Hollow Microneedle Array for Rapid Intradermal Infusion

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Solution Overview

Problem

Traditional transdermal drug delivery methods, including microneedle arrays, face limitations in delivering small molecule salts and therapeutic proteins due to skin barriers, and often result in low delivery rates and pain, making them unsuitable for high-volume or rapid drug administration.

Innovation Solution

A hollow microneedle array with 10 to 30 microneedles spaced 2 mm apart, having a length of 500-750 um and a 20-50 um² cross-sectional area, capable of delivering up to 1mL of fluid at a rate of 500 uL/min with minimal pain, by using a substrate made of medical-grade polycarbonate and an adhesive backing for secure skin attachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If microneedle arrays are used for transdermal drug delivery, then patient comfort is improved and needle anxiety is reduced, but delivery rate is limited to less than 30mcL/hour

Engineering Contradiction:
Improvepatient comfortVSAvoiddelivery rate
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The device divides the delivery function across multiple hollow microneedles (10-30 needles) working in parallel, allowing cumulative flow rates exceeding 30mcL/hour while maintaining the comfort benefits of microneedle technology

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes key parameters including microneedle spacing (2mm apart), needle dimensions (100um-1mm length), and hollow channel geometry to optimize both comfort and delivery rate simultaneously

Inventive Principle:
Principle #35Parameter changes

2Productivity

If infusion rate is increased to deliver larger volumes, then delivery productivity is improved, but pain increases significantly

Engineering Contradiction:
Improveinfusion rateVSAvoidpain
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The infusion burden is distributed across 10-30 microneedles working in parallel, allowing high total flow rates without concentrating excessive pressure or fluid velocity at any single needle site, thereby avoiding pain

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Optimized microneedle spacing of 2mm and hollow channel dimensions create favorable flow dynamics that enable rapid infusion without generating painful pressure concentrations

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If traditional transdermal patches are used, then non-invasive delivery is achieved, but delivery is limited to lipophilic molecules that can be absorbed through skin

Engineering Contradiction:
Improvenon-invasive deliveryVSAvoiddrug compatibility
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

Hollow microneedles serve as an intermediary structure that creates controlled micro-channels through the skin barrier, enabling delivery of hydrophilic and macromolecular drugs that cannot pass through intact skin or traditional transdermal patches

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The hollow microneedle array creates temporary porous pathways through the skin, allowing passage of diverse drug formulations including proteins and salts that are incompatible with traditional transdermal delivery

Inventive Principle:
Principle #31Porous materials

4Productivity

If microneedle density is increased to improve delivery volume, then productivity is improved, but pain and back pressure increase

Engineering Contradiction:
Improvedelivery volumeVSAvoidback pressure
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The invention identifies an optimal microneedle spacing parameter (2mm) that maximizes delivery volume while minimizing back pressure and pain, demonstrating that neither maximum density nor minimum density is optimal

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2355887B1Hollow microneedle array
Publication Date: 2017.08.02 3M INNOVATIVE PROPERTIES CO
  • EP2355887B1 patent drawingFigure 1A~1B
  • EP2355887B1 patent drawingFigure 2A~2B
  • EP2355887B1 patent drawingFigure 3A~3B

AI summary

Rapid, high-volume, intradermal infusion with minimal pain, is achived by applying an array of 10 to 30 hollow microneedles having a length of greater than 100um to less than 1mm into the skin of a patient, with a microneedle spacing of no less than 1.5mm on average between adjacent microneedles, and pumping greater than 200uL of fluid through the hollow microneedles at a rate of greater than 20 uL/min.