Microneedle Coating with Polyvinyl Alcohol for Sustained Drug Delivery

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Solution Overview

Problem

Conventional microneedle devices are ineffective in sustaining the effect of low molecular weight active compounds through the skin, as existing coating carriers dissolve quickly, limiting the prolonged release of drugs.

Innovation Solution

The use of polyvinyl alcohol with a saponification degree of 94.5 mol% or more as a coating carrier for microneedles, which maintains its film shape and acts as both a drug carrier and permeation route, ensuring sustained drug delivery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If conventional coating carriers are used on microneedles, then the microneedles can pierce the skin and deliver drugs, but the coating carriers dissolve quickly which limits prolonged drug release

Engineering Contradiction:
Improveduration of drug effectVSAvoidstability of coating carrier
Core Design Contradiction:
Duration of action of moving objectVSStability of the object's composition

Solution Approach 1:

The patent changes the chemical parameters of the coating carrier by using polyvinyl alcohol with high saponification degree (94.5 mol% or more) and specific molecular weight (3,000 to 300,000), which fundamentally alters the dissolution characteristics compared to conventional coating carriers, enabling sustained drug release while maintaining skin permeability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite system where polyvinyl alcohol coating carrier is combined with specific drugs (low molecular weight compounds), forming a coordinated material system where the polymer matrix provides sustained release while allowing drug permeation through microneedles into the skin

Inventive Principle:
Principle #40Composite materials

2Duration of action of stationary object

If the coating carrier maintains film shape and acts as drug carrier, then sustained drug delivery is achieved, but the complexity of selecting appropriate polymer properties increases

Engineering Contradiction:
Improveduration of sustained drug deliveryVSAvoidcomplexity of polymer selection
Core Design Contradiction:
Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The patent establishes specific parameter ranges for polyvinyl alcohol (saponification degree ≥94.5 mol%, molecular weight 3,000-300,000) that define the optimal conditions for achieving sustained drug delivery, transforming a complex material selection problem into a standardized specification set

Inventive Principle:
Principle #35Parameter changes

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

This approach enhances skin permeability and prolongs the effect of low molecular weight drugs, making it suitable for transdermal administration of compounds previously difficult to deliver effectively.

Implementation Method 1

the surface of the microneedles and/or the substrate is partly or entirely coated in fixed state with a coating carrier containing polyvinyl alcohol... which maintains its film shape and acts as both a drug carrier and permeation route

Methodology Applied
Scientific EffectPermeation: Permeation

Data Source

PatentEP2005990B1Microneedle device and transdermal administration device provided with microneedles
Publication Date: 2013.08.28 HISAMITSU PHARM CO INC
  • EP2005990B1 patent drawingFigure 1(a)~1(d)
  • EP2005990B1 patent drawingFigure 2~4
  • EP2005990B1 patent drawingFigure 5~6

AI summary

The present invention provides a microneedle device having a coating, which is effective even with a low molecular weight active compound and can sustain the effect of the drug for a long period of time, and a transdermal drug administration apparatus with microneedles. The microneedle device (5) has, on a microneedle substrate (8), a plurality of microneedles (6) that can pierce the skin, wherein the surface of the microneedles (6) and/or the microneedle substrate (8) is partly or entirely coated in fixed state with a coating carrier containing polyvinyl alcohol. The polyvinyl alcohol preferably has a hydrolysis degree of 94.5 mol% or more. Furthermore, the coating carrier can contain a drug.