US Patent 7,691,411: Thyroid-Hormone Softgel Claims, Expiry, Orange Book Position and Generic Risk

US Patent 7,691,411 protects oral softgel formulations containing T3, T4, levothyroxine sodium, liothyronine sodium, or combinations of those hormones in a single-phase gelatin matrix. Its two independent claim families cover different plasticizing systems: glycerol-based matrices and sorbitol/sorbitan-based matrices.

The patent is composition-focused. It does not claim the thyroid hormones themselves, a disease-treatment method, a manufacturing process, or a particular dose strength. The principal infringement question is whether an accused softgel has the claimed hormone concentration, gelatin matrix, excipient system, water content, and single-phase structure.

The patent’s expected US term ended or is scheduled to end on November 23, 2025, based on the underlying priority date and ordinary patent-term calculation. Any patent-term adjustment must be confirmed from the USPTO patent-term record. The patent has no remaining practical regulatory exclusivity independent of its patent term. [1][2]

What does US Patent 7,691,411 protect?

The patent protects two related formulation platforms.

Claim family	Core matrix	Gelatin	Main plasticizer	Water	Hormone concentration
Claims 1-15	Single-phase uniform softgel	30-68%	Glycerol, 31-60%	1-10%	0.001-1%
Claims 16-32	Single-phase uniform softgel	30-70%	Sorbitol/sorbitans, 20-60%	1-10%	0.001-1%

The active ingredient must be selected from T3, T4, their sodium salts, or mixtures. In commercial thyroid products, the relevant active pharmaceutical ingredient is generally levothyroxine sodium, the sodium salt of T4.

The claims use “comprising” language. That generally permits additional ingredients unless the additional ingredient changes another required claim limitation. The claims therefore do not require an exact four-component formulation. An accused product may contain preservatives, dyes, ethanol, polyethylene glycol, propylene glycol, mannitol, or other excipients and still fall within the claims.

How should independent claims 1 and 16 be interpreted?

Claim 1: glycerol-based thyroid softgel

Claim 1 requires all of the following:

A pharmaceutical composition.
Oral administration.
A single-phase uniform softgel matrix.
T3, T4, their sodium salts, or mixtures as active principle.
Thyroid hormone concentration of 0.001% to 1% by weight.
Gelatin from bovine, pig, or fish origin at 30% to 68% by weight in the dried state.
Glycerol at 31% to 60% by weight in the dried state.
Water at 1% to 10% by weight in the dried state.

The “dried state” limitation is important. Percentages should be assessed against the dry formulation basis specified by the claim, not necessarily against the wet gelatin mass used during encapsulation.

The claim is broad as to:

Thyroid hormone identity;
Gelatin animal source;
Capsule strength;
Additional excipients;
Exact glycerol-to-gelatin ratio within the stated ranges.

The claim is narrower as to the physical structure. A conventional two-phase suspension, a liquid-filled capsule with a nonuniform fill, or a tablet would not literally satisfy the single-phase uniform-matrix limitation.

Claim 16: sorbitol/sorbitan-based thyroid softgel

Claim 16 covers a second formulation class requiring:

Gelatin at 30% to 70%;
Sorbitol or sorbitans at 20% to 60%;
Water at 1% to 10%;
The same 0.001% to 1% thyroid-hormone range; and
The same single-phase uniform softgel structure.

Claim 16 does not require glycerol. Claims 25-28 later add glycerol, propylene glycol, polyethylene glycol, or mannitol at 1%-10%.

The two independent claims are alternatives. A product cannot avoid the patent merely because it does not use glycerol if it falls within claim 16. Conversely, a glycerol product is not necessarily within claim 16 unless it also contains sorbitol or sorbitans in the required amount.

Which dependent claims materially expand or narrow protection?

The dependent claims create formulation subgroups rather than independent commercial concepts.

Claims	Added limitation	Commercial significance
2-3	Narrower glycerol range of 32-55% or 32.5-50%	Targets common glycerol-heavy softgel compositions
4-6	Gelatin pH of 3-10	Broad pH limitation with limited design-around value
7	Ethanol at 0.5-5%	Captures solvent-containing fills
8-11	Polyhydroxy or polyether alcohols at 3-10%	Covers common co-plasticizers
12-15	Excipients, release modifiers, preservatives, colorants	Broadens practical formulation coverage
17-18	Sorbitol/sorbitan narrowed to 25-55% or 25-50%	More commercially targeted sorbitol ranges
19-21	Gelatin pH of 3-10	Applies to the sorbitol family
22-24	Ethanol at 0.5-5%	Adds ethanol to sorbitol formulations
25-28	Glycerol, propylene glycol, PEG, or mannitol at 1-10%	Captures mixed-plasticizer systems
29-32	Release modifiers, preservatives, colorants	Adds routine finished-product components

Claims 12-15 and 29-32 are drafted broadly. Their practical value depends on whether the accused product already satisfies the independent matrix and hormone limitations. They do not independently protect a formulation that lacks the required thyroid-hormone softgel structure.

What formulation is most likely associated with this patent?

The patent is closely associated with the Tirosint levothyroxine softgel platform marketed by IBSA and its US commercial affiliate. Tirosint capsules use levothyroxine sodium in a gelatin-based softgel containing glycerol and water. The product’s formulation profile is consistent with the glycerol-based claim family. [3]

The patent does not cover every levothyroxine product. Standard tablets, liquid solutions, suspensions, powders, and softgels using materially different matrix compositions fall outside the literal scope unless they satisfy the claimed limitations or are found equivalent under the doctrine of equivalents.

What is the Orange Book status of US Patent 7,691,411?

US Patent 7,691,411 has been associated with the Tirosint capsule product in FDA patent-listing records. Orange Book listing gives an NDA holder a mechanism to notify applicants and trigger Hatch-Waxman patent procedures. It does not establish validity, enforceability, or infringement. [2]

The relevant regulatory distinction is:

Protection type	Position
FDA approval	Tirosint is an approved levothyroxine sodium capsule product
Small-molecule pathway	ANDA pathway under section 505(j)
New chemical entity exclusivity	Expired long before the patent term
Pediatric exclusivity	No continuing protection based on the patent claims
Patent listing	Relevant to ANDA certification while the patent remained unexpired
Biosimilar exclusivity	Not applicable

The patent does not protect a biologic. A biosimilar filing under the Public Health Service Act is therefore not the relevant competitive pathway. Generic entrants would use an ANDA, generally with a Paragraph IV certification if the listed patent remained unexpired and was asserted against the proposed product.

When does US Patent 7,691,411 lose exclusivity?

The patent’s ordinary term is tied to the earliest claimed priority date, reported as November 23, 2004. On that basis, the expected expiration date is November 23, 2025. [1]

Event	Date or status
Earliest priority basis	November 23, 2004
US patent grant	April 6, 2010
Expected ordinary expiration	November 23, 2025
Regulatory exclusivity	Expired
Post-expiration generic pathway	ANDA, subject to FDA approval requirements
Patent-term adjustment	Must be checked in the USPTO term record

After expiration, the claims cannot block a properly approved generic based solely on this patent. Other patents, including later formulation or liquid-product patents, may still affect market entry.

What Paragraph IV challenges and generic entry risks exist?

Before expiration, a generic levothyroxine softgel applicant could challenge the patent through a Paragraph IV certification. The likely arguments would be:

Invalidity for anticipation or obviousness;
Noninfringement based on a nonuniform fill;
Noninfringement based on matrix composition outside the claimed ranges;
Failure to meet the “dried state” percentage limitations;
Use of a different gelatin source or non-gelatin capsule;
Lack of a single-phase matrix;
Lack of the claimed thyroid hormone concentration.

The strongest design-around strategies would be to use:

A tablet or oral solution;
A two-phase suspension rather than a uniform matrix;
A capsule shell or matrix that is not gelatin-based;
A plasticizer outside the claimed glycerol and sorbitol/sorbitan ranges;
Water content outside the claimed range;
A formulation using a different carrier system;
A liquid solution marketed under a separate FDA approval.

A product that uses glycerol, gelatin, levothyroxine sodium, and water within the claimed ranges would present the highest literal-infringement risk.

How strong is the patent estate?

The patent has meaningful historical coverage of the original thyroid softgel technology but limited breadth outside that dosage form.

Strength factor	Assessment
Active ingredient scope	Broad across T3, T4, and sodium salts
Dosage-form scope	Narrowly limited to single-phase oral softgels
Excipient scope	Broad within glycerol and sorbitol/sorbitan systems
Manufacturing protection	No express process claims in the supplied claim set
Method-of-use protection	None in the supplied claim set
Dose-strength protection	No specific microgram strength
Design-around potential	Moderate to high
Post-expiration value	Limited for blocking generic entry
Validity pressure	Range overlap and softgel prior art would be central issues

The composition claims are easier to design around than a patent covering a unique release mechanism, manufacturing process, or therapeutic method. Their commercial value depended on the combination of the active ingredient, gelatin matrix, plasticizer ranges, and single-phase structure.

What patent litigation affects Tirosint and this patent?

The supplied claims do not establish litigation history, settlement terms, or the existence of a particular Paragraph IV case. Patent litigation must be evaluated from federal court dockets and FDA litigation records rather than from the patent document itself.

A litigation analysis would focus on:

Whether an ANDA applicant used a gelatin softgel;
Whether its fill was a single-phase matrix;
Its glycerol or sorbitol/sorbitan concentration;
Its dry-basis water percentage;
Whether the applicant made a Paragraph IV certification;
Whether the NDA holder obtained a 30-month stay;
Whether a settlement permitted an agreed launch date.

No settlement right or license is created by the patent claims. Public ownership and commercialization records identify IBSA as the principal patent and product entity. A distribution arrangement for Tirosint does not, by itself, establish a license to US Patent 7,691,411.

How does this patent compare with competing levothyroxine protection?

Product or platform	Typical form	Relationship to US 7,691,411
Tirosint	Levothyroxine sodium softgel	Closest product alignment
Synthroid	Tablet	Outside literal softgel scope
Levoxyl	Tablet	Outside literal softgel scope
Unithroid	Tablet	Outside literal softgel scope
Tirosint-SOL	Oral solution	Different dosage form and separate regulatory/patent analysis
Generic levothyroxine tablets	Tablet	Generally outside the claims
Generic levothyroxine softgels	Softgel	Highest potential claim overlap

The patent is therefore a product-specific barrier rather than a broad levothyroxine monopoly. Its competitive relevance is concentrated in softgel substitutes for Tirosint.

Key Takeaways

US Patent 7,691,411 covers thyroid-hormone softgels, not thyroid hormones generally.
Claims 1-15 focus on glycerol-based gelatin matrices.
Claims 16-32 focus on sorbitol/sorbitan-based gelatin matrices.
The critical limitations are single-phase uniform structure, gelatin matrix, dry-state excipient ranges, water content, and T3/T4 active ingredient identity.
Tirosint is the product most closely aligned with the claimed technology.
The patent’s expected ordinary expiration date is November 23, 2025.
FDA exclusivity and any new-chemical-entity protection are long expired.
Generic tablets and oral solutions generally do not fall within the claims.
A generic softgel using gelatin, levothyroxine sodium, glycerol or sorbitol, and in-range water content would face the greatest infringement risk.
No biologic or biosimilar pathway is implicated.
The patent has no supplied method-of-use or manufacturing claims.

FAQs

Does US Patent 7,691,411 cover levothyroxine tablets?

No. The independent claims require a single-phase uniform oral softgel matrix. A conventional levothyroxine tablet does not satisfy that dosage-form limitation.

Can a generic levothyroxine softgel avoid the patent by changing glycerol to sorbitol?

Not necessarily. Claims 16-32 separately cover sorbitol/sorbitan-based matrices. A sorbitol formulation must also be evaluated against the gelatin, water, hormone concentration, and single-phase limitations.

Does the patent cover T3 products such as liothyronine?

Yes, the claims expressly include T3 and its sodium salt, subject to the required softgel matrix and concentration limitations.

Is a gelatin-free thyroid softgel covered?

A gelatin-free product would not literally satisfy the independent claims, which require gelatin from bovine, pig, or fish origin. Doctrine-of-equivalents exposure would depend on the specific formulation and litigation record.

Does patent expiration eliminate all Tirosint generic-entry barriers?

No. Expiration of US Patent 7,691,411 removes this patent as a blocking right, but other listed patents, later-filed patents, regulatory requirements, formulation differences, and FDA approval timing may affect entry.

References

United States Patent and Trademark Office. (2010). US Patent No. 7,691,411, Pharmaceutical composition.
U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations: Orange Book.
U.S. Food and Drug Administration. (n.d.). Tirosint levothyroxine sodium capsules: Prescribing information.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	447939	⤷ Start Trial
Canada	2454050	⤷ Start Trial
Germany	60329968	⤷ Start Trial
Denmark	1433478	⤷ Start Trial
European Patent Office	1433478	⤷ Start Trial
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Details for Patent: 7,691,411

Summary for Patent: 7,691,411