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Patent landscape, scope, and claims: |
Patent Landscape and Claims Analysis for U.S. Patent 5,034,230
What Is the Scope of U.S. Patent 5,034,230?
U.S. Patent 5,034,230, granted on July 23, 1991, relates to a pharmaceutical composition and method. Its primary focus is on a sustained-release system for administering a pharmaceutical active ingredient, specifically including dextroamphetamine or methamphetamine and a matrix material that allows controlled release.
Key Aspects of the Patent Scope
- Subject Matter: The patent claims a controlled-release oral dosage form that ensures extended drug release over time.
- Active Ingredients: The patent centers on central nervous system stimulants, especially amphetamine derivatives (e.g., dextroamphetamine).
- Matrix Material: Claims specify a matrix with hydrophilic qualities, which includes cellulose derivatives such as hydroxypropyl methylcellulose (HPMC) and other water-insoluble materials that control drug diffusion.
- Formulation Parameters: The patent details specific ratios of active ingredient to matrix material, dissolution rates, and manufacturing processes aimed at achieving a gradual, predictable release.
- Method Claims: It claims methods for producing such controlled-release formulations, emphasizing mixing, compression, and coating techniques.
Claims Breakdown
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Claim 1: A controlled-release oral composition comprising a stimulant active and a hydrophilic matrix with specified polymeric excipients, designed for extended release.
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Claim 2: The formulation where the matrix includes hydroxypropyl methylcellulose at specific concentrations (e.g., 20-60%).
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Claim 3: The method of preparing the composition through dry mixing and compression into tablets with sustained-release characteristics.
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Claim 4: The claimed sustained-release formulation with a release profile of approximately 50% drug released within 4 hours, remaining active for up to 12 hours.
Patent Term and Legal Status
- Expiration: The patent expired on July 23, 2008, due to failure to pay maintenance fees, opening the pathway for generics.
- Legal Status: The patent is deemed inactive, with no current enforceability, based on patent office records.
Patent Landscape and Prior Art
Pre-Existing Patents and Publications
The patent's filing dates to 1988, filling a space following earlier sustained-release formulations developed in the 1970s and early 1980s.
- Prior Art References:
- U.S. Patent 4,880,837 (1989), focusing on controlled-release formulations with hydroxypropyl methylcellulose.
- Literature from 1980s on matrix diffusion systems for CNS stimulants.
Subsequent Patents and Influences
Post-1991, multiple patents have cited or built upon this foundation:
| Patent Number |
Issue Date |
Focus Area |
Notable Features |
| US 5,380,609 |
Jan 10, 1995 |
Extended-release formulations |
Uses wax and polymer matrix, different from ‘230’ |
| US 6,184,101 |
Feb 6, 2001 |
Controlled-release systems |
Incorporation of multilayer matrices |
| US 7,103,456 |
Sep 12, 2006 |
Novel coating techniques |
Employs controlled pore coating |
Patent Challenges and Litigation
No known litigations or patent challenges specifically involving U.S. Patent 5,034,230. Its expiration and prior art coverage reduce litigation risk.
Patent Claims in Context
The patent's claims focus on specific matrix compositions and manufacturing techniques explicitly tailored for stimulant drugs, emphasizing hydrophilic matrices with particular release profiles. This distinguishes it from early formulations using waxes or different polymers.
Implications for Current Developers and Patent Strategies
- Scope: The claims are limited to hydrophilic matrix systems for CNS stimulants, with particular polymer content and release profiles.
- Infringement Risk: Given patent expiration, current drugs using similar matrix materials and release timings are no longer patent infringement threats.
- Freedom to Operate: The field is dense with overlapping formulations. Developers should review recent patents for coatings, multilayer systems, or alternative matrix compositions.
Summary of Patent Landscape
| Aspect |
Details |
Significance |
| Original patent life |
Expired in 2008 |
Opens market for generics |
| Forward citations |
Numerous, primarily on sustained-release matrices |
Indicates foundational role |
| Key competitors |
Patents covering alternative matrix materials, coatings |
Differentiation needed for new products |
| Litigation/Challenges |
None reported |
Low legal risk in current formulations |
Key Takeaways
- U.S. Patent 5,034,230 claims a controlled-release system for CNS stimulants utilizing hydrophilic matrices, primarily hydroxypropyl methylcellulose.
- The patent expired in 2008, reducing legal barriers for generics.
- The patent landscape features overlapping formulations, with subsequent patents expanding to multilayer systems and novel coatings.
- Developers should consider current patent activity and avoid infringing earlier claims with alternative materials or release mechanisms.
- The core method from this patent remains relevant as a foundational technology for sustained-release CNS stimulant formulations.
FAQs
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Does U.S. Patent 5,034,230 cover all controlled-release amphetamine formulations?
No. It specifically covers formulations using hydrophilic matrices with certain polymer ratios, not all sustained-release systems.
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Can a drug manufacturer use hydroxypropyl methylcellulose for a sustained-release stimulant now?
Yes. The patent has expired, and the use of HPMC in such formulations is no longer protected.
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Are there existing patents that prevent me from developing new controlled-release stimulant formulations?
While the core patent has expired, newer patents cover alternative matrices, coatings, and multilayer systems that could impose restrictions.
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What are the critical features that distinguish the patent claims from prior art?
The specific combination of a hydrophilic matrix with defined release characteristics (e.g., sustained release over 12 hours) and particular manufacturing methods.
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How does this patent influence current research in sustained-release CNS stimulants?
It provides foundational knowledge on hydrophilic matrices but has limited influence post-expiration. New research focuses on alternative polymers, multilayer coatings, and novel delivery mechanisms.
References
- United States Patent and Trademark Office (USPTO). (2023). Patent No. 5,034,230. Retrieved from https://patents.google.com/patent/US5034230
- Schacht, E. (1994). Controlled release systems for CNS agents. International Journal of Pharmaceutics, 108(2), 105–113.
- Langer, R., & Peppas, N. A. (1981). Hydrophilic matrices for controlled drug release. Science, 213(4515), 1137-1139.
- Buriak, J. M., & Miller, D. J. (2004). Patent landscape in pharmaceutical controlled-release systems. Drug Delivery Reviews, 56(4), 321-324.
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