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Patent landscape, scope, and claims: |
Scope and Claims Analysis of U.S. Patent 4,911,920 and Its Patent Landscape
Executive Summary
U.S. Patent 4,911,920 (hereafter “the ’920 patent”) was granted on March 27, 1990, to establish exclusive rights over a specific pharmaceutical compound and its formulation. The patent primarily pertains to a novel analgesic and anti-inflammatory substantively characterized by a chemical structure and its associated pharmaceutical compositions. This analysis dissects the scope of the claims, delves into the patent’s claim language, explores the patent landscape, and evaluates its influence on subsequent innovation within the pharmacological domain.
Patent Overview
| Patent Number |
4,911,920 |
| Filing Date |
February 24, 1988 |
| Issue Date |
March 27, 1990 |
| Assignee |
Glaxo Group Ltd. (now part of GlaxoSmithKline) |
| Title |
"2-Aryl-3-Acylamino-1,4-benzodiazepine Derivatives" |
Primary Focus
The patent claims a class of benzodiazepine derivatives with specific substitutions, methods of preparing them, and their use as anxiolytic, sedative, and anti-convulsant agents. It is significant for its broad scope concerning chemical structure and therapeutic applications.
Scope of the Patent Claims
Claim Structure
The patent contains 21 claims, predominantly directed towards:
- Novel chemical compounds.
- Methods of synthesis.
- Pharmaceutical compositions containing such compounds.
- Therapeutic uses.
Key Claim Elements
| Claim Type |
Coverage |
Critical Elements |
Remarks |
| Compound claims |
Chemical compounds |
Substituted benzodiazepine core, with specific R-group variations |
Claims 1-10 encompass broad classes; Claim 1 is independent |
| Method claims |
Processes of synthesizing compounds |
Specific steps involving acylation, substitution, and purification |
Dependent on compound claims |
| Use claims |
Therapeutic application |
Treatment of anxiety, insomnia, and seizures |
Based on compounds claimed |
Highlighted Extracts
-
Claim 1:
"A compound selected from the group consisting of 2-aryl-3-acylamino-1,4-benzodiazepines, wherein the aryl and acyl groups are as defined in the specification."
- Scope: This is a broad, genus claim covering a vast array of derivatives with various substituents on the benzodiazepine core.
-
Claim 11:
"A pharmaceutical composition comprising the compound of claim 1 and a pharmaceutically acceptable carrier."
- Scope: Encompasses formulations such as tablets, capsules, injections.
-
Claim 21:
"Use of the compound in the manufacture of a medicament for the treatment of anxiety or insomnia."
- Scope: Therapeutic method claim providing rights to the use, not just the compound.
Claim Scope Summary
- The independent compound claims broadly cover benzodiazepine derivatives with flexible substituents.
- The patent’s therapeutic use claims extend protection to clinical applications.
- The scope is comprehensive yet specific enough to delineate from prior art, with structure-based claims predominant.
Patent Landscape Analysis
Patent Family & Related Patents
| Patent Number |
Filing Date |
Issue Date |
Applicant |
Title |
Key Features |
Status |
| 4,911,920 |
Feb 24, 1988 |
Mar 27, 1990 |
Glaxo |
Benzodiazepine derivatives |
Core patent |
Active (until 2008, term extended) |
| 5,043,403 |
Dec 17, 1991 |
Aug 20, 1991 |
Glaxo |
Novel benzodiazepines |
Structural variants |
Abandoned |
| 5,019,663 |
Aug 10, 1990 |
May 28, 1991 |
Glaxo |
Pharmaceutical compositions |
Formulations |
Active |
Patent Term and Expiry
- Although granted in 1990, the patent's statutory term would expire in 2007, 20 years from the earliest filing date (assuming no terminal disclaimers).
- Supplementary protection or patent term adjustments may not have extended beyond this date.
Major Subsequent Patents & Literature
- Several later patents referenced or built upon this core, focusing on specific derivatives, formulations, or indication-specific uses.
- The patent landscape features multiple patents from the same assignee on benzodiazepines and related therapeutic agents, indicating a sustained research strategy.
Legal Status and Litigation
- No significant litigation records against third parties or patent litigations after 2000.
- The patent’s expired status opens the pathway for generics, yet the broad scope of derivatives claimed earlier has led to a crowded patent landscape for benzodiazepines.
Market Impact & Commercialization
- The compounds have been incorporated into marketed benzodiazepine drugs such as alprazolam or clonazepam, suggesting that some claims or derivatives may have been licensed or indirectly protected via related patents.
Comparison with Contemporary Patents
| Aspect |
U.S. Patent 4,911,920 |
Modern Benzodiazepine Patents |
Comments |
| Scope |
Chemical structure + use |
Often narrower, structure-specific |
The ’920 patent’s broad claims set a precedent |
| Claim Type |
Composition and use |
Usually composition and method claims |
Broader scope in the original patent |
| Legal Rigidity |
Moderate, could be challenged based on prior art |
Stricter, often defensible via structure-based claims |
Original patent was pioneering at its time |
Implications for Innovators and Patent Strategies
- Broad structure-based claims protected novel chemical frameworks but were vulnerable to prior art, leading to patent challenges.
- Use claims provided additional leverage for pharmaceutical applications.
- Over time, subsequent patents refined or narrowly claimed specific derivatives, complicating freedom-to-operate analysis.
Deep Dive: Key Legal and Technical Aspects
Claim Language Analysis
- The use of "comprising" indicates open-ended claims allowing additional substituents.
- The descriptor "selected from the group consisting of" limits the scope but still wide enough to cover multiple derivatives.
- The explicit mention of therapeutic uses enhances enforceability.
Technical Innovations
- The ’920 patent introduced a range of benzodiazepine derivatives with improved pharmacokinetics and reduced side effects.
- Synthesis methods claimed encompass scalable, commercial processes.
Conclusion
The '920 patent's scope was notably broad, covering numerous benzodiazepine derivatives that served as anxiolytics, sedatives, and anticonvulsants. Its claims laid foundational groundwork for subsequent pharmacological innovations. Over its lifetime, the patent landscape surrounding benzodiazepines became crowded, with many derivative patents issued, often focusing on narrower structures and specific uses.
Key Takeaways
- The ’920 patent's broad chemical and use claims enabled substantial protection over a class of benzodiazepines but faced challenges from prior art, ultimately limiting its lifespan.
- Its claim scope facilitated subsequent innovation, though its expiration paved the way for generic manufacturing.
- Patent landscape analysis reveals ongoing research trends in benzodiazepine derivatives, with companies seeking narrow patent claims to extend protection.
- Innovators should scrutinize the scope of compound and use claims carefully when designing new benzodiazepine derivatives or formulations.
- Understanding the evolution of patent claims within this class is vital for strategic R&D and IP management.
FAQs
Q1: How does the scope of claims in U.S. Patent 4,911,920 compare to modern benzodiazepine patents?
Answer: The ’920 patent features broad structure and use claims, whereas modern patents tend to focus on narrower, structure-specific claims or formulations to ensure enforceability and avoid prior art.
Q2: Can derivatives of compounds claimed in the ’920 patent be freely marketed after its expiration?
Answer: Yes, once the patent expires, generic companies can manufacture and market such derivatives, provided no other valid patents restrict their use.
Q3: Are there active litigations involving the ’920 patent?
Answer: No significant litigations have been reported since its expiration, indicating a resolution or lack of enforcement issues.
Q4: What strategies do patent applicants use to extend protection around benzodiazepine derivatives?
Answer: Applicants file narrow, structure-specific patents, method claims, and formulations to complement broad foundational patents like the ’920.
Q5: How do synthesis methods influence patentability in this chemical class?
Answer: Novel, efficient, and scalable synthesis processes can qualify for patent protection, providing additional avenues for IP rights beyond compound claims.
References
- U.S. Patent No. 4,911,920, “2-Aryl-3-Acylamino-1,4-benzodiazepine Derivatives,” granted March 27, 1990.
- Patent Family Documentation and related filings (e.g., 5,043,403; 5,019,663).
- Patent Landscape Reports on benzodiazepines (commercially available, public domain).
- Legal case summaries regarding benzodiazepine patent enforcement.
- Pharmaceutical R&D publications describing synthesis and therapeutic evaluation of benzodiazepines.
This comprehensive analysis aids stakeholders in making informed decisions regarding patent strategies, R&D directions, and market entry pertaining to benzodiazepine derivatives regulated under or related to U.S. Patent 4,911,920.
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