Sterile Adhesive Patch Assembly for Wearable Injectors

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Solution Overview

Problem

Drug delivery devices face issues with bacterial contamination on adhesive surfaces and exposure to harmful light, particularly for viscous drugs and photo-sensitive medications, which compromise sterility and effectiveness.

Innovation Solution

A drug delivery device with a bacteria-impermeable adhesive patch and sterility margin, combined with a polarized viewing window to protect drugs from light, ensuring sterility and visibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the adhesive patch is made with exposed edge surfaces for attachment, then the device can be securely attached to the patient, but bacteria and harmful microorganisms can adhere to the exposed surfaces and transfer to the patient

Engineering Contradiction:
Improveattachment strengthVSAvoidsterility
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The adhesive patch is divided into multiple functional layers: a sterile adhesive layer, a non-sterile border layer, and a release liner. This segmentation allows the adhesive surface to be covered and protected until use, preventing bacterial contamination while maintaining attachment capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A release liner acts as an intermediary barrier between the adhesive patch and the environment during storage and transport. This liner prevents bacteria from adhering to the adhesive surface while allowing the adhesive to function when the liner is removed at the point of use.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of information

If a viewing window is provided to inspect the drug, then the user can determine whether delivery is complete, but photo-sensitive drugs are damaged by exposure to visible light

Engineering Contradiction:
Improvedrug inspection capabilityVSAvoidlight exposure damage
Core Design Contradiction:
Loss of informationVSObject-affected harmful factors

Solution Approach 1:

The viewing window incorporates a polarized filter that selectively blocks harmful polarized light while allowing sufficient visible light transmission for drug inspection. This creates a localized optical property that protects the photo-sensitive drug in that specific area while maintaining transparency for observation.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The polarized filter changes the polarization state of light passing through the viewing window, blocking harmful polarized light wavelengths while allowing non-polarized or differently polarized light to pass, thereby protecting the drug while enabling inspection.

Inventive Principle:
Principle #35Parameter changes

3Shape

If the adhesive patch perimeter is made thin for flexibility, then the device can conform to the patient's body, but the edge surface becomes more susceptible to bacterial adhesion

Engineering Contradiction:
ImproveflexibilityVSAvoidsterility
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

The adhesive patch perimeter is segmented into a thin flexible adhesive region and a thicker protective border region. The border layer maintains sterility by covering the edge surface, while the thin adhesive region provides flexibility for body conformance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The adhesive patch uses thin film construction with a flexible adhesive layer that can conform to curved body surfaces, while incorporating a protective border film that prevents bacterial adhesion on the edge surfaces during storage and transport.

Inventive Principle:
Principle #30Flexible shells and thin films

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 effectively prevents bacterial contamination and protects drugs from light, maintaining sterility and visibility during drug delivery.

Implementation Method 1

a bacteria impermeable lower liner on the lower surface and a bacteria impermeable sterility margin surrounding the edge surface

Methodology Applied
Scientific EffectBacteria impermeability: Filter (physical)

Implementation Method 2

a polarized viewing window to protect drugs from light

Methodology Applied
Scientific EffectPolarization: Polarisation

Implementation Method 3

a polarized viewing window to protect drugs from light

Methodology Applied
Scientific EffectOptical filtering: Filter (optical)

Data Source

PatentEP3668567B1Wearable injector with sterile adhesive patch
Publication Date: 2026.02.18 AMGEN INC
  • EP3668567B1 patent drawingFigure 1
  • EP3668567B1 patent drawingFigure 2
  • EP3668567B1 patent drawingFigure 3A~3B

AI summary

An adhesive patch for a drug delivery device with a bacteria impermeable sterility margin surrounding an edge surface of the adhesive patch is disclosed, as well as a drug delivery device fixed to such an adhesive patch and a method of assembling a drug delivery device with such an adhesive patch. In some arrangements, the sterility margin is attached to or integral with a lower liner on a lower surface of the adhesive patch. In other arrangements, the sterility margin is attached to or integral with an upper liner on an upper surface of the adhesive patch.