RE49443 (US) scope and claim analysis: stable injectable noradrenaline low-concentration, low-oxygen, pH-controlled HCl/NaCl solution with storage impurity limits and inert-gas/sterilization process protections
US RE49443 is a US reissue covering a narrow but technically dense family of formulation and process claims directed to stable injectable noradrenaline (and/or salts, including bitartrate) supplied as a very low concentration aqueous solution in which pH is controlled with hydrochloric acid to 3.3 to 3.6, NaCl is the excipient, water is degassed/deaerated (including low oxygen limits), the product is free of preservatives and anti-oxidizing agents (and in some claims, complexing agents), and quality stability is tied to specific degradation/epimerization/impurity thresholds after storage. The dependent claim set then narrows to how the solution is made (inert gas handling, filtration in inert gas current, and optional heat sterilization) and to sterilization modality (filtration-only), plus containerization and storage-defined compositional specs (arterenone and d-noradrenaline and other impurities).
The practical effect is that RE49443 is strongest as a barrier to competitors that would (i) market a low-dose noradrenaline injection within the same formulation space and (ii) use oxygen-management and acid/pH/NaCl choices that preserve stability without preservatives/antioxidants, and (iii) meet the same post-storage impurity profile. The reissue-like structure also indicates the estate is drafted to capture both product-by-composition and product-by-process.
What is the claim scope of US RE49443 for stable injectable noradrenaline solutions?
Core independent claim structure: The “product” claims define a stable injectable noradrenaline solution by a tight combination of:
- Active: noradrenaline (and in separate claim group, pharmaceutically acceptable salts; explicit noradrenaline bitartrate appears later)
- Concentration: 0.04 to 0.2 mg/mL (and narrower about 0.04 mg/mL in specific dependent claims)
- Solvent: degassed/deaerated water
- Excipient: NaCl
- Acid/pH: hydrochloric acid to pH 3.3 to 3.6
- Excipients/additives excluded: no preservatives and no anti-oxidizing agents (and later: no complexing agents in at least one claim set)
- Additional oxygen control: explicit ≤100 ppb oxygen content appears in dependent claims
- Stability/spec after storage: <0.2% arterenone, <0.5% impurities other than arterenone, and <10% d-noradrenaline after 6 months at 25°C
Claim map (high level)
| Claim numbers |
Claim type |
Main defining elements |
| 1 |
Product-by-composition |
Noradrenaline, 0.04–0.2 mg/mL, degassed water, NaCl, HCl, pH 3.3–3.6, no preservatives, no anti-oxidants |
| 2 |
Product-by-process (process steps) |
Dissolution in degassed water, pH adjustment with HCl, inert gas filtration, inert gas distribution, sterilization |
| 3 |
Product-by-composition (oxygen spec) |
Oxygen content ≤100 ppb |
| 4–6 |
Product-by-composition expansion |
Same as claim 1 plus salt/complexing-agen exclusion and explicit oxygen ≤100 ppb dependency |
| 8–9 & 11–12 |
Product-by-composition (storage spec) |
Post 6 months/25°C impurity limits: arterenone, other impurities, d-noradrenaline |
| 12–16 |
Narrowed product + process modality |
Concentration “about 0.04 mg/mL”, sealed container process, sterilization filtration/heat optional |
| 17–21 |
Salt-specific product family |
Noradrenaline bitartrate with same key formulation boundaries + 6-month impurity specs; sterilization filtration optional |
| 22–25 |
Salt-specific narrower embodiment |
Noradrenaline bitartrate “about 0.04 mg/mL” + sealed container process + storage spec + sterilization filtration |
Which specific formulation features are “must-have” limits in RE49443 claims?
1) Concentration boundary (0.04 to 0.2 mg/mL)
- Claim 1 and its near relatives lock in 0.04–0.2 mg/mL noradrenaline (or salt expressed as noradrenaline base).
- Separate embodiments lock in about 0.04 mg/mL, which is narrower and can matter for design-around: staying materially above or below the “about” boundary can affect literal infringement depending on claim construction.
2) Solvent and oxygen management
- “Solvent is degassed or deaerated water” is a direct compositional feature (claim 1 and multiple others).
- The estate also includes an explicit oxygen content limit: ≤100 ppb (claims 3 and 6).
3) pH control using hydrochloric acid
- “pH range 3.3 to 3.6” coupled with “hydrochloric acid” is a defining active/formulation chemistry limitation.
- Competitors using different acidulants to reach the same pH could avoid the “hydrochloric acid” limitation if claims require hydrochloric acid specifically rather than “acid to adjust pH.” RE49443’s language is explicit: hydrochloric acid.
4) Excipient identity
- Excipient is limited to NaCl. Reformulations using different tonicity agents (e.g., glucose, mannitol, phosphate buffers) would not satisfy the NaCl limitation if the claim requires NaCl specifically as the excipient.
5) Exclusion of additives
- Claims explicitly exclude:
- preservatives
- anti-oxidizing agents
- and in claim 4: complexing agents
- This is an important “negative limitation” that narrows the permitted solution recipes.
6) Storage stability/impurity limits tied to specific degradation/epimerization markers
After 6 months at 25°C, the solution composition is required (in those dependent claims) to have:
- <0.2% arterenone
- <0.5% impurities other than arterenone
- <10% d-noradrenaline
- These are framed “based on the weight of noradrenaline base.”
This ties the claim value to a measurable product spec rather than only initial formulation.
How do the inert-gas and sterilization steps in RE49443 constrain process scope?
Several claims turn on how the solution is made and handled, not only what it contains.
Inert gas filtration and distribution
Claim 2 requires:
- Dissolving noradrenaline and NaCl excipient in deoxygenated/degassed water to 0.04–0.20 mg/mL
- Adjusting pH to 3.3–3.6 using HCl
- Filtrating the solution in an inert gas current
- Distributing in an inert gas current
- Sterilizing
Claims 5 and 9/13/15/18/20 add “sealed containers” language and sterilization modality structure, including:
- sterilizing comprises filtrating, optionally by step (c), or heat sterilizing (as drafted in the claim set you provided)
Sterilization modality: filtration vs heat
RE49443 splits embodiments in a way that can matter for design-around:
- Dependent claims specify sterilizing comprises filtrating (e.g., claim 9 and corresponding bitartrate/process dependent claims).
- Other dependent claims explicitly permit heat sterilizing in the broader “process includes sterilizing comprising filtrating optionally… or heat sterilizing.”
In other words:
- If a generic or co-marketer uses a process that departs from inert gas filtration/distribution or uses different sterilization steps, it may fall outside product-by-process coverage even if it matches product composition, depending on how courts treat the “obtained by process” language.
What “nitty-gritty” product-by-process boundaries exist in claims for sealed containers?
Claims 5, 13, and 18 (and corresponding narrower embodiments) add:
- solution is “in one or more sealed containers”
- distribution “into said one or more containers”
- sterilization comprises filtrating (optionally by step (c)) or heat sterilizing
This is relevant because some manufacturing suites may:
- blend and fill in non-inert handling environments
- use open handling prior to fill
- avoid inert gas current during filtration/distribution
Those choices can weaken infringement arguments on the process side.
How do the storage impurity limits (arterenone and d-noradrenaline) define stability coverage?
The dependent claims anchor stability to a discrete shelf-life endpoint:
- “after six months storage at 25°C” the solution has:
- arterenone <0.2%
- impurities other than arterenone <0.5%
- d-noradrenaline <10%
This provides two leverage points in litigation or licensing negotiations:
- Competitors who match initial composition but fail stability specs can be outside the specific dependent claims that enforce the impurity limits.
- A licensee that agrees to production and release specifications can still be attacked if long-term accelerated or real-time stability data do not comply.
From a freedom-to-operate standpoint, the storage spec is a de facto requirement: even if process differs, meeting these thresholds at 6 months at 25°C could still bring a composition into the dependent claim coverage (to the extent courts interpret “wherein, after six months…” as product characteristics, not only process artifacts).
How does RE49443 treat noradrenaline salts versus free base?
RE49443 is drafted to cover:
- “noradrenaline” in claim 1
- “noradrenaline or pharmaceutically acceptable salt thereof” in claim 4
- explicit noradrenaline bitartrate in claims 17–25
The bitartrate subset repeats the same core constraints:
- concentration based on noradrenaline base
- degassed/deaerated water
- NaCl
- pH 3.3–3.6 using HCl
- no preservatives and no anti-oxidizing agents (and the bitartrate set you provided does not repeat the “complexing agents” exclusion clause found in claim 4)
- sealed container process and inert gas steps
- sterilization (filtration-only in some dependents)
- storage impurity limits
Operationally, this means design-arounds that switch salt form are unlikely to avoid coverage unless they:
- use a different salt not within “pharmaceutically acceptable salt thereof” (which is broad), or
- change other defining limitations (NaCl excipient, pH range, HCl acidulant, oxygen limits, or preservative/antioxidant absence).
Does RE49443 include oxygen threshold claims, and how hard is that to design around?
Yes. Claims 3 and 6 include:
- “oxygen content is equal to or lower than 100 ppb”
- and a related claim dependent on claim 4 (or claim 1 family) with solvent oxygen content ≤100 ppb.
These are measurable and can be tested by headspace or solution oxygen measurement methods. A competitor could attempt to:
- remove dissolved oxygen (degassing) and avoid inert atmosphere manufacturing
- but oxygen can re-enter depending on handling and fill conditions.
Because the product claims include degassed/deaerated water and the process claims include inert gas filtration/distribution, combining both can strengthen enforcement.
What does the claim set imply about the practical formulation “operating window”?
Across claims, the intersection of:
- very low noradrenaline concentration (0.04–0.2 mg/mL, with specific embodiments near 0.04 mg/mL)
- aqueous solvent with very low oxygen
- NaCl excipient
- HCl-adjusted pH tightly between 3.3 and 3.6
- absence of preservatives/anti-oxidizing agents (and no complexing agents in at least one salt claim)
defines a narrow “operating window” that likely corresponds to:
- controlling oxidation/degradation (arterenone)
- controlling epimerization to d-noradrenaline
- avoiding interference from preservatives/antioxidants that might change stability or impurity profile.
In enforcement terms, a challenger must address multiple interacting limitations, not only one.
Where are the highest-risk infringement vectors for generics or alternative manufacturers?
-
Product-by-composition match
- same active (or salt), same low concentration range
- same NaCl excipient and HCl to achieve the pH window
- no preservatives and no anti-oxidants
- degassed/deaerated water
-
Oxygen-managed product
- oxygen content ≤100 ppb (if tested and claimed)
- solvent oxygen limit equivalents
-
Product-by-process match
- inert gas current filtration and distribution
- sterile solution produced using those handling steps
- sealed container filling
-
Stability specification match
- meeting post-storage impurity limits (arterenone, other impurities, d-noradrenaline)
The “gotchas” for a competitor are:
- small deviations outside pH or concentration
- using alternative excipients instead of NaCl as the excipient
- using different acidulant for pH adjustment (non-HCl)
- adding antioxidants/preservatives/complexing agents
- failing oxygen targets under routine manufacturing and during fill.
What “design-around” levers exist based on the literal claim elements?
Based on the claim language provided, the most salient levers are:
- pH shift outside 3.3–3.6 (even if close)
- switching from HCl to another acidulant for pH adjustment
- changing excipient from NaCl to another tonicity/ionic strength system
- adding preservatives or anti-oxidizing agents (though this may conflict with stability)
- adding complexing agents (particularly relevant for the claim 4 family)
- bypassing inert gas filtration/distribution steps in manufacturing (process side)
- sterilization method change (filtration-only versus heat-permitted dependents)
- escaping concentration boundaries, especially the narrow “about 0.04 mg/mL” embodiments
However, in practice, these levers can be constrained by the need to reach the same stability endpoints tied to arterenone and d-noradrenaline after storage.
Timeline and exclusivity: what can be concluded from the claim set alone?
Nothing about USPTO grant dates, reissue history, expiration dates, or exclusivity timelines can be derived from the claims text alone. The reissue number (RE49443) signals a reissued patent, but the expiration and exclusivity schedule depends on the underlying application and the specific US patent family members, none of which are provided in the prompt.
Key tables: claim element checklist for infringement assessment
Core element checklist (claims 1 / 12 / 17 / 22 baseline)
| Element |
Requirement (from claims) |
Literal risk if changed |
| Active |
noradrenaline or salt; bitartrate for bitartrate subfamily |
High if different active or salt not covered |
| Concentration |
0.04–0.2 mg/mL (or about 0.04 mg/mL in narrow claims) |
High for dose selection/design-around |
| Solvent |
degassed/deaerated water |
Moderate to high depending on oxygen measurement |
| Excipient |
NaCl |
High if alternate excipient used |
| Acid/pH |
HCl sets pH 3.3–3.6 |
High if alternate acidulant used |
| Preservatives |
absent |
High if any preservative added |
| Anti-oxidants |
absent |
High if any antioxidant system used |
| Complexing agents |
excluded in claim 4 family |
High if complexing agents used |
Process checklist (claims 2 / 5 / 13 / 18)
| Element |
Requirement |
| Dissolve in deoxygenated/degassed water |
yes |
| pH adjustment |
add HCl to 3.3–3.6 |
| Filtration |
in inert gas current |
| Distribution/fill |
in inert gas current into sealed containers (in those claims) |
| Sterilization |
includes filtration and/or heat as stated per dependent claim |
Storage spec checklist (dependent claims)
| Storage condition |
Quality thresholds |
| 6 months at 25°C |
arterenone <0.2% ; other impurities <0.5% ; d-noradrenaline <10% |
What is the practical patent landscape around RE49443 based on claim scope only?
From the claim drafting, the landscape risk clusters into two defensible “pockets”:
- Formulation/product pocket
- narrow composition space defined by concentration, NaCl, HCl pH window, oxygen-managed degassed water, and no preservatives/antioxidants
- Process/product-by-process pocket
- inert gas filtration/distribution and sterilization approach, with sealed container handling
- Stability-spec dependent pocket
- impurity profile after 6 months at 25°C
This typically means:
- alternative manufacturers may be forced to adopt similar oxygen management and acid/pH choices to reproduce the stability outcomes without adding preservatives or antioxidants.
- litigation strategies tend to focus on whether competitors meet the “negative limitations” and whether stability specs are met, supported by COA-style impurity analyses.
Key Takeaways
- RE49443’s claims are built around a very specific noradrenaline injection formulation space: low concentration (0.04–0.2 mg/mL), NaCl excipient, HCl to pH 3.3–3.6, degassed/deaerated water, and no preservatives/anti-oxidizing agents (and no complexing agents in at least one salt claim).
- The estate strengthens enforcement with oxygen thresholds (≤100 ppb) and storage stability specs at 6 months/25°C (arterenone <0.2%, other impurities <0.5%, d-noradrenaline <10%).
- Process claims impose inert gas filtration and distribution and include sealed container language, with sterilization options depending on dependent claim structure.
- Salt switching to bitartrate does not, by itself, avoid coverage because RE49443 includes explicit bitartrate claims and broadly covers “pharmaceutically acceptable salts.”
FAQs
-
Do RE49443 claims cover noradrenaline bitartrate even if the formulation uses the same concentration and pH window?
Yes. Claims 17–25 explicitly cover noradrenaline bitartrate formulations and repeat the key pH, NaCl, HCl, oxygen/degassing, and additive exclusions.
-
Is inert gas handling required to infringe RE49443?
Not for composition claims (e.g., claim 1-family). Inert gas appears in process claims (e.g., claim 2-family and sealed-container process claims), which may matter if only “obtained by a process” claims are asserted.
-
What impurity endpoints are tied to the 6-month stability limitation in RE49443?
Arterenone (<0.2%), other impurities (<0.5% other than arterenone), and d-noradrenaline (<10%) after 6 months at 25°C.
-
Can a competitor avoid RE49443 by adding antioxidants or preservatives?
Based on the claim exclusions, adding preservatives or anti-oxidizing agents would not satisfy at least the “free of” limitations in the core claims and would likely move the product outside the claim scope.
-
Does RE49443 require oxygen content measurement or only degassed water?
The claims include both: general “degassed/deaerated water” requirements and dependent limitations specifying oxygen content ≤100 ppb.
References
- United States Patent RE49443. Claims text provided in prompt (stable injectable noradrenaline solutions; pH 3.3–3.6; NaCl excipient; HCl; degassed water; no preservatives/anti-oxidants; inert-gas filtration/distribution; storage impurity limits).
