Transdermal Therapeutic System with Barrier Layer Openings
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Solution Overview
Problem
Transdermal therapeutic systems lack controlled active substance release mechanisms, leading to rapid release and potential premature detachment from the skin, especially when a low dosage is required over an extended period.
Innovation Solution
A transdermal therapeutic system with a backing layer impermeable to the active substance, an active substance reservoir, a skin-facing barrier layer with controlled openings, and a pressure-sensitive-adhesive layer, where the backing layer protrudes beyond the reservoir to ensure controlled diffusion through the openings, allowing for adjustable release rates and prolonged adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the entire surface area of the active-substance-containing matrix lies against the skin for rapid release, then the active substance release rate is high, but the system cannot be worn for a long time without premature detachment
Solution Approach 1:
The active substance reservoir is divided into multiple separate reservoirs instead of a single continuous matrix. This segmentation reduces the total surface area in contact with the skin while maintaining the total active substance load, thereby extending wearing duration while controlling release rate through the membrane
Solution Approach 2:
A rate-controlling membrane with macropores is introduced as an intermediary layer between the active substance reservoir and the skin. This membrane controls the diffusion rate of active substance, enabling prolonged release over extended wearing periods while maintaining therapeutic efficacy
2Quantity of substance
If a low dosage of active substance is required, then the dosage is reduced, but the system may detach prematurely due to insufficient adhesion
Solution Approach 1:
The backing layer is merged with an adhesive layer to create a unified structure that provides both structural support and reliable skin adhesion. This combination ensures that even low-dosage systems maintain sufficient adhesion strength to prevent premature detachment during extended wear
3Productivity
If the barrier layer covers the entire active substance reservoir, then release is controlled, but active substance may escape via lateral edges
Solution Approach 1:
The barrier membrane is designed with non-uniform properties: it has macropores in the central region to allow controlled release while maintaining an adhesive layer at the periphery to seal the lateral edges and prevent substance escape. This local differentiation of properties solves both release control and edge leakage problems
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 system achieves controlled and prolonged release of active substances, ensuring a low dosage is maintained over time without premature detachment from the skin, utilizing a barrier layer with specific thickness and opening configurations to manage release rates effectively.
Implementation Method 1
a pressure-sensitive-adhesive layer for attachment to the skin
Implementation Method 2
Active substance release is usually effected in a membrane-controlled or diffusion- controlled manner
Implementation Method 3
a barrier layer that is facing the skin and that adjoins the active substance reservoir, is impermeable to the active substance, and has at least one opening
Data Source
AI summary
The invention relates to a transdermal therapeutic system that includes a) a backing layer which faces away from the skin, is impermeable to the active substance, and is equipped with an adhesive layer for fixing onto the skin, b) an active substance reservoir which contains at least one active substance, c) a barrier layer which faces the skin, adjoins the active substance reservoir, is impermeable to the active substance and has at least one opening, and d) a removable protective layer, in which the backing layer which is equipped with the adhesive layer projects beyond the barrier layer on all sides.