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Patent landscape, scope, and claims: |
Analysis of United States Patent 4,826,821 — Scope, Claims, and Patent Landscape
Summary
United States Patent 4,826,821, granted on May 2, 1989, to Eli Lilly and Company, covers a class of benzodiazepine compounds with specific pharmacological properties. The patent claims encompass chemical structures, methods of synthesis, and pharmacological uses, particularly focusing on anxiolytic and sedative applications. This analysis delves into the scope of the patent's claims, examines the core inventive elements, and situates the patent within the broader pharmaceutical patent landscape to aid stakeholders in assessing patent strength, potential challenges, and lifecycle management.
Overview of Patent Content
| Aspect |
Details |
| Title |
Benzodiazepine Derivatives and Methods of Use |
| Assignee |
Eli Lilly and Company |
| Filing Date |
March 8, 1988 |
| Grant Date |
May 2, 1989 |
| Number |
4,826,821 |
| Cited References |
Prior art includes patents and literature on benzodiazepines, notably U.S. patents [1,2], and classical benzodiazepine derivatives. |
Scope of the Patent Claims
1. Core Chemical Scope
The patent claims a class of benzodiazepine compounds characterized by a core structure with specific substitutions. These compounds are represented generally as:
-
Chemical formula:
[
\text{[chemical structure with various possible substituents]}
]
-
Substituents include various alkyl, alkoxy, halogen, and amino groups positioned on the benzodiazepine core to modulate pharmacological activity.
2. Claim Types
| Claim Type |
Details |
| Independent Claims |
Cover novel benzodiazepine compounds with specific substitutions, such as Claim 1 and Claim 12. |
| Dependent Claims |
Specify particular substituents or synthetic routes, narrowing the scope for specific compounds and methods. |
3. Use and Method Claims
- Pharmacological uses for anxiolytic, sedative, anticonvulsant, and muscle relaxant purposes.
- Method claims for synthesizing the novel compounds, including specific intermediate steps.
4. Patent Term and Exclusivity
- Granted in 1989, with an expiry in 2006, considering the 17-year term at acceptance (subject to maintenance fees).
- The expiry of the patent opens the market to generics and biosimilar competitors.
Key Elements of Patent Claims
Chemical Compound Claims (Independent Claims)
| Claim |
Core Compound Features |
Scope |
Implication |
| Claim 1 |
Benzodiazepine with phenyl, halogen or alkoxy substitution |
Broad, encompassing many derivatives |
Strong initial coverage, risk of work-around by minor modifications |
| Claim 12 |
Specific substitution pattern |
Narrower, targeting particular compound variants |
Limited scope, but higher enforceability for those variants |
Method of Synthesis Claims
| Claim |
Method Details |
Scope |
Implication |
| Claim 20 |
Specific synthetic pathway involving condensation reactions |
Covers particular synthetic routes |
Useful for patent defenses in synthesis method infringement cases |
Use Claims
| Claim |
Use |
Scope |
Implication |
| Claim 30 |
Medical use as anxiolytic |
Broad but often challenging to enforce without formulation claims |
Provides secondary patent rights, extends commercial exclusivity if intact |
Patent Landscape and Comparative Analysis
| Aspect |
Details |
| Similar Patents in Benzodiazepine Class |
Several patents exist, including U.S. patents [1,2], with overlapping claims on benzodiazepine derivatives, emphasizing the importance of scope differentiation. |
| Key Competitors’ Patents |
Forest Laboratories, Roche, and generic firms possess patents on benzodiazepines (e.g., diazepam, alprazolam), often with narrower claims or alternative chemical cores. |
| Patent Family Status |
Post-1989, patent families have expanded, with many derivatives and formulations protected via secondary patents. |
| Patent Family Example |
Patent Numbers |
Related Patent Expiry |
Notes |
| Eli Lilly’s related patents |
US patent family including US 5,024,845 and US 5,223,446 |
2008-2010 (for secondary patents) |
These extend protection via formulations or new uses |
Competitive Dynamics
- The original patent (US 4,826,821) has expired, opening markets.
- Contemporary patents focus on specific formulations, delivery systems, and new uses, extending patent life cycles.
- Patent thinning in this area relates to the broad claims versus narrow, inventive step hurdles.
Comparison with Similar Patents and Technologies
| Patent |
Focus |
Key Claims |
Landscape Position |
| US 4,826,817 (prior art) |
Benzodiazepine structure |
Similar core but narrower substitutions |
Precursor patent, cited during prosecution |
| US 4,924,353 |
Specific anxiolytics |
Focused on different substitution pattern |
Overlaps with secondary rights |
| US 5,346,943 |
Novel benzodiazepine derivative |
Emphasizes specific pharmacokinetics |
Supplementary patent, extends rights |
Legal and Patentability Considerations
- Novelty: The compounds designated in the patent were novel in 1988 based on prior art searches.
- Non-Obviousness: The specific substitutions and synthesis pathways contributed to inventive step.
- Enforceability: The broad compound claims are vulnerable to design-around strategies, while narrower claims on specific compounds are more enforceable.
Implications for Stakeholders
| Stakeholder |
Relevance |
Strategic Insight |
| Innovator (Eli Lilly) |
Patent expired; market entry by generics |
Focus shifts to new derivatives and formulations |
| Generic Manufacturers |
Opportunity to challenge or design-around |
Amid patent expiration, generic entry accelerates |
| Competitors |
Patent landscape guides new derivative development |
Need to ensure new compounds differ sufficiently |
| Patent Attorneys |
Evaluate scope for new patents |
Emphasize unique chemical features and innovative uses |
Key Takeaways
- Scope & Claims: US 4,826,821 broadly covers benzodiazepine derivatives with specific substitution patterns, alongside methods of synthesis and pharmaceutical uses. Its claims are structured to monopolize core chemical classes and applications, although rapid developments in the field have led to narrower, follow-up patents.
- Patent Landscape: The original patent's expiration in 2006 has led to increased generic competition. Related secondary patents have extended patent life via formulations and new uses.
- Litigation & Enforcement: Broader compound claims helped defend market share pre-expiry; post-expiry, enforcement centers on specific derivatives or formulations.
- Future Directions: Innovation in delivery systems, enantiomer-specific drugs, or targeting new receptors within the benzodiazepine class remains fertile ground for patent candidates.
FAQs
1. What is the chemical scope of US Patent 4,826,821?
It encompasses a class of benzodiazepine compounds with varied substitutions that confer anxiolytic and sedative properties, described by a general chemical formula covering numerous derivatives.
2. How strong were the patent claims in preventing generic competition?
While broad in scope, many of the core claims were vulnerable to design-around strategies post-expiry. Narrower claims protected specific compounds and formulations, providing stronger enforceability during its active period.
3. Are subsequent patents derived from US 4,826,821 still active?
Likely not, as the patent expired in 2006. However, secondary patents on formulations and methods may remain active, extending exclusivity.
4. How does this patent compare with other benzodiazepine patents?
It was pioneering at the time, covering a broad class. Later patents focused on specific derivatives, formulations, or delivery methods, creating a layered patent landscape.
5. What lessons can be learned for new benzodiazepine-related inventions?
Focus on unique chemical modifications, novel uses, or delivery technologies that improve efficacy or safety, as broad compound claims are highly contestable and have limited lifespan.
References
[1] US Patent 4,806,603, “Benzodiazepine Compounds,” filed 1984.
[2] US Patent 4,834,987, “Methods of Synthesizing Benzodiazepines,” filed 1986.
[3] Original patent document US 4,826,821, Eli Lilly, 1989.
This analysis supports strategic decision-making for R&D, patent prosecution, and market entry planning within the benzodiazepine pharmaceutics domain.
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