United States Patent 8,148,356: Scope of Claims and US Patent Landscape
What does US 8,148,356 claim, in plain but claim-accurate terms?
US 8,148,356 claims a specific, stable intravenous (IV) acetylcysteine formulation and, in some claims, a container architecture that protects the product via inert-gas headspace and avoidance of chelating agents. The core claim elements repeat across independent claim 1, dependent claims, and container claims (claims 9 to 14).
Independent-claim structure and key limitations
Claim 1 (composition + container + stability targets)
- Drug substance: acetylcysteine (or pharmaceutically acceptable salts).
- Concentration: 200 to 250 mg/mL.
- Chelating-agent exclusion: composition is free from a chelating agent (or salts).
- Dosage form: suitable for intravenous injection.
- pH window: 6 to 7.
- Container sealing concept: composition is in an airtight container with
- fill volume of the composition
- headspace volume occupied by a pharmaceutically inert gas.
Claim 7 (composition with deaerated water + inert headspace + same chelator exclusion)
- Concentration: 200 to 250 mg/mL
- Solvent: deaerated water
- pH adjustment: pH-adjusting agent to pH 6 to less than 7
- IV-suitable
- free of a chelating agent
- airtight container + inert gas headspace
Claim 8 (wider concentration range)
- Concentration: 200 to 500 mg/mL
- deaerated water
- pH: 6 to less than 7
- IV-suitable, free of chelating agent
- airtight container + inert gas headspace
Claim 9 (container claim: composition + headspace)
- A container comprising:
- aqueous acetylcysteine composition
- 200 to 500 mg/mL
- free of a chelating agent
- pH about 6 to less than 7
- suitable for IV injection
- headspace consisting essentially of a pharmaceutically inert gas
Claim 10
- inert gas specified as nitrogen.
Stability and assay retention claims (functional shelf-life constraints)
- Claim 5: stable at least 12 months at 25°C
- Claim 6: stable at least 6 months at 40°C
- Claim 11: “substantially constant” acetylcysteine amount through at least 3 months
- Claim 12: “substantially constant” amount through at least 12 months
- Claim 13: amount through at least 12 months is at least 99% of original
Chelating agent specificity
- Claim 2 depends from claim 1 and emphasizes no EDTA.
- Claim 14 depends from claim 9 and ties down the chelator as EDTA in the dependent context (the dependent limitation appears to identify EDTA as a relevant excluded chelator).
What is the claim scope likely to cover? (practical formulation design envelope)
US 8,148,356 is drafted to capture a formulation that stays chemically stable under IV conditions while limiting acetylcysteine loss or degradation. The claim scope is bounded by explicit numeric and structural limitations.
1) Concentration envelope
Two overlapping numeric regimes appear:
- 200 to 250 mg/mL: claims 1 and 7
- 200 to 500 mg/mL: claims 8 and 9
2) pH envelope
- Claim 1: pH 6 to 7 (inclusive/exclusive not stated beyond “from 6 to 7”)
- Claims 3, 7, 8, 9: narrow/clarify to from 6 up to less than 7
- Claim 4 specifies pH 6.8
- Claim 9 uses “about 6 to less than 7” (approximate range)
3) Chelation exclusion
- Composition is free from a chelating agent (claim 1).
- Dependent claims highlight EDTA as a key chelating agent within the excluded set:
- Claim 2: contains no EDTA
- Claim 14: the chelating agent is EDTA (in a dependent-claim context related to claim 9’s “free of chelating agent”)
This drafting pattern means a generic “no chelators” design likely falls inside the claim, while any design that uses a chelator that is not “pharmaceutically acceptable” could still be argued as a “chelating agent” unless the patent’s claim construction or prosecution record narrows “chelating agent” beyond EDTA.
4) Oxygen management and container architecture
The claims require:
- airtight container
- headspace volume occupied by pharmaceutically inert gas
- explicit nitrogen in claim 10
- “deaerated water” in claims 7 and 8
Container claim 9 adds “headspace consisting essentially of inert gas,” which typically creates a tighter argument against mixing reactive gases in headspace, even if small amounts are present.
5) Stability performance
The claims include time-temperature stability and assay retention:
- 12 months at 25°C (claim 5)
- 6 months at 40°C (claim 6)
- acetylcysteine content retention “substantially constant” through 3 months and 12 months (claims 11 and 12)
- ≥ 99% of original through 12 months (claim 13)
These are not just references; they are claim limitations. A competitor product outside the stability envelope would be able to argue non-infringement, depending on how the stability is measured and the claim construction of “substantially constant” and “at least 99%.”
What does “inert headspace + deaerated water” do to the landscape?
This patent is positioned around a two-pronged oxygen-control approach:
- Process-level oxygen removal: “deaerated water” (claims 7 and 8).
- Container-level oxygen suppression: inert gas headspace (claims 1, 7, 8, 9) and nitrogen specifically (claim 10).
That combination narrows infringement risk for competitors that use:
- standard water plus inert headspace only, or
- deaerated water plus non-inert headspace, or
- use of chelators (especially EDTA)
It also creates a design-around vector: changing pH, using a chelator, altering inert gas strategy, or changing concentration range. However, the patent’s multiple overlapping claims make partial design changes less likely to fully avoid coverage unless the modification hits a major claim element (concentration, pH, chelator freedom, inert headspace requirement, or container “airtight” requirement).
Which claims are the strongest “breadth anchors”?
From a freedom-to-operate perspective, the claims that combine broad ranges with multiple enabling constraints tend to matter most.
1) Broadest concentration claim
- Claim 8: 200 to 500 mg/mL, pH 6 to less than 7, deaerated water, free of chelating agent, IV-suitable, airtight + inert gas headspace.
2) Broadest container claim
- Claim 9: concentration 200 to 500 mg/mL, pH about 6 to less than 7, IV-suitable, free of chelating agent, headspace “consisting essentially of” inert gas.
3) Narrowest but highly specific embodiment
- Claim 4: pH 6.8.
- Claim 10: inert gas is nitrogen.
These are narrower but valuable in enforcement if a product uses those exact specifications.
Where is the infringement risk concentrated? (by formulation knob)
Below is a practical mapping of claim elements to infringement sensitivity.
| Formulation / packaging knob |
Claim elements impacted |
Where risk concentrates |
| Acetylcysteine concentration |
1: 200-250 mg/mL; 8/9: 200-500 mg/mL |
Products in 200-250 mg/mL are exposed to claims 1/7; products in 200-500 mg/mL are exposed to claims 8/9. |
| pH |
1: 6-7; 7/8/9: 6 to <7; 4: 6.8 |
Most exposure sits in the “pH 6 to <7” region. Exact pH 6.8 increases match likelihood. |
| Chelators |
1: free of chelating agent; 2: no EDTA; 14: EDTA context |
Any use of chelators (especially EDTA) is a likely non-match, subject to claim construction of “chelating agent.” |
| Oxygen management |
7/8: deaerated water; 1/7/8/9: inert gas headspace; 10: nitrogen |
Standard headspace air or CO2 mixes could reduce literal match; fully inert headspace and deaeration increase match. |
| Container “airtight” |
1/7/8 require airtight container |
If packaging does not meet “airtight” limitation, it can be a non-infringement argument even if headspace is inert. |
| Stability performance |
5/6/11/12/13 |
If a challenger product does not maintain assay retention or meets stability thresholds, it can argue non-infringement even if composition matches. |
What is the likely patent landscape around this claim family?
A US patent with this level of specificity (pH window, acetylcysteine concentration, chelator exclusion, inert gas headspace, and stability durations) usually sits in a crowded formulation field where multiple earlier patents exist on:
- acetylcysteine formulations for IV use,
- pH-adjusted aqueous solutions,
- oxidation control (often linked to oxygen exposure),
- container closures and inert atmospheres,
- chelator use or chelator avoidance to manage metal-catalyzed reactions.
However, without the patent bibliographic record, priority data, assignee, and prosecution history, a complete, accurately cited US landscape cannot be constructed from the claim text alone. The claim set provided shows the elements the patent is asserting, but it does not identify which earlier patents it distinguishes over, which family member it is, or which related US continuations/divisionals exist.
Because the request is for a detailed analysis of “scope and claims and patent landscape,” the landscape component must be grounded in identifiable cited documents (family publications, office actions, and related US/NPL patents). That cannot be done using only the claim text you provided.
Key control points for enforcement and invalidity arguments (claim-by-claim leverage)
Even without the file wrapper, the claim drafting implies specific enforcement and defense themes.
Enforcement leverage
- Exact numeric ranges (200-250 mg/mL; 200-500 mg/mL; pH 6 to <7) reduce interpretive ambiguity.
- Exclusion of chelators (including EDTA) is a discrete element that can be tested by formulation records and impurity profiles.
- Headspace requirements and “consisting essentially of” language in claim 9 can drive packaging-specific infringement.
- Stability time-temperature is claim-limited, enabling evidence-driven enforcement.
Likely defense angles
- Stability non-performance: show acetylcysteine content below the defined retention thresholds.
- Different oxygen control strategy: argue container is not “airtight,” or headspace is not inert or not within “consisting essentially of” inert gas.
- Chelator presence or chelator definition dispute: if any chelating species is present (including trace), the factual record matters.
- pH and concentration out-of-range: small formulation shifts can avoid ranges.
Key Takeaways
- US 8,148,356 is a targeted claim set for an IV acetylcysteine aqueous composition with defined concentration and pH limits, no chelating agent (with EDTA highlighted), and a packaging oxygen-control design using airtight containers with inert gas headspace (nitrogen specified in claim 10).
- The most exposed product space is 200 to 500 mg/mL acetylcysteine in pH 6 to <7 formulations that are free of chelators and packaged with inert gas headspace (claims 8 and 9), with additional exposure if deaerated water is used (claims 7 and 8).
- Shelf-life and assay retention limitations (claims 5, 6, 11, 12, 13) provide a measurable boundary that can materially affect infringement outcomes.
- A full US patent landscape analysis requires bibliographic identification and citation-backed mapping; the claim text alone does not support a complete and accurately sourced landscape.
FAQs
-
Does the patent cover acetylcysteine concentrations above 500 mg/mL?
No. The provided claims cover 200-250 mg/mL (claims 1 and 7) and 200-500 mg/mL (claims 8 and 9).
-
Is deaerated water required for every claim?
No. Deaerated water appears in claims 7 and 8, while claim 1 and the container claims focus on inert gas headspace and chelator exclusion.
-
Can a product avoid the patent by using a chelator like EDTA?
The claims require compositions “free from a chelating agent,” and dependent claims emphasize EDTA. A chelator-based formulation is a key design variable to evaluate against the “chelating agent” limitation and any claim construction.
-
What packaging detail is essential to the container claims?
Claim 9 requires headspace consisting essentially of a pharmaceutically inert gas in a container that includes an aqueous acetylcysteine composition meeting concentration, pH, chelator-free, and IV-suitable limitations.
-
What evidence typically decides whether the stability claims are met?
Long-term and accelerated stability and assay data supporting the “stable for at least” time-temperature thresholds and “substantially constant” or “at least 99%” acetylcysteine amount requirements.
References (APA)
[1] United States Patent No. 8,148,356. (Claim text provided by user).
