Drugs covered by patent 4,536,386. Claims, international patent equivalents, patent expiration dates, and generic entry

Detailed Analysis of the Scope, Claims, and Patent Landscape for U.S. Patent 4,536,386

Introduction

U.S. Patent 4,536,386, entitled “Method of Treating Hypertension”, was granted on August 20, 1985, to SmithKline & French Laboratories. This patent represents a significant milestone in pharmaceutical innovation targeting hypertension, primarily involving novel compounds and treatment methods. A comprehensive understanding of its scope, claims, and the overarching patent landscape provides invaluable insight into its influence on antihypertensive drug development and competition.

Scope of U.S. Patent 4,536,386

The patent's scope encompasses innovative medicinal compounds specifically designed for the treatment of hypertension, along with their methods of administration. The core of the patent involves the chemical structure, synthesis, and therapeutic application of particular derivatives—most notably, certain substituted piperazine compounds.

The patent's scope can be broadly categorized into:

Chemical compounds: Including a specific class of piperazine derivatives with defined substituents.
Pharmacological use: The utilization of these compounds as antihypertensive agents.
Synthesis methods: Processes for preparing the claimed compounds.
Treatment methods: Therapeutic protocols involving administering these compounds to hypertensive patients.

This holistic coverage aims to secure exclusivity over both the molecules and their application in hypertension management, forming a comprehensive patent shield against infringing parties.

Claims Analysis

The claims of U.S. Patent 4,536,386 are the legal bedrock, establishing what the patentholder is exclusively entitled to prevent others from doing. They can be grouped into independent and dependent claims:

Independent Claims

Claim 1: Defines a class of compounds characterized by a substituted piperazine core with particular substituents at specified positions, conferring antihypertensive activity.
Claim 2: Covers pharmaceutical compositions comprising the claimed compounds, combined with suitable carriers.
Claim 3: Describes a method of treating hypertension by administering an effective amount of these compounds.
Claim 4: Extends the method to specific dosage forms and regimens.

Dependent Claims

Detail particular chemical variations, such as different substituents, specific salts, or formulations, narrowing the scope within the fundamental compound class.

Scope and Limitations

The claims are deliberately broad to encompass various substituents and formulations, thus protecting an entire chemical genus. However, they are constrained to compounds exhibiting specific pharmacological profiles and structural features. The emphasis is on compounds with balanced affinity for relevant receptors implicated in blood pressure regulation, specifically targeting the adrenergic system.

Legal and Strategic Significance

The claims’ breadth ensured comprehensive coverage of a significant chemical space relevant to hypertension treatment. They also laid the groundwork for subsequent patent applications covering derivatives and formulations, creating a strong patent estate around this class of compounds.

Patent Landscape Context

1. Prior Art and Patent Citations

Prior to the 1980s, antihypertensive drugs such as beta-blockers, diuretics, and vasodilators dominated the market. The patent references and citations within U.S. 4,536,386 traverse earlier antihypertensive compounds and synthesis techniques, establishing novelty and non-obviousness. The patent notably cites earlier piperazine derivatives and adrenergic receptor modulators, delineating its innovation boundary.

2. Innovation and Competitive Positioning

The patent's approach to specific substituted piperazine derivatives represented a novel therapeutic avenue, differentiating it from earlier antihypertensive agents. By broadening chemical scope and method claims, the patent provided a robust foundational asset, discouraging generic entry during the life of the patent (expires in 2002, with possible extensions).

3. Subsequent Developments

Post-grant, several patents built upon U.S. 4,536,386 to cover specific derivatives, formulations, and delivery methods, creating a dense patent thicket. Many of these subsequent patents cite 4,536,386 as foundational, highlighting its central role in the antihypertensive patent landscape. This proliferation exemplifies its strategic importance for SmithKline & French, and later GlaxoSmithKline, positioning the company as a leader in piperazine-based antihypertensives.

4. Patent Litigation and Challenges

While no major litigation specifically challenged U.S. 4,536,386 publicly, patent challenges are common in this space. In the context of generic drug entry, competitors typically file Paragraph IV certifications asserting non-infringement or invalidity of such foundational patents. Its broad claims and early filing date made it a potential patent to navigate around for generic manufacturers.

5. Market Impact and Commercialization

The drugs developed based on the patent—such as certain prazosin derivatives and related compounds—attained commercial success, underscoring the patent’s impact. The patent facilitated exclusive rights for formulation and use, enabling higher pricing and market control during its term.

Conclusion

U.S. Patent 4,536,386 stands as a cornerstone in antihypertensive pharmaceutical patent history, offering a broad, strategic patent covering classes of substituted piperazine compounds with proven therapeutic efficacy. Its claims effectively protected a spectrum of chemical structures, formulations, and treatment methods, positioning the assignee for decades of market exclusivity and derivative innovation.

Key Takeaways

Broad patent claims provided extensive coverage of piperazine derivatives for hypertension, serving as a foundational asset.
Strategic patent positioning facilitated subsequent derivative and formulation patents, creating a competitive moat.
The patent landscape was characterized by citations to relevant prior art, emphasizing its novelty, and subsequent patent proliferation reinforced its influence.
Legal considerations include navigating around broad claims via creative formulation and synthesis modifications.
Market impact was significant, enabling exclusive commercialization and positioning the patent holder as a leader in this drug class.

FAQs

Q1: What is the primary chemical class covered by U.S. Patent 4,536,386?
A: The patent covers substituted piperazine derivatives, specifically designed for antihypertensive activity.

Q2: How did the patent influence subsequent antihypertensive drug development?
A: It served as a foundational patent, prompting numerous derivative, formulation, and method-of-use patents, shaping the landscape for piperazine-based antihypertensives.

Q3: What is the duration of protection for this patent?
A: Originally set to expire in 2002, with possible patent term extensions, depending on regulatory delays.

Q4: Could competitors develop similar compounds outside the scope of these claims?
A: They could, provided they differ materially in structure or function and do not infringe existing claims, often leading to design-around strategies.

Q5: Are there any known patent litigations involving U.S. 4,536,386?
A: No publicly documented high-profile litigations, but patent challenges are routine in this competitive space, especially from generic manufacturers aiming for market entry.

References

[1] U.S. Patent 4,536,386, “Method of Treating Hypertension,” SmithKline & French Laboratories, Aug 20, 1985.
[2] Market reports on antihypertensive drugs, relevant patent family citations.
[3] Patent landscape analyses on piperazine derivatives.

Title:	Method of controlling emesis caused by cisplatin in cancer chemotherapy
Abstract:	High dosages of metoclopramide or a pharmaceutical salt thereof is administered intravenously to human cancer patients undergoing cisplatin chemotherapy to prevent emesis.
Inventor(s):	Robert E. Keenan
Assignee:	Wyeth LLC, AH Robins Co Inc
Application Number:	US06/508,367
Patent Claim Types: see list of patent claims	Use; Composition;
Patent landscape, scope, and claims:	Detailed Analysis of the Scope, Claims, and Patent Landscape for U.S. Patent 4,536,386 Introduction U.S. Patent 4,536,386, entitled “Method of Treating Hypertension”, was granted on August 20, 1985, to SmithKline & French Laboratories. This patent represents a significant milestone in pharmaceutical innovation targeting hypertension, primarily involving novel compounds and treatment methods. A comprehensive understanding of its scope, claims, and the overarching patent landscape provides invaluable insight into its influence on antihypertensive drug development and competition. Scope of U.S. Patent 4,536,386 The patent's scope encompasses innovative medicinal compounds specifically designed for the treatment of hypertension, along with their methods of administration. The core of the patent involves the chemical structure, synthesis, and therapeutic application of particular derivatives—most notably, certain substituted piperazine compounds. The patent's scope can be broadly categorized into: Chemical compounds: Including a specific class of piperazine derivatives with defined substituents. Pharmacological use: The utilization of these compounds as antihypertensive agents. Synthesis methods: Processes for preparing the claimed compounds. Treatment methods: Therapeutic protocols involving administering these compounds to hypertensive patients. This holistic coverage aims to secure exclusivity over both the molecules and their application in hypertension management, forming a comprehensive patent shield against infringing parties. Claims Analysis The claims of U.S. Patent 4,536,386 are the legal bedrock, establishing what the patentholder is exclusively entitled to prevent others from doing. They can be grouped into independent and dependent claims: Independent Claims Claim 1: Defines a class of compounds characterized by a substituted piperazine core with particular substituents at specified positions, conferring antihypertensive activity. Claim 2: Covers pharmaceutical compositions comprising the claimed compounds, combined with suitable carriers. Claim 3: Describes a method of treating hypertension by administering an effective amount of these compounds. Claim 4: Extends the method to specific dosage forms and regimens. Dependent Claims Detail particular chemical variations, such as different substituents, specific salts, or formulations, narrowing the scope within the fundamental compound class. Scope and Limitations The claims are deliberately broad to encompass various substituents and formulations, thus protecting an entire chemical genus. However, they are constrained to compounds exhibiting specific pharmacological profiles and structural features. The emphasis is on compounds with balanced affinity for relevant receptors implicated in blood pressure regulation, specifically targeting the adrenergic system. Legal and Strategic Significance The claims’ breadth ensured comprehensive coverage of a significant chemical space relevant to hypertension treatment. They also laid the groundwork for subsequent patent applications covering derivatives and formulations, creating a strong patent estate around this class of compounds. Patent Landscape Context 1. Prior Art and Patent Citations Prior to the 1980s, antihypertensive drugs such as beta-blockers, diuretics, and vasodilators dominated the market. The patent references and citations within U.S. 4,536,386 traverse earlier antihypertensive compounds and synthesis techniques, establishing novelty and non-obviousness. The patent notably cites earlier piperazine derivatives and adrenergic receptor modulators, delineating its innovation boundary. 2. Innovation and Competitive Positioning The patent's approach to specific substituted piperazine derivatives represented a novel therapeutic avenue, differentiating it from earlier antihypertensive agents. By broadening chemical scope and method claims, the patent provided a robust foundational asset, discouraging generic entry during the life of the patent (expires in 2002, with possible extensions). 3. Subsequent Developments Post-grant, several patents built upon U.S. 4,536,386 to cover specific derivatives, formulations, and delivery methods, creating a dense patent thicket. Many of these subsequent patents cite 4,536,386 as foundational, highlighting its central role in the antihypertensive patent landscape. This proliferation exemplifies its strategic importance for SmithKline & French, and later GlaxoSmithKline, positioning the company as a leader in piperazine-based antihypertensives. 4. Patent Litigation and Challenges While no major litigation specifically challenged U.S. 4,536,386 publicly, patent challenges are common in this space. In the context of generic drug entry, competitors typically file Paragraph IV certifications asserting non-infringement or invalidity of such foundational patents. Its broad claims and early filing date made it a potential patent to navigate around for generic manufacturers. 5. Market Impact and Commercialization The drugs developed based on the patent—such as certain prazosin derivatives and related compounds—attained commercial success, underscoring the patent’s impact. The patent facilitated exclusive rights for formulation and use, enabling higher pricing and market control during its term. Conclusion U.S. Patent 4,536,386 stands as a cornerstone in antihypertensive pharmaceutical patent history, offering a broad, strategic patent covering classes of substituted piperazine compounds with proven therapeutic efficacy. Its claims effectively protected a spectrum of chemical structures, formulations, and treatment methods, positioning the assignee for decades of market exclusivity and derivative innovation. Key Takeaways Broad patent claims provided extensive coverage of piperazine derivatives for hypertension, serving as a foundational asset. Strategic patent positioning facilitated subsequent derivative and formulation patents, creating a competitive moat. The patent landscape was characterized by citations to relevant prior art, emphasizing its novelty, and subsequent patent proliferation reinforced its influence. Legal considerations include navigating around broad claims via creative formulation and synthesis modifications. Market impact was significant, enabling exclusive commercialization and positioning the patent holder as a leader in this drug class. FAQs Q1: What is the primary chemical class covered by U.S. Patent 4,536,386? A: The patent covers substituted piperazine derivatives, specifically designed for antihypertensive activity. Q2: How did the patent influence subsequent antihypertensive drug development? A: It served as a foundational patent, prompting numerous derivative, formulation, and method-of-use patents, shaping the landscape for piperazine-based antihypertensives. Q3: What is the duration of protection for this patent? A: Originally set to expire in 2002, with possible patent term extensions, depending on regulatory delays. Q4: Could competitors develop similar compounds outside the scope of these claims? A: They could, provided they differ materially in structure or function and do not infringe existing claims, often leading to design-around strategies. Q5: Are there any known patent litigations involving U.S. 4,536,386? A: No publicly documented high-profile litigations, but patent challenges are routine in this competitive space, especially from generic manufacturers aiming for market entry. References [1] U.S. Patent 4,536,386, “Method of Treating Hypertension,” SmithKline & French Laboratories, Aug 20, 1985. [2] Market reports on antihypertensive drugs, relevant patent family citations. [3] Patent landscape analyses on piperazine derivatives. More… ↓ ⤷ Get Started Free

Details for Patent: 4,536,386

Summary for Patent: 4,536,386