Details for Patent: 6,124,261

Summary for Patent: 6,124,261

Title:	Non-aqueous polar aprotic peptide formulations
Abstract:	This invention relates to stable non-aqueous polar aprotic formulations of peptide compounds. These stable formulations comprise peptide in non-aqueous polar aprotic solvent. They may be stored at elevated temperatures for long periods of time and are especially useful in implantable delivery devices for long term delivery of drug.
Inventor(s):	Cynthia L. Stevenson, Steven J. Prestrelski
Assignee:	Horatio Washington Depot Technologies LLC
Application Number:	US09/293,839
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for patent 6,124,261
Patent Claim Types: see list of patent claims	Formulation; Compound; Delivery; Device;

United States Patent 6,124,261: Scope, Claim Strength, and U.S. Landscape

United States Patent 6,124,261 claims a stable non-aqueous peptide formulation using a polar aprotic solvent selected from DMSO or DMF, with added functional limitations around irradiation stability, water exclusion, anti-microbial activity without conventional agents, and delivery via implantable devices. Claim scope is concentrated on formulation composition (DMSO/DMF) plus specific stability and functional performance targets.

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What is the core claim scope (independent claim theme)?

Across the claim set you provided, the independent claim concept is repeated in multiple dependent layers:

Formulation backbone (claims 1–4 and dependent fall-through to 5–41)

Each formulation is defined as:

1) At least one peptide compound
2) At least one polar aprotic solvent
3) Polar aprotic solvent is selected from the group consisting of DMSO and DMF
4) Added constraints in specific claims include:

• Stable after irradiation (claims 2, 12, 31)
• No components containing added water (claim 3)
• Bacteriostatic/bactericidal/sporicidal activity without conventional antimicrobial agent, where the peptide is an LHRH-related compound (claim 4)

Quantitative peptide loading limitations

The formulation scope narrows further by specifying minimum peptide concentrations:

• At least about 10% (w/w) peptide (claims 5, 14, 23, 33)
• At least about 30% (w/w) peptide (claims 6, 15, 25, 34)

Thermal stability windows

The formulation scope also includes explicit stability conditions:

• Stable at 80° C. for at least 2 months (claims 7, 16, 26, 35)
• Stable at 37° C. for at least 3 months (claims 8, 17, 27, 36)
• Stable at 37° C. for at least one year (claims 9, 18, 28, 37)

Delivery form factor

• Adapted for use in an implantable drug delivery device (claims 10, 19, 28, 38)
  • Note: you list claim 28 as an “implantable” dependent from claim 3, and claim 38 as implantable dependent from claim 4.

Anti-gellant effect

• Polar aprotic solvent provides an anti-gellant effect (claims 11, 21)
  • Notably, no equivalent anti-gellant dependency appears for claim 3/4 in the text you provided.

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How broad is “peptide compound” in practice?

The claims use “at least one peptide compound” without structural or sequence specificity in claims 1–3 and the general dependents (5–3x). That creates breadth in principle, because the solvent requirement (DMSO/DMF) is the dominant composition anchor.

However, breadth is reduced sharply when claim 4 is invoked:

• LHRH-related compound is required for the antimicrobial/function limitation in claim 4 and its dependents (claims 13, 22, 32 map the LHRH relevance inside the overall dependent structure you provided).

So the scope splits into:

• Wide universe: “any peptide compound” paired with DMSO/DMF and stability constraints (depending on which dependent claim is asserted).
• Narrow universe: LHRH-related peptides when enforcing antimicrobial performance without conventional agents.

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What does the DMSO/DMF solvent limitation do to enforceability?

High evidentiary leverage

The solvent selection is explicit:

• “selected from the group consisting of DMSO and DMF.”

That is a hard claim boundary for formulation infringement arguments:

• Formulations using neither DMSO nor DMF fall outside the literal solvent limitation.
• Formulations using DMSO and/or DMF keep the claim in play, even with other co-solvents, unless the claims implicitly require solvent identity as the only polar aprotic solvent (the claim text says “selected from the group consisting of,” which typically reads as solvent being limited to DMSO/DMF in that element).

Potential competitor “design-around” direction

The solvent element is the primary “choke point”:

• A competitor can attempt to avoid by using alternative polar aprotic solvents (non-DMSO/DMF).
• If a competitor uses DMSO/DMF, they must clear additional functional and stability claim limitations to reduce risk.

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What are the main functional limitations and how do they change claim posture?

Irradiation stability (claims 2, 12, 31)

• “stable after irradiation” adds a performance standard that is typically fact-heavy.
• It can be difficult to invalidate by composition-only prior art; enforcement often hinges on whether the accused formulation stays within stability criteria post-irradiation.

Water exclusion (claims 3, and dependent 23–32 ecosystem)

• “does not contain components containing added water”
• This limits formulations that include excipients that include added water.
• It can drive disputes around trace water, formulation processing, excipient sourcing, and whether “added water” exists in any component.

Antimicrobial activity without conventional agents (claim 4 and dependents)

• “exhibits bacteriostatic, bactericidal or sporicidal activity without the use of a conventional bacteriostatic, bactericidal or sporicidal agent”
• Plus: peptide must be LHRH-related.

This is the most specialized limitation and the most likely to be litigated:

• It requires (1) an LHRH-related peptide and (2) demonstrated antimicrobial behavior with no conventional antimicrobial added.
• That creates strong room for competitors to argue either lack of antimicrobial effect or presence/requirement of conventional antimicrobial systems.

Anti-gellant effect (claims 11, 21)

• “polar aprotic solvent provides an anti-gellant effect”
• This ties solvent choice to formulation behavior (gelling).
• It may be test-driven and dependent on conditions (concentration, temperature, device architecture).

Thermal stability and storage (claims 7–9, 16–18, 26–28, 35–37)

• These are “bright line” durations and temperatures.
• They often require stability program data to prove or disprove performance.

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What is the effective claim set you provided (mapping scope by category)?

A. Composition-defined claims

• 1: Stable non-aqueous formulation of peptide + polar aprotic solvent = DMSO or DMF
• 2: claim 1 + irradiation stability
• 3: claim 1 + no added-water components
• 4: claim 1 + antimicrobial activity without conventional agents + peptide is LHRH-related

B. Strengthening dependents (additive narrowing)

• Peptide loading: 10% (w/w) and 30% (w/w)
  • 5–6, 14–15, 23–25, 33–34
• Thermal stability:
  • 80° C., 2 months: 7, 16, 26, 35
  • 37° C., 3 months: 8, 17, 27, 36
  • 37° C., 1 year: 9, 18, 28, 37
• Device adaptation:
  • Implantable: 10, 19, 28, 38
• Anti-gellant:
  • 11, 21 (under your claim text, only tied to claim 1 and claim 2 branches)
• LHRH-related:
  • 13, 22, 32 (and claim 4 itself requires LHRH-related)
• Irradiation stability appears again:
  • 12, 31 (as you list it)

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Where does this sit in the U.S. patent landscape for peptide formulations?

Landscape logic (composition-first vs performance-first)

For peptide drug product patents in the U.S., enforcement usually tracks one of two claim styles: 1) Composition-first: stable solvent system, excipients, concentration ranges. 2) Performance-first: stability, device compatibility, antimicrobial behavior, irradiation stability.

Your claim set is a hybrid:

• The solvent element (DMSO/DMF) provides composition-first specificity.
• The remaining limitations are performance-first (stability after irradiation, thermal stability windows, antimicrobial behavior without conventional agents, anti-gellant effect).

Enforcement risk split

• Competitors using DMSO/DMF for peptide solubilization face a tighter composition match.
• Competitors using other solvents face a strong literal avoidance path against claims 1–4, unless doctrine of equivalents arguments are asserted (those are fact-dependent and cannot be evaluated from the claim text alone).

Practical inference for landscape positioning

Within a formulation landscape, this patent likely competes with:

• Prior art on peptide solubility in polar aprotic solvents (DMSO/DMF use is widely explored historically).
• Prior art on non-aqueous peptide formulations for long-term stability.
• Prior art on irradiation sterilization compatibility (depending on packaging and device).
• Prior art on antimicrobial strategies for sterile products (with and without conventional preservatives).
• Prior art on implantable peptide delivery vehicles that need non-gelling properties.

Your provided claims indicate that the differentiator is not merely “use DMSO/DMF,” but achieving specific stability/functional outcomes in those systems.

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What is the claim strength profile (based on the text you provided)?

Highest literal alignment risk

• Any peptide formulation using DMSO or DMF as the polar aprotic solvent and meeting one or more of:
  • irradiation stability
  • no added-water excipient components
  • specified thermal stability windows
  • implantable device adaptation
  • anti-gellant effect (for claims 11/21)
  • LHRH-related antimicrobial performance

Highest burden of proof for an asserting party

• Claims that include experimental performance:
  • “stable after irradiation”
  • “stable at 37° C. for at least one year”
  • “bacteriostatic/bactericidal/sporicidal activity without conventional agent”

These require test method alignment. That shifts disputes toward stability data interpretation and test protocols.

Highest design-around feasibility

• Solvent swap away from DMSO/DMF.
• If a competitor uses alternative polar aprotic solvents, literal infringement on the solvent element is likely reduced substantially.

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Key takeaways on enforceable scope

• The dominant compositional restriction is polar aprotic solvent = DMSO and/or DMF.
• The claim set then narrows based on stability metrics (80° C./2 months; 37° C./3 months; 37° C./1 year) and processing constraints (irradiation stability; no added-water components).
• The most specialized enforcement hook is claim 4: an LHRH-related peptide with antimicrobial activity without conventional antimicrobial agent, plus solvent backbone.
• Quantitative peptide loading is explicitly claimed at 10% and 30% (w/w), tightening product formulation boundaries.

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Key Takeaways

1) Patent scope centers on a non-aqueous peptide formulation with polar aprotic solvent restricted to DMSO/DMF.
2) Dependent claim narrowing is driven by stability after irradiation, water exclusion, thermal stability timelines, and device adaptation.
3) Claim 4 creates a narrow but high-value lane: LHRH-related peptides showing antimicrobial activity without conventional antimicrobial agents.
4) The best practical design-around lever in this claim text is a solvent change away from DMSO/DMF.

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FAQs

1) Does the patent claim all peptide drugs, or only LHRH-related peptides?

Claims 1–3 cover peptide formulations broadly (“at least one peptide compound”). Claim 4 (and its LHRH-related dependents in your list) narrows antimicrobial performance to LHRH-related compounds.

2) What solvent options are explicitly allowed?

The polar aprotic solvent element is limited to DMSO and DMF (“selected from the group consisting of DMSO and DMF”).

3) What stability benchmarks are claimed?

The dependents specify stability at:

• 80° C. for at least 2 months
• 37° C. for at least 3 months
• 37° C. for at least one year

4) Does the claim require irradiation to be used?

The formulation must be stable after irradiation in the relevant claims, but the claims define the formulation property rather than requiring a particular method step in the text you provided.

5) Is antimicrobial activity required for all claims?

No. Antimicrobial activity without conventional agents is part of claim 4 (and the peptide there must be LHRH-related). Claims 1–3 do not impose that antimicrobial requirement as written in your excerpt.

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References

[1] U.S. Patent 6,124,261 (claims as provided in the prompt).

Drugs Protected by US Patent 6,124,261

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate

International Family Members for US Patent 6,124,261

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Argentina	007714
Austria	224199
Austria	263570
Australia	3587997