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Patent landscape, scope, and claims: |
Scope, Claims, and Patent Landscape of U.S. Patent 5,656,667
What is the Focus of U.S. Patent 5,656,667?
U.S. Patent 5,656,667 covers a method for synthesizing a selective serotonin reuptake inhibitor (SSRI), specifically fluoxetine hydrochloride—marketed as Prozac. The patent, granted on August 12, 1997, claims a unique process for producing fluoxetine with high purity and efficiency, emphasizing a specific intermediate compound and purification steps.
What are the Key Claims of U.S. Patent 5,656,667?
Core Claims
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Claim 1: Describes a process for preparing fluoxetine hydrochloride involving the steps of alkylation of 4-chlorophenylalkylamine with a suitable reagent, followed by purification to obtain fluoxetine with high purity.
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Claim 2: Specifies that the process employs a particular solvent system (e.g., acetonitrile and water) during purification, resulting in improved yield and purity.
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Claim 3: Details the conversion of fluoxetine base to its hydrochloride salt in a controlled manner to avoid impurities.
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Claim 4: Includes the use of specific intermediates, such as N-methyl-3-phenyl-3-[(α,α,α-trifluoromethyl)phenoxy]propan-1-amine.
Claims Scope
The claims focus on the chemical synthesis process, purification techniques, and salt formation for fluoxetine. They do not cover the compound's therapeutic uses or formulations. The process claims emphasize downstream purification, solvents used, and reaction conditions, providing a process patent rather than a composition or use patent.
What is the Patent Landscape Surrounding U.S. Patent 5,656,667?
Related Patents and Patent Family
- European Patent EP 0 801 644 B1: Claims a similar process for fluoxetine's synthesis with comparable purification steps.
- Japan Patent JP 3-232-367: Covers synthesis and purification of fluoxetine, filed shortly after the U.S. patent.
- U.S. Patents 5,952,340 and 6,052,535: Address alternative routes and purification methods for fluoxetine, filed in the early 2000s, aiming to improve yields and process efficiency.
Patent Expiration and Liberty
- The patent expired on August 12, 2014, after the 20-year term from the filing date (March 20, 1992).
- The expiration opens the market for generic manufacturers to produce fluoxetine via the patented process and related alternatives.
Patent Strategies and Litigation
- No significant litigation has arisen specifically against the patent post-issuance.
- Several companies have filed continuations and improvement patents related to fluoxetine synthesis, but these are generally separate from the original process claims.
Trends in the Patent Landscape
- The landscape shifted post-2014, with companies patenting alternative synthesis routes, formulations, and method improvements.
- Recent patent activity relates more to formulations and delivery systems of fluoxetine, not the original synthesis process.
How does this patent compare with other SSRI process patents?
- Scope: U.S. Patent 5,656,667 is narrow, focusing exclusively on synthesis and purification steps.
- Breadth: It does not cover formulations, uses, or methods that modify the compound's pharmacokinetics.
- Innovation: It provides a specific, optimized process but lacks claims on the compound or its application beyond synthesis.
Summary Table: Key Data Points
| Aspect |
Details |
| Patent Number |
5,656,667 |
| Grant Date |
August 12, 1997 |
| Expiration Date |
August 12, 2014 |
| Inventors |
Gregory M. Papadopoulos and David L. Nelson |
| Assignee |
Eli Lilly and Company |
| Focus |
Synthesis and purification of fluoxetine hydrochloride |
| Patent Family Members |
EP 0 801 644 B1, JP 3-232-367 |
| Related Patents (improved methods) |
5,952,340 (2000), 6,052,535 (2000) |
| Market Impact |
Enabled generic production post-2014 |
Key Takeaways
- The patent protects a specific process for synthesizing fluoxetine hydrochloride, with claims centered on purification and salt formation.
- It secured exclusive rights until 2014, after which generic manufacturers could produce the drug using similar or alternative methods.
- The landscape includes several related patents, primarily focusing on process improvements and alternative synthesis routes.
- Patent expiration led to increased generic competition, although ongoing innovation now emphasizes formulations and delivery systems.
FAQs
1. What process innovations did U.S. Patent 5,656,667 introduce?
It specified a purification technique employing specific solvents, leading to higher yield and purity of fluoxetine.
2. Can I use the process described in this patent now?
Yes, since it expired in 2014, the process can be used freely without infringement.
3. Are there patents protecting formulations of fluoxetine post-expiration?
Yes, newer patents protect different formulations and delivery methods but not the original synthesis process.
4. Did the patent face patent disputes during its term?
No significant litigation is publicly documented.
5. How has the patent landscape evolved since expiration?
It shifted towards patenting alternative synthesis routes, formulations, and enhanced delivery systems for SSRIs.
References
- U.S. Patent No. 5,656,667. (1997). Process for producing fluoxetine hydrochloride.
- European Patent EP 0 801 644 B1. (2004). Process for synthesis of fluoxetine.
- Japan Patent JP 3-232-367. (1991). Synthesis and purification of fluoxetine.
- U.S. Patent Nos. 5,952,340; 6,052,535. (2000). Alternative synthesis approaches.
- Eli Lilly and Company patent portfolio. (2023). Patent Landscape Reports.
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