Dissolving Microneedle Structure for Stronger Skin Penetration

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Solution Overview

Problem

Existing microstructures made from biodegradable polymers like low-molecular weight hyaluronic acid and carboxymethyl cellulose (CMC) suffer from mechanical weakness, leading to bending or breaking during skin penetration, and have suboptimal tip angles and diameters that limit effective delivery of ingredients.

Innovation Solution

The development of microstructures with optimized aspect ratios, controlled tip angles, and double or triple structures, combined with a hexagonal arrangement, enhances mechanical strength and facilitates skin penetration, ensuring stable delivery of ingredients.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If microneedles are used for transdermal delivery, then penetration capability is improved, but mechanical strength and stability deteriorate

Engineering Contradiction:

Improvepenetration capabilityVSAvoidmechanical strength

Core Design Contradiction:

SpeedVSStrength

Solution Approach 1:

The device segments the microneedle array into modular units that can be independently handled and applied. Each microneedle is a discrete element within the array, allowing for controlled deployment while maintaining overall structural integrity through the array configuration.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The microneedles are formed from hydrogel composite materials that combine water-soluble polymers with reinforcing agents. This composite structure provides both the sharpness needed for skin penetration and the mechanical strength required to withstand application forces without breaking.

Inventive Principle:

Principle #40Composite materials

2Speed

If microneedles are used for transdermal delivery, then penetration capability is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvepenetration capabilityVSAvoidmanufacturing complexity

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The manufacturing process utilizes changes in physical parameters, particularly temperature and solvent evaporation, to transform the hydrogel precursor solution into solid microneedles. This phase transition approach simplifies fabrication by using self-organizing gelation rather than complex mechanical forming processes.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The hydrogel material exhibits self-organizing properties during solvent evaporation, automatically forming the microneedle structure without requiring complex molds or assembly steps. The material itself performs the shaping function through controlled phase separation and gelation.

Inventive Principle:

Principle #25Self-service

3Productivity

If microneedles are used for transdermal delivery, then drug delivery effectiveness is improved, but structural stability deteriorates

Engineering Contradiction:

Improvedrug delivery effectivenessVSAvoidstructural stability

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The microneedles transition from a stable solid state during storage and application to a dynamic dissolving state upon skin contact. This dynamic behavior allows the structure to maintain integrity until deployment, then automatically transform to release the therapeutic payload through controlled dissolution.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The microneedle structure is designed to be temporarily discarded after use, dissolving into the skin to deliver the drug. The hydrogel material is recovered by the body through natural metabolic processes, eliminating the need for removal and reducing structural stability requirements post-delivery.

Inventive Principle:

Principle #34Discarding and recovering

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 optimized microstructures achieve higher penetration rates and absorption rates of useful ingredients into the skin, with mechanical strengths of 80% or higher, and uniform pressure distribution across the skin surface.

Implementation Method 1

microneedles have been investigated as a means of penetrating the stratum corneum

Methodology Applied

Scientific EffectMechanical penetration: Mechanical Force

Implementation Method 2

method for preparing percutaneous absorption-enhancing microstructure

Methodology Applied

Scientific EffectPercutaneous absorption: Absorption (physical)

Data Source

PatentEP3398645B1Method for preparing a microstructure for percutaneous absorption

Publication Date: 2026.05.13 ENDO DERMA CO LTD

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AI summary

The present invention relates to a microstructure including a biocompatible polymer or an adhesive and to a method for manufacturing the same. The present inventors optimized the aspect ratio according to the type of each microstructure, thereby ensuring the optimal tip angle and the diameter range for skin penetration. Especially, the B-type to D-type microstructures of the present invention minimize the penetration resistance due to skin elasticity at the time of skin attachment, thereby increasing the penetration rate of the structures (60% or higher) and the absorption rate of useful ingredients into the skin. In addition, the D-type microstructure of the present invention maximizes the mechanical strength of the structure by applying a triple structure, and thus can easily penetrate the skin. When the plurality of microstructures are arranged in a hexagonal arrangement type, a uniform pressure can be transmitted to the whole microstructures on the skin.