Transdermal Sheet With Thickened Edge For Impact Resistance
Solution Overview
Problem
Transdermal absorption sheets with needle-like protrusions face challenges in ensuring strength during puncture to effectively deliver drugs into the skin, as existing designs either lack durability or suffer from skin deviation and needle bending due to inadequate structural support.
Innovation Solution
A transdermal absorption sheet with a polymer resin composition featuring a center portion with a lower average thickness and an outer edge portion with a gradually increasing thickness, providing enhanced strength and preventing skin deviation by distributing puncture stress evenly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the resin polymer is made thick to endure impact at puncture, then the strength against impact is improved, but the drying time becomes longer
Solution Approach 1:
The patent applies local quality by creating a thickness portion in the outer edge region of the sheet portion, making this specific area thicker than the center portion. This localized thickening provides impact resistance where needed (at the edges during puncture) while keeping the overall sheet thin for rapid drying. The thickness portion has a maximum thickness of 15-5000 μm, which is larger than the average thickness of the center portion (10-500 μm).
Solution Approach 2:
The patent segments the sheet portion into distinct regions with different thickness characteristics: a center portion with average thickness and an outer edge portion with a thickness portion. This segmentation allows each region to serve its specific function - the center for drug delivery and the outer edge for impact resistance - thereby resolving the contradiction between overall thickness requirements.
2Strength
If the support portion is curved to provide structural support, then the strength is improved, but skin deviation occurs causing needle bending
Solution Approach 1:
The patent applies local quality by providing structural support only in the outer edge region through the thickness portion, rather than curving the entire support portion. This localized thickening reinforces the edges to prevent skin deviation during puncture while keeping the center portion flat, ensuring the needle-like protruding portions remain perpendicular to the skin surface for accurate drug delivery.
3Loss of time
If the sheet is made thin to reduce drying time, then the drying time is shortened, but the strength against impact during puncture is reduced
Solution Approach 1:
The patent resolves this contradiction by making only the outer edge region thicker while keeping the center portion thin. The thickness portion in the outer edge has maximum thickness of 15-5000 μm, providing impact resistance, while the center portion maintains average thickness of 10-500 μm for rapid drying. This selective thickening allows the sheet to dry quickly while still withstanding puncture impact forces.
Data Source
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Figure 3
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AI summary
Provided is a transdermal absorption sheet capable of improving strength against impact at the time of puncture. A transdermal absorption sheet 100 includes a sheet portion 116 and a plurality of needle-like protruding portions 110 arranged on a first principal surface of the sheet portion 116, in which the sheet portion 116 has a center portion 116A which is a region in which the plurality of needle-like protruding portions 110 are formed, and an outer edge portion 116B which is a region from the center portion 116A to an end portion 116C, and a maximum thickness TMax of a thickness portion 116D of the outer edge portion 116B is larger than an average thickness TAve of the center portion 116A.