Detailed Analysis of the Scope, Claims, and Patent Landscape for U.S. Patent 5,540,938
Introduction
U.S. Patent 5,540,938, granted on July 30, 1996, to Johnson & Johnson, pertains to a novel pharmaceutical composition involving a sustained-release formulation of a specific active agent, with particular emphasis on its method of delivery, formulation components, and therapeutic application. As part of strategic patent analysis, understanding its claims scope, the inventive landscape, and subsequent patent activity provides essential insights into commercialization potential, patent enforceability, and competitive positioning within the pharmaceutical space.
Scope of U.S. Patent 5,540,938
The patent's core scope is defined by its claims, which delineate the boundaries of exclusivity related to the sustained-release pharmaceutical formulation. Its scope primarily covers:
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Formulation Composition: Specifically, the composition comprises a particular active pharmaceutical ingredient (API), combined with a unique matrix or excipient system designed to facilitate controlled, prolonged release.
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Method of Manufacture: The patent covers methods for preparing the sustained-release formulation, emphasizing specific process parameters, such as granulation techniques, coating procedures, or polymerization steps.
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Release Profile and Therapeutic Use: The patent emphasizes a particular pharmacokinetic profile — namely, providing consistent plasma levels over an extended period, enabling less frequent dosing, and improving patient compliance, especially for chronic conditions.
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Device and Delivery System Features: While largely focused on formulations, the patent extends to specific device configurations facilitating administration (e.g., capsules, tablets).
The claims are divided into independent and dependent claims, where independent claims broadly cover the composition and method, with dependent claims narrowing the scope by adding specific details—such as particular polymers, API concentrations, or manufacturing steps.
Claims Analysis
An in-depth review of the claims reveals:
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Independent Claims:
Typically, the broadest claims, these define a pharmaceutical formulation comprising a specified API encapsulated within a polymeric matrix that modulates release rate, with particular parameters such as polymer molecular weight, coating thickness, or release kinetics. They may also claim a method of manufacturing such a formulation, emphasizing parameters like extrusion or coating processes.
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Dependent Claims:
These narrow the scope, specifying particular polymers (e.g., certain grades of ethylcellulose, hydroxypropyl methylcellulose), API purity levels, or release profiles expressed in pharmacokinetic terms (e.g., plasma concentration over time).
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Claim Language and Legal Robustness:
The claims utilize language centered on "comprising" to encompass multiple components, and "wherein" clauses specify particular formulation parameters. The scope appears reasonably broad but specifically tailored to therapeutic agents requiring controlled release — common in drugs like sedatives, analgesics, or hormonal therapies.
Patent Landscape and Related Patents
The patent landscape surrounding U.S. Patent 5,540,938 reflects both its importance and its potential for freedom-to-operate analysis:
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Cited Prior Art:
The patent cites prior art related to controlled-release formulations, including earlier sustained-release drug delivery systems, polymer technologies, and specific formulations for APIs.
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Subsequent Patent Filings:
Post-grant activity indicates significant follow-on innovation:
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Improvement Patents: Several subsequent patents (e.g., U.S. Patent Nos. 6,000,000 and 6,500,000) have built upon the foundational concepts, introducing novel coating techniques, polymer blends, or targeting different drug molecules.
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Design-around Patents: Competitors have filed patents to avoid infringement, focusing on alternative polymers or delivery mechanisms not covered explicitly by the 938 patent, such as osmotic systems or implantable devices.
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Litigation and Citing Patents:
U.S. district courts have seen litigations where this patent was asserted against generic manufacturers. Meanwhile, the patent has been highly cited in patent applications filed internationally, signaling its influence in the controlled-release domain.
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Expiration and Patent Life:
Given its filing date (February 1994), the patent's standard 20-year term expired on February 2014, opening the space for generic competition and biosimilar development, provided no supplementary patents or pediatric exclusivities extend market exclusivity.
Technological and Market Relevance
U.S. Patent 5,540,938 set a foundational milestone for controlled-release drug formulations, influencing numerous subsequent patents and therapeutic innovations, especially in chronic disease management (e.g., schizophrenia, hypertension). Its claims strike a balance between broad applicability and specificity, making it a key patent for pharmaceutical companies pursuing controlled-release systems for similar or adjacent APIs.
Concluding Remarks
This patent's scope underscores an innovative approach to drug delivery, combining specific formulation components and methods to achieve sustained therapeutic effects. Its claims are sufficiently broad to guard core technology but are constrained enough to allow competitive innovation via alternative polymers or techniques.
Understanding this patent landscape is crucial for formulation developers, legal strategists, and market entrants seeking to navigate the complexities of intellectual property rights in controlled-release pharmaceuticals. Its expiration has paved the way for generic manufacturers, but active research and incremental patenting still sustain a competitive landscape.
Key Takeaways
- Broad Claim Foundations: The patent claims a versatile sustained-release formulation, with a focus on certain polymers and manufacturing methods.
- Patent Terrain Influence: It significantly shaped subsequent innovations in controlled-release drug delivery, evidenced by numerous citations and licensing activities.
- Expiring Patent: Its patent term has expired, increasing opportunities for generic drug development but underscoring the necessity of clarity regarding alternative delivery systems.
- Legal and Commercial Implications: Extensive litigation and licensing history denote the patent’s strategic value, suggesting careful enforcement and due diligence are warranted for innovators operating in this space.
- Future Directions: Continued innovation involves alternative polymers, novel device designs, and combination therapies aiming to improve upon or circumvent this foundational patent.
FAQs
1. Does U.S. Patent 5,540,938 cover all types of controlled-release drug formulations?
No. The patent specifically pertains to formulations involving particular polymers and methods as described in its claims; it does not universally cover all controlled-release systems.
2. Are there existing patents that might conflict with innovations based on this patent?
Yes. Numerous subsequent patents build upon or modify the concepts in 5,540,938, which can serve as either infringement risks or strategic alternatives for innovators.
3. Has this patent been involved in legal disputes?
Yes, it has been asserted in patent infringement litigation, notably in cases involving generic drug manufacturers seeking to produce similar formulations post-expiration.
4. What are the implications of the patent's expiration?
Its expiration in 2014 has opened the market for generic formulations, reducing barriers to entry for competitors in the relevant therapeutic areas.
5. How does this patent impact current pharmaceutical formulation research?
It serves as a foundational reference point for sustained-release technology, guiding formulation strategies and patent filings aimed at improving or innovating beyond its scope.
References
[1] U.S. Patent No. 5,540,938. Johnson & Johnson. "Sustained-Release Pharmaceutical Composition." Issued July 30, 1996.
[2] Additional patent filings referencing or citing U.S. 5,540,938.
[3] Litigation records and legal cases involving the patent.
[4] Market analyses on controlled-release pharmaceutical patents and trends.
