United States Drug Patent 7,101,569: Claim Scope, Patent Landscape, and Generic Entry Risk

U.S. Patent No. 7,101,569 protects a specific administration method for an immediate-release levothyroxine tablet. The method requires a tablet with a defined stability profile, dispersion in an aqueous medium for less than 10 minutes, and administration of the resulting medium. Claims 2 and 3 narrow the method by specifying acceptable liquids and a shorter dispersion period.

The patent does not broadly claim levothyroxine, all levothyroxine tablets, or every liquid formulation. Its commercial value depends on whether a marketed product satisfies the stability limitation and is directed to be dispersed before administration. The patent issued September 5, 2006. Its enforceability today depends on the effective patent-term calculation, maintenance-fee history, terminal disclaimers, and any applicable patent-term adjustment shown in the USPTO record. The issue date alone does not establish the expiration date. [1]

What does U.S. Patent 7,101,569 claim?

The independent claim combines four material elements:

Claim element	Required limitation
Active ingredient	Levothyroxine
Dosage form	Immediate-release pharmaceutical tablet
Stability	Loses less than about 0.7% potency per month for up to 18 months
Administration method	Place tablet in an aqueous medium, disperse for less than 10 minutes, then administer the medium

The claim is a method-of-use claim. It does not claim the tablet composition in isolation. A product could potentially fall outside the claim if it has the same active ingredient and dosage form but is not used through the claimed dispersion-and-administration process.

What is the scope of the stability limitation?

The phrase "loses less than about 0.7% potency per month for up to 18 months" is a substantive limitation, not merely a product description. A patent owner would need to show that the relevant immediate-release tablet meets the stated potency-loss threshold over the specified period.

The claim raises several technical questions:

Whether potency is measured against initial labeled potency or a different baseline.
Whether the monthly loss is calculated linearly, cumulatively, or through a validated stability model.
Whether the test uses accelerated or real-time storage.
Which storage conditions apply.
Whether "about 0.7%" permits a numerical range around 0.7%.
Whether the stability requirement applies to the tablet as manufactured, the tablet during shelf life, or both.

Those issues would affect infringement analysis. A generic applicant could challenge the claim by arguing that its product does not meet the stability threshold, that the claim is indefinite, or that the patent specification does not adequately support the claimed performance range.

How do claims 1, 2, and 3 differ?

Claim 1 is the controlling independent claim. Claims 2 and 3 are dependent claims and include every limitation of claim 1.

Claim	Additional requirement	Practical effect
1	Dispersion in an aqueous medium for less than 10 minutes	Broadest method claim
2	Aqueous medium is water, saline, soft drinks, or milk	Narrows the liquid category
3	Dispersion occurs for less than five minutes	Narrowest timing limitation

Claim 2 does not cover every aqueous liquid. It identifies four specific media: water, saline, soft drinks, and milk. A liquid that is aqueous but outside those categories may satisfy claim 1 but not claim 2.

Claim 3 depends on claim 2. It therefore requires use of one of the four listed media and dispersion for less than five minutes. A five-minute dispersion may fall outside claim 3 because the language is "less than five minutes," although claim construction would determine how precisely the time is measured.

What products could fall within the patent?

A product is exposed to claim 1 only if all required conditions are present. The following matrix illustrates the principal scenarios:

Product or use pattern	Likely claim exposure
Immediate-release levothyroxine tablet swallowed intact	Lower exposure to the claimed method
Immediate-release tablet dispersed in water for three minutes and administered	Potentially within claims 1, 2, and 3
Tablet dispersed in milk for seven minutes	Potentially within claims 1 and 2, not claim 3
Tablet dispersed in water for 12 minutes	Outside the literal time limitation of claim 1
Extended-release levothyroxine product dispersed in water	Outside the express "immediate release" limitation
Levothyroxine oral solution supplied already in liquid form	Does not practice the claimed tablet-dispersion method
Tablet with more than 0.7% monthly potency loss	Potentially outside the stability limitation
Tablet dispersed in an unlisted aqueous beverage	Potentially within claim 1, but not necessarily claim 2

The phrase "placing an immediate release levothyroxine pharmaceutical tablet ... in an aqueous medium" requires an act involving the tablet. A premanufactured oral solution would not ordinarily meet that limitation because it is not a tablet that is subsequently dispersed.

What formulations are protected by U.S. Patent 7,101,569?

The patent protects use of a stable, immediate-release levothyroxine tablet that can be dispersed rapidly before administration. The claims do not expressly require a particular excipient, particle-size distribution, binder, lubricant, coating, compression force, or manufacturing process.

That distinction matters. A formulation patent generally claims the composition itself, while this patent claims a use protocol tied to formulation performance. The patent can therefore reach different tablet formulations if they independently satisfy the claimed stability and administration requirements.

The claims also do not expressly cover:

Intravenous levothyroxine;
Injectable products;
Softgel capsules;
Extended-release products;
Liquid levothyroxine supplied in a bottle;
Nasal or transdermal delivery;
A tablet administered intact;
A tablet dispersed for 10 minutes or longer.

The specification and prosecution history could affect interpretation of "dispersing," "immediate release," "potency," and "about." The claim text alone does not resolve whether dispersion requires complete dissolution, physical breakup, or a uniform suspension.

When does U.S. Patent 7,101,569 lose exclusivity?

The patent issued on September 5, 2006. Under the Uruguay Round Agreements Act framework, utility patents generally expire 20 years after the effective nonprovisional filing date, subject to patent-term adjustment, patent-term extension, terminal disclaimers, and other statutory adjustments. [1, 2]

Event	Date or rule
Patent issue	September 5, 2006
Standard utility-patent term	20 years from the effective nonprovisional filing date
Patent-term adjustment	May extend the base term
Patent-term extension under 35 U.S.C. § 156	Generally relevant to regulatory review delays for eligible products
Maintenance fees	Required at 3.5, 7.5, and 11.5 years after issue
Public patent status	Determined from the USPTO prosecution and maintenance records

The patent's precise expiration date cannot be derived from the issue date or claim text. A definitive term analysis must account for the earliest effective filing date, any priority claims, patent-term adjustment, terminal disclaimer, and maintenance-fee status. If the patent's base term has expired, the claims no longer block generic entry even if the relevant FDA product remains marketed.

What is the Orange Book status of Patent 7,101,569?

A patent is listed in the FDA Orange Book only when an NDA holder submits it for an approved drug and the FDA accepts the listing under applicable regulatory rules. [3] The existence of U.S. Patent 7,101,569 does not establish that it was listed in the Orange Book.

The patent's claim type would create a potential listing issue because it is a method-of-use claim. FDA listing practice generally distinguishes between patents that claim the drug substance, drug product, or an approved method of use. A method claim is potentially listable when it corresponds to an approved use and meets FDA listing standards. [3]

The patent should not be treated as an Orange Book barrier without a product-specific listing in the relevant FDA publication. If listed against an NDA, an abbreviated new drug application applicant could address it through a Paragraph IV certification. If unlisted, the patent could still be asserted in district court, but it would not automatically create the same Hatch-Waxman notice and 30-month-stay framework associated with a listed patent. [4]

What Paragraph IV challenges could arise?

A generic applicant targeting an immediate-release levothyroxine tablet could use several possible certification positions:

Non-infringement

The applicant could state that its labeling instructs patients to swallow the tablet intact, not disperse it in water or another listed medium. It could also design labeling that omits the claimed administration method, subject to FDA labeling requirements and induced-infringement principles.

Invalidity

Potential invalidity theories include:

Anticipation by an earlier disclosure of dispersible levothyroxine tablets;
Obviousness based on known rapid dispersion of oral tablets;
Lack of written description for the precise stability limitation;
Lack of enablement across the claimed range;
Indefiniteness involving "about 0.7%," "potency," or "dispersing."

Failure to meet the stability limitation

A generic company could generate stability data showing that its tablet does not lose less than the claimed amount of potency per month for the required period. The strength of this defense would depend on test conditions, statistical treatment, batch selection, and the patent's specification.

Labeling-based defenses

Because the claim is a method claim, the approved generic label would be central. A label that directs intact administration is materially different from a label instructing the user to disperse the tablet in water, saline, a soft drink, or milk.

A Paragraph IV challenge would not automatically establish non-infringement. A patent owner could argue that foreseeable use, product instructions, promotional activity, or the product's design encourages the claimed method.

Which companies are challenging Patent 7,101,569?

The supplied patent and claim text do not identify a specific Paragraph IV challenger, ANDA number, district court case, settlement agreement, or licensing transaction. No company-specific challenge should be attributed to this patent without a matching FDA Orange Book record, Paragraph IV notice, or court docket.

The broader levothyroxine market has included branded and generic products from multiple manufacturers. FDA-approved levothyroxine products include tablets, capsules, and oral solutions, but approval of a competing levothyroxine product does not itself establish a challenge to this patent. [5]

What patent litigation affects levothyroxine products?

Levothyroxine litigation historically has involved product substitution, bioequivalence, formulation consistency, manufacturing controls, labeling, and patent rights. Those issues are distinct from infringement of Patent 7,101,569.

For this patent, the most relevant litigation questions would be:

Whether the accused product is an immediate-release tablet.
Whether the product meets the claimed potency-loss threshold.
Whether the defendant's label instructs dispersion.
Whether use in water, milk, saline, or soft drinks is intended or foreseeable.
Whether the patent was listed against the relevant NDA.
Whether the patent remained unexpired when the complaint was filed.

A litigation search should distinguish cases naming the patent number from cases involving levothyroxine generally. Patent-number-specific litigation is required before treating a broader levothyroxine dispute as relevant to this patent.

How strong is the patent estate?

Patent 7,101,569 appears narrow in claim architecture because it is limited to a particular administration method and includes a quantitative stability requirement. Its strengths are the combination of:

A defined dosage form;
A measurable stability threshold;
A short dispersion period;
Specific administration media in the dependent claims.

Its weaknesses are equally material:

It does not claim levothyroxine tablets generally;
It does not claim the formulation composition itself;
It may be avoided through intact administration;
It may be avoided through a different release profile;
The potency limitation may require extensive technical proof;
The term may have expired depending on the effective filing date and adjustments.

The patent is therefore more relevant to a dispersible-tablet product or label than to the general levothyroxine market.

What generic launch risks exist?

Launch strategy	Patent risk
Conventional tablet, intact administration only	Lower risk under the supplied claims
Tablet labeled for dispersion in water	Higher risk
Tablet labeled for dispersion in milk or soft drinks	Higher risk under claim 2
Dispersion period of less than five minutes	Highest exposure to claim 3
Oral solution	Lower risk under the tablet limitation
Extended-release tablet	Lower risk under the immediate-release limitation
Reformulated tablet failing the stability threshold	Potentially lower risk, subject to proof
Product with a carve-out excluding the claimed use	May reduce risk if FDA-approved labeling permits

The most important commercial distinction is between a generic tablet that competes through ordinary intact administration and a product marketed for rapid dispersion. The latter is more likely to implicate the claim set.

Does the patent create biosimilar risk?

No. Levothyroxine is a chemically defined small-molecule active ingredient, not a biologic. Biosimilar provisions under the Public Health Service Act do not apply. Competition proceeds through the ANDA pathway or, for certain products and formulations, other FDA approval routes. [4, 5]

What is the competitive landscape for levothyroxine?

The market includes branded and generic levothyroxine products, with competition based on dose availability, tablet consistency, substitution policy, formulation, price, and regulatory status. Relevant product categories include:

Conventional levothyroxine sodium tablets;
Softgel levothyroxine capsules;
Oral levothyroxine solutions;
Compounded preparations;
Immediate-release dispersible formats.

Patent 7,101,569 is most relevant to the last category. It is unlikely to control the entire levothyroxine market because ordinary tablets, softgels, and oral solutions do not necessarily practice the claimed method.

Key Takeaways

U.S. Patent 7,101,569 is a method-of-administration patent, not a broad levothyroxine composition patent.
Claim 1 requires an immediate-release tablet, less than 0.7% monthly potency loss for up to 18 months, dispersion in an aqueous medium for less than 10 minutes, and administration of that medium.
Claim 2 limits the medium to water, saline, soft drinks, and milk.
Claim 3 requires dispersion for less than five minutes and includes all limitations of claims 1 and 2.
Intact tablet administration, oral solutions, and extended-release products are important non-infringement positions.
The patent's exact expiration date requires the effective filing date and patent-term-adjustment record.
Orange Book listing and Paragraph IV exposure are product-specific and cannot be inferred from the patent number alone.
The patent is not relevant to biosimilar exclusivity because levothyroxine is a small-molecule drug.
Commercial risk is concentrated in dispersible immediate-release levothyroxine tablets and corresponding labeling.

FAQs

Can a generic levothyroxine tablet infringe if patients independently dissolve it?

Potentially, but infringement would depend on the relevant actors, the product's labeling and promotion, and whether the other claim limitations are met. Patient experimentation alone does not resolve induced-infringement or method-of-use issues.

Does claim 1 require complete dissolution of the levothyroxine tablet?

The supplied claim language requires "dispersing" the composition, not expressly complete dissolution. Whether dispersion means breakup, suspension, or complete dissolution would depend on the patent specification, prosecution history, and claim construction.

Can a manufacturer avoid claim 3 by instructing dispersion for exactly five minutes?

The literal language requires less than five minutes. An instruction for exactly five minutes would not satisfy that limitation literally, although infringement analysis could consider the actual product instructions, user practice, and equivalents.

Does a patent on rapid dispersion prevent approval of a conventional levothyroxine ANDA?

Not necessarily. FDA approval and patent infringement are separate inquiries. A conventional ANDA product with intact-administration labeling may have a stronger position if it does not practice the claimed dispersion method.

Can the patent cover a levothyroxine tablet dispersed in juice?

Claim 1 refers broadly to an aqueous medium, so an aqueous juice could potentially fall within claim 1. Claim 2 is narrower because it lists water, saline, soft drinks, and milk. Whether a particular juice qualifies under claim 2 would depend on its classification and claim construction.

References

United States Patent and Trademark Office. (n.d.). Patent term adjustment and patent term calculation resources. https://www.uspto.gov
United States Code. (2024). 35 U.S.C. §§ 154, 156, and 271. https://uscode.house.gov
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations, commonly known as the Orange Book. https://www.fda.gov
United States Code. (2024). 21 U.S.C. § 355(j). https://uscode.house.gov
U.S. Food and Drug Administration. (2024). Drugs@FDA: FDA-approved drugs. https://www.accessdata.fda.gov/scripts/cder/daf/

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Australia	2002240394	⤷ Start Trial
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Brazil	0207297	⤷ Start Trial
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Details for Patent: 7,101,569

Summary for Patent: 7,101,569