Microneedle Projection Area-to-Length Ratio for Skin Piercing
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Solution Overview
Problem
Existing microneedle technologies face challenges in efficiently piercing the skin due to skin deformation and difficulty in maintaining the sharpness of resin-based projections, which affects the delivery of liquid drugs.
Innovation Solution
A microneedle design featuring a projection with a through hole and a tubular member having a supporting surface with a specific area-to-length ratio (2.1 to 10.5) to minimize skin deformation and enhance piercing efficiency, integrated with a flange for secure attachment to syringe barrels and a recess for easy handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a resin-based projection is used for microneedle fabrication, then ease of manufacture is improved, but difficulty in maintaining sharpness and piercing efficiency worsens
Solution Approach 1:
The patent optimizes the geometric parameters of the projection, specifically setting the length H and supporting surface area S within specific ranges (2.1 ≤ S/H ≤ 10.5). This parameter optimization ensures that resin-based projections maintain both manufacturability and sufficient sharpness for effective skin piercing, resolving the contradiction between ease of manufacture and piercing reliability.
2Stability of the object's composition
If the supporting surface area is increased, then stability during drug administration is improved, but skin deformation increases
Solution Approach 1:
The patent establishes an optimal range for the supporting surface area S relative to projection length H (2.1 ≤ S/H ≤ 10.5). This optimized ratio provides sufficient stability to prevent skin deformation and ensure proper drug delivery, while avoiding excessive surface area that would cause harmful skin deformation. The parameter optimization simultaneously addresses both stability and minimization of harmful effects.
3Productivity
If the projection length is increased to reach deeper skin layers, then drug delivery effectiveness is improved, but skin piercing difficulty increases
Solution Approach 1:
The patent optimizes the projection length H within a specific range that balances piercing ease and drug delivery effectiveness. By controlling H alongside the supporting surface area S (maintaining 2.1 ≤ S/H ≤ 10.5), the design ensures the projection is long enough to reach antigen-presenting cells in the dermis layer while remaining short enough to avoid nerve cells and maintain piercing feasibility.
Data Source
AI summary
A microneedle including a projection having a through hole formed in the projection in a direction that the projection extends, and a tubular member having an end surface configured to support the projection when the end surface is pressed against a skin and a fluid is supplied through the through hole of the projection to the skin. The projection has a length H along the direction that the projection extends and the supporting surface has an area S such that a ratio of S/H is in a range of from 2.1 to 10.5.