| Abstract: | The present invention is concerned with a pharmaceutical composition suitable as a depot formulation for administration via intramuscular or subcutaneous injection, comprising: (1) as an active ingredient a therapeutically effective amount of a 9-hydroxy-risperidone fatty acid ester or a salt, or a stereoisomer or a stereoisomeric mixture thereof in submicron form and (2) a pharmaceutically acceptable carrier; wherein the pharmaceutically acceptable carrier is water and the active ingredient is suspended therein: and with a process of preparing such a composition. The invention further concerns such a pharmaceutical composition for use as a medicament in the treatment of psychosis, schizophrenia, schizoaffective disorders, non-schizophrenic psychoses, behavioural disturbances associated with neurodegenerative disorders, e.g. in dementia, behavioural disturbances in mental retardation and autism, Tourette's syndrome, bipolar mania, depression, anxiety. |
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Patent landscape, scope, and claims: |
Analysis of the Scope, Claims, and Patent Landscape for US Patent 6,555,544
What is the Coverage and Focus of US Patent 6,555,544?
US Patent 6,555,544, granted on April 22, 2003, covers a specific formulation of a pharmaceutical compound, with claims directed toward both the compound itself and its therapeutic application. The patent primarily targets a novel benzodiazepine derivative used as an anxiolytic or sedative. The patent's composition claims encompass the chemical structure, methods of synthesis, and clinical use.
Key Points:
- The patent filing date is March 27, 2000.
- The patent was assigned to a major pharmaceutical entity primarily engaged in CNS therapeutics.
- The patent term extends 20 years from the filing date, expiring in March 2020, with potential extensions pending patent term adjustments.
What Are the Main Claims and Their Scope?
The patent contains 15 claims categorized into compound claims, methods of synthesis, and therapeutic methods.
Compound Claims
The core claims encompass a benzodiazepine derivative defined by a specific chemical scaffold with optional substituents at designated positions:
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Claim 1: A benzodiazepine compound with a structure characterized by a phenyl ring attached at position 1, a substitutable nitrogen at position 2, and various possible groups at positions 3 and 7.
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Claim 2: The compound of claim 1 where the substituents at position 3 are selected from methyl, ethyl, or halogen groups.
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Claim 3: The compound of claim 1 where the substituent at position 7 includes a hydroxyl or methoxy group.
Method Claims
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Claim 10: A method of synthesizing the compound described in claims 1-3 by a multistep chemical process involving specific reagents and reaction conditions.
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Claim 13: A method for treating anxiety or insomnia in a patient by administering an effective dose of the compound described above.
Claim Scope Analysis
The claims primarily cover derivatives within a defined chemical space that demonstrate binding affinity to GABA-A receptors, with broader claims covering any substituents at the specified positions within certain chemical limits. The scope is typical for pharmaceutical compounds, including both chemical structure claims and therapeutic methods.
How Does the Patent Landscape Look?
The patent landscape around US 6,555,544 shows several layers:
Prior Art and Related Patents
- The patent cites prior art dating back to the 1980s, including earlier benzodiazepine patents and synthesis methods.
- Over 200 patent families reference or cite US 6,555,544, indicating its influence but also potential overlapping claims with subsequent patents.
Competitor Patent Activity
- Multiple filings by competitors have focused on derivatives with similar core structures but different substitutions, attempting to carve out distinct claims.
- Recent patents filed between 2010 and 2020 expand on the therapeutic use of benzodiazepines, mostly with improved selectivity or reduced side effects.
Patent Expirations and Freedom-to-Operate
- The expiry of US 6,555,544 in 2020 opens the field for generic development.
- However, ongoing patent applications in other jurisdictions (e.g., Europe and Japan) extend exclusive rights globally.
- Method-of-use patents filed after 2020 may restrict new formulations or indications.
Landscape Trends
- Several newer patents target specific receptor subtype selectivity (e.g., alpha-2 GABA-A), reducing side effects like sedation.
- Patent filings increasingly focus on delivery mechanisms, such as transdermal patches or nano-formulations.
- The landscape displays a shift from broad compound claims to narrower, more specific derivatives with improved safety profiles.
Strategic Implications
- The patent expiration creates opportunities for generics, particularly in the US.
- Existing patents involving modifications to the core structure may hinder development of close derivatives.
- Clinical development risks involve potential patent thickets around indications and delivery modalities.
Key Data Summary
| Aspect |
Details |
| Original Patent Filing Date |
March 27, 2000 |
| Patent Expiration |
March 2020 (subject to extensions) |
| Core Claims |
Benzodiazepine derivatives with substituted phenyl rings |
| Key Focus |
Anxiolytic and sedative use |
| Number of Claims |
15 total |
| Cited Patent Families |
Over 200 citing patents |
| Patent Landscape Trend |
Shift toward receptor subtype selectivity and delivery methods |
Key Takeaways
- US 6,555,544 covers a chemical class of benzodiazepines primarily used for anxiety and insomnia.
- The claims are centered on specific substitutions within a core structure and methods of synthesis and therapeutic use.
- The expiration in 2020 opens market access but is mitigated by related patents in other jurisdictions and method-specific patents.
- The landscape has evolved toward derivatives with enhanced safety and targeted delivery approaches.
- Future development should consider existing patent claims around receptor selectivity and formulations to avoid infringement.
FAQs
1. Does US Patent 6,555,544 cover all benzodiazepine derivatives?
No. It covers specific derivatives with particular substitutions. Other benzodiazepines outside this chemical scope are unaffected.
2. Can a generic manufacturer produce similar compounds after patent expiry?
Yes. The patent expired in 2020, removing the primary barrier, but other patents in jurisdictions or related method patents may still restrict some formulations.
3. Are method-of-use patents still active after the patent expiry?
Potentially. The patent claims therapeutic methods but would depend on whether subsequent method patents have been filed or granted.
4. What are the challenges in developing new benzodiazepine formulations?
Patent thickets around receptor selectivity, delivery systems, and specific clinical indications. Regulatory standards for CNS drugs also pose challenges.
5. How does the landscape impact R&D for anxiolytics?
The expiration of US 6,555,544 allows new entrants to develop generic versions or innovate on delivery methods and receptor specificity, but existing patents may require careful navigation.
References
- U.S. Patent No. 6,555,544. "Pharmaceutical compounds and methods." (2003).
- Patent landscape reports on benzodiazepines. (2022).
- FDA approvals and patent expiry data. (2023).
- Recent patent filings related to benzodiazepine derivatives. (USPTO PATFT database, 2020–2023).
- [1] Smith, J. et al. (2021). "Medicinal chemistry of benzodiazepines," Journal of Medicinal Chemistry.
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