United States Patent 11,154,552: Scope, Claim Boundaries, and US Landscape for an Aripiprazole Prodrug Nanoparticle Composition
What does US 11,154,552 claim, in enforceable scope terms?
US 11,154,552 is directed to aqueous nanoparticle compositions built around an aripiprazole prodrug stabilized with polysorbate 20 (and, in the broader formulation claims, additional formulation excipients). The claims constrain the product by three technical levers:
- Particle size distribution measured as volume-based Dv50 by light scattering
- Surface stabilizer identity and adsorption behavior (polysorbate 20 is required in claim 1; in the formulation set, polysorbate 20 is required as an ingredient and the stabilizer-to-particle ratio is bounded)
- Stabilizer ratio window between aripiprazole prodrug (particles) and polysorbate 20: about 14:1 to about 22:1, with multiple dependent claims narrowing to about 17:1 to about 20:1 and to about 17:1
Core claim architecture (independent vs dependent)
- Claim 1 (composition with adsorption-defined surface stabilizer)
- Requires:
- Aripiprazole prodrug particles with Dv50 between ~175 nm and ~350 nm
- At least one surface stabilizer that has:
- an adsorbed component on particle surface
- a free component available for solubilisation
- Ratio of aripiprazole prodrug to surface stabilizer: ~14:1 to ~22:1
- The prodrug has the recited structural formula (as shown in the claim)
- The surface stabilizer is polysorbate 20
- Claims 2-4 (formulation ingredient set with explicit polysorbate 20 and ratio)
- Require:
- polysorbate 20
- a chelating agent
- a tonicity agent
- an aqueous buffer
- nanoparticle population having recited formula (prodrug structure) and size control
- ratio of said particles to polysorbate 20: ~14:1 to ~22:1
- Size constraints:
- Claim 2: Dv50 between ~175 nm and ~350 nm
- Claim 3: Dv50 < ~350 nm
- Claim 4: particles Dv50 < ~350 nm with polysorbate 20 only (no chelator/tonicity/buffer recited)
- Claims 5-12 (ratio narrowing)
- Narrow ratio range to:
- ~17:1 to ~20:1 (claims 5, 7, 9, 11)
- ~17:1 (claims 6, 8, 10, 12)
- Claims track the different size bins and base claim structures they depend from.
How are the key limitations likely to be read by a court?
The enforceable “center of gravity” is the intersection of particle identity (aripiprazole prodrug), particle size by Dv50, and polysorbate 20 ratio. These limitations are not cosmetic; they operate as gating features that typically drive infringement outcomes at the formulation-product level.
Particle size limit (Dv50, light scattering)
- Claim 1 and claim 2 require Dv50 between about 350 nm and about 175 nm (the ordering in the text is reversed, but the intent is a bounded range).
- Claim 3 and claim 4 require Dv50 less than about 350 nm.
- Dependent claims do not add new size variables; they narrow the ratio.
Practical boundary for infringement analysis
- Products with Dv50 above the upper bound do not meet claims 1/2 and likely do not meet claims 3/4 if “less than about 350 nm” is exceeded.
- Products below the lower bound (below ~175 nm) likely fall outside claims 1/2 and may still fall under claims 3/4 depending on the actual Dv50 and how “less than about 350 nm” is construed.
Ratio of particles to polysorbate 20
Across the independent composition set, the ratio is expressed as:
- Claim 1: ratio of aripiprazole prodrug to surface stabilizer = ~14:1 to ~22:1, with polysorbate 20 as the stabilizer.
- Claims 2-4: ratio of said particles to polysorbate 20 = ~14:1 to ~22:1
Dependent claims set narrower ratio targets:
- ~17:1 to ~20:1 (claims 5, 7, 9, 11)
- ~17:1 (claims 6, 8, 10, 12)
Practical boundary for formulation design
- If a competitor targets non-infringement by shifting the ratio, they must clear not just the broad window but also the narrower windows in dependent claims to avoid landing in a narrowed dependent range.
Surface stabilizer adsorption characterization (claim 1 only)
Claim 1 uniquely adds a functional/structural requirement for the stabilizer:
- it comprises:
- an adsorbed component on the particle surface, and
- a free component available for solubilisation
- and the surface stabilizer is polysorbate 20
Claims 2-4 do not include the explicit adsorption/free-component language, but do require polysorbate 20 and ratio and the full excipient list (for claims 2-3) or partial excipient set (claim 4).
Practical boundary
- If a product uses polysorbate 20 but achieves stabilization via a different mechanism, claim 1’s adsorbed/free-component limitation can create a distinct infringement axis. Claims 2-4 are less mechanism-specific and are more formulation-component and dimension-driven.
What is the “device” of the claims: particle composition around an aripiprazole prodrug
All claims recite nanoparticle populations defined by:
- a prodrug chemical identity via the structural formula shown in the claims, and
- particle size metrics by Dv50 from light scattering.
Claims 2-4 and 5-12 then layer excipients and ratios on top of that nanoparticle population identity.
Claim-by-claim constraint matrix (from the text provided)
| Claim |
Must include polysorbate 20 |
Must include chelator / tonicity / buffer |
Particle size (Dv50 by light scattering) |
Ratio constraint |
| 1 |
Yes (surface stabilizer; also adsorption/free-component wording) |
Not stated |
~175 to ~350 nm |
Prodrug : polysorbate 20 ~14:1 to ~22:1 |
| 2 |
Yes |
Yes (chelating agent, tonicity agent, aqueous buffer) |
~175 to ~350 nm |
Particles : polysorbate 20 ~14:1 to ~22:1 |
| 3 |
Yes |
Yes |
< ~350 nm |
Particles : polysorbate 20 ~14:1 to ~22:1 |
| 4 |
Yes |
Not stated |
< ~350 nm |
Particles : polysorbate 20 ~14:1 to ~22:1 |
| 5 |
Yes |
Not stated |
(depends on claim 1) |
Ratio narrowed to ~17:1 to ~20:1 |
| 6 |
Yes |
Not stated |
(depends on claim 1) |
Ratio narrowed to ~17:1 |
| 7 |
Yes |
Yes (depends on claim 2) |
(depends on claim 2) |
Ratio narrowed to ~17:1 to ~20:1 |
| 8 |
Yes |
Yes (depends on claim 2) |
(depends on claim 2) |
Ratio narrowed to ~17:1 |
| 9 |
Yes |
Yes (depends on claim 3) |
(depends on claim 3) |
Ratio narrowed to ~17:1 to ~20:1 |
| 10 |
Yes |
Yes (depends on claim 3) |
(depends on claim 3) |
Ratio narrowed to ~17:1 |
| 11 |
Yes |
Not stated (depends on claim 4) |
(depends on claim 4) |
Ratio narrowed to ~17:1 to ~20:1 |
| 12 |
Yes |
Not stated (depends on claim 4) |
(depends on claim 4) |
Ratio narrowed to ~17:1 |
Scope implications: where competitors are most likely to collide
Highest collision zone
A product that is:
- an aqueous nanoparticle dispersion comprising the recited aripiprazole prodrug
- stabilized with polysorbate 20
- with Dv50 between ~175 and ~350 nm
- and with a particles-to-polysorbate 20 ratio between ~14:1 and ~22:1
is squarely within claims 1 and 2 (and potentially within dependent claims 5-6 if ratio lands in 17:1-based subranges).
Secondary collision zone (claims 3 and 4)
Even if Dv50 is not within the lower-bounded range, products with:
- Dv50 < ~350 nm
- polysorbate 20
- particles-to-polysorbate 20 ratio ~14:1 to ~22:1
can still fall into claims 3 or 4, depending on whether the full excipient set (claims 2-3 style) is used.
“Ingredient shaving” is not a safe design strategy
Removing chelator/tonicity/buffer:
- may avoid claim 2/3 but not claim 4 (which only requires polysorbate 20, particle size < ~350 nm, and ratio).
Removing polysorbate 20:
- likely avoids the entire claim set.
Moving Dv50 upward above ~350 nm:
- may avoid claims 1-2, and likely claims 3-4 if the “less than about 350 nm” threshold is not met.
Adjusting ratio:
- the dependent claims 5-12 create narrow “traps” at ~17:1 and ~17:1 to ~20:1. Design-around by ratio requires care across the full claim tree.
Claim breadth assessment (based strictly on provided claim text)
- Claim 1 is narrower than claims 2-4 because it includes a mechanism-like adsorption/free-solubilisation constraint plus a particle-size band.
- Claims 2-4 broaden the infringement perimeter by specifying formulation ingredients and size/ratio outcomes rather than stabilizer mechanism.
- Claims 5-12 reduce claim breadth by pinning the ratio to tighter numeric targets, creating a second layer of protection for the likely commercial formulation ranges.
US patent landscape: what cannot be produced from the input
A complete patent landscape requires at least: the patent’s bibliographic data (assignee, filing/priority dates, continuation/multiple listings, related family members), plus citation/claim-reference mapping, and downstream citation checks (US patents, published applications, Orange Book where relevant). None of that is present in the prompt beyond claim text and the identifier “United States Drug Patent 11,154,552.”
Because the required landscape work (family clustering, priority chain analysis, overlaps with other aripiprazole prodrug nanoparticle patents, and assessing freedom-to-operate against cited references) depends on external records that are not provided here, a complete and accurate landscape cannot be generated from the supplied information alone.
Key Takeaways
- US 11,154,552 protects an aqueous nanoparticle composition of an aripiprazole prodrug with Dv50 determined by light scattering and stabilized by polysorbate 20.
- The enforceable numeric gate is the particles-to-polysorbate 20 ratio of ~14:1 to ~22:1, with dependent claims tightening to ~17:1 to ~20:1 and ~17:1.
- Size gates are Dv50 ~175 to ~350 nm (claims 1-2) and Dv50 < ~350 nm (claims 3-4).
- The excipient list is not uniform across claims: chelating agent, tonicity agent, and aqueous buffer are required in claims 2-3 but not in claim 4.
- Without bibliographic and citation data for US 11,154,552, a complete US patent landscape cannot be produced from the prompt.
FAQs
1) What is the main infringement risk driver in US 11,154,552?
Meeting all of the claim’s particle outcome limitations: the aripiprazole prodrug nanoparticle identity, Dv50 by light scattering, and the polysorbate 20 ratio window.
2) Does a product need the full excipient set (chelating agent, tonicity agent, aqueous buffer)?
Not for claim 4. Claims 2 and 3 require chelator/tonicity/buffer; claim 4 does not.
3) What happens if a formulation has Dv50 slightly above 350 nm?
It likely falls outside the Dv50 constraints for claims 1-4 because claim 3 and 4 require Dv50 less than about 350 nm, and claims 1-2 require Dv50 in the ~175 to ~350 nm band.
4) Are polysorbate 20 and the ratio required together?
Yes. Every provided independent claim requires polysorbate 20 and constrains the particle-to-polysorbate 20 ratio to ~14:1 to ~22:1.
5) Do the dependent claims create additional numeric traps?
Yes. Dependent claims tighten the ratio to ~17:1 to ~20:1 and ~17:1, so design-around must avoid those windows as well.
References
[1] US Patent No. 11,154,552, claims 1-12 (as provided in the prompt).
