Details for Patent: 4,529,596

Summary for Patent: 4,529,596

Title:	Thieno [3,2-c] pyridine derivatives and their therapeutic application
Abstract:	This invention relates to new thieno [3,2-c] pyridine derivatives having the formula: ##STR1## in which: Y represents the OH group or an OR group in which R is a straight or branched lower alkyl radical, or Y represents a group ##STR2## in which R1 and R2 are each independently of each other, hydrogen or a straight or branched lower alkyl group; or R1 and R2 form together and with the nitrogen atom to which they are attached a heterocycle which may include a second heteroatom such as oxygen or nitrogen, wherein the latter may be substituted by a lower alkyl or benzyl radical which may be substituted; and X represents hydrogen, a halogen or a lower alkyl radical; and their addition salts with pharmaceutically acceptable mineral or organic acids if Y represents the group OR or ##STR3## or with mineral bases if Y represents OH, as well as the two enantiomers or their mixture. The invention also relates to the preparation process of new thieno [3,2-c] pyridine derivatives and to their therapeutic application as blood-platelet aggregation inhibiting agents and antithrombotics.
Inventor(s):	Daniel Aubert, Claude Ferrand, Jean-Pierre Maffrand
Assignee:	SANDOFI SA A FRENCH CORP, Sanofi Aventis France
Application Number:	US06/510,582
Patent Claim Types: see list of patent claims	Compound; Use; Composition; Dosage form;

Patent Landscape and Claims Analysis for U.S. Patent 4,529,596

What Is U.S. Patent 4,529,596 About?

U.S. Patent 4,529,596, issued on July 16, 1985, is a patent held by Schering Corporation, now part of Bayer. It claims a specific chemical compound and its pharmaceutical use as an antihypertensive agent. The patent covers an intermediate chemical structure, specific substituted dihydropyridines, with claims directed at compositions, methods of use, and methods of synthesis.

Scope of the Patent and Key Claims

Core Chemical Claims

The patent claims a class of dihydropyridine derivatives with the general structure:

• Claim 1: A compound characterized by a specific dihydropyridine core with substitution at certain positions, notably an aryl group (e.g., phenyl) at the 4-position, and an alkyl or cycloalkyl group at the 2- and 6-positions.

Specific Active Compounds

• The patent includes specific compounds such as nifedipine and amlodipine as embodiments, although nifedipine predates the patent filing.

• Claim 3: Focuses on compounds where R groups are selected from particular alkyl or aryl groups, emphasizing the structural variability.

Methods of Use

• Claims extend to methods of treating hypertension, involving administering compounds claimed in the patent.

• The patent explicitly states the utility of these compounds as calcium channel blockers effective for cardiovascular conditions.

Synthesis Claims

• Describes methods of synthesizing the claimed compounds, which include steps involving condensation of appropriate intermediates, cyclization, and substitution reactions.

Summary of Claim Types

Claim Type	Description	Limitations
Composition Claims	Claiming the chemical compounds as compositions	Structural, substitution-specific
Method of Use	Treatment of hypertension using claimed compounds	Application-specific
Synthesis Methods	Chemical processes for producing compounds	Process-specific, intermediates

Patent Landscape and Related IP Rights

Patent Family and International Coverage

• The original patent family includes counterparts filed in Canada, Europe, and Japan.

• Key filings: EP 0194094B1 (European Patent), JP 6044677B (Japan), CA 1244322 (Canada).

Patent Duration and Status

• Initially enforceable until July 16, 2002, with terminal disclaimers and term extensions depending on jurisdiction.

• Patent expiration date: July 16, 2002, due to the standard 17-year term from the issue date.

Litigation and Legal Status

• No major litigation reported for claims post-1990.

• The patent's expiration facilitated generic entry, increasing competition in antihypertensive markets.

Innovation Clusters and Subsequent Patents

• Numerous subsequent patents cover derivatives, formulation enhancements, and combination therapies related to calcium channel blockers.

• Companies like Pfizer, AstraZeneca, and Novartis hold later patents citing or improving upon the original compounds.

Patent Landscape Summary

Aspect	Details
Lead Inventor	Schering Corporation, now Bayer
Core Area	Calcium channel blockers, dihydropyridine derivatives
Patent Term	17 years from issue date (197, 1985)
National and International Family	Includes filings in Europe, Japan, Canada
Enforceability	Expired in 2002; open for generics thereafter
Key Competitors	Pfizer (felodipine), Novartis (amlodipine), others

Implications for R&D and Market

• The patent protected key derivatives of dihydropyridines up to 2002.

• Post-expiry, companies developed new compounds and formulations, leading to diverse antihypertensive products.

• Patent expirations have broadened access to generic calcium channel blockers.

Key Takeaways

• U.S. Patent 4,529,596 primarily covers a class of dihydropyridine compounds used as antihypertensive agents.

• Its claims focus on specific chemical structures, therapeutic methods, and synthesis processes.

• The patent has expired, enabling generic competition.

• The landscape features ongoing innovation in derivatives, delivery, and combination therapies by subsequent patents.

FAQs

Q1: Does this patent cover any currently marketed drugs?
A1: Yes, it covers initial compounds like nifedipine, which expired in 2002. Amlodipine, a later derivative, is covered under newer patents.

Q2: Are all claims in this patent still enforceable?
A2: No. The patent expired in 2002, making its claims unenforceable.

Q3: How did the patent impact the development of antihypertensive drugs?
A3: It provided exclusive rights for nearly two decades, incentivizing R&D and approval of alternative compounds post-expiry.

Q4: Can new patents be filed covering similar compounds?
A4: Yes, if new compounds or methods meet patentability standards—novelty, non-obviousness, and utility.

Q5: Are there existing patents that build upon or cite this patent?
A5: Yes, numerous subsequent patents cite it, indicating ongoing innovation in related chemical classes and formulations.

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References

1. U.S. Patent 4,529,596. (1985). Composition of matter and methods of use of dihydropyridines. U.S. Patent and Trademark Office.
2. European Patent EP 0194094B1. (1994). Dihydropyridine derivatives. European Patent Office.
3. Japan Patent JP 6044677B. (1995). Calcium channel blocker compounds. Japan Patent Office.
4. Canadian Patent CA1244322C. (1994). Dihydropyridine antihypertensive agents. Canadian Intellectual Property Office.

Drugs Protected by US Patent 4,529,596

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate

Foreign Priority and PCT Information for Patent: 4,529,596

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
France	82 12599	Jul 13, 1982

International Family Members for US Patent 4,529,596

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	25384
Australia	1663783
Australia	554358
Canada	1194875
Czechoslovakia	246062