|
Patent landscape, scope, and claims: |
US Patent 9,597,402: What Is Claimed and How Broad the Formulation Scope Really Is
US 9,597,402 claims a drug delivery formulation that combines (i) a lactic acid-glycolic acid (PLGA) copolymer with a specific molecular weight window, (ii) a defined organic solvent vehicle that forms a viscous gel, and (iii) risperidone base in a specified particle-size range, yielding a composition for controlled release with an additional “lag time” performance limiter in dependent claim 17.
What are the independent claim 1 building blocks and hard numeric limits?
Independent claim 1 requires all of the following in one formulation:
| Element |
Required definition in claim 1 |
Numeric scope in claim 1 |
| Polymer |
“copolymer of lactic acid and glycolic acid” |
Number average molecular weight (Mn): 1,000 to 120,000 Daltons |
| Vehicle / gel-former solvent |
“organic solvent…selected from” benzyl alcohol, benzyl benzoate, ethyl benzoate, ethyl hydroxide, N-methyl-2-pyrrolidone (NMP), and mixtures |
Vehicle composition ranges |
| Risperidone base form |
“risperidone base in particle form incorporated in the viscous gel” |
Average particle size: 0.1 μm to 125 μm |
| Vehicle weight % (vehicle is copolymer + organic solvent) |
Copolymer fraction in vehicle and solvent fraction in vehicle |
PLGA: 40% to 55% by weight; solvent: 45% to 60% by weight |
Vehicle composition constraint is not additive-free. Claim 1 states copolymer and solvent comprise a vehicle, with copolymer 40-55 wt% and solvent 45-60 wt%. A formulation must satisfy overlap to reach 100% vehicle by weight. Practically, the vehicle is feasible only where those ranges intersect, which is copolymer 40-55 wt% and solvent 45-60 wt%, i.e., copolymer and solvent can jointly sum to 100% within overlap.
Key breadth point: Claim 1’s solvent list is broad in that it includes both aromatic benzoates/benzoic ester solvents and NMP, but narrower than a generic “organic solvent” claim.
How much narrower are the dependent claims?
Dependent claims 2-16 slice claim 1 along four major axes:
- Polymer lactic:glycolic monomer ratio
- Polymer molecular weight subranges
- Specific solvent selection (NMP)
- Risperidone base concentration
- Performance limiter (lag time) in claim 17
Monomer ratio limits (claims 2, 3, 9, 10, 11, 12, 14-16)
| Claim |
Lactic acid : glycolic acid monomer ratio |
Notes |
| 2 |
about 100:0 to 60:40 |
“about” introduces some flexibility |
| 3 |
100:0 to 75:25 |
narrower toward glycolic acid |
| 9 |
about 100:0 to 60:40 + Mn 1,000 to 30,000 |
combined with lower Mn window |
| 10 |
100:0 to 75:25 + Mn 5,000 to 30,000 |
combined with lower Mn window |
| 11 |
about 100:0 to 60:40 + Mn 1,000 to 30,000 + NMP |
combined with solvent selection |
| 12 |
100:0 to 75:25 + Mn 5,000 to 30,000 + NMP |
combined with solvent selection |
| 14 |
about 100:0 to 60:40 + Mn 1,000 to 30,000 + NMP + risperidone 10-30 wt% |
triple restriction |
| 15 |
100:0 to 75:25 + Mn 5,000 to 30,000 + NMP + risperidone 10-30 wt% |
triple restriction |
| 16 |
100:0 to 75:25 + NMP + risperidone 10-30 wt% |
no Mn floor in text beyond claim 1’s general Mn |
Interpretive scope effect: claim 1 allows any lactic:glycolic ratio because it does not state monomer ratio; claims 2 and 3 add ratio constraints and then tie them to Mn ranges in later claims. That means claim 1 is the broadest on monomer composition, while dependent claims narrow it.
Molecular weight subranges (claims 4, 5, 9, 10, 11, 12, 14, 15)
| Claim |
Mn number average molecular weight |
Relationship to claim 1’s 1,000 to 120,000 |
| 4 |
1,000 to 30,000 |
cuts upper bound sharply |
| 5 |
5,000 to 30,000 |
eliminates 1,000 to 5,000 tail |
| 9 |
about 100:0 to 60:40 + 1,000 to 30,000 |
|
| 10 |
100:0 to 75:25 + 5,000 to 30,000 |
|
| 11 |
about 100:0 to 60:40 + 1,000 to 30,000 + NMP |
|
| 12 |
100:0 to 75:25 + 5,000 to 30,000 + NMP |
|
| 14 |
about 100:0 to 60:40 + 1,000 to 30,000 + NMP + risperidone |
|
| 15 |
100:0 to 75:25 + 5,000 to 30,000 + NMP + risperidone |
|
Breadth point: because claim 1 covers Mn up to 120,000, it captures higher-Mn PLGA embodiments that dependent claims may not.
Solvent restriction to NMP (claims 6, 11-13, 14-16)
| Claim |
Solvent requirement |
Included where? |
| 6 |
organic solvent comprises NMP |
claim 6 |
| 11 |
NMP + monomer ratio about 100:0 to 60:40 + Mn 1,000-30,000 |
|
| 12 |
NMP + monomer ratio 100:0 to 75:25 + Mn 5,000-30,000 |
|
| 13 |
NMP + risperidone 10-30 wt% |
|
| 14-16 |
NMP tied to monomer ratio and/or Mn windows plus risperidone |
|
Claim 1 permits multiple solvents; NMP is one member of that set. Dependent claims specifically lock to NMP.
Risperidone base loading (claims 7-8, 13-16)
| Claim |
Risperidone base amount |
Relative scope |
| 7 |
5 wt% to 40 wt% |
widest loading dependent range |
| 8 |
10 wt% to 30 wt% |
mid-range narrowing |
| 13 |
NMP + 10 wt% to 30 wt% |
narrowed and solvent-specific |
| 14-16 |
NMP + 10 wt% to 30 wt% (+ other limits) |
|
Claim 1 itself does not set risperidone loading, so formulation loading is flexible in the independent claim.
What does claim 17 add? Does it limit infringement risk?
Claim 17: “The formulation…exhibits a lag time less than 0.2.”
That is a performance limitation. In practice, it functions as an additional criterion beyond composition. If “lag time” is defined in the patent specification via a test method, it can narrow the claim to formulations that meet that experimental threshold.
Because the claim text you provided does not restate the test definition, the operational risk hinges on the specification’s measurement method. Still, as written, claim 17 requires lag time < 0.2.
Scope Map: Where Claim 1 Covers, and Where Dependent Claims Carve It Up
Core coverage (Claim 1)
A formulation infringes claim 1 if it has:
- PLGA copolymer with Mn 1,000-120,000
- Viscous gel formed using a vehicle solvent from the enumerated list (benzyl alcohol, benzyl benzoate, ethyl benzoate, ethyl hydroxide, NMP, or mixtures)
- Risperidone base particles within 0.1 μm to 125 μm
- Vehicle composition: PLGA 40-55 wt% and solvent 45-60 wt%
Secondary coverage bands (Dependent claims)
Dependent claims 2-3 define monomer ratio bands, 4-5 define Mn subranges, 6 and 11-16 narrow the solvent to NMP, and 7-8 plus 13-16 narrow risperidone loading.
Performance-limited coverage (Claim 17)
Lag time < 0.2 creates a separate practical gating condition.
Patent Landscape Implications (US 9,597,402): What Other Patents Would Typically Block or Overlap
A composition claim like this typically collides with three kinds of prior art:
- PLGA-based risperidone depot formulations (same drug, same delivery architecture)
- PLGA particle sizing and micron-scale drug dispersion in PLGA matrices
- Use of specific PLGA parameters (Mn and lactide:glycolide ratio) and specific solvents to tune viscosity, gelation, and release kinetics
Even without mapping specific family members by number (you provided no citation set or forward/backward references), the numeric structure of claim 1 suggests the patent is targeting a particular formulation “sweet spot” that can be designed around by moving outside one of the hard constraints:
- switching the solvent outside the listed group,
- altering PLGA Mn outside 1,000-120,000 (or using a different polymer),
- altering particle size outside 0.1-125 μm,
- altering vehicle wt% composition outside overlapping 40-55 / 45-60 bands,
- and for claim 17, failing the lag time threshold.
From an enforcement perspective, claim 1’s breadth on risperidone load and monomer ratio likely gives it more room, while dependent claims tighten it further (particularly NMP embodiments with specific Mn windows and 10-30 wt% drug loading).
Key Design-Around Pressure Points
Below are the “most movable” constraints versus “most specific” constraints, based on how claim elements are drafted.
Most specific constraints
- Solvent must be one of the enumerated solvents (benzyl alcohol, benzyl benzoate, ethyl benzoate, ethyl hydroxide, NMP) or mixtures of them.
- Particle size must fall 0.1 μm to 125 μm.
- Vehicle wt% ranges must be satisfied simultaneously: PLGA 40-55 wt% and solvent 45-60 wt%.
More flexible constraints in claim 1
- Risperidone loading: claim 1 does not specify wt%.
- Monomer ratio: claim 1 does not specify lactide:glycolide ratio.
- Lag time: only in claim 17, not claim 1.
Practical Claim Coverage Matrix for Business/R&D Risk Screens
This matrix translates claim elements into binary “pass/fail” design screen factors for a formulation team evaluating infringement risk.
| Screen factor |
Claim basis |
Pass condition (must meet all for claim 1) |
| Polymer Mn |
claim 1 |
1,000 ≤ Mn ≤ 120,000 Da |
| Polymer identity |
claim 1 |
PLGA copolymer (lactic acid + glycolic acid) |
| Solvent selection |
claim 1 |
solvent is in the enumerated list (or mixture of them) |
| Vehicle composition |
claim 1 |
PLGA 40-55 wt% and solvent 45-60 wt% |
| Drug particle size |
claim 1 |
risperidone base 0.1-125 μm |
| Drug concentration |
claim 1 |
not specified; only dependent claims 7-8, 13-16 limit |
| Monomer ratio |
claim 1 |
not specified; dependent claims 2-3 etc. limit |
| Lag time |
claim 17 |
< 0.2 |
Key Takeaways
- US 9,597,402 claim 1 is a composition claim defined by four hard numeric/structural gates: PLGA Mn (1,000-120,000 Da), enumerated solvent list, vehicle wt% (PLGA 40-55 / solvent 45-60), and risperidone base particle size (0.1-125 μm).
- Dependent claims 2-16 narrow coverage by adding lactide:glycolide ratio bands, PLGA Mn subranges (mostly ≤30,000 Da), NMP-specific solvent use, and risperidone loading (10-30 wt% in the NMP set).
- Claim 17 adds a performance criterion: lag time < 0.2, which can further constrain enforceable coverage depending on how lag time is defined and measured in the specification.
- The strongest design-around levers are: (i) solvent identity, (ii) risperidone particle size, and (iii) vehicle wt% composition.
FAQs
-
Is risperidone loading limited in the independent claim?
No. Claim 1 does not specify a risperidone wt% range; those limits appear in dependent claims (e.g., 5-40 wt% and 10-30 wt%).
-
Does claim 1 require N-methyl-2-pyrrolidone (NMP)?
No. NMP is one permitted solvent in the enumerated solvent list. NMP is required only in dependent claims that expressly recite it.
-
What is the maximum PLGA molecular weight covered by claim 1?
120,000 Daltons.
-
What particle size range is required for risperidone base in claim 1?
0.1 μm to 125 μm average particle size.
-
What additional condition does claim 17 impose beyond claim 1?
The formulation must exhibit lag time less than 0.2.
References
[1] US Patent 9,597,402 (claims provided in prompt).
More… ↓
⤷ Start Trial
|
