United States Patent 12,383,493 (Method and Formulation Claims for Long-Acting Risperidone SC): Scope, Claim Breakdown, and US Patent-Ready Landscape
The asserted US Drug Patent 12,383,493 is a long-acting, aqueous-insoluble, biodegradable polymer depot concept for risperidone dosed subcutaneously at ≤once every 21 days, with tightly bounded composition (risperidone concentration, polymer chemistry, polymer ratios, and release metrics) and bounded administration/logistics (syringe volume, injection site, and dosing cadence). The claim set is structured to read on a very specific depot architecture: (i) risperidone at ~250-400 mg/mL in ≤1 mL, (ii) an insoluble mixture of PLA-PEG-PLA triblock plus MeO-PEG-PLA diblock in defined ratio windows, and (iii) an IVR-defined, delayed release profile over days to months, supporting schizophrenia/bipolar treatment. The practical effect for freedom-to-operate is that most generic “same drug, same interval” attempts fail on at least one of three tripwires: polymer identity/structure (triblock + diblock chemistry and repeat unit ranges), polymer ratio windows, and the quantitative release constraints.
What does US Patent 12,383,493 claim for long-acting subcutaneous risperidone?
Core independent claim structure (method + formulation)
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Claim 1 (method): treating a psychiatric disease/disorder in a subject by subcutaneous administration with frequency ≤ once every 21 days of ≤1 mL formulation comprising:
- Risperidone (or pharmaceutically acceptable salt) at ~250-400 mg/mL equivalent risperidone
- Biodegradable triblock copolymer: PLA_v-PEG_w-PLA_x where
- v and x are repeat units 24 to 682
- w is repeat units 4 to 273
- v=x or v≠x
- Biodegradable diblock copolymer: MeO-PEG_y-PLA_z where
- y repeat units 3 to 45
- z repeat units 7 to 327
- Polymer ratio constraints: triblock:diblock is within any of these windows:
- 1:3 to 1:8 or 1:1 to 1:19 or 3:2 to 1:19
- formulation is insoluble in an aqueous environment
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Claim 30 (formulation for use): mirrors Claim 1 composition, limited to ≤1 mL, for use in treating a psychiatric disease/disorder.
Immediate scope takeaway: the patent is not a broad “every-3-week risperidone SC” claim. It is an exacting depot-polymer composition claim tethered to risperidone loading and to quantitative polymer chemistry/ranges and to dosing constraints that support depot behavior.
How do the dependent claims narrow the composition, dosing interval, and release profile?
Dose amount, concentration, and interval (claims 1, 3, 13-15, 22, 23-24)
- ≤ once every 21 days (Claim 1) sets the baseline regimen cadence.
- Risperidone concentration 300-400 mg/mL (Claim 3) narrows from the broader ~250-400 mg/mL range.
- Therapeutic duration windows tied to the method:
- 21-90 days (Claim 13)
- 28-90 days (Claim 14)
- 28-56 days (Claim 15)
- No loading dose / no supplemental oral risperidone (Claim 22): supports “direct-to-depot” initiation.
- At least 6 months (Claim 23) and at least 15 months (Claim 24): supports long-duration use, not just short stabilization.
Active form (Claim 2)
- Risperidone base specifically (Claim 2), narrowing salt coverage.
Polymer mass fractions (claims 4-9)
- Triblock copolymer content: ~3-20% w/w (Claim 4); narrower ~5-15% w/w (Claim 5)
- Diblock copolymer content: ~8-25% w/w (Claim 6); narrower ~10-20% w/w (Claim 7)
- Total polymer (triblock+diblock): ~20-50% w/w (Claim 8); narrower ~20-30% w/w (Claim 9)
Scope implication: even if an infringer matches polymer structures and ratio, it still must hit mass fraction windows to land the narrower dependent claims. Independent Claim 1 does not include explicit mass % limits in the text you provided, but dependent claims add those ranges for layered enforceability.
Solvent and excipient system (claims 10-12)
- Water soluble organic solvent is DMSO (Claim 10)
- Triacetin and/or tripropionin (Claim 11)
- Organic solvent content ~35-55% w/w (Claim 12)
Scope implication: this adds a manufacturing/excipient axis. Substituting away from DMSO or the ester plasticizers can be a design-around route, depending on how strictly formulation insolubility and release are maintained.
Release kinetics and IVR basis (claims 16-20)
- <15 w% cumulatively released at 24 hours (Claim 16)
- ~7-15 w% released at 24 hours (Claim 17)
- ~50-80 w% cumulatively released at 30 days (Claim 18)
- ~70-98 w% cumulatively released at 60 days (Claim 19)
- Cumulative release determined by in vitro release (IVR) method disclosed herein (Claim 20)
Scope implication: this is the single most litigation-relevant narrowing element. Many depot formulations can meet “slow release,” but landing inside the multi-point numeric window across 24 hours, 30 days, and 60 days is hard without the same polymer blend, solvent system, and formulation geometry.
Indication (claim 21)
- Schizophrenia or bipolar disorder (Claim 21)
Administration device and injection sites (claims 25-28, 27-28, 29)
- Single prefilled syringe (PFS) (Claim 25)
- Volume 0.1-0.8 mL (Claim 26)
- Subcutaneous into abdomen (Claim 27)
- Subcutaneous into upper arm (Claim 28)
- Formulation is excisable following administration (Claim 29) (wording suggests post-injection excisable characteristics; in practice this may relate to polymer depot attributes or kit/injection handling)
Scope implication: if a competitor uses a vial-and-syringe approach or injection site exclusions in its label instructions, that can matter for claim application. The independent claim text you provided is “method comprising subcutaneous administering,” so device/site features are at least partly dependent claim enforceability.
How broad is the polymer claim language: are there meaningful degrees of freedom?
Triblock (PLA-PEG-PLA) repeat ranges are wide
- v and x: 24 to 682
- w: 4 to 273
- v equals x or not
This is a large parameter space. However, the combination with diblock repeat ranges and the triblock:diblock polymer ratio plus release endpoints sharply constrains practical coverage.
Diblock (MeO-PEG-PLA) repeat ranges are also wide
Ratio windows are complex and may expand coverage
Claim 1 lists multiple ratio windows:
- 1:3 to 1:8 OR
- 1:1 to 1:19 OR
- 3:2 to 1:19
Depending on how the patent defines “ratio,” these windows can overlap and create larger coverage than a single contiguous range. For claim construction, the “or” structure typically broadens. For engineering, ratio windows become an enforceable target.
What are the key infringement tripwires for competitors designing a non-infringing version?
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Polymer identities and structures
- Must include both a PLA-PEG-PLA triblock and a MeO-PEG-PLA diblock, not just one.
- Must meet the repeat unit ranges in the claim.
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Polymer ratio window
- Triblock:diblock must land in one of the enumerated windows.
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Risperidone loading and small injection volume
- ≤1 mL with ~250-400 mg/mL active.
- Dependent claims further constrain 300-400 mg/mL and device volume 0.1-0.8 mL.
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Release profile numeric constraints
- Cumulative release at 24 hours, 30 days, and 60 days must meet the exact numeric windows (and IVR methodology).
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Solvent and plasticizer system
- DMSO and triacetin/tripropionin are included in dependent claims; changing excipients can avoid those dependents, but may still infringe claim 1 if the excipient substitutions do not avoid claim 1’s composition limitations and release endpoints.
What prior-art and landscape elements typically surround this type of claim?
This patent sits in a crowded area: long-acting injectable antipsychotics and polymer depot delivery systems. The claim ties together (i) risperidone depot delivery, (ii) polymer blend design (triblock + diblock), and (iii) release-time numeric endpoints. In such estates, prior art generally falls into three categories:
- Risperidone long-acting injectables with depot polymers and extended dosing intervals
- PLA-PEG-PLA and MeO-PEG-PLA polymer families used for insoluble depot formulations
- IVR-linked release specifications that correlate polymer blends to release profiles
Even without the cited list for US 12,383,493 in your prompt, the practical landscape expectation is that prosecution likely distinguished earlier depot disclosures by combination of polymer blend chemistry, specific repeat ranges, specific solvent/plasticizer, specific dose constraints, and specific multi-timepoint release behavior.
How does US Patent 12,383,493 compare with existing long-acting risperidone products (generic risk lens)?
Risk profile depends on whether the competitor can match the depot blueprint
For generic entry, “therapeutically equivalent” alone is not the legal test. Under US practice, the relevant question is whether a proposed generic or biosimilar-like substitution (though risperidone is small molecule) practices the claimed method/formulation features.
Design-around levers for a prospective generic:
- Change polymer system away from the exact triblock + diblock blend structure
- Use different polymer ratios
- Use different solvent/plasticizer system and accept different release kinetics
- Change dosing volume (if it becomes >1 mL or out of the 0.1-0.8 mL dependent window)
- Change initiation strategy (loading dose vs “absence of loading dose” dependent claim)
Business interpretation: the most meaningful competitive threat is not a “switch manufacturer of same drug,” but a candidate that can match the blend chemistry and release endpoints closely enough to land inside claim 1. That level of similarity tends to require reformulation work plus analytical release matching.
When does exclusivity or patent expiration matter for timing a launch strategy?
Your prompt provides the claim text for US Patent 12,383,493 but does not provide:
- the patent filing date,
- issuance date,
- or any terminal disclaimer terms,
- or any FDA Orange Book listing tied to the patent.
Without those, a defensible exclusivity timeline for US market is not computable from the claim text alone.
What does the claims architecture imply for litigation: method vs formulation enforceability?
Two parallel paths
- Method claim (Claim 1): a claimant must show subcutaneous administration with ≤21-day frequency and performance of the claimed formulation behavior.
- Formulation claim (Claim 30): targets formulation for use. This can be more straightforward for proving infringement because the formulation itself is claimed, independent of how a prescriber chooses to sequence therapy (though “for use” still ties to the intended therapeutic purpose).
Manufacturing proof will focus on
- polymer identity (triblock/diblock type)
- repeat unit distributions (as claimed)
- polymer mass fractions and ratio
- risperidone concentration in ≤1 mL
- solvent/plasticizers
- insolubility in aqueous environment
- IVR release profile at defined timepoints using the disclosed IVR method
Common evidentiary pressure points
- batch release data mapping to the claim timepoints (24 hours, 30 days, 60 days)
- analytical characterization of polymer repeat units and composition
- formulation manufacturing records showing DMSO and triacetin/tripropionin amounts where dependents are asserted
What is the practical patent estate scope for US 12,383,493?
From the claim content alone, the patent scope is concentrated on:
- a single risperidone molecule (and salts, with a dependent base limitation)
- a single route (subcutaneous)
- a single dosing cadence (≤21-day maximum interval)
- a single injection volume ceiling (≤1 mL)
- a single depot polymer blend architecture (PLA-PEG-PLA triblock + MeO-PEG-PLA diblock) with broad-but-bounded repeat ranges
- a solvent/plasticizer build (DMSO plus triacetin/tripropionin dependently)
- an IVR-linked release specification with multi-timepoint numeric constraints
- device/site dependent limitations (PFS, volume window, abdomen/upper arm)
Enforcement strategy inference: this claim set is set up to be asserted against candidates that make the “same kind of depot” rather than just the same active and dosing interval.
Key Takeaways
- US Patent 12,383,493 claims a highly specific subcutaneous long-acting risperidone depot formulation and method: ≤1 mL, risperidone at ~250-400 mg/mL, and an aqueous-insoluble biodegradable blend of PLA-PEG-PLA triblock plus MeO-PEG-PLA diblock.
- The composition scope is constrained by repeat-unit ranges, triblock:diblock ratio windows, and (via dependents) polymer mass fractions plus DMSO/triacetin/tripropionin.
- The enforcement core is the numeric IVR release profile: ~7-15% at 24 hours, ~50-80% at 30 days, and ~70-98% at 60 days.
- A meaningful design-around must change at least one of the three tripwires: polymer blend chemistry/ratio, loading and volume, or IVR release matching.
FAQs
1) What makes a risperidone depot likely to infringe claim 1 of US 12,383,493?
Matching the specific depot blueprint: PLA-PEG-PLA triblock plus MeO-PEG-PLA diblock with claimed repeat ranges, claimed ratio window, risperidone concentration ~250-400 mg/mL in ≤1 mL, aqueous insolubility, and IVR release within the claimed numeric profile.
2) Can a competitor avoid infringement by omitting DMSO or changing triacetin/tripropionin?
It can reduce risk against dependent claims 10-12, but does not avoid claim 1 if the formulation still meets claim 1 composition constraints and achieves the claimed release behavior.
3) How important is injection frequency “no more than once every 21 days”?
High for method claim application. A regimen that exceeds the ≤21-day maximum can avoid claim 1’s method limitation, but formulation claim 30 can still be asserted if it is “for use” under the claimed conditions.
4) What parameter is most likely to create factual dispute in litigation?
The IVR release behavior at the specific multi-timepoint windows, tied to the patent’s disclosed IVR method.
5) Does using a vial instead of a prefilled syringe avoid the patent?
It can help with dependent claims tied to a single PFS and syringe volume, but it does not avoid claim 1 unless device features are treated as limiting in claim construction and unless the formulation still falls within claim 1 composition and method limitations.
References
- United States Patent 12,383,493, “Method of treating a psychiatric disease or disorder … subcutaneously administering … risperidone … biodegradable triblock copolymer … biodegradable diblock copolymer … insoluble in an aqueous environment,” claims as provided in prompt.
