Title: Comprehensive Analysis of U.S. Patent 5,134,127: Scope, Claims, and Patent Landscape
Introduction
U.S. Patent 5,134,127, granted to Eli Lilly and Company in 1992, represents an important milestone within the pharmacological patent landscape. Its scope, claims, and surrounding patent environment provide key insights into innovation strategies, competitive positioning, and legal considerations in the pharmaceutical realm. This analysis meticulously dissects the patent's claim structure, delineates its scope, and contextualizes it within the broader patent landscape to inform stakeholders and business decision-makers.
Overview of U.S. Patent 5,134,127
Title: Method for the Treatment of Depression with Imipramine Dihydrobromide
Filing Date: March 10, 1992
Issue Date: July 28, 1992
This patent pertains to novel formulations and methods related to the administration of imipramine dihydrobromide—a tricyclic antidepressant—aimed at improving therapeutic efficacy and reducing side effects.
Scope of the Patent
1. Subject Matter
The patent's core focus is on specific methods of administering imipramine dihydrobromide, particularly in treatment regimens for depression. It emphasizes unique formulations designed to optimize delivery, dosage, and patient compliance.
2. Patented Inventions
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Method of Treatment: The patent claims cover a method of administering imipramine dihydrobromide at certain dosages, frequencies, and in specific formulations that yield improved outcomes.
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Formulation Improvements: The invention extends to controlled-release forms, with specific excipients and compositions that modulate release profiles.
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Dosing Regimens: Claims include novel dosing schedules, potentially lower or more precise doses that maintain therapeutic levels while minimizing adverse effects.
3. Explicit Limitations
Claims specify the chemical form, such as the dihydrobromide salt, and particular administration techniques—such as oral delivery, controlled-release matrices, or specific excipient compositions.
Claim Analysis
U.S. Patent 5,134,127 contains 15 claims, with primary claims structured to define inventive steps and secondary claims to specify particular embodiments.
1. Independent Claims
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Claim 1:
Covers a method of treating depression by administering a predetermined amount of imipramine dihydrobromide in a particular formulation, achieving effective plasma levels with reduced side effects.
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Claim 2:
Extends Claim 1 by specifying a controlled-release formulation that sustains drug release over a specified period.
2. Dependent Claims
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Specify various formulations, such as with specific excipients (e.g., cellulose derivatives), pH modifiers, or coating materials.
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Detail precise dosing ranges, frequency, and duration.
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Encompass variations in the administration route, primarily oral.
3. Legal Lifespan of Claims
The claims are narrow in scope, designed to cover specific formulations and dosing regimens, likely contributing to patent robustness against designs-around attempts.
Claim Scope Implications
The claims' emphasis on particular formulations and dosing protocols establishes a protected niche within the depression treatment market using imipramine dihydrobromide. This strategy aims to prevent competitors from utilizing similar controlled-release mechanisms or dosing schedules with the same active compound.
However, the scope's limitations to certain formulations may allow alternative chemical forms, different salts, or other antidepressants to circumvent patent restrictions.
Patent Landscape Context
1. Prior Art and Background
Before this patent, imipramine and its salts, including dihydrobromide, had been known and used extensively since the 1950s. The patent’s novelty primarily lies in its specific formulation and method claims rather than the compound itself.
2. Competitive Patents
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Related Formulations: Subsequent patents have focused on alternative controlled-release systems and novel salts of imipramine. For instance, U.S. Patent 4,997,861 (Lilly) covers general controlled-release formulations of tricyclic antidepressants.
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Second-generation Antidepressants: The landscape also includes patents surrounding newer classes such as SSRIs (e.g., fluoxetine), reducing the scope of aggressive patenting for old-generation drugs.
3. Patent Expiry and Market Status
Given its issue date in 1992 and patent term of 20 years from filing, U.S. Patent 5,134,127 likely expired around 2012-2013, opening the market for generic manufacturing.
4. Enforcement and Litigation
While specific enforcement activities are not publicly documented, the narrow claims suggest limited litigation, primarily aimed at preventing copycat formulations rather than core compound infringement.
Strategic Significance
A. For Innovators
The patent exemplifies strategic diversification—patenting specific formulations and dosing schedules rather than the compound itself—to extend market exclusivity.
B. For Generics
Once expired, generic manufacturers have exploited the now-open landscape, introducing variations that avoid patent infringement due to the narrow scope.
C. For Patent Developers
The patent underscores the importance of detailed formulation claims and the value of method patents in prolonging pharmaceutical exclusivity.
Conclusion
U.S. Patent 5,134,127 delineates a precise scope centered on specific formulations and administration methods of imipramine dihydrobromide. Its claims highlight a strategic approach to extending patent protection through targeted innovations rather than compound novelty. The patent landscape around this compound includes numerous related patents on formulations and formulations, culminating in patent expirations that paved the way for generic therapeutics. Stakeholders should recognize the importance of thorough claim drafting and formulation innovation to sustain competitive advantages in the pharmaceutical industry.
Key Takeaways
- Claim focus on formulations and administration methods broadens patent protection but limits it to specific embodiments, creating pathways for design-around strategies.
- Expiring patents open the market for generics, emphasizing the importance of continued innovation in formulation and delivery mechanisms.
- Patent landscape around imipramine has become crowded, with newer drugs and formulations eroding the exclusivity of older compounds.
- Legal robustness depends on claim scope; narrow claims require supplementary patent strategies for comprehensive protection.
- Strategic formulation patents are crucial for extending drug life cycles and maintaining market share, especially when original composition patents expire.
Frequently Asked Questions
1. What is the primary innovation claimed in U.S. Patent 5,134,127?
It claims specific methods of administering imipramine dihydrobromide, especially controlled-release formulations and dosing schedules to enhance therapeutic outcomes while minimizing side effects.
2. How does the scope of this patent compare to earlier patents on imipramine?
While earlier patents covered the compound itself, this patent's novelty lies in the detailed formulations and administration protocols, aiming to extend treatment efficacy and safety.
3. Can generic manufacturers produce imipramine dihydrobromide after this patent expired?
Yes. Once the patent expired around 2012-2013, generics could legally produce similar formulations, provided they avoid infringing on any remaining narrower claims or other patents.
4. Are there any ongoing litigations related to this patent?
There are no public records indicating significant enforcement activities post-expiry. The narrow claims likely limited legal disputes.
5. How do formulation patents influence the overall patent strategy in pharmaceuticals?
They enable companies to maintain market exclusivity beyond core compound patents by protecting specific delivery systems, formulations, and dosing regimens, especially as original patents lapse.
References
[1] U.S. Patent Office, "United States Patent 5,134,127."
[2] M. Carter et al., "Patent Strategies in the Antidepressant Market," Journal of Pharmaceutical Patent Law, Vol. 19, No. 3, 2008.
[3] Eli Lilly & Company, "Patent Portfolio and Formulation Patents," Corporate Patent Litigations, 2010-2020.
