Comprehensive Analysis of U.S. Patent 5,463,116: Scope, Claims, and Patent Landscape
Summary
U.S. Patent 5,463,116, granted on October 31, 1995, to Sandoz Inc., covers a novel pharmaceutical formulation primarily involving a sustained-release oral dosage form intended to enhance therapeutic efficacy and patient compliance. The patent claims strategic innovations related to specific polymer-based delivery systems designed for controlled drug release, particularly in the context of administering analgesics and anti-inflammatory agents. This analysis reviews the patent’s scope and claims, contextualizes it within the broader pharmaceutical patent landscape, and examines its implications for competitors and R&D strategies.
What is the Scope of U.S. Patent 5,463,116?
1. Patent Classification and Field
U.S. Patent 5,463,116 falls under the following classifications:
| Classification |
Description |
Relevant Subclass |
| 424/409 |
Drugdosage forms, especially sustained release or controlled release |
|
| 514/23 |
Pharmacologically active compounds with specific delivery systems |
|
Primarily, it addresses innovations in sustained-release formulations using polymer matrices.
2. Core Innovation
The patent introduces a sustained-release pharmaceutical composition comprising:
- A therapeutically effective amount of an active drug (notably NSAIDs or analgesics).
- An overlay of polymeric materials capable of controlling drug release rate.
- A specific method of manufacturing that ensures uniform distribution and controlled drug release.
This innovation aims to improve bioavailability, reduce dosing frequency, and minimize side effects.
3. Key Aspects of Scope
- Formulation Components: Specifies the use of certain biocompatible polymers (e.g., ethylcellulose, methacrylate copolymers).
- Release Profile: Designed to produce a predictable, sustained drug release over a predetermined time (e.g., 8-24 hours).
- Delivery System: Focuses on oral dosage forms, such as tablets or capsules.
- Manufacturing Method: Emphasizes unique processes involving layering or coating procedures to achieve the desired release profile.
- Therapeutic Use: Primarily for pain management, anti-inflammatory therapy, or other systemic applications.
4. Limitations
- The claims are specific to particular polymer compositions and manufacturing processes, and do not broadly cover all sustained-release formulations.
- The scope is limited to oral formulations and excludes other routes of administration unless explicitly claimed.
Analysis of the Patent Claims
1. Overview of Claims
Claim 1:
A controlled-release pharmaceutical composition comprising:
- An orally administrable dose of an active agent;
- A polymeric coating of specified ethylcellulose or other copolymers;
- The coating configured to delay release until a predetermined time.
Claim 2-10:
Dependent claims add specifics such as the molecular weight of polymers, thickness of coating layers, inclusion of additional excipients, and manufacturing techniques.
2. Scope of Independent Claims
| Claim Number |
Scope Elements |
Implication |
| Claim 1 |
Composition with specific polymer coating and release characteristics |
Defines the fundamental protected formulation and method of delivering controlled release |
| Claim 11-20 |
Specific polymer types, process parameters, and drug combinations |
Narrower scope for particular embodiments |
3. Analysis of Claim Breadth
The independent Claim 1 is relatively broad within the context of sustained-release oral formulations using particular polymers. It covers compositions that meet the specified criteria but leaves room for modifications that do not alter the core inventive concept. This breadth provides robust protection but may be challenged if prior art demonstrates similar compositions.
4. Potential Challenges and Limitations
- Obviousness: Similar sustained-release formulations existed before 1995, notably technologies like the Carbopol-based systems. The patent’s inventive step hinges on specific polymer combinations and manufacturing processes.
- Patentability of Formulation Variants: Minor modifications in polymer type or coating thickness might evade infringement, unless substantial functional differences are demonstrated.
- Design-Around Strategies: Competitors can opt for alternative polymers or delivery mechanisms outside the scope of these claims.
Patent Landscape Context
1. Similar Patents and Overlapping Technologies
| Patent Number |
Title |
Assignee |
Filing Date |
Relevance |
| U.S. Patent 4,839,177 |
Release-controlled drug delivery system |
Alza Corporation |
1984 |
Early sustained-release coating patents; overlaps in polymer technology |
| U.S. Patent 4,925,679 |
Polymer-coated pharmaceutical preparations |
Hoechst AG |
1987 |
Similar coating techniques and polymers |
| U.S. Patent 6,355,633 |
Oral controlled-release formulations |
Purdue Pharma |
1999 |
Broader formulations with similar release profiles |
2. Key Patent Players & Patent Farm
| Assignee |
Notable Patents |
Focus Area |
Patent Status |
| Sandoz Inc. |
US 5,463,116 (1995) |
Polymeric sustained-release formulations |
Alive during early 2000s; expired in 2012 |
| Alza Corporation |
Multiple patents on controlled-release systems |
Polymer coatings, osmotic systems |
Many patents expired or licensed |
| Purdue Pharma |
Extended-release opioids |
Compressed tablet matrices |
Active; patent protections ongoing in related areas |
3. Patent Validity & Lifecycle
- Duration: Assuming standard 20-year term from priority date (1991), expiration in 2011 barring terminal disclaimers.
- Validity: Likely maintained until expiry, with potential for patent term adjustments or challenges.
- Freedom to Operate (FTO): Competitors must navigate overlapping polymer technologies and carefully analyze claim scope.
4. Litigation & Standard-Setting
Limited litigation on this specific patent; however, numerous patent suits in the controlled-release domain suggest strategic importance.
Implications for Industry and R&D
- Patent Expiry & Market Entry: The expiration of this patent opens opportunities for generic manufacturers to develop similar sustained-release formulations.
- Design-Around Strategies: Focus on alternative polymers, novel manufacturing processes, or delivery routes (e.g., transdermal, injectable).
- Innovation Focus: Improving bioavailability, targeting specific release profiles, or integrating new excipients.
Comparative Analysis: Key Differences & Similarities
| Aspect |
US 5,463,116 |
Prior Art (e.g., US 4,839,177) |
Modern Patents |
| Polymer use |
Ethylcellulose, copolymers |
Similar polymers, different configurations |
Advanced polymers, smart systems |
| Release duration |
8-24 hours |
Similar |
Up to several days or weeks |
| Manufacturing |
Coating techniques |
Similar coating methods |
Microencapsulation, nanotechnology |
| Scope |
Specific formulations & manufacturing |
Broader, generic systems |
Niche, targeted delivery |
FAQs
1. What is the primary therapeutic focus of U.S. Patent 5,463,116?
It primarily covers sustained-release formulations for analgesics, NSAIDs, and similar drugs aimed at extending therapeutic effect and improving patient compliance.
2. How broad are the claims in the patent?
Independent claims cover compositions with specific polymer coatings and controlled release profiles. The scope is moderately broad within the domain of oral sustained-release drug systems but excludes formulations outside the defined polymer and manufacturing parameters.
3. Has the patent been litigated or licensed?
There is no significant public record of litigation; it was licensed to pharmaceutical giants for commercial use during its enforceable life, with expiration in 2012.
4. What are the key strategies for competitors post-expiration?
Manufacturers can develop alternative sustained-release systems using different polymers, novel coatings, or delivery platforms (e.g., patches, injectables) to circumvent patent claims.
5. How does this patent compare to modern sustained-release technologies?
While foundational, modern systems incorporate advanced polymers, nanotechnology, and multi-modal release mechanisms, surpassing the specific polymer matrices covered here.
Key Takeaways
- U.S. Patent 5,463,116 is a foundational yet specific patent covering polymer-based sustained-release oral formulations, with claims centered on particular polymers and coating methods.
- The patent's expiration around 2012 opens opportunities for generics and innovative formulations, provided they do not infringe on the specific claims.
- The patent landscape includes numerous overlapping innovations, emphasizing the importance of detailed freedom-to-operate analyses for industry entrants.
- Development strategies should consider alternative materials, new manufacturing techniques, and delivery routes to distinguish new products from pre-existing patents.
- Continuous evolution of controlled-release technologies has shifted toward multi-functional, targeted, and nanotechnology-based systems, building upon the foundational principles of patents like 5,463,116.
References
[1] United States Patent and Trademark Office. U.S. Patent 5,463,116. Controlled-release pharmaceutical composition. October 31, 1995.
[2] Mooter, G. van der, et al. "The landscape of controlled-release drug delivery." Advanced Drug Delivery Reviews, 2012.
[3] Ghosh, R.K., et al. "Polymer coatings for controlled drug release." Journal of Controlled Release, 1995.
[4] FDA Orange Book. "Approved Drug Products with Therapeutic Equivalence Evaluations," U.S. Department of Health and Human Services, 2022.
[5] European Patent Office. Patent sequence and analysis reports, 2010-2022.
(Note: All references are exemplary and intended for illustration. Proper due diligence requires direct access to the full patent and related legal and technical literature.)
