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Effect of Surface Interactions on Microsphere Loading in Dissolving Microneedle Patches
Derek Jang1, Jie Tang2, Steven P Schwendeman2
1Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
ACS Applied Materials & Interfaces
|June 22, 2022
Summary
Microneedle (MN) patches can deliver drugs, but hydrophobic microspheres (MSs) adhere to molds. Modifying surface interactions with surfactants significantly improved MS loading and delivery efficiency in MN patches.
Area of Science:
- Materials Science
- Biomedical Engineering
- Pharmaceutics
Background:
- Microneedle (MN) patches offer a minimally invasive method for transdermal drug delivery.
- Drug-loaded microspheres (MSs) are utilized for controlled release applications.
- Fabrication challenges exist in efficiently loading MSs into MN tips.
Purpose of the Study:
- To investigate the loading efficiency of poly(lactic-co-glycolic acid) (PLGA) microspheres (MSs) into microneedle (MN) patches.
- To identify the surface interactions responsible for poor MS localization in MN tips during fabrication.
- To enhance MS loading and delivery efficiency by modulating these surface interactions.
Main Methods:
- Fabrication of PLGA microspheres and their attempted loading into poly(dimethylsiloxane) (PDMS) MN molds using aqueous formulations.
- Surface characterization and analysis of interactions between MSs and PDMS mold surfaces.
- Modification of MS/mold surface properties via surfactant addition and surface treatments.
- Evaluation of MS loading into MN tips and transdermal delivery efficiency using ex vivo porcine skin models.
Main Results:
- PLGA MSs exhibited poor localization in MN tips due to adhesion to the PDMS mold, primarily driven by hydrophobic interactions.
- Polystyrene MSs, despite similar negative charges to PLGA MSs, also showed adhesion attributed to hydrophobic interactions.
- Reducing hydrophobic interactions by adding a surfactant or modifying mold surfaces increased MS loading into MN tips by threefold.
- Transdermal delivery efficiency into porcine skin ex vivo also increased by threefold following these modifications.
Conclusions:
- Surface interactions, particularly hydrophobic ones, significantly impede the loading of hydrophobic MSs into MN patches during aqueous fabrication.
- Modulating these surface interactions, for instance, by incorporating surfactants, can substantially enhance MS loading and subsequent transdermal delivery efficiency.
- This study provides a strategy to improve the fabrication and performance of drug-loaded MN patches for enhanced drug delivery.
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