United States Patent RE43711: Scope, Claim-by-Claim Positioning, and US Landscape

RE43711 is a US reissue with Parkinson’s disease method-of-treatment claims anchored on inhaled pulmonary delivery of levodopa-containing particles with tightly constrained composition and powder performance parameters, plus an optional but claim-explicit carbidopa regimen. The enforceable scope sits at the intersection of: (i) inhalation to the respiratory tract, (ii) levodopa payload dominance (about 90 wt% or more), (iii) low salt content (less than 10 wt% salt; NaCl in embodiments), (iv) a non-reducing sugar (explicitly trehalose in one claim), (v) specific aerodynamic particle size windows (1 to 5 micrometers, with sub-ranges), (vi) low tap density constraints (0.4 g/cm3 or less and narrower), and (vii) optional co-therapy with carbidopa, including timing and administration routes.

What is the core inventive concept claimed in RE43711?

Across claims 1 to 10, and also claims 11 to 24, RE43711 claims a pulmonary delivery system for L-Dopa (levodopa) using particles that are compositionally and physically engineered to improve delivery to the pulmonary system while controlling excipient levels.

The repeated limiting elements are:

Route / site of administration: “administering to the respiratory tract” and “delivered to the pulmonary system.”
Drug load: “about 90 weight percent or more levodopa” (or “particles that include, by weight, about 90 percent or more L-Dopa”).
Salt content cap: “a salt wherein the formulation contains less than 10% by weight of the salt” (and in a NaCl-specific claim, “sodium chloride wherein the formulation contains about 3 percent or less sodium chloride”).
Non-reducing sugar requirement: included with the low-salt, high-levodopa particles (and trehalose specified in one claim).
Powder performance windows (most explicitly in claims 2, 3, 5–7, and 20):
- Tap density: about 0.4 g/cm3 or less, with dependent narrowing to 0.3, 0.2, and 0.1 g/cm3 or less.
- Volume median geometric diameter (VMGD): about 5 micrometers or more.
- Aerodynamic diameter: about 1 micrometer to about 5 micrometers, with dependent windows:
- 1 to 3 micrometers and
- 3 to 5 micrometers.

Separately, claims 11 to 24 extend the method-of-treatment concept by adding carbidopa co-administration and specifying particle composition ratios (levodopa:DPPC:NaCl) and carbidopa timing.

Claim-by-claim scope: what each claim actually covers

Independent claim anchors

Claim 1

A method of treating Parkinson’s disease by administering to the respiratory tract particles containing:

≥ 90 wt% levodopa
salt with < 10 wt% salt
non-reducing sugar
particles are delivered to the pulmonary system.

Scope impact: Broadest composition-wise on aerodynamic and tap density because those are not recited in claim 1. The essential functional constraints are the inhaled route, levodopa dominance, low salt, and presence of non-reducing sugar.

Claim 2

Adds multiple particulate property limitations and tightens composition language:

particles consist essentially of ≥ 90 wt% levodopa
non-reducing sugar and salt (<10 wt%)
tap density ≤ 0.4 g/cm3
VMGD ≥ 5 μm
aerodynamic diameter 1 to 5 μm.

Scope impact: Much narrower enforceability perimeter because physical characterization parameters must be met. “Consist essentially of” limits additional components, raising both design-around and claim-construction relevance.

Claim 8

Similar to claim 1 but with explicit NaCl:

particles include ≥ 90 wt% levodopa
NaCl < 10 wt%
non-reducing sugar
pulmonary delivery.

Scope impact: Narrows the “salt” to NaCl specifically.

Claim 10

A delivery method framed as “delivering an effective amount of L-Dopa”:

particles: ≥ 90% L-Dopa by weight
≤ 10% trehalose
NaCl ≤ 3%
administering via “simultaneous dispersion and inhalation” from a receptacle to a human respiratory tract.

Scope impact: Enforces both excipient percentage ceilings (trehalose upper bound and NaCl upper bound) and a specific administration mechanics phrase (“simultaneous dispersion and inhalation”).

Claim 11

Method of treating Parkinson’s disease comprising:

inhalation of particles to the respiratory tract with:
- sodium chloride and
- ≥ 90 wt% levodopa
plus carbidopa to the patient.

Dependent claims 12 to 24 then specify optional phospholipid inclusion, DPPC, and particle ratios, plus carbidopa administration route and timing.

Scope impact: This claim adds a clinical regimen element (carbidopa) but keeps the particle constraints less detailed than claim 2 on tap density and aerodynamic diameter. Claim 20 reintroduces size/tap parameters as a dependent limitation.

Dependent claim narrowing map

Below is how the dependent claims tighten the perimeter of independent claim 2 and 11.

Aerodynamic and tap density dependent set (claims 3, 5–7, 20)

Claim 3: aerodynamic diameter 1 to 3 μm.
Claim 5: tap density ≤ 0.3 g/cm3.
Claim 6: tap density ≤ 0.2 g/cm3.
Claim 7: tap density ≤ 0.1 g/cm3.
Claim 20: re-states for the carbidopa regimen:
- tap density ≤ 0.4 g/cm3
- VMGD ≥ 5 μm
- aerodynamic diameter 1 to 5 μm.

Scope impact: A powder that meets claim 2 and then meets any of these dependent thresholds is pulled into progressively narrower coverage. If a competitor alters aerodynamic diameter distribution or tap density above these caps, the dependent coverage can drop while independent-level coverage may remain (depending on which independent claim they fall under).

Trehalose dependent set (claim 9)

Claim 9: non-reducing sugar is trehalose.

Scope impact: Only claim 9 is sugar-type explicit. Claims 1/2/8 allow other non-reducing sugars.

Phospholipid and DPPC dependent set (claims 12–14)

Claim 12: particles further comprise a phospholipid.
Claim 13: particles further comprise dipalmitoyl phosphatidylcholine (DPPC).
Claim 14: particles include about:
- 90 wt% levodopa
- 8 wt% DPPC
- 2 wt% sodium chloride.

Scope impact: Claim 14 is a composition ratio “lock-in” that can support strong enforceability against formulations approximating these exact proportions, while claims 12 and 13 cover broader phospholipid/DPPC inclusion.

Carbidopa administration route and timing dependent set (claims 15–23)

Claim 15: carbidopa administered by injection or oral.
Claim 16: carbidopa administered orally.
Claim 17: additionally oral administration of levodopa.
Claim 18: carbidopa orally in combination with oral levodopa.
Claim 21: carbidopa administered before levodopa.
Claim 22: carbidopa administered after levodopa.
Claim 23: carbidopa administered at the same time.

Scope impact: For any inhaled levodopa particle dosing under claim 11, the product regimen with carbidopa can still infringe regardless of whether timing is before, after, or simultaneous, as long as the ordered method conditions match the claim construction. Claims 17 and 18 specifically add oral levodopa co-therapy.

Particle ratio dependent set for full regimen (claim 24)

Claim 24:
- levodopa:DPPC:sodium chloride ratio about 90:8:2
- plus carbidopa.

Scope impact: Tightest “ratio + excipient identity + carbidopa” lock-in among the regimen group.

Where is the enforceable “sweet spot” in the claim set?

RE43711 has two overlapping enforceable zones:

Pulmonary levodopa particle composition and powder performance
Dominated by claims 1, 2, 8, 10, and dependent aerodynamic/tap density limits (claims 3, 5–7, 20).
- Strongest particulate enforceability is where both aerodynamic diameter (1–5 μm) and tap density (≤0.4 g/cm3) are required, with VMGD ≥ 5 μm.
Pulmonary levodopa + carbidopa regimen
Dominated by claims 11–24.
- The regimen element (carbidopa) can narrow infringement in practice, but the dependency structure means many common clinical co-administration patterns remain covered:
  - carbidopa route (injection or oral; also oral)
  - timing (before/after/simultaneous)
  - optional oral levodopa addition (claims 17–18)
- The tightest formulation lock-in is 90:8:2 levodopa:DPPC:NaCl (claims 14 and 24).

How does RE43711 map to likely competitor design-around levers?

Based on the claim language provided, the primary design-around levers are:

Adjust levodopa weight fraction
Claims require “about 90 wt% or more.” Moving below that threshold is a straightforward avoidance route.
Alter salt identity or salt percentage
Claim 1 uses “a salt” with <10 wt% by weight; claim 8 and claim 10 use NaCl with explicit caps (<10 wt% and ≤3 wt% respectively). A formulation with NaCl above those caps may evade the NaCl-explicit claims while still risking the broader “salt” claims.
Remove the non-reducing sugar requirement
Claims 1, 2, 8, and 10 all require a non-reducing sugar presence (and claim 9 specifies trehalose; claim 10 caps trehalose at ≤10 wt%). Removing this component can avoid the sugar-dependent claim family.
Shift aerodynamic diameter and/or tap density above limits
Claim 2 and claim 20 impose:
- aerodynamic diameter 1 to 5 μm
- tap density ≤0.4 g/cm3
- VMGD ≥5 μm
  If a powder fails these powder metrics, the claim 2/3/20 dependent footprint drops.
Avoid “consist essentially of” constraints
Claim 2 uses “particles consist essentially of about 90 wt% or more levodopa,” which can raise disputes about allowable additional components. A competitor can aim to add components that create a “not-essentially” composition argument.
Avoid the DPPC/ratio lock-ins
Claims 14 and 24 require about 8 wt% DPPC and about 2 wt% NaCl along with about 90 wt% levodopa. A competitor can shift ratios or exclude DPPC while relying on claim 12/13 scope only.
Break the carbidopa method regimen
If a therapeutic strategy excludes carbidopa (or fails to administer it in a way matching the claimed “administering carbidopa to the patient” requirement), claims 11–24 are harder to reach.

US patent landscape: what can be inferred from RE43711’s claim structure

The claim set indicates RE43711 is a formulation-and-route centric asset built around powder aerosolization characterization (aerodynamic diameter, VMGD, tap density) plus excipient design rules (levodopa dominance, low salt, non-reducing sugar, and optionally DPPC). That pattern typically indicates an ecosystem of related filings in the same family and adjacent families covering:

inhalable levodopa formulations (high drug loading with stabilizers)
low-salt and sugar-stabilized amorphous or solid-state forms
DPPC-containing pulmonary particles
co-administration methods for carbidopa with inhaled levodopa
device/process claims for “dispersion and inhalation” mechanics (as in claim 10)

However, your prompt does not provide bibliographic identifiers beyond the reissue number, nor does it include the specification, filing history, patent family members, assignee, publication equivalents, or prosecution details. Without those bibliographic anchors and without the text of the specification or the reissue’s front page, a reliable cross-patent citation map (including which patents are truly co-pending, family-related, or blocking in the US) cannot be produced from the claim text alone.

Scope summary table (infringement-relevant limitations)

Limitation category	Claims where required	Hard threshold language in claim text
Parkinson’s disease method	1-3, 8, 11-24	“treating a patient with Parkinson’s disease”
Pulmonary/respiratory route	1-3, 8-11, 19-20, 24	“administering to the respiratory tract” / “delivered to the pulmonary system”
Levodopa load	1,2,8,10,11	“about 90 wt% or more levodopa”
Salt content (general)	1,2	“salt… less than 10% by weight”
NaCl explicit	8	“NaCl in an amount less than 10% by weight of NaCl”
NaCl tight cap	10	“about 3 percent or less sodium chloride”
Non-reducing sugar required	1,2,8	“non-reducing sugar”
Trehalose explicit	9 (and cap in 10)	“non-reducing sugar is trehalose”; “about 10% or less trehalose”
Tap density cap	2,5-7,20	≤0.4 g/cm3 (and narrower ≤0.3/0.2/0.1)
VMGD floor	2,20	“volume median geometric diameter about 5 micrometers or more”
Aerodynamic diameter window	2,3,4,20	1 to 5 μm (with dependent 1-3 and 3-5)
Carbidopa co-therapy	11-24	“administering carbidopa to the patient”
Phospholipid and DPPC	12-14	“phospholipid”; “dipalmitoyl phosphatidylcholine (DPPC)”
DPPC/NaCl/levodopa ratio	14,24	about 90:8:2 levodopa:DPPC:sodium chloride
Carbidopa route	15-16	injection or oral; oral
Carbidopa timing	21-23	before/after/same time vs levodopa
Oral levodopa co-therapy	17-18	oral levodopa; combination with oral levodopa
Process/mechanics (dispersion)	10	“simultaneous dispersion and inhalation”

Key Takeaways

RE43711 enforces inhaled pulmonary levodopa with ≥90 wt% levodopa, low salt (<10 wt%), and a non-reducing sugar; claim scope sharpens materially where tap density ≤0.4 g/cm3, VMGD ≥5 μm, and aerodynamic diameter 1–5 μm are required (claims 2, 3, 4, 5–7, 20).
The most rigid formulation lock-in is ~90 wt% levodopa / 8 wt% DPPC / 2 wt% NaCl combined with carbidopa (claims 14 and 24).
NaCl and trehalose have tighter quantitative caps in separate claims: NaCl ≤3% and trehalose ≤10% in claim 10.
Carbidopa regimen coverage (claims 11–24) is broad across oral vs injection and before/after/simultaneous timing, which raises clinical regimen risks for any inhaled levodopa program that includes carbidopa.

FAQs

1. Which claim set is most sensitive to powder aerosol performance (aerodynamic diameter and tap density)?

Claims 2, 3, 4, 5, 6, 7, and 20. They introduce tap density, VMGD, and aerodynamic diameter constraints.

2. Does RE43711 require trehalose specifically?

No. Claim 9 specifies trehalose, and claim 10 limits trehalose to ≤10 wt%. Claims 1, 2, and 8 require a non-reducing sugar but not necessarily trehalose.

3. How narrow is the DPPC ratio coverage?

It is narrow at the dependent-claim level: claims 14 and 24 use an approximately fixed 90:8:2 ratio of levodopa:DPPC:sodium chloride and require carbidopa.

4. What is the salt limitation footprint across claims?

General “salt” cap: <10 wt% in claims 1 and 2.
NaCl cap: <10 wt% in claim 8.
Tight NaCl cap: ≤3 wt% in claim 10.

5. Is carbidopa optional or required?

It is required for the carbidopa regimen claims 11–24 because they explicitly require “administering carbidopa to the patient.”

References

[1] Claims of US Drug Patent RE43711 (as provided in the prompt).

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Merz	INBRIJA	levodopa	POWDER;INHALATION	209184-001	Dec 21, 2018		RX	Yes	Yes	⤷ Start Trial	⤷ Start Trial				INTERMITTENT TREATMENT OF OFF EPISODES IN PATIENTS WITH PARKINSON'S DISEASE TREATED WITH CARBIDOPA/LEVODOPA BY INHALATION OF LEVODOPA POWDER PARTICLES	⤷ Start Trial
>Applicant	>Tradename	>Generic Name	>Dosage	>NDA	>Approval Date	>TE	>Type	>RLD	>RS	>Patent No.	>Patent Expiration	>Product	>Substance	>Delist Req.	>Patented / Exclusive Use	>Submissiondate

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Australia	2003218307	⤷ Start Trial
Canada	2478980	⤷ Start Trial
Cyprus	1118517	⤷ Start Trial
Denmark	1531798	⤷ Start Trial
Denmark	2630954	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: RE43711

Which drugs does patent RE43711 protect, and when does it expire?

Summary for Patent: RE43711