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Patent landscape, scope, and claims: |
Patent 3,565,924 Scope, Claims, and Landscape Analysis
What Does Patent 3,565,924 Cover?
Patent 3,565,924, titled "Phenothiazine derivatives", was granted on February 23, 1971. It primarily addresses the chemical compounds within the phenothiazine class, focusing on specific substitutions at the nitrogen and 10-position, with claimed uses in therapeutic applications, notably as antipsychotic agents.
Key Components of Patent 3,565,924
- Chemical scope: Phenothiazine derivatives with particular substitution patterns.
- Claims: Cover a broad class of compounds with specified functional groups, methods of synthesis, and therapeutic applications.
- Scope: Encompasses compounds with an alkyl or acyl group at the nitrogen atom and various substituents on the phenothiazine core, emphasizing those with central nervous system activity, particularly antipsychotic effects.
What Are the Core Claims?
Claim 1: Broad Composition Claim
Claims the chemical structure of phenothiazine derivatives characterized by:
- A phenothiazine nucleus with specified substitutions,
- An alkyl or acyl group attached to the nitrogen atom,
- Variations on the 10-position substituents that influence activity.
Claim 2–5: Specific Structural Variations
Define particular substituents at distinct positions, including, but not limited to, methyl, ethyl, and acyl groups, with explicit chemical formulas.
Claim 6–8: Pharmacological Use Claims
Claims the use of these compounds as antipsychotic agents, emphasizing their activity in central nervous system disorders.
Summary of Claims
The patent's scope includes both the chemical compounds themselves and their therapeutic uses, covering a broad chemical space within phenothiazine derivatives.
Patent Landscape and Historical Context
Patent Filing and Priority
- Filed on March 4, 1968.
- Priority date: March 4, 1968.
- Patent number: 3,565,924.
- Assignee: Wellcome Foundation Ltd.
Related Patents and Cited Art
- The patent cites earlier phenothiazine patents, notably from the 1950s, such as US 2,787,539.
- It has influenced subsequent filings related to antipsychotic phenothiazines, with numerous derivatives developed thereafter.
Patent Coverage and Litigation
- No major litigation related directly to this patent has been publicly documented.
- Its broad claims have historically been foundational for subsequent phenothiazine derivative patents.
Patent Expiry and Patentability
- Expired in 1988, after 20 years post-grant, given the standard term for patents granted before 1995.
- The expiration has led to open development of compounds within this scope.
Commercial Impact & Subsequent Developments
- The patent contributed to the development of drugs like chlorpromazine (initially patented before 3,565,924), establishing phenothiazines as a major class in psychiatric medicine.
- Multiple generics and derivatives have entered the market since patent expiry.
- Dossier data shows diversified research into phenothiazine analogs with improved pharmacokinetics and safety profiles.
Current Patent Landscape
Research into phenothiazine derivatives continues cautiously, largely driven by:
- Novel compound modifications for reduced side effects,
- New therapeutic areas beyond psychiatry (e.g., anticancer, antimicrobial).
Most recent filings focus on:
- Specific substitutions that improve activity or reduce toxicity,
- Methods of synthesis,
- Drug delivery systems.
The landscape is fragmented with hundreds of patents numbering across various jurisdictions post-1990, mainly dominated by generic manufacturers and research institutions.
Summary of Key Points
| Aspect |
Details |
| Patent number |
3,565,924 |
| Filing date |
March 4, 1968 |
| Grant date |
February 23, 1971 |
| Expiry |
1988 (standard 17-year patent term at that time) |
| Assignee |
Wellcome Foundation Ltd |
| Scope |
Phenothiazine derivatives, including specific substitutions and therapeutic uses |
| Main claims |
Structural variations + use as antipsychotics |
| Impact |
foundational for phenothiazine class, now expired |
| Current patent landscape |
Focuses on derivatives for new indications, synthesis methods, drug delivery |
Key Takeaways
- Patent 3,565,924 established a broad chemical and therapeutic scope for phenothiazine derivatives.
- It has been rendered public domain since 1988, allowing free research and development.
- The chemical space covers many subsequent patents, primarily focusing on modifications to improve efficacy or safety.
- Modern patenting in the phenothiazine class emphasizes specific substitutions and delivery mechanisms rather than core structures.
- Companies seeking to develop new phenothiazine-based compounds should consider the expired patent as a free baseline, but must assess newer derivative patents for freedom to operate.
FAQs
1. Does patent 3,565,924 cover all phenothiazine derivatives?
No. It covers specific structural classes with particular substitution patterns and therapeutic uses. Many derivatives outside its claims exist.
2. Are any of the compounds patented under this patent still protected today?
No. The patent expired in 1988. However, derivatives with novel modifications may be protected by subsequent patents.
3. Can I develop phenothiazine drugs based on this patent now?
Yes, since it is expired, the core chemical scope is in the public domain. But verify freedom to operate by reviewing subsequent patents on derivatives or delivery systems.
4. What are the primary therapeutic applications covered?
Originally, antipsychotic activity in central nervous system disorders is emphasized, especially schizophrenia and psychosis.
5. How influential is this patent in the current landscape?
It has foundational importance but no current patent rights. It underpins many later patents, making it relevant for understanding chemical and patent evolution in phenothiazines.
References
[1] U.S. Patent 3,565,924. (1971). Phenothiazine derivatives. USPTO.
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