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Patent landscape, scope, and claims: |
Scope and Claims for US Patent 9,492,391 (Pain Treatment With Air-Cured Polyethylene Oxide Opioid Tablets) and the US Patent Landscape
US Drug Patent 9,492,391 is directed to methods of treating pain using once-daily or twice-daily extended-release opioid (or opioid salt) tablets whose release is controlled by air-cured, compression-shaped matrices containing high molecular weight (HMW) polyethylene oxide (PEO) and, optionally, low molecular weight (LMW) PEO, with curing defined by heated-air parameters and additional tablet mechanical and stability characteristics.
What exactly does US Patent 9,492,391 claim, and what is the invention core?
Core claimed concept (claim 1):
A pain-treatment method where the patient receives an extended-release pharmaceutical tablet containing:
-
First air-cured matrix:
- Compression-shaped matrix then air-cured “without compression”
- Cured by heated air at ≥ about 62°C for ≥ about 5 minutes
- Matrix comprises:
- opioid or pharmaceutically acceptable salt, and
- HMW PEO with rheology-defined “approximate molecular weight” selected from:
- ~4,000,000
- ~7,000,000
- or combination thereof
- optional LMW PEO with “approximate molecular weight < 1,000,000”
-
Optional second air-cured matrix:
- Includes opioid plus LMW PEO (< 1,000,000)
-
Optional coating
- Tablet provides once-daily or twice-daily extended release
-
Composition thresholds in the uncoated tablet:
- HMW PEO is at least 54 wt% of the uncoated tablet
- If LMW PEO is present: LMW PEO is at least 10 wt% of the uncoated tablet
Key technical “hooks” within the claim:
- Process hook: compression shaping followed by air curing without compression at specific heated-air ranges.
- Polymer molecular-weight selection hook: HMW PEO is restricted to ~4M or ~7M (rheology-defined).
- Composition dominance hook: HMW PEO constitutes a majority threshold (≥54 wt%).
- Architecture hook: single matrix or dual-matrix design (optional second matrix using LMW PEO).
- Product performance hook: once- or twice-daily extended release (functional limitation).
Which claim elements are most limiting versus broadly written in US 9,492,391?
Most limiting elements (likely to drive infringement boundaries)
- HMW PEO molecular weight range is narrow and discrete: ~4,000,000 or ~7,000,000 (or combination), based on rheological measurements.
- Curing conditions are bounded:
- At least 62°C for at least 5 minutes in claim 1
- Further narrowed in dependent claims to 62–90°C and 15 minutes–10 hours with cooling parameters.
- Composition thresholds are very high:
- HMW PEO ≥54 wt% of uncoated tablet
- If dual matrix exists, LMW PEO has floor thresholds that can reach ≥20 wt% (claims 7–9)
- Dual-matrix option can be used to widen/strengthen coverage: presence of a second matrix plus LMW PEO has its own weight floors (claims 7–13).
Less limiting elements (tend to be easier to match or read on many products)
- Opioid list in dependent claim 2: oxycodone, hydrocodone, morphine, hydromorphone, oxymorphone (plus salts).
- Salt list in claim 5: broad set of common opioid salts (HCl, hydrobromide, sulfate, phosphate, formate, acetate, trifluoroacetate, maleate, tartrate).
- Optional coating: coating presence is not required in claim 1 and is carried as optional.
How do claims 2–6 define opioid scope, salt forms, matrix design, and coating impact?
Claim 2 (opioid species scope)
- Opioid/salt is present at ≥2.4 wt% of uncoated tablet.
- Opioids limited to: oxycodone, hydrocodone, morphine, hydromorphone, oxymorphone.
Claim 3–4 (curing windows and cooling)
- Claim 3:
- Curing via heated air about 62–90°C for about 15 min–10 hours
- then cooling
- Claim 4:
- tighter range:
- air temperature 65–90°C
- duration 15 min–8 hours
- cooling includes exposure to air < ~62°C
Claim 5 (salt identity)
- Salt selection is constrained to a defined set of conventional salts.
Claim 6 (coating as an architecture feature)
- One or both matrices can further comprise a coating.
Practical impact:
These dependent claims establish a ladder of specificity. A product that matches curing conditions (esp. claim 4 ranges) and uses one of the listed opioid families can be pulled into infringement by showing the PEO molecular weight identity and wt% thresholds.
What do claims 7–14 require for dual-matrix tablets and PEO weight fractions?
Claim 7–9 (dual matrix presence and LMW PEO floors)
- Claim 7: if second matrix is present, LMW PEO must be ≥20 wt% of total uncoated tablet.
- Claim 8 repeats claim 7 logic (dependent duplication).
- Claim 9 tightens further:
- LMW PEO ≥22 wt%
- opioid/salt ≥2.4 wt%
Claims 10–14 (total PEO mass dominance thresholds)
They require combined HMW + LMW PEO to be at least:
- Claim 10: ≥60 wt%
- Claim 11: ≥65 wt%
- Claim 12: ≥80 wt%
- Claim 13: ≥85 wt%
- Claim 14: ≥90 wt%
Practical impact:
If a generic or competitor tablet uses these polymer-heavy formulations, these dependent claims create strong “quantitative infringement hooks.” If a competing design uses substantially less PEO mass, it can fall outside these narrower limitations even if the air-curing process and molecular-weight identity are met.
What additional tablet properties expand claim scope in claims 15–20?
Claims 15–17 (excipients)
- Claim 15: tablet further comprises magnesium stearate
- Claim 16: further comprises butylated hydroxytoluene
- Claim 17: further comprises at least one of:
- lactose
- microcrystalline cellulose
- hydroxypropyl cellulose
These are incremental limitations. Inclusion of these excipients is not required in claim 1.
Claims 18–19 (mechanical robustness and deformation/swelling)
- Claim 18: indentation test thresholds:
- cracking force ≥110 N and/or
- penetration depth to crack distance ≥1.0 mm
- Claim 19:
- tablet can be flattened to ≤60% thickness without breaking
- flattened tablet swells upon exposure to water or ethanol
Practical impact:
These relate to polymer gel/swelling and mechanical integrity of the PEO matrix after molding/curing. They can be used to argue that a competing design has the same material behavior, but they also narrow coverage to formulations that meet specific physical test performance.
Claim 20 (accelerated stability and release deviation)
- After storage at 40°C / 75% RH for ≥3 months:
- USP Apparatus 1 (basket), 100 rpm, 900 mL SGF 37°C (no enzymes)
- no added stabilizer
- release at 1, 4, 12 hours deviates from initial dose amount by ≤ about 10 percentage points
Practical impact:
This is a functional stability/release-performance limitation that can become a key evidentiary battleground in litigation or licensing, because it depends on replicating the same test conditions.
How do claims 21–28 cover curing temperature profiles and convection mean exhaust temperature?
Plateau and profile-shape claims
- Claims 21–22: plateau profile for air temperature during curing.
- Claims 23–24: parabolic or triangular profile for air temperature during curing.
Convection curing measurement method
- Claims 25–28: curing is by convection and air temperature is measured as the mean exhaust temperature of a convection curing device.
Practical impact:
These claims are process-instrumentation centric. A manufacturer that argues its process uses different temperature measurement definitions (e.g., inlet vs exhaust, chamber sensors vs exhaust manifold) may try to design around, depending on how temperature is recorded and mapped to the claimed “mean exhaust temperature.”
How do claims 29–30 use density change to capture the “air-cured shaped tablet” outcome?
- Claim 29:
- cured shaped tablet density is ≥1% lower than the pre-curing shaped tablet
- Claim 30:
- same limitation applied to the claim 4 dependence set
Practical impact:
This is an additional diagnostic feature. It can be used to support equivalence of process effects even when exact polymer behavior or microstructure is harder to compare.
What is the likely claim coverage map against a generic “extended-release opioid + PEO” product?
Infringement likelihood increases when all of the following align
- The opioid is within the claim-2 list (or a claimed salt).
- Tablet is once-daily or twice-daily extended release.
- Matrix uses PEO at ≥54 wt% (HMW) and the HMW PEO corresponds to rheology-based ~4M or ~7M.
- Air curing occurs without compression with heated air ≥62°C for ≥5 minutes, and often within the tighter 65–90°C and duration ranges if asserting dependent claims 3–4.
- If dual matrix is used, it includes LMW PEO (<1M) at the claimed weight floors.
- Optionally, physical and stability limitations (claims 18–20, 29–30) are met.
Primary design-around levers
- Use HMW PEO with a rheology-defined molecular weight outside ~4M / ~7M selections.
- Use a polymer system that does not meet the ≥54 wt% HMW PEO dominance or fails the LMW floors.
- Adjust air curing so the heated-air temperature and time fall outside the defined ranges.
- Change how temperature is measured such that it is not “mean exhaust temperature” during convection (only relevant if the claim asserted is the convection-measurement dependent claim set).
- Reduce PEO mass such that combined polymer wt% fails claims 10–14.
- Achieve acceptable product performance without meeting the specific mechanical indentation and swelling test thresholds.
US patent landscape: what patents typically surround this kind of technology (and where infringement fights usually concentrate)?
US 9,492,391 is the kind of formulation/process claim that tends to sit in a crowded neighborhood of related IP buckets:
- Opioid extended-release tablets using PEO (or PEO-based swellable matrices)
- Methods of making air-cured or thermally cured compression-molded tablets
- PEO molecular weight selection and rheology-defined polymer grades
- Dual-matrix architectures (HMW-driven gel layer plus LMW for porosity/erosion modulation)
- Mechanical integrity and swelling/flattening behavior tied to PEO matrix microstructure
- Release and stability performance tests (SGF, Apparatus 1, timepoint release deviation)
Where litigation risk typically concentrates for this patent family:
- Process proof: curing device settings, air temperature measurement definitions, and “without compression” handling.
- Polymer identity: establishing that the used PEO grades match the claimed rheological molecular-weight assignments (approximate MW ~4M or ~7M).
- Weight accounting: showing wt% of HMW and LMW PEO in the uncoated tablet, and whether dual matrix is present.
Is there enough information here to map the full US patent landscape for 9,492,391 (related patents, continuations, assignees, litigation, and Orange Book listings)?
Not enough information is provided to produce a complete, accurate patent landscape. The request requires, at minimum, identification of the patent’s assignee, filing and priority dates, continuation history, claim-set relationships, and any linked FDA Orange Book reference product(s), plus known litigation dockets and Paragraph IV/PGR events. Those are not included in the prompt, so a defensible landscape cannot be compiled.
Key Takeaways
- US 9,492,391 claims a pain-treatment method using air-cured, compression-shaped extended-release opioid tablets.
- Claim 1 is built around heated-air curing parameters (≥62°C for ≥5 min, without compression) and a PEO molecular-weight-restricted design (HMW PEO at ~4,000,000 or ~7,000,000 by rheology).
- The strongest quantitative infringement levers are wt% thresholds: HMW PEO ≥54 wt% of uncoated tablet, and dual-matrix LMW PEO floors plus combined PEO dominance (up to ≥90 wt% in dependent claims).
- Dependent claims add tighter curing windows, convection exhaust temperature measurement, and performance diagnostics (indentation cracking behavior, flattening/swelling, and SGF release after 3-month accelerated storage).
- A full US landscape (related patents, ownership map, litigation, and regulatory alignment) cannot be produced from the information provided.
FAQs
- What happens to claim coverage if the opioid is present but the tablet is not once-daily or twice-daily extended-release?
- Do the molecular-weight limitations for PEO rely on named grades or rheological “approximate molecular weight” assignments?
- How do the density-decrease limitations (≥1%) influence infringement proofs in a bench test?
- Which dependent claims are most sensitive to how curing temperature is instrumented (exhaust vs chamber sensors)?
- If a tablet uses only one matrix (no second LMW PEO matrix), which wt% limitations still matter?
References
None.
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