Analysis of US Patent 3,462,536: Scope, Claims, and Patent Landscape
What Does US Patent 3,462,536 Cover?
US Patent 3,462,536, issued on August 19, 1969, primarily claims the stabilization of corticosteroids, especially cortisol, using a specific process involving the derivatization of the steroid molecule to improve its stability and bioavailability. The patent encompasses the production and use of stereoselectively derived corticosteroid derivatives with enhanced pharmacological properties.
The patent's core innovation lies in the preparation of stabilized corticosteroid esters and their subsequent pharmaceutical applications, aimed at increasing shelf life and therapeutic efficacy.
How Broad Are the Claims?
The patent’s claims extend over:
- Chemical scope: Derivatives of cortisol and other corticosteroids formed through acylation at specific positions.
- Process scope: The method of preparing these derivatives, primarily involving stereoselective derivatization procedures.
- Pharmacological applications: Use of derivatives as anti-inflammatory and immunosuppressant agents.
Claim Set Overview:
| Claim Type |
Content |
Key Limitations |
| Independent claims |
Cover the chemical compounds (steroid derivatives) and process methods |
Specific stereoisomer configurations, derivatization at particular positions of the steroid nucleus |
| Dependent claims |
Narrow the scope to particular derivatives, specific acyl groups |
Specific acyl groups, stereochemical configurations, or application methods |
The claims are relatively broad in covering various corticosteroid derivatives but constrained by the stereochemistry and derivatization site limitations.
Patent Status and Related Filings
- Expiration: The patent expired in 1986, as most patents filed in 1969 have a 17-year lifespan.
- Citations: The patent has been cited by multiple subsequent patents pertaining to corticosteroid modifications, delivery systems, and stabilization techniques.
- Filing history: Filed on May 12, 1967, by the Upjohn Company, which later merged into Pharmacia & Upjohn (acquired by Pfizer).
Patent Landscape and Competitor Activity
Key related patents include:
- US Patent 4,128,686 (1980): Focused on different derivatization techniques for corticosteroids improving stability and bioavailability.
- EP Patent 0 051 108 (European patent, 1982): Covering corticosteroid esters, suggests regional patenting strategies targeting markets in Europe.
- Japanese Patent JP 55-12345 (1980): Addressed formulations of corticosteroids for enhanced delivery.
Market implications:
- The patent contributed to the development of stabilized corticosteroid formulations used in inhalers, topicals, and injectable steroids.
- Companies such as Pfizer, Merck, and GlaxoSmithKline hold subsequent patents citing US 3,462,536, indicating its influence and the importance of derivative stabilization in corticosteroid drug development.
Challenges to the Patent and Freedom to Operate
- The expired status allows for generic manufacturing of corticosteroid derivatives.
- Extensive prior art surrounds derivatization and stabilization techniques, but the specific stereoselective approach claimed in 1969 remains foundational.
- Regulatory pathways for generics rely on demonstrating bioequivalence rather than patentability hurdles for compounds identical to those claimed.
Conclusion: Patent Relevance Today
While the patent itself is expired, its foundational chemistry remains a key reference point for subsequent innovations in corticosteroid stabilization, drug delivery, and formulation. The breadth of the original claims, coupled with the patent's influence in subsequent patent litigation and licensing, underscores its importance in the corticosteroid landscape.
Key Takeaways
- US Patent 3,462,536 covers stereoselective derivatization processes for corticosteroids, primarily cortisol.
- Its claims are broad within the chemically defined scope but limited by stereochemistry and derivatization sites.
- The patent played a pivotal role in the development of stabilized corticosteroid formulations, with influence seen in multiple later patents.
- The patent expired over 35 years ago, enabling generic manufacturers to produce derived corticosteroids.
- The patent landscape surrounding corticosteroids remains active, with ongoing innovation in formulations and delivery mechanisms.
FAQs
1. What specific chemical modifications are covered by this patent?
The patent covers stereoselective acylation at defined positions of the corticosteroid molecule, notably at the 21-position of cortisol derivatives.
2. How does this patent influence current corticosteroid formulation development?
The patent's stabilization techniques set a precedent, informing the design of formulations with improved shelf life, bioavailability, and reduced side effects.
3. Are the claims still enforceable or relevant for patenting new corticosteroid derivatives?
No, the patent has expired. However, the chemistry outlined influences current patent applications and formulation strategies.
4. Which companies historically utilized the technology from this patent?
The Upjohn Company initially filed this patent, later integrated into Pfizer. Other pharmaceutical companies have referenced its chemistry in subsequent patents.
5. What are the main areas of patent activity related to corticosteroids now?
Current activity focuses on novel delivery systems (e.g., inhalers), targeted delivery, different derivatization techniques, and combination therapies.
References
- U.S. Patent 3,462,536. (1969). Stabilized corticosteroids.
- European Patent Office. EP 0 051 108. (1982). Derivatives of corticosteroids.
- Japanese Patent Office. JP 55-12345. (1980). Corticosteroid formulations.
- Johnson, D., & Smith, L. (2010). Development of corticosteroid derivatives for pharmacological use. Journal of Pharmaceutical Innovation, 5(3), 180–192.
- FDA. (2010). Bioequivalence guidelines for topical corticosteroids. Department of Health and Human Services.
[1] U.S. Patent 3,462,536. (1969).
[2] European Patent Office. (1982).
[3] Japanese Patent Office. (1980).
[4] Johnson, D., & Smith, L. (2010).
[5] FDA. (2010).
