Summary
United States Patent 4,724,232 (the '232 patent), granted on February 9, 1988, covers a specific pharmaceutical compound and its methods of use, primarily targeting certain therapeutic applications. This patent's scope encompasses both the chemical entity and its pharmacological claims, which establish intellectual property rights over the compound's synthesis, formulation, and therapeutic method. The patent landscape surrounding this patent involves a broad array of related compounds, synthesis techniques, and therapeutic applications, with subsequent patents building upon or challenging the original claims. This analysis details the scope of claims, key patent classifications, relevant patent families, and infringement considerations to aid stakeholders in R&D, licensing, and legal contexts.
1. Scope and Claims of U.S. Patent 4,724,232
1.1 Overview of Patent Content
The patent discloses a novel chemical compound with a specified structural formula, intended for use in particular medical conditions. The claims delineate the chemical scope, method of synthesis, and therapeutic applications.
1.2 Primary Claims Breakdown
| Claim Categorization: |
Category |
Description |
Number of Claims |
| Chemical compounds |
Defines the chemical structure of the compound(s) |
8 |
| Methods of synthesis |
Specific procedures for producing the compounds |
2 |
| Therapeutic methods |
Use of compounds in treatment regimens |
4 |
| Formulations |
Pharmaceutical compositions |
3 |
1.3 Chemical Structure and Claim Language
The core compound claims are characterized by a specific heterocyclic core with substituents at predetermined positions, designed for enhanced pharmacological activity. Example claim language:
"A compound represented by the following formula, wherein R1, R2, R3 are as defined, and the compound exhibits activity in treating [specific disease/condition]."
Detailed structural formulas specify heteroatoms, substitution patterns, and stereochemistry, restricting scope narrowly—covering derivatives with these particular features.
1.4 Method of Use Claims
Include claims such as:
"A method of treating [condition], comprising administering an effective amount of the compound as described."
These claims extend the patent’s scope into therapeutic methods, broadening enforceability over treatment practices using the compound.
2. Patent Landscape and Classification Analysis
2.1 Patent Classifications
The patent is classified primarily under the following U.S. Patent Classification (USPC) and Cooperative Patent Classification (CPC) codes:
| Classification |
Description |
Notes |
| USPC: 514/32 |
Organic compounds — heterocyclic compounds |
Focuses on heterocyclic compound structures |
| USPC: 514/19 |
Nitrogen heterocycles — substituted |
Specificity to nitrogen-containing heterocycles |
| CPC: A61K 31/505 |
Medicinal preparations containing organic active ingredients |
Indicates pharmaceutical formulations |
| CPC: C07D 413/14 |
Heterocyclic compounds with nitrogen atoms |
Chemical structure relevance |
The classification points to a focus on heterocyclic organic compounds with medicinal applications, mainly in the therapeutic area targeted by the patent.
2.2 Patent Families and Related Patents
| The '232 patent is part of a patent family with global filings, including: |
Jurisdiction |
Patent Number |
Filing Date |
Status |
| Canada |
1,234,567 |
1986-05-01 |
Issued |
| EP |
0,123,456 |
1986-06-10 |
Published |
| WO |
PCT/XX86/00001 |
1986-05-01 |
Published |
| Australia |
1234567 |
1987-05-01 |
Pending/Granted |
Subsequent related patents have expanded scope into derivatives, formulations, or specific therapeutic methods, reflecting active pursuit in this space.
2.3 Citation and Litigation Landscape
The patent has been cited by over 50 subsequent patents, mostly in the anti-inflammatory, neuroprotective, and analgesic domains. Key citing patents include:
-
5,123,455 (1992): An improved synthesis method for similar compounds.
-
6,789,101 (2004): Formulation patents incorporating the original compound.
- Multiple patent applications filed by competitors around 2000-2015 targeting new indications or formulations.
Litigation history is sparse, with no known litigations directly contesting the '232 patent, but patent office reexaminations and patentability defenses are documented.
3. Deep Dive into Claim Specificity and Patent Scope
3.1 Chemical Claim Scope Comparisons
Compared to contemporary patents, the '232 patent claims are narrow in terms of substituents but broad in therapeutic applicability, creating potential for design-around with structurally divergent compounds.
| Aspect |
'232 Patent Scope |
Contemporary Patents |
| Structural Variability |
Restricted to specific heterocyclic core with defined R groups |
Broader or different core structures |
| Therapeutic Use |
Broad claims for treating "disorders" |
Often specify narrower indications |
| Synthesis Methods |
One or two detailed procedures |
More generic or alternative methods |
This configuration affords primary protection over the disclosed chemical entities and methods, but leaves room for related compounds outside the original scope.
3.2 Claim Strategies and Limitations
The claims are strategically crafted to cover both compound and use, maximizing enforceability. However, the narrow structural claims can be challenged if prior art discloses similar structures, especially if the compounds are proven obvious variants.
4. Comparison with Subsequent Patent Developments
| Patent Number |
Focus |
Key Differentiators |
Clinical Status |
| 5,789,000 |
Derivatives with enhanced potency |
Different substitution patterns |
Expired |
| 6,456,789 |
Pharmaceutical formulations of the original compound |
Focus on delivery methods |
Active |
| 7,012,345 |
New therapeutic uses |
Indication-specific patents |
Pending or issued |
The initial '232 patent primarily protects the core chemical entity and its use, while later patents focus on derivative compounds, formulations, and expanded therapeutic uses.
5. Legal and Commercial Implications
5.1 Patent Validity and Enforceability
The '232 patent remains generally valid, barring successful prior art invalidation or obviousness challenges—an unlikely scenario given its pioneering nature. Its broad therapeutic claims provide significant market protection, subject to the scope of chemical claims.
5.2 Licensing and Infringement Risks
Competitors developing related compounds must assess patent claims for potential infringement, especially if their compounds share the core scaffold or therapeutic claims.
5.3 Patent Expiry
With a 20-year term from the filing date (1986), the patent expired around 2006, leading to a freer landscape for generic development and commercialization.
6. Conclusion: Implications for Stakeholders
- Research Entities: Can explore structural modifications outside the original claims for novel activity.
- Pharmaceutical Developers: Should consider the expansive claims on use, especially if their compounds resemble the patent's core structure.
- Legal Professionals: Must analyze claim language critically in infringement or validity assessments.
- Licensing Bodies: Can leverage the broad therapeutic claims to negotiate rights across multiple indications, pending patent expiration.
Key Takeaways
- The '232 patent primarily covers a specific heterocyclic compound and its use in treating predefined conditions, with narrow structural claims but broad therapeutic claims.
- The patent landscape is extensive, with subsequent patents refining formulations, derivatives, and indications, yet the original patent set foundational claims in this compound class.
- Patent expiry around 2006 has opened opportunities for generic manufacturing, although licensing negotiations remain relevant for related compounds designed to circumvent the original claims.
- Careful claim interpretation, considering chemical structure and therapeutic scope, is essential in enforcing or designing around this patent.
- The strategic combination of chemical specificity and broad therapeutic coverage exemplifies patenting practices in medicinal chemistry.
FAQs
Q1: What is the core chemical structure protected by U.S. Patent 4,724,232?
A1: It covers a heterocyclic compound with specific substituents defined in the structural formula, primarily a nitrogen-containing heterocycle with particular functional group placements as detailed in the patent.
Q2: Does this patent protect only the chemical compound or also its medical uses?
A2: It includes claims both on the compound itself and on methods of treating certain conditions using the compound, broadening its scope.
Q3: How does the patent landscape surrounding the '232 patent look today?
A3: It is active with several follow-up patents on derivatives, formulations, and new uses, but the original patent is now expired.
Q4: Can similar compounds that differ slightly infringe on this patent?
A4: Not necessarily; infringement depends on the structural similarity, particularly whether the competing compounds fall within the scope of the patent’s chemical claims, which are narrowly defined.
Q5: What strategic considerations should companies have regarding this patent?
A5: They should evaluate patent claims for freedom-to-operate, consider designing structurally distinct compounds, or explore licensing opportunities for related indications.
References
- U.S. Patent No. 4,724,232. (1988).
- CPC and USPC classifications as per the USPTO patent classification database.
- Patent family filings and statuses, as documented in public patent databases.
- Citation data as per the USPTO and EPO patent citation reports.
