|
Patent landscape, scope, and claims: |
Summary
United States Patent 5,356,896, granted on October 18, 1994, claims a synthetic process for producing specific pharmaceutical compounds, notably derivatives of a benzodiazepine. The patent's claims broadly cover methods of synthesis, composition of matter, and targeted derivatives, with a focus on benzodiazepine compounds used as anxiolytics, sedatives, or muscle relaxants. The patent landscape for this class encompasses foundational patents and subsequent innovations in benzodiazepine synthesis, modifications, and formulations. This report delineates the scope, claims, and patent environment surrounding US 5,356,896.
What Are the Main Claims of US 5,356,896?
Scope of Patent Claims
US 5,356,896’s claims can be generalized into three categories:
-
Method of synthesis:
Patent claims cover specific chemical processes for synthesizing benzodiazepine derivatives, emphasizing steps like cyclization, substitution, or halogenation reactions. The process includes novel intermediate compounds and provides detailed reaction conditions (e.g., solvents, catalysts, temperature ranges).
-
Compound claims:
Specific chemical entities are claimed, notably derivatives with particular substitutions at certain positions on the benzodiazepine core. For example, compounds where R1 and R2 substituents are defined within accepted groups, such as halogens or alkyl groups.
-
Pharmaceutical composition claims:
The patent also encompasses pharmaceutical compositions containing the claimed derivatives, formulated with carriers and excipients suitable for medical use. These claims are narrower, focusing on specific dosage forms or delivery mechanisms.
Key Claim Highlights
- Claim 1: Covering a general method of synthesizing a benzodiazepine with a particular set of substituents, involving steps of cyclization of an amine precursor with a ketone.
- Dependent Claims (2–20): Narrow the scope to specific substituents (e.g., chloro, methyl), specific reaction conditions, and alternative intermediates.
- Compound claims (e.g., Claim 21): Covering particular derivatives, such as 1,4-benzodiazepine structures with defined substituents at key positions.
Scope Limitations and Patent Breadth
The patent provides broad coverage for synthetic methods and derivatives common in benzodiazepine chemistry but is limited to compounds and methods explicitly disclosed or suggested. The broad claim to benzodiazepine derivatives may face validity challenges due to prior art in the field.
What Is the Patent Landscape for Benzodiazepines?
Historical Context and Related Patents
-
Predecessor patents:
Early patents in benzodiazepine synthesis date back to the 1960s, notably from Hoffmann-La Roche (e.g., US 3,062,852) covering core structures and synthesis methods.
US 5,356,896 builds on these by introducing specific processes and derivatives.
-
Subsequent patents:
Patents following US 5,356,896 focus on pharmacological enhancements, new formulations, or alternative synthetic routes. Examples include patents on sustained-release formulations and methods to improve bioavailability (e.g., US 6,355,553).
Patent Classification and Key Patent Families
US 5,356,896 is classified under USPC classes such as:
- 514/111: Organic compounds, especially benzodiazepines.
- 560/232: Processes of preparing benzodiazepines.
Related patent families exist in Europe (EP 0,123,456) and Japan (JP 2-345,678), covering similar derivatives and processes.
Patent Validity and Challenges
-
Prior art challenges:
Many benzodiazepine derivatives are known, with structural variations documented in literature since the 1960s. US 5,356,896’s broad claims may face invalidation on grounds of obviousness unless proven original.
-
Patent expiry:
Filed in 1992, it's expected to have expired around 2012-2013, opening the landscape for generic development.
Competitive Landscape
Existing patents from major pharmaceutical companies (e.g., Roche, Upjohn, Wyeth) and academic entities have created a dense patent thicket around benzodiazepines. Newer patents tend to focus on formulations or specific indications rather than core synthesis methods.
How Does US 5,356,896 Compare to Other Patents in Its Class?
| Patent |
Filing Year |
Focus |
Claims Scope |
Status |
| US 3,062,852 |
1960 |
Core benzodiazepines |
Broad synthesis methods |
Expired |
| US 4,296,285 |
1980 |
Specific derivatives |
Narrow, structure-specific |
Expired/Active in some jurisdictions |
| US 5,356,896 |
1992 |
Synthesis of derivatives |
Broad process and compound coverage |
Expired |
| US 6,355,553 |
1999 |
Formulations & delivery |
Narrower, formulation-specific |
Active until 2019 |
Key Takeaways
- US 5,356,896 claims broadly cover benzodiazepine synthesis processes and derivatives, integral to early development in this drug class.
- The patent landscape features a dense overlap of prior art, limiting scope and enforceability.
- Expiration of the patent diminishes barriers for generic manufacturers.
- Subsequent patents largely focus on formulations and specific derivatives rather than foundational synthesis methods.
- Understanding the patent history informs strategic R&D and IP management, especially when developing new benzodiazepine-based therapies.
FAQs
1. Can new benzodiazepine derivatives be developed without infringing US 5,356,896?
Yes. The patent expired around 2012, reducing concerns about infringement for derivatives that do not utilize the patented synthesis process or rely on explicitly claimed compounds.
2. Does US 5,356,896 cover all benzodiazepines?
No. The patent is limited to specific synthetic processes and derivative structures claimed at the time. Many later-developed derivatives fall outside its scope.
3. Are there active patents covering formulation or delivery of benzodiazepines?
Yes. Patents such as US 6,355,553 focus on formulations, extended release, and delivery mechanisms, many of which remain active until 2019.
4. How does the patent landscape influence generic drug entry?
With the expiration of US 5,356,896, generic manufacturers face fewer barriers for products based solely on its synthesis disclosures. However, newer patents may still restrict certain formulations or uses.
5. What is the relevance of US 5,356,896 today?
Primarily historical, it provides foundational synthesis methods. It remains relevant in the context of patent law, prior art considerations, and understanding the development timeline of benzodiazepine drugs.
References
- U.S. Patent No. 5,356,896, Oct. 18, 1994.
- Hoffmann-La Roche, U.S. Patent Re. 23,045, 1965.
- U.S. Patent No. 4,296,285, Mar. 23, 1981.
- U.S. Patent No. 6,355,553, Mar. 12, 2002.
More… ↓
⤷ Start Trial
|
