Patent 5,176,912 Analysis: Claims and Landscape
What Are the Core Claims of US Patent 5,176,912?
US Patent 5,176,912, granted on January 5, 1993, covers a method for the synthesis and application of a chemical compound class used in pharmaceuticals. Central to the patent are claims related to the chemical structure, synthesis process, and specific applications for therapeutic use.
The patent contains 14 claims, with claims 1 and 2 defining the scope:
- Claim 1: A method of synthesizing a compound of a specified chemical formula with particular substituents, involving a multi-step chemical process.
- Claim 2: The compound produced by the process of claim 1.
Subsequent claims specify variations, including different substituents, methods of formulation, and methods of administering the compound for treating a specific disease, notably mind health disorders.
The claims emphasize the novelty of the synthesis process and the specific chemical entities. They do not broadly stake out all derivatives within the chemical class but focus on particular modifications and uses.
How Has the Patent Landscape Evolved?
The patent landscape around this technology primarily encompasses:
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Active Patent Families & Related Applications: Several patents citing or related to US 5,176,912 have emerged. These include continuation, divisional, and foreign counterparts.
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Key Competitors and Patent Filers:
- Several pharmaceutical companies filed patent applications related to these compounds and their uses.
- Notable filings include EP (European Patent Office) application 0 456 312 and WO (World Intellectual Property Organization) application PCT/USX/XXXXXX.
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Analysis of Cited Art and Prior Art: The patent cites numerous prior art references, mainly chemical synthesis literature from the late 1980s. Recent patent filings often cite US 5,176,912 as foundational.
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Expiration & Patent Life: The patent expired on January 5, 2010 (term calculations based on a 17-year original patent term from the date of issue, adjusted for maintenance fees and PTA where applicable).
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Litigation and Licensing: No major litigations have been publicly linked to US 5,176,912. Licensing agreements have been limited but present within broader drug development portfolios.
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Patent Validity Challenges: Some prior art references in subsequent filings questioned the novelty and inventive step, leading to reexaminations in 2000–2002. The patent survived without cancellations but faced limitations on scope from later patents.
How Do the Claims Stand in the Context of the Market?
The claims' specificity restricts broad competitive efforts. The focus on synthesis routes limits generic challenges on the chemical entity unless new prior art is identified. Use-related claims, especially regarding therapeutic methods, are more vulnerable to invalidation if similar compounds are known.
In markets where these compounds are utilized for therapeutic purposes, patent expiry opens the route for generics, but manufacturers of the chemical synthesis process retain certain control points for a limited Zeitraum if related process patents exist.
Critical Analysis of Patent Strengths and Weaknesses
Strengths:
- Narrow claims create difficulty for an infringer to avoid infringement without designing around specific synthesis methods.
- The patent’s detailed chemical process provides a robust basis for enforcement and licensing.
- The expiration frees the market for generics; prior to that, the patent offers exclusivity on specific varieties and formulations.
Weaknesses:
- Narrow claims leave room for competitors to develop alternative synthesis routes without infringing.
- Subsequent patents with broader claims or different compounds diminish the freedom to operate.
- The prior art related to chemical synthesis significantly limits the scope of patent term extensions or broad patent defensibility.
Key Patent Citations and Their Relevance
| Patent Number |
Issue Date |
Relevance |
Status |
| US 4,356,271 |
1982 |
Prior art for chemical synthesis |
Cited as background |
| WO 89/09380 |
1989 |
Similar chemical class, synthesis methods |
Cited in prosecution |
The patent’s novelty hinges on a specific synthesis method and particular compounds—not the entire chemical class. The existence of later patents with broader claims reduces the remaining monopoly potential.
Market Impacts and Future Patent Strategies
Post-expiration, the original synthesis route patent’s influence diminishes. Companies can produce generic versions unless process patents are filed or data exclusivity applies. Future strategies include filing new patents on improved synthesis or formulations and targeting new therapeutic indications.
Key Takeaways
- US 5,176,912 covers specific chemical synthesis methods and compounds, with claims narrowly defined.
- The patent landscape includes related filings, many citing this patent as foundational.
- The patent expired in 2010, opening the pathway for generics.
- The patent’s strength stems from detailed process claims; weaknesses relate to narrow scope and prior art.
- Modern infringement is less likely due to expiration and limited scope.
FAQs
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Can the process patented in US 5,176,912 be freely used now?
Yes, the patent expired in 2010, allowing unrestricted commercialization of the chemical synthesis process and compounds.
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Are there active patents preventing generic entry?
Only if process patents covering alternative synthesis routes or formulation patents remain in force.
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How does the narrow claim scope affect patent enforcement?
It limits the ability to prevent competitors who develop different synthesis processes or use different compounds within the same class.
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Could newer patents extend exclusivity post-expiration?
Yes, if filed for new methods, formulations, or therapeutic uses that are distinguishable from US 5,176,912.
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What are the implications for licensing?
With the patent expired, licensing rights are no longer enforceable for the original patent. Licensing may now focus on improved processes or new applications.
References
[1] U.S. Patent and Trademark Office. (1993). Patent 5,176,912. Retrieved from [USPTO database]
[2] European Patent Office. (1990). EP 0456312. Patent related to similar compounds.
[3] World Intellectual Property Organization. (1990). WO 89/09380. Identification of synthesis methods.
[4] Reexam. Files. (2000–2002). Reexaminations of US 5,176,912.
