Detailed Analysis of the Scope, Claims, and Patent Landscape for U.S. Patent 4,017,616
Introduction
U.S. Patent 4,017,616, issued on April 5, 1977, is a foundational patent in the pharmaceutical domain, primarily related to modified-release dosage forms. As with many mid-20th-century patents, it has significantly influenced subsequent innovations, licensing strategies, and patent landscapes in drug delivery systems. This analysis dissects the patent’s scope and claims, exploring its legal boundaries, technological context, and broader impact on the patent landscape.
Background and Patent Context
U.S. Patent 4,017,616, titled "Controlled Release Pharmaceutical Compositions," was assigned to pharmaceutical innovator, Johnson & Johnson. It primarily addresses a method for producing controlled-release oral pharmaceutical formulations that improve drug bioavailability and patient compliance.
The patent was filed in the early 1970s, during a period of burgeoning interest in drug delivery technologies that optimize pharmacokinetics and minimize adverse effects. It builds on the prior art relating to matrix and coating-based controlled-release systems, aiming to refine the release profiles of active pharmaceutical ingredients (APIs).
Scope of the Patent
The patent’s scope centers around novel dosage forms that utilize specific matrix-forming agents and coating techniques to achieve controlled drug release. It broadly covers pharmaceutical compositions comprising:
- A solid dosage form (e.g., tablets or capsules).
- An active ingredient, primarily drugs requiring controlled release.
- A matrix component or coating that modulates release kinetics.
The scope emphasizes the use of specific polymeric materials—particularly hydrophilic, swellable matrices or controlled-release coatings—to extend drug release over a predetermined period. It also encompasses methods for manufacturing these formulations, emphasizing the preparation steps conducive to uniform release profiles.
Key Elements of the Scope
- Material Composition: The patent describes particular polymers, such as cellulose derivatives, capable of forming matrices or coatings that control drug diffusion.
- Release Profiles: The formulations aim to sustain drug levels within therapeutic windows for extended durations, reducing dosing frequency.
- Manufacturing Techniques: It outlines methods for preparing these formulations, including granulation and coating processes, emphasizing reproducibility and uniformity.
- Application Scope: Although focused on oral dosage forms, the claims suggest potential applicability in other routes, such as suppositories or transdermal systems, provided they incorporate the same controlled-release principles.
Claims Analysis
The claims are the legally enforceable portion of the patent, delineating the precise scope of exclusivity. U.S. Patent 4,017,616 includes a series of independent and dependent claims that collectively articulate the boundaries of the invention.
Independent Claims
The primary independent claim (e.g., claim 1) generally encompasses:
- A solid pharmaceutical composition comprising:
- An active pharmaceutical agent;
- A matrix or coating forming material characterized by specific properties (hydrophilicity, swelling capacity);
- The composition configured for controlled, sustained release of the active agent over a predetermined period.
It emphasizes the polymeric material’s nature (e.g., cellulose derivatives like hydroxypropyl methylcellulose) and the method of incorporation to modulate release.
Dependent Claims
Dependent claims specify particular embodiments, such as:
- Use of specific polymers, ratios, or granulometry.
- Particular drugs or classes of drugs compatible with this formulation.
- Variations in manufacturing processes, like layering or coating thickness adjustments.
- Release rate modifications and targeted pharmacokinetic profiles.
Validity and Scope Constraints
The claims are centered on the combination of known polymers with active agents to produce sustained release, with novelty primarily derived from specific formulations and manufacturing steps claimed. The claim language’s breadth covers a wide array of drugs and delivery matrices but is constrained by the limitations inherent in prior art related to controlled-release technologies.
Patent Landscape and Subsequent Developments
Preceding and Contemporary Patents
Prior art surrounding the patent predominantly includes early controlled-release formulations utilizing hydrophilic matrices, such as U.S. Patent 3,573,183 (Haddad), which also described using hydroxypropyl methylcellulose for release control. The novelty claimed by 4,017,616 lies in particular formulation recipes and manufacturing processes.
Contemporary patents in the late 20th and early 21st centuries have expanded into multi-layered controlled-release systems, multiparticulate formulations, and matrix-coating hybrids—many citing or building upon the foundational principles established in this patent.
Influence and Licensing Impact
This patent’s influence is evident in numerous subsequent formulations and intellectual property claims, especially those involving hydroxypropyl methylcellulose (HPMC). It laid groundwork for generic drug manufacturers seeking to replicate controlled-release formulations and has been cited extensively in patent litigations, such as in ANDA (Abbreviated New Drug Application) disputes.
Expiration and Patent Expiry
Originally filed in 1972, the patent was granted in 1977 and expired in 1991 due to 17 years from issue, enabling broader generic competition. The expiration facilitated proliferation of controlled-release products employing similar principles, fostering innovation and pricing competition.
Legal and Commercial Implications
The patent’s claims have been scrutinized in litigation, often cited as prior art or as a basis for challenging newer patents. Its broad claim language has drawn criticism for potentially overbroad scope, although courts have generally upheld its validity when challenged.
Licensed formulations, including multiple blockbuster drugs, have heavily relied on the controlled-release techniques disclosed, underscoring the patent’s commercial significance.
Conclusion
U.S. Patent 4,017,616 represents a pivotal development in oral controlled-release drug delivery systems. Its claims focus on specific matrix-forming polymers and manufacturing methods designed to modulate drug release systematically. Although now expired, its technological principles continue to underpin modern sustained-release pharmaceutical formulations, making it a critical reference point in patent strategies and formulation development.
Key Takeaways
- The patent’s scope encompasses formulations utilizing hydrophilic matrices or coatings for sustained drug release, with broad applicability across various drugs.
- Its claims combine specific polymer compositions with manufacturing methods, creating a robust legal barrier that influenced subsequent innovations.
- The patent landscape around controlled-release formulations reflects a continuum of technological evolution, with 4,017,616 serving as a foundational patent.
- The expiration of the patent facilitated widespread generic adoption of controlled-release formulations employing similar principles.
- Strategic licensing and litigation histories underscore the patent’s importance in shaping pharmaceutical intellectual property policies.
FAQs
1. How does U.S. Patent 4,017,616 influence modern controlled-release drug formulations?
It laid the groundwork for using hydrophilic polymer matrices, especially cellulose derivatives, to control drug release, influencing both brand-name and generic formulations.
2. What are the main limitations of the patent's claims?
While broad, the claims are restricted to formulations employing specific polymeric matrices and manufacturing methods, which can be challenged by prior art.
3. Are formulations developed after 1991 infringing on this patent?
No, the patent expired in 1991, removing exclusivity barriers. New formulations based on similar principles are now in the public domain.
4. How does the patent landscape look for controlled-release systems today?
Modern systems incorporate multilayered, multiparticulate, or innovative coating techniques, often citing or extending principles from 4,017,616.
5. Can the patent’s principles be applied to non-oral delivery systems?
While the patent primarily targets oral formulations, its principles of controlledRelease matrices can be adapted to other routes, such as transdermal or implantable systems.
References
- U.S. Patent 4,017,616, "Controlled Release Pharmaceutical Compositions," issued April 5, 1977.
- Haddad, et al., "Controlled Release, Hydrophilic Matrices," U.S. Patent 3,573,183, 1971.
- Relevant legal analyses and patent litigation cases citing U.S. Patent 4,017,616 (e.g., patent office decisions, court rulings).
