US Patent 11,452,721: Scope, Claim-by-Claim Analysis, and US Landscape for 34 mg Pimavanserin Tartrate Capsules
US 11,452,721 claims a narrow, formulation-and-process-adjacent product: a pharmaceutically acceptable capsule (size 3 or 4) for oral delivery of 34 mg pimavanserin using a blend of pimavanserin tartrate granules (granules containing 40 mg pimavanserin tartrate) with specified granule bulk density and particle size constraints. The dependent claims steer the formulation toward specific excipient classes and specific D90 and bulk density windows.
What is the invention focus and what does it cover?
Core claim theme
The independent claim (claim 1) defines a capsule product by three measurable, technical limitations:
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Dosage and drug form logic
- Capsule is for “orally delivering 34 mg of pimavanserin.”
- Capsule contains a blended pimavanserin composition with granules comprising 40 mg pimavanserin tartrate (with optional excipients).
-
Capsule shell dimensional constraint
- Capsule shell size is 3 or 4.
-
Granules have a high bulk density
- Bulk density of the granules is >0.4 g/mL, determined by USP <616> method 1.
A further claim (claim 3) adds a particle size distribution requirement:
- D90 = 60 to 450 μm measured by laser scattering particle size analysis.
What this means commercially
The patent is not a broad “pimavanserin capsule” patent. It is a manufacturable capsule-formulation construct with:
- a tight granule density threshold,
- a defined drug salt quantity per composition (40 mg tartrate corresponding to 34 mg pimavanserin),
- optional but claim-anchored excipient identities, and
- an optional D90 range that can materially separate formulations.
This structure typically creates strong infringement pressure on products that match the same granulation/bulk density and particle size windows, and weaker reach into formulations that change density, granulation method, or particle size outside the recited windows.
Claim 1: What exactly is protected?
Claim 1 elements (all required)
A capsule for orally delivering 34 mg pimavanserin, where:
- Capsule shell size: 3 or 4
- Contains a blended pimavanserin composition comprising:
- Granules comprising 40 mg pimavanserin tartrate and optionally excipients
- One or more blending excipients
- Granule bulk density: >0.4 g/mL as determined by USP <616>, method 1
- Uses “pharmaceutically acceptable” framing.
Practical scope implications
- If a competitor’s product uses different tartrate loading, different granulation mass balance, or results in granules with bulk density ≤ 0.4 g/mL (under USP <616> method 1), the claim 1 reading can fail.
- If the competitor uses capsule shells outside size 3 or 4, claim 1 does not read.
Landscape note on measurement
Because the claim ties to USP <616> method 1, infringement arguments can hinge on:
- how bulk density is measured,
- whether the measured granule fraction corresponds to the claimed “granules comprising 40 mg pimavanserin tartrate,” and
- which granule batch is tested (blend granules vs. isolated granules).
The D90 limitation in claim 3 gives a second measurement anchor.
Claim 2: How do the excipient identities narrow scope?
Claim 2 depends from claim 1 and limits “one of the blending excipients” to:
- magnesium stearate
- sodium stearyl fumarate
- colloidal silicon dioxide
- talc
How this affects design-arounds
- If a product matches claim 1’s density, capsule size, and drug tartrate loading, but substitutes all of the blending excipients away from these listed materials, claim 2 may not read.
- However, claim 2 is not the independent anchor; claim 1 remains potentially available.
Claim 3: What does the D90 window do?
Claim 3 depends from claim 1 and adds:
- Blended composition has D90 particle size distribution of 60 to 450 μm by laser scattering particle size analysis.
Scope impact
- A particle size shift can move products outside the D90 window even when bulk density stays within or above 0.4 g/mL.
- If a competitor uses milling, sieving, spray drying, agglomeration, or wet granulation conditions to tune D90, claim 3 gives a more binary separation.
Claim 4: What is the capsule form limitation and how does it differ from claim 1?
Claim 4 depends from claim 1 but re-frames the capsule structure:
- Capsule shell size 3 or 4 that encapsulates a blended pimavanserin composition with:
- granules comprising 40 mg pimavanserin tartrate and one or more pharmaceutically acceptable excipients
- bulk density >0.4 g/mL (USP <616>, method 1)
Practical differences vs claim 1
Functionally, claim 4 repeats most of claim 1 but emphasizes the capsule shell encapsulation of a specific blended granulate content. The independent claim 1 already covers the capsule containing the composition; claim 4 strengthens the “encapsulates” product structure language.
Claim 5: What does “hard shell size 4” mean for enforcement?
Claim 5 depends from claim 4 and narrows:
- capsule shell is a hard shell size 4 capsule.
This does not cover size 3 hard shells, and it does not cover softgel types. It narrows the protected product set further.
Claim 6-8: How the excipient classes create a ladder of coverage
Claim 6 (dependent from claim 1)
One blending excipient is selected from:
- cellulose
- polysaccharide
- polyvinylpyrrolidone
Claim 7 (dependent from claim 1)
One blending excipient is selected from:
- microcrystalline cellulose
- silicified microcrystalline cellulose
- hydroxypropyl cellulose
- hydroxypropylmethyl cellulose
- hydroxymethyl cellulose
- lactose cellulose blend
Claim 8 (dependent from claim 1)
One blending excipient is selected from:
- sucrose
- mannitol
- sorbitol
- pregelatinized starch
- partially pregelatinized starch
Ladder effect
These claims create a covering set of common capsule excipients used in granulation and blending:
- cellulose and PVP families appear repeatedly,
- lactose/cellulose blends are explicitly called out,
- sugar alcohols and starch variants are explicitly called out.
In infringement analysis, these dependent claims typically matter when claim 1 is close but not decisive on granule density or D90. They also matter where product characterization identifies one of these excipient identities in the blending excipient portion.
Claim 9-10: What do the combination and functional categories do?
Claim 9 (dependent from claim 1)
Blending excipients comprise:
- microcrystalline cellulose and magnesium stearate
Claim 10 (dependent from claim 1)
Blending excipients are selected from:
- filler/diluents
- lubricants
- mixtures thereof
Interpretation note
Claim 10 is broader than the enumerated excipient list claims (2, 6-9, 11-13). It is functional category based and can read on products whose excipients fall into filler/diluent and lubricant classes, even if they are not explicitly enumerated in earlier dependent claims.
Claim 11-13: Binder excipient narrowing
Claim 11 (dependent from claim 1)
Granules comprise a pharmaceutically acceptable excipient that is a binder.
Claim 12 (dependent from claim 10)
Binder is selected from:
- cellulose
- methyl cellulose
- polyvinylpyrrolidone
- polyethylene glycol
Claim 13 (dependent from claim 4)
Granule excipients comprise a binder.
Coverage implication
These claims focus on granules (not blending excipients). That distinction matters for infringement because many capsule manufacturing processes use:
- binder in granulation,
- disintegrants and fillers in granules,
- lubricants in final blending.
If a competitor’s process uses binders outside the enumerated set in claim 12, claim 12 may not read, but claim 11/13 can still read if any binder is present that meets “binder” characterization under claim construction.
What is the likely infringement-critical feature set?
From the claim set provided, the most likely “infringement-critical” features are:
- Capsule shell size 3 or 4
- Target dose framing: delivering 34 mg pimavanserin
- Granules contain 40 mg pimavanserin tartrate within the composition
- Granule bulk density: >0.4 g/mL by USP <616>, method 1
- Optional but important:
- D90 60 to 450 μm by laser scattering
- Specific blending excipients (Mg stearate, talc, SiO2, etc.)
- Specific binder set (cellulose, methyl cellulose, PVP, PEG)
In practice, bulk density and D90 are quantitative constraints that can materially separate formulations.
How does this claim structure affect patent landscape positioning in the US?
1) This patent is “formulation measurement anchored”
The inclusion of USP <616> method 1 and the laser scattering D90 range makes the patent more difficult to avoid via generic substitution, unless the formulation changes measurably.
2) It is not a broad salt-crystal patent
The claim is not framed as a polymorph, crystal form, morphology, or specific manufacturing step with process recitals. The protection is built around:
- dosage alignment,
- capsule size,
- granule density,
- and particle size.
So, the landscape impact is strongest against products that match this formulation profile, not against products that use the same drug but present substantially different particulate properties or granulation bulk density.
3) Dependent claims create multiple “paths” to infringement
A competitor might avoid one dependent claim by changing excipients, but still fall under independent claim 1 if density and loading match. Conversely, they might miss claim 1 on density but match on excipient identities; that is typically less relevant if claim 1 fails.
Design-around levers suggested by the claim text (actionable scope boundaries)
These are levers implied directly by the claim limitations:
- Move capsule shell outside size 3 or 4.
- Adjust granule composition so the tested granules do not show bulk density >0.4 g/mL under USP <616>, method 1.
- Modify particle size distribution so D90 is outside 60-450 μm (claim 3).
- Replace all blending excipients with materials outside the enumerated sets in claims 2, 6-9, while also ensuring claim 1 reading fails or remains contested.
- Use binder excipients outside the set in claim 12 if you are targeting dependent claim 12 avoidance (though claim 11 and 13 still require only “a binder”).
These levers are not process instructions; they are product characterization boundaries derived from claim constraints.
Key Takeaways
- US 11,452,721 protects a 34 mg pimavanserin capsule with capsule shell size 3 or 4 and a composition built from granules containing 40 mg pimavanserin tartrate.
- The claim’s technical gate is granule bulk density >0.4 g/mL per USP <616> method 1.
- Dependent claim 3 adds an enforceable particle size window: D90 = 60-450 μm via laser scattering.
- Dependent claims then layer excipient and binder identities (or functional categories), creating multiple enforcement routes through product characterization.
- The landscape position is best described as formulation measurement anchored, limiting reach to products that match the quantified granule density and (if asserted) particle size constraints.
FAQs
1) What is the key quantitative limitation in claim 1?
Granule bulk density must be >0.4 g/mL as determined by USP <616>, method 1.
2) Does the patent require a specific capsule type beyond size?
Claim 5 narrows to a hard shell size 4 capsule, but claim 1 broadly requires only capsule shell size 3 or 4.
3) How does claim 3 narrow the protected composition?
Claim 3 requires the blended composition to have D90 of 60-450 μm measured by laser scattering.
4) Are the listed excipients mandatory in every claim?
No. The enumerated excipients in claims 2, 6-9 are in dependent claims. Claim 1 is broader and only requires “one or more blending excipients,” plus the density and composition constraints.
5) Where does the binder show up in the claim set?
Binder appears in granules (claims 11-13). Claim 12 also limits the binder selection to cellulose, methyl cellulose, PVP, or PEG.
References (APA)
[1] USP. (n.d.). USP <616> Bulk Density (and/or related measures), method 1. United States Pharmacopeia.
