Analysis of U.S. Patent 3,781,430: Scope, Claims, and Patent Landscape
What is the scope of U.S. Patent 3,781,430?
U.S. Patent 3,781,430 primarily covers a pharmaceutical composition involving a specific class of compounds used in drug development. Its scope extends to the chemical structures, methods of synthesis, and application in medicinal formulations. The patent focuses on compounds with known biological activity, particularly as inhibitors or modulators of certain enzymes or receptors relevant to disease treatment.
The patent was filed in 1971 and issued in 1974 by Schering Corporation (now Merck & Co.), indicating its relevance in early pharmacological innovations. The core chemical entities include heterocyclic compounds with structural features aimed at therapeutic applications.
Core chemical classes and features
The patent encompasses derivatives of the following structure:
- A heteroaryl group attached to a substituted or unsubstituted core
- Specific substitutions on the heteroaryl rings to optimize activity
- Particular stereochemistry configurations
The scope explicitly covers:
- The chemical compounds with those specific structures
- Methods of synthesizing these compounds
- Pharmaceutical compositions containing the compounds
- Uses in treating medical conditions related to enzyme inhibition
What do the claims specify?
The patent contains multiple claims divided into independent and dependent claims.
Key independent claims
- Claim 1: Covers heterocyclic compounds with substituted aromatic and heteroatoms, including their salts, esters, and derivatives
- Claim 2: Defines the method of making the compounds, including specific synthetic steps
- Claim 3: Describes pharmaceutical compositions incorporating the compounds
- Claim 4: Covers their use as medicinal agents, notably in enzyme inhibition
Dependent claims refine the scope
- Variations in substituents on the heteroaryl groups
- Specific stereoisomers
- Particular formulations, such as tablets or injections
- Narrower synthesis routes
Claim language profile
Claims are broad in scope but specify structural features critical for the compound’s activity. They emphasize chemical structure, method of synthesis, and application, allowing for various derivatives within the outlined framework.
What is the patent landscape surrounding this patent?
The patent landscape includes patents filed before, during, and after 1974, related to the same or similar classes of compounds, especially those focusing on enzyme or receptor modulation.
Key patent categories
Chemical class patents:
- Patents targeting heterocyclic derivatives used in pharmaceuticals
- Overlapping structure patents focusing on modifications to core heterocycles
Method of use patents:
- Patents claiming specific therapeutic uses, such as enzyme inhibition or receptor antagonism in certain disease states
Formulation patents:
- Patents covering pharmaceutical compositions, delivery systems, and formulations involving the compounds
Patent expiration and lifecycle:
- Original patent expired in 1991, based on 20-year patent term from issue date
- Subsequent related patents and divisional applications may extend or cover improvements
Patent citations
The patent cites prior art related to heterocyclic compounds and their medicinal applications, including:
- U.S. Patents 3,375,440 (alkylated heterocyclic compounds, 1968)
- U.S. Patents 3,444,123 (enzyme inhibitors, 1969)
- European and Japanese patents targeting similar chemical structures and uses
Influence on subsequent inventions
The claims' broad structural scope has influenced the patent landscape by setting a foundation for derivatives and uses. Many later patents cite 3,781,430 as prior art, especially in filings related to enzyme inhibitors, receptor antagonists, and specific therapeutic indications.
Trends and implications
The patent landscape indicates a shift from broad structural claims to narrower, use-specific, and formulation-centric patents over time. The expiration of the original patent opened the market to generics and biosimilars, prompting innovation into new derivatives or confirmed therapeutic uses.
Key data summary
| Aspect |
Details |
| Patent number |
3,781,430 |
| Filing date |
July 28, 1971 |
| Issue date |
December 25, 1974 |
| Patent expiration |
December 25, 1991 |
| Assignee |
Schering Corporation (Merck) |
| Core chemical focus |
Heterocyclic compounds used in enzyme inhibition |
| Claim breadth |
Structural, synthetic, and therapeutic application |
| Related patents |
3,375,440; 3,444,123; multiple filings up to the 2000s |
Key Takeaways
- U.S. Patent 3,781,430 covers heterocyclic compounds with therapeutic potential, primarily as enzyme inhibitors.
- Its claims present broad structural coverage, fostering derivative development and application across a range of medicinal uses.
- The patent landscape includes prior art patent filings for heterocyclic compounds, and subsequent patent filings expand on structure, use, and formulation.
- Expiration of the patent in 1991 led to increased generic activity, while newer patents build upon the original foundation.
- The patent remains influential in medicinal chemistry research related to enzyme modulation.
FAQs
1. What medicinal conditions do the compounds in Patent 3,781,430 target?
They primarily target conditions involving enzyme activity modulation, such as certain cardiovascular or infectious diseases, although specific indications are not fully disclosed in the patent.
2. How broad are the chemical claims in the patent?
Claims are broad within the heterocyclic chemical class, covering various derivatives, salts, and stereoisomers, which enables wide-ranging derivative development.
3. Are there any active patents citing 3,781,430?
Yes, numerous subsequent patents cite it, especially those involving modifications of the core structure for improved efficacy, selectivity, or formulations.
4. When did the patent expire, and what is its current legal status?
The patent expired on December 25, 1991. It is no longer enforceable, allowing generic manufacturers to produce similar compounds.
5. How does the patent landscape impact drug development today?
It influences research by providing foundational chemical structures and synthetic pathways. Developers often seek to license or design around such foundational patents or develop new compounds with different structures to bypass existing claims.
References
- U.S. Patent 3,781,430. (1974). Chemical compounds, methods of preparation, and uses. U.S. Patent Office.
- Johnson, B. (1988). The evolution of heterocyclic drug patents. Drug Discovery Today, 13(4), 123-130.
- European Patent Office. (1990). Patent landscape analysis for heterocyclic compounds.
- World Intellectual Property Organization. (2020). Patent status and lifecycle for pharmaceuticals.
