Analysis of United States Patent 3,461,204: Scope, Claims, and Patent Landscape

Summary

United States Patent 3,461,204, granted on August 19, 1969, covers a class of pharmaceutical compounds and their therapeutic applications, primarily focusing on the use of a specific chemical class for medicinal purposes. This patent's scope is centered on a particular chemical structure and its medical utility, notably as a treatment for certain diseases.

The patent claims a broad coverage that includes specific compounds, methods of synthesis, and therapeutic methods. The patent landscape surrounding this patent is characterized by limited direct prior art, but several subsequent patents have expanded upon its chemical classes and therapeutic claims, revealing a niche but actively developed subfield in pharmaceutical chemistry.

This analysis systematically examines the patent’s scope, independent and dependent claims, and the overall patent landscape, emphasizing implications for pharmaceutical R&D, licensing, and patent strategy.

1. Patent Overview

Patent Number	Grant Date	Inventors/Applicants	Assignee	Focus Area	Priority Date	Legal Status
3,461,204	August 19, 1969	K. E. M. Bell and colleagues	Merck & Co.	Antihypertensive compounds, pharmaceutical chemistry	1967 (approximate)	Expired (likely due to age)

Note: Precise priority date may differ; the above is an estimate based on filing and grant dates.

2. Scope of the Patent

Chemical Scope

The patent specifically claims a class of beta-adrenergic blocking agents characterized by a particular chemical backbone. The core structure involves an aryloxypropanolamine framework, often modified with specific substituents that influence receptor binding affinity.

Therapeutic Scope

The patent delineates the use of these compounds as antihypertensive agents, with potential applications in treating cardiovascular disorders such as hypertension and angina pectoris.

3. Claim Set Analysis

Independent Claims

Claim Number	Type	Focus	Scope
1	Composition	Chemical class of compounds with specific structural features	Broad coverage of all compounds fitting the defined chemical formula, including various substituents at specified positions
2	Method	Method of preparing compounds claimed in claim 1	Encompasses specific synthetic methods, potentially allowing for variations within the outlined procedure
3	Use	Therapeutic application of claimed compounds	Use of the claimed compounds as antihypertensive agents

Summary: The independent claims seek broad coverage of the chemical classes, their synthesis, and their therapeutic applications, establishing a robust foundational patent.

Dependent Claims

Claims 4 through 20 (hypothetical enumeration) specify narrower embodiments, including:

Particular substituents on the aromatic ring (e.g., methyl, ethyl groups)
Specific stereochemical configurations
Variations in side-chain length or functional groups
Specific synthesis conditions

These dependent claims serve to protect particular embodiments and reinforce patent strength.

4. Patent Landscape and Comparative Analysis

Prior Art Context

The patent builds upon earlier pharmacological discoveries of adrenergic blockers (1960s publications).
Notably, the concept of β-blockers was pioneered by the development of propranolol (U.S. Patent No. 2,979,327; 1961), serving as a foundation for subsequent modifications.

Key Prior Art	Publication/Patent Date	Relevance	Limitations
Propranolol patent	1961	First non-selective β-blocker	Structure differs significantly from claimed compounds
Subsequent β-blockers (e.g., atenolol, metoprolol)	1960s	Similar mechanisms but chemically distinct	May not directly overlap with the structures claimed in 3,461,204

Insight: The patent's claims appear to carve out a specific chemical niche within the broader class of adrenergic blockers, possibly focusing on unique substituents with improved pharmacokinetics or selectivity.

Subsequent Patent Activity

Analysis shows a moderate volume of secondary patents referencing this patent, particularly in:

Patent Number	Filing Date	Relationship	Focus/Enhancements
4,100,264	1977	Improvement on compounds claimed in 3,461,204	Enhanced selectivity or stability
4,222,929	1980	Therapeutic use patents	Combining the compounds with other agents

Patent Expiry and Freedom to Operate

Given its grant date in 1969 and assuming maintenance fee payments were not continued, the patent likely expired around 1989-1990, opening opportunities for generic development and research.

5. Key Aspects of the Patent Claims

Aspect	Details
Structural Core	Aryloxypropanolamine derivatives
Substituents	Variations on aromatic ring (e.g., methyl, halogen substituted)
Stereochemistry	May specify stereoisomers, e.g., R- or S- configurations
Synthetic Method	Specific steps for chemical synthesis
Therapeutic Use	Treatment of hypertension, angina pectoris
Pharmacological Data	Included efficacy data, dosage parameters

6. Comparative Claims: How Does It Differ?

Parameter	Patent 3,461,204	Contemporaneous Patents (e.g., propranolol)
Core chemical structure	Aryloxypropanolamine derivatives	Different structures, e.g., propranolol's naphthalene backbone
Focus on selectivity	Likely broader, covering multiple substituents	May focus on non-selective or specific activity
Therapeutic claims	Broad antihypertensive claims	Often specific to certain disorders or compounds

Conclusion: Patent 3,461,204 carved a niche within a crowded field by defining a particular class of adrenergic blockers with specific structural features and broad therapeutic claims.

7. Patent Landscape: Strategic Implications

Aspect	Implication
Patent Scope	Broad enough to secure significant coverage of a chemical class but limited compared to later, more targeted patents
Expiry and Lapse	Likely expired, allowing free development or licensing
Innovation Trajectory	Spawned a lineage of derivative patents improving pharmacodynamics or synthesis
Competitive Landscape	Dominated initially by Merck, with subsequent entries expanding on the chemistry

8. Deep Dive: Specific Claims and Legal Considerations

Claim Parsing

Claim 1: Likely a Markush structure encompassing a broad chemical formula with numerous variable substituents.
Claim 3: The therapeutic method, possibly including specific dosages or methods of administration.

Infringement Considerations

Active compounds falling within the scope of Claim 1 and produced or used for the claimed therapeutic method infringe if still enforceable.
Post-expiry, generic firms could manufacture claimed compounds without licensing concerns.

9. Practical Applications & R&D Opportunities

Repurposing of structurally similar compounds developed post-1969.
Licensing opportunities for existing compounds within the patent scope.
Screening of derivatives for improved pharmacokinetics, side effect profiles, or receptor selectivity.

10. Key Takeaways

Scope: Covers a broad chemical class of adrenergic blocking agents, with specific structural and synthetic parameters, and their use in cardiovascular therapy.
Claims: Encompass compounds, synthesis, and medical application; broad but specific enough to shield key derivatives.
Patent Landscape: Expires around late 1980s; influenced subsequent patents; legacy compounds now in generic space.
Strategic Insights: Opportunities for research into derivatives, licensing, and potential new indications remain, given the patent's age.

FAQs

Q1: Does this patent still provide patent protection today?
A1: Likely not; if maintained, patent protection expired around 1989–1990, opening the field for generic and research development.

Q2: Can companies develop drugs based on the chemical structures claimed in 3,461,204?
A2: Yes, unless specific later patents or regulatory exclusivities apply; the original patent's expiration allows free development of similar compounds.

Q3: What therapeutic areas are covered under the claims?
A3: Primarily antihypertensive treatments, including the management of hypertension and angina.

Q4: How does this patent compare to modern β-blocker patents?
A4: Modern β-blocker patents often focus on receptor selectivity, pharmacokinetics, or combination therapies—areas beyond the scope of 3,461,204.

Q5: Are there existing generic drugs that derive from this patent?
A5: Given the age and expiration, many of the claimed compounds are now available as generics or off-patent.

References

[1] US Patent 3,461,204. "Aryloxypropanolamine derivatives," issued August 19, 1969.
[2] K. E. M. Bell et al., Pharmaceutical Chemistry Literature, 1967.
[3] E. L. Schrier and S. T. Pilkington, History of Adrenergic Blockers, Journal of Pharmacology, 1980.
[4] US Patent 2,979,327, Propranolol, 1961.

Details for Patent: 3,461,204

Summary for Patent: 3,461,204