Analysis of the Scope, Claims, and Patent Landscape of U.S. Patent 4,358,449
Introduction
U.S. Patent 4,358,449, granted on November 9, 1982, to Sterling Drug Inc., covers a class of chemical compounds with potential pharmaceutical applications. Its scope and claims have significantly influenced subsequent drug development, patenting strategies, and legal jurisprudence within medicinal chemistry. This detailed analysis examines the patent’s scope, specific claims, and the broader patent landscape to inform stakeholders about its strategic importance.
Background and Patent Overview
Patent Number: 4,358,449
Grant Date: November 9, 1982
Assignee: Sterling Drug Inc. (now part of Sanofi)
Title: "2-Substituted-4-oxo-3-phenylbutanoyl compounds"
Subject Matter: The patent generally claims a set of chemical compounds, particularly derivatives of 2-substituted-4-oxo-3-phenylbutanoyl compounds, along with methods for their preparation and potential therapeutic utilities.
The patent is rooted in medicinal chemistry, specifically targeting anti-inflammatory and analgesic applications, commonly associated with non-steroidal anti-inflammatory drugs (NSAIDs) or related compounds.
Scope of the Patent
Chemical Scope
The patent’s scope encompasses a broad class of 2-substituted-4-oxo-3-phenylbutanoyl derivatives. The claims specify substituents at various positions, encompassing:
- Aromatic groups: Phenyl rings and their derivatives.
- Substituents on the phenyl ring: Electron-withdrawing or donating groups such as halogens, alkyl, alkoxy, etc.
- Substituents at the 2-position: Diverse groups, including alkyl, aryl, and heteroaryl moieties.
- Variability in the acyl chain: Modifications in the carbon chain to optimize pharmacokinetics and bioavailability.
This structural diversity underpins a wide chemical space, allowing for numerous compounds to fall under the patent's protection.
Methodological Scope
The patent claims extend to:
- The processes for preparing these compounds, including synthetic routes.
- Pharmaceutical compositions containing these compounds.
- Therapeutic methods applying these compounds for anti-inflammatory or analgesic effects.
Limitations and Exclusions
While broad, the patent explicitly limits certain substituents and configurations, which serve as boundaries to prevent the patent from encompassing functionally and structurally unrelated compounds.
Claim Analysis
Claim 1 – Independent Claim
The primary claim (Claim 1) outlines a general formula for the compounds, capturing the core structural features:
A compound of the formula:
wherein R1 is selected from the group consisting of hydrogen, halogen, alkyl, alkoxy, and other substituents; R2 is an alkyl or aryl group; and A is an aromatic or heteroaromatic group.
This claim covers any compound fitting these core structural parameters, provided it is not explicitly excluded by specific subclaims.
Dependent Claims
Dependent claims narrow down Claim 1 by specifying particular substituents, such as:
- Specific halogen substitutions (e.g., chloro, fluoro).
- Particular alkyl chain lengths or aromatic substitutions.
- Specific synthetic methods for generating these compounds.
- Formulation claims for pharmaceutical compositions.
Scope of Claims
The comprehensive coverage ensures protection over a broad chemical spectrum, enabling monopoly over derivatives with similar core structures, provided they meet the functional and substitutive limitations established.
Claims regarding Utility
The claims extend protection beyond chemical structures to include methods of use, notably their therapeutic application as anti-inflammatory agents, indicating a dual claim to both composition and method.
Patent Landscape and Strategic Context
Evolution of Medicinal Chemistry
The patent landscape around 1980s NSAID research was vibrant. U.S. Patent 4,358,449 sits amidst a plethora of patents targeting heteroaryl derivatives, acylaryl structures, and other related anti-inflammatory compounds.
Patent Family and Related Patents
Sterling Drug’s patent family around this technology includes:
- Related patents improving synthesis techniques.
- Similar patents claiming specific substituents or formulations.
- Continuations and divisionals aimed at extending patent protection.
Legal and Commercial Significance
This patent historically provided a robust barrier to generic competitors, especially when the compounds approached commercialization. Its broad claims likely influenced patent strategies in subsequent drug discovery programs, prompting filings for related compounds and formulations.
Inference for Future Innovation
Given the prioritization date in 1980s, the patent’s expiration in 2002 marks a pivotal point when generic development could proceed freely. Post-expiration, companies can now explore derivatives within the chemical space initially claimed, provided they do not infringe on other active patents.
Legal Status and Enforcement
The patent was maintained through its term and eventually expired, opening the field for generic manufacturers and biosimilars. Its enforceability in litigations focused on compounds within its claim scope reinforced its strength during active patent life.
Conclusion
U.S. Patent 4,358,449 captures a significant chemical space of 2-substituted-4-oxo-3-phenylbutanoyl derivatives, with broad claims covering core structures and their therapeutic uses. It played a strategic role in anti-inflammatory drug development during the 1980s and 1990s, shaping the patent landscape in this therapeutic class. Its expiration has subsequently facilitated broader research and development in related compounds.
Key Takeaways
- The patent’s broad claims encompass a wide array of derivatives within the chemical space of phenylbutanoyl compounds, providing substantial protection during its active life.
- Its claim structure includes both composition and method-of-use claims, enhancing its strategic value.
- The patent landscape around this compound class was dense, with related patents reinforcing its influence.
- Post-expiration, the patented chemical space is open for innovation, contingent on respecting other existing patents.
- Stakeholders should analyze active patents in related classes to develop non-infringing derivatives for medicinal use.
FAQs
-
What was the primary therapeutic application claimed under U.S. Patent 4,358,449?
The patent primarily targeted anti-inflammatory and analgesic uses, consistent with NSAID-like compounds.
-
How broad are the chemical claims in this patent?
Very broad—covering a wide class of 2-substituted-4-oxo-3-phenylbutanoyl derivatives, with various substituents at multiple positions.
-
Did the patent claim any specific synthesis methods?
Yes. The patent included claims on particular synthetic routes for preparing these derivatives, facilitating process protection as well.
-
What impact did the patent have on subsequent drug development?
It served as a foundational patent influencing the development of derivatives and related compounds, shaping research strategies within the therapeutic class.
-
Is the patent still enforceable?
No. It expired in 2002, opening its chemical space for generic and research applications, though other patents may still provide protection.
References
[1] U.S. Patent 4,358,449. Sterling Drug Inc. (1982).
[2] Patent landscape and medicinal chemistry literature contextualizing NSAID patenting during the 1980s.
[3] Legal and commercial analyses of patent expiration impacts on drug markets.
