Microprojection Injection Needle Structure to Reduce Wheal Formation

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Solution Overview

Problem

Existing intradermal injection methods face challenges in efficiently administering liquids, such as drugs, due to the formation of wheals that can hinder liquid distribution and absorption.

Innovation Solution

The injection needle features fine projections, including a first projection with a conical shape and a second projection without an opening, arranged in specific regions to minimize wheal formation and enhance liquid distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If intradermal injection is performed using conventional methods, then liquid administration is achieved, but wheal formation occurs that hinders liquid distribution and absorption

Engineering Contradiction:

Improveliquid distribution efficiencyVSAvoidwheal formation

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The injection needle is divided into multiple fine projections (first projections with openings and second projections without openings) arranged in specific regions. This segmentation allows the liquid to be distributed through multiple small channels rather than a single large channel, reducing wheal formation while improving liquid distribution efficiency throughout the intradermal space.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the injection needle have different properties: the first region contains first projections with openings for liquid ejection, while the second region contains second projections without openings that provide structural support and control insertion depth. This local differentiation optimizes both liquid distribution and minimizes harmful wheal formation.

Inventive Principle:

Principle #3Local quality

2Productivity

If multiple projections are used to improve liquid distribution, then injection efficiency increases, but device complexity increases

Engineering Contradiction:

Improveinjection efficiencyVSAvoidprojection arrangement

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

Multiple functional elements (liquid-ejecting projections and support projections) are merged into a single integrated needle structure formed from a sheet base portion. This combining approach maintains high injection efficiency through multiple projections while avoiding the complexity of assembling separate components, as the entire structure can be manufactured as one piece using techniques like embossing or molding.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS20250288786A1Injection needle

Publication Date: 2025.09.18 KAO CORP

AI summary

An injection needle can include first and second projections; wherein the first projection and the second projection each can be regarded as fine and protrude from a sheet base portion, the first projection can have a conical shape and can include an opening in a distal end portion thereof, the second projection does not include an opening in a distal end portion thereof, and the first projection and the second projection each have a protruding height of 5000 μm or less. The injection needle can include a first region and a second region in plan view; wherein first region includes one or two or more first projections; the second region includes two or more second projections; and the second region surrounds the first region or the second regions sandwich the first region.