United States Patent 7,045,145: Scope, Claim Construction, Expiration, and Transdermal Contraceptive Patent Landscape

U.S. Patent No. 7,045,145 covers a hormone-containing transdermal patch that combines levonorgestrel and an estrogen with a specific adhesive matrix and a four-component permeation-enhancer system. The central technical limitation is the enhancer mixture of dimethyl sulfoxide, a C8-C20 fatty alcohol ester of lactic acid, a C1-C4 alkyl ester of lactic acid, and capric acid in a defined ratio.

The patent is important because it claims both the product and the contraceptive-use regimen. Its strongest protection is concentrated in claims requiring the specified enhancer combination, the ratio range, the polyacrylate adhesive system, and levonorgestrel plus ethinyl estradiol. The patent does not broadly cover every levonorgestrel/estrogen patch.

Based on the patent's filing chronology, the ordinary 20-year U.S. patent term ran from the earliest effective nonprovisional filing date and would have ended in 2021, subject to any patent-term adjustment. The patent is therefore not a current barrier to launch unless an unexpired term adjustment, terminal disclaimer, or related continuation patent materially changes the analysis. The patent itself is not a biosimilar patent and does not create biologic exclusivity.

What does U.S. Patent 7,045,145 cover?

The patent covers two related categories:

A physical transdermal delivery system.
A method of controlling fertility using that system.

The independent product claim is claim 1. The independent method claim is claim 18.

Claim category	Independent claim	Core subject matter
Product	1	Backing layer plus adhesive polymer matrix containing hormones and a defined permeation-enhancer mixture
Fertility-control method	18	Applying the system to skin and replacing it weekly for three of four successive weeks
Product dependent claims	2-17	Specific hormones, polymers, enhancer ingredients, delivery rates, patch dimensions, and blood concentration
Method dependent claims	19-34	The same technical limitations applied to the fertility-control method

The claims use “comprising,” which generally leaves the claim open to additional ingredients or structural components. A competing product could therefore contain other excipients and still fall within the claims if it includes all required elements.

The claims do not require a particular brand name, manufacturing company, commercial package, or trade name. They are composition and method claims.

What are the key limitations of claim 1?

Claim 1 requires all of the following:

A backing layer.
An adhesive polymer matrix affixed to that backing layer.
A humectant/plasticizer at about 0% to about 10%.
An adhesive copolymer at about 20% to about 70%.
A permeation-enhancer combination at about 10% to about 60%.
A progestin hormone.
An estrogen hormone.
A mixture containing:
- Dimethyl sulfoxide, or DMSO.
- A C8-C20 fatty alcohol ester of lactic acid.
- A C1-C4 lower alkyl ester of lactic acid.
- Capric acid.
A component ratio of approximately 2:1:1:0.8 to 6:1:1:0.8.

The claim is not satisfied merely because a patch contains levonorgestrel and ethinyl estradiol. The accused product must also contain the claimed adhesive matrix and enhancer system, or an equivalent that survives any doctrine-of-equivalents analysis.

Claim 1 limitation map

Limitation	Scope
Dosage form	Transdermal delivery system
Support	Backing layer
Drug-containing layer	Adhesive polymer matrix
Humectant/plasticizer	0%-10%
Adhesive copolymer	20%-70%
Enhancer combination	10%-60%
Progestin	Broad in claim 1; levonorgestrel in claim 2
Estrogen	Broad in claim 1; ethinyl estradiol or 17 beta-estradiol in claim 3
DMSO	Required
Fatty alcohol lactate	C8-C20 species
Lower alkyl lactate	C1-C4 species
Capric acid	Required
Enhancer ratio	About 2:1:1:0.8 to 6:1:1:0.8

The use of “about” creates potential claim-construction issues. Courts commonly interpret “about” in light of the specification, prosecution history, measurement method, and technical context. The permitted numerical deviation cannot be determined from the claim text alone.

How do claims 2 through 17 narrow the product protection?

Claims 2 through 17 create progressively narrower product positions.

Claim	Added limitation
2	Progestin is levonorgestrel
3	Estrogen is ethinyl estradiol or 17 beta-estradiol
4	Humectant/plasticizer is polyvinylpyrrolidone/vinyl acetate
5	PVP/VA contains approximately 60% PVP and 40% vinyl acetate
6	Adhesive copolymer is a polyacrylate copolymer
7	Polyacrylate contains 2-ethylhexyl acrylate
8	Polyacrylate further contains about 3%-60% vinyl acetate
9	Fatty alcohol lactate is lauryl lactate
10	Lower alkyl lactate is ethyl lactate
11	Enhancers fall within the specified ratio range
12	Enhancer ratio is approximately 4:1:1:0.8
13	EE delivery is 10-50 micrograms/day and LNG delivery is at least 20 micrograms/day
14	LNG delivery is at least 30 micrograms/day
15	LNG produces a blood concentration of at least 1,000 pg/mL
16	Matrix thickness is approximately 10-300 microns
17	Maximum surface area is 12.5 cm²

The narrowest practical product combination is reflected in claims 12-17: a levonorgestrel/ethinyl estradiol patch using a 4:1:1:0.8 enhancer ratio, defined delivery rates, a blood concentration threshold, a matrix thickness range, and a maximum surface area.

What do claims 18 through 34 protect?

Claim 18 protects a fertility-control method rather than the patch as a standalone product.

The method requires:

Applying the patch to the skin of a subject seeking fertility control.
Using the same matrix and enhancer architecture recited in claim 1.
Delivering one or more fertility-control hormones.
Including both a progestin and an estrogen.
Delivering at least a minimum effective daily dose.
Providing fertility control for approximately one to seven days.
Replacing the patch once each week for three of four successive weeks of a menstrual cycle.
Continuing the regimen for successive menstrual cycles as desired.

This creates a separate infringement pathway. A party may avoid a product claim but still face method-claim exposure if it instructs users to apply and replace a covered patch under the claimed weekly regimen.

Method claims 30-32 are narrower because they require ethinyl estradiol and levonorgestrel, defined delivery rates, and, in claim 32, an LNG blood concentration of at least 1,000 pg/mL.

How strong is the patent estate for levonorgestrel and ethinyl estradiol patches?

The patent's technical scope is meaningful but narrow.

Strengths

The patent combines several limitations that can make a conventional anticipation attack more difficult:

Two hormones in one adhesive matrix.
A specific four-component enhancer combination.
A defined enhancer ratio.
A polyacrylate adhesive system.
A weekly contraceptive regimen.
Quantitative delivery-rate and blood-concentration limitations.

A reference disclosing a levonorgestrel/ethinyl estradiol patch without the claimed DMSO/lactate/capric-acid mixture would not necessarily anticipate claim 1.

Weaknesses

The same limitations create noninfringement and invalidity opportunities:

A patch using a different permeation enhancer may avoid the claims.
A patch using a different ratio may fall outside the literal range.
A patch using a silicone, rubber, polyurethane, or non-polyacrylate adhesive may avoid narrower claims.
A product using norelgestromin rather than levonorgestrel would not satisfy claims 2, 19, or 30-32.
A nonweekly regimen may avoid the central method claim.
The broad percentage ranges may raise enablement, written-description, indefiniteness, or anticipation issues depending on the specification and prosecution history.
The claims do not specify a single commercial formulation, which may make infringement testing more fact-intensive.

The broadest claim is not a blanket patent on hormonal contraception by patch. It is a combination claim requiring a particular delivery architecture.

What formulations are protected by the patent?

The formulation most directly targeted by the dependent claims has the following profile:

Formulation component	Claimed limitation
Progestin	Levonorgestrel
Estrogen	Ethinyl estradiol or 17 beta-estradiol
Adhesive	Polyacrylate copolymer
Acrylic monomer	2-ethylhexyl acrylate
Optional copolymer component	3%-60% vinyl acetate
Humectant/plasticizer	PVP/vinyl acetate
PVP/VA ratio	Approximately 60:40
Fatty lactate	Lauryl lactate
Lower alkyl lactate	Ethyl lactate
Other enhancers	DMSO and capric acid
Preferred ratio	Approximately 4:1:1:0.8
Matrix thickness	10-300 microns
Maximum patch area	12.5 cm²

The claim language is internally notable because it refers to the PVP/vinyl acetate mixture as a humectant/plasticizer while separately claiming a polyacrylate adhesive copolymer. The classification of a particular excipient can affect both literal infringement and claim construction.

Does the patent cover Twirla or Xulane?

The patent's hormone combination is closer to a levonorgestrel/ethinyl estradiol product such as Twirla than to Xulane.

Twirla is a levonorgestrel/ethinyl estradiol transdermal system approved by the FDA under NDA 022684. The FDA label describes delivery of levonorgestrel and ethinyl estradiol through a transdermal patch and specifies a weekly application regimen during three weeks of each cycle (U.S. Food and Drug Administration, 2020).

Xulane contains norelgestromin and ethinyl estradiol, not levonorgestrel. Accordingly, Xulane would not satisfy claims expressly limited to levonorgestrel, although claim 1 itself recites a broader “progestin hormone” and could require separate analysis of the remaining matrix and enhancer limitations.

A product comparison cannot be resolved from active ingredients alone. The decisive evidence would include the patch's confidential composition, manufacturing specifications, enhancer concentrations, adhesive chemistry, and product instructions.

What is the FDA and Orange Book status?

Twirla received FDA approval in December 2020 under NDA 022684 for use as a contraceptive patch (FDA, 2020). Because it is a small-molecule drug product, the relevant abbreviated approval pathway is generally an ANDA under section 505(j), not the biosimilar pathway under section 351(k).

The Orange Book analysis should distinguish among:

FDA marketing approval.
Listed patents for the reference product.
Patent-term status.
Regulatory exclusivity.
Paragraph IV certifications.
Later continuation or improvement patents.

U.S. Patent 7,045,145 should not be treated as an automatically enforceable current Orange Book barrier merely because it relates technically to the product category. A patent must be listed for the relevant NDA, remain legally enforceable, and have claims that cover the relevant product or approved method.

The original patent's ordinary term was tied to its earliest effective nonprovisional filing date. The patent was granted in 2006, but the grant date does not control the ordinary expiration date for a post-June 1995 U.S. utility patent. Patent-term adjustment shown in the official patent record must be included in a final expiration calculation (U.S. Patent and Trademark Office, n.d.-a).

When did U.S. Patent 7,045,145 lose exclusivity?

The patent's nominal 20-year term appears to have ended in 2021 based on the earliest filing chronology associated with the patent. The legally operative date depends on the USPTO patent-term-adjustment calculation.

Event	Date or period
Earliest claimed priority	2000-era priority date
U.S. nonprovisional filing	2001-era filing
Patent grant	May 16, 2006
Nominal 20-year expiration	2021, based on the earliest effective nonprovisional filing
Possible adjustment	Must be taken from the USPTO patent record
PTE	No established basis identified from the supplied claims

Even if the patent received patent-term adjustment, any extension would need to be confirmed from the official patent record. Patent-term extension for regulatory review is distinct from patent-term adjustment and cannot be inferred from FDA approval alone.

The patent should therefore be analyzed as an expired or substantially aged patent for current freedom-to-operate purposes, while related continuation patents and later formulation patents may remain relevant.

What Paragraph IV challenges and generic entry risks exist?

A generic applicant seeking approval for a levonorgestrel/ethinyl estradiol transdermal system could address the patent through several routes:

Paragraph IV certification that the patent is invalid or will not be infringed.
Paragraph III certification if the patent is treated as unexpired.
A product design that omits one or more required enhancer ingredients.
A noninfringing adhesive system.
A different hormone combination.
A different patch size, matrix thickness, or dosage regimen.
A non-equivalent enhancer ratio.

A Paragraph IV notice can trigger Hatch-Waxman litigation and a 30-month stay of approval when the statutory conditions are met. That stay does not itself establish patent validity or infringement.

Because U.S. Patent 7,045,145 is an older patent, its practical importance to a current ANDA dispute would depend heavily on whether it remains unexpired and listed for the relevant reference product. Later patents may present the more significant launch risk.

Which companies are relevant to the competitive landscape?

The relevant market participants include:

Company	Relevance
Agile Therapeutics	Developer and commercial sponsor associated with Twirla
Corium, Inc.	Transdermal drug-delivery technology participant associated with the underlying platform and licensing history
FDA	Approval, labeling, exclusivity, and Orange Book authority
Generic manufacturers	Potential ANDA applicants for levonorgestrel/ethinyl estradiol patches
Janssen or related commercial entities	Relevant to competing norelgestromin/ethinyl estradiol patch products such as Xulane

The commercial distinction is important. Twirla and Xulane are both contraceptive patches, but they use different progestins. A patent claim directed to levonorgestrel does not automatically block a norelgestromin product.

What licensing deals affect the patent landscape?

The relevant transdermal technology was commercialized through relationships involving Agile and Corium. Public company disclosures have described licensing and development arrangements concerning transdermal delivery technology used in the contraceptive patch program.

The commercial effect of a license depends on:

Whether the license covers U.S. Patent 7,045,145 specifically.
Whether it includes continuations and divisionals.
Whether it grants rights to improvements.
Whether it is exclusive by field or territory.
Whether sublicensing rights exist.
Whether royalties survive patent expiration through know-how or technology-license provisions.

Patent ownership and commercial licensing are separate issues. A patent may expire while confidential manufacturing know-how, process rights, trademarks, or later patents remain commercially relevant.

What patent litigation affects U.S. Patent 7,045,145?

The supplied claim text does not establish a current infringement action, settlement, or Paragraph IV case involving U.S. Patent 7,045,145.

A litigation review should separate:

Cases involving the patent itself.
Cases involving related continuation patents.
Hatch-Waxman cases involving the Twirla NDA.
Inter partes review or post-grant proceedings.
Contract disputes over licensing or technology transfer.
Product-liability litigation, which does not necessarily determine patent validity.

A later patent in the same family may contain narrower but commercially stronger claims. A litigation search limited to patent number 7,045,145 could therefore understate the relevant patent risk.

What manufacturing and intellectual-property barriers remain?

The patent's manufacturing relevance is concentrated in the matrix and enhancer system. A party designing around the patent would likely focus on:

Replacing DMSO.
Replacing lauryl lactate or ethyl lactate.
Omitting capric acid.
Altering the enhancer ratio.
Using a different adhesive polymer.
Changing the matrix thickness.
Using a reservoir system instead of an adhesive matrix.
Selecting a different hormone salt, ester, or progestin.
Changing the weekly dosing regimen.

A design-around must be assessed against every claim element, including dependent claims and the doctrine of equivalents. Manufacturing know-how may remain difficult to replicate even when the patent has expired, particularly for coating uniformity, crystallization control, adhesion, drug stability, release rate, and scale-up.

How does this patent compare with later contraceptive-patch patents?

Issue	U.S. 7,045,145	Later product-specific patents
Primary focus	Broad transdermal matrix and enhancer combination	Commercial formulation, product performance, manufacturing, or approved product
Hormones	Broad in claim 1; LNG and estrogen in dependent claims	Often tied to a specific commercial product
Enhancers	Highly specific four-component combination	May use different excipients or process limitations
Use regimen	Weekly replacement for three of four weeks	May claim product labeling or pharmacokinetic parameters
Current term	Nominally expired or near expiration based on original filing	Later patents may remain in force
Generic risk	Mainly formulation and method risk	Potentially stronger current ANDA barrier
Biosimilar relevance	None	None for small-molecule contraceptive patches

The commercial patent landscape should therefore be evaluated as a family and product portfolio, not by this patent number alone.

Key Takeaways

U.S. Patent 7,045,145 claims a transdermal contraceptive matrix, not every hormonal contraceptive patch.
The critical limitation is the DMSO/lactate/capric-acid enhancer mixture and its specified ratio.
Claims 2-17 narrow the invention to levonorgestrel, ethinyl estradiol or 17 beta-estradiol, polyacrylate adhesives, PVP/VA, lauryl lactate, ethyl lactate, delivery rates, blood levels, thickness, and patch area.
Claims 18-34 separately protect a weekly fertility-control method.
Twirla is technically closer to the patent than Xulane because Twirla uses levonorgestrel and ethinyl estradiol, while Xulane uses norelgestromin and ethinyl estradiol.
The patent's nominal term appears to have ended in 2021, subject to USPTO patent-term adjustment.
Current launch risk is more likely to arise from later continuation, formulation, manufacturing, or product-specific patents than from the original patent alone.
Biosimilar law is not relevant. Any generic challenge would generally proceed through the ANDA and Paragraph IV framework.
A valid freedom-to-operate opinion requires review of the complete patent family, USPTO term data, Orange Book listings, product composition, prosecution history, and current litigation docket.

Frequently Asked Questions

Does U.S. Patent 7,045,145 cover all birth-control patches?

No. It covers patches containing the claimed adhesive matrix, hormone combination, and specified enhancer system. A patch using different hormones, enhancers, adhesive chemistry, or dosage architecture may fall outside the claims.

Is a levonorgestrel/ethinyl estradiol patch automatically infringing?

No. The hormones are only part of the claim. The product must also satisfy the matrix, adhesive, enhancer, ratio, and, for narrower claims, delivery-rate and physical-dimension limitations.

Is U.S. Patent 7,045,145 a biosimilar patent?

No. Levonorgestrel and ethinyl estradiol are small-molecule active ingredients. The relevant regulatory pathway for a competing product is generally an ANDA, not a biosimilar application.

Can a generic avoid the patent by changing the DMSO concentration?

Possibly, but concentration alone may not be sufficient. The generic would need to fall outside the claimed enhancer composition and ratio, while also avoiding infringement under any applicable equivalents theory and later related patents.

Does patent expiration eliminate all Twirla launch risk?

No. Expiration of this patent does not eliminate later patents, regulatory exclusivity, trade secrets, manufacturing know-how, trademarks, licensing restrictions, or litigation involving other patents.

References

U.S. Food and Drug Administration. (2020). Twirla (levonorgestrel and ethinyl estradiol) transdermal system: Prescribing information. FDA.
U.S. Patent and Trademark Office. (n.d.-a). Patent term adjustment. USPTO.
U.S. Patent and Trademark Office. (n.d.-b). U.S. Patent No. 7,045,145, transdermal delivery system for contraception. USPTO.
U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations, commonly known as the Orange Book. FDA.
Agile Therapeutics, Inc. (2021). Annual report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934. U.S. Securities and Exchange Commission.

PCT Information
PCT Filed	November 22, 2000	PCT Application Number:	PCT/US00/32043
PCT Publication Date:	May 31, 2001	PCT Publication Number:	WO01/37770

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Argentina	030037	⤷ Start Trial
Austria	453374	⤷ Start Trial
Australia	1788301	⤷ Start Trial
Australia	2004253593	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 7,045,145

Summary for Patent: 7,045,145