US Patent 3,169,424: Scope, Claims, and Patent Landscape Analysis
Overview
United States Patent 3,169,424 was granted on February 16, 1965, to Reuben S. B. and David M. for a synthetic drug composition, specifically pertaining to certain derivatives of barbituric acid. The patent claims a new class of barbiturates with potential sedative and hypnotic applications.
Scope of the Patent
The patent claims cover a series of chemical compounds defined by a particular structure, including a substituted phenyl group attached to the barbituric core. The scope extends to the synthesis and application of these derivatives, emphasizing those with specific pharmacological properties, such as central nervous system depression.
The patent predominantly covers:
- The chemical structure of substituted phenyl derivatives of barbituric acid.
- Methods for preparing such derivatives.
- Their potential therapeutic use as sedatives or hypnotics.
Claims Breakdown
The patent contains 17 claims, primarily covering:
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Compound Claims: Specific chemical structures, including various substituents on the phenyl ring attached to the barbituric backbone. Claims specify particular R groups, such as methyl, chloro, or nitro groups, and particular positions on the phenyl ring.
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Method Claims: Processes for synthesizing these derivatives, including steps involving the reaction of substituted urea derivatives with malonic acid derivatives.
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Use Claims: Application of these compounds as sedative agents for medical purposes.
A notable aspect is the breadth of the compound claims, which encompass a wide range of possible substitutions, effectively patenting a chemical class rather than a singular compound.
Key Claims
- Claim 1: A compound characterized by a substituted phenyl group attached to a barbituric acid core, with specific R substituents.
- Claims 2-17: Cover various specific substituents, methods of synthesis, and medicinal uses.
Patent Landscape and Strategic Positioning
Historical Context
Filed in 1962, the patent falls into a period of active development in centrally acting sedatives and anxiolytics, driven by the medical need for effective sleep aids. It was assigned to Lederle Laboratories, which was actively patenting compounds in the barbiturate class during this era.
Patent Family and Related Patents
The patent is part of a larger portfolio encompassing barbiturates and structurally related derivatives. Its broad chemical claims overlap with subsequent patents in the sedative/hypnotic space, leading to potential patent thickets.
Competitive Landscape
- Many subsequent patents have claimed modifications of the barbiturate skeleton, including those targeting improved safety profiles.
- Compound patents tend to be narrow; the broad claims of this patent could have been designed to prevent competitors from synthesizing similar derivatives within the defined structural class.
- Other key patents in the 1960s cover non-barbiturate sedatives, such as benzodiazepines.
Legal Status and Valuation
As of 2023, US Patent 3,169,424 has long expired (patents generally last 17 years from issuance for patents filed before 1995, or 20 years from filing). The expiration date predates modern patent term adjustments, with the patent expiring in 1983. Therefore, the patent offers no enforceable rights currently.
However, its expired status does not diminish the influence of its structural claims, which shape the scope of barbiturate synthesis and patenting activities historically.
Implications for R&D and Investment
- The patent's broad claims reflect a strategic effort to capture a wide chemical space, influencing subsequent derivative development.
- Its expiration enables freedom-to-operate for companies developing novel sedative or hypnotic agents based on similar structures.
- Insights from the patent can inform novel modifications aiming for improved safety or reduced side effects.
Conclusion
US Patent 3,169,424 claims a broad class of substituted phenyl barbiturates, with extensive claims covering chemical structures, synthesis methods, and therapeutic use. Its expiration opens opportunities for generic development and active research. Its structure and scope influence the landscape of sedative drug patenting, especially in the context of barbiturate derivatives prior to the rise of benzodiazepines.
Key Takeaways
- The patent’s broad chemical claims cover a large class of barbiturates, impacting patent strategies in the sedative space historically.
- It was filed during the height of barbiturate development, but it is now expired, removing enforceability.
- The structural scope guides both historical patenting activity and current research directions for new derivatives.
- It provides a foundational reference for designing safer or more effective sedatives within the classical barbiturate class.
- Recent patents tend to focus on non-barbiturate options due to safety concerns over the therapeutic window of barbiturates.
Frequently Asked Questions
1. Can a company develop a drug based on the structures claimed in US 3,169,424 today?
Yes, because the patent has expired, there are no enforceable rights, allowing freedom to develop and commercialize derivatives within the scope.
2. Does the broad chemical scope of this patent cover all derivatives of the specified structure?
It covers a wide range but is limited to the specific substituted phenyl derivatives of the barbituric acid described in the claims.
3. Are there modern drugs directly derived from compounds in this patent?
Most modern sedatives have shifted away from barbiturates due to safety concerns, but some derivatives are still used in certain medical contexts.
4. How does this patent influence current research?
While expired, it informs medicinal chemists about chemical modifications available within this compound class and helps shape new derivative designs.
5. What should companies do to avoid infringement?
Since the patent is expired, no infringement issues exist regarding its claims. For new patents, focusing on novel modifications outside the scope of this patent's claims is recommended.
References
- US Patent 3,169,424, "Barbituric Acid Derivatives," granted 1965.
- U.S. Patent and Trademark Office records.
- "History of Barbiturates," DrugBank Database.
- Kelley, M., et al., "The Evolution of Sedative Drugs," Journal of Pharmaceutical Innovation, 2019.
