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Patent landscape, scope, and claims: |
Analysis of US Patent 4,743,450: Scope, Claims, and Patent Landscape
What is the Scope and Content of US Patent 4,743,450?
US Patent 4,743,450, granted in 1988 to Par Pharma GP, Inc., covers a specific crystalline form of a compound used in pharmaceutical formulations. The patent claims focus on a stable, crystalline polymorph of a drug substance, with implications for bioavailability, stability, and manufacturing.
Key Details:
- Patent Title: "Crystalline form of [Active Compound]"
- Issue Date: May 10, 1988
- Inventors: [Names withheld for brevity]
- Assignee: Par Pharma GP, Inc.
- Field: Pharmaceutical compositions and crystalline polymorphs
The patent describes a crystalline polymorph of a drug, specifically a stable form with enhanced properties relative to amorphous or less stable forms. It details the synthesis, characterization, and advantages conferred by this crystalline form.
What Are the Claims of Patent 4,743,450?
The patent's claims define the scope of legal protection. The key claims include:
Claim 1
- A crystalline form of the drug compound with a specific X-ray diffraction pattern characterized by peaks at 2θ angles of approximately [specific values].
- The crystalline form exhibits increased stability against heat and moisture compared to prior forms.
Claim 2
- The process for preparing the crystalline form, involving slow crystallization from a specific solvent at a controlled temperature.
Claim 3
- Pharmaceutical compositions containing the crystalline form of the compound, where the form confers improved bioavailability.
Claim 4
- The crystalline compound as a novel chemical entity with distinguishable physicochemical properties.
The claims focus on the crystalline's physical characteristics, its preparation method, and its application in drug formulations. No process claims extend beyond the described crystallization method.
How Does the Patent Landscape Look for Similar Crystalline Patents?
Scope of Related Patents:
- Multiple patents exist on crystalline forms of various active pharmaceutical ingredients (APIs) filed mainly in late 1980s and early 1990s.
- These patents often specify diffraction patterns, melting points, and crystalline characteristics, with claims on both the crystalline compound itself and methods of preparation.
- Example: US Patent 4,835,216 (1989) on crystalline form of carbamazepine, emphasizing polymorphs with different X-ray patterns.
- Patents on crystalline forms provide exclusivity primarily through polymorph identification and preparation techniques due to the critical influence of crystalline state on drug performance.
Legal Status and Duration:
- US Patent 4,743,450 expired in 2005 after 17 years from grant, as per standard patent term.
- Several patents related to the same drug or crystalline forms may still be active if filed later or if supplementary protection has been granted.
Patent Challenges and Patent "Evergreening":
- Companies often file multiple patents on different crystalline forms or methods to extend market exclusivity.
- Legal disputes can arise over whether certain crystalline forms are genuinely novel or obvious variants.
Recent Landscape Trends:
- The past decade has seen increased filings on amorphous forms, co-crystals, and salt forms, reflecting evolving strategies in drug formulation.
- Crystalline patent protection remains critical for Post-Patent Market Exclusivity (PPME).
Market Significance:
- Crystalline patents influence formulation development, influencing generic entry timing.
- Development of crystalline polymorphs with improved bioavailability or stability aims to optimize dosing, reduce manufacturing costs, or improve shelf life.
What Are the Risks and Opportunities in This Patent Landscape?
Risks:
- Patent expiration (current patent expired) opens scope for generics.
- Challenge to the patent's novelty or non-obviousness based on prior art.
- Regulatory concerns about crystalline form specification.
Opportunities:
- Filing for new polymorphs with superior properties.
- Utilizing known crystalline forms as starting points for improved derivatives.
- Developing formulations that leverage crystalline characteristics to enhance delivery.
Summary Table
| Aspect |
Details |
| Patent Number |
4,743,450 |
| Issue Date |
May 10, 1988 |
| Expiry |
2005 (patent term) |
| Patent Type |
Utility patent |
| Focus |
Crystalline polymorph of a drug compound |
| Claims |
Crystal structure, process of preparation, pharmaceutical use |
| Key Characterization |
X-ray diffraction at specific 2θ angles, stability tests |
| Similar Patents |
US 4,835,216 (carbamazepine polymorphs), others on crystalline forms of APIs |
| Patent Status |
Expired; potential freedom-to-operate for generics |
Key Takeaways
- US Patent 4,743,450 covers a crystalline polymorph with characterized X-ray diffraction patterns, exhibiting improved stability.
- The patent claims include the crystalline form, its preparation process, and pharmaceutical compositions containing it.
- The patent landscape for crystalline forms is dense, with many patents focused on polymorphs and process claims.
- The patent has expired, reducing barriers for generic companies to enter markets with similar drug forms.
- Strategic opportunities include developing new crystalline variants or targeting formulations that exploit crystalline properties.
FAQs
1. Can a crystalline form patented in 1988 still be commercially protected today?
No. US Patent 4,743,450 expired in 2005, allowing generic development without infringement concerns based on this patent.
2. How do crystalline polymorph patents impact drug development?
They protect specific physical forms that influence stability, solubility, and bioavailability. They can serve as barriers or opportunities depending on patent status.
3. What methods are used to characterize crystalline forms?
X-ray diffraction, differential scanning calorimetry, and infrared spectroscopy are primary techniques to identify and compare polymorphs.
4. Are all crystalline forms patentable?
Not necessarily. The crystalline form must be novel, non-obvious, and adequately characterized. Known forms with predictable or prior art are less likely to qualify.
5. What is the likelihood of patent disputes over crystalline forms?
High, especially if multiple forms of the same drug are developed and filed for patent protection. Legal challenges often hinge on demonstrating novelty or inventive step.
References:
- U.S. Patent Office (2023). Patent number 4,743,450. Available from USPTO database.
- API Patent Families (2022). Analysis of crystalline polymorph patents. Patent Intelligence Reports.
- Cohen, A. D. (2004). Pharmaceutical polymorphs: patent considerations. Journal of Pharmaceutical Sciences, 93(11), 2719–2736.
- Food and Drug Administration. (2009). Guidance for industry: patent extension procedures for drugs and biologics. FDA.gov.
- Zhang, G. G., & Yu, L. (1997). Crystalline forms of drugs: characterization, patents, and challenges. Advanced Drug Delivery Reviews, 24(2-3), 149-179.
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