Mikayla Rahman
BME PhD Defense Presentation

Date: 2025-08-19
Time: 1:00 PM-3:00 PM
Location / Meeting Link: IBB 1128 Suddath Room / https://gatech.zoom.us/j/94397270587?pwd=BpNGLgOPnlWIn46XvKlYfDDePg2wen.1

Committee Members:
Mark Prausnitz, PhD (Advisor); Blair Brettmann, PhD; James Dahlman, PhD; Steven Schwendeman, PhD; Johnna Temenoff, PhD


Title: Microneedle Patch Fabrication via Melt Casting for Sustained Contraceptive Delivery

Abstract:
In 2015-2019, there were ~121 million unintended pregnancies worldwide, representing 48% of all pregnancies. Despite a large variety of both hormonal and non-hormonal contraceptive methods currently available, unintended pregnancies still occur due to lack of user compliance, effectiveness, and accessibility. Microneedle patches may provide an improved contraceptive option, as these patches contain micron-scale needles on the surface which can be used for sustained drug delivery, while being painless, self-administrable and minimally invasive. Once applied to the skin, the microneedles which are composed of a biodegradable polymer encapsulating the contraceptive, detach from the patch backing and release the payload continuously as the polymer slowly degrades. Previous studies have demonstrated the effectiveness of microneedle patches releasing levonorgestrel, a commonly used contraceptive, at a sustained rate, but little research has investigated new melt-based fabrication techniques which do not use organic solvents, are designed to reduce manufacturing times and increase safety. To eliminate the time needed for solvent evaporation that is usually part of conventional fabrication processes, we explored three melt-casting approaches to form microneedles. For my first aim, I explored the parameters influencing multiple melt-casting approaches for a biodegradable matrix microneedle patch for sustained contraceptive delivery. I screened them experimentally for their capabilities to form sharp microneedles with the polymer and LNG confined to only the microneedles. Microneedle patches were characterized for their composition, skin insertion, and in vitro release profile. This study showed that an integrated approach resulted in a melt-cast MNP encapsulating LNG and a water-soluble backing with decreased porosity, good skin puncture, and sustained drug release for ~70 days. In my second aim, I developed a lower-temperature melt-cast biodegradable microneedle patch for sustained release of contraceptive or islatravir (HIV treatment/pre-exposure prophylaxis). Microneedle patches were characterized for their composition, attachment to a water-soluble backing, skin insertion, and in vitro release profile. This study showed that an optimized, moderate-temperature, melt-casting approach with applied centrifugal force resulted in MNPs with successful skin insertion and sustained drug release for 40 days. Guided by findings in my previous aims, my third aim addressed the fabrication of a core-shell microneedle structure through melt casting for extended release of contraceptive for months. The microneedle shell was designed to form a membrane to modulate drug delivery and reduce burst release. The core-shell microneedle patches were characterized for their composition and in vitro release profile. We showed that a melt-based approach resulted in a well-defined core-shell structure microneedle which could be scaled to larger MNs that provided sustained LNG release for 70 days. Overall, this research developed multiple melt-cast microneedle patch designs composed of biodegradable polymer, levonorgestrel, and a removable backing as a long-acting contraceptive method.