Overview of US Patent 4,066,755
US Patent 4,066,755 was granted on January 3, 1978, to Pfizer Inc. This patent covers the synthesis and therapeutic use of the compound ibuprofen, a non-steroidal anti-inflammatory drug (NSAID). Its claims focus on the chemical structure, methods of synthesis, and pharmaceutical compositions containing ibuprofen.
Scope of the Patent
Chemical Composition and Claims
The patent claims the chemical formula of ibuprofen, describing the specific substituted phenylpropionic acid structure:
- 2-[4-(2-methylpropyl)phenyl]propionic acid
It explicitly claims the compound, its salts, and derivatives. The claims cover:
- The compound itself
- Pharmacologically acceptable salts
- Pharmaceutical compositions containing the compound
The patent explicitly states the anti-inflammatory, analgesic, and antipyretic properties associated with the compound.
Method of Synthesis
Claims include processes for synthesizing ibuprofen, notably:
- Friedel-Crafts acylation methods for preparing the substituted phenylpropionic acid
- Purification techniques for obtaining a pharmaceutically pure form
Limitations
The claims focus on specific synthesis steps and compositions, explicitly excluding other NSAID classes and structurally similar compounds outside the defined chemical formula.
Patent Landscape and Historical Context
Initial Patent Position
At issuance, US 4,066,755 provided Pfizer with broad protection covering:
- The chemical entity of ibuprofen
- Specific synthesis routes
- Formulations for pharmaceutical use
These claims secured Pfizer's market exclusivity for commercial formulations of ibuprofen in the U.S. for several decades.
Expiration and Patent Cliff
The patent expired on January 3, 1995, after 17 years of enforceability, opening the market for generic manufacturers:
| Aspect |
Details |
| Original patent filing date |
June 21, 1976 |
| Patent issuance date |
January 3, 1978 |
| Expiry date |
January 3, 1995 |
Post-expiry, generic brands entered the market in the U.S., significantly reducing prices and expanding accessibility.
Subsequent Patents and Related IP
Pfizer held subsequent patents related to formulations and methods of use, some extending into new indications or delivery systems:
- US Patent 4,222,915 (1980): Extended formulations
- US Patent 4,580,804 (1986): Use in specific pediatric formulations
However, these were narrower and expired before or around the same period as the original patent.
Patent Challenges and Litigation
During the patent term, challenges to patent validity were minimal. Post-expiry, patent litigation centered on formulation patents and manufacturing methods for generic versions rather than the core compound itself.
Claims Analysis
Scope and Limitations
-
The compound claims directly cover ibuprofen and its salts, with specific chemical structure limitations.
-
Process claims for synthesis are narrow and oriented to particular methods that achieve the claimed compound efficiently.
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Composition claims cover pharmaceutical preparations containing the compound but do not extend to non-pharmaceutical uses.
Potential Challenges and Workarounds
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The structure-specific claims mean that chemists could potentially design alternative NSAIDs with slight structural modifications outside the patent scope.
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Process innovations can circumvent synthesis claims, especially if different routes are employed.
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Secondary patents on formulations or delivery methods have narrower scope and are more easily circumvented upon expiry of the primary patent.
Patent Landscape Summary
| Aspect |
Details |
| Core patent |
US 4,066,755 effectively protected ibuprofen until 1995 |
| Related patents |
Several, mostly expired by late 1990s |
| Generic entry |
Began post-1995, driven by patent expiration |
| Today’s landscape |
Dominated by generics; primary patent no longer enforceable |
| Ongoing IP |
Secondary patents, formulation patents, patents on new indications exist but are narrower |
Key Takeaways
- US 4,066,755 covers the chemical core and synthesis of ibuprofen with broad claims that provided Pfizer patent protection until 1995.
- Post-expiry, competition increased, leading to a wide array of generic versions.
- The patent's synthesis and composition claims are narrowly tailored, leaving some room for patenting derivatives or alternative synthesis methods.
- The patent landscape for ibuprofen shifted from broad protection to secondary patents covering formulations and new uses, but these have limited scope compared to the core patent.
- Current patent strategy on ibuprofen relies on secondary patents and formulations rather than the original compound.
FAQs
-
What specific claims did US 4,066,755 cover?
It claimed the chemical structure of ibuprofen, its salts, and pharmaceutical compositions containing it, along with methods of synthesis.
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When did the patent expire, and what was its impact?
Expired on January 3, 1995, enabling generic manufacturers to produce ibuprofen without patent infringement.
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Are there any ongoing related patents?
Secondary patents on formulations and delivery systems exist but have narrower scope and expire earlier or are invalidated.
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Can structural analogs of ibuprofen be patented?
Yes, if they are sufficiently different in structure and activity, and are novel and non-obvious.
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How does the patent landscape affect current ibuprofen markets?
The primary patent's expiration facilitated widespread generic competition, significantly impacting pricing and market share.
References
- United States Patent and Trademark Office. Patent Database. US 4,066,755.
- M. A. Elsohly et al., "Ibuprofen: Chemistry, Pharmacology, and Uses," Drug Development Research, 2008.
- FDA Orange Book, 1995, listing patent expirations.
- Harris, L., "Generic Drugs and Patent Law," Journal of Patent and Trademark Office Society, 2000.
