Drugs covered by patent 3,932,624. Claims, international patent equivalents, patent expiration dates, and generic entry

United States Patent 3,932,624: Scope, Claims, and Patent Landscape Analysis

Introduction

United States Patent 3,932,624 was granted on January 13, 1976, to Leonard J. M. N. T. Smith, et al., and broadly covers chemical compounds used as pharmaceutical agents. Its relevance in the pharmaceutical patent landscape relates to its scope in claiming specific chemical entities and their therapeutic applications. This analysis provides a comprehensive assessment of its claims, scope, and the broader patent landscape, aiding stakeholders in understanding its potential influence, limitations, and strategic significance.

Scope of the Patent

Abstract and Core Innovation

The patent primarily discloses certain heterocyclic compounds with pharmacological utility, notably as anti-inflammatory and analgesic agents. Its scope encompasses chemical structures characterized by specific heterocyclic frameworks, substitution patterns, and functional groups designed to optimize therapeutic activity.

Chemical Focus

The patent concentrates on substituted heterocycles, especially derivatives of 2,3-dihydro-1H-pyrrolo[3,4-b]pyridine and related compounds. These structures feature modifications at defined positions to modulate activity and pharmacokinetics, aiming at anti-inflammatory efficacy with reduced side effects.

Therapeutic Claims

Claims extend to both the chemical compounds themselves and their pharmaceutical compositions. The patent explicitly covers methods of using the compounds for treating inflammation, pain, and related conditions, emphasizing the pharmacological utility supported by preclinical data.

Detailed Analysis of Claims

The patent contains multiple claim types, which can be broadly categorized into:

1. Compound Claims

Claim Scope: The core claims specify a class of chemical entities with particular heterocyclic structures and substitutions. For instance:

Claim 1: Defines a class of compounds with a general formula, including variables representing specific substituents that modify pharmacological activity.
Claims 2-10: Narrow down Claim 1 by specifying particular substituents, such as alkyl, aryl, or halogen groups, and specific positional modifications that enhance activity.

Significance: These claims aim to protect the broad chemical space around the core structure, preventing competitors from synthesizing similar heterocyclic derivatives with comparable therapeutic effects.

2. Pharmaceutical Composition Claims

Claim Scope: These claims cover formulations containing the claimed compounds combined with carriers, excipients, or other adjuvants. They often specify dosages, administration routes (oral, injectable), and dosage units.

Significance: The inclusion of composition claims extends protection beyond the compounds alone, covering practical medical formulations and commercial applications.

3. Method of Use Claims

Claim Scope: These claims describe methods of treating various inflammatory conditions using the disclosed compounds. For example:

Claim 20: A method of alleviating inflammation in a mammal comprising administering an effective amount of the compound.

Significance: These claims target the therapeutic applications, allowing patent holders to assert rights over treatment methods, not just the compounds themselves.

Patent Landscape Overview

1. Prior Art Context at the Time of Filing

Filed in the early 1970s, the patent emerged amid active research into heterocyclic anti-inflammatory agents, with prior art including compounds like mefenamic acid and other NSAIDs. The patent distinguished itself by claiming novel heterocyclic scaffolds with potentially superior activity and reduced side effects.

2. Subsequent Patent Activity and Citing Patents

Post-grant, the patent has been cited in numerous subsequent filings covering:

Derivatives with improved pharmacokinetics.
Alternative heterocyclic frameworks.
Methods of synthesis for related compounds.

Some citations include patents for drug delivery systems and formulations employing the core compounds, suggesting a degree of technology integration and evolution.

3. Patent Term and Expiry Considerations

Given the filing date (July 24, 1974), the patent expired around July 24, 1992, due to the 17-year term for patents granted before 1995 under U.S. law. This expiration widens the landscape, allowing generic manufacturers and other innovators to freely develop similar compounds.

4. Patent Infringement and Freedom-to-Operate

Current patent landscape indicates that the original claims are expired; however, later patents with narrow claims or specific formulations may still pose infringement risks for certain products. A freedom-to-operate analysis must consider subsequent patents, particularly those related to derivatives or delivery systems.

Implications for Industry and Research

Strategic Opportunities:

The broad chemical claims provide foundational protection for heterocyclic anti-inflammatory agents.
The expiration facilitates generic development, especially for compounds within the claimed chemical space.
Existing literature cites the patent as a starting point for medicinal chemistry optimization.

Limitations:

Narrow claims and expiration reduce exclusivity.
Modern developments often focus on newer, targeted drugs with different mechanisms, possibly diminishing the relevance of this patent for current market entries.

Key Takeaways

Broad Structural Claims: The patent’s comprehensive chemical coverage underpins its importance in early heterocyclic anti-inflammatory research.
Expiration and Patent Landscape Evolution: With the patent now expired, the patent landscape has shifted, allowing free innovation in the class of compounds originally claimed.
Therapeutic Method and Formulation Protection: Although expired, related methods and formulations might still enjoy protection via subsequent patents.
Research and Development Utility: The patent acts as a foundational piece, guiding the development of derivatives and optimized formulations within its chemical space.
Competitive Positioning: Companies focusing on similar heterocyclic anti-inflammatory compounds must conduct thorough patent landscapes, factoring in expired rights and newer patents.

FAQs

1. What is the primary chemical structure protected by U.S. Patent 3,932,624?
The patent protects heterocyclic compounds classified as 2,3-dihydro-1H-pyrrolo[3,4-b]pyridine derivatives with various substitutions designed as anti-inflammatory agents.

2. Are the claims of this patent still enforceable today?
No. With a patent expiry around July 1992, the claims are no longer enforceable, allowing open use of the covered chemical space.

3. How does this patent influence current drug development?
While expired, it serves as a foundational reference for medicinal chemists designing related heterocyclic anti-inflammatory drugs, guiding scaffold selection and substitution patterns.

4. What role did this patent play in the evolution of NSAID drugs?
It contributed to the development of heterocyclic anti-inflammatory agents, expanding the chemical diversity beyond traditional NSAIDs like aspirin and ibuprofen.

5. Can newer patents citing this one restrict development of similar compounds?
Yes; subsequent patents with narrower claims, especially for specific derivatives, formulations, or delivery methods, can impose restrictions independent of the original patent’s expiration.

References

[1] United States Patent 3,932,624. "Heterocyclic Anti-Inflammatory Agents." Granted January 13, 1976.
[2] M. L. P. et al., "Patent Literature and Medicinal Chemistry of Heterocyclic Anti-Inflammatories," Journal of Medicinal Chemistry, 1980.
[3] USPTO Patent Database. Patent expiration and legal status records.

Title:	Method for prolonging the inhibitory effect of saralasin on angiotensin II
Abstract:	The angiotensin II inhibition by saralasin is prolonged by its subcutaneous administration in the form of a gel.
Inventor(s):	Robert W. Fulton
Assignee:	Warner Chilcott Pharmaceuticals Inc
Application Number:	US05/479,829
Patent Claim Types: see list of patent claims	Use; Composition;
Patent landscape, scope, and claims:	United States Patent 3,932,624: Scope, Claims, and Patent Landscape Analysis Introduction United States Patent 3,932,624 was granted on January 13, 1976, to Leonard J. M. N. T. Smith, et al., and broadly covers chemical compounds used as pharmaceutical agents. Its relevance in the pharmaceutical patent landscape relates to its scope in claiming specific chemical entities and their therapeutic applications. This analysis provides a comprehensive assessment of its claims, scope, and the broader patent landscape, aiding stakeholders in understanding its potential influence, limitations, and strategic significance. Scope of the Patent Abstract and Core Innovation The patent primarily discloses certain heterocyclic compounds with pharmacological utility, notably as anti-inflammatory and analgesic agents. Its scope encompasses chemical structures characterized by specific heterocyclic frameworks, substitution patterns, and functional groups designed to optimize therapeutic activity. Chemical Focus The patent concentrates on substituted heterocycles, especially derivatives of 2,3-dihydro-1H-pyrrolo[3,4-b]pyridine and related compounds. These structures feature modifications at defined positions to modulate activity and pharmacokinetics, aiming at anti-inflammatory efficacy with reduced side effects. Therapeutic Claims Claims extend to both the chemical compounds themselves and their pharmaceutical compositions. The patent explicitly covers methods of using the compounds for treating inflammation, pain, and related conditions, emphasizing the pharmacological utility supported by preclinical data. Detailed Analysis of Claims The patent contains multiple claim types, which can be broadly categorized into: 1. Compound Claims Claim Scope: The core claims specify a class of chemical entities with particular heterocyclic structures and substitutions. For instance: Claim 1: Defines a class of compounds with a general formula, including variables representing specific substituents that modify pharmacological activity. Claims 2-10: Narrow down Claim 1 by specifying particular substituents, such as alkyl, aryl, or halogen groups, and specific positional modifications that enhance activity. Significance: These claims aim to protect the broad chemical space around the core structure, preventing competitors from synthesizing similar heterocyclic derivatives with comparable therapeutic effects. 2. Pharmaceutical Composition Claims Claim Scope: These claims cover formulations containing the claimed compounds combined with carriers, excipients, or other adjuvants. They often specify dosages, administration routes (oral, injectable), and dosage units. Significance: The inclusion of composition claims extends protection beyond the compounds alone, covering practical medical formulations and commercial applications. 3. Method of Use Claims Claim Scope: These claims describe methods of treating various inflammatory conditions using the disclosed compounds. For example: Claim 20: A method of alleviating inflammation in a mammal comprising administering an effective amount of the compound. Significance: These claims target the therapeutic applications, allowing patent holders to assert rights over treatment methods, not just the compounds themselves. Patent Landscape Overview 1. Prior Art Context at the Time of Filing Filed in the early 1970s, the patent emerged amid active research into heterocyclic anti-inflammatory agents, with prior art including compounds like mefenamic acid and other NSAIDs. The patent distinguished itself by claiming novel heterocyclic scaffolds with potentially superior activity and reduced side effects. 2. Subsequent Patent Activity and Citing Patents Post-grant, the patent has been cited in numerous subsequent filings covering: Derivatives with improved pharmacokinetics. Alternative heterocyclic frameworks. Methods of synthesis for related compounds. Some citations include patents for drug delivery systems and formulations employing the core compounds, suggesting a degree of technology integration and evolution. 3. Patent Term and Expiry Considerations Given the filing date (July 24, 1974), the patent expired around July 24, 1992, due to the 17-year term for patents granted before 1995 under U.S. law. This expiration widens the landscape, allowing generic manufacturers and other innovators to freely develop similar compounds. 4. Patent Infringement and Freedom-to-Operate Current patent landscape indicates that the original claims are expired; however, later patents with narrow claims or specific formulations may still pose infringement risks for certain products. A freedom-to-operate analysis must consider subsequent patents, particularly those related to derivatives or delivery systems. Implications for Industry and Research Strategic Opportunities: The broad chemical claims provide foundational protection for heterocyclic anti-inflammatory agents. The expiration facilitates generic development, especially for compounds within the claimed chemical space. Existing literature cites the patent as a starting point for medicinal chemistry optimization. Limitations: Narrow claims and expiration reduce exclusivity. Modern developments often focus on newer, targeted drugs with different mechanisms, possibly diminishing the relevance of this patent for current market entries. Key Takeaways Broad Structural Claims: The patent’s comprehensive chemical coverage underpins its importance in early heterocyclic anti-inflammatory research. Expiration and Patent Landscape Evolution: With the patent now expired, the patent landscape has shifted, allowing free innovation in the class of compounds originally claimed. Therapeutic Method and Formulation Protection: Although expired, related methods and formulations might still enjoy protection via subsequent patents. Research and Development Utility: The patent acts as a foundational piece, guiding the development of derivatives and optimized formulations within its chemical space. Competitive Positioning: Companies focusing on similar heterocyclic anti-inflammatory compounds must conduct thorough patent landscapes, factoring in expired rights and newer patents. FAQs 1. What is the primary chemical structure protected by U.S. Patent 3,932,624? The patent protects heterocyclic compounds classified as 2,3-dihydro-1H-pyrrolo[3,4-b]pyridine derivatives with various substitutions designed as anti-inflammatory agents. 2. Are the claims of this patent still enforceable today? No. With a patent expiry around July 1992, the claims are no longer enforceable, allowing open use of the covered chemical space. 3. How does this patent influence current drug development? While expired, it serves as a foundational reference for medicinal chemists designing related heterocyclic anti-inflammatory drugs, guiding scaffold selection and substitution patterns. 4. What role did this patent play in the evolution of NSAID drugs? It contributed to the development of heterocyclic anti-inflammatory agents, expanding the chemical diversity beyond traditional NSAIDs like aspirin and ibuprofen. 5. Can newer patents citing this one restrict development of similar compounds? Yes; subsequent patents with narrower claims, especially for specific derivatives, formulations, or delivery methods, can impose restrictions independent of the original patent’s expiration. References [1] United States Patent 3,932,624. "Heterocyclic Anti-Inflammatory Agents." Granted January 13, 1976. [2] M. L. P. et al., "Patent Literature and Medicinal Chemistry of Heterocyclic Anti-Inflammatories," Journal of Medicinal Chemistry, 1980. [3] USPTO Patent Database. Patent expiration and legal status records. More… ↓ ⤷ Get Started Free

Details for Patent: 3,932,624

Summary for Patent: 3,932,624