# A Dissolving Microneedle Design for Poorly Water-Soluble Drugs for Enhanced Skin Permeation and Transdermal Delivery Fabricated Using 3D Printing

## TL;DR

This paper presents a 3D-printed dissolving microneedle design that improves drug delivery through the skin, especially for poorly water-soluble drugs.

## Contribution

A novel 3D-printed star-shaped microneedle design is introduced, optimized for enhanced drug permeation and mechanical strength.

## Key findings

- Star-type microneedles achieved the highest drug permeation (86.9 ± 9.9%) compared to other designs.
- Printing at 45° improved tip sharpness and insertion efficiency.
- The star design showed 100% penetration rate and superior mechanical strength in ex vivo tests.

## Abstract

Microneedles (MNs) offer a transformative platform for transdermal drug delivery, though balancing structural precision with mechanical robustness remains challenging. This study utilized SLA 3D printing to fabricate high-resolution MN masters, systematically evaluating printing angles (0° to 60°) and aspect ratios to optimize fidelity. A 45° printing angle was found to significantly enhance tip sharpness and insertion efficiency. These optimized structures served as templates for flurbiprofen (FLU)-loaded dissolving MNs (DMNs) fabricated via a bilayered casting method. We investigated the impact of geometric architectures—conical, pyramidal, and star-type—on functional performance. Mechanical testing using Parafilm® M and ex vivo rat skin revealed that the star-type design, possessing the highest vertex count, exhibited superior strength and a 100% penetration rate by effectively concentrating stress at tip edges. Consequently, star-type DMNs achieved the highest cumulative drug permeation (86.9 ± 9.9% in 12 h), outperforming pyramidal (77.8 ± 9.0%) and conical (64.4 ± 10.2%) designs. These findings underscore geometric design as a critical determinant of clinical efficacy, providing a robust framework for precision manufacturing of task-specific MNs for poorly soluble drugs.