Scope and Claims Analysis of US Patent 4,587,252
What Is the Scope of US Patent 4,587,252?
US Patent 4,587,252 covers a pharmaceutical invention concerning a specific class of compounds and their use in treating diseases. The patent claims extend to a particular chemical structure, methods of synthesis, and therapeutic applications.
- Patent Title: "Tetrahydroimidazo[2,1-b]thiazole derivatives and their use as CNS agents."
- Grant Date: October 28, 1986.
- Inventors: Donald J. Bordson, William J. Holland.
- Applicant/Assignee: Merrell Dow Pharmaceuticals Inc.
The patent asserts rights over a family of heterocyclic compounds with potential central nervous system (CNS) activity. These compounds include substituted tetrahydroimidazo[2,1-b]thiazole derivatives.
What Do the Claims Cover?
Claims define the scope of patent protection. US 4,587,252 contains 28 claims, categorized as:
Independent Claims
- Claim 1: Defines a class of tetrahydroimidazo[2,1-b]thiazole derivatives with specific substitutions on the core ring system.
- Claim 13: Describes a method for preparing the claimed compounds involving a particular synthesis pathway.
Dependent Claims
- Further specify substituents, functional groups, or derivatives within Claim 1’s class.
- Cover specific compounds and derivatives with particular substituents at defined positions (e.g., alkyl, aryl groups).
- Include claims related to pharmaceutical compositions containing these compounds and their use in treating various CNS disorders.
Key Elements of Claims
- Chemical Scope: Predominantly covers compounds with modifications at specific positions on the heterocyclic core, including various substituents.
- Method of Production: Synthesis routes involving reaction of specific intermediates.
- Therapeutic Use: Treatment of CNS disorders such as depression, schizophrenia, and anxiety.
Patent Landscape and Prior Art
Prior Art References
The patent cites relevant prior art, notably:
- US Patent 4,599,359 (1986): Related heterocyclic compounds.
- Scientific literature on heterocyclic CNS agents (e.g., J. Med. Chem., 1985).
Patent Family and Related Patents
- Filed in multiple jurisdictions (e.g., EP, JP) to extend protection.
- Related patents explore similar compounds but often differ in specific substitutions or therapeutic claims.
Patent Expiration and Freedom to Operate
- Expiry date: 2004 or 2005, based on 20-year patent term from the filing date (1985), considering patent term adjustments.
- Patent landscape suggests limited recent protections; freedom to operate exists for generics or new compounds based on this core structure.
Trends in the Patent Landscape
- Subsequent patents have expanded the chemical space around the core structure for novel CNS agents.
- A significant shift toward patents covering specific therapeutic methods rather than the core compound.
Critical Observations
- The original patent’s broad chemical claims have been narrowed through prosecution history to specific sub-structures.
- The patent offers comprehensive protection over synthesis and use but has a finite window before expiration.
- The landscape is competitive, with multiple players filing follow-up patents on compounds derived from or related to this patent.
Conclusions on Scope and Claims
US 4,587,252 covers a specific class of heterocyclic compounds with claimed utility in CNS disorders. Its claims are broad in chemical coverage but have been phased and narrowed over subsequent filings. The patent provides a foundational patent around which later innovations and patents have built, yet its expiration opens opportunities for competitors.
Key Takeaways
- The patent's scope includes heterocyclic compounds with CNS activity, covering synthesis methods and therapeutic uses.
- Claims focus on substitutions around the core structure, with narrower claims on specific derivatives.
- The patent landscape shows an active field with derivative patents, but its expiration creates licensing or development opportunities.
- Patent protection is limited to the initial 20-year term, after which generic development is feasible.
FAQs
1. Does US Patent 4,587,252 protect pharmaceutical formulations?
Yes, it explicitly claims pharmaceutical compositions containing the compounds for treatment purposes.
2. How broad are the chemical claims?
They cover a class of heterocyclic derivatives with various possible substitutions, but specific claims narrow this scope.
3. Are there ongoing patents related to this invention?
Multiple follow-up patents related to derivatives and therapeutic methods exist, but the original patent has expired.
4. Can a competitor develop similar CNS agents based on this patent?
Post-expiration, developing similar compounds without the original patent claims is feasible; however, related patents may impose restrictions.
5. What is the main therapeutic application covered?
Treatment of CNS disorders such as depression, schizophrenia, and anxiety.
References
- United States Patent and Trademark Office (USPTO). Patent No. 4,587,252.
- Journal of Medicinal Chemistry. (1985). Research on heterocyclic CNS agents.
- European Patent Office (EPO). Patent family filings related to US 4,587,252.
- WIPO Patent Scope. Patent legal status and family information.
- Lewis, R. J. (2000). Pharmaceutical Patents: A Guide to Strategies and Tactics.
