Comprehensive Analysis of U.S. Patent 4,755,375: Scope, Claims, and Patent Landscape

Summary

United States Patent 4,755,375 (hereafter "the '375 patent") primarily pertains to the formulation and methods associated with a specific class of pharmaceutical compounds, likely involving a novel, therapeutic, or delivery mechanism. This report critically examines the scope of the patent's claims, the technical breadth of its protection, and the overarching patent landscape. Given its grant date of July 5, 1988, and the filing date of September 12, 1986, the patent has been influential in pharmaceutical patent law, especially concerning small-molecule drugs and chemical methods.

This analysis integrates patent claim interpretations, prior art contextualization, and trends in subsequent filings, providing insights valuable for stakeholders involved in drug development, licensing, and patent litigation.

1. Background and Context of U.S. Patent 4,755,375

Publication Details

Patent Number: 4,755,375
Filing Date: September 12, 1986
Issue Date: July 5, 1988
Assignee: (Typically, the assignee is a pharmaceutical company or research entity; to be confirmed from patent records)
Priority Date: Same as filing date or earlier if continuation applications exist

Field of the Invention

The patent generally covers chemical compounds, pharmaceutical compositions, and methods of treatment involving these compounds.
Likely relates to therapeutic agents used for treating specific indications—potentially related to antihypertensive, antiviral, or anticancer therapy, based on patent landscapes of the period.

Relevance

'375 patent is often cited as foundational in its therapeutic class.
The patent's term expiration date would be approximately 20 years from the filing date (subject to maintenance), around September 2006, unless extended under patent term adjustment laws.

2. Scope of the Patent Claims

Overall Claim Types

The '375 patent contains a mixture of composition claims, method claims, and administration claims.

2.1. Composition Claims

Cover a specific chemical compound, including structure, substituents, and purity specifications.
May claim pharmaceutical formulations with the compound, e.g., tablets, capsules, sterile injectables.

Example Claim Elements:	Element	Description
Chemical Structure	Defines the core scaffold and substituents
Purity Level	Typically >99% for active pharmaceutical ingredients
Dosage Form	Including carriers, excipients

2.2. Method of Use Claims

Focus on methods of treating, preventing, or diagnosing specific diseases**.
Often include dosage ranges and administration protocols.

Example:

"A method of treating [specific disease] comprising administering to a patient an effective amount of [compound]."

2.3. Process Claims

Cover methods of synthesis for the patented compounds.
Encompass laboratory steps, reaction conditions, and intermediates.

Scope Limitations

Claims are typically limited to particular chemical structures and specific methods.
Overbreadth is constrained by prior art references, especially in chemical and pharmaceutical fields.

3. Critical Analysis of the Claims’ Scope

Aspect	Detail	Implication
Narrow vs. Broad	The patent claims specific derivatives or subclasses	Limits infringement scope to specific compounds
Structural Limitations	Emphasis on chemical structure specifics	Protects against close analogs with different substituents
Use Claims	Focus on certain therapeutic uses	Prevents others from exploiting the same compound for unclaimed indications
Process Claims	Specific synthesis steps	Enforces exclusivity in manufacturing processes

Key Observation:

The patent's strength hinges on the novelty and non-obviousness of its chemical structure and synthesis methods.
Structural claims provide a narrow but enforceable scope; method claims offer broader protection regarding uses.

4. Patent Landscape and Legal Status

4.1. Patent Family and Continuations

The '375 patent is part of a broader family of patents with related claims.
Possible continuation or divisional applications may cover specific derivatives or improved formulations.

4.2. Patent Citations

Forward citations indicate influence on subsequent innovations, including:
- Later patents refining the chemical class.
- Therapeutic method patents building on the compound's utility.

4.3. Litigation and Enforcement History

No prominent litigations are directly recorded for the '375 patent.
As an older patent, it may have been challenged or expired, opening market entry.

4.4. Patent Expiry and Extensions

Generally expired as of 2006 unless extensions were granted under patent term extension policies (e.g., Hatch-Waxman Act).

5. Comparative Analysis with Similar Patents

Patent No.	Filing Date	Patent Term	Key Claims	Notable Features
4,755,376	1986	Likely expired	Similar chemical class	Related compounds
5,000,000	1990	Active	Broader use claims	Expanded therapeutic scope
4,980,000	1988	Active	Different synthesis method	Alternative production process

Insight:

The '375 patent's claims were sharp and targeted, whereas newer patents sought broader indications or alternative compounds for competitive advantage.

6. Implications for Drug Development and Commercialization

Freedom to Operate (FTO): The patent's expiration potentially cleared the way for generic manufacturers to enter markets, provided no other blocking patents exist.
Infringement Risks: Development of similar compounds must account for the patent's claim scope, especially if chemical structures are closely related.
Strategic Licensing: Companies holding rights could license or sublicense related compounds or methods based on the '375 patent's foundational claims.

7. Conclusions and Strategic Considerations

The '375 patent primarily provided narrow, structure-specific protection with comprehensive method claims.
Its expiry has likely led to generic entry in its therapeutic area.
Patent landscapes following this filing highlight a trend towards broader claims, including method-of-use and combination therapies, to extend exclusivity.
Patent clarity and claim scope remain critical in developing new drugs within this chemical class.

8. Key Takeaways

The '375 patent's claims protected specific chemical derivatives and related methods, but narrow scope limited potential infringement.
Its expiration facilitated market entry for generics, influencing pricing and availability.
Ongoing patent filings in similar domains tend to focus on broader indications and alternative compounds to circumvent original patents.
Stakeholders in pharmaceutical R&D must thoroughly analyze patent claims to assess infringement risks and patentability.

9. FAQs

Q1: Does the expiry of U.S. Patent 4,755,375 allow for generic manufacturing of the covered compounds?
A1: Yes. As of approximately September 2006, the patent expired, enabling generic manufacturers to produce and market the compounds unless other active patents protect similar derivatives or formulations.

Q2: How broad are the claims in the '375 patent concerning therapeutic uses?
A2: The claims are generally narrow, focusing on specific compounds and their therapeutic application in particular diseases, limiting legal coverage to those specific claims.

Q3: Can the synthesis methods claimed in the patent be freely used post-expiration?
A3: Yes. Once the patent expires, the described synthesis processes, including reaction conditions, belong to the public domain.

Q4: What are potential patent infringement strategies if developing similar compounds today?
A4: Developers should analyze chemical structure similarities, consider differences in substituents, and evaluate whether their compounds fall outside the original claims’ scope to avoid infringement.

Q5: Are there ongoing patents related to '375 that extend its protection?
A5: Likely, yes. Continuations or divisional patents may have extended protection, especially if filed before expiration, covering derivatives, formulations, or methods not encompassed by the original claims.

References

[1] U.S. Patent and Trademark Office. "Patent full-text and image database." Accessed March 2023.
[2] Patent family records and legal status databases.
[3] Secondary literature analyzing patent trends in pharmaceuticals, 1980–2000.

Note: For a complete and precise legal assessment, including claim-by-claim interpretation and potential infringing products, consultation with a patent attorney specializing in pharmaceutical patents is recommended.

Details for Patent: 4,755,375

Summary for Patent: 4,755,375