United States Patent 6,475,521: A Detailed Analysis of Scope and Claims
Introduction
United States Patent 6,475,521, titled "Biphasic controlled release delivery system for high solubility pharmaceuticals and method," is a significant innovation in the field of pharmaceutical delivery systems. This patent, particularly relevant for the treatment of diabetes, introduces a novel approach to managing the release of highly soluble drugs like metformin.
Background
The patent addresses a critical issue in pharmaceutical formulation: the controlled release of drugs with high water solubility. Drugs like metformin, commonly used to treat diabetes, have a limited window of absorption, primarily in the upper gastrointestinal tract. This limitation necessitates a delivery system that can manage the release of the drug effectively to maintain therapeutic levels over an extended period.
Scope of the Patent
Overview of the Delivery System
The biphasic controlled release delivery system described in the patent is a heterogeneous two-phase system. This system consists of:
- Inner Solid Particulate Phase: This phase includes individual granules or particles containing the drug (e.g., metformin or its salt) and an extended release material. The extended release material can be one or more hydrophilic polymers, hydrophobic polymers, or other hydrophobic materials like waxes, fatty alcohols, and fatty acid esters[1][2].
- Outer Solid Continuous Phase: This phase is where the granules or particles of the inner solid particulate phase are dispersed and embedded. The outer phase is primarily formed of an extended release material similar to those in the inner phase[1].
Key Components
- Drug: The patent specifically mentions metformin or its salt as the primary drug, but the system can be adapted for other highly soluble pharmaceuticals.
- Extended Release Materials: These include hydrophilic and hydrophobic polymers, as well as other materials like waxes and fatty alcohols. These materials control the release rate of the drug.
- Dual Phase Design: The biphasic design allows for an initial rapid release followed by a sustained release, ensuring that the drug is available over an extended period[1][2].
Claims of the Patent
Main Claims
The patent claims cover the following:
- The biphasic controlled release delivery system itself.
- The method of preparing this delivery system.
- The use of this system for treating conditions such as diabetes.
- Specific formulations involving metformin and other extended release materials[1][2].
Detailed Claim Structure
The claims are structured to cover various aspects of the invention, including:
- Composition Claims: These claims describe the composition of the inner and outer phases, including the types of polymers and other materials used.
- Method Claims: These claims outline the process of preparing the biphasic delivery system.
- Use Claims: These claims specify the therapeutic uses of the delivery system, particularly for treating diabetes[1].
Patent Landscape
Prior Art and Related Patents
The patent landscape around controlled release delivery systems is extensive. Other patents, such as WO 2004/012699 A2 and US2003/0170302, describe similar concepts but with different approaches:
- WO 2004/012699 A2: This patent discloses a modified release dosage form using a dual retard technique with micro matrix particles and hydrophobic release controlling agents[2].
- US2003/0170302: This patent describes an extended release pharmaceutical tablet of metformin with a core containing metformin and a coating permeable to metformin[2].
Competitive Advantage
The biphasic controlled release delivery system of US 6,475,521 offers a unique advantage by providing a tailored release profile that can be adjusted based on the specific needs of the drug and the patient. This flexibility, combined with the use of both hydrophilic and hydrophobic materials, allows for a more controlled and sustained release of highly soluble drugs like metformin[1].
Impact on Pharmaceutical Formulation
Clinical Implications
The biphasic delivery system has significant clinical implications, particularly for patients with diabetes:
- Improved Bioavailability: The system ensures that the drug is released in a manner that maximizes its absorption and therapeutic effect.
- Reduced Dosage Frequency: By providing a sustained release, the system can reduce the need for frequent dosing, improving patient compliance[1].
Manufacturing Considerations
The patent also addresses manufacturing aspects, providing a clear method for preparing the biphasic delivery system. This includes the formulation of the inner and outer phases and the process of embedding the granules or particles into the outer phase[1].
Legal Status and Expiration
The patent US 6,475,521 has expired, which means that the technology described is now in the public domain. This expiration allows other manufacturers to use and build upon this technology without needing to obtain a license from the original patent holders[1].
Key Takeaways
- Biphasic Design: The patent introduces a biphasic controlled release delivery system with an inner solid particulate phase and an outer solid continuous phase.
- Extended Release Materials: The system uses hydrophilic and hydrophobic polymers and other materials to control the release of highly soluble drugs.
- Therapeutic Use: The primary therapeutic use is for treating diabetes with metformin.
- Manufacturing Process: The patent provides a detailed method for preparing the delivery system.
- Public Domain: The patent has expired, making the technology available for public use.
FAQs
What is the main innovation of US Patent 6,475,521?
The main innovation is the biphasic controlled release delivery system designed for highly soluble pharmaceuticals like metformin.
What are the key components of the biphasic delivery system?
The key components include the inner solid particulate phase with the drug and extended release materials, and the outer solid continuous phase where the granules or particles are embedded.
How does the biphasic system improve drug delivery?
The system provides an initial rapid release followed by a sustained release, ensuring the drug is available over an extended period and improving bioavailability.
What is the therapeutic use of this delivery system?
The primary therapeutic use is for treating diabetes with metformin.
Is the technology described in US Patent 6,475,521 still under patent protection?
No, the patent has expired, and the technology is now in the public domain.
Sources
- US6475521B1 - Biphasic controlled release delivery system for high solubility pharmaceuticals and method - Google Patents
- US20080181946A1 - Controlled Release Delivery System For Metformin - Google Patents
- Patent Claims and Patent Scope - Hoover Institution
- Patent 2826640 Summary - Canadian Patents Database
- Controlled release metformin compositions - PubChem
