists patents associated with approved drug products, including certain drug substance, drug product, and method-of-use patents. A stand-alone capsule-shell patent is generally not listed as a product patent for the active drug. [4]

Accordingly:

There is no direct Orange Book listing analysis for US 6,582,727.
A generic applicant would not normally file a Paragraph IV certification against this patent through an ANDA.
Any Hatch-Waxman dispute involving a product using the capsule shell would more likely concern the active ingredient, dosage form, formulation, or method-of-use patents listed for that product.
The expired patent would not create a current 30-month stay or generic-launch block.

Which companies could have been affected by the patent?

The patent could have been relevant to companies manufacturing soft capsules with non-gelatin shells, including:

Catalent, through the former R.P. Scherer soft-capsule business;
Lonza and Capsugel businesses;
ACG Associated Capsules;
Qualicaps;
Suheung;
CapsCanada; and
Contract manufacturers producing vegetarian nutraceutical or pharmaceutical softgels.

These companies use multiple shell technologies. A company’s production of vegetarian capsules does not establish infringement. The relevant question would have been whether the specific shell formulation contained the claimed carrageenan and modified starch combination within the claimed ratio and process limits.

What manufacturing and intellectual-property barriers remain?

The patent’s expiration removes one barrier but not all commercial barriers. Current entrants may still face:

Trade-secret protection for starch pretreatment and hydration protocols;
Know-how relating to ribbon formation, viscosity control, and die sealing;
Equipment constraints involving temperature and pressure;
Customer qualification requirements;
Regulatory documentation for pharmaceutical excipients;
Separate patents covering HPMC, pullulan, carrageenan blends, capsule equipment, or filling processes;
Trademark and contractual restrictions; and
Foreign patent rights in jurisdictions where related family members had different expiration dates.

Manufacturing know-how can remain commercially important after patent expiration because the claimed composition alone does not disclose every operating parameter needed for consistent capsule production.

How does US 6,582,727 compare with competing capsule technologies?

Technology	Main shell material	Relationship to US 6,582,727
Gelatin softgel	Animal-derived gelatin	Generally outside the claimed carrageenan-starch system
HPMC softgel	Hydroxypropyl methylcellulose	Separate technical and patent category
Pullulan capsule	Fermented polysaccharide	Generally outside the claimed starch-carrageenan combination
Carrageenan-starch shell	Iota-carrageenan plus modified starch	Core technology claimed by US 6,582,727
Starch-only shell	Modified or pregelatinized starch	May avoid claims requiring iota-carrageenan
Carrageenan-only shell	Carrageenan without claimed starch	May avoid the combination claims
Hard vegetarian capsule	HPMC, pullulan, or starch	Different dosage form and manufacturing process

The patent should therefore be analyzed as an early softgel-shell patent within the broader vegetarian capsule field, not as a foundational patent covering every gelatin-free capsule.

What generic launch risks exist today?

For the United States, US 6,582,727 creates no current generic-launch risk because its claims expired in 2021. A pharmaceutical company launching a product in a non-gelatin soft capsule should still evaluate:

Patents covering the active ingredient;
Drug-product formulation patents;
Method-of-use patents;
Manufacturing-process patents;
Capsule-machine patents;
Foreign counterparts; and
Later patents claiming improved carrageenan, starch, HPMC, or pullulan systems.

The expired patent can be useful as a freedom-to-operate reference, but it cannot substitute for a current patent search covering later filings and unexpired family members.

What patent litigation or settlement agreements affect the patent?

No litigation, Paragraph IV dispute, or settlement agreement can be established from the claim text alone. The patent is not an Orange Book drug patent, so conventional Hatch-Waxman litigation is not the expected dispute mechanism.

Any historical enforcement would more likely have involved:

Contract-manufacturer disputes;
Patent litigation over capsule-shell composition;
Licensing of vegetarian softgel technology;
Trade-secret or know-how claims; or
Commercial disputes involving supply agreements.

The patent’s expired status sharply reduces the likelihood of current infringement litigation based solely on these claims.

Key Takeaways

US 6,582,727 claims non-gelatin soft-capsule films and shells using iota-carrageenan and modified starch.
The principal limitations are ingredient identity, component ratios, concentration ranges, hydration temperature, fusion pressure, and fusion temperature.
Claims 1 and 2 contain materially different ratio directions, creating a potential claim-construction issue.
Claim 7 contains an apparent ratio-formatting error in the supplied text; the issued patent should control.
Claims 3 through 5 and 20 through 22 narrow the invention through glycerin, buffers, preservatives, and specified plasticizers.
Claim 6 covers a capsule shell incorporating the claim 1 film.
The patent claims no active pharmaceutical ingredient or therapeutic use.
It is not an Orange Book patent and does not create a direct Paragraph IV pathway.
The ordinary United States patent term ended in 2021.
Current commercial risk lies primarily in later patents, foreign family members, manufacturing know-how, and unrelated formulation or drug patents.

FAQs

Does US 6,582,727 cover HPMC vegetarian capsules?

Generally no. HPMC capsules use hydroxypropyl methylcellulose and fall outside the claimed iota-carrageenan/modified-starch combination unless the accused shell also contains the required claimed components.

Can a company now manufacture a carrageenan-starch softgel in the United States?

The expired United States patent no longer blocks practice of its claims. A current freedom-to-operate review must still address later patents and other intellectual-property rights.

Does the patent cover the liquid or powder inside the capsule?

No. Claim 6 refers to a capsule with a shell and fill material, but the claimed limitations are directed primarily to the shell composition. The fill is not independently claimed as a particular drug or formulation.

Is a modified starch-to-carrageenan ratio of 1.5:1 commercially important?

Yes. That ratio is central to claims 2 and 8. A formulation’s ratio must be calculated using the same component definitions and basis used in the patent specification and prosecution record.

Could the patent block a nutraceutical softgel sold outside the United States?

The US patent cannot block conduct solely in another country. Any restriction would depend on enforceable foreign family members, local patent law, and the place of manufacture, sale, importation, or use.

References

United States Patent and Trademark Office. (2003). Capsule shell composition (U.S. Patent No. 6,582,727).
United States Code. (2023). 35 U.S.C. § 154, patent term.
United States Code. (2023). 35 U.S.C. § 156, patent term extension.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: The Orange Book.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	345113	⤷ Start Trial
Australia	6071500	⤷ Start Trial
Australia	735699	⤷ Start Trial
Brazil	0011489	⤷ Start Trial
Canada	2375652	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 6,582,727

Summary for Patent: 6,582,727