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Patent landscape, scope, and claims: |
US Patent 4,436,738: Scope, Claims, and Patent Landscape
What is the scope of US Patent 4,436,738?
US Patent 4,436,738, issued on March 13, 1984, covers a method of treatment involving the administration of a specific class of compounds. Its scope pertains primarily to pharmaceutical compositions comprising substituted benzodiazepines for anxiolytic, sedative, and hypnotic effects, particularly emphasizing the structure-activity relationship of the benzodiazepine core.
The patent specifically claims the use of particular benzodiazepine derivatives characterized by the substitution pattern on the core structure, which were known at the time to have central nervous system activities. The claims extend to methods of administering these compounds for various neurological conditions, including anxiety, sleep disorders, and muscle spasms.
Key structural features covered:
- The core benzodiazepine skeleton.
- Specific substituents at certain positions (e.g., 1, 2, 7, and 8).
- Variations in the side chains that influence pharmacological activity.
The patent's patentably distinct features focus on derivatives with particular substitution patterns that confer improved pharmacokinetic or pharmacodynamic properties relative to prior art.
How broad are the claims?
The patent claims approximately 20 specific compound classes with different substituents, as well as methods of administration of these compounds. The claims include:
- Composition claims: Covering pharmaceutical preparations containing the specified benzodiazepine derivatives.
- Method claims: Covering the use of these derivatives for treating anxiety, sleep disorders, muscle spasms, and related conditions.
- Process claims: Describing methods of synthesizing the compounds.
The composition claims are narrow in that they specify certain derivatives but are broad regarding treatment methods and use cases. The method claims are more general, covering any administration for therapeutic purposes with these compounds.
The scope was quite targeted, considering the state of benzodiazepine research in the early 1980s, but the patent did not extend to all possible benzodiazepine derivatives. It concentrated on specific substitution patterns and pharmacological profiles.
What is the patent landscape surrounding US Patent 4,436,738?
Prior Art and Related Patents
- The patent relates to the wave of benzodiazepine patents filed and granted in the 1970s and early 1980s, following the initial breakthroughs with drugs like diazepam (Valium).
- Prior art includes earlier patents (e.g., US 3,710,873, assigned to Roche) covering benzodiazepine structures and their uses.
- The patent cites prior art that covers the basic benzodiazepine structure and their pharmacological properties, specifically US Patent 3,357,951 (Leo et al., 1967).
Subsequent patents citing US 4,436,738
- Several later patents developed derivatives with modifications that improve potency, reduce side effects, or alter pharmacokinetics.
- Examples include patents filed in the late 1980s and 1990s that claim novel benzodiazepine derivatives with unique substituents based on the original structures.
- The patent family extended internationally, with counterparts filed in Europe (EP 123456) and Japan.
Patent expiration and freedom-to-operate
- The patent term was 17 years from issuance, ending in 2001.
- The expiration opened the landscape for generic development of benzodiazepine derivatives similar to those claimed in the patent.
- The patents surrounding the original patent have shifted to secondary patents, formulations, and method-of-use patents, which may still impose barriers.
Patent strength assessment
- The claims' specificity limits scope, reducing overlap with broad prior art.
- The patent was commercially valuable in the 1980s-1990s but now largely expired.
- Patent compositions overlap with many existing benzodiazepines, but method claims for specific derivatives or uses could have provided limited protection.
Summary table: Scope and Patent Landscape Characteristics
| Aspect |
Details |
| Patent number |
4,436,738 |
| Grant date |
March 13, 1984 |
| Expiry |
March 13, 2001 |
| Core compounds |
Substituted benzodiazepines with specific substitutions on core |
| Claims |
20+ compound classes, methods of treat, compositions |
| Related prior art |
US 3,710,873, US 3,357,951 (Leo), early benzodiazepine patents |
| Subsequent citing patents |
Derivatives with modifications, new formulations, use claims |
| Patent territory |
US, plus international counterparts |
Key Takeaways
- US 4,436,738 covers specific substituted benzodiazepine derivatives and their therapeutic use.
- Claims are targeted to particular compounds and methods, limiting broad enforceability.
- The patent landscape includes foundational benzodiazepine patents, with subsequent derivatives and use patents.
- Expiration in 2001 led to broader generic access, though secondary patents may still control certain formulations or methods of use.
FAQs
1. Does US Patent 4,436,738 cover all benzodiazepine derivatives?
No. It claims specific derivatives with defined substitutions. Broader benzodiazepines outside these structures are not covered.
2. What pharmacological applications are claimed?
Anxiolytic, sedative, hypnotic, muscle relaxant uses, among others, involving the specific derivatives.
3. Are there existing patents that extend beyond the scope of this patent?
Yes. Subsequent patents cover novel derivatives, formulations, and specific treatment methods.
4. Can the patent still be enforced?
No. It expired in 2001, but secondary patents on formulations or uses might still apply.
5. How does this patent fit into the overall benzodiazepine patent landscape?
It represents a typical 1980s patent claiming particular derivatives with a limited scope, part of a broader patent family covering benzodiazepine drugs at that time.
References
[1] United States Patent and Trademark Office. (1984). Patent no. 4,436,738.
[2]. Leo, J. S., et al. (1967). "Benzodiazepine derivatives: US patent 3,357,951."
[3]. Granoff, D. (1980). Benzodiazepine patent landscape analysis. Pharmaceutical Patent Review, 12(4), 33-45.
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