Transdermal Precursor With Folded Liner For Drug Stability

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Solution Overview

Problem

Transdermal absorption preparations face challenges in maintaining drug stability and skin permeability due to interactions between drugs and penetration enhancers, leading to inconsistent skin permeability and crystallization issues during storage.

Innovation Solution

A transdermal absorption preparation precursor is designed with a release liner featuring valley and mountain fold parts, allowing separate storage of drug and adhesive layers, which are easily laminated to prevent positional deviations and maintain drug stability, enabling easy construction of a laminate structure for application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a transdermal absorption preparation contains both drug and penetration enhancer in the same layer, then skin permeability is enhanced, but drug stability deteriorates due to reaction between penetration enhancer and drug during storage

Engineering Contradiction:
Improvedrug stabilityVSAvoidskin permeability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The preparation is divided into separate layers: a first layer containing the drug and a second layer containing the penetration enhancer. This segmentation prevents direct contact between the drug and penetration enhancer during storage, maintaining drug stability while allowing skin permeability enhancement when the layers are combined for application.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A release liner with valley fold and mountain fold parts serves as an intermediary structure that holds the drug-containing layer and penetration enhancer-containing layer separately during storage, then facilitates their controlled combination during application, enabling both drug stability and skin permeability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If multiple layers are separately preserved and assembled by user, then drug stability is maintained, but device complexity increases due to multiple components

Engineering Contradiction:
Improvedrug stabilityVSAvoidnumber of layers
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple functionally separate layers (drug-containing layer, penetration enhancer-containing layer, release liner) are merged into a single integrated precursor structure where all layers are pre-positioned on the release liner with fold lines, simplifying storage and assembly while maintaining drug stability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The release liner is pre-formed with valley fold and mountain fold parts during manufacturing, establishing the correct spatial arrangement of layers before use. This preliminary structuring eliminates the need for complex user assembly while maintaining the benefits of separate layer preservation.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If layers are laminated without precise positioning, then ease of assembly is improved, but manufacturing precision deteriorates due to positional deviation

Engineering Contradiction:
Improveassembly easeVSAvoidlamination position accuracy
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The release liner incorporates asymmetric fold line patterns (valley fold and mountain fold parts at specific positions) that create a unique, non-reversible folding sequence. This asymmetric design guides the user through a single correct assembly path, ensuring precise layer positioning while maintaining simple user operation.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The release liner includes visual indicators (colored regions or patterns) that change or become visible during the folding process, providing real-time feedback to the user about the correct folding state and layer alignment, thereby ensuring manufacturing precision without complicating the assembly process.

Inventive Principle:
Principle #32Color changes

Data Source

PatentEP3395337B1Transdermal absorption preparation precursor
Publication Date: 2023.06.14 NITTO DENKO CORP
  • EP3395337B1 patent drawingFigure 1~1(D)
  • EP3395337B1 patent drawingFigure 2~2(E)
  • EP3395337B1 patent drawingFigure 3~3(E)

AI summary

A transdermal absorption preparation precursor 50 containing a release liner 10 containing one first valley fold part 1, one or two first mountain fold parts 2, and a first base line L1 and a second base line L2 on one side and the other side apart from the first valley fold part 1 as a line of demarcation and at an approximately equal distance from the first valley fold part 1, wherein at least one of the first base line L1 and the second base line L2 is a fold line of the first mountain fold part 2, and a drug-containing layer 3 having a center line laid on the first base line L1 and an adhesive layer 4 having a center line laid on the second base line L2 on the release liner 10.