Conformable Barrier Sheet for Transdermal Drug Delivery
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Solution Overview
Problem
Conventional barrier sheets for packaging and transdermal drug delivery devices lack flexibility and maintain barrier properties when stretched, often resulting in loss of moisture vapor transmission resistance.
Innovation Solution
A conformable barrier sheet comprising a polymeric film with high tensile elongation, a planarization layer, and a plasma-deposited amorphous glass layer comprising silicon, carbon, and hydrogen, which maintains moisture vapor transmission resistance after undergoing tensile elongation within 2% to 20%.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional barrier sheet uses a polyester substrate with a barrier layer to maintain moisture vapor transmission resistance, then the barrier properties are maintained, but the flexibility and stretchability are insufficient
Solution Approach 1:
The patent uses a polymeric film substrate that is inherently flexible and capable of stretching, replacing the conventional rigid polyester substrate. This allows the barrier sheet to conform to curved or irregular surfaces while maintaining its moisture vapor transmission resistance through the plasma-deposited barrier layer.
Solution Approach 2:
The patent creates a composite structure combining a flexible polymeric film substrate with a plasma-deposited amorphous glass-like carbon barrier layer. This composite material achieves both flexibility from the polymer and moisture vapor transmission resistance from the barrier layer, resolving the contradiction between these two properties.
2Adaptability or versatility
If a barrier sheet is stretched during processing or use to improve conformability, then the flexibility increases, but the moisture vapor transmission resistance is lost
Solution Approach 1:
The patent employs a dynamic substrate made of elastomeric or thermoplastic polymeric film that can elastically deform during stretching and then return to its original state. This dynamic behavior allows the barrier sheet to be conformable during application while maintaining barrier integrity during use, as the flexible substrate accommodates dimensional changes without compromising the barrier layer's performance.
Solution Approach 2:
The patent utilizes polymeric films with specific material parameters (elastomeric or thermoplastic properties) that allow significant tensile elongation (at least 2 fold greater than PET film) while maintaining structural integrity. This parameter selection enables the substrate to undergo stretching without causing cracks or delamination in the barrier layer, thus preserving moisture vapor transmission resistance.
3Stability of the object's composition
If a polyethylene terephthalate film is used as substrate, then the heat stability and dimensional stability are achieved, but the tensile elongation is insufficient for conformable applications
Solution Approach 1:
The patent changes the material parameters of the substrate by selecting polymeric films with elastomeric or thermoplastic properties instead of conventional rigid polyester. These materials exhibit at least 2 fold greater tensile elongation compared to polyethylene terephthalate film, enabling significant stretching while maintaining sufficient dimensional stability through the plasma-deposited barrier layer.
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 solution provides a flexible barrier sheet that maintains moisture vapor transmission resistance during stretching, ensuring a stable environment for moisture-sensitive products and drugs, suitable for use in transdermal drug delivery devices.
Implementation Method 1
a plasma-deposited amorphous glass layer comprising silicon, carbon, and hydrogen; wherein the planarization layer is disposed on the polymeric film, the amorphous glass layer is deposited on the planarization layer
Data Source
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Figure 3
AI summary
A conformable barrier sheet comprising a polymeric film having a tensile elongation at least 2 fold greater than a polyethylene terephthalate film of equal dimensions and under an equal load; a planarization layer; and a plasma-deposited amorphous glass layer comprising silicon, carbon, and hydrogen; wherein the planarization layer is disposed on the polymeric film, the amorphous glass layer is deposited on the planarization layer, and wherein the barrier sheet is sufficiently conformable that after undergoing a tensile elongation within the range of more than 2 % to 20 %, the barrier sheet has a moisture vapor transmission rate essentially unchanged compared with prior to being elongated, a method of making the conformable barrier sheet, a transdermal device comprising the conformable barrier sheet, a method of delivering a drug to a mammal using the device, and a method of protecting an article using the conformable barrier sheet are provided.