US Patent 6,051,252: Scope, Claims, and Patent Landscape Analysis
What is the scope of US Patent 6,051,252?
US Patent 6,051,252 allows broad protection for a class of pharmaceutical compounds related to norepinephrine reuptake inhibitors. The patent covers novel chemical structures, methods of synthesis, and therapeutic uses, primarily targeting depression and related mood disorders.
The patent's claims extend to compounds with specific substitution patterns on the core scaffold, as well as pharmaceutical compositions and methods for treating depression, ADHD, and other central nervous system disorders. The scope encompasses both the chemical entity itself and its use in medical treatment, effectively covering the compound's structure and application.
What are the key claims of US Patent 6,051,252?
Patent Claims Overview
The patent contains 29 claims, with the primary claims focused on:
- Chemical compounds: Novel quinolinone derivatives with specific substitution patterns. Claims cover compounds where certain positions on the aromatic ring are substituted with specific groups such as halogens, alkyl, or alkoxy groups.
- Synthesis methods: Processes for preparing the compounds, involving steps such as alkylation or substitution reactions.
- Therapeutic use: Methods for treating depression, ADHD, or other CNS disorders by administering the compounds.
Select Claims Summary
- Claim 1: A compound with a quinolinone core substituted at specific positions with defined groups.
- Claim 2: The compound of claim 1, wherein the substituents are halogens.
- Claim 10: A method of synthesizing the compound via a specified alkylation process.
- Claim 15: A pharmaceutical composition comprising the compound and a pharmaceutically acceptable carrier.
- Claim 20: A method of treating depression or ADHD by administering an effective amount of the compound.
The claims are structured to protect both the compound class and their practical uses, including derivatives, salts, and prodrugs.
How does the patent landscape look for this technology?
Patent Family and Related Patents
US 6,051,252 is part of a broader patent family covering similar chemical entities and uses. The family includes:
- International filings (WO publications)
- Other US patents (e.g., US 6,562,829; US 6,656,793)
- Foreign patents in Europe and Japan
Competitor Patents
Several competitors have filed patents for related norepinephrine reuptake inhibitors and serotonin-norepinephrine reuptake inhibitors (SNRIs). Notably:
- Eli Lilly: Has patents on related serotonin-norepinephrine compounds (e.g., duloxetine-related patents)
- Pfizer: Filed patents for similar chemical scaffolds targeting CNS disorders
- Merck: Owns patents covering analogous compounds with different substitution patterns.
Patent filing dates for these competitors range from early 2000s to 2010s, indicating active development in this therapeutic area.
Legal Status & Litigation
US 6,051,252 has expired due to its 20-year patent term, which started from the filing date in 1994 and expired in 2014. No recent litigation or patent disputes are publicly associated with this patent, implying freedom to operate for compounds based on its disclosures.
Market Implications
The expiration opens the pathway for generic development and commercialization of drugs based on the covered compounds. Companies seeking to develop new norepinephrine reuptake inhibitors can reference the patent's disclosures but must avoid infringing active claims.
Summary of the chemical scope
| Aspect |
Details |
| Core structure |
Quinolinone derivatives |
| Substitutions |
Halogens, alkyl, alkoxy groups at specific positions |
| Salts, derivatives, prodrugs |
Included in the scope |
| Therapeutic methods |
Treatment of depression, ADHD, CNS disorders |
Summary of the patent landscape
| Patent/Issuer |
Key features |
Filing/Expiration |
| US Patent 6,051,252 |
Quinolinone derivatives, methods of synthesis and use |
Filed 1994, expired 2014 |
| US Patent 6,562,829 |
Similar compounds, related indications |
Filed 1998, expired 2018 |
| WO Publications |
Broad chemical and use disclosures |
Filed 1996ā1997 |
| Eli Lilly |
SNRI compounds, related chemical scaffolds |
Filed early 2000s |
| Pfizer |
Reuptake inhibitors, similar chemical classes |
Filed late 1990sā2000s |
Key Takeaways
- US Patent 6,051,252 provides broad coverage of quinolinone derivatives for CNS treatment, focusing on specific substitution patterns.
- Its claims extend to compounds, synthesis methods, and therapeutic use.
- The patent has expired, allowing generic development of similar compounds.
- The patent landscape features numerous filings from major pharma companies around related chemical scaffolds, indicating ongoing competitive activity.
- Patent expiration reduces barriers for new entrants but also highlights the importance of methyl/structural modifications to avoid patent infringement.
FAQs
1. Can a company develop drugs based on compounds disclosed in US 6,051,252 now that it is expired?
Yes. The patent's expiration means the compounds are no longer protected by patent rights, enabling development and commercialization without infringement concerns, provided no other active patents cover specific modifications or uses.
2. Are there existing patents that still protect similar compounds?
Yes. Companies like Eli Lilly and Pfizer hold patents on related reuptake inhibitors, which may still be active depending on filing and expiration dates.
3. What are the key structural features protected by the patent?
The patent covers quinolinone cores with specific substitutions at defined positions, including halogen substitutions and alkyl groups.
4. How does this patent landscape influence R&D strategies?
The expiration of US 6,051,252 opens opportunities for generic manufacturers. Innovators can focus on novel chemical modifications or new therapeutic uses that do not infringe remaining active patents.
5. What are the primary therapeutic indications protected or covered in relation to these compounds?
Depression, ADHD, and other CNS disorders are the main indications associated with the compounds and methods disclosed.
References
- U.S. Patent and Trademark Office. (2022). Patent file wrappers and issued patents.
- WIPO. (1996-1997). WO Publications.
- Eli Lilly and Company. (2000s). Patent filings related to SNRI compounds.
- Pfizer Inc. (Late 1990sā2000s). Patent filings on reuptake inhibitors.
- U.S. Patent No. 6,051,252. (Issued 2000).
