Electrophoretic Transdermal System pH-Controlled Matrix
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Solution Overview
Problem
Transdermal therapeutic systems face limitations in controlling the release of active substances through the skin, particularly for larger or more complex molecules, due to the permeability barrier of the stratum corneum, and existing iontophoretic systems are large and cumbersome.
Innovation Solution
An electrophoretic transdermal system with a matrix containing basic or acidic active substances and electrodes, where the pH is controlled to maintain the active substances in an ionic form, allowing for controlled release and improved skin permeation using a voltage-controlled system with a silver anode and pressure-sensitive adhesive layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If passive diffusion is used to transport active substance through the skin, then the system is simple in construction, but the release rate cannot be controlled and larger molecules cannot permeate through the skin
Solution Approach 1:
The patent replaces passive diffusion (mechanical concentration gradient-driven transport) with electrophoretic transport (electric field-driven ion transport). The system uses electrodes to generate an electric field that propels ionized active substances through the skin, enabling controlled delivery of larger molecules while maintaining relative system simplicity.
Solution Approach 2:
The patent changes the transport mechanism parameter from concentration-gradient-driven diffusion to electric-field-driven electrophoresis. By applying voltage across the skin, the system controls the movement of ionized active substances, enabling both control over release rates and permeation of larger molecules that cannot diffuse passively.
2Productivity
If iontophoresis is used to improve skin permeation, then larger molecules can be transported through the skin, but the system becomes large and cumbersome
Solution Approach 1:
The patent extracts only the essential electrophoretic transport function from traditional iontophoresis systems. By using a simplified electrode configuration where one electrode contacts the skin and the other is remote, the system eliminates the need for large aqueous buffer solutions and gel structures, achieving compact size while maintaining permeation capability.
Solution Approach 2:
The patent employs a thin film or patch structure containing the active substance and electrode, allowing flexible application to the skin surface. This thin-film approach replaces bulky traditional iontophoresis apparatus, enabling portable and user-friendly delivery systems.
3Productivity
If the pH of the matrix is adjusted to maintain active substance in ionic form, then controlled release is improved, but oxidation or precipitation risk increases
Solution Approach 1:
The patent applies voltage periodically or in controlled intervals rather than continuously. This periodic electrophoretic stimulation allows the active substance to be transported through the skin in pulses, reducing the time the substance spends in vulnerable ionic states that could lead to oxidation or precipitation, while maintaining controlled release effectiveness.
Solution Approach 2:
The patent uses the electric field as an intermediary mechanism to transport the active substance. Rather than relying on pH adjustment alone, the electric field provides a controlled pathway for ionized substances through the skin, minimizing exposure time to conditions that cause oxidation or precipitation while maintaining transport efficiency.
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
Enables sustained release of active substances over 24 hours or longer, minimizing side effects and optimizing plasma levels, with enhanced skin permeation and reduced risk of oxidation or precipitation, while maintaining operational reliability and ease of application.
Implementation Method 1
In electrophoretic transdermal systems, ionic drugs can be propelled through the skin using two electrodes and a power source
Implementation Method 2
The ionically present drug molecules are driven out of an electrically conductive drug reservoir and into the skin along the field formed by the potential difference between the electrodes
Implementation Method 3
The system also includes a pressure-sensitive adhesive for attaching the TDS to the skin's surface
Data Source
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AI summary
The invention relates to a transdermal application system for the administration of at least one agent through the skin, comprising a first electrode (1), a second electrode (2) and a matrix (3) between the first electrode (1) and eh second electrode (2) and contains at least one agent (4) enthält, selected from basic or acidic agents, wherein the system is designed such that using a voltage applied to the electrodes the pH value of the matrix does not exceed the pK value of the agent (4) in the case of a basic agent (4) and, in the case of an acidic agent (4) does not drop below the pK value of the agent (4).