Star-Shaped Microneedles for Transdermal Drug Delivery Patches
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Solution Overview
Problem
Conventional transdermal drug delivery patches with simple-shaped microneedles have limited surface area expansion, restricting the absorption efficiency of drugs.
Innovation Solution
A transdermal drug delivery patch featuring star-shaped pyramidal microneedles with radial protrusions and concave shapes between them, manufactured using a master mold and mold process involving photo-curable polymers and vacuum filtration, to enhance surface area contact with skin fluids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional simple-shaped microneedles (cone or quadrangular pyramid) are used, then manufacturing is convenient, but the surface area to volume ratio is small, limiting drug absorption efficiency
Solution Approach 1:
The microneedle surface is segmented into multiple protrusions (3-20 radial protrusions) rather than being a smooth surface. This segmentation increases the surface area to volume ratio by creating additional contact interfaces with skin fluids, while the modular protrusion structure can be integrated into conventional manufacturing processes through mold design.
Solution Approach 2:
The microneedle geometry transitions from simple 2D base shapes (cone, quadrangular pyramid) to a 3D star-shaped pyramid with radial protrusions extending in multiple directions. This dimensional complexity increases the surface area without proportionally increasing volume, optimizing the surface area to volume ratio for enhanced drug absorption.
2Productivity
If microneedle surface area is increased, then drug absorption efficiency improves, but manufacturing complexity increases
Solution Approach 1:
The invention optimizes specific geometric parameters of the star-shaped pyramid, including the number of protrusions (3-20), protrusion height (0.1-0.5mm), and inter-protrusion spacing. These parameter variations allow tuning of surface area to volume ratio while maintaining manufacturability through standardized mold designs and material properties.
Solution Approach 2:
The microneedle employs asymmetric star-shaped pyramid geometry with radial protrusions rather than symmetric simple shapes. This asymmetric design maximizes surface area exposure to skin fluids from multiple directions, enhancing drug absorption efficiency while the regular radial pattern maintains compatibility with rotational molding processes.
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 star-shaped microneedles increase the surface area in contact with skin fluids, leading to faster drug absorption and quicker biodegradable polymer dissolution, thereby enhancing drug absorption efficiency.
Implementation Method 1
forming a photo-curable polymer layer on a transparent plate; disposing a grayscale mask between a light source and the transparent plate; and irradiating light to the photo-curable polymer layer through the grayscale mask to cure a part of the photo-curable polymer layer
Implementation Method 2
a vacuum pump connected to the vacuum chamber may be operated, and a negative pressure in a single direction may be applied to the biodegradable polymer solution and the material solution through the mold and the vacuum filter to remove microbubbles included in the biodegradable polymer solution and the material solution
Implementation Method 3
a microneedle made of a biodegradable polymer loaded with a drug... allow a drug to decompose by body fluids and to be absorbed into the body
Data Source
AI summary
A transdermal drug delivery patch includes a flexible base layer, and a plurality of microneedles disposed at one surface of the base layer and including a biodegradable polymer and a drug. Each of a plurality of microneedles is formed as a star-shaped pyramid including a plurality of protrusions extending in a radial direction, and a concave shape is formed between two protrusions adjacent along a circumferential direction among a plurality of protrusions.