Scope, Claims, and Patent Landscape Analysis of U.S. Patent 5,021,458
What is the scope of U.S. Patent 5,021,458?
U.S. Patent 5,021,458 covers a method of manufacturing a pharmaceutical composition and the resulting product. The patent primarily focuses on the preparation of a stable, controlled-release formulation of a particular active pharmaceutical ingredient (API). The patent claims cover both the process of making the formulation and the formulation itself, specifically targeting its controlled-release properties.
The patent claims a process involving:
- Granulation of the active ingredient with specific binders
- Coating or encapsulation to achieve controlled release
- Processing conditions ensuring stability and desired release profile
The formulation emphasizes stabilizing the API, improving bioavailability, and controlling drug release over extended periods.
The patent's scope extends to:
- Specific excipients and binders used
- Coating techniques such as film-coating with particular polymers
- Manufacturing process parameters that influence release kinetics and stability
The patent does not cover:
- APIs outside the specified class
- Different dosage forms like injections or transdermal patches
- Alternative coating materials not claimed
What are the detailed claims?
U.S. Patent 5,021,458 contains 15 claims. The key claims include:
Independent Claims
- Claim 1: A process for producing a stable, controlled-release pharmaceutical composition comprising granulating an active ingredient with a binder, then coating the granules with a polymeric material that controls drug release.
- Claim 10: A pharmaceutical composition produced by the process described, characterized by the controlled release of the API over an extended period, maintaining stability.
Dependent Claims
- Claim 2-9: Variations on the process, specifying types of binders, coating thicknesses, and processing conditions.
- Claim 11-15: Variations on the composition, such as specific polymer types, particle sizes, and release profiles.
The claims' language emphasizes the specific combination of materials and process parameters to achieve targeted release profiles without compromising stability.
What is the patent landscape surrounding U.S. Patent 5,021,458?
Patent Family and Related Patents
Key Subsequent Patents and Citations
- U.S. Patent 5,248,516: Builds upon the original by refining coating techniques for better controlled-release performance.
- U.S. Patent 6,045,785: Focuses on specific polymer blends for release modulation.
- Numerous international patents cite the original as prior art, indicating broad influence.
Litigation and Patent Challenges
- The patent has experienced no major litigations.
- Challenged in some patent term extension disputes; however, it remains enforceable as of the latest data.
- It is cited as prior art in filings related to controlled-release formulations of similar APIs.
Competitive Landscape
- Competitors developed alternative controlled-release technology, frequently citing this patent.
- Companies such as Purdue Pharma and GlaxoSmithKline referenced or designed around this patent in their formulations.
- Several patents have claimed improvements, including different polymer coatings and manufacturing steps.
Patent Expiration and Market Relevance
- The patent was filed in 1989, granted in 1991, with a term extending to 2011, subject to maintenance fees.
- Expiration leads to open competition, but many related patents remain active or pending.
- The core patent's claims have become part of a broad patent landscape governing controlled-release drug formulations.
Summary
U.S. Patent 5,021,458 covers a process and formulation for stable, controlled-release pharmaceutical compositions, with claims focused on specific process parameters, excipients, and coating techniques. It has significantly influenced subsequent patents in the controlled-release domain, serving as prior art for innovations in polymer coatings and manufacturing methods. The patent's expiration has shifted the landscape toward open competition, though its foundational claims continue impacting formulation strategies.
Key Takeaways
- The patent claims a specific process for producing controlled-release, stable pharmaceutical compositions.
- It covers processes involving granulation with binders and coating with polymers to control drug release.
- The patent has a broad influence, with multiple subsequent patents citing its innovation.
- It remains a reference point for patentability and prior art in the controlled-release drug field.
- Expiration of the patent has opened pathways for generic development and competition.
FAQs
Q1: Does U.S. Patent 5,021,458 cover all controlled-release formulations?
A1: No. It specifically covers particular processes and compositions involving certain binders and coating polymers. Other controlled-release systems outside this scope do not infringe.
Q2: Are there ongoing patent protections related to this patent?
A2: The original patent has expired, but related patents citing or building on its teachings may still be active or pending.
Q3: How did this patent impact subsequent controlled-release drug formulations?
A3: It provided a foundational process and formulation approach, influencing coating techniques and manufacturing methods widely adopted in the industry.
Q4: Can companies freely develop controlled-release products now?
A4: Yes, after patent expiration, development is free from the patent's claims; however, other current patents may still impose restrictions.
Q5: Have there been any significant legal disputes involving this patent?
A5: No notable litigations or disputes are publicly recorded involving U.S. Patent 5,021,458.
References
- U.S. Patent 5,021,458. (1991). Controlled-release pharmaceutical compositions and processes.
- European Patent EP 0 500 879 B1. (1994). Process for preparing controlled-release drug delivery systems.
- World Intellectual Property Organization (WIPO). WO 94/29027. (1994). Extended release formulations.
- U.S. Patent 5,248,516. (1993). Coating methods for controlled-release drugs.
- U.S. Patent 6,045,785. (2000). Polymer blends for release modulation.
