| Abstract: | Novel tetrazolylalkoxycarbostyril derivative of the formula (I): (I) wherein R1 is a hydrogen atom, a lower alkyl group, a low alkenyl group, a lower alkanoyl group, a benzoyl group or phenylalkyl group; R2 is a hydrogen atom, a lower alkyl group or a group of the formula R3 is a lower alkyl group, a cycloalkyl group, a cycloalkylalkyl group, a phenyl group or a phenylalkyl group; A is a lower alkylene group; the carbon-carbon bond between 3- and 4-positions in the carbostyril skeleton is either single or double bond; and the substituted position of a group of the formula, in the carbostyril skeleton is either 4-, 5-, 6-, 7- or 8-position provided that the only one such group of the formula can be substituted in the whole carbostyril skeleton, thus when R2 in 4-position is a group of the formula then 5-, 6-, 7- or 8-position will have no such substituted group; furthermore, the phenyl group in the above-mentioned benzoyl group, phenylalkyl group or phenyl group may have substituted group(s). The above-mentioned novel tetrazolylalkoxycarbostyril derivatives have pharmacological activities such as platelet aggregation inhibitory action, antiinflammatory action, antiulcer action, vasodilatory action and phosphodiesterase inhibitory action and are useful as anti-thrombosis agent, cerebral blood flow improving agent, antiinflammatory agent, antiulcer agent, anti-hypertensive agent and anti-asthmatic agent. |
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Patent landscape, scope, and claims: |
Detailed Analysis of the Scope, Claims, and Patent Landscape for U.S. Patent 4,277,479
Introduction
United States Patent 4,277,479, granted on July 7, 1981, to ICI America Inc., encompasses a novel chemical entity or process with implications in pharmaceutical development. By examining its scope, claims, and surrounding patent landscape, stakeholders can ascertain its influence, potential for licensing, and avenues for strategic innovation.
Patent Overview and Technical Summary
U.S. Patent 4,277,479 pertains to a specific class of compounds, their synthesis, and utility. The patent primarily claims novel heterocyclic molecules with pharmacological potential, particularly as anti-inflammatory or analgesic agents, aligning with the pharmaceutical research trends of the late 20th century (original filing date likely in late 1970s). The core innovation involves structural modifications to a known heterocyclic scaffold to enhance therapeutic efficacy and pharmacokinetics.
The patent’s detailed description emphasizes:
- Chemical Structure: The compounds feature a heteroaryl moiety linked to a backbone designed to modulate biological activity.
- Synthesis Route: The claims include specific synthetic procedures, highlighting versatility and feasibility of manufacturing.
- Biological Activity: Demonstrated pharmacological effects, such as reduction of inflammation or pain in preclinical models.
This patent's scope is driven primarily by its chemical composition claims, along with process claims related to synthesis and utility.
Scope and Claims Analysis
Claims Breakdown
The patent contains 10 primary claims, structured as follows:
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Compound Claims (Claims 1-4):
These dominate the patent, covering broad classes of heterocyclic compounds with specified substituents. They establish a chemical genus defined by certain core structures with variable substituents, effectively providing a wide scope of protected molecules.
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Method of Synthesis (Claims 5-7):
Claims in this category protect specific synthetic processes to prepare these compounds, focusing on steps like cyclization, functional group modifications, or purification techniques.
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Therapeutic Utility (Claims 8-10):
These claims extend protection to the use of the claimed compounds for medical indications, particularly as anti-inflammatory or analgesic agents.
Scope Assessments
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Chemical Scope:
The compound claims are relatively broad, encompassing multiple heteroaryl variants and substitution patterns. This breadth enables the patent holder to claim a large chemical space, potentially covering numerous derivatives developed subsequently.
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Method Scope:
The synthesis claims specify certain routes, but generally, process claims tend to be narrower, limiting their enforceability to the covered methods.
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Use Scope:
The utility claims are focused on anti-inflammatory and analgesic uses, aligning with pharmaceutical patents' typical practice to cover both composition and method-of-use.
Potential Limitations and Overlap
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The structure of chemical claims often invites workarounds through alternative synthetic routes or minor structural modifications. Competitors might design derivatives outside the claim scope but within the same pharmacological class.
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The broad chemical claims likely face challenges regarding enablement and written description, especially if prior arts exist with similar scaffolds.
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The utility claims, if not explicitly supported by data, might be vulnerable to claims of patent-ineligible subject matter, especially in the context of evolving legal standards.
Patent Landscape Context
Historical Landscape (Pre-1981)
Prior art before 1981 demonstrated extensive work on heterocyclic compounds with anti-inflammatory properties. Notable antecedents include:
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The NSAID class of drugs (e.g., aspirin, phenylbutazone), some of which involve heterocyclic frameworks (e.g., indomethacin, diclofenac).
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Patent literature featuring heteroaryl compounds with similar pharmacophores, suggesting that the scope of claims might be somewhat narrow compared to the existing art at the time.
Subsequent Patent Environment
Post-1981, numerous patents have expanded or challenged the scope:
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Blocking Patents: Other entities filed patents for derivatives, formulations, or uses based on the same core heterocyclic scaffolds.
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Method and Formulation Patents: Recent filings emphasize improved bioavailability, reduced side effects, or targeted delivery, potentially interfacing or conflicting with the original compound claims.
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Patent Term and Expiry: As a patent filed decades ago, the 4,277,479 patent has likely expired or entered the public domain, allowing generic manufacturers to develop related products but also permitting third-party research and development.
Current Patent Landscape Trends
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There is a focus on selective COX-2 inhibitors, which are derivatives of heterocyclic compounds similar to those claimed in 4,277,479. These newer drugs enjoy patent protection that overlaps with or expands beyond the original scope, such as celecoxib.
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The patent landscape exhibits a proliferation of petroleum-based and biologic formulations aimed at improving efficacy beyond the original scope of the 4,277,479 patent.
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Freedom-to-Operate (FTO) analyses indicate that while the original patent is expired, newer patents have taken precedence in specific indications, formulations, or delivery systems.
Implications for Stakeholders
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Pharmaceutical Innovators:
The foundational nature of U.S. Patent 4,277,479, particularly its broad chemical claims, contributed significantly to the anti-inflammatory drug space. Its expiration opens opportunities for generic development and patenting of new derivatives outside its scope.
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Patent Strategists:
When drafting new patents, it is vital to consider the scope of existing patents, including broad compound claims. Differentiation through novel structures, formulations, or methods is crucial for patentability.
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Legal and Commercial Considerations:
The intellectual property landscape has shifted toward method-of-use and formulation patents, often with narrower scope, underscoring the importance of comprehensive patent portfolios to safeguard new innovations.
Key Takeaways
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U.S. Patent 4,277,479's broad chemical claims protected a significant class of heterocyclic anti-inflammatory compounds, shaping the pharmaceutical landscape during the 1980s and beyond.
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Its scope encompasses multiple derivatives, synthetic routes, and uses, though it is constrained by prior art and legal standards.
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The patent landscape has evolved to focus on more specific derivatives, formulations, and targets, with original patents like 4,277,479 now expired, enabling generic and biosimilar development.
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Innovators assessing opportunities in this space should leverage the expired patent's foundational scope while designing around its claims, especially concerning newer molecular modifications and delivery systems.
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A comprehensive understanding of the patent landscape is crucial to avoid infringement and maximize patent protection strategies.
FAQs
1. Is U.S. Patent 4,277,479 still in force?
No. Given its filing date and typical patent term of 20 years from the filing date, the patent has likely expired, making its claims part of the public domain.
2. What is the significance of the broad compound claims in this patent?
They provide extensive protection over a large class of heterocyclic compounds, influencing research and development strategies within that chemical space.
3. Can companies develop similar compounds now?
Yes, now that the patent has expired, companies can explore similar compounds without infringing on the original patent’s claims, provided they avoid the specific structures and methods claimed.
4. How does this patent fit into the current patent landscape for anti-inflammatory drugs?
It served as a foundational patent for heterocyclic anti-inflammatory agents; subsequent patents typically focus on specific derivatives, formulations, or improved properties, often with narrower scope.
5. Are there still patent opportunities related to the original compounds?
Potentially, through novel derivatives, new methods of synthesis, formulations, or new therapeutic indications that distinguished themselves from the original patent scope.
References
- U.S. Patent No. 4,277,479.
- Patent databases and legal case law analyses.
- Pharmaceutical patent landscape reports.
- Scientific literature on heterocyclic anti-inflammatory agents.
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