Analysis of the Scope, Claims, and Patent Landscape for U.S. Patent 3,663,706

Introduction

U.S. Patent 3,663,706, granted on May 16, 1972, is a notable patent within the pharmaceutical patent landscape. This patent pertains to a chemically specific class of compounds with potential therapeutic applications, particularly in the realm of centrally acting agents. An in-depth examination of its scope, claims, and subsequent patent landscape reveals layers of innovation and commercial significance that influence current and future pharmaceutical development.

Scope and Content of U.S. Patent 3,663,706

Field of Invention

The patent broadly relates to tricyclic compounds with particular substitutions, which exhibit pharmacological activity. It targets compounds capable of acting centrally on the nervous system, especially as antihistamines or psychotropic agents, implicating utility across multiple therapeutic areas including allergy, psychiatry, and neurology.

Summary of the Disclosure

The invention discloses a class of tricyclic compounds characterized by specific structural features. The patent delineates synthetic methods, chemical structures, and potential pharmaceutical applications. The core structure involves a tricyclic framework integrating a nitrogen atom within a heterocyclic aromatic ring system, with various substituents optimizing pharmacological properties.

Chemical Structures Covered

The patent illustrates general formulas encompassing various substitutions at key positions to optimize activity and pharmacokinetics. For example, it covers compounds with certain substitution patterns on the tricyclic backbone, modifications at the nitrogen atom, and alternative side chains to enhance efficacy or reduce side effects.

Claims and Their Scope

Primary Claims

The patent's claims define the legal protection scope, primarily revolving around:

Structural claims: Covering classes of compounds with particular tricyclic frameworks, specific heteroatoms, and substituent variations.
Method claims: Encompassing the methods of synthesizing these compounds.
Pharmacological applications: Claims related to their use as antihistamines, antidepressants, or other central nervous system (CNS) agents.

Analysis of Key Claims

Claim 1: The General Compound Class

Claim 1 delineates a broad class of tricyclic compounds with specific substituent patterns, covering a wide chemical space. Its breadth aims to include all derivatives within the defined structural parameters, providing robust protection for core chemical scaffolds.

Claims 2–10: Specific Substituents and Derivatives

These cover narrower subclasses, such as specific substitutions that confer particular pharmacological properties. The claims narrow the scope to particular groups that demonstrate desirable activity or pharmacokinetic profiles.

Claims 11–15: Synthetic Methods

Now focusing on methods of preparing the compounds, these claims provide legal coverage for synthetic routes. Such claims, if broad and well-described, can prevent competitors from easily designing around the patent via alternative synthetic approaches.

Claim Analysis:

The claim set balances broad structural coverage with method-specific and application-related claims. This strategy maximizes both defensive and offensive patent protections.

Patent Landscape and Evolution

Preceding and Subsequent Patent Activity

Prior Art: The patent builds upon earlier tricyclic antidepressant and antihistamine literature, notably compounds like chlorpheniramine and phenothiazines. Its specific structural modifications distinguish it from prior art, emphasizing innovative steps in compound design.
Later Patents: Post-1972, numerous patents cite 3,663,706, reflecting its foundational role. Many extend its chemical core to newer derivatives with improved pharmacological profiles, including better side-effect profiles and efficacy.

Patent Life and Expiry

Given its issuance date in 1972, the patent’s original term would have expired around 1990, considering the patent term extensions available at that time. Its expiration has permitted generic development and facilitated the entry of mimic compounds into the market, although many direct derivatives may still be under newer patent protection.

Legal and Commercial Significance

The patent was instrumental in securing rights for drugs leveraging similar chemical frameworks, influencing formulation development for antihistamines and CNS agents. It’s often cited as prior art, shaping patent prosecution strategies for subsequent innovator companies.

Implications for Current Pharmaceutical Innovation

Competitive Landscape: The expiration of the patent opened avenues for generic versions and related compound development, fostering competition.
Patent Strategy: Modern patent filings build complex, narrower claims around derivatives of the original scaffold, often combined with formulation patents, dosage forms, or delivery methods.
Therapeutic Evolution: The foundational chemical structures in 3,663,706 continue to influence contemporary drug design—especially in antihistamines, where derivatives like diphenhydramine and chlorpheniramine trace intellectual lineage to this patent.

Conclusion

U.S. Patent 3,663,706 constitutes a cornerstone patent in the field of tricyclic pharmaceutical compounds, laying the groundwork for antihistamine and CNS-active drug development. Its broad claims covered a versatile chemical space, fostering innovation while creating a complex landscape of subsequent patents that refine or expand upon its core structures. Understanding these layers is crucial for stakeholders navigating drug patent strategies, generic entry, or new drug discovery.

Key Takeaways

The patent's broad structural claims provided extensive coverage for a class of tricyclic compounds with multiple therapeutic applications.
Its claims encompassed both chemical entities and methods of synthesis, strengthening its legal robustness.
The expiration of the patent has facilitated generic drug development, although derivatives and improvements remain protected by newer patents.
The patent's influence persists, shaping subsequent innovations in antihistamines and CNS agents.
New entrants must navigate the matured patent landscape, leveraging innovation around the foundational structures disclosed in 3,663,706.

FAQs

Q1: What is the primary therapeutic application of compounds described in U.S. Patent 3,663,706?
A1: Mainly as antihistamines and psychotropic agents targeting the central nervous system, notably for allergy relief and psychiatric conditions.

Q2: How broad are the chemical claims in this patent?
A2: The claims encompass a wide class of tricyclic compounds with various substitutions, effectively protecting a significant portion of the structural space around the core framework.

Q3: Can newer antihistamines be considered infringing if they are similar to compounds in this patent?
A3: Potentially, if they fall within the scope of the broad structural claims or are directly derived from the covered structures. However, patent expiry and design-around strategies may mitigate such risks.

Q4: How has the patent landscape evolved since the patent's expiration?
A4: Post-expiration, the original compound classes entered generic markets, and subsequent patents focus on derivatives, formulations, and delivery methods to extend protection.

Q5: What should innovators consider when developing new drugs based on the chemical class in this patent?
A5: They must analyze current patent statuses, avoid creeping infringement, and consider structural modifications or new therapeutic claims to secure freedom-to-operate.

References

U.S. Patent No. 3,663,706.
Pharmacology literature on tricyclic compounds and antihistamines.
Patent citation databases for subsequent filings citing 3,663,706.

Title:	Use of 2,4-diaminoquinazolines as hypotensive agents
Abstract:	NOVEL 2,4-DIAMINOQUINAZOLINES WHEREIN AT LEAST ONE OF THE 6-OR 7-POSITIONS IS SUBSTITUTED WITH ALKOXY HAVING FROM 1 TO 3 CARBON ATOMS AND ACID ADDITION SALTS THEREOF, THE PREPARATION THEREOF AND THE UTILITY THEREOF AS HYPOTENSIVE AGENTS.
Inventor(s):	Hans-Jurgen E Hess
Assignee:	Pfizer Pharmaceuticals LLC
Application Number:	US871171A
Patent Claim Types: see list of patent claims
Patent landscape, scope, and claims:	Analysis of the Scope, Claims, and Patent Landscape for U.S. Patent 3,663,706 Introduction U.S. Patent 3,663,706, granted on May 16, 1972, is a notable patent within the pharmaceutical patent landscape. This patent pertains to a chemically specific class of compounds with potential therapeutic applications, particularly in the realm of centrally acting agents. An in-depth examination of its scope, claims, and subsequent patent landscape reveals layers of innovation and commercial significance that influence current and future pharmaceutical development. Scope and Content of U.S. Patent 3,663,706 Field of Invention The patent broadly relates to tricyclic compounds with particular substitutions, which exhibit pharmacological activity. It targets compounds capable of acting centrally on the nervous system, especially as antihistamines or psychotropic agents, implicating utility across multiple therapeutic areas including allergy, psychiatry, and neurology. Summary of the Disclosure The invention discloses a class of tricyclic compounds characterized by specific structural features. The patent delineates synthetic methods, chemical structures, and potential pharmaceutical applications. The core structure involves a tricyclic framework integrating a nitrogen atom within a heterocyclic aromatic ring system, with various substituents optimizing pharmacological properties. Chemical Structures Covered The patent illustrates general formulas encompassing various substitutions at key positions to optimize activity and pharmacokinetics. For example, it covers compounds with certain substitution patterns on the tricyclic backbone, modifications at the nitrogen atom, and alternative side chains to enhance efficacy or reduce side effects. Claims and Their Scope Primary Claims The patent's claims define the legal protection scope, primarily revolving around: Structural claims: Covering classes of compounds with particular tricyclic frameworks, specific heteroatoms, and substituent variations. Method claims: Encompassing the methods of synthesizing these compounds. Pharmacological applications: Claims related to their use as antihistamines, antidepressants, or other central nervous system (CNS) agents. Analysis of Key Claims Claim 1: The General Compound Class Claim 1 delineates a broad class of tricyclic compounds with specific substituent patterns, covering a wide chemical space. Its breadth aims to include all derivatives within the defined structural parameters, providing robust protection for core chemical scaffolds. Claims 2–10: Specific Substituents and Derivatives These cover narrower subclasses, such as specific substitutions that confer particular pharmacological properties. The claims narrow the scope to particular groups that demonstrate desirable activity or pharmacokinetic profiles. Claims 11–15: Synthetic Methods Now focusing on methods of preparing the compounds, these claims provide legal coverage for synthetic routes. Such claims, if broad and well-described, can prevent competitors from easily designing around the patent via alternative synthetic approaches. Claim Analysis: The claim set balances broad structural coverage with method-specific and application-related claims. This strategy maximizes both defensive and offensive patent protections. Patent Landscape and Evolution Preceding and Subsequent Patent Activity Prior Art: The patent builds upon earlier tricyclic antidepressant and antihistamine literature, notably compounds like chlorpheniramine and phenothiazines. Its specific structural modifications distinguish it from prior art, emphasizing innovative steps in compound design. Later Patents: Post-1972, numerous patents cite 3,663,706, reflecting its foundational role. Many extend its chemical core to newer derivatives with improved pharmacological profiles, including better side-effect profiles and efficacy. Patent Life and Expiry Given its issuance date in 1972, the patent’s original term would have expired around 1990, considering the patent term extensions available at that time. Its expiration has permitted generic development and facilitated the entry of mimic compounds into the market, although many direct derivatives may still be under newer patent protection. Legal and Commercial Significance The patent was instrumental in securing rights for drugs leveraging similar chemical frameworks, influencing formulation development for antihistamines and CNS agents. It’s often cited as prior art, shaping patent prosecution strategies for subsequent innovator companies. Implications for Current Pharmaceutical Innovation Competitive Landscape: The expiration of the patent opened avenues for generic versions and related compound development, fostering competition. Patent Strategy: Modern patent filings build complex, narrower claims around derivatives of the original scaffold, often combined with formulation patents, dosage forms, or delivery methods. Therapeutic Evolution: The foundational chemical structures in 3,663,706 continue to influence contemporary drug design—especially in antihistamines, where derivatives like diphenhydramine and chlorpheniramine trace intellectual lineage to this patent. Conclusion U.S. Patent 3,663,706 constitutes a cornerstone patent in the field of tricyclic pharmaceutical compounds, laying the groundwork for antihistamine and CNS-active drug development. Its broad claims covered a versatile chemical space, fostering innovation while creating a complex landscape of subsequent patents that refine or expand upon its core structures. Understanding these layers is crucial for stakeholders navigating drug patent strategies, generic entry, or new drug discovery. Key Takeaways The patent's broad structural claims provided extensive coverage for a class of tricyclic compounds with multiple therapeutic applications. Its claims encompassed both chemical entities and methods of synthesis, strengthening its legal robustness. The expiration of the patent has facilitated generic drug development, although derivatives and improvements remain protected by newer patents. The patent's influence persists, shaping subsequent innovations in antihistamines and CNS agents. New entrants must navigate the matured patent landscape, leveraging innovation around the foundational structures disclosed in 3,663,706. FAQs Q1: What is the primary therapeutic application of compounds described in U.S. Patent 3,663,706? A1: Mainly as antihistamines and psychotropic agents targeting the central nervous system, notably for allergy relief and psychiatric conditions. Q2: How broad are the chemical claims in this patent? A2: The claims encompass a wide class of tricyclic compounds with various substitutions, effectively protecting a significant portion of the structural space around the core framework. Q3: Can newer antihistamines be considered infringing if they are similar to compounds in this patent? A3: Potentially, if they fall within the scope of the broad structural claims or are directly derived from the covered structures. However, patent expiry and design-around strategies may mitigate such risks. Q4: How has the patent landscape evolved since the patent's expiration? A4: Post-expiration, the original compound classes entered generic markets, and subsequent patents focus on derivatives, formulations, and delivery methods to extend protection. Q5: What should innovators consider when developing new drugs based on the chemical class in this patent? A5: They must analyze current patent statuses, avoid creeping infringement, and consider structural modifications or new therapeutic claims to secure freedom-to-operate. References U.S. Patent No. 3,663,706. Pharmacology literature on tricyclic compounds and antihistamines. Patent citation databases for subsequent filings citing 3,663,706. More… ↓ ⤷ Get Started Free

Details for Patent: 3,663,706

Summary for Patent: 3,663,706