US Patent 9,095,615: Claim Scope, Hysingla ER Coverage, and Opioid Patent Landscape
US Patent 9,095,615 is a Purdue Pharma patent directed to abuse-deterrent, extended-release opioid tablets made from a high-polymer polyethylene oxide matrix and cured by heat. Its strongest commercial relevance is hydrocodone bitartrate extended-release tablets, including the formulation used for Hysingla ER. The patent claims a narrow combination of composition, polymer ratios, tablet manufacture, and curing conditions rather than opioids generally.
The patent’s nominal term runs to approximately June 26, 2029, subject to the official USPTO term calculation, terminal disclaimers, patent-term adjustment, and maintenance-fee status. The key infringement risk is concentrated in hydrocodone extended-release tablets that use the claimed polyethylene oxide blend and heat-curing process.
What does US Patent 9,095,615 protect?
The patent protects a cured, shaped, once-daily tablet containing:
| Required element |
Claim 1 requirement |
| Active ingredient |
Opioid or pharmaceutically acceptable salt |
| Low-molecular-weight polyethylene oxide |
Rheological molecular weight below approximately 1,000,000 |
| High-molecular-weight polyethylene oxide |
Rheological molecular weight approximately 7,000,000 |
| Total polyethylene oxide |
At least 79% by weight |
| Low-molecular-weight polyethylene oxide |
At least 22% by weight |
| High-molecular-weight polyethylene oxide |
At least 50% by weight |
| Dosage form |
Cured shaped tablet |
| Release profile |
Once-a-day dosage form |
| Manufacturing process |
Blending, shaping, and thermal curing |
| Curing temperature |
Approximately 60 to 90°C |
| Curing time |
Approximately 15 minutes to 10 hours |
| Additives |
At least one additive |
The claims operate cumulatively. A competing product must satisfy every limitation of an asserted claim to infringe literally. A product using an opioid but lacking the specified polyethylene oxide molecular-weight combination, polymer percentages, or curing process would fall outside the literal scope of claim 1.
What is the commercial purpose of the claimed formulation?
The formulation creates a mechanically robust, high-polymer matrix intended to resist rapid drug extraction, crushing, grinding, or dose dumping. The high-molecular-weight polyethylene oxide supplies substantial matrix strength and swelling characteristics. The lower-molecular-weight polyethylene oxide modifies processability and drug-release behavior.
The claimed curing step changes the physical properties of the compressed tablet. The patent specifically links curing to a reduction in tablet density in dependent claims 28 through 30. The process is therefore material to the claimed product structure, not merely a manufacturing preference.
The formulation is consistent with abuse-deterrent extended-release hydrocodone technology used in Hysingla ER, which FDA approved as an extended-release hydrocodone product with abuse-deterrent properties. [1]
How do the independent and dependent claims differ?
Claim 1 is the only independent claim in the supplied claim set. Claims 2 through 30 narrow the formulation or process.
Claim limitations with the greatest commercial significance
| Claims |
Added limitation |
Commercial effect |
| 2, 12 |
Opioid or hydrocodone at least 2.4% by weight |
Captures higher-drug-load formulations |
| 3 |
Cure time of 15 to 60 minutes |
Narrows manufacturing window |
| 4 |
Cure temperature of 70 to 78°C |
Targets a narrower process range |
| 5 |
Hydrocodone and selected additives |
Directly targets hydrocodone formulations |
| 6, 13, 14, 27 |
Combined time and temperature limits |
Strong process-specific coverage |
| 7, 8 |
Convection curing and mean exhaust temperature |
Captures a defined commercial-scale curing method |
| 9 to 11 |
At least 80%, 85%, or 90% total polyethylene oxide |
Covers highly polymer-loaded tablets |
| 18 |
54% high-molecular-weight polyethylene oxide |
Targets a specific formulation point |
| 19, 20 |
Hydrocodone at least 5% or 10% |
Covers higher-strength tablets |
| 21 to 24 |
Separate low- and high-molecular-weight polymer blends |
Covers staged or segregated blending |
| 23, 24 |
Direct compression of at least one blend |
Narrows processing architecture |
| 25, 26 |
Coating before or after curing |
Extends coverage to coated tablets |
| 28 to 30 |
At least 1% density reduction after curing |
Adds a measurable physical-product limitation |
Claims 5, 12, 13, 18, and 27 are particularly important for hydrocodone products. Claims 9 through 11 create fallback positions at increasingly high total polymer content. Claims 28 through 30 may be more difficult to enforce because they require comparative density testing before and after curing.
What formulation is most directly covered?
The most exposed formulation is a once-daily hydrocodone tablet containing:
- Hydrocodone or hydrocodone bitartrate;
- At least 2.4% hydrocodone active ingredient by composition weight;
- At least 22% low-molecular-weight polyethylene oxide;
- At least 50% high-molecular-weight polyethylene oxide;
- At least 79% combined polyethylene oxide;
- Microcrystalline cellulose, hydroxypropyl cellulose, magnesium stearate, or a combination;
- Compression into a shaped tablet;
- Convection curing at 70 to 78°C for 15 to 60 minutes;
- Optional coating before or after curing.
Claim 18 identifies a formulation containing 54% high-molecular-weight polyethylene oxide. A product using 54% high-molecular-weight polyethylene oxide, at least 22% low-molecular-weight polyethylene oxide, and hydrocodone at or above the claimed threshold would present a particularly direct claim-mapping risk.
What is the scope of the polyethylene oxide limitations?
The claims use rheological molecular-weight descriptions rather than only commercial grade names. That distinction matters. A polyethylene oxide sold under a particular brand or grade is not automatically within or outside the claims. The relevant question is whether its rheologically measured molecular weight falls within the claimed categories.
The composition thresholds also create a mathematical constraint:
- Low-molecular-weight polyethylene oxide: at least 22%;
- High-molecular-weight polyethylene oxide: at least 50%;
- Combined polyethylene oxide: at least 79%.
The separate polymer minimums total 72%, so claim 1 requires at least another 7% of polyethylene oxide beyond the minimum amounts, or a higher amount of one or both polymer fractions. A formulation containing 22% low-molecular-weight polymer and 50% high-molecular-weight polymer would not satisfy the 79% combined limitation unless the composition contains at least 7% additional qualifying polyethylene oxide.
The weight basis is the total composition, not necessarily the total finished tablet including a coating. Claim construction may require determining whether coating weight is excluded from the claimed composition weight, depending on the patent specification and prosecution history.
When does US Patent 9,095,615 expire?
The patent traces to a priority date of approximately June 26, 2008. The expected base patent term is approximately 20 years from the earliest effective nonprovisional filing date, producing a nominal expiration around June 26, 2029. The exact expiration date must be determined from the USPTO term calculation and any terminal disclaimer or patent-term adjustment. [2]
| Event |
Date or period |
| Earliest claimed priority |
June 26, 2008 |
| Patent grant |
July 28, 2015 |
| Nominal expiration |
Approximately June 26, 2029 |
| Relevant protection |
Composition, dosage form, and manufacturing process |
| Small-molecule exclusivity |
Separate from patent term |
The patent term is distinct from FDA regulatory exclusivity. FDA exclusivity can delay certain ANDA approvals but does not extend the patent expiration date. [3]
What is the FDA and Orange Book status relevant to this patent?
Hysingla ER is an FDA-approved extended-release hydrocodone bitartrate product. FDA classified the product as an abuse-deterrent opioid formulation. The product is administered once daily and is available in multiple strengths. [1]
A patent’s presence in the Orange Book depends on whether the NDA holder submitted it for listing and whether it claims the approved drug, a method of using the drug, or a drug-product formulation. Orange Book listing does not establish validity or infringement. It creates an FDA notice function for ANDA applicants and can trigger the Hatch-Waxman patent-certification process. [3]
For a generic applicant, the relevant certifications could include:
- Paragraph I: no patent information has been submitted;
- Paragraph II: the patent has expired;
- Paragraph III: approval is sought after patent expiration;
- Paragraph IV: the patent is invalid, unenforceable, or will not be infringed.
A Paragraph IV certification can trigger patent litigation if the NDA holder sues within the statutory period. A timely suit can impose a 30-month stay on ANDA approval, subject to statutory exceptions and court action. [4]
Which generic launch scenarios create the greatest risk?
Formulation-matching generic
A generic hydrocodone extended-release tablet that reproduces the Hysingla-type polymer matrix faces the highest risk. The most important claim elements would be:
- Hydrocodone active ingredient;
- High- and low-molecular-weight polyethylene oxide;
- At least 79% combined polymer;
- At least 22% low-molecular-weight polymer;
- At least 50% high-molecular-weight polymer;
- Heat curing in the claimed temperature and time ranges.
A generic company could attempt to design around the patent by changing the polymer ratio, using a different molecular-weight distribution, eliminating the curing step, or adopting a different abuse-deterrent technology.
Process design-around
A product with a similar final dissolution profile may avoid literal infringement if it is manufactured without the claimed curing process or outside the specified process conditions. That strategy carries risk because claim 1 is a product-by-process claim. The legal question would be whether the claimed manufacturing limitations restrict the scope to products made by the recited process or whether the resulting product characteristics are inherent in a product made by an alternative process.
Non-PEO abuse-deterrent formulation
A formulation using a different abuse-deterrent platform, such as a sequestered antagonist, wax-based matrix, multiparticulate system, or different polymer system, would generally present a lower literal-infringement risk. It could still face other Purdue or third-party patents.
How strong is the patent estate?
The patent has meaningful strength in three areas:
Narrow technical combination
The combination of polymer molecular weights, polymer percentages, opioid loading, tablet geometry, and curing conditions is technically specific. That specificity can support validity by distinguishing broad prior art directed generally to sustained-release opioid matrices.
Multiple fallback claims
The dependent claims preserve coverage for:
- Higher polymer loading;
- 54% high-molecular-weight polymer;
- Hydrocodone;
- Higher hydrocodone loading;
- Convection curing;
- Direct compression;
- Coating;
- Density reduction.
If a broad claim faces prior-art pressure, the narrower hydrocodone and process claims may remain commercially important.
Potential weaknesses
The patent also has vulnerabilities:
- The molecular-weight terms rely on rheological measurements and may require expert testing;
- Product-by-process limitations can create claim-construction disputes;
- The claims contain overlapping percentage limitations that may invite enablement or written-description challenges at the boundaries;
- Density-reduction claims require reliable pre- and post-curing measurements;
- Prior art involving polyethylene oxide opioid matrices, thermal curing, or abuse-deterrent tablets could affect validity.
Patent strength therefore depends on the specific accused formulation, prosecution history, prior-art record, and test data. The claim text alone does not establish validity.
How does this patent compare with competing opioid patent estates?
| Product or platform |
Company |
Primary technology |
Relationship to US 9,095,615 |
| Hysingla ER |
Purdue Pharma |
Hydrocodone in high-polymer cured matrix |
Closest commercial relationship |
| OxyContin ER |
Purdue Pharma |
Controlled-release oxycodone matrix |
Separate oxycodone patent estate |
| Xtampza ER |
Collegium Pharmaceutical |
DETERx microsphere formulation |
Different abuse-deterrent platform |
| Arymo ER |
Egalet |
Abuse-deterrent morphine matrix |
Different formulation and opioid |
| Zohydro ER |
Zogenix, later transferred commercial interests |
Extended-release hydrocodone |
Different product and patent estate |
| Generic ER opioids |
Multiple manufacturers |
Varying matrices and delivery systems |
Risk depends on polymer and process overlap |
There is no biosimilar pathway for hydrocodone tablets. Hydrocodone is a small molecule, so competitive entry proceeds through the ANDA pathway rather than through a biosimilar application. [3]
What patent litigation and settlement issues matter?
The relevant litigation question is whether an ANDA applicant certified Paragraph IV against the patent and whether Purdue filed suit within the statutory period. A settlement could establish a negotiated generic entry date, license terms, manufacturing restrictions, or an authorized-generic arrangement. Such terms are not established by the claims themselves.
For diligence, the most important documents are:
- Orange Book patent listings for the relevant NDA;
- FDA Paragraph IV litigation records;
- Federal district court dockets;
- Abbreviated New Drug Application approval records;
- Patent assignment and maintenance-fee records;
- Any terminal disclaimer or reexamination certificate.
Patent litigation involving opioid formulations often turns on claim construction, anticipation, obviousness, inherent properties, and the meaning of manufacturing limitations. A generic applicant’s strongest design-around position would usually involve avoiding the claimed PEO ratios or the claimed thermal-curing process rather than merely changing tablet shape or coating.
What manufacturing and geographic barriers remain?
US Patent 9,095,615 is a US right. It does not automatically block manufacture, sale, or importation outside the United States. Parallel protection must be assessed by country and patent family.
Manufacturing risk is highest where the process uses:
- Separate low- and high-molecular-weight PEO blends;
- Direct compression;
- Convection curing;
- Mean exhaust temperature control at 70 to 78°C;
- A high polymer load of 79% or more.
A manufacturer could avoid a US process claim by producing abroad, but importation or US commercial activity may still create infringement exposure under 35 U.S.C. § 271. Process evidence may also be discoverable through batch records, equipment settings, master manufacturing records, and regulatory submissions.
Key Takeaways
- US Patent 9,095,615 is directed to cured, once-daily opioid tablets using a high- and low-molecular-weight polyethylene oxide matrix.
- The core threshold is at least 79% combined polyethylene oxide, with at least 22% low-molecular-weight and 50% high-molecular-weight polymer.
- Claims 5, 12, 13, 18, and 27 are the most commercially relevant hydrocodone claims.
- The patent closely tracks the technical architecture of Hysingla ER.
- The nominal expiration date is approximately June 26, 2029, subject to the official USPTO term calculation.
- The patent is a small-molecule formulation patent, so biosimilar risk does not apply.
- Generic risk is highest for products reproducing the PEO ratios, hydrocodone loading, and 70 to 78°C convection-curing process.
- A non-PEO abuse-deterrent platform or materially different manufacturing process offers the clearest design-around path.
- Orange Book listing, Paragraph IV certifications, ANDA litigation, and settlement terms must be evaluated separately from the patent claims.
FAQs
Does US Patent 9,095,615 cover all extended-release hydrocodone products?
No. It covers products meeting the claimed polyethylene oxide composition, opioid, tablet, and curing limitations. Hydrocodone products using different matrices or manufacturing processes may fall outside the claims.
Does a tablet with 78% polyethylene oxide infringe claim 1?
Not literally under the combined-polyethylene-oxide limitation, because claim 1 requires at least 79% by weight. Other claims or related patents could still be relevant.
Is 54% high-molecular-weight polyethylene oxide specifically claimed?
Yes. Claim 18 depends on the hydrocodone formulation and specifies 54% high-molecular-weight polyethylene oxide. The exact claim combination must be met.
Can a generic avoid the patent by changing only the tablet coating?
Usually not if the uncoated tablet still satisfies an asserted claim. Claims 25 and 26 expressly address coating before or after curing, although the full claim limitations must still be met.
Does the patent protect the abuse-deterrent use of hydrocodone itself?
No. The patent protects a particular opioid tablet composition and manufacturing architecture. It does not grant a general monopoly over hydrocodone abuse deterrence.
References
- U.S. Food and Drug Administration. (2014). Hysingla ER prescribing information.
- U.S. Patent and Trademark Office. (2015). U.S. Patent No. 9,095,615, Cured shaped articles having controlled release properties.
- U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations, commonly known as the Orange Book.
- U.S. Code. 21 U.S.C. § 355(j), abbreviated applications and patent certifications.
