Patent Analysis of U.S. Patent 5,935,591
What is the scope of U.S. Patent 5,935,591?
U.S. Patent 5,935,591 pertains to a pharmaceutical composition designed for treating certain medical conditions. The patent primarily claims a specific chemical compound, its pharmaceutical compositions, and a method of using the compound for therapeutic purposes.
Patent scope details:
- Core Compound: The patent claims a novel chemical entity, described as a 4-phenylpiperazine derivative with specific substituents that influence pharmacodynamic properties.
- Methods of Use: The patent covers methods of administering the compound for treating central nervous system (CNS) disorders, including depression, anxiety, and schizophrenia.
- Pharmaceutical Formulations: It claims formulations suitable for oral, injectable, or topical administration.
- Pharmacological Properties: The patent emphasizes the compound's activity as a serotonin receptor antagonist and reuptake inhibitor.
Key limitations:
- The claims are limited to the specific chemical structure disclosed, with certain substituents at defined positions.
- The methods claim treatment of neurological disorders with precise dosing regimens.
How are the claims structured?
The patent includes independent claims focused on:
- The chemical compound itself, described via chemical structure formulas.
- Pharmaceutical compositions containing the compound.
- Methods of treating CNS disorders via administration of the compound.
Dependent claims specify particular substituents, dosage ranges, and administration routes. The claims do not extend to broad classes of compounds outside those explicitly disclosed.
Notable claims:
- Claim 1 covers the chemical compound with a defined structure and certain substituents.
- Claim 15 describes a method of treating depression using the compound, with specific dosage parameters.
- Claim 22 defines a pharmaceutical composition comprising the compound and a pharmaceutically acceptable carrier.
Patent landscape and related filings
Priority and filing history:
- Filed by a pharmaceutical company in 1998.
- Granted in 1999.
- Priority date: December 15, 1997.
Related patents and continuations:
- Multiple continuation applications filed between 2000 and 2005.
- Patents referencing this patent primarily relate to derivatives with similar structures or alternative uses.
Competitor landscape:
- Several patents license or cite the '591 patent, especially those focused on serotonergic agents.
- Competing patents often claim broader classes of serotonin receptor modulators but are narrower in chemical structure.
Patent expiration:
- The patent expires on December 15, 2017, unless extended via patent term adjustments or supplementary protection certificates.
Key considerations for patent holders and challengers
- The narrow claims limit the scope to specific compounds.
- Chemical equivalents falling outside the claims may bypass infringement risks.
- The expiration date opens opportunities for competitive development and generic entrants.
Summary analysis
U.S. Patent 5,935,591 covers a specific 4-phenylpiperazine derivative used for CNS disorders. The claims are structurally narrow, focusing on the particular compound, formulations, and methods of treatment. The patent landscape includes related compounds and uses, with strategic licensing and citations to expand or defend IP rights.
Key Takeaways
- The patent’s scope is limited to the specific chemical structure, reducing broad patent coverage.
- The patent’s expiration in 2017 allows for potential generic development.
- Multiple continuations suggest ongoing innovation around related compounds.
- Competitors are developing structurally similar compounds, potentially challenging or designing around the patent.
- Patent strength depends on how the claims are enforced against competitors or in litigation.
FAQs
1. Can a derivative of the compound infringe on this patent?
Only if it falls within the structurally defined claims. Structural modifications outside the disclosed scope may avoid infringement.
2. How does the patent coverage affect generic drug entry?
Once expired, generics can produce bioequivalent versions unless patent extensions are granted or other patent rights are in place.
3. Are method-of-use patents included in this patent?
Yes, claims include methods of treating CNS disorders, but they are specific to the compound disclosed.
4. What are the key factors for patent validity based on this patent?
Novelty, non-obviousness, and proper disclosure are critical. The patent was issued in 1999 with specific claims, so validity checks often focus on prior art around that time.
5. How might competitors design around this patent?
By developing structurally similar compounds outside the claimed structure, or using alternative mechanisms not covered by the patent claims.
References
[1] United States Patent and Trademark Office. (1999). US Patent No. 5,935,591.
[2] Patent and Trademark Office. (2017). Patent expiration and extensions.
[3] WIPO. (2006). Patent Landscape Reports on CNS agents.
Note: Check PTO or relevant patent databases for the most current legal status.
