Transdermal Patch Circumferential Diffusion Barrier
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Solution Overview
Problem
Existing transdermal therapeutic systems face challenges in preventing the migration of pharmacologically active substances into the adhesive layer of the fixing patch, leading to uncontrolled losses and reduced efficacy, particularly due to complex and error-prone manufacturing processes and material compatibility issues.
Innovation Solution
A transdermal therapeutic system with a circumferential zone of reduced thickness between the active-substance-containing polymer matrix and the active-substance-free pressure-sensitive adhesive, produced using a punching tool with a hollow cylinder and cutting blade, acts as a diffusion barrier to prevent substance migration, allowing for simpler and cost-effective production while maintaining good adhesive properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the adhesive carrier layer is coated completely with pressure-sensitive adhesive to improve adhesive properties, then the adhesive performance is improved, but active substance migration into the adhesive layer occurs
Solution Approach 1:
The adhesive carrier layer is coated with pressure-sensitive adhesive only in specific zones (circumferential area and/or corner areas), leaving other areas adhesive-free. This local differentiation allows the adhesive to provide fixation where needed while preventing active substance migration in areas where the adhesive would cause harm.
2Loss of substance
If cornered patches are used to minimize cutting losses, then material utilization is improved, but detachment from skin occurs more easily
Solution Approach 1:
The adhesive carrier layer provides differentiated adhesive coverage with enhanced adhesive presence at corner areas and circumferential zones. This local concentration of adhesive material compensates for the reduced surface area of cornered patches, maintaining fixation stability while allowing cornered geometry for efficient cutting utilization.
3Reliability
If a fixing patch with rounded corners is affixed over cornered active-substance patches to improve hold, then fixation stability is improved, but active substance migration into the fixing patch adhesive occurs
Solution Approach 1:
The adhesive carrier layer is divided into distinct functional zones: adhesive zones for fixation and adhesive-free zones for preventing migration. This segmentation allows the single patch to simultaneously provide both fixation stability and migration prevention without requiring a separate fixing patch.
Solution Approach 2:
The adhesive-free zones on the adhesive carrier layer act as intermediary barriers between the active substance reservoir and any external adhesive layers. These zones prevent direct contact and migration pathways while allowing the adhesive zones to provide necessary fixation.
4Loss of substance
If various approaches are used to counter migration problem, then active substance loss is reduced, but manufacturing complexity increases
Solution Approach 1:
The adhesive carrier layer combines multiple functions into a single integrated component: fixation through adhesive zones and migration prevention through adhesive-free zones. This merging eliminates the need for separate fixing patches or complex multi-layer structures, simplifying manufacturing while effectively preventing active substance loss.
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 reduced thickness zone effectively prevents the migration of active substances into the adhesive layer, ensuring consistent dosing and improved adhesive performance, thus enhancing the system's effectiveness and manufacturing efficiency.
Implementation Method 1
a circumferential zone with reduced coating thickness with the active-substance-containing polymer matrix and/or with the active-substance-free pressure-sensitive adhesive, which acts as a diffusion barrier and prevents lateral diffusion of the pharmacologically active substance and/or of one or more excipients into the adhesive of the adhesive carrier layer
Data Source
AI summary
The present invention relates to a transdermal therapeutic system (1) comprisingan active-substance carrier layer (2) having at least one active-substance-containing polymer matrix (3) applied to the active-substance carrier layer (2), said matrix comprising at least one pressure-sensitive adhesive and at least one pharmacologically active substance absorbable through human or animal skin, andan adhesive carrier layer (6) coated as completely as possible with an active-substance-free pressure-sensitive adhesive (7), said adhesive carrier layer being bonded by means of the active-substance-free pressure-sensitive adhesive (7) directly to the flat side of the active-substance carrier layer (2) facing away from the active-substance-containing polymer matrix (3),wherein the adhesive carrier layer (6) projecting circumferentially beyond the edge of the active-substance carrier layer (2), wherein the system is characterized in that between the active-substance-containing polymer matrix (3) and the active-substance-free pressure-sensitive adhesive (7) there is a circumferential zone (4) having a reduced thickness of coating with the active-substance-containing polymer matrix (3) and/or with the active-substance-free pressure-sensitive adhesive (7). The invention further relates to the use of this transdermal therapeutic system and to a kit that contains it.