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Patent landscape, scope, and claims: |
Scope and Claims of U.S. Patent 3,910,924
Patent 3,910,924 covers a class of pharmaceutical compounds classified as quinazoline derivatives, specifically targeting the treatment of certain diseases such as hypertension. The patent's claims extend to the chemical structures, their synthesis methods, and their therapeutic applications.
Core Claims Breakdown
Claim 1:
Defines a quinazoline compound with a specific substitution pattern, characterized by the general formula:
[ \text{Quinazoline core} \quad \text{with substitutions at positions 2, 4, and 7} ]
Specifically, it claims compounds where:
- The quinazoline nucleus is substituted with alkyl, alkoxy, or amino groups.
- The substituents at positions 2, 4, and 7 follow particular definitions, often including benzyl, phenyl, or heteroaryl groups.
Claims 2-10:
Describe specific embodiments of these compounds, including particular substituents, their stereochemistry, and physicochemical properties.
Claims 11-15:
Cover methods of synthesizing the compounds, involving cyclization and substitution reactions.
Claims 16-20:
Relate to pharmaceutical compositions containing the claimed compounds, including doses, formulations, and administration routes.
Claims 21-25:
Assert therapeutic methods, primarily administering effective doses of these compounds to treat hypertension or other vasorelaxant conditions.
Scope Summary
- Focused on a series of quinazoline derivatives with potential antihypertensive activity.
- Claims extend to specific substitutions on the quinazoline core and preparatory methods.
- Encompasses both the compounds themselves and their pharmaceutical formulations.
- Includes claims for methods of treatment using the compounds.
Patent Landscape for Quinazoline Derivatives (Pre- and Post-1960s)
Historical Context
U.S. patent 3,910,924 was granted in 1975. It represents early exploration into quinazoline derivatives for medical use, following foundational work in heterocyclic chemistry. The landscape includes:
- Early patents (1950s-1960s): Focused on quinazoline synthesis and biological activity.
- Mid-1970s: Introduction of specific compounds with claimed pharmacological activity.
- Subsequent patents (post-1975): Focused on optimizing potency, selectivity, and formulations.
Key Landscape Features
- Breadth of Claims: The patent claims an extensive class of derivatives, common in chemical patenting to cover a broad potential scope.
- Patent Families: This patent links to broader families filed internationally (e.g., in Europe, Japan, Canada) to protect potential markets.
- Citations and Follow-On Patents: Highly cited by subsequent patents relating to kinase inhibitors, antihypertensives, and anticancer agents, often focusing on quinazoline core modifications.
Major Patent Players
- Companies involved include Schering AG (later part of Bayer), which contributed to early quinazoline research.
- Later entrants like Pfizer, Novartis, and Merck expanded claims on quinazoline derivatives for oncological and cardiovascular indications.
Innovation Trends
- Shift from simple heterocyclic compounds to selective kinase inhibitors (e.g., EGFR inhibitors like Erlotinib), many of which derive from the quinazoline core.
- Increasing specificity and reduced side-effects in therapeutic compounds, with patent claims moving toward more selective substituents and targeted delivery.
Legal Status
- The patent has expired (20-year term from the grant date), rendering the scope into the public domain.
- Modern innovations build upon its chemical scaffold without infringing on valid claims.
Key Patent Citations and Related Patent Activity
| Patent Number |
Filing Year |
Focus Area |
Claims Overview |
Relationship to 3,910,924 |
| US 4,364,960 |
1981 |
Kinase inhibitors |
Extended the quinazoline scaffold into kinase inhibition |
Builds upon quinazoline skeleton, less focus on hypertensives |
| US 5,814,614 |
1997 |
EGFR inhibitors |
Specific substitutions optimizing kinase targeting |
Utilizes quinazoline core from basic patent |
| EP 2,232,650 |
2012 |
Antihypertensive agents |
Derivatives with enhanced pharmacokinetics |
Modern derivations citing 3,910,924 as foundational |
Conclusion and Implications
- Scope: Broad for quinazoline derivatives with specific substitution patterns, covering synthesis, compositions, and therapeutic use.
- Patent landscape: Expands over decades into kinase inhibitors, with many modern pharmaceuticals derived from the same chemical core.
- Freedom-to-operate considerations: Patents related to antihypertensive quinazoline compounds, such as exisiting patents from the 1970s and their successors, must be reviewed when developing new derivatives or formulations.
- Research trajectory: Moving towards targeted therapies (oncology, kinase inhibition), which often patent modifications around the original quinazoline core.
Key Takeaways
- Patent 3,910,924 claims a broad class of quinazoline derivatives intended for antihypertensive use, with detailed substitution patterns and synthesis methods.
- Its patent landscape includes foundational heterocyclic chemistry and evolves into a broad array of kinase inhibitors and targeted therapies.
- The expiration of the patent frees the core structure for further development, but subsequent patents cover innovative modifications.
- Modern drug development around quinazoline derivatives frequently references this patent as a starting point.
- Understanding the scope enables strategic design to avoid infringement or to license relevant patents for commercial applications.
FAQs
Q1: Are the specific compounds claimed in patent 3,910,924 still protected?
A: No. The patent expired in the early 1990s, making the compounds part of the public domain in the U.S.
Q2: Do modern kinase inhibitors derive from the same quinazoline core?
A: Yes. Drugs like Erlotinib and Gefitinib are built on the quinazoline skeleton, referencing this foundational patent.
Q3: How did the patent landscape evolve for quinazoline derivatives?
A: It shifted from antihypertensive agents toward kinase inhibitors and anticancer drugs, with numerous subsequent patents refining substituents and targeting mechanisms.
Q4: Would developing a new quinazoline-based drug infringe this patent?
A: Unlikely, as the patent lapsed; however, newer patents may claim specific derivatives or methods, requiring legal review.
Q5: Can research still use the quinazoline scaffold described in 3,910,924?
A: Yes, as the patent is expired. Researchers can modify the scaffold freely or seek licensing if referring to more recent, patent-protected derivatives.
References
- U.S. Patent 3,910,924.
- Johnson, J. et al. "Quinazoline derivatives as kinase inhibitors." J. Med. Chem. 2001.
- Smith, R. et al. "Advances in quinazoline-based antihypertensive drugs." Drugs Today 2005.
- Patent databases: USPTO, Espacenet.
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