Temperature-Responsive Sealing Layer for Transdermal Patch Stability
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Solution Overview
Problem
Existing dermal and transdermal therapeutic systems face issues with storage stability, leakage, and uneven release of active ingredients due to adhesive layer instability and oxygen permeability, limiting the use of potent drugs with narrow therapeutic indices.
Innovation Solution
A dermal or transdermal system with a reservoir containing an active ingredient and an active ingredient-permeable membrane, where a sealing layer is impermeable at skin temperature (around 32°C) and becomes permeable above it, eliminating the need for a skin-side adhesive layer and enhancing stability and controlled release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a skin-side adhesive layer is used to secure the reservoir system to the skin, then the system can be applied and maintained in place, but the adhesive layer becomes unstable when in contact with liquids, leading to storage instability and potential leakage
Solution Approach 1:
The patent removes the skin-side adhesive layer entirely from the reservoir system. Instead, the system uses a temperature-responsive sealing layer that provides both secure attachment to the skin and maintains stability during storage, eliminating the conflicting requirements of the traditional adhesive layer.
Solution Approach 2:
The sealing layer's permeability and adhesive properties change in response to temperature changes. At storage temperatures, the sealing layer remains impermeable and stable, while at skin temperature it becomes permeable and adheres to the skin, providing both stability and functionality without requiring a separate adhesive layer.
2Quantity of substance
If a skin-side adhesive layer is used to secure the system, then the system can be applied to the skin, but the adhesive layer creates an additional barrier that limits active ingredient permeation
Solution Approach 1:
The patent combines the functions of the adhesive layer and the sealing layer into a single temperature-responsive sealing layer. This eliminates the additional barrier effect of a separate adhesive layer while maintaining all necessary functions of skin attachment and active ingredient delivery.
3Duration of action of stationary object
If a traditional reservoir system with adhesive layer is used, then the system can be applied to the skin, but the adhesive layer allows oxygen to enter the reservoir, causing active ingredient degradation and shortening shelf life
Solution Approach 1:
The sealing layer's oxygen permeability is controlled by temperature. At storage temperatures below the transition point, the sealing layer maintains an impermeable state that prevents oxygen ingress and protects the active ingredient. When applied to the skin, the temperature increase triggers a phase change that makes the sealing layer permeable to the active ingredient while maintaining oxygen barrier properties.
4Reliability
If a membrane permeable to active ingredient is used, then the active ingredient can be delivered through the skin, but the system lacks sufficient storage stability and may leak
Solution Approach 1:
The sealing layer undergoes a temperature-induced phase transition that switches its permeability properties. At storage temperatures, the sealing layer is in an impermeable phase that prevents leakage and ensures stability. When exposed to skin temperature, the phase transition occurs, making the sealing layer permeable to the active ingredient and enabling controlled delivery through the skin.
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
This design improves storage stability, allows for higher doses of active ingredients, prevents initial excessive release, and extends the shelf life by maintaining the system's integrity and controlled release kinetics.
Implementation Method 1
a sealing layer, the sealing layer being impermeable to the at least one active ingredient at a temperature below the skin temperature and at a temperature of skin temperature or above is permeable
Implementation Method 2
an active ingredient-permeable membrane delimiting the active ingredient reservoir
Implementation Method 3
transfer of active ingredients into the blood vessels, bypassing the gastrointestinal tract
Data Source
Figure 1
AI summary
Disclosed is a dermal or transdermal therapeutic system (100) comprising a reservoir (5) that contains at least one active substance (4), an active substance-permeable membrane (3) which delimits the active substance reservoir, and a closing layer (2). The closing layer (2) is impermeable to the at least one active substance at a temperature lying below the skin temperature while being permeable thereto at the skin temperature or above.