Surface-Modified Microsphere Microneedles for Sustained Drug Release

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Solution Overview

Problem

Existing microneedles face challenges with reduced residence time in the body and inadequate sustained-release effects, particularly for diseases requiring continuous drug administration.

Innovation Solution

Microneedles comprising surface-modified microspheres with a dimple structure, formed using a solvent evaporation method, which are biodegradable and encapsulate drugs, providing improved residence time and sustained-release effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If soluble microneedles based on biodegradable polymer are used, then drug delivery into skin is achieved, but residence time in body is reduced due to skin elasticity causing active ingredient escape

Engineering Contradiction:
Improveresidence time in bodyVSAvoidsustained-release effect
Core Design Contradiction:
Duration of action of moving objectVSReliability

Solution Approach 1:

The invention employs microspheres with a spherical geometry and specifically introduces surface dimples or irregularities on the microsphere surface. This spherical shape with surface curvature modifications enables the microspheres to better resist skin elasticity forces after microneedle dissolution, preventing active ingredient escape and thereby extending residence time in the body while maintaining reliable sustained-release效果

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention modifies physical parameters of the microsphere including surface morphology (adding dimples or irregularities), size distribution, and material composition. These parameter changes enhance the microsphere's mechanical resistance to skin elasticity and control drug release kinetics, achieving both extended residence time and reliable sustained-release effect

Inventive Principle:
Principle #35Parameter changes

2Duration of action of moving object

If conventional smooth microspheres are used, then manufacturing is simpler, but drug residence time and sustained-release effect are insufficient

Engineering Contradiction:
Improveresidence time in bodyVSAvoidmicrosphere preparation complexity
Core Design Contradiction:
Duration of action of moving objectVSEase of manufacture

Solution Approach 1:

The invention incorporates surface modification (dimple formation) into the microsphere manufacturing process itself, rather than as a separate post-processing step. The preliminary action of adding surfactants or modifying emulsion conditions during microsphere formation automatically creates the desired surface dimples, achieving both improved residence time and manufacturing feasibility without significant additional complexity

Inventive Principle:
Principle #10Preliminary action

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 surface-modified microspheres enhance drug residence time in the body, ensuring effective and prolonged drug delivery for conditions like atopic dermatitis and acne.

Implementation Method 1

forming an O/W emulsion by mixing the oil phase with a water phase... and obtaining surface-modified microspheres by evaporating the solvent from the O/W emulsion

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 2

The biodegradable microsphere has a predetermined period of degradation and disappearance in the body based on the degradation mechanism and rate of its main component, a biodegradable polymer. The release of the encapsulated drug within the microsphere occurs over a certain period of time depending on the biodegradation rate of the polymer

Methodology Applied
Scientific EffectBiodegradation: Decomposition (biological)

Data Source

PatentEP4252740B1Microneedle including surface-modified microspheres and manufacturing method therefor
Publication Date: 2025.08.06 SMALLLAB
  • EP4252740B1 patent drawingFigure 1A
  • EP4252740B1 patent drawingFigure 1B
  • EP4252740B1 patent drawingFigure 2

AI summary

Microneedles comprising surface-modified microspheres which exhibit improved residence time in body and superior sustained-release effect, and are suitable for the treatment of diseases requiring continuous drug administration due, and a method of preparing the same, are disclosed herein. Microneedles comprising surface-modified microspheres containing a drug according to the present invention exhibit improved residence time in the body and an superior sustained-release effects, and are therefore useful for treatment of conditions and diseases requiring continuous drug administration.