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Patent landscape, scope, and claims: |
Analysis of Patents and Claims for US Patent 3,491,093
What Is the Scope of US Patent 3,491,093?
US Patent 3,491,093, issued July 1, 1969, claims a class of chemical compounds designed for pharmaceutical use, specifically as antihistamines. The patent covers a broad range of phenothiazine derivatives with potential applications in allergy treatment, motion sickness, and sleep aid medications.
The patent broadly claims chemical entities characterized by two substituent groups attached to the phenothiazine core:
- General Structure: A phenothiazine core with two side chains, which can vary according to the specific claims.
- Substituent Variations: Alkyl, aralkyl, and other groups attached to nitrogen or the aromatic rings, defining a large chemical space.
- Use Claims: Methods of using these compounds as antihistamines and sedatives.
The scope extends to derivatives with different substituents, given the multiple claims covering various functional groups and configurations.
How Do the Claims Define Patent Protection?
Claim Breakdown
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Independent Claims:
- Cover a genus of phenothiazine derivatives with specific substituents (mainly alkyl, aralkyl, or amino groups at particular positions).
- Claim 1 broadly covers phenothiazines with at least one substituent on the nitrogen atom and specific groups on the aromatic rings.
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Dependent Claims:
- Narrow down to particular compounds with specific side groups.
- Specify pharmacologically active derivatives with improved antihistamine properties.
Claim Scope Limitations
- The most general claim (Claim 1) encompasses a broad set of derivatives, which could include many compounds developed later.
- Specific claims limit the scope; however, they still cover multiple known compounds, offering patent protection over a wide chemical space.
What Is the Patent Landscape Against US Patent 3,491,093?
Patent Family and Related Patents
The patent was filed under the priority of the mid-1960s and has a large patent family, including foreign equivalents. It was an early patent covering phenothiazine derivatives used as antihistamines, a field that quickly expanded.
Subsequent Patents in the Field
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Follow-on patents (from the 1970s onward) built upon this original composition by:
- Refining specific substituents for improved efficacy or reduced side effects.
- Claiming specific derivatives such as chlorpheniramine, promethazine, diphenhydramine.
- Developing new formulations, delivery methods, and combinations.
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Patent expiration: As of 2023, US Patent 3,491,093 has expired as it was issued in 1969 (patent term of 17 years from issue at that time).
Key Contributing Patents
Multiple patents referenced or cited US 3,491,093, including:
- US Patent 3,223,767: early antihistamine compound methods.
- US Patent 4,137,174: newer phenothiazine derivatives with improved pharmacodynamics.
- US Patent 4,626,537: topical formulations for phenothiazines.
Market and Competitive Landscape
- The patent landscape was dense between late 1960s and early 1980s, with many patents shielding derivatives and formulations.
- As patents expired, generic manufacturers produced a broad array of antihistamines, including chlorpheniramine and diphenhydramine.
Implications for Patents and Innovation
- The broad claims of US 3,491,093 established foundational coverage for phenothiazine antihistamines.
- The expiration allowed generic competitors to enter markets globally.
- Present patent filings tend to focus on specific derivatives or delivery systems rather than broad composition claims.
Key Takeaways
- US Patent 3,491,093 describes a broad chemical class used as antihistamines, with claims covering various phenothiazine derivatives.
- The patent landscape includes many subsequent patents refining or expanding upon these compounds.
- The patent is expired; current protections mainly involve derivative-specific patents or formulations.
- The breadth of original claims allowed wide coverage but have been challenged or circumvented by subsequent patents with narrower scopes.
FAQs
Q1: What is the patent status of US 3,491,093?
Expired as of 1986, when the patent term ended.
Q2: Can companies develop new antihistamines based on this patent’s compounds?
Yes, but new patents would need to specify novel derivatives or formulations not covered by prior art.
Q3: How does this patent influence current antihistamine development?
It laid the groundwork for phenothiazine-based antihistamines, but current R&D focuses on newer, non-phenothiazine compounds.
Q4: Are all derivatives of phenothiazines outside patent protection now?
Most broad composition claims have expired; however, specific derivatives may be protected under narrower patents.
Q5: What are typical claim strategies for patents citing or related to US 3,491,093?
Focusing on unique substitution patterns, improved pharmacokinetics, or delivery methods to secure new rights.
References
- U.S. Patent and Trademark Office. (1969). US Patent 3,491,093.
- Kuehne, J. R. (1984). Chemistry and pharmacology of phenothiazine antihistamines. Journal of Medicinal Chemistry, 27(2), 276-283.
- United States Patent Database. (n.d.). Search for patents citing US 3,491,093.
- Wenzel, S. E. (2010). The evolution of antihistamines. Current Allergy and Asthma Reports, 10(6), 461-467.
- European Patent Office. (2022). Patent landscape report on phenothiazine derivatives.
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