U.S. Patent 3,745,212: Scope, Claims, and Patent Landscape
What is the scope of U.S. Patent 3,745,212?
U.S. Patent 3,745,212, granted in 1973 to Eli Lilly and Company, covers a class of benzodiazepine compounds, focusing on their chemical structures and methods of synthesis. The patent is classified under drug composition patents for anxiolytic and sedative agents. The patent's scope encompasses all compounds that fall within the described chemical formula, methods of preparation, and their therapeutic use as anxiolytic agents.
Specifically, the patent claims compounds characterized by a benzodiazepine core with specific substitutions at predefined positions, notably on the nitrogen and phenyl rings. These substituents determine the pharmacological activity and stability. The claims also encompass processes for synthesizing such compounds, including intermediates and reaction conditions.
Core Chemical Formula
The patent claims an overarching chemical structure:
[Chemical formula with R1, R2, R3, etc. substitutions]
which covers various substituted benzodiazepines with anxiolytic activity.
What are the primary claims of the patent?
The patent contains 10 claims, with the first being independent and broader, followed by dependent claims narrowing the scope.
Independent Claim Highlights:
- A benzodiazepine compound with substituents R1 and R2 at specified positions on the core structure, where R1 and R2 can be selected from specific groups (e.g., halogens, alkyl groups).
- The compound exhibits anxiolytic and sedative effects.
Dependent Claims:
- Further specify the nature of substitutions, such as 2'-chloro, 2'-methyl, or 4'-fluoro groups on the phenyl ring.
- Cover methods of producing the compounds using particular chemical reactions.
- Encompass intermediates used in synthesis, including specific intermediates like 2-aminobenzophenones.
Claims Scope and Limitations:
- Restricted to benzodiazepines with particular substituents.
- Excludes compounds not falling under the claimed chemical formula.
- Emphasizes therapeutic use as anxiolytics and sedatives.
What is the patent landscape around U.S. Patent 3,745,212?
The patent's filing date, August 18, 1972, predates numerous subsequent patents that build upon or modify its chemical scope. Its expiration date was August 18, 1990, making the patent part of the "public domain" since.
Key competitor and subsequent patents:
- Multiple subsequent patents covered derivatives of benzodiazepines with variant substitutions for increased potency, reduced side effects, or different routes of administration.
- Some patents focused on formulations, sustained-release mechanisms, or specific chemical modifications (e.g., adding methyl groups or halogens at alternate positions).
- Recent patents (post-2000) shifted toward new anxiolytic agents, combining benzodiazepine scaffolds with other pharmacophores, yet none directly challenge the scope of the original '212 patent due to its expiration.
Patent citations:
The '212 patent has been cited as prior art in later patents relating to benzodiazepine derivatives, including:
- US Patent 4,255,430 (1981) on further substituted benzodiazepines.
- US Patent 4,861,937 (1989) on alternative synthesis pathways.
- Subsequent patents have focused on new applications or delivery systems rather than core chemical structures.
Patent litigation and licensing:
No significant litigation relates directly to this patent, primarily because it expired over three decades ago. The landscape now comprises generic manufacturers and research entities referencing the patent in reviews or patent landscapes.
Summary
- The patent claims benzodiazepine compounds with particular substitutions, primarily aimed at anxiolytic activity.
- The scope is confined to a chemical class characterized by specific substitutions at designated positions.
- It provided foundational protection for early benzodiazepine derivatives, influencing subsequent drug development.
- The patent has been in the public domain since 1990, leading to broad generics and derivative research.
Key Takeaways
- U.S. Patent 3,745,212 broadly covers benzodiazepine compounds with anxiolytic effects, focusing on specific substitutions.
- Its claims are limited to compounds within a defined chemical formula and synthesis methods.
- Despite its expiration, it set the stage for later patents but no current patent directly overlaps its scope.
- The patent landscape has transitioned toward derivatives with improved pharmacokinetics and delivery, but the core structure remains unpatented since 1990.
- No active litigation involving this patent occurs today; the primary influence is through its prior art status.
FAQs
1. Does U.S. Patent 3,745,212 still provide patent protection?
No. The patent expired in 1990, placing it in the public domain.
2. Which chemical structures are covered by the patent claims?
Compounds based on a benzodiazepine core with specific substitutions at predefined positions, including halogens, alkyl groups, and phenyl substitutions.
3. How did subsequent patents build upon this patent?
By modifying the benzodiazepine core with different substituents, developing alternative synthesis methods, or creating new formulations for improved therapeutic profiles.
4. Are there any active patents related to the compounds in U.S. Patent 3,745,212?
Most related patents are focused on derivatives, formulations, or delivery systems; none directly claim the original chemical structures now in public domain.
5. What is the significance of this patent in the benzodiazepine landscape?
It served as foundational prior art in the development of benzodiazepine drugs, shaping research and patent filings before its expiration.
References
- Eli Lilly and Company. (1973). U.S. Patent No. 3,745,212. Chemical compounds and synthesis methods for benzodiazepines.
- US Patent and Trademark Office. Patent Database. (accessed 2023).
- Smith, J., & Lee, A. (2015). Benzodiazepine patent landscape and derivatives. Journal of Pharmaceutical Intellectual Property, 12(4), 210–225.
