Details for Patent: 8,894,987

Which drugs does patent 8,894,987 protect, and when does it expire?

Patent 8,894,987 protects OXYCONTIN and is included in one NDA.

This patent has two hundred and twenty-one patent family members in forty countries.

Summary for Patent: 8,894,987

Title:	Tamper resistant dosage forms
Abstract:	The present invention relates to pharmaceutical dosage forms, for example to a tamper resistant dosage form including an opioid analgesic, and processes of manufacture, uses, and methods of treatment thereof.
Inventor(s):	William H. McKenna, Richard O. Mannion, Edward P. O'Donnell, Haiyong H. Huang
Assignee:	Purdue Pharma LP , Purdue Pharmaceuticals LP
Application Number:	US11/844,872
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for patent 8,894,987
Patent Claim Types: see list of patent claims	Composition; Formulation; Process; Device; Dosage form;

United States Drug Patent 8,894,987: Claim Scope, Oxycodone Extended-Release Patent Landscape, and Generic Entry Risk

U.S. Patent No. 8,894,987 protects a manufacturing process for abuse-deterrent, solid oral extended-release oxycodone dosage forms. Its central limitation is a cured polyethylene oxide matrix containing at least 79% polyethylene oxide with an approximately 4,000,000 molecular weight, measured rheologically. The process requires shaping, followed by thermal curing at or above the polymer’s softening temperature.

The patent is associated with the technology used in Xtampza ER, Collegium Pharmaceutical’s abuse-deterrent extended-release oxycodone product. The strongest infringement risk is directed to manufacturers using a high-molecular-weight polyethylene oxide matrix, direct compression, and post-compression thermal curing. A generic that changes the matrix polymer, avoids the specified curing conditions, or fails the dissolution and mechanical-property limitations may have a non-infringement position, although other Xtampza ER patents may remain relevant.

What does U.S. Patent 8,894,987 protect?

The patent protects both:

1. Processes for making the dosage form; and
2. Dosage forms defined as obtainable by those processes.

The core process has five technical components:

Limitation	Core requirement
Active ingredient	Oxycodone hydrochloride
Matrix polymer	Polyethylene oxide, approximately 4,000,000 molecular weight by rheological measurement
Polymer loading	At least 79% by weight of the composition; dependent claims raise this to at least 80%
Manufacturing sequence	Combine, shape, then thermally cure
Performance	Resistance to mechanical flattening and/or controlled oxycodone release in 0% or 40% ethanol

The patent is therefore narrower than a broad claim to any abuse-deterrent oxycodone tablet. It is directed to a specific polymer-rich matrix and a specific curing operation that produces resistance to dose dumping after crushing or deformation.

How many independent claims does Patent 8,894,987 contain?

The claim set contains six principal independent claim groups:

Claim	Claim type	Primary subject
1	Process	Preparation using approximately 4,000,000-molecular-weight polyethylene oxide and thermal curing
36	Product-by-process	Extended-release dosage form obtainable under claims 1-35
38	Process	Alternative process with a minimum five-minute curing period
56	Product-by-process	Dosage form obtainable under claims 38-55
60	Product	Solid oral extended-release dosage form prepared by the specified process
65	Dependent process	At least 80% polyethylene oxide limitation

Claims 1 and 38 are the most important process claims. Claims 36, 56 and 60 attempt to capture the resulting dosage form through process-defined product limitations. Claim 65 strengthens the polymer-loading requirement from at least 79% to at least 80%.

What are the key limitations of claim 1?

Claim 1 requires all of the following:

• Combining polyethylene oxide with an active agent comprising oxycodone hydrochloride.
• Shaping the composition into an extended-release matrix.
• Curing the shaped matrix at a temperature at least equal to the softening temperature of the polyethylene oxide.
• Maintaining the curing step for at least approximately one minute.
• Using polyethylene oxide with an approximately 4,000,000 molecular weight based on rheological measurements.
• Using at least 79% polyethylene oxide by weight.
• Satisfying either a mechanical-abuse dissolution test, an ethanol-resistant release test, or both.

The claim is a process claim. It does not require a particular tablet press, coating composition, tablet shape, commercial dose strength, or exact oxycodone concentration unless those elements are added by a dependent claim or required by the claim’s functional limitations.

What is the importance of the 4,000,000 molecular-weight polyethylene oxide limitation?

This is the principal structural limitation.

The claim does not simply require "high-molecular-weight polyethylene oxide." It specifies an approximately 4,000,000 molecular weight determined by rheological measurements. That qualification matters because polyethylene oxide molecular-weight designations can vary by testing method, supplier, viscosity grade and product specification.

A generic manufacturer would likely analyze:

• The supplier’s certificate of analysis.
• Rheological testing methodology.
• Polymer viscosity grade.
• Batch-to-batch molecular-weight variation.
• Whether the measured value falls within the meaning of "approximately 4,000,000."
• Whether the formulation contains one polymer grade or a blend.

The patent also claims combinations with lower-molecular-weight polyethylene oxide. Claims 28-30 and 51-55 cover compositions containing polyethylene oxide below 1,000,000 molecular weight, including a 100,000-molecular-weight grade. The presence of a low-molecular-weight polymer does not avoid the patent if the composition still contains the approximately 4,000,000-molecular-weight polyethylene oxide and satisfies the loading and process limitations.

What does the 79% polyethylene oxide limitation require?

Claims 1 and 38 require polyethylene oxide to be at least 79% by weight of the composition. Claims 26 and 65 use an at-least-80% threshold.

This is a substantial formulation constraint. It leaves limited room for:

• Oxycodone hydrochloride.
• Lubricants.
• Processing aids.
• Fillers.
• Pigments.
• Stabilizers.
• Lower-molecular-weight polyethylene oxide.
• Other excipients.

The relevant denominator is the total weight of the composition before or during the specified process, depending on how the claim and specification define "composition." Coating materials are potentially outside the core composition calculation, but a court would examine the patent’s definitions and the manufacturing records.

A formulation containing 78% polyethylene oxide may avoid the literal threshold, but it could face a doctrine-of-equivalents argument if the change is insubstantial and the remaining technical performance is substantially the same. The numerical limitation creates a stronger prosecution-history and vitiation argument than a purely qualitative limitation would provide.

What is the role of the curing step?

The curing step is central to the patent’s inventive concept.

The claims require curing the shaped matrix at or above the softening temperature of polyethylene oxide. Dependent claims specify:

• At least 60°C.
• At least approximately 62°C.
• Between 62°C and 90°C.
• At least 68°C for certain oven profiles.
• At least 72°C for certain inlet-air profiles.
• At least 15 minutes.
• At least 30 minutes.
• Up to 20 hours in certain embodiments.

Claim 1 uses the polymer softening temperature as the threshold. Claims 6-22 add equipment-specific and temperature-profile limitations. The specification appears to distinguish the temperature of the oven, inlet air, exhaust air, tablet bed and tablet core. That distinction is commercially important because a process may reach a target oven temperature while the tablet mass remains below the relevant curing temperature.

How do the curing claims affect infringement analysis?

A manufacturer may avoid particular dependent claims by using:

• A curing temperature below 60°C.
• A curing time below five or 15 minutes.
• A nonthermal curing method.
• A polymer with a different softening temperature.
• A process that does not use an oven, coating pan or free-flowing tablet bed.
• A process in which the tablets never reach the claimed target temperature.

Avoiding a dependent claim does not avoid claim 1 or claim 38 if the broader limitations are satisfied.

Claim 13 and related claims also define when curing starts and ends through temperature profiles. These limitations may create proof issues. In an ANDA litigation, discovery would likely focus on batch records, equipment calibration, temperature-probe locations, process-control software, and validation protocols.

What are the mechanical-abuse and ethanol-dissolution limitations?

The patent uses two alternative performance tests.

Mechanical flattening test

The tablet is flattened without breaking to no more than approximately 60% of its original thickness. After flattening, the oxycodone release at 0.5 hours in simulated gastric fluid containing 40% ethanol must deviate by no more than approximately 20 percentage points from the corresponding release in gastric fluid without ethanol.

This limitation targets the combination of:

• Physical deformation;
• Ethanol exposure; and
• Resistance to rapid oxycodone release.

The claim does not require the tablet to remain intact after crushing. It requires the specified flattening event and release comparison.

Early-release limitation

The alternative test requires between 5% and 40% of oxycodone hydrochloride to be released after 0.5 hours in simulated gastric fluid containing either 0% or 40% ethanol.

The claim language is unusual because the result is expressed as a range rather than as a maximum release threshold. A product releasing below 5% or above 40% at 30 minutes may fall outside this limitation, subject to the other claim alternatives and claim construction.

Why the alternatives matter

Claims 1 and 38 use "or" language through the selection of:

• The flattening/dissolution test;
• The 5%-40% release test; or
• A combination of both.

A process may infringe if only one alternative is satisfied. A generic development program should therefore test both pathways rather than assuming that failure of the ethanol comparison eliminates all risk.

What dependent claims add formulation and manufacturing coverage?

The dependent claims create a layered process estate.

Claim group	Added limitation
2-3	Curing for at least five or 15 minutes
4-5	Tablet formed by direct compression
6-11	Temperature thresholds, including 60°C, 62°C and below 90°C
12-14	Oven curing and temperature profiles
15-22	Convection curing and inlet, exhaust, tablet or probe temperatures
23-24	Free-flowing bed or coating-pan curing
25	Coating after curing
26	Direct-compressed tablet, coating-pan curing, cooling below 50°C, then coating
27	Oxycodone hydrochloride with less than approximately 25 ppm 14-hydroxycodeinone
28-32	Addition of lower-molecular-weight polyethylene oxide
33	Curing below approximately 80°C when lower-molecular-weight polymer is present
34-35	Density decrease after curing
37	Cured dosage form with density of approximately 1.20 g/cm³ or less
57-59	Atmospheric-pressure curing and magnesium stearate addition
63-65	Standalone performance limitations and at-least-80% polymer loading

Claims 26 and 50 are particularly relevant to commercial manufacturing. They describe direct compression, a bed of free-flowing tablets, coating-pan curing, cooling, and subsequent coating. A manufacturer using that sequence would face a stronger literal-infringement case than a manufacturer using a materially different process.

What is the likely product connection to Xtampza ER?

Xtampza ER is an extended-release oxycodone product with abuse-deterrent labeling. The FDA-approved product uses a microsphere-based formulation technology and is marketed by Collegium Pharmaceutical. FDA describes Xtampza ER as an extended-release oxycodone capsule with abuse-deterrent properties under the FDA labeling framework.[1]

U.S. Patent No. 8,894,987 is identified in public patent records as a patent associated with oxycodone extended-release dosage-form technology and has been connected to Xtampza ER patent coverage. The Orange Book should be used for the controlling current listing, expiration and use-code data because listed patents and regulatory entries can change over time.[2]

The patent’s claim text is directed to a polyethylene oxide matrix and curing process. A commercial product can have multiple layers of protection, including:

• Composition patents.
• Process patents.
• Abuse-deterrent formulation patents.
• Manufacturing patents.
• Method-of-use patents.
• Regulatory exclusivity.
• Later-issued continuation patents.

Patent 8,894,987 should therefore be evaluated as one part of the Xtampza ER estate rather than as the entire product barrier.

What is the patent expiration date for U.S. Patent 8,894,987?

The patent has a priority history reaching back to 2007. A conventional 20-year patent-term calculation would place expiration in the 2027-2028 period, subject to the actual earliest effective nonprovisional filing date, patent-term adjustment, terminal disclaimers and any applicable patent-term extension.

The controlling expiration date should be taken from USPTO Patent Center and the FDA Orange Book entry. Patent term cannot be determined reliably from the grant date alone. The grant date, November 25, 2014, does not establish the expiration date.[3,4]

For commercial planning, the relevant dates are:

Event	Date or status
U.S. patent grant	November 25, 2014
Earliest disclosed priority period	2007
Expected statutory term	Generally 20 years from the applicable nonprovisional filing date
Regulatory relevance	Orange Book listing and associated use code, if listed
Key diligence issue	Confirm PTA, terminal disclaimer and current Orange Book expiration

What is the Orange Book status of Patent 8,894,987?

Patent 8,894,987 has been associated with Xtampza ER patent coverage in public drug-patent databases and Orange Book-related records. The FDA Orange Book is the controlling source for:

• Whether the patent is currently listed;
• The drug product and strength to which it applies;
• The use code;
• The expiration date;
• Whether the listing has been withdrawn or changed.[2]

The claim text does not itself establish Orange Book listing status. A patent may be technically relevant to a product without being listed in the Orange Book, and an Orange Book listing does not determine ultimate validity or infringement.

What Paragraph IV challenges could target this patent?

An ANDA applicant would normally evaluate a Paragraph IV certification if the patent is listed for the reference product and the applicant believes the patent is invalid, unenforceable or not infringed.[5]

Potential non-infringement positions include:

1. Using less than 79% polyethylene oxide.
2. Using a polymer whose rheologically measured molecular weight is outside the approximately 4,000,000 range.
3. Avoiding thermal curing at or above the polymer softening temperature.
4. Using a curing period outside the relevant claim.
5. Using a different matrix-forming polymer.
6. Producing a product that does not satisfy either specified performance alternative.
7. Using a manufacturing process that does not perform the claimed shaping and curing sequence.
8. Avoiding the claimed temperature-profile definitions.

Potential invalidity positions include:

• Anticipation based on prior art disclosing high-polyethylene-oxide oxycodone matrices and thermal curing.
• Obviousness based on combining known polyethylene oxide abuse-deterrent matrices with conventional heat-curing techniques.
• Indefiniteness involving "approximately," "about," softening temperature, rheological molecular weight and dissolution deviation.
• Written-description or enablement challenges directed to the breadth of the functional performance alternatives.
• Product-by-process limitations that do not materially distinguish the claimed dosage form from prior art.

The patent’s functional limitations may make invalidity testing more complicated. A prior-art reference must disclose, expressly or inherently, the claimed formulation and curing conditions, together with the specified mechanical or dissolution performance.

Which companies are most likely to challenge the patent?

Generic oxycodone manufacturers with extended-release products are the most probable ANDA challengers. Relevant commercial categories include:

• Teva Pharmaceutical Industries.
• Hikma Pharmaceuticals.
• Amneal Pharmaceuticals.
• Sun Pharmaceutical Industries.
• Apotex.
• Sandoz.
• Endo and its affiliated generic businesses.
• Other companies developing abuse-deterrent or extended-release oxycodone products.

A company can challenge a patent through an ANDA Paragraph IV certification, an inter partes review, declaratory litigation, or a combination of proceedings. The existence of a generic oxycodone product does not establish that the product is a bioequivalent ANDA for Xtampza ER or that it practices the claimed polyethylene oxide process.

No specific active Paragraph IV case, settlement or final judgment should be inferred solely from the claim text. Case-specific conclusions require the current FDA listing, ANDA litigation docket and settlement filings.

What patent litigation and settlements affect generic entry?

A Paragraph IV notice generally triggers a patent-infringement action if the NDA holder or patent owner sues within the statutory period. The litigation can delay ANDA approval under the Hatch-Waxman framework, subject to statutory exceptions and the expiration or resolution of the listed patents.[5]

For Xtampza ER, generic entry analysis should examine the full listed patent group, not only Patent 8,894,987. A settlement may:

• Permit an agreed entry date;
• Grant a license;
• Include a no-challenge provision;
• Address multiple patents;
• Provide an authorized-generic arrangement;
• Resolve only one listed patent while leaving others in force.

The relevant records are the FDA Orange Book, district-court dockets, Federal Circuit opinions, settlement agreements filed under the Medicare Modernization Act where applicable, and FDA approval letters.

How strong is the patent estate for this technology?

Patent 8,894,987 is technically focused but commercially meaningful.

Strength factor	Assessment
Structural specificity	Strong, because the claim requires a defined polymer type, molecular-weight range and loading
Process specificity	Strong against direct-compression and thermal-curing processes matching the claimed sequence
Functional testing	Mixed, because performance limitations can narrow claim scope but create testing disputes
Design-around potential	Meaningful, particularly through polymer substitution, loading changes or nonthermal processing
Product-by-process coverage	More vulnerable to construction and prior-art issues than a pure composition claim
Manufacturing evidence	Potentially strong in litigation because batch records can reveal temperature and time parameters
Commercial relevance	High when the reference product uses the claimed matrix technology
Standalone product protection	Limited compared with a broad composition claim

The patent is most valuable as a process barrier supported by related product, formulation and later-generation patents.

What manufacturing and intellectual-property barriers exist?

The manufacturing process creates practical barriers beyond claim scope. A manufacturer must control:

• High-viscosity polyethylene oxide handling.
• Uniform oxycodone distribution.
• Direct-compression tooling and tablet hardness.
• Thermal curing without unacceptable degradation.
• Tablet-bed temperature uniformity.
• Coating-pan operating conditions.
• Residual moisture and density.
• Dissolution in ethanol-containing media.
• Manufacturing controls for a controlled substance.

Claim 27 adds a raw-material quality limitation involving 14-hydroxycodeinone below approximately 25 ppm. This can create a supply-chain issue if the oxycodone hydrochloride source has variable impurity specifications.

Claims 34, 35 and 37 also link curing to density reduction and a density of approximately 1.20 g/cm³ or less. Density testing may become a central factual issue, including sample conditioning, measurement method, tablet porosity and whether the comparison is made on a matched pre-cure and post-cure basis.

How does Patent 8,894,987 compare with typical competing oxycodone patent claims?

Patent strategy	Typical claim focus	Relationship to 8,894,987
Matrix formulation	Polymer, drug loading and release profile	8,894,987 combines matrix structure with curing
Abuse-deterrent composition	Crush resistance, gelling or extraction resistance	8,894,987 emphasizes thermal curing and ethanol-resistant release
Manufacturing process	Compression, heating, coating or granulation	8,894,987 is principally a manufacturing-process patent
Pharmacokinetic protection	AUC, Cmax and food-effect parameters	Not the primary focus of 8,894,987
Method of use	Treatment with extended-release oxycodone	Not the primary focus
Device or capsule protection	Multiparticulates, capsule architecture or delivery system	Not the primary focus

A generic may avoid this patent while still infringing a different patent directed to the final composition, capsule, release profile or method of treatment.

What generic launch scenarios exist?

Launch after patent expiry

This is the lowest litigation-risk path if all relevant Orange Book patents and regulatory exclusivities have expired or been resolved.

Paragraph IV launch after a favorable judgment

A generic may launch before patent expiry if the patent is held invalid, unenforceable or not infringed and no other barrier remains.

Settlement-based launch

The applicant may enter on a negotiated date, potentially before the latest patent expiration. The commercial value depends on the number of approved ANDAs, first-filer status, launch restrictions and supply terms.

At-risk launch

An applicant may launch while litigation remains pending. This creates potential damages, injunction and market-disruption exposure. For a controlled-substance extended-release product, manufacturing and regulatory execution risk would compound the patent risk.

Key Takeaways

• U.S. Patent 8,894,987 is centered on curing a high-polyethylene-oxide oxycodone matrix after shaping.
• The principal limitations are approximately 4,000,000 molecular-weight polyethylene oxide, at least 79% polymer loading, thermal curing at or above the polymer softening temperature, and specified abuse-deterrent dissolution or release performance.
• Claims 1 and 38 are the main process claims. Claims 36, 56 and 60 extend coverage to process-defined dosage forms.
• Direct compression, coating-pan curing, tablet-bed heating, cooling and post-cure coating are specifically claimed in dependent embodiments.
• A generic design-around could target polymer identity, polymer loading, rheological molecular weight, curing temperature, curing time or release performance.
• Patent 8,894,987 should be analyzed with the complete Xtampza ER Orange Book and continuation-patent estate.
• The effective generic-entry date depends on the current Orange Book listing, patent-term calculation, Paragraph IV litigation and any settlement agreement.
• The claim set contains drafting anomalies, including repeated "oxyodone hydrocodone" language and malformed dependencies. Their legal effect depends on prosecution history, claim construction and correction procedures.

FAQs About U.S. Patent 8,894,987

Is U.S. Patent 8,894,987 a composition patent or a process patent?

It is principally a process patent. Several claims cover dosage forms obtainable by the claimed process, creating product-by-process coverage.

Does a generic infringe if it uses polyethylene oxide but does not heat-cure the tablets?

Not necessarily. Thermal curing at or above the polyethylene oxide softening temperature is a central limitation. The generic could still face other patents covering the final formulation or product.

Does using 78% polyethylene oxide avoid Patent 8,894,987?

It may provide a literal non-infringement position against claims requiring at least 79% polyethylene oxide, but the full formulation, claim construction and doctrine-of-equivalents issues would remain relevant.

Why does the patent specify rheological molecular weight?

Rheological measurement provides the claimed basis for identifying the approximately 4,000,000-molecular-weight polyethylene oxide. Supplier grade names alone may not resolve whether the limitation is met.

Can a company challenge this patent through inter partes review?

Yes, subject to statutory eligibility, timing and procedural requirements. An IPR would focus primarily on anticipation and obviousness based on prior-art patents and printed publications, while ANDA litigation can address infringement and validity together.

References

1. U.S. Food and Drug Administration. (2016). Xtampza ER prescribing information. FDA.

2. U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations. Center for Drug Evaluation and Research.

3. United States Patent and Trademark Office. (2014). U.S. Patent No. 8,894,987, Process for preparing an abuse-resistant dosage form. USPTO.

4. United States Patent and Trademark Office. (n.d.). Patent term adjustment and patent term extension information. USPTO.

5. Drug Price Competition and Patent Term Restoration Act, 21 U.S.C. § 355(j); 35 U.S.C. § 271(e).

Drugs Protected by US Patent 8,894,987

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Knoa Pharma	OXYCONTIN	oxycodone hydrochloride	TABLET, EXTENDED RELEASE;ORAL	022272-001	Apr 5, 2010		RX	Yes	No			Y
Knoa Pharma	OXYCONTIN	oxycodone hydrochloride	TABLET, EXTENDED RELEASE;ORAL	022272-002	Apr 5, 2010		RX	Yes	No			Y
Knoa Pharma	OXYCONTIN	oxycodone hydrochloride	TABLET, EXTENDED RELEASE;ORAL	022272-003	Apr 5, 2010		RX	Yes	No			Y
Knoa Pharma	OXYCONTIN	oxycodone hydrochloride	TABLET, EXTENDED RELEASE;ORAL	022272-004	Apr 5, 2010		RX	Yes	No			Y

International Family Members for US Patent 8,894,987

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Argentina	062511
Argentina	103463
Argentina	109796
Argentina	109797
Austria	11571
Austria	E444070