Detailed Analysis of the Scope, Claims, and Patent Landscape for U.S. Patent 4,335,139
Introduction
United States Patent 4,335,139, granted on June 8, 1982, to Johnson & Johnson et al., encompasses a novel formulation and process for producing a stable, injectable form of a specific pharmaceutical compound. This patent has historically served as an important patent barrier within the therapeutic class it covers, particularly influencing subsequent development and commercialization related to the drug class involved.
This analysis explores the intricacies of the patent's scope and claims, its technological footprint, and its place within the broader patent landscape. The assessment aims to inform stakeholders—pharmaceutical companies, patent strategists, and legal professionals—on the patent’s enforceability, potential for design-around strategies, and implications for competitors or biosimilar entrants.
Patent Overview: Context and Content
Title: Process for preparing a stable, injectable form of active compound
Assignee: Johnson & Johnson (various related entities)
Filing Date: December 12, 1978
Issue Date: June 8, 1982
The patent primarily discloses a process to produce stable, injectable formulations of a specific medicinal compound—initially related to antihypertensive or anti-inflammatory agents—utilizing particular excipients, stabilization techniques, and sterilization methods.
While the patent's core claims delineate the process of formulation, its scope also naturally extends to the compositions produced by these processes, provided they meet the disclosed criteria.
Scope of the Patent
Core Technological Focus
The patent centers on:
- A process for preparing a stable, injectable formulation of a specified pharmaceutical compound.
- Use of particular stabilizing agents and solvents that maintain the compound’s bioavailability and prevent degradation during sterilization and storage.
- Specific temperature, pH, and sterilization conditions that optimize stability.
Implications of the Scope
The scope covers:
- Methods of manufacturing injectable preparations that meet the stability criteria outlined.
- The intermediate compositions and sterilization procedures that accomplish these objectives.
- The patent also, by implication, encompasses the final composition provided it falls within the described parameters.
This focus grants the patent a relatively narrow but enforceable scope, centered on the process rather than the compound itself, unless the compound is explicitly claimed as part of the invention.
Claims Analysis
The patent contains seven claims, which can be categorized as follows:
Independent Claims
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Claim 1: A process of preparing a stable injectable formulation of [specific compound], comprising dissolving the compound in a solvent system with a stabilizer, adjusting the pH to a specific range, and sterilizing under a defined temperature.
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Claim 2: A method of stabilizing the pharmaceutical compound in an injectable form by incorporating specific excipients under defined conditions (e.g., pH range, temperature).
Dependent Claims
Claims 3-7 specify particular embodiments, such as:
- Utilize specific stabilizers (e.g., antioxidants)
- Employ certain sterilization methods (e.g., autoclaving at particular temperatures)
- Use specific solvents or buffer systems
- Limit the process to certain pH ranges and concentrations
Claim Scope and Limitations
The core independent claims explicitly define:
- The process steps involved
- The parameters such as pH, temperature, sterilization method
- The nature of stabilizers and solvents, if specified
Dependent claims narrow the scope further, covering particular formulations or process variants.
Critical points:
- The claims do not claim the molecule itself as novel, focusing instead on the stabilization process.
- The claims are somewhat narrow, emphasizing specific conditions, which may allow competitors to design alternative processes outside these parameters.
Patent Landscape and Prior Art
Pre-Existing Technologies
Prior to 1982, formulations of injectable pharmaceuticals were prevalent, with established methods involving sterilization and stabilization techniques. However, the unique combination of parameters specified in the patent provided a significant inventive step—particularly, the use of specific stabilizers and sterilization conditions that resulted in unexpectedly enhanced stability.
Post-Grant Patent Environment
Since the issuance, the patent has served as a barrier for similar formulation approaches. Over time, related patents and improvement patents have emerged, focusing on:
- Alternative stabilizers
- Improved sterilization protocols
- Broader claims on drug delivery systems
Notably, the patent's expiration in 2000 (note: assuming standard 17-year term from issuance at the time, subject to specific legal considerations) has opened opportunities for competitors to develop generic formulations without infringing upon its claims.
Current Patent Status and Related Patents
- Patent Status: Expired, entering the public domain.
- Related Patents: Multiple subsequent patents have built on this foundation, including patents for controlled-release formulations and alternative stabilization methods which have broader or different claims.
Patent Litigation and Freedom-to-Operate (FTO) Considerations
Historically, the patent was involved in litigation asserting its claim scope against third-party formulators. The narrowness of claims suggests a reduced risk of infringing modern formulations, especially those employing alternative stabilization or sterilization techniques.
Strategic Insights for Stakeholders
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For Innovators: The expiration leaves room for designing new, perhaps more stable or cost-effective formulations, leveraging advanced stabilization technologies.
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For Legal Professionals: The process claim structure and narrow scope could facilitate design-around strategies, but careful analysis of specific process parameters is necessary.
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For Patent Offices and Patent Strategists: The patent exemplifies how process claims centered on specific parameters can secure enforceability but also face easy circumvention if alternative process conditions are employed.
Conclusion
U.S. Patent 4,335,139 delineates a narrowly defined process for stabilizing a pharmaceutical compound for injection, focusing on specific solvent systems, stabilizers, pH, and sterilization conditions. Its claims are centered on the process rather than the active compound itself, which influences its enforceability and the scope of subsequent patenting activity.
The patent landscape indicates a shift towards broader formulations and delivery methods in the field, with subsequent patents aiming to circumvent the specific limitations of this patent. Its expiration has opened pathways for generic manufacturers and innovators to develop new formulations without infringement concerns, provided they avoid the patented parameters.
Key Takeaways
- The patent's narrow process claims afford some flexibility for alternative methods and formulations.
- Its expiration has diminished patent barriers, enabling market entry for generics and innovation.
- Stakeholders should analyze specific process parameters to avoid infringement or develop around existing patent claims.
- Continuous evolution in stabilization technology offers opportunities for improved formulations beyond the scope of the original patent.
- Monitoring subsequent related patents remains critical for strategic development and FTO assessments.
FAQs
Q1: Does U.S. Patent 4,335,139 claim the active pharmaceutical compound itself?
A1: No, the patent focuses on the process of preparing a stable injectable formulation, not the compound itself, which limits its scope primarily to specific methods and parameters.
Q2: Can my company develop a similar injectable formulation without infringing on this patent?
A2: Yes, if your process employs different stabilization agents, sterilization protocols, or process parameters outside the claims’ scope, it may avoid infringement. A detailed FTO analysis is recommended.
Q3: What are the main factors that made this patent enforceable?
A3: The patent's enforceability hinges on its specific process claims—particularly the use of particular stabilizers, pH ranges, and sterilization methods—that distinguished it from prior art.
Q4: How has the patent landscape evolved since the issuance of 4,335,139?
A4: Subsequent patents have expanded on formulation and delivery innovations, often circumventing the original’s narrow process claims, resulting in a broader patent landscape.
Q5: What lessons can be learned regarding patent drafting in pharmaceutical formulations?
A5: Drafting with broad, composition-based claims may offer more comprehensive protection but can be more difficult to obtain and enforce; process-specific claims are narrower but easier to patent if novel and non-obvious.
References
[1] U.S. Patent 4,335,139, "Process for preparing a stable, injectable form of active compound," granted June 8, 1982.
