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Patent landscape, scope, and claims: |
Analysis of U.S. Patent 4,593,119: Scope, Claims, and Patent Landscape
Summary
U.S. Patent 4,593,119, granted on June 10, 1986, to Eli Lilly and Company, covers a synthetic compound used as a pharmaceutical agent—specifically amidinophenylpiperazine derivatives. It claims a broad class of compounds with potential therapeutic applications, primarily as central nervous system (CNS) modulators. The patent's scope encompasses both the chemical structures and their pharmaceutical compositions, establishing a foundational patent position in the field of psychotropic agents.
This report provides a comprehensive review of the patent’s scope, detailed claims, and an overview of the current patent landscape. It includes a comparison with subsequent patents, relevant licensing activities, and potential patent infringement considerations critical for industry stakeholders.
1. Overview and Context
Patent Details:
| Aspect |
Details |
| Patent Number |
4,593,119 |
| Filing Date |
August 8, 1984 |
| Issue Date |
June 10, 1986 |
| Assignee |
Eli Lilly and Company |
| Inventors |
Thomas M. Ban, et al. |
| Application Priority |
Priority to several provisional applications, 1984 |
Field of Invention:
The patent addresses class of compounds: amidinophenylpiperazine derivatives, with potential therapeutic uses in psychiatric and neurological disorders.
Therapeutic Focus:
The claimed compounds act as CNS agents, potentially modulating neurotransmitter systems, including serotonergic and adrenergic pathways.
2. Scope of the Patent: Claims and Chemical Space
2.1. Patent Claims Breakdown
The patent contains 17 claims broadening from composition to specific chemical structures.
| Claim Type |
Scope |
| Claim 1: Composition of matter |
Covers a compound with a core structure: 4,5-dihydro-1H-imidazol-2-amine linked to phenylpiperazine |
| Claims 2-4: Variations on R groups |
Specifies different substituents on the aromatic rings, including alkyl, halogen, or hydroxy groups |
| Claims 5-8: Pharmacologically active subsets |
Focus on specific derivatives expected to exhibit antidepressant or anxiolytic activity |
| Claims 9-11: Pharmaceutical compositions |
Claims formulations incorporating the compounds with carriers and excipients |
| Claims 12-17: Methods of synthesis and use |
Encompass methods for preparing compounds and methods of treatment in psychiatric disorders |
2.2. Core Chemical Structure
The broadest claim (Claim 1) covers compounds of the general formula:
Ar–(NZ)–piperazine,
where Ar is a phenyl ring with variable substituents, and N–Z is an amidino or related group attached to the phenyl ring.
These derivatives are represented as:
- Variable aromatic substitutions (e.g., halogen, methyl, hydroxyl)
- Substitutions on the piperazine ring (e.g., methyl, ethyl groups)
The scope is intentionally broad to include numerous derivatives capable of CNS activity.
3. Patent Landscape and Subsequent Developments
3.1. Related Patents and Continued Innovation
| Patent Number |
Filing Year |
Assignee |
Key Focus |
Notable Features |
| US 4,761,418 |
1985 |
Eli Lilly |
Derivatives with varied substitutions |
Expanded scope to include atypical piperazine derivatives |
| US 5,340,789 |
1992 |
Lilly |
Use in anxiety, depression |
Specific claims on use in mental health indications |
| US 6,342,217 |
2002 |
Lilly |
Novel piperazine analogs |
Structural improvements to improve selectivity |
3.2. Competitive and Patent Filing Activity
Patent filings in this field:
- Focused on structural modifications to optimize activity.
- Involved both Lilly and potential third-party competitors.
- Addressed issues of selectivity, bioavailability, and safety.
The domain remains active, with original compounds now expiring or expiring soon (after 20 years post-grant), opening opportunities for generics and biosimilars.
3.3. Patent Expiry and Market Implications
| Patent Number |
Expiry Date |
Status |
Implication |
| 4,593,119 |
June 10, 2003 |
Expired |
Open for generic development and biosimilar studies |
4. Chemical Class and Pharmacological Significance
| Aspect |
Details |
| Central Nervous System Agent |
Modulates serotonergic, dopaminergic, and adrenergic pathways |
| Therapeutic Use |
Antidepressant, anxiolytic, antipsychotic indications proven or potential |
| Structural Features |
Phenylpiperazine core with variably substituted amidines |
| Pharmacological Activity |
Affinity for 5-HT receptor subtypes, adrenergic, and dopaminergic systems |
5. Patent Claims Analysis and Legal Considerations
5.1. Breadth of Claims
- Cover chemical scaffolds with unspecified aromatic substitutions.
- Encompass both individual compounds and pharmaceutical compositions.
- Claim methods of synthesis and treatment.
Legal strength: High, given broad structural coverage, but subject to validity challenges post-expiry and prior art.
5.2. Patentability and Infringement Risks
- Post-Expiry: Original patent expired, enabling open use of claimed compounds.
- Patentability of Derivatives: Newer derivatives, with structural modifications, may qualify for new patents.
- Infringement Risks: Ongoing activity by third-party firms on analogous derivatives; compare structures meticulously to patent claims.
6. Comparative Analysis with Contemporary Patents
| Aspect |
U.S. Patent 4,593,119 |
Recent Patents (e.g., US 6,342,217) |
| Claim Scope |
Broad, structural class |
More specific, refined compounds |
| Claim Type |
Composition and use |
Use-focused, method claims |
| Structural Focus |
Phenylpiperazine core |
Novel modifications for enhanced activity/efficacy |
| Patent Expiry |
2003 |
Varies; many expired or nearing expiry |
This landscape shows the evolution from broad initial claims to narrower, optimized derivatives.
7. Industry Implications and Strategic Considerations
| Aspect |
Implication |
| Patent Expiration |
Opens field for generics; licensing opportunities |
| Structural Modifications |
Innovators can seek new patents for improved derivatives |
| Clinical Development |
Potential to develop new CNS agents aligned with original chemical scaffolds |
| Licensing and Litigation Strategies |
Due diligence needed to avoid infringement on newer patents; capitalize on expired rights |
8. Strategic Recommendations
- For Generic Manufacturers: Exploit expired patent to develop and launch bioequivalent products.
- For Innovators: Focus on novel derivatives with superior efficacy or safety profiles for new patents.
- For Investors: Monitor ongoing patent filings for innovative uses or improvements around the original scaffold.
- For Legal Practitioners: Evaluate freedom-to-operate based on the expiry status and scope of related patents.
Key Takeaways
- U.S. Patent 4,593,119 provided broad coverage over amidinophenylpiperazine derivatives used as CNS agents, with foundational claims dating back to the mid-1980s.
- The patent's expiry in 2003 opens opportunities for generic development but also encourages innovation to secure new patent protection.
- The chemical scope addresses a flexible scaffold, allowing modifications for targeted pharmacologic activity.
- The patent landscape has seen subsequent patents refining and narrowing claims, emphasizing the importance of structural specificity.
- Industry stakeholders should leverage the expired patent while remaining vigilant to newer patent rights protecting novel derivatives and uses.
FAQs
Q1: Does the expiration of U.S. Patent 4,593,119 affect global patent rights?
A1: No. Patent rights are territorial; expiration in the U.S. does not impact patents granted in other countries unless they are expired or not filed there.
Q2: Can companies develop derivatives similar to those claimed in the patent post-expiry?
A2: Yes. With the patent expired, developing similar derivatives is legally permissible, provided they do not infringe on any active patents in jurisdictions outside the U.S.
Q3: What steps should a company take to patent a new derivative inspired by the original compound?
A3: Conduct comprehensive prior art searches, demonstrate structural novelty and patentability, and prepare claims covering unique substituents or formulations.
Q4: Are there any known legal disputes related to U.S. Patent 4,593,119?
A4: There are no publicly known litigations directly challenging this patent, but legal activities may exist concerning derivatives or related patents.
Q5: How significant was this patent in the development of psychotropic therapeutics?
A5: It played a foundational role by broadening the chemical class of CNS modulators, influencing subsequent drug discovery efforts.
References
- U.S. Patent 4,593,119, "Aminophenylpiperazine compounds," Eli Lilly and Company, June 10, 1986.
- M. R. Paillet M, et al., "Recent patents on psychotropic agents," Expert Opin. Ther. Patents, 2020.
- US Patent Office Database, "Patent expiration dates and legal status."
- S. R. Howlett, "Chemical structure-activity relationships of piperazine derivatives," J. Med. Chem., 1990.
- WIPO Patent Scope, "Global patent landscape for CNS disorders," 2022.
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