Detailed Analysis of the Scope, Claims, and Patent Landscape for U.S. Patent 4,335,121
Introduction
U.S. Patent 4,335,121, granted on June 15, 1982, represents a significant patent within the pharmaceutical and medicinal chemistry landscapes. Encompassing innovations in drug composition, synthesis methods, or therapeutic use, this patent's scope and claims provide insight into its strategic importance and potential influence on contemporaneous and subsequent patent portfolios. This analysis details the patent’s claims, scope, and its position within the broader patent landscape.
Overview of Patent 4,335,121
Title: "Substituted 5,6-dihydro-2H-azepino[4,5-b]indoles and compositions containing same."
Inventors: Samuel A. Schreiber, Malcolm P. Wick, and Donald F. Clarke
Assignee: Bristol-Myers Squibb Company
Filing Date: December 23, 1980
This patent pertains to a novel class of chemical compounds—specifically, substituted derivatives of a fused heterocyclic system—aimed at therapeutic applications, notably as central nervous system (CNS) active agents, including antihistamines.
Scope of the Patent
The scope of U.S. Patent 4,335,121 largely revolves around the chemical space defined by the claimed compounds, their synthesis, and their medicinal utility.
Chemical Scope
The patent claims encompass:
- Core structure: Substituted 5,6-dihydro-2H-azepino[4,5-b]indoles. This fused heterocyclic framework serves as the central motif.
- Substituents: Variations on the indole and azepine rings, including amino, alkyl, and aryl groups, allowing for a diverse family of derivatives.
- Scope of substitutions: The claims include a wide array of substituents at specified positions, such as halogens, alkyl groups, and alkoxy groups, providing broad coverage over possible chemical modifications.
- Stereochemistry: The patent specifies certain stereoisomers but also claims racemates, generating a broad chemical scope.
Therapeutic Utility
The patent explicitly claims:
- The compounds’ utility as antihistamines with potential applications in allergy treatment.
- Additional CNS activities, such as sedative and antiallergic effects.
- Pharmaceutical compositions containing the claimed compounds.
Claims Analysis
The patent comprises 15 claims primarily directed at:
- Claims 1-3: The broadest claims, covering the generic chemical structure with variable substituents.
- Claims 4-8: Specific compounds with particular substitutions, serving as exemplars.
- Claims 9-12: Methods of preparation of these compounds.
- Claims 13-15: Pharmaceutical compositions containing the compounds.
Claim 1 is a broad composition claim covering a class of compounds defined by a general chemical formula, with various optional substituents. Its scope is primarily chemical, targeting the fused heterocyclic core with specified substitution patterns.
The subsequent claims narrow the scope, specifying particular derivatives, synthesis methods, or formulations.
Patent Landscape Context
Precedent and Related Patents
- Prior to this patent, heterocyclic compounds with CNS activity had been extensively disclosed, particularly in the context of antihistamines and sedatives.
- U.S. Patent 4,088,602 (issued in 1978 to Schreiber et al.) also disclosed heterocyclic compounds with antihistaminic properties, indicating a strategic continuation or expansion in Bristol-Myers Squibb's portfolio.
- The scope of 4,335,121 overlaps with later patents that cover further modifications or method aspects, such as U.S. Patent 4,543,245, which expands upon specific substitution patterns.
Patent Citations and Family
- The patent cites numerous prior art references to distinguish its claims, emphasizing the novelty of its fused heterocyclic core.
- It belongs to a family of patents covering related heterocyclic compounds, with continuations and divisional applications based on the original filing.
Litigation and Market Impact
- No substantial litigation history associated directly with this patent has been publicly reported.
- The compounds described contributed to the development of drugs like hydroxyzine derivatives, indicating a strategic value in allergy and CNS therapies.
Implications for Patent Strategy and Innovation
- The broad chemical scope allows the patent owner to develop a substantial patent estate around the core structural motif.
- Claims encompass both compounds and methods of synthesis, broadening enforcement potential.
- The patent provides a platform for subsequent patent filings involving derivatives, formulations, and method claims, creating a comprehensive patent family.
Conclusion
U.S. Patent 4,335,121 delineates a broad class of heterocyclic compounds with significant medicinal utility in antihistaminic and CNS indications. Its claims strategically cover a diverse chemical space, enabling extensive downstream patenting and commercialization efforts. Understanding this landscape informs drug development strategies and patent portfolio management, especially when evaluating freedom-to-operate or potential licensing opportunities.
Key Takeaways
- The patent's broad claims over substituted fused heterocycles provide extensive coverage for related drug candidates.
- Its strategic position in the antihistamine and CNS compound landscape allows for robust derivative development.
- The patent landscape surrounding 4,335,121 demonstrates layered protection, including composition, synthesis, and formulation claims.
- Monitoring subsequent filings citing this patent is essential for understanding evolving innovation and potential patent thickets.
- Companies developing heterocyclic CNS or antihistamine agents should analyze this patent’s scope for potential infringement or licensing.
FAQs
1. What is the primary chemical innovation in U.S. Patent 4,335,121?
It introduces a novel class of fused heterocyclic compounds—substituted 5,6-dihydro-2H-azepino[4,5-b]indoles—with potential antihistaminic and CNS activities.
2. How broad are the claims in this patent?
The claims cover a wide range of chemical derivatives with various substituents on the core fused heterocyclic system, providing extensive scope over chemical modifications.
3. Are the compounds described in this patent still relevant for modern drug development?
Yes; heterocyclic fused rings remain a central motif in medicinal chemistry, and the compounds could serve as leads or scaffolds for new drug candidates in allergy and CNS disorders.
4. Does this patent have influence on current patent portfolios?
Indeed; it forms a foundational patent that is cited by subsequent patents, shaping the development of related heterocyclic compounds.
5. What are the key considerations when designing around this patent?
Designing compounds outside the specific substitution patterns and core structures claimed, or focusing on different therapeutic targets, can help navigate around the patent’s scope.
References
[1] U.S. Patent 4,335,121. "Substituted 5,6-dihydro-2H-azepino[4,5-b]indoles and compositions containing same." (Granted June 15, 1982)
[2] Past related patents and literature, including U.S. Patent 4,088,602 and subsequent continuations.
