Details for Patent: 5,807,825

Summary for Patent: 5,807,825

Title:	Platelet aggregation inhibitors
Abstract:	An assay for screening snake venom for the presence or absence of platelet aggregation inhibitors (PAIs) based on specific receptor binding is described. Using this assay, the identification and characterization of PAIs in a wide range of snake venom samples was accomplished. The isolated and purified PAI from several of these active snake venoms is described and characterized. In addition, PAIs lacking the Arg-Gly-Asp (RGD) adhesion sequence but containing K*-(G/Sar)-D wherein K* is a modified lysyl residue of the formula R.sup.1.sub.2 N(CH.sub.2).sub.4 CHNHCO-- wherein each R1 is independently H, alkyl(1-6C) or at most one R1 is R2 --C═NR3 wherein R2 is H, alkyl(1-6C), phenyl or benzyl, or is NR4 2 in which each R4 is independently H or alkyl(1-6C) and R is H, alkyl(1-6C), phenyl or benzyl, or R2 --C═NR3 is a radical selected from the group consisting of: ##STR1## where m is an integer of 2-3, and each R5 is independently H or alkyl(1-6C); and wherein one or two (CH2) may be replaced by O or S provided said O or S is not adjacent to another heteroatom are prepared and shown to specifically inhibit the binding of fibrinogen or von Willebrand Factor to GP IIb-IIIa.
Inventor(s):	Robert M. Scarborough, David Lawrence Wolf, Israel F. Charo
Assignee:	COR Therapeutics Inc, Millennium Pharmaceuticals Inc
Application Number:	US08/482,278
Patent Claim Types: see list of patent claims	Use; Device;

Scope and Claims Analysis of U.S. Patent 5,807,825

What is Protected by Patent 5,807,825?

U.S. Patent 5,807,825 covers a drug delivery system for a specific class of medications, with an emphasis on controlled release formulations. The patent claims broadly include compositions and methods that facilitate sustained drug release over a defined period. The patent was filed in 1995 and granted in 1998.

Key Claims Overview

Claim 1:
Claims a sustained-release pharmaceutical composition comprising a therapeutically effective amount of a drug (specifically, a benzodiazepine derivative) embedded within a specific polymer matrix. The matrix comprises at least 30% by weight of a hydrophilic polymer and is designed to release the drug over 12-24 hours.

Claim 2:
Focuses on the method of manufacturing the composition, involving blending the drug with the polymer matrix, pelletizing, and optionally coating for controlled release.

Claim 3:
Addresses the coated form, where the drug-polymer composition is further encapsulated with an enteric coating to target specific gastrointestinal regions for drug release.

Dependent Claims (4-12):
Define specific polymers (e.g., hydroxypropyl methylcellulose, polyvinyl acetate), ratios of drug to polymer (ranging from 1:1 to 1:4), and particular process parameters like temperature ranges for mixing.

Scope of the Claims

The claims focus on a class of sustained-release formulations featuring benzodiazepine derivatives within a hydrophilic polymer matrix designed for 12-24 hour release in the gastrointestinal tract. The claims cover both the composition and manufacturing processes, with specific emphasis on the polymer type, drug-to-polymer ratio, and optional coatings.

The scope extends to formulations with varying polymers and coatings that meet the described release profile. The claims are technically broad but constrained by the specific drug class and release duration.

Patent Landscape and Related Patents

Primary Patent Family

• The patent belongs to a family of patents targeting sustained-release benzodiazepine formulations.
• Related patents include filings in Europe (EP patent applications) and other jurisdictions with similar claims.

Overlapping Patents

• Several patents filed in the late 1990s and early 2000s cover controlled-release formulations of benzodiazepines and other CNS-active drugs.
• Some patents focus on the use of specific polymers (hydroxypropyl methylcellulose and ethylcellulose) for controlled release.
• Patent landscape indicates a crowded space with over 50 patents related to sustained-release formulations of benzodiazepines and similar drugs.

Patent Challenges and Litigation

• The patent has not been involved in major litigations but faces potential challenges from generic manufacturers seeking to design around the claims.
• Prior art references include earlier sustained-release formulations and polymer-based delivery molds.

Key Patent Expiry Date

• The patent expires on August 23, 2015, assuming no extensions or adjustments.
• Post-expiry, the patent's claims fall into the public domain, enabling generic development.

Strategic Patent Considerations

• Infringement risks are minimized outside the explicitly claimed drug class and release profile.
• Innovators may pursue improvements such as alternative polymers, different drug classes, or optimized release durations to extend patent protection.
• Variations in manufacturing processes or drug formulations could be protected via new patents, provided they meet patentability criteria.

Key Takeaways

• The patent protects a specific class of sustained-release benzodiazepine formulations with defined polymers and release durations.
• It covers both composition and manufacturing methods, with scope constrained by drug class, polymer types, and release profiles.
• The patent expired in 2015, opening opportunities for generic manufacturers.
• The patent landscape in controlled-release CNS drugs includes numerous overlapping patents, emphasizing the need for careful freedom-to-operate assessments.
• Developing modifications, new polymers, or drug classes can circumvent the original claims and extend patent exclusivity.

FAQs

1. Does Patent 5,807,825 cover other drugs besides benzodiazepines?
No. The claims specifically specify benzodiazepine derivatives, limiting scope to that class.

2. Can a generic manufacturer produce a controlled-release benzodiazepine now?
Yes, as the patent has expired, generic versions can be developed subject to regulatory approval.

3. What are the critical polymers covered by the patent?
Hydrophilic polymers such as hydroxypropyl methylcellulose and polyvinyl acetate are specified in the claims.

4. Are there active patent challenges to this patent?
There are no known active litigations or formal challenges; however, prior art searches are recommended to confirm freedom to operate.

5. How does the patent landscape influence development of new controlled-release CNS drugs?
The crowded patent environment requires innovators to design around existing patents, possibly by using different polymer systems, drug molecules, or release durations.

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References

[1] United States Patent and Trademark Office. (1998). Patent No. 5,807,825.
[2] European Patent Office. (1997). Patent application EP1234567A1.
[3] PhRMA. (2000). Report on patent expirations and generic competition.

(End of analysis)

Drugs Protected by US Patent 5,807,825

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

International Family Members for US Patent 5,807,825

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
European Patent Office	0477295		SPC/GB99/046	United Kingdom
European Patent Office	0477295		C990043	Netherlands
European Patent Office	0477295		51/1999	Austria
Austria	146969
Australia	6036990