United States Patent 6,264,987: A Detailed Analysis of Scope and Claims
Introduction
United States Patent 6,264,987, titled "Method for preparing microparticles having a selected polymer molecular weight," is a significant patent in the field of pharmaceutical and materials science. This patent, issued on July 24, 2001, outlines a method for producing microparticles with specific polymer molecular weights, which is crucial for various medical and industrial applications.
Background of the Invention
The patent addresses the need for a controlled method to prepare microparticles, particularly in the context of pharmaceutical formulations. Traditional methods often resulted in microparticles with inconsistent molecular weights, which could affect the efficacy and stability of the final product. The inventors aimed to develop a process that would allow for the precise control of polymer molecular weight, thereby enhancing the quality and reliability of microparticles[1].
Summary of the Invention
The patent describes a method for preparing microparticles by controlling the hold time and temperature of a solution containing a nucleophilic compound. This process involves several key steps:
- Solution Preparation: A solution is prepared containing a polymerizable monomer and a nucleophilic compound.
- Polymerization: The solution is subjected to specific temperature and hold time conditions to initiate polymerization.
- Microparticle Formation: The resulting polymer is then processed to form microparticles.
- Molecular Weight Control: The molecular weight of the polymer is controlled by adjusting the hold time and temperature, allowing for the production of microparticles with a selected molecular weight[1].
Claims of the Patent
The patent includes several claims that define the scope of the invention:
- Claim 1: A method for preparing microparticles having a selected polymer molecular weight, involving the steps of preparing a solution, polymerizing the monomer, and forming microparticles.
- Claim 2-5: Variations of the method, including different conditions for temperature and hold time.
- Claim 6-10: Specific embodiments of the method, such as using different types of nucleophilic compounds and polymerizable monomers.
- Claim 11-15: Claims related to the apparatus and systems used for carrying out the method[1].
Scope of the Patent
The scope of the patent is broad yet specific, covering various aspects of microparticle preparation:
- Polymer Molecular Weight Control: The patent provides a method to control the molecular weight of the polymer, which is essential for ensuring the consistency and quality of the microparticles.
- Pharmaceutical Applications: The method is particularly useful in pharmaceutical formulations where microparticles are used as drug delivery systems.
- Industrial Applications: The patent also has implications for other industries where microparticles are used, such as in cosmetics and food products[1].
Patent Landscape
The patent landscape surrounding US 6,264,987 is complex and involves several related patents and technologies:
- Related Patents: Other patents, such as US 6,987,111, describe similar methods for preparing sustained-release microparticles using different techniques like coacervation and interfacial polymerization[4].
- Competing Technologies: Technologies like PROLEASE(R) and ALZAMER(R) Depot injection, described in other patents, offer alternative methods for sustained-release formulations[4].
- International Filings: The patent's scope is not limited to the United States; similar methods and technologies are being developed and patented globally, as seen in international filings and classifications[2].
Impact on Industry
The patent has significant implications for the pharmaceutical and materials science industries:
- Improved Drug Delivery: The ability to control the molecular weight of polymers in microparticles enhances the efficacy and stability of drug delivery systems.
- Cost and Efficiency: The method described in the patent can potentially reduce the cost and complexity of producing microparticles, making it more efficient for industrial-scale production.
- Innovation: The patent encourages further innovation in the field by providing a foundational method that can be built upon and improved[1].
Legal Status and Expiration
The patent has expired, which means that the method described is now in the public domain. This expiration allows other companies and researchers to use and build upon the method without needing to obtain a license or pay royalties[1].
Citations and References
The patent references several prior art documents and publications, highlighting the evolution of microparticle preparation methods. For example:
"The contents of these patents are incorporated herein by reference in their entirety."[4]
Key Takeaways
- Controlled Molecular Weight: The patent provides a method to control the molecular weight of polymers in microparticles.
- Pharmaceutical and Industrial Applications: The method is crucial for pharmaceutical formulations and has broader industrial applications.
- Expired Patent: The patent is now in the public domain, allowing for widespread use and further innovation.
- Complex Patent Landscape: The patent is part of a larger landscape involving related patents and competing technologies.
Frequently Asked Questions (FAQs)
Q: What is the main focus of United States Patent 6,264,987?
A: The main focus is a method for preparing microparticles with a selected polymer molecular weight.
Q: How does the patent control the molecular weight of polymers?
A: The patent controls the molecular weight by adjusting the hold time and temperature of a solution containing a nucleophilic compound.
Q: What are the primary applications of this patent?
A: The primary applications are in pharmaceutical formulations and other industries where microparticles are used.
Q: Is the patent still in force?
A: No, the patent has expired and is now in the public domain.
Q: How does this patent fit into the broader patent landscape?
A: It is part of a complex landscape involving related patents and competing technologies for preparing microparticles and sustained-release formulations.
