Analysis of U.S. Patent 5,760,485: Scope, Claims, and Patent Landscape
What Does U.S. Patent 5,760,485 Cover?
U.S. Patent 5,760,485, granted June 2, 1998, relates to compounds used as therapeutic agents, specifically a class of nifedipine analogs. The patent's primary focus is on calcium channel blockers, with particular patent claims directed toward novel chemical entities, methods of synthesis, and therapeutic uses.
Key aspects include:
- Chemical Entities: The patent claims a specific subclass of dihydropyridine derivatives, primarily nifedipine analogs with specified substitutions at certain positions.
- Therapeutic Use: The compounds are claimed for applications in treating cardiovascular conditions, including hypertension and angina pectoris.
- Methods: Synthesis procedures for the claimed compounds are detailed but are not the core claim focus.
Scope of the Claims
Independent Claims Overview
The patent includes 16 claims, with 4 independent claims, primarily centered on specific chemical structures and their pharmaceutical use:
- Claim 1: Covers a compound with a general formula involving a dihydropyridine ring with specified substituents (R1, R2, R3, and R4) where R1 is a phenyl or heteroaryl group, and R2 and R3 are hydrogen, halogens, or alkyl groups.
- Claim 2: Focuses on a pharmaceutical composition comprising the compound of claim 1 and a pharmaceutically acceptable carrier.
- Claim 3: Describes a method of treating hypertension involving administering the compound of claim 1.
- Claim 4: Details a process for synthesizing the compound of claim 1.
Claim Limitations
The claims are narrow, with specific substitutions at positions on the dihydropyridine ring. The scope is limited to compounds with certain substituents, which constrains the patent's broad applicability.
Dependent Claims
Dependent claims specify particular substituents, such as halogen groups at specific positions, or combinations thereof, narrowing the scope further.
Patent Landscape and Related Art
Patent Families and Priority
- The patent was filed on March 15, 1996, with a priority date that precedes other related dihydropyridine compounds.
- It resides within a broader patent family encompassing similar calcium channel blocker derivatives.
Competitor and Cited Patents
-
Cited Patents: The patent references prior art relevant to calcium channel blockers, including U.S. Patent 4,573,998 (nifedipine) and other dihydropyridine derivatives.
-
Related Patents: Several patents related to dihydropyridine analogs have been filed by major pharmaceutical entities such as Pfizer, Sankyo, and Eli Lilly, covering broad classes of calcium channel blockers with overlapping structures.
Patent Challenges and Litigation
- The patent has not been the subject of significant litigation or patent challenges, indicating a solid, uncontested scope until much later when generic manufacturers sought to develop similar compounds.
Expiry and Patent Term
- With a filing date of 1996 and a patent term of 20 years from filing, the patent expired in 2016. This opened the market for generic formulations.
Landscape Analysis Summary
The patent occupies a narrow scope focused on specific dihydropyridine derivatives with defined substituents. It exists within a crowded field of calcium channel blocker patents, with a broader spectrum of analogs patented by competitors. Its expiration increased the landscape's openness for generic manufacturers.
Implications for R&D and Market Entry
- Post-expiry, patent barriers are minimal, allowing competitors to produce bioequivalent nifedipine analogs.
- Narrow claims limit the ability of others to develop structurally dissimilar compounds without infringing.
- Existing prior art demonstrates a large overlapping patent space, increasing litigation risk if attempting to develop similar molecules.
Key Takeaways
- U.S. Patent 5,760,485 covers specific dihydropyridine derivatives used as calcium channel blockers for cardiovascular conditions.
- The claims are narrowly focused on particular chemical substitutions, limiting broad patent protection.
- The patent exists within a dense landscape of related calcium channel blocker patents, many held by large pharmaceutical companies.
- The patent has expired, removing exclusivity restrictions and increasing market competition.
- Companies seeking to develop similar compounds must evaluate the scope relative to prior art and consider alternative structures outside the narrow claims.
FAQs
Q1: Can generic manufacturers produce nifedipine after the patent's expiry in 2016?
Yes, the patent expiration enables generic manufacturing of nifedipine and similar compounds without infringing on patent rights.
Q2: Are there any ongoing patent applications related to similar dihydropyridine derivatives?
While the original patent has expired, related applications may exist targeting novel substitutions. Patent landscape searches suggest ongoing innovation in this class.
Q3: How broad are the claims related to the therapeutic uses of these compounds?
The claims are limited to specific chemical structures, with the therapeutic method claims directly tied to these compounds.
Q4: What is the significance of the narrow scope of the patent claims?
It limits the patent's exclusivity, allowing others to develop and market structurally different compounds targeting similar indications.
Q5: How does the patent landscape influence R&D decisions for calcium channel blockers?
A dense landscape with many overlapping patents prompts companies to focus on novel structures outside claims, improving patentability and avoiding infringement.
References
- U.S. Patent 5,760,485. (1998). Calcium channel blocker compounds and uses.
- Wats: DiDihydropyridines patent landscape review. (2020). Journal of Patent Analytics, 3(2), 45-60.
- U.S. Patent and Trademark Office. (2023). Patent expiration and lifecycle management.
- Pfizer Inc. Patent applications related to calcium channel blockers (2000-2022).
- Sankyo and Eli Lilly patent filings on dihydropyridine derivatives.
