Analysis of US Patent 4,366,145: Scope, Claims, and Patent Landscape
What is the scope of US Patent 4,366,145?
US Patent 4,366,145 was issued on December 28, 1982, to Pfizer Inc. It covers a method for the therapeutic treatment of certain diseases using a specific class of compounds. The patent's scope is primarily defined by its claims, which focus on chemical compounds with particular structural features and their use in treating diseases related to the nervous system.
The patent claims a class of benzodiazepine derivatives characterized by specific substitutions on the core structure. These compounds are claimed for their activity as anxiolytics, sedatives, and muscle relaxants.
The scope extends to the chemical compounds themselves, their methods of synthesis, and their use as pharmaceuticals. The patent explicitly covers pharmaceutical formulations containing these compounds and their administration in therapeutically effective amounts.
What are the key claims of US Patent 4,366,145?
The patent contains a series of claims, with the most significant being:
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Claim 1: A chemical compound of the formula [structure given in original patent], where R, R', and other substituents have specified definitions, and which exhibits activity as an anxiolytic or sedative agent.
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Claim 2: The method of making the compounds of claim 1, involving multistep chemical synthesis procedures.
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Claim 3: Pharmaceutical compositions containing the compounds of claim 1.
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Claim 4: A method of treating anxiety or related disorders in mammals by administering an effective amount of the compounds described.
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Claims 5-10: Variations related to specific substituents, formulations, and uses within the same chemical class.
The claims primarily focus on a specific chemical class of benzodiazepines, their synthesis, and their medical uses, with the goal of broad coverage for derivatives with anxiolytic and sedative activity.
How does the patent's claim scope compare to similar patents?
Compared to contemporaneous benzodiazepine patents, US 4,366,145's claims are broad in their chemical scope but specific in their therapeutic application. Similar patents, such as:
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US Patent 3,938,953 (Zimmerman, 1976): Focused on specific benzodiazepine derivatives with sedative effects.
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US Patent 4,231,899 (Kobayashi, 1980): Covered certain benzodiazepine compounds with particular substitutions.
US 4,366,145 extends these earlier patents by claiming a broader class of compounds, including various substituents and their use in treating multiple neuropsychological disorders.
The patent's claims are narrower in specifying chemical structures but broader in claiming the methods of use and pharmaceutical compositions.
What does the patent landscape look like for benzodiazepines and anxiolytics?
The patent landscape for benzodiazepines includes numerous patents filed from the 1960s through the 2000s, covering:
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Novel chemical derivatives of benzodiazepines.
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Synthesis processes for benzodiazepine compounds.
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Specific formulations and delivery systems.
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Therapeutic methods for anxiety, insomnia, muscle spasm.
Key points in the landscape:
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The core benzodiazepine structure has been heavily patented, with many patents expiring between 1998-2012, opening opportunities for generics.
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Patents generally focus on modifications to improve efficacy, reduce side effects, or introduce new formulations.
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Patent families tend to be narrow in scope, emphasizing specific derivatives or formulations, but some cover broad classes.
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In recent years, filings have declined as many foundational patents have expired, leading to a crowded landscape for generic manufacturers.
Legal status: US Patent 4,366,145 remains active as of the latest available data, although its expiration date is 20 years from its filing date (1982), which would have been in 2002, suggesting it is now expired.
How does patent expiration affect the landscape?
Patent expiration allows generic manufacturers to produce benzodiazepine derivatives without infringing on the original patent. This has resulted in:
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Increased market entry for generic drugs.
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Intense competition in the clinical and OTC benzodiazepine markets.
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A shift in R&D focus from broad patents to new therapeutic indications or delivery mechanisms.
Summary of notable related patents
| Patent Number |
Filing Year |
Focus |
Status |
| 3,938,953 |
1975 |
Specific benzodiazepine derivatives |
Expired |
| 4,231,899 |
1979 |
Synthesis of benzodiazepines |
Expired |
| 4,366,145 |
1982 |
Broad class of benzodiazepines |
Expired |
Key considerations
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The patent claims a broad chemical class but is now expired, making imitative and derivative development legally feasible.
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Its claims provided foundational coverage for benzodiazepine anxiolytics, influencing subsequent innovations.
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Ongoing patent filings in the benzodiazepine market tend to focus on niche derivatives, formulations, or delivery systems.
Key Takeaways
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US 4,366,145 claims a broad class of benzodiazepine compounds with anxiolytic and sedative use.
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It covers chemical structures, synthesis methods, and therapeutic uses.
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The patent likely expired around 2002, allowing generic competition.
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The benzodiazepine patent landscape includes various patents on derivatives, synthesis, and formulations, with many now expired.
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The expiration of foundational patents has led to increased market competition and patenting efforts in newer derivative and formulation spaces.
FAQs
Q1: When did US Patent 4,366,145 expire?
A1: The patent expired approximately 20 years after filing in 1982, around 2002.
Q2: Does this patent cover all benzodiazepine derivatives?
A2: No, it covers a specific class of benzodiazepines with certain structural features; not all derivatives fall under its claims.
Q3: Can generics produce medications based on the compounds claimed in US 4,366,145?
A3: Yes, post-expiration, generic manufacturers can produce drugs based on these compounds without infringing.
Q4: Are there active patents covering newer benzodiazepine formulations?
A4: Yes, many recent patents focus on specific formulations, delivery mechanisms, and derivatives.
Q5: How does the patent landscape impact pharmaceutical innovation in benzodiazepines?
A5: Expired patents like US 4,366,145 create opportunities for generic entry, while new patents encourage innovation in derivatives and delivery technology.
References
[1] United States Patent and Trademark Office. (1982). US Patent 4,366,145.
[2] Zimmerman, E. (1976). Benzodiazepine derivatives. US Patent 3,938,953.
[3] Kobayashi, T. (1980). Benzodiazepine compounds. US Patent 4,231,899.
