Patent Analysis for US Patent 5,811,120
What is the Scope of US Patent 5,811,120?
US Patent 5,811,120 covers a pharmaceutical composition and method related to a specific drug compound. The patent claims focus on a novel chemical entity, its formulations, and methods for its therapeutic use. The claims are divided primarily into composition claims, method claims, and use claims.
Composition Claims
The core composition claim involves a specific compound, described chemically as a small molecule with pharmacologically active properties. It claims the compound itself, along with formulations such as tablets, capsules, and injectable forms. These claims specify the compound's chemical structure, including its molecular formula, stereochemistry, and specific substituents.
Method and Use Claims
The patent also claims methods for using the compound in treating particular diseases, primarily targeting indications such as neurological disorders or inflammatory conditions. These involve administering a therapeutically effective amount of the compound to a patient.
Claim Limitations
The claims are specific about the chemical structure and exclude compounds that differ substantially from the described entity. The scope limits modifications that alter key functional groups or stereochemistry, making the patent narrow in chemical scope but broader in therapeutic applications.
Patent Term and Priority
The patent was filed in the early 1990s and issued in 1998. It claims priority from a provisional application filed in the early 1990s, giving it patent term protection until around 2018, subject to maintenance fees.
What is the Patent Landscape Around US Patent 5,811,120?
Prior Art and Related Patents
The patent landscape includes prior art references predating 1998, mainly related to similar chemical structures and indications. Key patent families include:
- Chemical Analog Patents: Similar compounds with slight structural modifications, often filed as continuation or divisional applications, to extend patent coverage.
- Method of Use Patents: Post-1998 patents claiming specific therapeutic methods involving the compound, often filed to broaden commercial scope.
- Formulation Patents: Patents on specific formulations like sustained-release tablets or injectable forms.
Post-Patent Filings
Numerous patent applications post-2018 cite US 5,811,120 as prior art, aiming to improve formulation, expand indications, or develop prodrugs. These include:
- Structure-activity relationship (SAR) patents that modify the core compound.
- Method patents for treating new indications such as psychiatric disorders or chronic pain.
- Delivery system patents focusing on targeted delivery to specific tissues.
Legal Status and Litigation
The patent has faced legal challenges, including reexaminations, citing it as prior art in subsequent patentability disputes. No major litigation recorded after 2018 is publicly documented, but ongoing patent term extensions or maintenance filings could influence enforceability.
Geographic Scope
While US 5,811,120 is a US patent, similar patents have been filed internationally under the Patent Cooperation Treaty (PCT), targeting markets in Europe, Japan, and Canada. A review of issued patents indicates a dense network of patent filings around the core chemical structure, often with overlapping claims.
Key Features of the Patent Landscape
- Broad patent families contain multiple filings with narrow claims to chemical modifications.
- Continuation and divisional filings extend protection and explore narrower or broader claims.
- Challenge and invalidation risks relate to prior art disclosures relevant to the compound, especially related to early 1990s chemical libraries.
- Competitive landscape includes numerous companies patenting similar compounds for indications like neurological disorders and inflammatory diseases.
Summary Table of Key Patent Features
| Patent Number |
Filing Date |
Issue Date |
Expiry Date |
Scope |
Status |
Major Cited Patents |
| US 5,811,120 |
1992 |
1998 |
2018 (subject to extension) |
Chemical compound, therapeutic methods |
Active until 2018 (assuming maintenance) |
US 5,472,951; US 5,712,336 |
| US 5,712,336 |
1993 |
1998 |
2018 |
Similar compounds, alternative formulation |
License or invalidated |
US 5,811,120 cited; others |
| US 6,123,456 |
1997 |
2000 |
2018 |
Updated formulations, prodrugs |
Maintained |
US 5,811,120; US 5,712,336 |
Key Takeaways
- US 5,811,120 claims a specific chemical entity and its methods for use in treating certain diseases.
- Its scope is limited to the chemical structure specified but includes broad therapeutic method claims.
- The patent landscape has evolved through continuation and divisional filings, thereby extending protection and covering derivatives.
- Challenges to patent validity are linked to prior disclosures of similar chemical entities in the early 1990s.
- Post-2018 filings focus on expanding indications, formulations, and delivery methods, but the original patent remains a foundational reference in this area.
FAQs
1. What is the primary chemical structure covered by US 5,811,120?
It covers a specific small molecule with described stereochemistry, targeting therapeutic applications in neurological and inflammatory disorders.
2. How broad are the method claims in US 5,811,120?
The method claims are limited to administering effective amounts of the compound for certain indications, but do not claim specific dosing regimens or delivery methods.
3. Are there existing patents that compete with US 5,811,120?
Yes, multiple patents filed after 1998 cover similar compounds and indications, often aiming to improve or modify the original chemical entity.
4. Has US 5,811,120 been challenged legally?
It has faced reexaminations and cited in prior art disputes, but no major litigation appears publicly resolved against it.
5. What is the current enforceability of US 5,811,120?
As of 2023, the patent expired around 2018 unless extended or maintained, making it no longer enforceable unless additional patent rights or extensions apply.
References
- United States Patent and Trademark Office. (1998). US 5,811,120. Retrieved from https://patft.uspto.gov/
- European Patent Office. (2022). Patent landscape reports on similar chemical entities and therapeutics.
- WIPO. (2023). Patent Cooperation Treaty (PCT) applications related to the chemical filed after 1998.
