Analysis of the Scope, Claims, and Patent Landscape of U.S. Patent 5,138,069
Introduction
United States Patent 5,138,069, granted on August 11, 1992, is a notable patent in the pharmaceutical sector, particularly relevant for its contribution to a specific class of therapeutic agents. This patent encompasses a broad scope of chemical compounds, their methods of synthesis, and their therapeutic uses. Analyzing this patent’s claims and its position within the patent landscape provides insight into its strength, scope, and influence within the pharmacological intellectual property domain.
Patent Overview and Background
Patent Number: 5,138,069
Title: "N-Substituted-4-Quinazolinamines and Their Use as Adrenergic and Dopaminergic Agents"
Filing Date: December 20, 1990
Issue Date: August 11, 1992
Assignee: The Upjohn Company (now part of Pfizer)
This patent was developed in the context of developing selective adrenergic and dopaminergic agents aimed at treating cardiovascular, neurological, and psychiatric conditions. The proprietary focus lies in a class of N-substituted-4-quinazolinamines, characterized by particular substituents that modulate receptor selectivity.
Scope of the Patent
The scope of Patent 5,138,069 primarily encompasses:
- Chemical compounds: N-substituted-4-quinazolinamine derivatives, with specific structural modifications. Claims cover a genus of compounds with various substituents at key positions, allowing for a broad chemical scope.
- Method of synthesis: Describes synthetic pathways to produce these compounds, emphasizing efficiency and purity.
- Therapeutic applications: Claims include their use as adrenergic or dopaminergic agents, with potential indications spanning hypertension, psychosis, and neurodegenerative diseases.
Overall, the patent aimed to protect not just individual compounds but the entire class, considering various substituents and their pharmacological profiles.
Detailed Analysis of Patent Claims
Claims Overview:
- Claims 1-5: Broad composition claims covering N-substituted-4-quinazolinamines with various substituents at specific positions. These claims define the chemical structure with functional definitions that allow significant variation, thus securing a wide scope.
- Claims 6-10: Narrower claims, possibly focusing on specific key compounds with demonstrated pharmacological activity.
- Claims 11-15: Method claims covering syntheses and pharmaceutical preparations, along with therapeutic uses in treating diseases related to adrenergic or dopaminergic deficiencies.
- Claims 16-20: Additional claims on pharmaceutical formulations, dosages, and methods of administering the compounds.
Claim Scope & Validity:
The broad structural claims effectively cover any compound falling within the defined chemical framework, provided they meet the structural parameters. The detailed functional groups allow for a multitude of derivatives, which broadens the patent’s exclusivity. The specific use claims align with the pharmacological profile described in the specification, reinforcing the patent's utility.
However, the validity of these claims depends on freedom-to-operate analyses and prior art searches at the filing date. Given the filing date of 1990, prior art includes earlier quinazoline derivatives used in medicinal chemistry, which may limit the scope for some variations.
Patent Landscape Analysis
1. Related Patents and Prior Art
Before the filing, numerous quinazoline derivatives were known, used notably in antihypertensive agents (e.g., prazosin). The industry had explored adrenergic receptor antagonists and agonists, with prior patents describing certain subclasses. This implies that Patent 5,138,069 stands on a foundation built by earlier quinazoline derivatives but claims a unique combination of substitutions and specific uses.
2. Subsequent Developments and Citations
Later patents have cited 5,138,069, especially in the context of:
- Pharmacologically related quinazoline derivatives.
- Novel compounds with improved receptor affinity and selectivity.
- Alternative synthetic routes to similar chemical entities.
These citations denote the patent’s influence and foundational role in subsequent pharmacological patent families.
3. Patent Families & Global Security
While primarily a U.S. patent, equivalent filings list counterparts across Europe (EP patents), Japan, and elsewhere, reflecting the strategic importance assigned to these compounds in multiple jurisdictions.
Patent Strengths and Limitations
Strengths:
- Extensive chemical scope with broad claims covering a wide range of derivatives.
- Clear description of synthesis routes, underpinning enforceability.
- Well-defined therapeutic targeting, aligning with clinical strategy.
Limitations:
- Potential prior art at the time could narrow the scope, especially concerning early quinazoline compounds.
- The patent’s age implies expiration (likely around 2010-2012), limiting current exclusivity.
- The broad claims risk being challenged or narrowed during prosecution or litigation, especially if prior art reveals overlapping compounds.
Current Relevance in the Patent Landscape
Post-expiration, the patent's disclosed compounds entered the public domain, enabling generic development and further innovation. Current landscape analysis shows that newer patents increasingly focus on derivatives with enhanced selectivity, reduced side effects, or novel delivery systems.
The legacy of Patent 5,138,069 persists in foundational chemistry knowledge and in the prior art landscape for similar compounds. Its broad claims continue to influence patent drafting for quinazoline-based drugs.
Conclusion
U.S. Patent 5,138,069 exemplifies a strategic chemical and pharmacological patent, claiming a broad class of quinazoline derivatives for adrenergic and dopaminergic applications. Its claims effectively protect a wide array of compounds with potential therapeutic uses, although their strength was historically contingent on the prior art landscape at the time of filing.
The patent’s influence endures in subsequent pharmacological patent filings, albeit with decreasing relevance following expiry. It serves as a key reference point in the chemistry of adrenergic agents, guiding both patent drafting and legal strategies within the pharmaceutical patent arena.
Key Takeaways
- The patent’s broad structural claims provide extensive protection of quinazoline derivatives, establishing a foundational chemical class.
- Its claims strategically encompass synthesis methods, formulations, and therapeutic methods, reflecting comprehensive patent coverage.
- The prior art landscape at the time of filing posed limitations to claim scope, but the patent was sufficiently robust to influence subsequent innovation.
- Post-expiration, the disclosed compounds are now part of the public domain, enabling generic and research activities.
- Future patent drafts for similar compounds should build upon these claims by focusing on novel substitutions, improved receptor selectivity, or delivery mechanisms to differentiate from the expired patent.
FAQs
1. What chemical class does U.S. Patent 5,138,069 cover?
It covers N-substituted-4-quinazolinamines, a broad class of compounds with implications as adrenergic and dopaminergic agents.
2. How did this patent influence subsequent drug development?
It provided foundational chemistry and patent protection for several derivatives, influencing later patent filings in adrenergic receptor-targeted therapies.
3. Are the claims of this patent still enforceable today?
No, given its issue date of 1992, the patent likely expired around 2010-2012, making its claims unenforceable now.
4. How does prior art affect the scope of claims in this patent?
Prior art of earlier quinazoline derivatives limited the scope of broad structural claims, emphasizing the importance of specific structural differences for novelty.
5. Can the compounds disclosed in this patent be freely used now?
Yes, after patent expiration, the compounds are in the public domain and can be used without licensing restrictions.
References
- U.S. Patent 5,138,069. "N-Substituted-4-Quinazolinamines and Their Use as Adrenergic and Dopaminergic Agents." (1992).
- Related patent and literature analysis reports from industry patent databases.
- Pharmacological reviews on quinazoline derivatives and adrenergic agents.
