United States Patent 5,731,355: A Detailed Analysis
Introduction
The United States Patent 5,731,355, titled "Pharmaceutical Compositions of Propofol and Edetate," is a crucial patent in the pharmaceutical industry, particularly in the field of anesthetic formulations. This patent, along with its related patents (5,714,520 and 5,731,356), has been the subject of several legal battles and is essential for understanding the patent landscape in this domain.
Background and History
The patent was issued on March 24, 1998, as a divisional application based on the parent patent 5,714,520. It is assigned to Abraxis Bioscience, Inc., which later transferred the rights to Fresenius Kabi USA, LLC[2].
Scope and Meaning of Patent Claims
To determine the scope and meaning of the patent claims, it is essential to analyze the specification and the claims themselves.
Specification Analysis
The specification of the patent describes the use of edetate (ethylenediaminetetraacetic acid, EDTA) and its derivatives as antimicrobial agents in propofol formulations. The patentees experimented with various preservatives before identifying edetate as the only agent that met their requirements. This indicates that the term "edetate" and its derivatives have a specific, narrow meaning within the context of the patent[1].
Claim Construction
The claims of the patent are critical in defining the scope of protection. Claims 1-14, 16-32, and 34 of each patent, as well as claims 38 and 39 of the '520 patent, are particularly relevant. These claims specify the composition of propofol and edetate, including the use of edetate and its derivatives as antimicrobial agents. The court has adopted a construction of "edetate" as "EDTA and derivatives of EDTA, such as salts," which is crucial for determining infringement[2].
Infringement Analysis
Determining infringement involves a two-step analysis: first, construing the claims, and then comparing the construed claims to the allegedly infringing device.
Claim Construction and Infringement
In the case of Abraxis Bioscience, Inc. v. Mayne Pharma (USA), Inc., the court determined that Mayne's formulation infringed the asserted claims under the doctrine of equivalents. This decision was based on the narrow meaning of "edetate" and its derivatives as defined in the specification[1].
Doctrine of Equivalents
The doctrine of equivalents allows for infringement to be found if the accused product performs substantially the same function in substantially the same way with substantially the same result as each claim limitation of the patented product. However, statements by applicants that characterize the unexpected properties of the invention can limit the scope of available equivalents[2].
Patent Landscape Analysis
Understanding the patent landscape around U.S. Patent 5,731,355 involves several key steps:
Defining Scope and Keywords
The analysis begins by defining the technology field and identifying relevant keywords. In this case, the keywords would include "propofol," "edetate," "pharmaceutical compositions," and "antimicrobial agents"[3].
Searching and Organizing Patents
Using patent databases, relevant patents are retrieved based on the chosen keywords. These patents are then organized by factors such as filing date, assignee, and technology subcategories. For example, patents related to propofol formulations and antimicrobial agents would be categorized together[3].
Identifying Trends and Key Players
The analysis recognizes patterns in patent filings and identifies significant contributors. In this domain, companies like Fresenius Kabi USA, LLC, and Dr. Reddy's Laboratories, Ltd. are key players due to their involvement in propofol formulations and related litigation[2].
Analyzing Citations and Evolution
Studying how patents reference each other helps understand their impact and development. The '355 patent, for instance, is closely related to the '520 and '356 patents, all of which share a common specification and address similar technological challenges[1].
Generating Insights for Decisions
The analysis translates into practical guidance for strategic choices. For example, understanding the competitive landscape and potential legal vulnerabilities can help companies navigate the complex environment of pharmaceutical patent law[3].
Economic and Strategic Value
The value of a patent like U.S. Patent 5,731,355 can be substantial, both economically and strategically.
Economic Value
The economic value of patents can vary widely, with median prices ranging from $108,000 to $250,000 per family of patents. High-profile deals, such as the purchase of Nortel's patents by Rockstar Bidco, highlight the significant financial value that patents can hold[4].
Strategic Value
Strategically, holding a patent like the '355 patent provides a competitive advantage by protecting proprietary formulations and preventing generic competition until the patent expires. This can be crucial for maintaining market share and revenue in the pharmaceutical industry[4].
Legal Implications and Litigation
The '355 patent has been involved in several legal battles, which underscore its importance.
Abraxis Bioscience, Inc. v. Mayne Pharma (USA), Inc.
This case established the narrow meaning of "edetate" and its derivatives, which has been pivotal in subsequent infringement determinations[1].
Fresenius Kabi USA, LLC v. Dr. Reddy's Laboratories, Ltd.
In this case, Fresenius Kabi asserted that Dr. Reddy's generic propofol products would infringe the claims of the '355 patent, among others. The court's construction of "edetate" was critical in this litigation[2].
Key Takeaways
- Narrow Claim Construction: The term "edetate" and its derivatives have a specific, narrow meaning within the context of the patent.
- Infringement Analysis: Determining infringement involves a two-step analysis of claim construction and comparison to the allegedly infringing device.
- Patent Landscape: Understanding the patent landscape involves defining scope, searching and organizing patents, identifying trends, analyzing citations, and generating insights.
- Economic and Strategic Value: Patents like the '355 patent hold significant economic and strategic value.
- Legal Implications: The patent has been involved in several legal battles that highlight its importance in protecting proprietary formulations.
Frequently Asked Questions (FAQs)
What is the main subject of U.S. Patent 5,731,355?
The main subject of U.S. Patent 5,731,355 is pharmaceutical compositions of propofol and edetate, specifically focusing on the use of edetate as an antimicrobial agent.
Who are the key players involved in the patent landscape around this patent?
Key players include Fresenius Kabi USA, LLC, and Dr. Reddy's Laboratories, Ltd., among others involved in propofol formulations and related litigation.
How is the term "edetate" defined in the patent?
The term "edetate" is defined as "EDTA and derivatives of EDTA, such as salts," based on the specification and court constructions.
What is the significance of the doctrine of equivalents in this patent?
The doctrine of equivalents allows for infringement to be found if the accused product performs substantially the same function in substantially the same way with substantially the same result as each claim limitation of the patented product.
What is the economic value of patents like U.S. Patent 5,731,355?
The economic value can range widely, with median prices for patent families in the pharmaceutical sector often being in the hundreds of thousands of dollars.
Cited Sources
- Abraxis Biosci., Inc. v. Mayne Pharma (Usa), 467 F.3d 1370 - Casetext
- Fresenius Kabi USA, LLC, Dr. Reddy's Laboratories, Ltd. and Dr. Reddy's Laboratories, Inc. - IN THE UNITED STATES DISTRICT COURT
- How to Do Patent Landscape Analysis - Goldstein Patent Law
- The value of a patent - Perpetual Motion Patents
