United States Patent 7,442,388 Scope and Claims: Saturated Phospholipid Pulmonary Particles with Polyvalent Cations
US Drug Patent 7,442,388 claims a temperature-stabilized pulmonary particulate system built around saturated phospholipids + polyvalent cations (typically divalent such as Ca, Mg, Zn) that raise the gel-to-liquid crystal transition temperature (Tg→lc) of the particles by at least 20°C over room temperature (and often ≥40°C). The estate is broad across active agents, particle size/aerodynamics, porosity/hollowness, formulation excipients, and method of making and method of delivering to the respiratory tract. The strongest infringement hooks are the cation/phospholipid molar ratio thresholds and the measured thermal transition delta.
What does US 7,442,388 claim for pulmonary delivery?
Core claim concept: particulate formulations for delivery to the lung where particles contain:
- an active agent
- a saturated phospholipid
- a polyvalent cation
- with a cation:phospholipid molar ratio ≥ 0.05
- and that ratio is “sufficiently high” to increase gel-to-liquid crystal transition temperature such that Tg→lc is ≥ room temperature + 20°C (and in dependent claims, ≥40°C).
Claim structure mapped to practical infringement elements
| Claim element (high-level) |
What the claim requires |
Why it matters in enforcement/DS |
| Pulmonary particulate delivery |
“for delivery to the pulmonary system” and also method claims administering to respiratory tract |
Frames use and product-for-use infringement theory |
| Particle composition |
particles comprising active agent + saturated phospholipid + polyvalent cation |
Establishes formulation identity |
| Ratio threshold |
molar ratio polyvalent cation:phospholipid ≥0.05 |
Bright-line numerical requirement |
| Thermal performance |
Tg→lc higher than same formulation without cation, by ≥20°C |
Performance/measurement claim; key for claim charts |
| Surfactant option |
optional surfactant classes listed |
Expands design-around space if omitted, but still covered if included |
| Size/aerodynamic criteria |
optional but repeated: MMAD <20 µm (often 0.5–5 µm); aerodynamic diameter <10 µm (often 0.5–5 µm) |
Covers inhalation-optimized aerosols |
| Porous/hollow particles |
optional limitation (“hollow and porous”) |
Narrower but common in engineered pulmonary powders |
| Emitted dose metrics |
emitted dose ≥40%, ≥60%, ≥90% |
Links to inhaler performance endpoints |
| Non-aqueous medium / excipients / polymers |
additional optional composition components |
Broadens practical commercial variants |
| Production method |
forming feedstock, adding cation, drying |
Enables method patent coverage beyond product |
Which saturated phospholipids and polyvalent cations are covered?
Saturated phospholipids
- Independent claim language: “saturated phospholipid”
- Dependent examples: natural or synthetic lung surfactant (claim 11), and specific lipids (claims 41, 43):
- Dipalmitoylphosphatidylcholine (DPPC)
- Distearoylphosphatidylcholine (DSPC)
Zwitterionic constraint
- Dependent claims add: “phospholipid is a zwitterionic phospholipid” (claims 53, 54, 55, 59).
Polyvalent cations
- Independent: “polyvalent cation”
- Dependent: “divalent cation” (claim 5 and many follow-ons)
- Exemplars (claims 6, 34, 45, 62–65): calcium, magnesium, zinc
- Example specificity: calcium (claims 9, 34–35, 49–50, 64–65)
Ratio ranges that concentrate claim strength
- At least 0.05 (independent claim 1; claim 26 also expresses ≥0.05)
- 0.05–2.0 (claim 7)
- 0.25–1.0 (claim 8)
- Exemplified: Ca/phospholipid about 0.50 (claims 10, 33, 50, 65)
The numerical ratios create enforceable boundaries when manufacturing can be mapped to measured compositions.
What thermal transition requirement drives novelty and claim coverage?
Measured/defined performance endpoint:
- Particles must exhibit gel-to-liquid crystal transition temperature Tg→lc that is:
- > room temperature by at least 20°C in independent claim 1
- > room temperature by at least 40°C in claim 2 and several corresponding variants (claims 40, 52)
Comparison baseline: independent claim 1 requires that Tg→lc increase is “compared to particles without the polyvalent cation.” That locks in a relative performance requirement.
Storage-temperature variant
- Claim 66 adds: Tg→lc is greater than a storage temperature for the particulate composition by at least 20°C. That matters for real-world stability and for mapping to label/storage conditions.
What particle size and aerosol performance limits are included?
These limitations are optional dependents but repeated, and likely align to inhalation powder requirements.
Particle size claims
- Mass median diameter (MMD): <20 µm (claims 14, 29)
- narrower: 0.5–5 µm (claims 15, 30)
- Aerodynamic diameter: <10 µm (claims 16, 31)
- narrower: 0.5–5 µm (claims 17, 32)
Emitted dose claims
- Emitted dose ≥40% (claim 18)
- Emitted dose ≥60% (claim 19)
- Emitted dose ≥90% (claim 20)
These endpoints likely track powder aerosolization and device compatibility. If a commercial product targets high delivered dose, it increases probability of fitting these dependents.
What active agents are explicitly covered (and how broad is it)?
Claim 12 lists a broad set of active agents and salts:
- nicotine
- human growth hormone
- parathyroid hormone
- leuprolide
- budesonide
- tobramycin
- albuterol
- insulin
- interferon alpha
- interferon beta
- amphotericin
- fluticasone
- salmeterol
- formoterol
- plus salts
The independent claim itself is not limited to those actives in the text you provided, but the explicit list is valuable for freedom-to-operate mapping against known pulmonary drug targets.
What formulation components are included as optional add-ons?
Surfactant (composition dependents)
- Claim 3: surfactant selected from:
- nonionic detergents
- nonionic block copolymers
- ionic surfactants
- Claim 4: specific examples:
- sorbitan esters
- ethoxylated sorbitan esters
- fatty acids, salts
- sugar esters
- ethylene oxides
- combinations
Claim 67 and method-making claim 76 repeat surfactant inclusion as an added feature.
Polymers
- Claim 13 includes: polysaccharides, PVA, PVP, polylactides/polyglycolides, PEG.
- Method claim 77 repeats polymer addition to feedstock.
Excipients
- Claim 22 lists excipients: amino acids, carbohydrates, inorganic and organic salts, carboxylic acids.
- Claim 23 narrows examples:
- hydrophobic amino acids
- monosaccharides/disaccharides/polysaccharides
- sodium citrate, citric acid
- ammonium carbonate, ammonium acetate, ammonium chloride
Method claim 79 repeats excipient addition.
Non-aqueous suspension medium
- Claim 21 adds a non-aqueous suspension medium.
Bulk density
- Claim 24: bulk density < 0.5 g/cm³
- Claim 25: < 0.05 g/cm³
- Method claim 80 repeats bulk density outcome requirement.
What delivery and method-of-use claims exist?
Delivery method claim
- Claim 28: administering to the respiratory tract an effective amount of particles with the specified composition and thermal delta.
Sizing dependent on the method
- Claims 29–32: MMD/aerodynamic size limitations carried into method claims.
Cation ratio and divalent exemplars in method claims
- Claims 33–34: polyvalent cation ratio 0.25–1.0; and divalent cation.
- Claims 35: bulk density limit is included in the method.
- Claim 36: explicit active agent list carried into the method claim.
These method claims support infringement theories for branded instructions and for clinical/companion use of product formulations.
What manufacturing method is claimed?
Method of making temperature stable pulmonary particles (claim 71):
- Form feedstock comprising saturated phospholipid emulsion and active agent
- Add polyvalent cation to feedstock in amount sufficient to provide cation:phospholipid molar ratio ≥0.05 and <2
- Dry to form porous particles with Tg→lc at least ~20°C higher than storage room temperature
Important dependent manufacturing constraints
- Claim 72: cation:phospholipid 0.25–1.0
- Claims 73–75: cation is divalent, selected from Ca/Mg/Zn; exemplary calcium
- Claim 76: optional surfactant added to feedstock
- Claim 77: optional polymer added
- Claim 78: drying yields particle size and aerodynamic diameter limits
- Claim 79: excipient added to feedstock
- Claim 80: drying yields bulk density <0.5 g/cm³
A competitor can avoid product-claims but still face method-claims if it uses the same process parameters and outcomes.
How does claim scope cover porous and hollow particles?
- Claim 37: particles are hollow and porous
- Claim 39 ties hollowness/porosity to claim 26 variant
- Claim 57: hollow particles in a separate dependent sequence
- Method claim 71 expressly targets “drying… to form porous particles”
This is a high-value subset for engineered inhalation powders because porosity aligns with low bulk density and improved aerosolization.
Which independent claim set is likely the “core” infringement anchor?
From the text provided, the likely core anchors are:
- Claim 1: particulate composition with polyvalent cation and Tg→lc delta ≥20°C over room temp; includes gel-liquid transition performance requirement and ratio ≥0.05.
- Claim 26: restates composition with ratio ≥0.05 and Tg→lc delta ≥20°C (more compact)
- Claim 27: porous particles variant with quantitative phospholipid/active ranges (20–99.9% phospholipid; 0.1–80% active)
- Claim 28: method of delivering into respiratory tract with the same composition and thermal delta
The estate, as supplied, appears to be structured around the thermal stabilization mechanism. The dependents then ladder into formulation-specific commercial features.
What are the key design-around levers implied by the claim language?
Because the claims hinge on:
- cation:phospholipid ratio
- Tg→lc delta over room temperature
- pulmonary particle/aerodynamic performance
Design-around typically targets at least one of those three constraints.
Potential carve-out patterns embedded in claim dependencies
- Use phospholipid type different from the “saturated phospholipid” definition, or non-zwitterionic phospholipids (though independent claims are not limited to zwitterionic in your text, dependents are).
- Keep cation:phospholipid ratio below 0.05.
- Use cation amounts that still achieve a gel transition but not ≥20°C over room temperature.
- Achieve stability by different physicochemical mechanisms (not asserted by your provided claims).
- Change particle aerodynamic size so it misses MMAD/aerodynamic limits in dependents (but note independents do not require these limits).
The thermal delta requirement is the hardest constraint to “work around” if the product retains the same compositional logic.
Patent landscape: what can be concluded from the claim set alone?
You provided the claim text, but not the bibliographic metadata (assignee, filing dates, continuation relationships, related patents, or the full specification). Without those, the only landscape statements supported are those deducible from claim breadth and structure:
Landscape implications of breadth
- The claim set is platform-like: it is not limited to one drug or one phospholipid. It spans multiple pulmonary actives and multiple formulation variables.
- This indicates the patent likely covers a technology concept (temperature-stabilized phospholipid particles via polyvalent cation).
- Such estates typically generate companion claims across:
- specific active agents
- specific cations (e.g., calcium)
- specific lipids (DPPC/DSPC)
- specific particle engineering (porous/hollow; low bulk density)
- aerosol performance (MMAD/aerodynamic)
- manufacturing pathways (feedstock + cation addition + drying)
Litigation risk profile
Based solely on claim scope, risk is highest for competitors whose commercial products have:
- saturated phospholipid particle matrices
- divalent cations at or above the threshold ratio
- stability mechanism that raises Tg→lc
- porous/low-bulk density, inhalable particle size distributions
- and/or manufacturing approaches resembling the feedstock + cation addition + drying process
Key claim-to-commercial product mapping checklist
Use this as a practical infringement claim chart structure for any pulmonary powder/particle product:
| Category |
Evidence to collect |
Claim hooks |
| Composition identity |
phospholipid is saturated; active is present; polyvalent cation present |
Independent claim 1; dependents 11, 41, 43 |
| Ratio quantification |
measure molar ratio of cation to phospholipid |
Independent ≥0.05; dependent 0.05–2.0, 0.25–1.0; Ca ≈0.50 |
| Thermal characterization |
Tg→lc measured with and without cation (or comparative evidence) and compared to room temperature |
Independent ≥20°C delta; dependent ≥40°C |
| Particle morphology |
porous/hollow? bulk density? |
claims 37, 39, 57; claims 24–25; method claim 71/80 |
| Aerosol metrics |
MMD and aerodynamic diameter |
claims 14–17; method claims 78 |
| Dose performance |
emitted dose percent |
claims 18–20 |
| Formulation additives |
surfactant/polymers/excipients/suspension medium |
claims 3–4, 13, 21–23 |
| Method evidence |
process conditions for feedstock, cation addition, drying |
claim 71 and dependents 72–80 |
| Use evidence |
respiratory tract administration |
claim 28 and dependents 29–36 |
Key Takeaways
- US 7,442,388 claims pulmonary particulate formulations in which polyvalent cations (often divalent Ca/Mg/Zn) at cation:phospholipid molar ratio ≥0.05 raise the gel-to-liquid crystal transition temperature by ≥20°C over room temperature.
- The estate breadth spans active agents, including nicotine, budesonide, tobramycin, albuterol, insulin, interferons, amphotericin, fluticasone, salmeterol, formoterol, and hormones/peptides in your provided list.
- The most enforceable features are the numerical ratio limits and the thermal performance delta.
- The claim set also covers porous/hollow particles, low bulk density, inhalable particle size/aerodynamic diameter, emitted dose, and a manufacturing method tied to feedstock preparation and drying.
FAQs
1) What is the minimum polyvalent cation to saturated phospholipid molar ratio required by US 7,442,388?
At least 0.05 (independent claim 1; also reflected in claim 26).
2) How much must gel-to-liquid crystal transition temperature increase versus room temperature?
At least 20°C in independent claim 1; at least 40°C in dependent claim 2 and corresponding variants.
3) Does US 7,442,388 cover divalent cations only or any polyvalent cation?
It covers polyvalent cations in independent claims and specifies divalent cations in multiple dependents (Ca/Mg/Zn).
4) What particle sizes are covered for inhalation performance?
Dependents require MMD <20 µm (often 0.5–5 µm) and aerodynamic diameter <10 µm (often 0.5–5 µm).
5) Does the patent include manufacturing-process protection in addition to product claims?
Yes. Claim 71 is a method of making temperature-stable pulmonary particles via feedstock formation, polyvalent cation addition, and drying to achieve the Tg→lc thermal stabilization and porous-particle properties.
References
No patent bibliographic sources were provided in the prompt (court docket, USPTO application data, assignee, publication number, or full patent record). Therefore, no external citations can be compiled from the supplied information.
