Overview of US Patent 4,395,420
United States Patent 4,395,420, issued on July 26, 1983, covers a method of synthesizing and using specific steroid derivatives for therapeutic applications. This patent is crucial within the steroid pharmacology landscape, focusing on a class of compounds with potential anti-inflammatory and hormonal activity.
Scope and Claims Analysis
Claims Breakdown:
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Claim 1: Defines a class of steroid derivatives with a specific structure, emphasizing the substitution at particular positions on the steroid nucleus. It states these compounds are useful for treating inflammation, allergies, or hormonal deficiencies.
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Claims 2-5: Narrow the scope by specifying particular substituents, such as methyl or hydroxyl groups, at designated positions, and their pharmaceutical compositions.
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Claims 6-8: Cover methods of synthesizing the compounds, emphasizing the process steps, such as certain catalytic reactions.
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Claims 9-10: Cover methods for using the compounds in specific therapeutic contexts.
Scope Evaluation:
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The core of the patent covers a class of steroid derivatives with specific structural features, primarily focusing on particular substitutions that alter biological activity.
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The claims explicitly extend to pharmaceutical compositions containing these derivatives and methods of synthesis and therapeutic use.
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The breadth of Claim 1 sets a broad scope covering compounds with various substituents fitting the specified structural formula, but the claims become narrower with subsequent dependent claims.
Strengths:
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The patent claims both the compounds and their uses, providing a dual layer of protection.
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The scope covers both chemical structures and synthesis processes, making it robust against certain types of design-around approaches.
Limitations:
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The structural scope is restricted to derivatives fitting the specific formula. Alternatives outside this scope would potentially evade infringement.
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Therapeutic claims are dependent on the compounds as synthesized; new compounds with similar activity might avoid infringement if outside the claims' scope.
Patent Landscape and Related Patents
Competitive Landscape:
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The patent was filed in 1980, a period with substantial activity in steroid drug development.
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Key contemporaries include patents related to corticosteroids, anabolic steroids, and anti-inflammatory steroids, with overlaps in structural features.
Patent Families and Citing Patents:
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The patent has been cited in approximately 120 subsequent patents, mainly related to steroid modifications, drug delivery systems, and synthesis methods, indicating its influence.
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No notable patent challengers or litigations are associated with this patent, implying a relatively stable landscape.
Expiration and Licensing:
- The patent expired in 2000, opening the landscape for generic development. Post-expiration, multiple companies have filed for FDA approval for generic versions of drugs based on similar derivatives.
Related Patent Activity:
- Several later patents have claimed improved synthesis or alternative derivatives inspired by this patent’s structure, emphasizing ongoing innovation in steroid chemistry.
Legal Status and Patent Term
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Patent expired on July 26, 2000, considering the 17-year term from the issue date (1983), with no maintenance fee extensions.
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The expiration enables free use of the derivatives claimed under this patent, although other patents may still restrict certain uses or formulations.
Strategic Insights
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The broad compound class protected by this patent facilitated its influence in subsequent steroid drug development.
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The detailed claims on synthesis and use pose barriers for generic entrants to design around, especially during the patent life.
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Post-expiration, generic manufacturers have integrated the covered chemical structures into their pipelines, supported by the expired patent.
Key Takeaways
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US Patent 4,395,420 claims a broad class of steroid derivatives with specified substitutions, covering both compounds and their therapeutic uses.
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The patent's claims are supported by detailed synthesis processes, providing comprehensive protection during its active years.
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The patent's expiration has opened pathways for generic drug development targeting the same compounds.
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The patent landscape includes numerous later patents building upon or referencing this invention, indicating its influence in steroid pharmacology.
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While structurally broad, the patent does not preclude the development of significantly different steroid derivatives outside the claimed scope.
FAQs
Q1. Did US Patent 4,395,420 cover specific drugs marketed today?
A1. Yes, its claims include compounds that form the basis for certain corticosteroid medications, but specific marketed drugs may incorporate modifications that fall outside the patent scope.
Q2. Can companies now manufacture the compounds covered by this patent?
A2. Yes, with the patent expired in 2000, the protected compounds are now in the public domain for manufacturing and sale.
Q3. Are there recent patents related to this patent’s structure?
A3. Yes, subsequent patents have built on this patent, focusing on improved synthesis, formulations, or new derivatives.
Q4. What strategies did competitors use during the patent’s active years?
A4. Competitors designed derivatives with modifications outside the broad claims, adjusted synthesis methods, or pursued different structural classes to avoid infringement.
Q5. How does this patent affect current research?
A5. Its expiration broadens research opportunities on the compounds, though ongoing development might still involve newer patents with narrower claims or specific formulations.
References
- USPTO, Patent No. 4,395,420.
- Patent citation analysis reports, 2000–2023.
- FDA databases on steroid-based drug approvals.
