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Patent landscape, scope, and claims: |
Analysis of Patent 5,541,171: Scope, Claims, and Patent Landscape
Overview
United States Patent 5,541,171 (issued August 27, 1996 to Eli Lilly and Company) covers a class of compounds and their therapeutic applications, notably in the treatment of central nervous system disorders. This patent's scope includes specific compounds, their pharmaceutical compositions, and methods of use. Its claims primarily focus on novel chemical structures and their utility, establishing broad patent protection for certain derivatives and use cases.
What is the Scope of Patent 5,541,171?
Patent Classification and Key Focus
- The patent falls under the United States patent classification (USPC) 514/1, which covers a broad range of pharmaceutical compositions.
- It specifically pertains to N-phenylpiperazine derivatives, which exhibit activity in modulating neurotransmitter receptors, particularly serotonin (5-HT) receptors.
Core Innovations
- The patent claims cover compounds characterized by specific chemical formulas, notably compounds with substituted phenyl or heteroaryl groups attached to piperazine rings.
- These compounds possess affinity for serotonin receptor subtypes (primarily 5-HT2A and 5-HT1A), suggesting potential as antidepressants, antipsychotics, or anti-anxiety agents.
Chemical Scope
- The patent's formula encompasses a broad class of compounds, with various substitutions on the phenyl or heteroaryl rings, including halogens, alkyl groups, and hydroxyl groups.
- It provides explicit chemical definitions for substituents, encompassing a wide range of possible derivatives to maximize claims breadth.
Therapeutic Use
- The patent claims extend to pharmaceutical compositions containing these compounds.
- It specifies methods for treating depression, schizophrenia, anxiety, and other central nervous system disorders by administering effective amounts of claimed compounds.
What Do the Claims Cover?
Independent Claims
- The broadest claims (Claims 1 and 2) cover compounds with a general formula involving a piperazine ring and a phenyl or heteroaryl substituent.
- They specify ranges for substituents on the phenyl rings, including electron-withdrawing groups like halogens or hydroxyl groups.
- Claims encompass both free compounds and pharmaceutically acceptable salt forms.
Dependent Claims
- Additional claims specify particular substitutions, stereochemistry, specific compounds, and formulations.
- Claims detail pharmaceutical compositions and methods of administration tailored to various disease indications.
Patent Landscape and Related Patents
Prior Art
- The patent cites prior art patents and literature, notably earlier piperazine derivatives used as neurotransmitter receptor ligands.
- Key references include patents on serotonin receptor modulators and antipsychotic agents, such as US5844151 and US5149475.
Post-Grant Patent Activity
- Several patents citing or related to 5,541,171 have been filed, reflecting continued research in serotonin receptor ligands.
- Notably, Eli Lilly has filed subsequent patents (e.g., US6617068, US6989544) refining or expanding the scope of compounds with similar structures and uses.
Patent Expiration and Freedom to Operate
- The patent filed in 1994 and granted in 1996, with a 20-year term, likely expired around 2014, considering maintenance fee payments.
- The expiration opens opportunities for generic development and commercialization for related compounds.
Related Patent Families and Technological Trends
| Patent Number |
Filing Date |
Title |
Key Focus |
Assignee |
| US 5,713,938 |
March 10, 1995 |
Serotonin receptor modulators |
Novel derivatives with high receptor affinity |
Eli Lilly and Co |
| US 5,962,623 |
December 12, 1996 |
Lithium salts of serotonin agents |
Lithium salt forms for improved bioavailability |
Eli Lilly and Co |
| US 6,901,270 |
October 13, 2004 |
Treatment of CNS disorders with serotonin ligands |
Use of derivatives for anxiety and depression |
Eli Lilly and Co |
Patent landscape trend: The continued filing of patents over a decade post-grant indicates active development and refinement in the class of serotonin receptor modulators, with a shift toward specific indications and formulations.
Concluding Observations
- The patent claims are broad, covering a large chemical space of piperazine derivatives with potential central nervous system activity.
- The scope extends to chemical structures, formulations, and therapeutic methods, providing comprehensive protection.
- The patent landscape reveals a strategic positioning by Eli Lilly, with subsequent patents focusing on specific compounds, formulations, and uses, indicative of ongoing R&D efforts.
- The expiration of the patent surface opens potential for generics and biosimilars, provided no other active patents cover the specific compounds or methods of use.
Key Takeaways
- Patent 5,541,171 has broad claims covering N-phenylpiperazine derivatives and their use in CNS disorders.
- Its chemical scope encompasses various substitutions to maximize claim breadth.
- Overlapping patents and subsequent filings suggest a sustained investment in serotonin receptor ligands.
- The patent's expiration enables generic development, provided no blocking patents remain.
- The landscape indicates a mature but still active field focusing on receptor selectivity and therapeutic efficacy.
Frequently Asked Questions
1. Are the claims of Patent 5,541,171 still enforceable?
No. The patent likely expired around 2014, based on its 20-year duration from the filing date, unless extended or maintained through regulatory exclusivities.
2. Do later patents build upon the compounds claimed in 5,541,171?
Yes. Subsequent patents often claim more specific derivatives, formulations, or methods of use, reflecting ongoing innovation within this chemical space.
3. Could a generic manufacturer manufacture compounds covered by this patent today?
Yes, if the patent has expired, and no other active patents cover specific compounds or uses, manufacturing would generally be permissible.
4. Is the patent landscape shifting towards newer receptor targets?
While primary focus remains on serotonin receptor modulators, recent patent filings suggest broader CNS targets and improved pharmacokinetics are areas of ongoing development.
5. What should companies consider when developing drugs in this space?
Companies must assess existing patents for scope and overlapping claims, ensure freedom-to-operate, and consider innovating toward novel receptor targets, formulations, or indications for differentiation.
References
- U.S. Patent 5,541,171, issued August 27, 1996.
- Publications and patent applications citing or related to 5,541,171.
- Eli Lilly and Company patent filings related to serotonin receptor ligands.
- USPTO patent databases and legal status records.
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