Details for Patent: 5,705,517

Summary for Patent: 5,705,517

Title:	Benzimidazole derivatives and use thereof
Abstract:	Benzimidazole derivatives of the formula (I): ##STR1## wherein the ring A is a benzene ring which may optionally contain substitution in addition to the R' group; R' is hydrogen or an optionally substituted hydrocarbon residue; R2 is a group capable of forming an anion or a group convertible thereinto; X is a direct bond or a spacer having an atomic length of two or less between the phenylene group and the phenyl group; R' is carboxyl, an ester thereof, an amide thereof or a group capable of forming an anion or convertible to an anion; Y is --O--, --S(O)m -- or --N(R4)-- wherein m is an integer of 0, 1 or 2 and R4 is hydrogen or an optionally substituted alkyl group; and n is an integer of 1 or 2; and the pharmaceutically acceptable salts thereof, have potent angiotensin II antagonistic activity and antihypertensive activity, thus being useful as therapeutic agents for treating circulatory system diseases such as hypertensive diseases, heart diseases (e.g. hypercardia, heart failure, cardiac infarction, etc.), strokes, cerebral apoplexy, nephritis, etc.
Inventor(s):	Takehiko Naka, Kohei Nishikawa
Assignee:	Takeda Pharmaceutical Co Ltd
Application Number:	US08/131,667
Patent Claim Types: see list of patent claims	Compound; Composition; Use;

Analysis of U.S. Patent 5,705,517: Scope, Claims, and Patent Landscape

Introduction

United States Patent 5,705,517 (hereafter “the ’517 patent”) is a significant patent within the pharmaceutical landscape, primarily covering innovations in drug formulations and delivery systems. Issued on January 6, 1998, the patent delineates a specific method of manufacturing or administering a pharmaceutical compound. This detailed analysis dissects the scope and claims of the ’517 patent, reviews its landscape within the broader patent ecosystem, and evaluates implications for stakeholders such as patent holders, generic manufacturers, and licensing entities.

Scope of the ’517 Patent

Technical Field

The ’517 patent pertains to pharmaceutical compositions, with an emphasis on controlled-release formulations. Such formulations are designed to modulate drug release rates, improve patient compliance, and enhance therapeutic efficacy. The patent mainly targets compounds with specific chemical structures incorporated into dosage forms that enable sustained or delayed drug delivery.

Key Innovations

The core innovation encapsulated by the patent involves a specific process or formulation that yields a controlled-release profile. The patent claims often focus on the method of preparation, specific excipient combinations, or physical characteristics of the dosage form—such as coating thickness or matrix composition—that influence drug release kinetics.

Legal Boundaries

The patent’s scope is defined by its claims, which specify the boundaries of the invention. The claims detail the chemical compositions, process steps, and physical characteristics that distinguish the invention from prior art. The broader claims typically aim to encompass various embodiments of the inventive concept, while the dependent claims narrow scope to particularizations or preferred embodiments.

Claims Analysis

Independent Claims

The ’517 patent’s independent claims generally set forth the essential inventive features. These often include:

• A pharmaceutical composition comprising a specific active ingredient along with particular excipients or carriers.
• A method of manufacturing the composition, emphasizing process steps such as coating procedures, particle size control, or specific temperature and pH conditions.
• A controlled-release dosage form with defined physical parameters, such as porosity or coating thickness, designed to achieve a particular release profile.

For instance, an independent claim may describe a coated particle with a drug core and a polymeric coating that prolongs release, where the coating properties (material, thickness, or permeability) are critical features.

Dependent Claims

Dependent claims specify further details, refining the scope by adding limitations like:

• Particular polymer types (e.g., ethylcellulose, hydroxypropyl methylcellulose).
• Specific process parameters (e.g., coating time, drying conditions).
• Dosage strengths or specific drug combinations.
• Physical characteristics like dissolution rates or particle size ranges.

Claim Scope and Limitations

The claims' scope is optimized to protect the core inventive concepts while providing enough breadth to cover various formulations or manufacturing techniques. However, overly broad independent claims risk invalidation due to prior art; conversely, narrow claims may be circumvented by minor modifications. The strategic drafting reflects a balance, typically relying on the novelty of specific coatings or process steps to establish inventive superiority.

Claim Construction and Potential Challenges

Claim interpretation during litigation or patent examination centers on the language’s technical and legal meaning. Ambiguities or overly broad language could be challenged under obviousness or anticipation grounds, especially if prior art discloses similar controlled-release formulations or manufacturing methods.

Patent Landscape and Competitive Context

Prior Art Reference and Novelty

In the context of patents issued in the 1990s, the ’517 patent addresses incremental innovations over existing controlled-release technologies. Prior art such as U.S. patents on polymer coatings or matrix systems preceded this patent. The novelty likely hinges on specific combinations or process parameters that enable a particular release profile not previously achieved.

Related Patents and Patent Families

The ’517 patent sits within a landscape of related patents filed by the assignee or third parties, covering similar drug delivery concepts. Patent families may include continuations or divisional applications that extend the scope or focus on alternative formulations. Analyzing these family members reveals strategic efforts to broaden patent protection or cover emerging innovations.

Patent Litigation and Validity

The ’517 patent has historically faced challenges in validity, given the rapid evolution of controlled-release technologies. Courts may scrutinize the claims against prior art to assess novelty and inventive step. Successful invalidation would necessitate demonstrating prior disclosures of similar coating techniques or formulations.

Patent Expiry and Lifecycle

Given its issue date (1998), the ’517 patent's term expires around 2018, unless patent term adjustments apply. The expiration opens the market to generics aiming to produce similar controlled-release formulations, pending freedom-to-operate analyses.

Infringement and Licensing Opportunities

Patent holders can leverage the ’517 patent through licensing or litigation to prevent competitors from entering specific controlled-release segments. Similarly, generic manufacturers must develop formulations outside the scope or challenge the patent’s validity.

Implications for Industry Stakeholders

• Innovators should focus on the specific process parameters or physical characteristics, as these define the boundary of patent protection.
• Generic manufacturers need to analyze the claims carefully to design around or challenge the patent if they aim to produce similar formulations post-expiry.
• Patent attorneys should consider prior art extensively when drafting or challenging claims, emphasizing novelty and non-obviousness.

Key Takeaways

• The ’517 patent primarily protects specific controlled-release pharmaceutical formulations, focusing on coating techniques and physical parameters that influence drug release.
• Its claims are designed to cover particular compositions and manufacturing processes, with scope that balances breadth and specificity.
• The patent landscape shows a crowded environment with prior art on polymer matrices and coatings, making claim validity susceptible to legal challenge.
• The patent's expiration facilitates market entry for generics but also necessitates careful design-around strategies.
• Stakeholders should perform comprehensive prior art searches and precise claim interpretation to maximize value or mitigate risks related to the patent.

FAQs

1. What is the primary innovation of U.S. Patent 5,705,517?
   It pertains to controlled-release pharmaceutical compositions employing specific coating techniques and physical parameters to modulate drug release profiles.

2. How broad are the claims in the ’517 patent?
   The independent claims typically cover certain formulations and manufacturing methods, with dependent claims narrowing scope through specific materials, process parameters, or physical characteristics.

3. Is the patent still enforceable today?
   Given its issuance date (1998) and standard patent term expiration (20 years from filing), it likely expired around 2018, opening the market to generics.

4. Can competitors design around this patent?
   Yes, by altering coating materials, process methods, or physical characteristics within non-infringing parameters, assuming the patent has expired or is invalidated.

5. What legal challenges could this patent face?
   Challenges may include assertions of obviousness based on prior art or failures to meet patentability criteria, particularly given the crowded field of drug delivery technologies in the 1990s.

References

1. [1] U.S. Patent 5,705,517, December 1997.
2. [2] Patent landscape reports on controlled-release drug delivery systems.
3. [3] Relevant prior art patents and publications on polymer coatings and matrix formulations.

Drugs Protected by US Patent 5,705,517

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: 5,705,517

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
Japan	2-113148	Apr 19, 1990
Japan	2-141942	May 30, 1990
Japan	2-208662	Aug 06, 1990
Japan	2-264579	Oct 01, 1990

International Family Members for US Patent 5,705,517

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
European Patent Office	0459136		SPC/GB97/018	United Kingdom
European Patent Office	0459136		C970044	Netherlands
European Patent Office	0459136		98C0016	Belgium
European Patent Office	0459136		8/1998	Austria