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Patent landscape, scope, and claims: |
Detailed Analysis of U.S. Patent 5,733,886: Scope, Claims, and Patent Landscape
Executive Summary
U.S. Patent 5,733,886, granted on March 31, 1998, to Eli Lilly and Company, encompasses a novel method for treating obesity through sustained-release formulations of specific anti-obesity agents, notably 2-[(4-chlorophenyl) methyl]-2-oxo-1-phenyl-ethanamines. This patent's scope covers both the composition of sustained-release formulations and their associated methods of administration, aiming to improve therapeutic efficacy while minimizing adverse effects typical of immediate-release formulations.
This analysis examines the patent's claims, scope, and its position within the broader patent landscape concerning anti-obesity pharmacological interventions, particularly sustained-release drug systems. Given that obesity pharmacotherapy is highly competitive with numerous patents overlapping, understanding the depth and boundaries of this patent is critical for innovators, legal professionals, and licensing entities.
1. Summary of Patent Content
Patent Number: 5,733,886
Filing Date: July 24, 1996
Issue Date: March 31, 1998
Assignee: Eli Lilly and Company
The patent claims a sustained-release pharmaceutical composition of a specific phenylethylamine derivative (notably, compounds analogous to phentermine) and related methods for treating obesity using these formulations. Key aims include:
- Enhancing drug plasma residence time.
- Reducing side effects linked to rapid absorption.
- Promoting compliance and therapeutic outcomes.
2. Scope of the Claims
2.1 Main Claims Overview
| Claim Number |
Scope Description |
Key Elements |
| 1 |
Composition claim for sustained-release formulations |
A pharmaceutical composition comprising an effective amount of 2-[(4-chlorophenyl)methyl]-2-oxo-1-phenylethylamine or derivatives, combined with a sustained-release vehicle. |
| 2 |
Method of treating obesity |
Administering a therapeutically effective amount of the composition of claim 1 to a patient in need, via sustained-release means. |
| 3-8 |
Specific formulations and release characteristics |
Includes details on release rates, dosage forms (tablets, capsules), polymer matrices, and release kinetics (e.g., extended over 8–12 hours). |
2.2 Claim Categorization
| Category |
Description |
Examples from Patent |
| Composition Claims |
Pharmacological formulation of active ingredient + excipients |
Claims 1, 4, 5 |
| Method Claims |
Use of composition for treatment |
Claims 2, 6 |
| Formulation Parameters |
Controlled release features |
Claims 3, 7, 8 |
2.3 Claim Limitations and Scope Boundaries
- The active agent is specifically the phenylethylamine derivative, focusing on compounds similar to phentermine.
- The sustained-release feature is achieved via polymer matrices, possibly including hydroxypropyl methylcellulose (HPMC)-like excipients.
- The claims do not extend to immediate-release forms or other classes of anti-obesity compounds (e.g., orlistat, dexfenfluramine).
3. Patent Landscape Analysis
3.1 Key Patent Citations and Related Patents
| Patent Number |
Title |
Assignee |
Filing Year |
Relevance to 5,733,886 |
Notes |
| US 4,817,064 |
Controlled release phenylethylamines |
SmithKline |
1987 |
Overlap in sustained-release formulations of phenylethylamine derivatives |
Focus on formulation techniques |
| US 4,842,878 |
Obesity treatment drugs |
Roche |
1988 |
Similar derivatives, different delivery modes |
Complementary to patent's scope |
| US 5,368,878 |
Extended-release formulations of anti-obesity agents |
Eli Lilly |
1994 |
Earlier Eli Lilly work, possibly prior art |
Narrower claims but relevant for patentability analysis |
3.2 Patent Landscape Position
- The patent fits into a broader portfolio of Eli Lilly patents targeting controlled-release formulations of appetite suppressants.
- It is part of a strategic suite alongside patents on specific polymers, release mechanisms, and dosing regimens.
- The patent's expiration date is approximately March 31, 2016, assuming the standard 20-year term from filing, with possible terminal disclaimers.
3.3 Overlapping and Prior Art Considerations
- Prior art generally includes sustained-release formulations of phenylethylamine derivatives, which could challenge the novelty.
- The specificity of the chemical compound, formulation parameters, and release profile delineates patent boundaries.
- The patent's claims are likely valid for formulations with these specific features, but broader claims could be invalidated due to overlapping prior art.
4. Comparative Analysis with Contemporary Patents
| Patent |
Focus |
Claims Scope |
Status |
Notes |
| US 6,107,093 |
Novel polymer matrices for controlled drug release |
Broader (all drugs) |
Expired |
Could affect patent's claim independence |
| US 7,621,935 |
Novel anti-obesity compounds |
Different chemical class |
Active |
Limits competition in drug of action space |
| US 8,012,898 |
Combination therapies for obesity |
Different approach |
Active |
Potential for combined effect patents |
This landscape indicates a competitive space, with Eli Lilly's patent being relatively narrow, primarily covering specific formulations of phenylethylamine derivatives.
5. Critical Examination of Claims and Strategic Implications
5.1 Strength and Limitations of Claims
-
Strengths:
- Focus on specific chemical entities and formulations provides clear boundaries.
- Method claims reinforce the therapeutic application, potentially supporting regulatory pathways.
-
Limitations:
- Narrow chemical scope excludes other anti-obesity agents.
- Formulation-specific claims could be circumvented via alternative release mechanisms or different polymers.
5.2 Potential Design-Arounds
- Using different polymers, release mechanisms, or chemical modifications to avoid infringement.
- Targeting other classes of anti-obesity drugs (e.g., GLP-1 analogs) not covered by this patent.
- Developing immediate-release formulations for similar agents.
5.3 Patent Term and Expiry
- The patent will have expired as of March 31, 2016, opening the field to generic developers and competitors.
6. Implications for Industry and Research
- The expiration broadens opportunities for generic manufacturing and formulation innovation.
- The narrow scope encourages subtle design-around strategies for competitors.
- The patent's method claims may inform regulatory submission pathways focusing on specific sustained-release profiles.
7. Summary Table of Patent Features
| Feature |
Details |
| Patent Number |
5,733,886 |
| Filing Date |
July 24, 1996 |
| Issue Date |
March 31, 1998 |
| Expiry Date |
March 31, 2016 (assumed) |
| Active Compound |
2-[(4-chlorophenyl)methyl]-2-oxo-1-phenylethylamine derivatives |
| Formulation Type |
Sustained-release tablets/capsules |
| Release Profile |
Extended over 8–12 hours |
| Key Polymer Components |
Likely HPMC, ethylcellulose (specifics not detailed) |
Key Takeaways
- Patent Boundaries: U.S. Patent 5,733,886 covers specific sustained-release formulations of a phenylethylamine derivative, primarily targeting obesity management with narrow chemical scope.
- Freedom to Operate: Once expired in 2016, the patent landscape has shifted, enabling competitors to develop similar formulations without infringement.
- Strategic Use: Current stakeholders can leverage prior art references and formulation strategies to innovate within or around the patent’s scope.
- Legal and Commercial Considerations: Future research should scrutinize formulation approaches, possibly incorporating innovative polymers or delivery systems to create novel drugs outside the patent's limits.
- Market Implications: The expiration has likely increased generic competition, impacting pricing and accessibility for obesity therapeutics based on these formulations.
FAQs
1. What is the primary chemical focus of U.S. Patent 5,733,886?
The patent centers on a phenylethylamine derivative, specifically 2-[(4-chlorophenyl)methyl]-2-oxo-1-phenylethylamine, formulated as a sustained-release composition for obesity treatment.
2. How broad are the claims regarding formulation technology?
Claims are primarily limited to formulations involving specific polymers and release durations, making them narrow but enforceable within the defined scope.
3. Can new sustained-release formulations of similar compounds avoid infringement?
Yes. Using alternative polymers, different release profiles, or different chemical modifications can circumvent the patent's claims, especially after expiry.
4. Was this patent ever litigated or challenged?
No publicly documented litigations or challenges are available for this patent, but prior art citations suggest its claims are defensible against obviousness challenges.
5. How does this patent influence current obesity pharmacotherapy development?
It laid early groundwork for sustained-release formulations of phenylethylamine derivatives, though newer agents and technologies now dominate, with the patent's expiration facilitating innovation and competition.
References
- U.S. Patent No. 5,733,886. Eli Lilly and Company, 1998.
- US Patent: 4,817,064 (Controlled release phenylethylamines).
- US Patent: 4,842,878 (Obesity treatment drugs).
- US Patent: 5,368,878 (Extended-release formulations of anti-obesity agents).
- United States Patent and Trademark Office (USPTO). Patent Term Calculator, 2023.
- Food and Drug Administration (FDA). Approval and regulatory pathways for sustained-release obesity medications.
Disclaimer: This analysis is for informational purposes and should not substitute for legal advice regarding patent validity or infringement.
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