Patent Scope and Claims for US Patent 8,808,713 (Formoterol Metered Dose Inhaler Co-Suspension with Phospholipid RSP)
US Patent 8,808,713 claims a metered dose inhaler (MDI) co-suspension for pulmonary delivery of formoterol, built around two-phase particle engineering: respirable active agent particles (AAP) of formoterol (salt/ester/isomer/solvate) and respirable suspending particles (RSP) made of dry particulate phospholipid that is substantially insoluble in the HFA propellant. The core novelty is the controlled co-suspension microstructure: (i) propellant-only suspension medium substantially free of cosolvents/solubilizers, (ii) RSP co-located with AAP in HFA at defined particle ratio ranges up to 200:1, and (iii) RSP engineered for aerodynamic/optical behavior (size distributions, insolubility, optional perforated microstructures made via spray drying using specific lipid/calcium systems).
The claim set is broad in therapeutic and operational language (method-of-treatment for pulmonary diseases; administering via MDI actuation; co-suspension delivery), but the technical boundaries are tight around the inhaler formulation system: phospholipid-based insoluble RSP, specific ratio windows, and optional performance-defined dose/delivery metrics (FEV1 timing and magnitude; delivered dose uniformity; fine particle fraction maintenance through canister emptying).
What does US 8,808,713 claim: composition vs. method vs. process?
What are the independent claim anchors and their claim “center of gravity”?
Claim 1 (composition) is the principal scope anchor. It requires all of the following in a single composition deliverable from an MDI:
- A suspension medium that is substantially free of cosolvents and solubilizing agents and comprises a pharmaceutically acceptable propellant (later dependent claims point to HFA propellants).
- AAP comprising a formoterol salt/ester/isomer/solvate.
- RSP formed separately from the AAP, where the RSP comprise dry particulate phospholipid material that is substantially insoluble in the suspension medium.
- RSP quantity constraints:
- RSP concentration up to ~30 mg/mL.
- Weight ratio (RSP:AAP) above 1:1 up to 200:1.
Claim 2 (method-of-treatment) is a treatment method that incorporates the same co-suspension definition from Claim 1 and adds:
- Providing an MDI containing a co-suspension meeting the particle/RSP constraints.
- Administering by actuating the MDI at least once to deliver a therapeutically effective formoterol dose.
Claim 3 (method for respiratory delivery) is operationally similar to Claim 2, but it frames the activity as respiratory delivery via MDI actuation, again tied to the same co-suspension architecture.
What is claimed as a process in the later dependent claims?
The family includes process language mainly in Claim 37, which claims a co-suspension composition prepared by a process that includes:
- Propellant substantially free of cosolvents/solubilizing agents.
- AAP in crystalline form.
- RSP formed using dry particulate phospholipid that is substantially insoluble in the propellant, and free of the formoterol salt/ester/isomer/solvate.
- Dispersing AAP and RSP into propellant so that RSP:AAP ratio is >1:1 up to 200:1 and RSP co-locate with AAP in the propellant.
This matters for infringement mapping: process language can be leveraged against manufacturing routes (e.g., if an accused product can be shown to meet the same final formulation but makes RSP differently, the “composition by process” boundaries become central).
Which technical features define infringement risk: the “must-have” formulation constraints?
1) “Substantially free” cosolvent/solubilizer propellant medium
Claim 1 requires a suspension medium that is substantially free of cosolvents and solubilizing agents and comprises a propellant. This excludes common MDI co-formulation strategies relying on cosolvents (often used to stabilize drug or tune particle engineering in some systems).
2) Two segregated particle populations: AAP vs RSP
RSP must be:
- formed separately from AAP, and
- contain dry particulate phospholipid that is substantially insoluble in the suspension medium.
AAP must be:
- plurality of respirable particles of formoterol salts/esters/isomers/solvates.
This two-population framework is the structural backbone for claim construction. A formulation that blends lipids into the active particle (rather than discrete RSP) is outside the “separately formed” limitation.
3) Quantitative ratio ceiling/floor and concentration cap
Key numeric limits in Claim 1:
- RSP concentration ≤ ~30 mg/mL
- RSP:AAP weight ratio >1:1 to 200:1
Dependent claims further define narrower windows:
- Claim 27: ratio 10:1 to 200:1
- Claim 28: ratio 15:1 to 60:1
This creates measurable infringement thresholds for product characterization. The claims are written so that the accused product must fall inside defined ratio ranges (at least for the dependent claim fallbacks).
4) Optional particle size performance limitations
Claims include two distinct size descriptor sets:
- Optical diameter thresholds for AAP:
- Claim 7: at least 90% by volume exhibit optical diameter ≤ 5 μm
- Claim 8: at least 50% by volume exhibit optical diameter ≤ 2 μm
- RSP size descriptor options:
- Claim 12: RSP mass median aerodynamic diameter in selected windows (examples include 10 μm–500 nm, 5 μm–750 nm, 1 μm–3 μm).
- Claim 13: RSP volume median optical diameter in windows (0.2–50 μm; 0.5–15 μm; 1.5–10 μm; 2–5 μm)
These provisions function as formulation fingerprint claims. Even if RSP material identity is met, size distributions that fall outside the windows can reduce literal coverage for those dependent claims.
5) Optional “perforated microstructures” and specific spray-dried lipid system
Dependent claims tighten RSP structure:
- Claim 9: RSP comprise perforated microstructures
- Claim 10: perforated microstructures prepared using spray drying
- Claim 11: perforated microstructures comprise 1,2-disteroyl-sn-glycero-3-phosphocholine (DSPC) and calcium chloride
Claim 40–42 repeat the same structural constraints in the composition process context.
This is a classic “fallback ladder” technique: broad claim 1 covers phospholipid RSP generally; narrower dependents cover a specific perforated DSPC/CaCl2 spray-dried microstructure.
What formoterol chemical scope is covered: salts/esters/isomers/solvates?
Which active ingredient forms are in-scope?
Claim 1 includes a broad genus: a formoterol salt, ester, isomer, or solvate.
Dependent claims narrow and exemplify:
- Claim 31: enumerated salt list including multiple inorganic/organic acids.
- Claim 32: formoterol fumarate.
- Claim 33: formoterol fumarate comprising respirable crystalline particles.
Claims 34–36 repeat this same genus-to-fumarate narrowing for the method claims.
Practical scope impact: A generic or competitor using a different formoterol salt form (not covered by the enumerations) could still be captured under the open “salt, ester, isomer, or solvate” language in Claim 1, depending on claim construction. But if infringement strategies rely on dependent claim coverage, the enumerated salt list becomes decisive.
Which performance/delivery limitations appear as dependent method claims?
The independent method claims (2 and 3) require administering via MDI actuation delivering therapeutically effective formoterol. Dependent claims then add functional delivery and clinical endpoints.
FEV1 timing, magnitude, and duration
- Claim 16: clinically significant FEV1 increase within 1 hour or less
- Claim 17: within 0.5 hours or less
- Claim 18: increase 150 mL or greater within 0.5, 1, or 1.5 hours
- Claim 19: includes both FEV1 increase within 0.5 hours or less and persistence for up to 4h, 6h, 8h or more
These are method endpoints, often requiring clinical study evidence and can be difficult to prove in product-to-patient mapping, especially for an infringer who does not align dose and patient population.
Delivered dose uniformity and fine particle fraction retention through canister emptying
- Claim 23: delivered dose uniformity (DDU) thresholds (±30% / ±25% / ±20%) throughout canister emptying.
- Claims 24–26: fine particle fraction retention through emptying within 80%, 90%, 95% of initial fine particle fraction.
These limit the method to products that maintain consistent aerosolization performance across the canister, which can be used to distinguish from competitors whose formulation segregation changes particle emission profile over time.
Dose per actuation ranges
- Claims 4–6 and 20–21: multiple dose windows for formoterol per actuation (e.g., 1–30 μg; 0.5–10 μg; 2–5 μg; 2–10 μg; 5–10 μg; 3–30 μg; and “up to” variants).
These become relevant for alignment with typical marketed dose strengths and for determining whether an accused product’s strength is within the claimed ranges.
What delivery system is required: metered dose inhaler architecture
The claims require a metered dose inhaler with a canister containing the co-suspension (Claim 3 and Claim 37). There is no required actuator type beyond “actuating the MDI” and delivering respirable particles.
That said, the fine particle fraction retention and DDU requirements (Claims 23–26) imply the aerosolization behavior of the specific product, not merely the generic concept of an MDI. This is a key litigation pressure point: an infringer could argue that even if its co-suspension composition matches, its emission dynamics do not satisfy the dependent performance limitations.
How does the RSP “co-suspension” concept map to realistic formulation design choices?
Core claim mechanics: suspending AAP in insoluble phospholipid particulates
The RSP are described as:
- dry particulate phospholipid,
- substantially insoluble in the propellant,
- present at defined ratio and concentration.
This resembles a “co-suspension stabilizing particulate” strategy designed to reduce active particle settling/agglomeration and sustain aerosol quality across canister emptying.
“Co-locate with the AAP”
Claim 37 adds “RSP co-locate with the AAP” in propellant. That phrase is likely to drive testable characterization (e.g., mixing/distribution uniformity or co-emission behavior), which can be decisive for infringement under a process/composition-by-process framing.
What is the likely patent estate strategy: breadth with technical fallback layers?
Even without external family/introduction text, the internal dependent structure shows a clear ladder:
- Genus formulation (Claim 1): phospholipid RSP insoluble; propellant-only medium; ratio up to 200:1; concentration cap.
- Quantitative refinements (Claims 27–30): 10:1 to 200:1; 15:1 to 60:1.
- Aerosol and particle distribution fingerprints (Claims 7–8; 12–13).
- Microstructure fallback (Claims 9–11; 40–42): perforated spray-dried DSPC/CaCl2.
- Clinical/functional method refinements (Claims 16–19; 22).
- Device emission consistency refinements (Claims 23–26).
- Stability and impurity formation constraints (Claims 44–46): stable over 18 months at 5°C and low formation rates under 40°C/75%RH one month tests.
This arrangement is typical of IP designed to survive formulation redesign by keeping a broad “core” claim while offering multiple narrower claim hooks for accused products that do not fully match the core.
Where are stability/impurity constraints, and why do they matter for competitors?
What stability and impurity formation limits are claimed?
Claim 44:
- chemically stable within co-suspension over at least 18 months when stored at 5°C.
Claim 45–46:
- rate of formation of a specific compound:
N-(2-hydroxy-5-(1-(2-hydroxy-5-(1-hydroxy-2-(1-(4-methoxyphenyl)propan-2-ylamino)ethyl)phenylamino)-2-(1-(4-methoxyphenyl)propan-2-ylamino)ethyl)phenyl)acetamide
- Not greater than 0.15% after sealing in canister, tested at 40°C and 75% RH for one month (Claim 45).
- Not greater than 0.5% under same conditions (Claim 46).
Claim 44–46 create additional infringement and design-around leverage beyond simple particle identity. A competitor could attempt to match particle architecture but still fail if their product’s stability/impurity profile exceeds these limits.
Which jurisdictions are implicated?
US-only claim set provided; foreign coverage depends on family
Your prompt provides the US patent number and the claim text, but no jurisdictional family members. The analysis scope therefore stays within US claim interpretation and US infringement triggers (composition/MDI delivery/method claims) based on the provided claim content.
What generic entry risks exist for an MDI formoterol co-suspension built on the claimed RSP system?
The highest risk scenario: direct formulation copying with ratio-in-range RSP
If a competitor introduces an MDI co-suspension that:
- uses a suspension medium substantially free of cosolvents/solubilizers,
- includes discrete RSP phospholipid insoluble in propellant,
- matches RSP concentration and weight ratio windows,
- optionally uses similar AAP size distribution and emission consistency,
then literal infringement exposure under Claim 1 (and method claims 2–3) is high.
Lower risk scenario: shifting out of ratio/insolubility boundary or embedding phospholipid in AAP
Design-arounds likely target:
- out-of-range RSP:AAP weight ratio (below or above windows),
- changing RSP solubility behavior (not “substantially insoluble”),
- making RSP not “separately formed” from AAP (e.g., co-manufacturing or active-carried lipid),
- altering RSP structure away from perforated/spray-dried DSPC/CaCl2 (reducing dependent claim coverage, though Claim 1 may still capture if general phospholipid insoluble RSP is retained).
Litigation posture likely built on characterization evidence
Because many dependent claims rely on measurable particle metrics and canister emptying performance, an evidentiary record would typically revolve around:
- particle size distributions (laser diffraction/optical diameter and impactor aerodynamic sizing),
- co-suspension ratio by mass,
- DDU and fine particle fraction retention over canister depletion,
- stability/impurity formation under accelerated conditions.
Key Takeaways
- US 8,808,713 claims an MDI co-suspension for formoterol where discrete phospholipid-based RSP are engineered to be substantially insoluble in a propellant-only medium and present at defined concentrations and RSP:AAP weight ratios up to 200:1.
- Independent claims are anchored on the formulation architecture (AAP of formoterol + separately formed insoluble phospholipid RSP at specified ratios) and on MDI actuation-based respiratory delivery and treatment methods.
- Dependent claim layers add fallback scope via AAP/RSP particle size distributions, optional perforated spray-dried DSPC/CaCl2 microstructures, and functional performance markers (FEV1 endpoints; DDU and fine particle fraction retention).
- Additional risk for competitors comes from stability and impurity formation rate limits tied to canister storage conditions.
FAQs
1) What RSP:AAP ratios are explicitly claimed in US 8,808,713?
Claim 1 covers above 1:1 up to 200:1; Claim 27 covers 10:1 to 200:1; Claim 28 covers 15:1 to 60:1.
2) Does US 8,808,713 require the phospholipid to be DSPC specifically?
No. DSPC/CaCl2 appears in dependent claims for perforated microstructures (Claims 11 and 42). Claim 1 requires only dry particulate phospholipid insoluble in the suspension medium.
3) Are method claims limited to specific pulmonary diseases?
Dependent Claim 14 lists disease examples including asthma and COPD. Independent Claim 2 broadly covers “pulmonary disease or disorder.”
4) What performance metrics are claimed beyond formulation composition?
FEV1 timing/magnitude (Claims 16–19), inspiratory capacity (Claim 22), delivered dose uniformity (Claim 23), and fine particle fraction retention through canister emptying (Claims 24–26).
5) What stability/impurity constraints are included?
Claims 44–46 require stability over at least 18 months at 5°C and limit formation of a specific impurity under 40°C/75% RH for one month, with thresholds at 0.15% and 0.5%.
References
- US Patent 8,808,713. (Provided claim text in user prompt).
