US Patent 4,867,982: Scope, Claims, Expiration and Testosterone Patch Patent Landscape

US Patent 4,867,982 protected an early scrotal and genital testosterone transdermal delivery system associated with ALZA Corporation. Its strongest protection was directed to a specific flexible polymeric reservoir, non-elastically deformable fibrous backing, tack range, mechanical properties, testosterone loading, and daily genital or scrotal administration. The patent issued September 19, 1989, and its ordinary 17-year term expired September 19, 2006. It is no longer an enforceable patent in the United States.

The patent remains commercially relevant because its claim structure helped define the technical architecture of early testosterone patches, including the system later commercialized as Androderm. It does not create a current blocking right against generic testosterone products, although its disclosure may remain relevant as prior art in validity and freedom-to-operate analyses.

What patent is US 4,867,982?

US 4,867,982 covers a testosterone-releasing transdermal device intended for application to sensitive male genital locations, particularly the scrotum. The claims combine device construction with treatment methods.

Item	Information
U.S. patent	4,867,982
Technology	Transdermal testosterone delivery
Principal use	Testosterone replacement in hypogonadal males
Administration site	Male genitalia, especially the scrotum
Device type	Testosterone-containing polymeric matrix or reservoir
Key polymer	Ethylene/vinyl acetate copolymer
Claimed vinyl acetate range	40% to 60%
Preferred polymer embodiments	Approximately 40% or 51% vinyl acetate
Testosterone loading	Up to approximately 2.5%; dependent claims specify 5-15 mg total loading
Backing	Fibrous reinforcing material, including spun-bonded fabric
Adhesion mechanism	Non-adhesive clinging through tack and mechanical conformity
Administration period	At least approximately eight hours
Replacement cycle	Daily replacement, including use for up to approximately 24 hours
Issue date	September 19, 1989
Patent term	Approximately 17 years from issue under pre-1995 U.S. patent-term rules
Expiration	September 19, 2006
Current enforceability	Expired

The patent is a pre-Uruguay Round patent. For patents subject to the former rule, the term generally ran 17 years from grant rather than 20 years from the earliest effective nonprovisional filing date (35 U.S.C. § 154, historical version).

What technical problem does US 4,867,982 address?

The patent addresses delivery of testosterone through intact skin at body locations where conventional adhesive patches may be uncomfortable, poorly tolerated, or difficult to maintain.

The claimed device is designed to:

Conform to irregular and mobile genital skin.
Remain in contact without conventional pressure-sensitive adhesive.
Deliver testosterone through intact skin.
Maintain contact for at least eight hours.
Permit daily replacement.
Support testosterone absorption from the scrotum.
Produce testosterone blood levels that approximate the normal male circadian pattern.

The claim set combines material science, device mechanics, drug formulation, placement, duration, and therapeutic outcome. That combination narrows the principal apparatus claim while creating broader method-of-use claims.

What are the key limitations of claim 1?

Claim 1 is the central apparatus claim. It requires every limitation below.

Device geometry and mechanical properties

The device must be:

Flexible and compliant.
Between 2 and 10 mils thick.
Characterized by an extension modulus at 15% elongation of 1,000 to 15,000 gm/cm² in at least one direction.
Characterized by stress decay at 15% elongation after five minutes of 25% to 45%.
A 2 cm-wide strip must require 30 to 300 grams of force to produce 15% elongation.

These numerical limitations are important. A competing patch could avoid literal infringement by using a material outside one or more ranges, provided the difference is legally meaningful and the doctrine of equivalents does not apply.

Testosterone reservoir

The reservoir must contain testosterone dissolved in an ethylene/vinyl acetate copolymer having:

40% to 60% vinyl acetate content; and
A body-contacting surface through which testosterone is released to the skin.

The claim does not cover every testosterone-containing polymer matrix. It specifically requires the claimed ethylene/vinyl acetate composition and vinyl acetate range.

Tack limitation

The body-contacting surface must have tack of approximately 100 to 300 g/cm² at 35°C.

This is a functional material limitation. Temperature is material because tack can vary substantially with temperature and polymer composition. A product specification, laboratory test, or expert reconstruction would be required to determine whether a commercial patch falls inside the claimed range.

Fibrous reinforcement

The device must contain fibrous reinforcing material:

Embedded in the reservoir;
Not extending through the body-contacting surface;
Not fully submerged in the reservoir;
Forming the body-distal surface;
Non-elastically deformable in at least one direction; and
Retaining a fibrous texture on the outside surface.

The reinforcement is not merely a backing layer placed on top of the reservoir. Claim 1 requires a specific spatial relationship in which the reinforcement is embedded to a defined depth and forms the external distal surface.

Non-adhesive clinging

The device must be capable of non-adhesively clinging to genital skin while remaining in testosterone-transmitting relationship with the skin.

This limitation distinguishes the claimed system from a conventional adhesive patch. It also creates potential claim-construction disputes over whether “non-adhesively clinging” excludes all adhesive materials or only conventional pressure-sensitive adhesive layers.

How do claims 2 through 12 narrow the device?

Claims 2 through 12 provide alternative polymer, backing, concentration, and loading embodiments.

Claims	Added limitation	Commercial or legal significance
2	EVA with approximately 51% vinyl acetate	Narrows the polymer composition to a preferred embodiment
3	Spun-bonded fabric weighing up to approximately 0.3 oz./sq. yd.	Narrows the reinforcement structure
4	Up to approximately 2.5% testosterone	Narrows drug concentration
5	Claim 2 polymer plus up to 2.5% testosterone	Preferred 51% vinyl acetate embodiment
6	No undissolved testosterone and 5-15 mg loading	Requires dissolved drug and specified total dose
7	Claim 3 backing plus no undissolved testosterone and 5-15 mg loading	Narrowest reinforcement/loading combination
8	EVA with approximately 40% vinyl acetate	Alternative preferred polymer composition
9	Claim 8 polymer plus spun-bonded fabric up to 0.3 oz./sq. yd.	Specific 40% EVA/fabric embodiment
10	Claim 8 polymer plus up to 2.5% testosterone	40% EVA concentration embodiment
11	Claim 9 polymer plus up to 2.5% testosterone	Combined polymer, fabric, and concentration limitations
12	Claim 9 plus no undissolved testosterone and 5-15 mg loading	Narrow 40% EVA embodiment with specified drug loading

Claims 6, 7 and 12 are particularly formulation-specific. They require the absence of undissolved testosterone, not merely the presence of testosterone. A product containing crystalline or otherwise undissolved testosterone would fall outside the literal scope of those claims, although it could still implicate claim 1 or another broader claim if all other limitations were met.

What method-of-use claims does US 4,867,982 contain?

Claims 13 through 39 cover testosterone replacement methods. They fall into four groups.

Genital and scrotal administration claims

Claims 13-24 require applying the claimed device to male genitalia or the scrotum for at least approximately eight hours. Several dependent claims require daily replacement or use for up to approximately 24 hours.

These claims are narrower than a general testosterone replacement claim because they require the patented device or a specified dependent embodiment.

Polymeric matrix method claims

Claims 25-27 require applying a testosterone-releasing delivery device comprising a testosterone-containing polymeric matrix to the genitalia or scrotum for at least eight hours.

These claims are broader in device description than claim 1 because they do not expressly recite every mechanical, tack, EVA, or fibrous-reinforcement limitation. Their scope depends heavily on claim construction and the patent’s written description and enablement support.

Non-elastic stretching and conformity claims

Claims 28-31 require:

A stretchable testosterone-releasing device;
Application by non-elastically stretching the device around the genitalia;
Conformity and clinging to the skin;
At least eight hours of testosterone transmission.

Dependent claims add scrotal administration and the 100-300 g/cm² tack range.

These claims focus on the application mechanism and physical behavior rather than a specific polymer chemistry.

Circadian testosterone claims

Claims 32 and 33 cover delivering testosterone at a varying rate over the administration period to approximate the circadian blood-level pattern of a normal male.

This is the most clinically functional claim group. In an infringement dispute, evidence could include product design, pharmacokinetic data, labeling, clinical protocols, and observed serum testosterone profiles.

Claims 34-39 add daily replacement to several method claims.

How broad is the enforceable scope of the patent?

The enforceable scope is zero because the patent expired in 2006. The historical claim scope, however, can be ranked as follows:

Claim group	Historical breadth	Principal limiting features
Claim 1	Moderate to narrow	Detailed mechanical properties, EVA composition, tack, fibrous reinforcement
Claims 2-12	Narrow	Specific EVA content, fabric, testosterone concentration, and loading
Claims 13-24	Narrow to moderate	Claim 1 device plus genital/scrotal use and duration
Claims 25-27	Moderate	Testosterone-containing polymeric matrix, genital/scrotal application
Claims 28-31	Moderate	Non-elastic stretching, conformity, clinging, tack
Claims 32-33	Potentially broader method concept	Circadian testosterone delivery requirement
Claims 34-39	Narrower dependent methods	Daily replacement added

The most commercially important distinction is between the detailed apparatus claims and the more generalized method claims. A patch using a different polymer, adhesive architecture, or mechanical design might have avoided claim 1 while still raising questions under claims 25-33 during the patent term.

When did US 4,867,982 lose exclusivity?

US 4,867,982 lost patent exclusivity on September 19, 2006, based on its issue date and the pre-1995 17-year patent term.

Event	Date or period
Patent issued	September 19, 1989
Ordinary patent term	17 years from issue
Expiration	September 19, 2006
Post-expiration status	Prior art; no ordinary enforcement right

The patent did not receive the modern 20-year term measured from the earliest effective filing date. Patent term adjustment was not generally available in the modern form for a patent of this vintage.

Patent expiration is separate from FDA regulatory exclusivity. Any New Drug Application exclusivity associated with a testosterone product would have been governed by the Food, Drug, and Cosmetic Act and would not extend this patent’s term.

What was the FDA and Orange Book status?

US 4,867,982 is not a current enforceable Orange Book patent. A patent issued in 1989 would have expired before the modern commercial generic challenges involving testosterone transdermal systems.

The relevant regulatory product category is testosterone transdermal systems approved under an NDA. Androderm, historically marketed by Watson Pharmaceuticals and later associated with Actavis and Allergan, was an FDA-approved testosterone patch. The product used transdermal delivery for testosterone replacement in males with deficient or absent endogenous testosterone.

The Orange Book distinguishes among:

Drug substance patents;
Drug product or formulation patents; and
Method-of-use patents.

Expired patents may remain historically listed in regulatory records, but they do not create a current FDA approval barrier after expiration. A generic applicant may address unexpired listed patents through a Paragraph IV certification, a Paragraph III certification, or a statement that the patent is not applicable, depending on the listing and product formulation.

FDA approval does not itself determine infringement. A generic testosterone patch could receive approval while facing patent litigation based on unexpired formulation, device, manufacturing, or use patents.

Which companies challenged testosterone patch exclusivity?

The principal commercial competitive field has included:

ALZA Corporation, as the original transdermal technology developer;
Watson Pharmaceuticals;
Actavis;
Allergan;
Generic testosterone transdermal system manufacturers;
Other testosterone replacement suppliers focused on gels, injections, buccal systems, nasal products, and oral formulations.

The major competitive challenge to a testosterone patch is not limited to identical patch products. Alternative dosage forms can avoid patch-specific patents while competing for the same testosterone-replacement patients.

A complete current list of Paragraph IV challengers and litigation matters cannot be reliably inferred from the claim text alone. The expired status of US 4,867,982 means that any current Paragraph IV dispute would concern later patents, not this patent.

What patent landscape surrounds testosterone transdermal systems?

The patent estate for testosterone patches generally divides into five technical groups.

Reservoir and matrix patents

These patents cover testosterone dissolved or dispersed in polymer matrices, including EVA-based reservoirs. US 4,867,982 is an early example with unusually detailed mechanical and tack requirements.

Adhesive and attachment patents

Later patents may cover pressure-sensitive adhesives, silicone adhesives, acrylic systems, skin-contact layers, release liners, and adhesion performance over prolonged wear.

The 4,867,982 claims are distinctive because they emphasize non-adhesive clinging and fibrous surface texture rather than a conventional adhesive layer.

Permeation and delivery-rate patents

These patents address:

Testosterone flux through skin;
Rate-controlling membranes;
Permeation enhancers;
Serum concentration profiles;
Circadian delivery;
Reduction of skin irritation; and
Dose uniformity over the wear period.

Claims 32 and 33 are relevant to circadian delivery but expired with the patent.

Genital and scrotal administration patents

Scrotal skin can provide high testosterone permeability but may require special device compliance, retention, and irritation control. Patents may claim the administration site, wear duration, device geometry, or method of achieving a target serum concentration.

Manufacturing and process patents

Manufacturing barriers can include:

Uniform testosterone dissolution in EVA;
Controlled drug loading;
Lamination or embedding of fibrous reinforcement;
Thickness control in the 2-10 mil range;
Surface tack calibration;
Avoidance of undissolved testosterone; and
Cutting and packaging of thin flexible units.

These process rights may be more commercially important than the expired composition claims where later products use similar manufacturing steps.

Is US 4,867,982 relevant to biosimilar risk?

No. Biosimilar law applies to biological products, not conventional testosterone drug products. Testosterone is a small-molecule active pharmaceutical ingredient. Competitive products are generally regulated as generic drugs or alternative dosage forms, not biosimilars.

The relevant FDA pathways are abbreviated new drug applications for therapeutically equivalent generic products and, in some cases, 505(b)(2) applications for modified dosage forms or delivery systems.

What generic launch risks existed during the patent term?

Before expiration, a competing testosterone patch would have faced several potential risks:

Literal infringement of claim 1 through use of 40-60% EVA.
Infringement based on the claimed tack range.
Infringement based on fibrous reinforcement embedded in the reservoir.
Infringement of method claims through scrotal or genital administration.
Exposure under circadian delivery claims.
Regulatory delay from listed unexpired patents.
Litigation risk even where the competitor designed around one apparatus limitation.

After September 19, 2006, those risks ended for this patent. Current launch risk must be assessed against later patents, regulatory exclusivity, product labeling, and any applicable formulation or manufacturing rights.

How strong was the patent estate?

The patent was technically strong in its narrow core and weak as a long-term monopoly once its term expired.

Strengths

Clear focus on a difficult administration site.
Detailed physical-property limitations.
Specific EVA chemistry.
Defined non-adhesive retention mechanism.
Dependent claims covering preferred polymer and loading embodiments.
Method claims addressing genital, scrotal, daily, and circadian use.

Vulnerabilities

Many numerical limitations create design-around opportunities.
The fibrous reinforcement requirement is structurally specific.
Broad polymeric-matrix method claims could face anticipation or obviousness challenges.
Functional circadian claims may create proof issues.
The patent’s term ended before later waves of generic competition.
No current enforcement value remains.

What licensing and commercial rights were associated with the technology?

ALZA was a major transdermal drug-delivery company and licensed or commercialized delivery technologies through strategic pharmaceutical relationships. Testosterone patch commercialization later involved Watson Pharmaceuticals, which marketed Androderm in the United States.

The existence of a commercial license or product relationship does not extend the patent term. A license to an expired patent may retain contractual or historical significance but cannot ordinarily create a new patent exclusion right against independent market entrants.

No reliable conclusion about the continuing scope of any specific license agreement follows from US 4,867,982 alone.

Key Takeaways

US 4,867,982 covered a testosterone transdermal device for genital and scrotal administration.
Claim 1 required a narrow combination of EVA reservoir chemistry, mechanical properties, surface tack, embedded fibrous reinforcement, and non-adhesive clinging.
Claims 13-39 covered genital and scrotal testosterone replacement, daily replacement, non-elastic stretching, and circadian testosterone delivery.
The patent issued September 19, 1989, and expired September 19, 2006.
It is not a current blocking patent for generic testosterone products.
It is not relevant to biosimilar approval because testosterone is a small-molecule drug.
Current competitive risk depends on later patents covering formulations, adhesives, delivery rates, manufacturing processes, and alternative testosterone dosage forms.
The patent’s historical technical value is greater than its present legal value.

FAQs About US Patent 4,867,982

Did US Patent 4,867,982 cover Androderm?

It covered technology materially related to early testosterone transdermal patch systems, including the reservoir, flexible backing, non-adhesive clinging, and genital or scrotal use concepts associated with that product category. Product-specific infringement requires comparison with the issued claims and the actual product configuration.

Can an expired patent still affect a generic testosterone patch?

Yes, as prior art. It cannot support an infringement action after expiration, but it may affect novelty, obviousness, inventorship, validity, and freedom-to-operate analysis for later patents.

Did the patent claim all testosterone patches?

No. The main apparatus claim required specific EVA composition, mechanical ranges, tack, fibrous reinforcement, and non-adhesive clinging. A testosterone patch using a materially different architecture could fall outside the literal claim scope.

Are scrotal testosterone products subject to biosimilar regulation?

No. Testosterone products are generally regulated as small-molecule drugs. Generic or 505(b)(2) pathways, rather than biosimilar pathways, are relevant.

What later patents should be reviewed for testosterone patch launch risk?

A launch review should focus on unexpired patents covering testosterone concentration and loading, adhesive layers, permeation enhancers, patch geometry, release-rate control, circadian dosing, manufacturing processes, and FDA-listed methods of use.

References

United States Patent and Trademark Office. (1989). U.S. Patent No. 4,867,982.
United States Code, 35 U.S.C. § 154. Patent term.
United States Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations.
United States Food and Drug Administration. (2024). Orange Book: Approved drug products with therapeutic equivalence evaluations.
United States Code, 21 U.S.C. § 355. New drug applications and abbreviated applications.
United States Code, 42 U.S.C. § 262. Regulation of biological products.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Canada	1257819	⤷ Start Trial
Germany	3523065	⤷ Start Trial
Germany	3687067	⤷ Start Trial
European Patent Office	0232580	⤷ Start Trial
Spain	296615	⤷ Start Trial
Spain	556380	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Summary for Patent: 4,867,982