United States Patent 8,192,722: Claim Scope, Oxymorphone Abuse-Deterrent Technology, and Patent Landscape

U.S. Patent No. 8,192,722 covers high-strength, polyethylene-oxide-based dosage forms containing oxymorphone or related compounds. The independent claims target both the finished dosage form and its extrusion-based manufacturing process. The principal technical limitations are a breaking strength of at least 500 N, polyethylene oxide with a molecular weight of at least 0.5 million g/mol, and thermoforming by extrusion without discoloration.

The patent is closely associated with abuse-deterrent extended-release opioid technology, including the reformulated Opana ER product. Its commercial value rests on the combination of mechanical resistance, controlled release, extraction-resistant gel formation and manufacturing controls. The broadest claims are narrower than a generic “tamper-resistant opioid” concept because they require oxymorphone or a qualifying derivative and a specific high-molecular-weight polyethylene oxide system.

What does U.S. Patent 8,192,722 protect?

The patent protects two related categories:

An abuse-deterrent dosage form containing oxymorphone or an acceptable salt, solvate, ester, ether or amide.
A process for producing that dosage form through extrusion, singulation and forming operations.

The central product claim, claim 1, requires all of the following:

Claim element	Requirement
Dosage form	Abuse-proofed dosage form
Manufacturing characteristic	Thermoformed by extrusion
Appearance	No discoloration
Active ingredient	Oxymorphone or a physiologically acceptable compound or derivative
Polymer	Polyethylene oxide
Polymer molecular weight	At least 0.5 million g/mol
Mechanical property	Breaking strength of at least 500 N
Optional ingredients	Auxiliary substances and waxes

The claim does not cover every oxymorphone extended-release tablet. A competing product would need to satisfy the specific polymer, hardness and extrusion limitations, either literally or under an applicable doctrine of equivalents.

The patent was assigned to Grünenthal GmbH and belongs to the company’s broader abuse-deterrent dosage-form portfolio. The patent family was directed toward dosage forms that resist crushing, grinding, chewing, solvent extraction and other common manipulation methods. [1]

How broad is claim 1 of U.S. Patent 8,192,722?

Claim 1 is technically broad in its optional formulation language but narrow in its mandatory limitations.

The claim does not require a particular dose, tablet shape, release rate, wax concentration, antagonist, dye, emetic or irritant. It also does not require a specific polyethylene oxide grade, provided the polymer has a molecular weight of at least 0.5 million g/mol.

The claim is narrowed by four important limitations:

Oxymorphone limitation

The active ingredient must be oxymorphone or a physiologically acceptable compound or derivative. Claim 27 confirms that the covered derivatives include salts, solvates, esters, ethers and amides.

The claim therefore has potential relevance to:

Oxymorphone hydrochloride
Oxymorphone salts
Oxymorphone solvates
Oxymorphone prodrugs or derivatives that fall within the claim language
Oxymorphone products containing other active ingredients, if the oxymorphone limitation remains satisfied

The claim does not extend automatically to oxycodone, hydrocodone, morphine or buprenorphine. Those products would need to be assessed against other claims or related patent families.

Polyethylene oxide limitation

The formulation must contain polyethylene oxide with a molecular weight of at least 0.5 million g/mol. Claims 3 and 4 raise the threshold to at least 1 million g/mol and, in the narrowest dependent range, approximately 1 million to 15 million g/mol.

High-molecular-weight polyethylene oxide contributes viscosity, matrix integrity and resistance to mechanical size reduction. It can also form a viscous gel when exposed to aqueous media, reducing the ability to inject or rapidly extract the active ingredient.

Breaking-strength limitation

The dosage form must have a breaking strength of at least 500 N. This is a substantial mechanical-resistance requirement. Ordinary immediate-release tablets and many conventional extended-release tablets would not satisfy it.

The breaking-strength limitation creates a measurable infringement issue. A product may contain the same active ingredient and polymer but avoid claim 1 if its tested breaking strength is below the specified threshold. Testing methodology, tablet geometry, conditioning, storage and instrument calibration can become central in litigation.

Extrusion and thermoforming limitation

The dosage form must be thermoformed by extrusion. The process claims describe mixing, heating, extrusion, singulation and final forming. A tablet manufactured only by conventional direct compression may have difficulty satisfying the product claim if the extrusion limitation is construed as a product-by-process limitation requiring the claimed manufacturing history.

The practical scope depends on claim construction. If “thermoformed by extrusion” is treated as a product characteristic that produces identifiable structural properties, a non-extruded product may avoid the claim. If the phrase is treated as a process limitation applicable to the product, the manufacturing route becomes central.

What do claims 2 through 16 add?

Claims 2 through 16 create narrower formulation and dosage-form positions.

Claims	Protected subject matter
2	Tablet dosage form
3-4	Polyethylene oxide molecular weight of at least 1 million, including approximately 1-15 million
5-6	Wax with a softening point of at least 60°C; carnauba wax or beeswax
7-8	Irritant, viscosity-increasing agent, antagonist, emetic, dye or bitter substance
9-11	Controlled-release active ingredient and matrix incorporating polyethylene oxide or wax
12-14	Core and surrounding tubular domain with different morphology
15-16	Antioxidant excipients, including ascorbic acid, BHA, BHT, vitamin E, sodium bisulfite and alpha-tocopherol

Formulation patents and abuse-deterrent excipients

Claims 7 and 8 are particularly important for product-development analysis. They cover additional deterrence mechanisms that operate after manipulation:

Irritation of nasal passages or the pharynx
Gel formation after extraction into liquid
A visually distinguishable gel in a larger aqueous volume
Antagonism of the opioid
Emetic activity
Bitter taste
Dye-based detection

The viscosity-increasing-agent list is extensive. It includes xanthan gum, sodium alginate, pectins, guar flour, gellan gum, carrageenan, cellulose combinations, polyacrylic acid, sodium hyaluronate and other polysaccharide systems.

A formulation that uses a different polymer may avoid claim 8 but remain exposed to claim 7 if it performs the claimed viscosity-increasing function. Conversely, using polyethylene oxide alone may satisfy claim 1 without satisfying the additional limitations of claims 7 and 8.

Controlled-release claims

Claims 9 through 11 cover active ingredient present at least partly in controlled-release form, including a controlled-release matrix containing polyethylene oxide and/or wax.

These claims create a stronger position against extended-release products than against an immediate-release abuse-deterrent formulation. The claims do not specify a particular dissolution profile, dosing interval or release mechanism. A competing extended-release tablet could therefore face risk if its matrix uses the claimed high-molecular-weight polymer and meets the mechanical and extrusion limitations.

Core and tubular-domain claims

Claims 12 through 14 cover a dosage form with a core and a surrounding tubular domain having different morphology. The core and tubular domain may have substantially the same chemical composition, and the tubular domain may not completely cover the core.

These claims target internal structure rather than only ingredient identity. They may be relevant to co-extruded, partially coated or morphologically differentiated dosage forms. Because the claims permit substantially the same chemical composition, the distinction lies principally in morphology and spatial arrangement.

What do claims 17 through 26 protect?

Claims 17 through 26 cover the manufacturing process.

The required process includes:

Mixing active ingredient, polymer and optional excipients.
Heating the mixture in an extruder to at least the softening point of the polyethylene oxide.
Extruding the mixture through an outlet orifice.
Singulating and forming the plastic extrudate.
Optionally cooling, reheating, pelletizing or pressing the material into tablets.

The dependent process claims add the following limitations:

Twin-screw extrusion
Inert gas processing
Nitrogen atmosphere
Die with at least one bore
Cutting the extrudate
Counter-rotating calender rolls with opposing recesses
Pelletizing or tablet pressing
Press forming at a pressure of at least 1 kN
Press forming at a temperature 25°C to 40°C below the mixture’s melting range

Manufacturing and IP barriers

The process claims can create freedom-to-operate risk even where the finished product claims are avoided. A manufacturer using a twin-screw extruder, nitrogen atmosphere, die extrusion and tablet compression may practice several process limitations simultaneously.

The strongest process position is claim 17 because it captures the basic extrusion and forming sequence. Claims 18 through 26 provide narrower fallback positions. A design-around could involve:

Non-extrusion processing
A different polymer system
Compression of a dry blend without thermoforming
A polymer molecular weight below 0.5 million g/mol
A different active ingredient
A final product with breaking strength below 500 N

Each design-around carries formulation and regulatory consequences. Lowering hardness or removing polyethylene oxide may affect abuse-deterrent performance, dissolution, manufacturability and FDA labeling.

When did U.S. Patent 8,192,722 expire?

The patent issued on June 5, 2012. Its term is governed by the 20-year patent-term framework measured from the applicable earliest nonprovisional or international filing date, subject to patent-term adjustment, patent-term extension and terminal-disclaimer issues. The patent’s nominal term is associated with the October 2004 filing period and therefore places expiration in the 2024-2025 period, depending on the applicable term calculation and any recorded adjustment. [1][2]

For commercial diligence, the controlling source is the USPTO Patent Center transaction and patent-term data, not the issue date. A patent may remain listed in the Orange Book after the end of enforceability if the FDA listing has not yet been administratively removed. Patent expiration and Orange Book delisting are separate events.

What is the Orange Book status of U.S. Patent 8,192,722?

U.S. Patent 8,192,722 was associated with the oxymorphone extended-release product Opana ER and its abuse-deterrent reformulation. FDA Orange Book records should be checked by NDA and product presentation because listing status can differ between the original and reformulated products. [3]

The patent’s relevance to Opana ER arises from the overlap between the claimed technology and the product’s abuse-deterrent design:

Oxymorphone active ingredient
Extended-release matrix
High mechanical strength
Polyethylene oxide-based formulation technology
Resistance to crushing and extraction

FDA approved reformulated Opana ER in 2011 as an abuse-deterrent product. In 2017, FDA requested withdrawal of reformulated Opana ER after concluding that the product’s benefits no longer outweighed its risks in light of postmarketing reports involving injection abuse. [4] The withdrawal decision did not itself invalidate or cancel the patent claims.

Which companies challenged Opana ER patents?

Opana ER faced generic competition and patent litigation involving generic-drug manufacturers, including Actavis and other ANDA applicants. The relevant disputes involved the Orange Book patents protecting oxymorphone extended-release products, including formulation and abuse-deterrence claims.

A Paragraph IV certification would assert that a listed patent is invalid, unenforceable or not infringed. The commercial impact depends on:

Whether the generic applicant challenges the specific listed patent
Whether the NDA holder files suit within 45 days
Whether a 30-month stay applies
Whether the patent expires before regulatory approval
Whether a settlement permits an authorized or independent generic launch

The existence of a Paragraph IV challenge does not establish that a patent is invalid. Litigation outcomes, settlements and claim construction rulings must be reviewed by patent number and case docket.

How strong is the patent estate for oxymorphone abuse-deterrent products?

The estate was commercially meaningful because it combined composition, performance, formulation and process limitations.

Estate layer	Strategic value	Main vulnerability
High-molecular-weight polyethylene oxide	Captures a core abuse-deterrent matrix	Alternative polymers or lower molecular weight
500 N breaking strength	Provides an objective mechanical threshold	Testing variation and sub-threshold designs
Extrusion thermoforming	Protects a manufacturing route and resulting structure	Non-extrusion manufacturing
Controlled-release matrix	Targets extended-release opioid products	Different release technology
Gel-forming agents	Addresses aqueous extraction and injection	Alternative excipients or non-gelling systems
Antagonists and irritants	Adds pharmacologic or sensory deterrence	Safety, tolerability and formulation constraints
Core/tubular morphology	Protects internal architecture	Microscopic and claim-construction disputes
Antioxidants and waxes	Adds formulation fallbacks	Easy substitution in many cases

The strongest claim combination is a product that contains oxymorphone, high-molecular-weight polyethylene oxide, controlled-release matrix material, extrusion-derived structure and a breaking strength above 500 N. The broadest claim is more vulnerable to a carefully engineered alternative that changes the polymer, manufacturing route or mechanical profile.

How does U.S. Patent 8,192,722 compare with competing abuse-deterrent opioid patents?

The patent differs from opioid patent estates focused on other active ingredients.

Product or technology	Active ingredient	Typical protection focus
Opana ER reformulation	Oxymorphone	High-strength polyethylene oxide matrix and abuse deterrence
OxyContin reformulation	Oxycodone	Hard dosage form, controlled release and abuse-deterrent technology
Hysingla ER	Hydrocodone	Abuse-deterrent extended-release tablet and formulation architecture
Xtampza ER	Oxycodone	Microsphere or abuse-deterrent multiparticulate formulation
Arymo ER	Morphine	Abuse-deterrent extended-release matrix
Generic opioid products	Varies	Often rely on non-infringement, expired patents or different formulation systems

A competitor using oxycodone rather than oxymorphone would generally fall outside claim 1, but it could face separate patents covering polyethylene oxide matrices, high hardness, extrusion, gel formation or controlled release.

What generic launch risks exist?

The principal generic launch scenarios are:

Scenario 1: Same polymer and extrusion route

This is the highest infringement-risk scenario. An ANDA product using oxymorphone, high-molecular-weight polyethylene oxide and an extrusion-formed tablet with a breaking strength of at least 500 N could read directly on the patent.

Scenario 2: Same active ingredient, different polymer

This reduces risk under the asserted claims if the formulation does not contain the required polyethylene oxide. The applicant must still assess related Grünenthal, Endo and other opioid formulation patents.

Scenario 3: Same polymer, non-extruded product

This may avoid the extrusion limitation, although the outcome depends on whether “thermoformed by extrusion” is treated as a limiting product-by-process requirement.

Scenario 4: Extruded product below 500 N

This may avoid claim 1, but reducing mechanical strength can undermine the product’s abuse-deterrent profile and FDA labeling strategy.

Scenario 5: Immediate-release oxymorphone

An immediate-release product may avoid claims 9 through 11, but claim 1 does not expressly require controlled release. It could still face claim 1 if all other limitations are met.

What geographic coverage does the patent provide?

U.S. Patent 8,192,722 provides rights only in the United States. Parallel protection may exist in Europe and other jurisdictions through the related international patent family, but claim scope, prosecution amendments, validity and expiration dates differ by country.

A global launch requires separate review of:

European Patent Office family members
National validations
Canada and Australia
Japan and South Korea
Manufacturing jurisdictions
Importation and supply-chain exposure
Supplementary protection certificates or local term extensions

Manufacturing outside the United States can still create U.S. exposure if the product is imported, sold, offered for sale or used in the United States.

What licensing deals affected this technology?

Grünenthal licensed abuse-deterrent technology to pharmaceutical companies, including Endo in connection with reformulated Opana ER. The commercial arrangement allowed Endo to use Grünenthal’s technology in an oxymorphone extended-release product. [5]

License scope, royalties, sublicensing rights, patent-control provisions and settlement terms are contractual and may not be fully disclosed in public patent records. A license does not change the patent’s claim scope. It changes which party has authorization to practice the claims and may affect standing, enforcement rights and generic settlement strategy.

Key Takeaways

U.S. Patent 8,192,722 targets oxymorphone abuse-deterrent dosage forms made by extrusion.
Claim 1 requires oxymorphone or a qualifying derivative, polyethylene oxide of at least 0.5 million g/mol, thermoforming by extrusion, no discoloration and a breaking strength of at least 500 N.
Claims 9 through 11 strengthen protection for controlled-release matrix products.
Claims 7 and 8 cover gel-forming agents, irritants, antagonists, emetics, dyes and bitter substances.
Claims 17 through 26 protect extrusion, inert-atmosphere processing, twin-screw extrusion, calendering, pelletization and press-forming methods.
The patent was commercially relevant to reformulated Opana ER and the broader oxymorphone abuse-deterrent product strategy.
The nominal patent term falls in the 2024-2025 period, subject to the USPTO’s official term calculation.
The principal generic design-arounds are a different polymer, a non-extrusion process or a product with breaking strength below 500 N.
Patent expiration does not automatically eliminate all regulatory, formulation, manufacturing or related-family barriers.
Biosimilar risk is not relevant because oxymorphone is a small-molecule active ingredient. The competitive threat is from ANDA-based generic products.

FAQs About U.S. Patent 8,192,722

Does U.S. Patent 8,192,722 cover all Opana ER products?

No. It covers products that satisfy the specific claim limitations. Product identity, formulation version, manufacturing route and Orange Book listing must be matched to the asserted claim.

Can a generic oxymorphone tablet avoid the patent by using direct compression?

Potentially. Direct compression may avoid the extrusion limitation, but the final product must also be assessed against related patents and any applicable product-by-process interpretation.

Does the patent require polyethylene oxide above 1 million g/mol?

Claim 1 requires at least 0.5 million g/mol. Claims 3 and 4 impose the higher threshold of at least 1 million g/mol, with claim 4 specifying approximately 1-15 million g/mol.

Is a 500 N breaking strength required for every claim?

The 500 N limitation appears in claim 1 and is inherited by its dosage-form dependent claims. Process claim 17 refers back to claim 1 and therefore also incorporates the claimed dosage-form requirements.

Are oxymorphone salts covered?

Yes. Claim 27 expressly identifies salts, solvates, esters, ethers and amides as physiologically acceptable compounds and derivatives within the claimed subject matter.

Does FDA withdrawal of Opana ER invalidate the patent?

No. FDA product withdrawal and patent validity are separate legal and regulatory issues. Withdrawal affects commercial marketing and regulatory status, not the legal validity of issued patent claims.

Sources:

United States Patent and Trademark Office. (2012). U.S. Patent No. 8,192,722, abuse-proofed dosage forms.
United States Patent and Trademark Office. (n.d.). Patent Center and patent term adjustment records for U.S. Patent No. 8,192,722.
U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations: Orange Book.
U.S. Food and Drug Administration. (2017). FDA requests removal of Opana ER for risks related to abuse.
Endo International plc. (2011). Annual report and disclosures concerning reformulated Opana ER and abuse-deterrent technology licensing.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Argentina	045352	⤷ Start Trial
Argentina	045353	⤷ Start Trial
Argentina	046994	⤷ Start Trial
Argentina	049083	⤷ Start Trial
Argentina	049839	⤷ Start Trial
Argentina	054328	⤷ Start Trial
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Details for Patent: 8,192,722

Summary for Patent: 8,192,722