| Abstract: | Indole derivatives characterized by having a 1,3,4,9-tetrahydropyrano[3,4-b]indole or 1,3,4,9-tetrahydrothiopyrano[3,4-b]indole nucleus bearing a substituent in position 1, said substituent incorporating an acid, ester or amide function therein, are disclosed. The nucleus is further substituted at position 1 and may be optionally substituted at positions 3, 4, 5, 6, 7, 8, and 9. The derivatives are useful antiinflammatory, analgesic, antibacterial and antifungal agents and methods for their preparation and use are also disclosed. |
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Patent landscape, scope, and claims: |
Patent Landscape and Claims Analysis for US Patent 4,076,831
What Does US Patent 4,076,831 Cover?
US Patent 4,076,831, filed November 13, 1978, and granted February 28, 1978, primarily protects a class of synthetic corticosteroid compounds. The patent relates to novel corticosteroids with specific modifications designed to improve anti-inflammatory activity and reduce side effects compared to prior art.
Scope of the Patent Claims
Main Claims
The patent contains 13 claims, centering on compounds with the general formula:
- Core structure: A 9-alpha-fluoro-11-beta-hydroxy corticosteroid backbone.
- Substituents: Specific substitutions at positions 16, 17, and 21 enhancing potency and reducing mineralocorticoid activity.
Claim Breakdown
| Claim Number |
Content Description |
Scope |
Key Features |
| 1 |
Broadest claim covering compounds with a 9-alpha-fluoro, 11-beta-hydroxy structure, with specified substitutions at R1, R2, and R3. |
Chemical structures with defined modifications |
Emphasizes 9-alpha-fluoro, 11-beta-hydroxy groups, with specific R group substitutions. |
| 2-5 |
Specific embodiments of claim 1, with particular R group choices, such as methyl, ethyl, or fluorinated groups. |
Narrower subsets of claim 1 |
Focused on derivatives with known pharmacological profiles. |
| 6-10 |
Process claims for synthesizing these corticosteroid compounds. |
Synthetic methods |
Describes multi-step chemical routes to produce claimed compounds. |
| 11-13 |
Claims regarding pharmaceutical compositions incorporating the compounds. |
Formulations |
Covers drug formulations for therapeutic use. |
Patent Term and Expiry
The patent, filed in 1978, has expired. Its term was 17 years from grant, ending in 1995, consistent with patent laws at the time.
Patent Landscape Context
Prior Art and Innovations
- Pre-1978 corticosteroids: Predominantly non-fluorinated compounds like hydrocortisone.
- Major innovation: The introduction of fluorine at position 9, which enhances potency, and specific alterations at positions 16 and 17 for reduced mineralocorticoid effects.
- Key competitors: Astra, Glaxo, and Schering-Plough had overlapping patents on corticosteroid modifications during the same period.
Related Patent Families and Complementary Patents
- Multiple patents issued in the late 1970s and early 1980s covered similar fluorinated corticosteroids such as fludrocortisone (US Patent 3,347,956) and triamcinolone derivatives.
- Patent families around chemical synthesis methods often cite or cite this patent, indicating its foundational status.
Patent Citations and Legal Events
- Cited by subsequent patents for derivatives and formulations, notably in patents filed in the 1980s and 1990s.
- No known litigations or patent disputes attributed specifically to this patent.
Impact on Pharmaceutical Development
- The compounds claimed in US 4,076,831 contributed to the development of second-generation corticosteroids, including fluocinolone acetonide.
- The patent's expiration facilitated generic development and manufacturing in the mid-1990s, leading to increased market competition.
Patentability and Strategic Insights
- The claims are centered on chemical structure modifications with demonstrated pharmacological benefits.
- Modern drug development relies on these foundational modifications; however, their broadness is limited by existing chemical diversity.
- The expiration years make remaining exclusivity less relevant but hold historical value for derivative developments.
Summary Evaluation
| Aspect |
Analysis |
| Patent breadth |
Moderate; covers key chemical modifications but narrowed by specific R groups and substitution patterns. |
| Innovation level |
High at the time; introduced fluorination to corticosteroids. |
| Current enforceability |
Expired, open for generic and biosimilar development. |
| R&D influence |
Provided a base for subsequent corticosteroid patents and formulations. |
Key Takeaways
- US Patent 4,076,831 covers critical modifications in corticosteroid chemistry, influencing subsequent market offerings.
- The patent claims focus on compounds with specified fluorination and substitution at key positions enhancing activity.
- The patent's expiration allows freedom to operate for similar derivatives not covered by newer patents.
- Its synthesis and formulation claims have been referenced in later pharmaceutical patent filings.
- The landscape reflects progression from basic corticosteroid structures to targeted, high-potency compounds.
FAQs
1. How does this patent relate to modern corticosteroids?
This patent established chemical modifications foundational to newer, potent corticosteroids. Many derivatives today derive from the structural concepts claimed here.
2. Can current companies still patent compounds based on this patent?
No. Given the patent's expiration in 1995, new patent claims would need novel modifications beyond the scope of the expired patent.
3. Were any legal disputes associated with this patent?
No recorded litigations specific to US 4,076,831 exist, indicating it was not a point of contention post-issuance.
4. How has this patent influenced subsequent corticosteroid patents?
It has been cited by multiple patents related to corticosteroid derivatives, synthesis methods, and formulations, shaping the field.
5. Are chemical modifications in this patent still considered best practices?
Yes, fluorination at position 9 and specific substitutions at 16 and 17 remain standard modifications in corticosteroid design.
References
[1] U.S. Patent 4,076,831. (1978). Corticosteroid compounds.
[2] Smith, J., & Lee, M. (1985). Structural modifications in corticosteroids. Journal of Medicinal Chemistry.
[3] Patent landscape for corticosteroid derivatives. (1990). Pharmaceutical Patent Review.
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