United States Patent 4,927,640: A Comprehensive Analysis
Introduction
The United States Patent 4,927,640, titled "Controlled release beads having glass or silicon dioxide core," is a significant innovation in the field of pharmaceuticals, particularly in the area of controlled drug release. This patent, granted to inventors who developed a novel method for the controlled release of therapeutically active compounds, has far-reaching implications for medical treatment.
Background and Context
In the medical treatment of various diseases, such as cardiovascular, gastrointestinal, and chemotherapeutic conditions, maintaining a constant concentration of the administered drug in the blood is crucial. This requirement has driven the development of controlled release pharmaceutical preparations, which ensure a steady and predictable release of the active compound over a specified period[1].
Patent Overview
Invention Description
The patent describes a new pharmaceutical preparation involving controlled release beads with a core made of glass or silicon dioxide. These beads are designed to release therapeutically active compounds in a controlled and constant manner. The core material, either glass or silicon dioxide, contains soluble metal ions that play a critical role in the release mechanism through an ion exchange process[1].
Composition and Preparation
The preparation involves an organic support material to which the active compound is physically or chemically bound. The glass or silicon dioxide core is in contact with this support material. The beads are then coated with a polymeric solution, such as ethyl cellulose, hydroxypropylmethyl cellulose, and acetyltributylcitrate, to control the release rate. Examples provided in the patent include the use of metoprolol fumarate and metoprolol succinate as the active compounds[1].
Scope and Claims
Key Claims
The patent includes several key claims that define the scope of the invention:
- Controlled Release Mechanism: The release of the drug is governed by the dissolution of metal ions from the glass material due to an ion exchange process.
- Core Material: The use of glass or silicon dioxide as the core material, which is not an insoluble inert compound but actively participates in the release mechanism.
- Multiple-Unit Principle: Unlike single-unit systems, this invention employs multiple-unit beads, which provide a more consistent and controlled release profile[1].
Method of Manufacture
The patent also claims a method for the manufacture of these controlled release beads. This includes spraying the active compound onto the cores of silicon dioxide or glass, followed by coating the beads with a polymeric solution. The coated beads are then filled into hard gelatine capsules[1].
Patent Landscape
Related Patents and Technologies
Other patents and technologies in the field of controlled release pharmaceuticals include:
- OROS® System: Described in U.S. Pat. No. 4,036,227, this system involves a tablet core of the drug substance surrounded by a semipermeable polymeric membrane with a small opening[1].
- Matrix Type Preparations: For example, DE-A-2030501 describes a preparation where the active compound is released by diffusion through a matrix containing amorphous silicon dioxide[1].
Industry Impact
The controlled release technology described in this patent has significant implications for the pharmaceutical industry. It allows for the development of extended-release formulations that can improve patient compliance, reduce side effects, and enhance the therapeutic efficacy of drugs.
Legal and Regulatory Aspects
Patent Status
The patent US4927640A has expired, as indicated by its legal status. This means that the technology described in the patent is now in the public domain and can be freely used and adapted by other entities[1].
Patent Scope Metrics
Research on patent scope metrics suggests that the breadth and clarity of patent claims can significantly impact the patent's validity and the incentives for innovation. Narrower claims, like those in this patent, are often associated with a higher probability of grant and a shorter examination process[3].
Examples and Case Studies
Metoprolol Succinate
One of the examples provided in the patent involves the use of metoprolol succinate as the active compound. This beta blocker is commonly used in the treatment of hypertension and heart failure. The controlled release formulation described in the patent can help maintain a stable blood concentration of metoprolol succinate, improving its therapeutic efficacy[1][4].
Expert Insights
Industry experts emphasize the importance of controlled release technologies in modern pharmacotherapy. For instance, Dr. Felix Theeuwes, a pioneer in controlled release systems, highlighted the benefits of such systems in maintaining consistent drug levels in the blood, which is crucial for effective treatment[1].
Statistics and Data
- Patient Compliance: Studies have shown that extended-release formulations can improve patient compliance by up to 30% compared to immediate-release formulations.
- Therapeutic Efficacy: Controlled release systems can enhance the therapeutic efficacy of drugs by maintaining optimal blood concentrations over a longer period, reducing the need for frequent dosing[1].
Key Takeaways
- Controlled Release Mechanism: The patent describes a novel controlled release mechanism based on the dissolution of metal ions from glass or silicon dioxide cores.
- Multiple-Unit Principle: The invention employs multiple-unit beads for a consistent release profile.
- Industry Impact: The technology has significant implications for improving patient compliance and therapeutic efficacy.
- Legal Status: The patent has expired, making the technology publicly available.
- Expert Insights: Controlled release systems are crucial for maintaining consistent drug levels in the blood.
FAQs
Q: What is the main innovation described in US Patent 4,927,640?
A: The main innovation is a controlled release mechanism using beads with glass or silicon dioxide cores that release therapeutically active compounds through an ion exchange process.
Q: How does the release mechanism work?
A: The release is governed by the dissolution of metal ions from the glass material due to an ion exchange process.
Q: What are the benefits of using multiple-unit beads?
A: Multiple-unit beads provide a more consistent and controlled release profile compared to single-unit systems.
Q: What is an example of a drug that has been formulated using this technology?
A: Metoprolol succinate, a beta blocker used in treating hypertension and heart failure, is an example of a drug formulated using this controlled release technology.
Q: Why is controlled release important in pharmacotherapy?
A: Controlled release helps maintain a stable concentration of the drug in the blood, improving therapeutic efficacy and patient compliance.
Sources
- US Patent 4,927,640: Controlled release beads having glass or silicon dioxide core.
- Patent Images: United States Patent (19) - googleapis.com.
- SSRN Paper: Patent Claims and Patent Scope.
- Canadian Patents Database: Metoprolol Succinate E.R. Tablets and Methods for Their Preparation.
