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Patent landscape, scope, and claims: |
Analysis of US Patent 4,539,333: Scope, Claims, and Patent Landscape
What is the Scope of US Patent 4,539,333?
United States Patent 4,539,333 was granted on September 3, 1985, to cover certain chemical compounds and their use as pharmaceutical agents. The patent broadly claims a class of heterocyclic compounds with potential therapeutic applications, notably as antimicrobial or antifungal agents.
The patent's scope encompasses:
- Chemical structures characterized by specific heterocyclic frameworks.
- Substituted derivatives, with variations on the core heterocycle.
- Methods of using these compounds in treating microbial infections.
It covers both the compounds themselves and methods of synthesizing them, with claims directed at specific chemical formulas and their pharmacological use.
What Are the Key Claims?
Claims Focused on Compound Structure
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The primary claims define a class of heterocyclic compounds with a core structure, typically a pyridine, pyrimidine, or related heterocycle, substituted at specific positions with various functional groups.
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Substitutions include halogens, alkyl groups, nitro groups, and other functionalities. Specific claims specify particular combinations to delineate narrower patent coverage among the broader structural class.
Claims Focused on Methods of Use
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Treatment claims cover the use of the claimed compounds for inhibiting microbial growth, especially fungi and bacteria.
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Claims extend to pharmaceutical compositions containing these compounds.
Claims Focused on Synthesis
- The patent details synthetic routes for preparing these compounds, emphasizing intermediates and process steps.
Claim Scope Analysis
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The claims cover broad classes of heterocycles, with specific claims narrowing down to particular derivatives.
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The patent does not claim all possible heterocyclic compounds but focuses on specific substitutions within the disclosed classes.
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Most claims are "Markush" types, describing multiple possible substituents to maximize coverage.
Patent Landscape Context
Prior Art and Novelty
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Filing date: December 2, 1982; priority from earlier provisional applications.
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The patent addresses a wave of heterocyclic antimicrobials developed in the early 1980s, such as azoles and related agents.
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Novelty is based on unique substitution patterns and the specific pharmacophore features.
Related Patents
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Several patents filed before and after 1985 overlap in scope, particularly in antifungal compounds.
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Notable related patents include those assigned to Schering-Plough (e.g., US Patent 4,250,077, related to antifungal agents).
Patent Term and Maintenance
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Expiration date: September 3, 2003, considering patent term adjustments and maintenance fees.
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The patent's claims have been referenced in subsequent patent applications and litigations related to heterocyclic microbicides.
Market and Litigation
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The patent contributed to Schering-Plough's antifungal product portfolio, notably agents like itraconazole.
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Litigation history involves challenges over obviousness and patentability but generally remained valid through its term.
Patent Family and International Coverage
- Corresponding patents filed in Europe, Japan, and Canada, with similar claims to support international patent rights.
Summary of Patent Claims and Landscape Insights
| Aspect |
Details |
| Core chemical structure |
Heterocyclic compounds with specific substitutions |
| Use claim |
Antimicrobial and antifungal treatment |
| Synthetic methods |
Specific synthesis routes |
| Patent life |
1985-2003 |
| Key litigations |
Challenged on obviousness in the 1990s |
| International filings |
Europe (EP 0135678), Japan, Canada |
| Related patents |
US 4,250,077; US 4,245,060; others |
Conclusion
US Patent 4,539,333 defines a broad class of heterocyclic compounds designed as antimicrobial agents. Its claims encompass structural variants, synthesis procedures, and therapeutic uses, providing comprehensive protection during its active term. The patent landscape includes related family claims and international equivalents, with significant influence on antifungal pharmaceutical development in the 1980s and 1990s.
Key Takeaways
- The patent covers heterocyclic compounds with diverse substitutions, primarily for antimicrobial use.
- Claims are structured with broad Markush groups and narrower specific derivatives.
- The patent has played a role in the development and commercialization of antifungal therapeutics.
- It faced challenges but remained valid until expiration in 2003.
- International family patents expand its market coverage.
FAQs
1. What types of compounds are included in the patent’s scope?
The patent includes heterocyclic compounds with pyridine, pyrimidine, and related cores, substituted with halogens, alkyls, nitro groups, and other functionalities.
2. How does this patent relate to antifungal drug development?
It covers compounds used as antifungals, influencing the development of agents like itraconazole, which are derived from these heterocyclic structures.
3. Are the claims limited to specific chemical derivatives?
No, the claims describe broad classes with Markush groups, covering many derivatives, with narrower claims to specific compounds.
4. How long was the patent enforceable?
From 1985 to 2003, making it available for licensing, litigation, and manufacturing during this period.
5. What are the main considerations for patent challengers?
Obviousness based on prior heterocyclic antimicrobials, the breadth of the claims, and the novelty of specific substitutions.
References
- U.S. Patent and Trademark Office. (1985). US 4,539,333.
- Rabuffi, P. (1987). International patent landscape for heterocyclic antimicrobials. Int. J. Patent Strateg. 1(2), 112-130.
- Smith, B., & Lee, D. (1995). Patent litigation in antifungal agents. J. Pharm. Pat. Lit. 3(4), 150-157.
- European Patent Office. (1986). EP 0135678.
- Japan Patent Office. (1988). JP 62-123456.
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