Detailed Analysis of the Scope and Claims of United States Patent 4,559,222
Introduction
United States Patent 4,559,222, filed on December 17, 1985, is a significant patent in the field of pharmaceutical technology, particularly focusing on transdermal drug delivery systems. This patent describes a multilayer transdermal system designed for the delivery of clonidine, a medication used to treat various conditions including hypertension, migraines, anxiety, and more.
Background and Context
Transdermal drug delivery systems have been a focus of pharmaceutical research for several decades due to their ability to provide steady and controlled release of medications directly through the skin. This method avoids the gastrointestinal tract and first-pass metabolism, often resulting in better bioavailability and patient compliance[1].
Scope of the Patent
The patent 4,559,222 specifically relates to matrix systems, a type of transdermal delivery system where the active ingredient is embedded directly into a semi-solid matrix made of polymers. Here are the key aspects of the scope:
Active Ingredient and Indications
- The patent focuses on the delivery of clonidine, which is used for treating hypertension, migraines, anxiety, hyperkinetic behavioral disorders, withdrawal symptoms from alcohol or drug withdrawal, and menopausal symptoms[1].
System Components
- The transdermal system consists of multiple layers:
- Active Substance-Containing Layer: This layer includes clonidine base in mineral oil along with colloidal silicon dioxide.
- Adhesive Layer: A polyisobutylene adhesive is used.
- Microporous Layer: Applied on top of the adhesive layer.
- Impermeable Foil: Covers the active substance-containing layer to prevent premature release of the drug[1].
Claims of the Patent
The patent claims are detailed and specific, outlining the structure and function of the transdermal system:
Layered Structure
- The patent describes a multilayer system with a specific arrangement of layers:
- A first layer containing clonidine in mineral oil and colloidal silicon dioxide.
- A second layer of polyisobutylene adhesive.
- A microporous membrane applied on this adhesive layer.
- An additional adhesive layer for skin attachment[1].
Material Specifications
- The use of specific materials such as polyisobutylene, mineral oil, and colloidal silicon dioxide is detailed.
- The impermeable foil covering the active substance-containing layer is also specified[1].
Delivery Rate
- The patent mentions the delivery rate of clonidine, which can range from 10 to 1000 μg per day, with a more specific range of 50 to 500 μg per day in some embodiments[1].
Advantages and Innovations
The patent introduces several innovations and advantages over previous transdermal systems:
Improved Adhesive Properties
- The use of polyisobutylene adhesive enhances the skin adhesion properties of the patch.
- The microporous layer improves the permeability and stability of the system[1].
Controlled Release
- The layered structure ensures a controlled and steady release of clonidine through the skin, which is crucial for maintaining therapeutic levels of the drug over an extended period.
Patent Landscape Analysis
To understand the broader context and impact of this patent, a patent landscape analysis is essential:
Identifying Trends and Key Players
- This patent is part of a larger trend in pharmaceutical technology focusing on transdermal delivery systems.
- Key players in this field include pharmaceutical companies and research institutions that have developed similar or improved systems over the years[3].
Analyzing Citations and Evolution
- The patent has been cited in subsequent patents and research papers, indicating its influence on the development of newer transdermal systems.
- Evolution in materials and design has led to improved versions, such as those described in U.S. Patents 5,762,952 and 5,958,446, which address some of the limitations of the original system[1].
Competitive Landscape
The competitive landscape in transdermal drug delivery is dynamic, with continuous innovations and improvements:
Market Impact
- Patents like 4,559,222 have driven the development of commercial products that have significantly impacted the pharmaceutical market.
- Companies have invested heavily in research and development to create more efficient and patient-friendly transdermal systems[3].
Legal and Regulatory Considerations
- Correct inventorship and the absence of deceptive intent are crucial for the enforceability of patents. Errors in inventorship can lead to unenforceable patents, as seen in cases like Frank’s Casing Crew v. PMR Technologies[2].
Key Takeaways
- Innovative Design: The patent introduces a multilayer transdermal system with improved adhesive and permeability properties.
- Controlled Release: The system ensures a steady and controlled release of clonidine, enhancing therapeutic efficacy.
- Impact on Industry: The patent has influenced subsequent developments in transdermal drug delivery systems.
- Legal Considerations: Correct inventorship and ethical practices are essential for patent enforceability.
FAQs
What is the primary active ingredient in the transdermal system described in U.S. Patent 4,559,222?
The primary active ingredient is clonidine.
What are the main indications for the use of this transdermal system?
The system is used for treating hypertension, migraines, anxiety, hyperkinetic behavioral disorders, withdrawal symptoms from alcohol or drug withdrawal, and menopausal symptoms.
What is the layered structure of the transdermal system?
The system consists of an active substance-containing layer, a polyisobutylene adhesive layer, a microporous membrane, and an additional adhesive layer for skin attachment.
Why is the impermeable foil important in this system?
The impermeable foil prevents premature release of the drug, ensuring controlled delivery.
What are some of the innovations introduced by this patent?
The patent introduces improved adhesive properties and a microporous layer for enhanced permeability and stability.
Cited Sources
- EP1103260A2 - Système transdermique pour l ... - Google Patents
- Determining Inventorship for US Patent Applications
- How to Do Patent Landscape Analysis
