United States Drug Patent 5,082,668: Claim Scope, Expiration, Orange Book Status, and Patent Landscape

U.S. Patent No. 5,082,668 protects an osmotic drug-delivery device rather than a particular active pharmaceutical ingredient. Its claims require a semipermeable wall, a drug compartment containing 10% to 90% osmopolymer, a swellable push composition, and one or more exit passages that deliver the drug composition as a substantially continuous ribbon. The patent issued on January 21, 1992, and its ordinary 17-year term expired on January 21, 2009. It therefore presents no current U.S. blocking right or Paragraph IV risk.

What technology does U.S. Patent 5,082,668 protect?

The patent covers a multilayer osmotic delivery system. Fluid from the external environment crosses a semipermeable wall. The fluid hydrates or swells the push composition, which expands and displaces the drug composition through an exit orifice.

The claimed architecture has five central elements:

Required element	Claim function
Semipermeable wall	Permits fluid ingress while substantially restricting drug passage
Drug compartment	Holds the beneficial agent composition
Osmopolymer-containing drug composition	Contains 10% to 90% osmopolymer by the claim language
Push composition	Expands after absorbing fluid and forces the drug composition outward
Exit orifice or passageway	Delivers the drug composition at a controlled rate

The patent is directed to controlled delivery by osmotic pressure and swelling, not to a particular therapeutic use. The active ingredient can vary, provided the accused device satisfies the structural and functional limitations.

What is the core inventive concept?

The core concept is coordination between two fluid-responsive compositions:

The drug composition absorbs fluid and is discharged substantially as a ribbon.
The push composition absorbs fluid, expands, and supplies the displacement force.
The semipermeable wall regulates water entry.
The exit passage controls drug-composition release.

The claims are narrower than a generic claim to an osmotic tablet. They require the drug layer itself to include a substantial quantity of osmopolymer, stated as 10% to 90%, and require interaction between the drug layer, push layer, wall, and exit passage.

How do claims 1, 2, and 3 differ?

Claims 1 through 3 protect related implementations of the same device platform. Their principal differences concern the way delivery and fluid influx are defined.

Claim	Main limitation	Scope characteristic
Claim 1	Drug composition contains beneficial agent and 10% to 90% osmopolymer; delivery is substantially as a ribbon; delivery rate is expressed through agent-composition parameters	Rate-oriented claim
Claim 2	Drug composition contains 10% to 90% osmopolymer and an osmagent; drug and push compositions have defined fluid-influx behavior	Comparative influx claim
Claim 3	Drug composition contains 10% to 90% fluid-absorbing material; drug and push compositions are tied to specified absorption and displacement rates	Functional rate-and-density claim

What does “substantially as a ribbon” require?

The phrase indicates that the expelled drug composition should leave the device as a coherent, elongated mass rather than as isolated particles, a dissolved plume, or a freely dispersing suspension.

The limitation is important because the claim is not directed merely to release of drug through a hole. The delivery mode must involve extrusion of the drug composition in a ribbon-like form. The patent’s specification and technical examples would be relevant to determining how much variation is covered by “substantially.”

A device that delivers only dissolved drug through an orifice may avoid the ribbon limitation, depending on the formulation and the manner of delivery. A device that extrudes a hydrated polymer-drug mass is more likely to fall within the claim scope.

What does the 10% to 90% osmopolymer range cover?

The range is a substantial compositional limitation. A formulation with less than 10% osmopolymer or more than 90% osmopolymer would not literally satisfy that limitation.

The analysis depends on:

Whether the percentage is measured by weight or another basis defined in the specification.
Whether the osmopolymer is present in the drug composition, rather than only in the push layer.
Whether multiple osmopolymers are aggregated for purposes of the percentage.
Whether a formulation outside the range could raise a doctrine-of-equivalents issue.

The presence of an osmopolymer solely in the push composition is not enough for literal infringement of the claims quoted by the user. The drug composition itself must contain the required osmopolymer or fluid-absorbing material.

What construction does the patent require?

The claims should be read as combination claims. Each required element must be present in the same device.

A potentially infringing product generally would need all of the following:

A wall that permits fluid ingress.
A wall that substantially restricts passage of the drug or drug composition.
A compartment enclosed by that wall.
A drug composition containing the specified osmopolymer or fluid-absorbing component.
A push composition in contact with the drug composition.
Fluid-induced expansion or absorption by the push composition.
At least one exit orifice or passageway.
Delivery of the drug composition in the required ribbon or rate-controlled manner.

A conventional matrix tablet, diffusion-controlled patch, reservoir patch, implant, or ordinary liquid pump would not ordinarily satisfy the claims without the claimed osmotic architecture.

Is the patent directed to a drug substance?

No. The patent does not claim a specific active ingredient. Its subject matter is a drug-delivery device and the interaction of its formulation and mechanical elements.

The patent therefore differs from:

Compound patents, which claim the active molecule.
Salt or polymorph patents, which claim a chemical form.
Formulation patents, which claim a drug composition independent of a delivery device.
Method-of-use patents, which claim treatment of a disease.
Manufacturing patents, which claim production processes.

A product can be outside the scope of the '668 patent while remaining subject to other patents covering the active ingredient, formulation, dosage regimen, device manufacturing process, or commercial product.

When did U.S. Patent 5,082,668 lose exclusivity?

The patent issued on January 21, 1992. For a pre-June 8, 1995 application, the ordinary U.S. term was 17 years from the grant date under the then-applicable patent-term rule. On that basis, the patent expired on January 21, 2009. The statutory framework is reflected in the pre-1995 patent term rules and 35 U.S.C. § 154 as amended by the Uruguay Round Agreements Act (U.S. Patent and Trademark Office, n.d.-a; U.S. Congress, 2024).

Event	Date or status
Patent issued	January 21, 1992
Ordinary patent term	17 years from issuance
Expected expiration	January 21, 2009
Current enforceability	None in the United States
Patent-term extension under Hatch-Waxman	Not relevant to the expired device patent
Current Paragraph IV exposure	None under this patent

No current license is required to practice the expired claims in the United States. Separate rights may still exist in related continuation patents, foreign family members, or later patents covering a specific product implementation.

What is the Orange Book status of U.S. Patent 5,082,668?

U.S. Patent No. 5,082,668 is not itself an Orange Book drug patent listing. The FDA Orange Book identifies patents submitted by an NDA holder for an approved drug product. It does not function as a general registry of every expired device patent that may have been used in a commercial dosage form (FDA, 2024).

The patent has no current Orange Book blocking effect because:

It is expired.
It does not claim a specific approved active ingredient.
It is not a current compound, formulation, or method-of-use patent for an NDA product.
An ANDA applicant cannot be required to make a Paragraph IV certification against an expired patent.

An osmotic product may still have Orange Book listings for other patents. Those listings must be evaluated by product and NDA, not inferred from the '668 patent.

Does the patent create a Paragraph IV challenge risk?

No. A Paragraph IV certification addresses a listed patent that is unexpired or otherwise relevant to the ANDA product. Because the '668 patent expired in 2009, it cannot support a current patent-based stay of FDA approval under Hatch-Waxman.

A generic applicant developing an osmotic dosage form must still assess:

Current Orange Book-listed patents for the reference drug.
Later patents covering the commercial formulation.
Device patents owned by the innovator or a licensed technology provider.
Manufacturing-process patents.
Patent rights in jurisdictions where the product will be sold.

What patent landscape surrounds the '668 patent?

The '668 patent belongs to the broader Alza osmotic-delivery patent platform. Alza developed and commercialized OROS-type systems for controlled oral delivery. The surrounding landscape includes earlier foundational osmotic-device patents, later improvements, product-specific patents, and patents directed to manufacturing and formulation details.

Foundational osmotic-device patents

Representative U.S. patents in the broader technology area include:

Patent	General subject matter
U.S. Patent No. 4,612,008	Osmotic device with a semipermeable wall, drug compartment, push compartment, and delivery passage
U.S. Patent No. 5,082,668	Drug composition containing substantial osmopolymer and ribbon-like delivery
U.S. Patent No. 5,156,850	Controlled-release osmotic dosage forms and related device structures
U.S. Patent No. 5,413,572	Later osmotic delivery-system improvements
U.S. Patent No. 6,110,498	Later controlled-delivery and osmotic-device configurations

These patents should not be treated as a single active estate. Their terms, continuations, terminal disclaimers, claim scope, and expiration dates differ. The '668 patent is expired, while later family members may have had materially later expiration dates.

Commercial products associated with OROS technology

OROS-type technology has been used in products including controlled-release formulations of:

Methylphenidate, including Concerta.
Nifedipine, including Procardia XL.
Glipizide, including Glucotrol XL.
Oxybutynin, including Ditropan XL.
Verapamil, including Covera-HS.

The presence of an OROS-type device in a product does not establish that the product was covered specifically by U.S. Patent No. 5,082,668. Commercial products generally rely on a layered portfolio covering the active ingredient, formulation, dosage form, device geometry, manufacturing process, and method of use.

What formulation patents are distinct from the '668 patent?

Formulation patents can create more relevant commercial barriers than the expired device patent. They may claim:

The drug-to-polymer ratio.
Osmagent concentration.
Push-layer composition.
Membrane composition and thickness.
Orifice diameter or placement.
Drug-layer density.
Coating processes.
Overcoats or enteric layers.
Release profiles.
Specific dosing regimens.
Combination products.

A generic developer may avoid the '668 patent but still encounter a later patent claiming a particular osmotic tablet composition or manufacturing process. This distinction is material in an ANDA strategy because the relevant patent risk is product-specific, not determined solely by the existence of an expired platform patent.

What manufacturing barriers can remain after the patent expires?

The expired patent does not eliminate technical barriers. An alternative manufacturer may still need to solve:

Uniform drilling of the delivery orifice.
Layer compression and adhesion.
Control of membrane permeability.
Consistent push-layer expansion.
Drug-layer extrusion behavior.
Stability of high-polymer compositions.
Bioequivalence of the release profile.
Scale-up of multilayer tablet production.

Those are engineering and regulatory barriers, not continuing legal rights under the '668 patent.

How strong was the patent estate, and how strong is it now?

The original estate was technically significant because it claimed the interaction of formulation, fluid influx, swelling, and controlled extrusion. It did not depend on a narrow active ingredient, which gave it broad platform relevance across multiple drug products.

Its current legal strength is zero because the patent has expired. The practical assessment is:

Factor	Assessment
Technical breadth	Broad within the claimed osmotic ribbon-extrusion architecture
Active-ingredient coverage	None
Product-specific coverage	None in the claims quoted
Orange Book value today	None
Current enforcement value	None
Relevance to freedom-to-operate	Historical and technical only
Relevance to generic launch	No direct blocking effect
Relevance to later patents	Useful as prior art and technology background

The patent may remain relevant in validity analysis for later patents. Its disclosure and claims can be cited as prior art against later applications that attempt to claim similar osmotic structures or fluid-responsive drug layers. It may also affect the interpretation of what was known in the field before later patent filing dates.

Which companies are likely to matter in the competitive landscape?

The relevant commercial participants have included:

Alza Corporation, the principal historical developer of OROS technology.
Johnson & Johnson entities following Alza's acquisition.
Innovator pharmaceutical companies licensing or using osmotic systems.
Generic manufacturers producing controlled-release products.
Contract manufacturers with multilayer tablet and laser-drilling capabilities.

The commercial competition is usually determined by product-specific patents and FDA bioequivalence requirements, not by the expired '668 patent. A generic company with the technical ability to manufacture an osmotic dosage form may still need a noninfringement or invalidity position against later patents tied to the reference product.

What litigation and settlement issues affect the patent?

U.S. Patent No. 5,082,668 cannot support a new infringement action because it expired in 2009. Any historical litigation involving an OROS product must be separated from current rights under the patent.

Current diligence should distinguish among:

Litigation filed before expiration.
Disputes involving related continuation patents.
Product-specific Orange Book patents.
Trade-secret or manufacturing disputes.
Foreign litigation based on unexpired national patents.
Settlements that may have included licenses to separate patents.

An historical settlement involving an OROS product would not revive the expired U.S. patent. It could still contain contractual restrictions or licenses concerning other patents, trademarks, know-how, or manufacturing information.

How does the '668 patent compare with compound and biologic patents?

The '668 patent has a fundamentally different risk profile from a small-molecule or biologic patent.

Patent type	Primary protection	Typical launch risk after patent expiration
'668 device patent	Osmotic delivery architecture	No current U.S. blocking risk
Small-molecule compound patent	Active pharmaceutical ingredient	Generic entry usually depends on compound expiry
Formulation patent	Composition or dosage form	May delay or shape ANDA launch
Method-of-use patent	Treatment indication	Can require a skinny-label strategy
Biologic patent	Biologic molecule, formulation, or use	Biosimilar litigation under the BPCIA
Manufacturing patent	Production method	Can affect supply-chain and process design

The '668 patent has no biosimilar relevance. Biosimilars address biological products under the Public Health Service Act. The patent is relevant to oral controlled-release drug products and generic-device/formulation development, not to biologic interchangeability.

Key Takeaways

U.S. Patent No. 5,082,668 covers an osmotic delivery device, not a specific drug.
The claims require a semipermeable wall, drug composition, 10% to 90% osmopolymer or equivalent fluid-absorbing component, push composition, and exit passage.
Claims 1 through 3 differ mainly in their delivery-rate, fluid-influx, and absorption-rate limitations.
The “substantially as a ribbon” limitation narrows the claims to extrusion-like delivery of the drug composition.
The patent issued January 21, 1992, and expired January 21, 2009, under the ordinary pre-1995 17-year term.
It has no current Paragraph IV, Orange Book, or U.S. infringement significance.
Later formulation, device, manufacturing, and method-of-use patents may still affect specific osmotic products.
The patent remains relevant as historical technology and potential prior art against later patent claims.
It has no biosimilar relevance and does not protect an active ingredient, biologic, therapeutic indication, or commercial drug product by itself.

FAQs

Can a generic manufacturer use the osmotic technology disclosed in U.S. Patent 5,082,668?

Yes. The U.S. patent expired in 2009. A generic manufacturer must still evaluate unexpired patents covering the target reference product.

Does the patent cover Concerta or other OROS products directly?

No drug product is claimed by the quoted claims. Products such as Concerta may have used related OROS technology, but coverage depends on separate product, formulation, and device patents.

Can the expired patent be asserted against a product launched today?

No. An expired U.S. patent cannot support a new infringement claim for post-expiration activity.

Does the 10% to 90% range apply to the entire tablet?

The language applies to the beneficial agent composition, not necessarily to the complete tablet. The specification and claim construction determine the applicable measurement basis.

Can a device avoid the claims by using a liquid drug formulation?

Potentially, if it lacks the required solid or ribbon-like drug composition and does not satisfy the osmopolymer and functional delivery limitations. The complete device must be analyzed element by element.

References

Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: The Orange Book. U.S. Department of Health and Human Services. https://www.fda.gov/drugs/drug-approvals-and-databases/approved-drug-products-therapeutic-equivalence-evaluations-orange-book
United States Congress. (2024). 35 U.S.C. § 154: Contents and term of patent; provisional rights. https://uscode.house.gov/view.xhtml?req=granuleid:USC-prelim-title35-section154
United States Patent and Trademark Office. (n.d.-a). Patent term calculator and patent term adjustment information. https://www.uspto.gov/patents/laws/patent-term-calculator
United States Patent and Trademark Office. (n.d.-b). Patent Center. https://patentcenter.uspto.gov/
U.S. Patent No. 5,082,668. (1992). Osmotic device for delivering a beneficial agent. United States Patent and Trademark Office.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
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Details for Patent: 5,082,668

Summary for Patent: 5,082,668