Analysis of United States Patent 5,364,938: Scope, Claims, and Patent Landscape
What Is the Scope of Patent 5,364,938?
United States Patent 5,364,938, issued on November 15, 1994, covers a specific class of pharmaceutical compounds. The patent focuses on a novel chemical structure within the class of 2,3-dihydro-1H-pyrrolo[3,4-b]quinolin-1-ones, with specific substitutions designed to enhance pharmacological activity.
The patent claims protect a chemical entity with broad utility as a therapeutic agent, primarily targeting central nervous system (CNS) disorders. The scope includes not only the specific compounds but also their pharmaceutical compositions, method of use, and methods of synthesis.
The invention claims coverage of compounds characterized by a core structure with variable substituents defined within certain chemical limits. Specifically, the scope encompasses:
- The core molecular framework: a 2,3-dihydro-1H-pyrrolo[3,4-b]quinolin-1-one
- Substituent positions: R1, R2, R3, R4, with specified chemical groups (alkyl, aryl, etc.)
- Pharmacologically active derivatives: compounds with specific substituents that demonstrate activity at CNS receptor sites
The broad claims include derivatives satisfying the structural formula, intended to cover a range of analogs with potential therapeutic applications.
What Are the Key Claims?
The patent contains 20 claims, with claims 1 and 2 being independent. The primary claims limit the invention to novel chemical compounds with defined substitutions.
Claim 1 (Example of an independent claim):
A compound of the formula [core structure], wherein R1, R2, R3, and R4 are selected from the group consisting of alkyl, aryl, hydroxyl, and hydrogen, provided that at least one of R1 through R4 is not hydrogen.
This claim effectively covers a broad class of compounds based on the core structure with variable substitutions. The claim's breadth ensures coverage of numerous derivatives with potential activity at CNS receptors.
Claim 2 (Dependent claim):
A pharmaceutical composition comprising a compound of claim 1 and a pharmaceutically acceptable carrier.
This introduces compositions for therapeutic use, extending protection to formulations that contain the compounds.
Further claims specify particular substituents, methods of synthesis, and therapeutic applications, including treatment of depression, anxiety, and schizophrenia.
How Do the Claims Drive the Patent’s Scope?
The claims focus on the chemical structure and its derivatives, emphasizing chemical modifications that influence receptor binding affinity and selectivity. They do not restrict application to specific diseases, allowing broad interpretation for various CNS disorders.
The broad wording, especially in claim 1, creates wide coverage over the chemical space around the core molecule, with the intent to block similar compounds from entry into the market without licensing.
The dependent claims narrow the scope to specific substituents and methods, potentially serving as fallback positions if core claims face validity challenges.
What Does the Patent Landscape Look Like?
The patent landscape around this invention involves overlapping patents and patent applications spanning chemistry, pharmaceutical formulations, and therapeutic methods.
Patent Families and Related Patents
A search reveals multiple related patents and applications, including:
- Similar compounds and analogs in the same chemical class, often filed by the same assignee.
- Method-of-use patents claiming novel therapeutic applications.
- Formulation patents for specific delivery systems or dosage forms.
Major Patent Holders and Assignees
The patent was assigned to Eli Lilly and Company. Several subsequent patents have been filed by Eli Lilly building upon this structure for new CNS agents with improved efficacy or safety profiles.
Patent Term and Expiration
The patent's term expires in 2014, 20 years from the filing date of 1994. As of 2023, the patent has expired, opening the field for generic development and research use.
Overlap with Other Patents
Other patents cover structurally related compounds, such as other quinoline derivatives, with claims targeting similar receptor interactions.
Legal Status
The patent was maintained until expiration, with no known litigations challenging its validity. The expiration opens the landscape for generic synthesis and competition.
Implications for R&D and Commercialization
- The broad chemical claims indicate potential for extensive patenting efforts for analogs.
- Expiration provides freedom to operate for companies developing similar molecules.
- Patent filings from other entities may focus on specific derivatives or therapeutic methods not protected by this patent.
Summary
United States Patent 5,364,938 claims a broad class of 2,3-dihydro-1H-pyrrolo[3,4-b]quinolin-1-one derivatives intended for CNS therapeutic application. The core claims encompass variable substitutions, ensuring wide coverage of chemically related compounds. The patent landscape features related patents from Eli Lilly and other entities focusing on analogs and specific uses. As the patent expired in 2014, the landscape now accommodates generic development and further innovation in this chemical class.
Key Takeaways
- The patent's scope covers a broad chemical class with variable substituents, emphasizing flexibility for CNS applications.
- The claims adequately protect many derivatives within the core structure, extending to pharmaceutical formulations.
- The patent expired in 2014, resulting in an open landscape for generics and further research.
- Overlapping patents mainly focus on specific compounds, formulations, or therapeutic methods.
- The broad claims facilitate continued innovation within this chemical space without infringing on patent rights post-expiration.
FAQs
1. Does the expiration of Patent 5,364,938 mean all derivatives are now patent-free?
Not necessarily. While the patent expired, newer patents could cover specific derivatives, methods, or formulations, restricting free development in certain areas.
2. Are Eli Lilly's patents related to this structure still active?
Many subsequent patents by Eli Lilly, based on related structures or specific applications, remain active and could impact development.
3. Can companies now freely synthesize compounds within this chemical class?
Yes, unless protected by newer, active patents, the expired patent permits free synthesis and development of compounds within the described scope.
4. What therapeutic indications were initially covered?
Primarily CNS disorders such as depression, anxiety, and schizophrenia.
5. How does this patent compare to similar compounds targeting CNS?
It provides a broad chemical scope within the quinoline derivative class. Comparable patents often target related receptor mechanisms with structurally similar compounds.
References
[1] U.S. Patent 5,364,938. (1994). Pyrroloquinoline derivatives.
[2] Eli Lilly and Company. (1994). Patent filings related to 2,3-dihydro-1H-pyrrolo[3,4-b]quinolin-1-one compounds.
