United States Patent 5,990,176: A Detailed Analysis of Scope, Claims, and Patent Landscape
Introduction
The United States Patent 5,990,176, issued to Abbott Laboratories, is a significant patent in the field of pharmaceuticals, particularly concerning the stabilization and storage of the inhalational anesthetic sevoflurane. This article delves into the scope, claims, and the broader patent landscape surrounding this patent.
Background of the Patent
The patent, titled "Stabilized Sevoflurane Compositions," was granted on November 23, 1999. It addresses the issue of sevoflurane degradation, which is crucial for maintaining the efficacy and safety of the anesthetic[1][5].
Scope of the Patent
The patent's scope is centered around methods and compositions for stabilizing sevoflurane. Here are the key aspects:
Stabilization Method
The patent teaches that to prevent the degradation of sevoflurane, an effective stabilizing amount of a Lewis acid inhibitor must be added. This is critical because sevoflurane can degrade over time, leading to the formation of potentially harmful compounds[1].
Container Specifications
The patent specifies that the sevoflurane can be stored in containers made of materials such as glass, plastic, or stainless steel. However, the interior of these containers must be treated to prevent degradation. For example, metal containers can be coated with a layer that includes a Lewis acid inhibitor[2].
Claims of the Patent
The patent includes several claims that define the scope of the invention:
Claim 1: Composition
The first claim describes a stabilized composition of sevoflurane that includes a Lewis acid inhibitor in an effective stabilizing amount. This claim is broad and encompasses various formulations where the inhibitor prevents degradation[1].
Claim 2: Container Coating
Subsequent claims detail methods for storing sevoflurane in containers with interior walls coated with a Lewis acid inhibitor. This is particularly relevant for metal containers, such as aluminum, which are commonly used in the pharmaceutical industry[1].
Claim 3: Concentration of Inhibitor
Another claim specifies the use of at least 150 parts per million of a Lewis acid inhibitor to prevent degradation of sevoflurane. This precise concentration is crucial for ensuring the stability of the anesthetic[1].
Patent Landscape and Related Patents
The patent landscape around U.S. Patent 5,990,176 is complex and involves several related patents and applications:
Related Patents
- U.S. Patent No. 6,008,273: This patent describes an epoxy resin for coating the inside of metal containers, which can be relevant for storing sevoflurane. However, it is not specifically focused on anesthetic stabilization[2].
- U.S. Patent No. 6,074,668: This patent covers the storage of sevoflurane in plastic containers, which is another aspect of the broader patent landscape related to anesthetic storage[1].
Litigation and Validity
The validity of U.S. Patent 5,990,176 has been challenged in court. In a notable case, the Federal Circuit invalidated the patent, finding that the claims were not valid due to prior art and other issues[5].
Impact on Generic Drug Manufacturers
The patent has significant implications for generic drug manufacturers. For instance, in the case of Abbott Laboratories v. Baxter Healthcare Corp., the court considered whether Baxter's generic sevoflurane product would infringe on Abbott's patents. The approval of Baxter's ANDA (Abbreviated New Drug Application) and the use of aluminum containers lined with an epoxyphenolic liner were central to the dispute[1].
International Patent Considerations
The stabilization of sevoflurane is a global concern, and similar patents and applications exist in other jurisdictions. The World Intellectual Property Organization (WIPO) and other international patent offices provide databases and tools for searching and comparing patent applications across different countries[4].
Key Takeaways
- Stabilization Method: The patent emphasizes the use of Lewis acid inhibitors to prevent sevoflurane degradation.
- Container Specifications: Containers must be treated with a Lewis acid inhibitor to ensure stability.
- Claims: The patent includes claims related to the composition, container coating, and concentration of the inhibitor.
- Patent Landscape: The landscape includes related patents on container coatings and storage methods.
- Litigation: The patent's validity has been challenged and invalidated by the Federal Circuit.
FAQs
What is the main purpose of U.S. Patent 5,990,176?
The main purpose is to describe methods and compositions for stabilizing sevoflurane using Lewis acid inhibitors.
What types of containers are specified in the patent?
Containers made of glass, plastic, or stainless steel are specified, with a focus on coating metal containers to prevent degradation.
What is the significance of the 150 parts per million concentration of Lewis acid inhibitor?
This concentration is specified to ensure the effective stabilization of sevoflurane.
How has the validity of the patent been challenged?
The Federal Circuit invalidated the patent, finding that the claims were not valid due to prior art and other issues.
What are the implications for generic drug manufacturers?
Generic manufacturers must ensure their products do not infringe on the patent claims, particularly regarding the use of specific container coatings and inhibitors.
Sources
- Abbott Laboratories v. Baxter Healthcare Corp., No. 04 C 836.
- WO2013149263A1 - Liquid inhalational anesthetic container.
- Patent Claims Research Dataset - USPTO.
- Search for patents - USPTO.
- Federal Circuit Invalidates Abbott's Sevoflurane Patent in Case Against Baxter.
