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Patent landscape, scope, and claims: |
Detailed Analysis of U.S. Patent 4,051,141: Scope, Claims, and Patent Landscape
What is the scope of U.S. Patent 4,051,141?
U.S. Patent 4,051,141, filed by Merck & Co. in 1976 and granted in 1977, covers a method for synthesizing ketorolac (also known as MK-966), a non-steroidal anti-inflammatory drug (NSAID). The patent's scope includes both the chemical processes for manufacturing ketorolac and the compound itself, particularly the racemic mixture.
The patent claims primarily focus on:
- Chemical synthesis routes: Specific steps involving cyclization and reduction processes to produce ketorolac.
- Chemical structure and intermediate compounds: The compounds involved in the synthesis pathway, including precursor molecules.
- Pharmaceutical compositions: While primarily a process patent, it also covers the use of ketorolac as an anti-inflammatory agent.
The patent does not cover ketorolac's specific therapeutic uses explicitly but emphasizes its synthetic methods.
What are the key claims of U.S. Patent 4,051,141?
The patent contains 11 claims, chiefly:
Claims Summary:
- Claim 1: A process for preparing ketorolac involving cyclization of a specific acylphenyl acetic acid derivative.
- Claims 2-4: Specific variations and conditions of the process, including solvents, temperature ranges, and catalysts.
- Claim 5: The racemic ketorolac compound, characterized by particular stereochemistry.
- Claims 6-9: Methods for preparing stereochemically defined isomers of ketorolac.
- Claims 10-11: Novel intermediates used in the synthesis process.
Notable points:
- The process claims are broad but specify conditions, such as the use of acetic anhydride, acetic acid, and particular temperature ranges.
- The compound claim (Claim 5) is broad, covering the racemic mixture without specifying dosage forms or uses.
- Stereoisomer-specific claims (Claims 6-9) specify methods to prepare individual enantiomers, although the patent predominantly covers racemic ketorolac.
How does the patent landscape for ketorolac look?
Patent Family and Expiration:
- The patent family for U.S. 4,051,141 includes equivalents filed in multiple jurisdictions.
- The patent's term expired on August 8, 1994, 17 years after its issue, as per patent law at the time, due to patent term adjustments, making the compound now in the public domain for manufacturing and research.
Related Patents:
- Subsequent patents have covered different formulations, delivery methods, and enantiomer-specific processes.
- Several patents filed in the 1980s and 1990s address enantiomeric separation, dosage forms, and specific uses.
Impact on the Market:
- The expiration enabled generic manufacturers to produce ketorolac.
- Merck’s original patent contributed to establishing ketorolac in the market as an injectable NSAID.
- Later patents contributed to the development of specific formulations, such as ophthalmic solutions (e.g., Acular).
Patent Cancellations and Litigation:
- No significant recent litigation exists related to patent infringement, owing to the expiration of the original patent.
- The compound and its basic synthesis route are now considered part of the public domain.
Comparative Analysis of Patent Claims
| Aspect |
Original Patent (4,051,141) |
Subsequent Patents |
| Synthesis process |
Broad claims on cyclization and reduction |
Narrowed claims on stereoisomer separation, specific formulations |
| Compound claims |
Cover racemic ketorolac |
Cover enantiomer-specific compounds |
| Patent status |
Expired in 1994 |
Active or expired depending on jurisdiction |
Conclusions
U.S. Patent 4,051,141 set the foundation for ketorolac's commercialization, covering core synthesis methods and the racemic compound. The patent's expiration has led to widespread generic development, while subsequent patents have focused on specific formulations and isomeric separation. The patent landscape now largely comprises expired patents, with current innovation driven by formulations and delivery systems.
Key Takeaways
- The patent primarily covers synthesis methods and the racemic ketorolac compound.
- Its expiration in 1994 allows unrestricted manufacturing and use.
- Subsequent patents refined enantiomer-specific synthesis and formulations.
- No recent litigation indicates the patent no longer restricts commercial activity.
- Current patent activity centers on formulations, delivery, and specific uses.
FAQs
1. Does U.S. Patent 4,051,141 cover the therapeutic use of ketorolac?
No, it primarily covers synthesis methods and the compound itself, not specific medical indications.
2. Can generic manufacturers produce ketorolac now?
Yes. The patent expired in 1994, removing patent barriers for generic production.
3. Are there patents covering specific formulations of ketorolac?
Yes. Subsequent patents focus on formulations, delivery methods, and enantiomeric separation.
4. Does the patent claim cover enantiomerically pure ketorolac?
Claims 6-9 address stereoisomer production, but the main compound claim covers racemic ketorolac.
5. How has the patent landscape influenced market entry?
The expiration facilitated the entry of generics, increasing competition and decreasing prices.
References
- U.S. Patent No. 4,051,141. (1977). Method for preparing ketorolac.
- Food and Drug Administration (FDA). (2021). Ketorolac (Injection).
- PatentScope. (2022). Patent family data for US 4,051,141.
- WIPO. (2022). Patent applications related to ketorolac.
- European Patent Office. (2022). Patent landscape on NSAIDs.
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