US Patent 5,876,746: Scope, Claim Construction, Expiration, and Transdermal Contraceptive Patent Landscape

US Patent 5,876,746 covers a seven-day, non-acrylate transdermal matrix patch containing 17-deacetyl norgestimate, also known as norelgestromin, with a polyisobutylene- or silicone-based pressure-sensitive adhesive. The strongest claim set is directed to a specific formulation architecture: norelgestromin, polyisobutylene, an aliphatic tackifier, optional crosslinked polyvinylpyrrolidone, and optional lauryl lactate or estrogen.

The patent issued on March 2, 1999. Its ordinary 20-year patent term ran from the relevant nonprovisional filing date and expired no later than the mid-2010s. Patent 5,876,746 is not a live exclusion against current generic or follow-on transdermal contraceptive development.

What technology does US Patent 5,876,746 protect?

The patent protects transdermal delivery of norelgestromin through a non-acrylate matrix patch. Its central technical limitations are:

Limitation	Role in the claimed invention
Backing layer	Supports and protects the drug-containing matrix
Non-acrylate matrix	Excludes acrylic pressure-sensitive adhesive systems
17-deacetyl norgestimate	Progestin active ingredient, commonly identified as norelgestromin
Polyisobutylene or silicone adhesive	Provides skin adhesion and forms the drug matrix
Aliphatic tackifier	Improves adhesion and matrix properties
Lauryl lactate	Skin permeation enhancer
Crosslinked polyvinylpyrrolidone	Optional matrix component in the narrower claims
Seven-day administration	Defines the sustained-delivery period in claims 22, 25, 27, 28 and 31-41
Estrogen	Optional co-delivered component, including ethinyl estradiol or 17-beta-estradiol

The claims are formulation and delivery-system claims. They do not broadly cover every use of norelgestromin, every contraceptive patch, or every estrogen-progestin combination.

What is the chemical scope of the patent?

“17-deacetyl norgestimate” is the principal progestin limitation. In commercial transdermal contraceptive products, this compound is generally referred to as norelgestromin, also known as 17-deacetyl norgestimate.

The patent does not claim norgestimate generically. A product using a different progestin, such as levonorgestrel, gestodene, desogestrel, drospirenone, or etonogestrel, would not satisfy the express norelgestromin limitation.

The estrogen claims cover two identified alternatives:

Ethinyl estradiol.
17-beta-estradiol.

The claims do not cover every estrogen by their literal language. A product using mestranol, estrone, estetrol, or another estrogen would require a separate infringement analysis under claim construction and, potentially, the doctrine of equivalents.

How broad is independent claim 1?

Claim 1 covers a transdermal patch comprising:

a backing layer; and
a non-acrylate matrix layer under the backing layer;
the matrix contains 17-deacetyl norgestimate;
the matrix contains lauryl lactate;
the adhesive contains at least one of silicone or polyisobutylene; and
the matrix delivers an ovulation-inhibiting amount through the skin.

Claim 1 is relatively broad within the non-acrylate formulation field because it does not require:

estrogen;
a specific daily dose;
a seven-day wear period;
crosslinked polyvinylpyrrolidone;
polybutene oil;
a particular patch area;
a particular backing material;
a particular manufacturing process.

A patch using silicone adhesive rather than polyisobutylene can fall within claim 1 if the other limitations are met. Claims 3 and 20 narrow the adhesive system toward polyisobutylene and aliphatic tackifier chemistry.

Which claims are the strongest formulation claims?

Claims 31 through 38 provide the most technically specific formulation coverage.

Claim 31

Claim 31 requires:

a backing layer;
a non-acrylate matrix;
17-deacetyl norgestimate;
crosslinked polyvinylpyrrolidone;
a pressure-sensitive adhesive consisting essentially of polyisobutylene and an aliphatic resin tackifier; and
seven-day transdermal administration.

This claim is narrower than claim 1 but gives the patent a more defined formulation target.

Claims 32 through 36

These claims narrow the product to:

ovulation prevention;
150 to 350 micrograms per day of norelgestromin;
polybutene oil as the tackifier; and
a skin-permeation enhancer, specifically lauryl lactate.

Claims 37 and 38

These claims add estrogen, with claim 38 specifically identifying ethinyl estradiol.

A commercial product containing the full combination of norelgestromin, ethinyl estradiol, crosslinked polyvinylpyrrolidone, polyisobutylene, aliphatic tackifier and lauryl lactate would map closely to the narrow formulation claims.

What dose and delivery period do the claims require?

The principal claimed norelgestromin delivery range is 150 to 350 micrograms per day.

The estrogen ranges appear in claims 6, 8 and 19:

Active ingredient	Claimed delivery range
Norelgestromin	150-350 micrograms/day
Ethinyl estradiol	10-35 micrograms/day
17-beta-estradiol	30-150 micrograms/day

Claims 22, 25, 27, 28 and 31-41 add a seven-consecutive-day administration period. The seven-day limitation is material. A patch designed for three, four, or five days would not literally satisfy a claim requiring administration for seven consecutive days, although other claims without that limitation could remain relevant.

The claims use both structural and functional language. “Adapted to be in diffusional communication with the skin” describes a matrix that permits drug migration into the skin. “Ovulation-inhibiting amount” and “therapeutically effective amount” are functional limitations tied to the intended pharmacologic result.

What is the scope of the estrogen-combination claims?

Claims 4-8, 14-19 and 23-25 cover patches and methods that co-administer norelgestromin with an estrogen.

The principal combination is:

norelgestromin;
ethinyl estradiol or 17-beta-estradiol;
lauryl lactate;
polyisobutylene;
an aliphatic tackifier; and
a non-acrylate matrix.

Claims 4 and 14 are important because they do not specify the same narrow daily dose ranges as claims 6, 8 and 19. A product may therefore fall within a broader combination claim even if its dose is outside the narrower ranges, provided it meets the remaining limitations.

The hormone replacement therapy claims are unusual commercially. A patch containing norelgestromin and estrogen would more naturally be developed for contraception than postmenopausal hormone replacement. The claims nevertheless create a separate method-of-use category for hormone therapy.

How should the dependent-claim errors be analyzed?

The supplied claim text contains apparent dependency and drafting inconsistencies.

Claim 11 refers to claim 7, which is a patch claim for 17-beta-estradiol. Claim 12 then states that “the estrogen is ethinyl estradiol,” which conflicts with the dependency structure unless claim 12 was intended to depend from another claim or the source contains a transcription error.

The text also contains typographical variations such as:

“17-deacteyl norgestimate”;
“17 deacetyl norgestimate”; and
“17-deacetyl norgestimate.”

These errors generally do not change the identity of the claimed active ingredient if the issued patent specification and prosecution history establish the intended compound. Claim dependency, however, can affect enforceability, claim construction and infringement analysis.

For a litigation-grade opinion, the issued patent, certificate of correction, prosecution history and any terminal disclaimer control over the reproduced text. The claim set supplied here is sufficient for technical scope analysis but not for a definitive validity opinion.

When did US Patent 5,876,746 lose exclusivity?

US Patent 5,876,746 issued on March 2, 1999. Its ordinary patent term expired in the mid-2010s based on the relevant filing date. The patent is therefore expired and does not currently block manufacture, sale or FDA approval of a norelgestromin transdermal patch.

The key consequence is that:

no current patent injunction can be based solely on an expired claim;
a Paragraph IV challenge to this patent would have no meaningful present-day commercial target;
expired claims remain relevant as prior art and as evidence of formulation disclosure;
later continuation, divisional or improvement patents must be analyzed separately.

Expiration does not eliminate regulatory exclusivity that may have existed during the patent term, but it eliminates the patent exclusion itself.

What was the patent’s relationship to Ortho Evra and Xulane?

The patent technology is closely associated with the transdermal contraceptive product category containing norelgestromin and ethinyl estradiol. Ortho Evra was the principal branded product associated with this delivery approach. Xulane later became a marketed norelgestromin/ethinyl estradiol transdermal system.

The commercial product must be separated from the patent claim scope:

Product or category	Relevance to US 5,876,746
Ortho Evra	Commercial norelgestromin/ethinyl estradiol patch category
Xulane	Later marketed norelgestromin/ethinyl estradiol patch
Norelgestromin generic patches	Potentially relevant to composition, dose and delivery-period claims
Acrylic adhesive patches	Potentially outside the non-acrylate limitations
Oral norgestimate products	Outside the transdermal patch claims
Levonorgestrel patches	Outside the express norelgestromin limitation

The patent alone does not establish ownership of commercial trademarks, regulatory applications or licensing agreements. Patent ownership, FDA sponsorship and marketing rights may have changed independently.

What was the Orange Book status of US Patent 5,876,746?

The Orange Book evaluates patents listed by the NDA holder for an approved drug product. A patent’s historical listing does not extend its enforceable term.

For norelgestromin/ethinyl estradiol transdermal systems, the relevant FDA issues include:

whether the patent was listed against the reference NDA;
whether the listed patent covered the drug substance, drug product or method of use;
the patent expiration date recorded by FDA;
whether generic applicants filed Paragraph III or Paragraph IV certifications; and
whether any 30-month stay or litigation event occurred before expiration.

Because US Patent 5,876,746 has expired, it is not a current Orange Book barrier to generic entry. Any historical Paragraph IV dispute involving this patent would be commercially moot after expiration unless it involved damages or an earlier launch.

FDA’s Approved Drug Products with Therapeutic Equivalence Evaluations remains the controlling source for current listing status and patent certifications.[2]

Were Paragraph IV challenges possible?

Yes. During the patent’s enforceable term, an ANDA applicant seeking approval for a therapeutically equivalent norelgestromin/ethinyl estradiol patch could have filed a Paragraph IV certification asserting that:

the patent was invalid;
the patent was unenforceable; or
the proposed product did not infringe.

A Paragraph IV certification could have triggered patent litigation under the Hatch-Waxman Act and, for an applicable listed patent, a 30-month stay of approval under 21 U.S.C. § 355(j)(5)(B)(iii).

After expiration, the commercial value of a Paragraph IV challenge falls sharply. A current applicant can rely on patent expiration rather than undertake a validity challenge to obtain approval.

What generic entry risks existed?

Before patent expiration, generic entry risk depended on the product’s adhesive and matrix design.

Higher-risk design

A product would have faced the greatest historical risk if it used:

norelgestromin;
ethinyl estradiol;
150-350 micrograms/day of norelgestromin;
10-35 micrograms/day of ethinyl estradiol;
a seven-day patch;
non-acrylate matrix technology;
polyisobutylene;
aliphatic tackifier;
polybutene oil; and
lauryl lactate.

That design would have tracked multiple claim limitations.

Lower-risk design

Risk would have been reduced by using:

an acrylic adhesive system;
a different progestin;
a different estrogen;
a delivery interval other than seven days;
a dose outside the claimed range;
a reservoir rather than a claimed matrix architecture;
no lauryl lactate where required by the asserted claim; or
a materially different adhesive chemistry.

A design-around would still require claim-by-claim analysis because claim 1 is broader than the narrower polyisobutylene and crosslinked-polyvinylpyrrolidone claims.

How strong was the patent estate?

The patent was technically meaningful but commercially narrow in several respects.

Strength factor	Assessment
Active ingredient specificity	Strong limitation to norelgestromin
Dosage form	Strong limitation to transdermal matrix patch
Adhesive chemistry	Provides meaningful differentiation from acrylic systems
Combination with estrogen	Relevant to commercial contraceptive products
Seven-day use	Narrows coverage but aligns with commercial patch practice
Manufacturing protection	Limited; claims focus on the finished patch and method of use
Broad contraceptive coverage	Limited by matrix, adhesive and active-ingredient requirements
Current enforceability	None after expiration
Design-around potential	Significant through adhesive, matrix, dose or wear-period changes

The claims are strongest against a close formulation copy. They are weaker against alternative transdermal systems that change the adhesive class or matrix structure.

What manufacturing and formulation barriers did the patent create?

The patent disclosed a formulation platform requiring simultaneous control of:

norelgestromin solubility;
skin flux;
adhesive tack;
seven-day wear;
matrix uniformity;
crystallization control;
dose loading;
estrogen compatibility; and
release stability.

Lauryl lactate and crosslinked polyvinylpyrrolidone are particularly relevant formulation variables. Lauryl lactate can increase skin permeation, while crosslinked polyvinylpyrrolidone can influence drug dispersion and matrix integrity.

These technical constraints can create development barriers even after patent expiration. A generic sponsor must demonstrate consistent drug content, adhesion, skin delivery, stability and bioequivalence or therapeutic equivalence under the applicable FDA pathway.

What licensing deals and litigation affected the patent?

The patent claims and bibliographic information do not, by themselves, establish a license agreement, royalty arrangement or settlement agreement. Commercial rights in the norelgestromin patch market involved separate patent, regulatory, manufacturing and marketing arrangements.

Any historical litigation assessment must distinguish:

lawsuits involving US 5,876,746;
lawsuits involving related continuation or improvement patents;
disputes over other Ortho Evra or Xulane patents;
patent-listing disputes;
product-liability litigation; and
commercial agreements unrelated to patent validity.

The expiration of US 5,876,746 means that any current litigation risk must come from later patents, trade secrets, regulatory exclusivity, product liability or contract rights rather than this patent alone.

How does US Patent 5,876,746 compare with competing transdermal contraceptive patents?

Patent strategy	Typical protection	Relationship to US 5,876,746
Active-ingredient patent	Norelgestromin or estrogen composition	May overlap chemically but not necessarily the patch structure
Acrylic matrix patent	Acrylic adhesive containing hormones	Potential design-around to the non-acrylate claims
Silicone matrix patent	Silicone adhesive delivery system	Covered by claim 1 if other limitations are met
Polyisobutylene matrix patent	Non-acrylate adhesive formulation	Closest technical overlap
Reservoir patch patent	Membrane-controlled delivery	Potentially outside matrix-only claims
Method-of-use patent	Contraception or hormone therapy	Could overlap with claims 9-19 and 39-41
Manufacturing patent	Coating, drying, lamination or packaging	Not broadly covered by the supplied claims

The principal competitive distinction is matrix chemistry. A manufacturer can reduce literal infringement exposure by selecting a formulation architecture outside the claimed non-acrylate polyisobutylene system, subject to other patents and the doctrine of equivalents.

What is the current commercial exposure?

The patent itself presents no current revenue exposure because it is expired. Historical exposure was concentrated in the branded norelgestromin/ethinyl estradiol patch market, particularly products using a seven-day transdermal matrix.

Current commercial exposure should instead be assessed against:

later formulation patents;
patents covering patch construction or release control;
FDA exclusivity;
manufacturing know-how;
supply agreements;
trademarks;
regulatory requirements for generic transdermal systems; and
product-liability claims.

A company entering the market today would not need a license to expired US Patent 5,876,746. It would need to clear the remaining patent estate and demonstrate FDA-compliant performance.

Key Takeaways

US Patent 5,876,746 covers a non-acrylate transdermal matrix patch containing norelgestromin.
Claim 1 requires norelgestromin, lauryl lactate and a silicone or polyisobutylene pressure-sensitive adhesive.
The narrower claims focus on polyisobutylene, aliphatic tackifier, crosslinked polyvinylpyrrolidone, polybutene oil and seven-day delivery.
Estrogen-combination claims cover ethinyl estradiol and 17-beta-estradiol.
The principal dose range is 150-350 micrograms/day of norelgestromin.
The patent is expired and is not a current blocking right.
The patent was most relevant to close copies of the Ortho Evra/Xulane-type formulation.
Acrylic systems, different hormones, different wear periods and alternative matrix designs provide potential design-around paths.
Current market entry risk must be evaluated against later patents and FDA requirements, not this expired patent alone.

FAQs

Does US Patent 5,876,746 cover all norelgestromin patches?

No. It requires a transdermal matrix architecture and, in the broadest independent claim supplied, lauryl lactate plus a non-acrylate adhesive containing silicone or polyisobutylene.

Is norelgestromin the same compound as 17-deacetyl norgestimate?

Yes. Norelgestromin is commonly identified as 17-deacetyl norgestimate, the progestin specified in the patent claims.

Can a patch using an acrylic adhesive avoid the patent?

Potentially. The claims expressly require a non-acrylate matrix, so an acrylic formulation may avoid literal infringement of those claims. Other patents and equivalents analysis remain separate issues.

Does the patent cover a three-day contraceptive patch?

The supplied claims requiring seven consecutive days would not literally cover a three-day patch. Claims without the seven-day limitation would require separate analysis.

Does the expired patent still need to be licensed for a generic patch?

No. An expired patent cannot impose a current license requirement. A generic sponsor must still clear later patents and satisfy FDA approval requirements.

References

United States Patent and Trademark Office. (1999). U.S. Patent No. 5,876,746: Transdermal contraceptive delivery system.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations.
U.S. Food and Drug Administration. (2024). Orange Book: Approved drug products with therapeutic equivalence evaluations.
21 U.S.C. § 355(j). Abbreviated new drug applications and patent certifications.
35 U.S.C. § 154. Contents and term of patents; priority and patent-term rules.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
European Patent Office	0836506	⤷ Start Trial	SPC/GB03/025	United Kingdom	⤷ Start Trial
Austria	229828	⤷ Start Trial
Australia	6259796	⤷ Start Trial
Australia	703593	⤷ Start Trial
Canada	2222133	⤷ Start Trial
China	1188189	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 5,876,746

Summary for Patent: 5,876,746