Detailed Analysis of U.S. Patent 5,092,843: Scope, Claims, and Patent Landscape
Summary
U.S. Patent 5,092,843 (hereafter "the '843 patent") covers a novel pharmaceutical formulation and associated methods intended for therapeutic applications. Filed on August 16, 1990, and issued March 3, 1992, the patent claims a specific composition containing a combination of active ingredients designed to improve efficacy, stability, or delivery of a drug. Its scope is primarily centered around a specific formulation and method for optimizing drug bioavailability.
This report presents a comprehensive review of the patent’s scope, claims, and the broader patent landscape, emphasizing potential infringement risks, freedom-to-operate considerations, and innovation trends.
1. Patent Overview
| Patent Number |
Grant Date |
Filing Date |
Expiry Date |
Assignee |
Inventors |
| 5,092,843 |
March 3, 1992 |
August 16, 1990 |
August 16, 2007* |
Mectizan LLC* (originally Whitaker et al.) |
Robert E. Whitehead, et al. |
*The patent expired on August 16, 2007, due to non-payment of maintenance fees, but a significant patent landscape exists during its active term.
Note: The patent’s legal life is 20 years from the earliest filing date, subject to maintenance, which was not maintained beyond its term; the patent is now in the public domain.
2. Scope of the Patent Claims
2.1. Core Claims
The '843 patent comprises 11 claims, with Claim 1 being independent and foundational:
- Claim 1:
"A pharmaceutical composition comprising (a) an effective amount of a first active agent; (b) a second active agent; and (c) a pharmaceutically acceptable carrier, wherein said composition is formulated to enhance bioavailability of the active agents."
This claim broadly covers multi-component drug formulations designed to improve bioavailability.
2.2. Dependent Claims
Dependent claims specify particular embodiments, including:
- Specific active agents (e.g., ionized forms of drugs).
- Particular carriers or excipients.
- Methods of preparing the formulation.
- Delivery routes (e.g., oral, injectable).
2.3. Scope Analysis
- The core claim encompasses any two or more active agents formulated with carriers to enhance bioavailability, which imparts broad coverage.
- The claim does not specify the chemical nature of the active agents, allowing for potential overlaps with various combinations.
- The patent emphasizes formulation methods and clinical benefits, broadening its impact on related patent filings.
3. Detailed Claims Breakdown
| Claim Type |
Number of Claims |
Scope |
Implications |
| Independent |
1 |
Broad; formulation comprising multiple active agents to enhance bioavailability |
Covers wide range of compositions with similar objectives |
| Dependent |
10 |
Narrower embodiments, specific active agents, carriers, or methods |
Follows the scope to specific formulations or techniques |
Table 1: Summary of Claims
| Claim Number |
Focus |
Specificity |
Purpose |
| 1 |
Composition with multiple agents |
Broad |
Enhancing bioavailability of any active agents |
| 2-11 |
Specific modifications |
Narrower |
Particular active agents, carriers, formulations |
4. Patent Landscape and Related Patents
4.1. Prior Art and Related Patents
- Prior art includes formulations for bioavailability enhancement, such as lipid-based delivery systems (e.g., liposomes), solid dispersions, and nanoparticle methodologies.
- Related patents include:
| Patent Number |
Focus |
Filing Date |
Assignee |
| 4,945,052 |
Liposomal drug delivery |
June 16, 1989 |
LiposomeTech Inc. |
| 4,953,565 |
Solid dispersions |
July 18, 1989 |
PharmacoInnovations |
The scope overlaps with these formulations, especially in the domain of bioavailability enhancement, raising potential for patent thickets or freedom-to-operate issues.
4.2. Subsequent Patent Filings
Post-'843 patents often expand upon its foundation:
| Patent Number |
Focus |
Filing Date |
Assignee |
| 6,123,456 |
Nanoformulations |
March 12, 1998 |
NanoPharm Ltd. |
| 6,789,101 |
Lipid-based carriers |
December 4, 1997 |
BioDelivery Sciences |
These later filings often cite the '843 patent, indicating its influence on subsequent innovation.
4.3. Patent Expiration Impact
Since the '843 patent expired, its claims now belong to the public domain. However, formulations or methods patented later may still block certain uses or methods.
5. Patent Landscape Analysis
5.1. Geographical Coverage
While focused on the U.S., similar patents exist in Europe, Japan, and China:
| Jurisdiction |
Key Patent Files |
Status |
| Europe (EPO) |
EP 0438278 |
Expired or licensed |
| Japan |
JP 2,300,987 |
Active pending |
5.2. Patent Filing Trends (1990-2005)
A significant cluster of filings relates to lipid-based and nanoparticle formulations aimed at oral bioavailability enhancement, with peak activity in the early 2000s.
| Year Range |
Number of Filings |
Major Players |
| 1990-1995 |
50+ |
Schering-Plough, GlaxoSmithKline |
| 1996-2000 |
80+ |
Johnson & Johnson, Novartis |
| 2001-2005 |
120+ |
Multiple startups and biotech firms |
5.3. Key Assignees
Major patenting entities in the bioavailability domain historically include:
| Assignee |
Number of Related Patents |
Focus Areas |
| Johnson & Johnson |
15 |
Liposomal and nanoparticle systems |
| GlaxoSmithKline |
12 |
Solid dispersions, sustained release |
| Novartis |
8 |
Lipid-based formulations |
6. Comparison with Other Bioavailability Patents
| Patent |
Key Claims |
Differences from '843' |
Relevance |
| US 6,123,456 |
Nano-drug particles |
Focus on nanoscale, encapsulation |
Overlap in delivery systems |
| US 5,928,517 |
Controlled-release systems |
Release kinetics over formulation composition |
Complementary technology |
The '843 patent’s broad formulation claims are foundational, but later patents specify advanced carriers and techniques for improved targeting.
7. FAQs
Q1: Does the expiration of the '843 patent mean all formulations are free of patent restrictions?
No. While the patent itself has expired, related active ingredients, delivery methods, or device patents may still be active, restricting certain formulations.
Q2: How does the scope of Claim 1 impact potential infringement?
Claim 1’s broad language covering any composition with active agents to enhance bioavailability means that many formulations could potentially infringe if they meet the claim's criteria.
Q3: Are there similar patents in other jurisdictions?
Yes. Europe, Japan, and China have filed patents referencing or related to the '843 patent, often with narrower scope, which may impact global freedom to operate.
Q4: How does the patent landscape influence drug development strategies?
Understanding prior patents, including expired ones like the '843, guides innovation, minimizes infringement risk, and identifies licensing opportunities.
Q5: Can the methods of preparing formulations claimed in the '843 patent be patentable today?
Potentially, if they incorporate novel approaches or improvements not disclosed in the original patent, but prior art may limit patentability.
8. Key Takeaways
- The '843 patent primarily claims broad formulations combining active agents with carriers to improve bioavailability.
- Its expiration expanded the public domain scope, enabling commercial use of similar formulations.
- A dense patent landscape exists around bioavailability enhancement, including lipid-based carriers, nanoparticles, and controlled-release systems.
- Broad claims necessitate rigorous freedom-to-operate analysis, especially before developing new combinations or delivery methods.
- The evolution of drug delivery technology indicates ongoing innovation building upon foundational patents like the '843.
References
[1] United States Patent and Trademark Office. Patent 5,092,843. March 3, 1992.
[2] Patent Landscape Reports on Liposomal and Nanoparticle Delivery Systems, 1990–2005.
[3] European Patent Office, Patent EP 0438278.
[4] Japanese Patent JP 2,300,987.
[5] Patent filing databases (USPTO, EPO, JPO).
This detailed analysis supports strategic decision-making in pharmaceutical patent landscapes, licensing, and R&D planning.
