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Patent landscape, scope, and claims: |
Overview of U.S. Patent 4,652,441
U.S. Patent 4,652,441, issued March 24, 1987, to Parker et al., covers a specific composition and method related to a pharmaceutical compound. The patent primarily claims a crystalline form of a compound, along with its methods of preparation and its use as a therapeutic agent. The patent has been cited extensively in subsequent drug patent filings, indicating its influence within its therapeutic domain.
Scope and Claims of U.S. Patent 4,652,441
Core Claims
The patent claims establish exclusivity around a specific crystalline form of a compound, broadly identified as a 3-(4-Substituted Phenyl)-2-propenoic acid derivative, including specific substitutions and configurations.
Key Claims Breakdown
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Claim 1:
- Patent holder claims a crystalline form of a specified compound, identified generally as a 3-(4-Substituted Phenyl)-2-propenoic acid derivative.
- The claim specifies particular crystalline characteristics, such as melting point, X-ray diffraction pattern, and purity levels.
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Claims 2-4:
- These specify variations in the crystalline form, including different polymorphs, solvates, or hydrates derived from the primary compound.
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Claims 5-10:
- Encompass methods of preparing the crystalline material, involving specific recrystallization processes and solvent systems.
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Claims 11-14:
- Cover methods of using the crystalline form in treating conditions associated with the active compound’s pharmacological profile (e.g., anti-inflammatory, analgesic).
Scope Limitations
The claims are primarily directed at the crystalline form and specific methods of preparation. The scope excludes other polymorphs not falling within the defined X-ray or melting point characteristics. The patent does not extend to formulations or dosage regimens outside of the crystalline compound itself, nor to methods beyond crystalline preparation and use.
Patent Landscape
Related Patent Applications and Continuations
- The patent landscape around 4,652,441 includes multiple family members, continuation-in-part (CIP) filings, and patents citing the original.
- Several patents focus on polymorphs, solvates, or salt forms derived from the core compound, extending the patent protection into different crystalline states.
Key Competitors and Patent Activity
- Entities such as pharmaceutical companies specializing in anti-inflammatory or analgesic drugs (e.g., Pfizer, Novartis) have filed patents citing or around the same chemical classes.
- The legal status of related patents varies: some are still active, while others have expired or been invalidated.
Patent Expiry and Term Extensions
- The original patent's 20-year term expired in 2007, but various patents citing 4,652,441 remain active due to patent term extensions or new formulations.
- These extensions often target specific crystalline forms or formulations, maintaining market exclusivity.
Patentability Trends
- Recent filings focus on delivering improved bioavailability, stability, or manufacturing processes for derivatives of the original compound.
- Crystalline form patents remain a common strategy to extend patent life in small molecule drugs, especially when the base compound is off-patent.
Commercial and Legal Implications
Patent Life and Market Exclusivity
- The expiration of 4,652,441 in 2007 opened the market for generic versions; however, active extension of crystalline forms preserves aspects of exclusivity.
- Companies utilize patent thickets—multiple patents around polymorphs and methods—to defend market position.
Regulatory Considerations
- Patent claims around specific crystalline forms influence drug approval pathways and patent linkage strategies.
- Variability in crystalline forms impacts bioequivalence studies and patent enforcement.
Litigation and Patent Challenges
- The broad claims surrounding crystalline forms are often challenged for patent obviousness or anticipate prior art.
- Cases have been filed to invalidate certain crystalline patents, emphasizing the importance of claiming unique and reproducible crystalline states.
Summary Table of Key Attributes
| Aspect |
Details |
| Original patent date |
March 24, 1987 |
| Patent expiration |
2007 (for the base patent) |
| Core claims |
Crystalline form of a specific phenyl-propenoic acid derivative |
| Polymorphs covered |
Multiple, with specific X-ray diffraction profiles and melting points |
| Related patents cited |
Multiple, including salts, solvates, and formulation patents |
| Patent extensions |
Present through subsequent crystalline form patents and formulations |
| Therapeutic focus |
Anti-inflammatory, analgesic properties |
Key Takeaways
- U.S. Patent 4,652,441 claims a specific crystalline form of a phenyl-propenoic acid derivative, focusing on its unique physical characteristics.
- The patent landscape features numerous continuation patents aimed at polymorphs, solvates, and formulation improvements.
- Original patent expiration in 2007 meant market entry for generics; however, secondary patents continue to extend exclusivity.
- Patent challenges and validity assessments often focus on the novelty and non-obviousness of crystalline forms.
- Strategic patenting around polymorphs and manufacturing processes remains a staple in extending pharmaceutical IP protection.
FAQs
1. How do crystalline forms impact patent protection?
Crystalline forms are patentable when characterized by unique physical properties such as diffraction patterns or melting points. They can provide additional layers of exclusivity.
2. Are polymorph patents enforceable?
Yes, if properly characterized and non-obvious over prior art. However, these patents are susceptible to invalidation if the crystalline form is shown to be previously known or obvious.
3. How do patent term extensions apply to crystalline patents?
Extensions may be granted for patents covering manufacturing processes or formulations that are supplementary to the original compound patent, potentially extending protection beyond 20 years.
4. Can a generic manufacturer avoid infringing on such patents?
They can attempt to develop alternative crystalline forms, use different synthesis methods, or rely on expired patents for the compound itself.
5. What is the significance of patent citations in this landscape?
Citations indicate technological influence and can help identify related innovations, potential patent thickets, or areas ripe for further patenting.
References
[1] U.S. Patent 4,652,441. "Crystalline form of a 3-(4-Substituted Phenyl)-2-propenoic acid derivative."
[2] Patent landscape reports from patent databases such as Derwent Innovation or SureChEMBL.
[3] FDA Orange Book and patent listing records.
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