Adhesive Patch Using Carboxy-Free Copolymer for Rivastigmine Stability
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Solution Overview
Problem
Adhesive patches containing rivastigmine face challenges in maintaining storage stability and achieving sufficient skin permeability to effectively treat Alzheimer's disease, as they often experience decomposition and volatilization issues without the use of antioxidants or volatilization inhibitors.
Innovation Solution
An adhesive patch utilizing an alkyl (meth)acrylate-based copolymer without acrylic monomers containing a carboxy group, which provides excellent storage stability and increased skin permeability of rivastigmine without the need for additives like antioxidants or volatilization inhibitors, ensuring a consistent drug effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If rivastigmine is formulated in an adhesive patch without antioxidants or volatilization inhibitors, then the device complexity is reduced, but the storage stability deteriorates due to decomposition and volatilization
Solution Approach 1:
The patent introduces a specific adhesive polymer as an intermediary substance that mediates between rivastigmine and the environment. This polymer forms a protective matrix that prevents decomposition and volatilization without requiring additional antioxidants or inhibitors, thus resolving the contradiction by using one substance to protect another.
Solution Approach 2:
The patent changes the chemical parameters of the adhesive formulation by selecting specific polymers with particular functional groups (carboxylic acid, hydroxyl, or amine groups) that can interact with rivastigmine. This parameter change in the adhesive composition enables improved storage stability without adding separate protective agents.
2Quantity of substance
If rivastigmine concentration in the adhesive patch is increased, then the skin permeability and drug effect are improved, but the storage stability deteriorates due to increased volatilization
Solution Approach 1:
The adhesive polymer acts as an intermediary that binds to rivastigmine molecules, forming a stable complex that prevents volatilization even at high concentrations. This mediator enables the formulation to maintain both high drug content and storage stability simultaneously.
Solution Approach 2:
The patent creates a composite material system where rivastigmine is combined with specific adhesive polymers having functional groups that interact with the drug. This composite structure allows high rivastigmine concentration while maintaining stability through the protective polymer matrix.
3Force
If conventional acrylic adhesives with carboxy groups are used, then the adhesion performance is improved, but the skin permeability of rivastigmine is insufficient
Solution Approach 1:
The patent applies local quality by incorporating specific functional groups (carboxylic acid, hydroxyl, or amine) at specific locations within the adhesive polymer structure. These localized functional groups provide both adhesion to skin and enhanced permeability pathways for rivastigmine, resolving the contradiction between adhesion strength and drug permeation.
Solution Approach 2:
The patent uses composite adhesive materials that combine the adhesion properties of acrylic polymers with additional functional groups that enhance skin permeability. This composite approach allows the adhesive to simultaneously provide strong bonding and facilitate drug penetration through the skin barrier.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The adhesive patch achieves enhanced storage stability and increased skin permeability, with a cumulative absorbed amount of rivastigmine exceeding 0.3 mg/cm²/24hr, effectively addressing the limitations of previous formulations.
Implementation Method 1
the skin permeability of rivastigmine has been increased to such an extent that the amount of percutaneous absorption required for treating Alzheimer's disease is obtained
Implementation Method 2
the adhesive patch has excellent rivastigmine storage stability
Implementation Method 3
without containing an antioxidant which was contained in the case of Patent Literatures 2 and 3 or without using a volatilization inhibitor for rivastigmine
Data Source
AI summary
Provided is an adhesive patch which has excellent rivastigmine storage stability and an increased skin permeability of rivastigmine to such an extent that the amount of percutaneous absorption required for treating Alzheimer's disease is obtained. This adhesive patch includes a backing and an adhesive layer containing rivastigmine and an alkyl (meth)acrylate-based copolymer that does not contain any acrylic monomer component having a carboxy group, the adhesive layer being laid on one side of and integrated with the backing.