Effect of Surface Interactions on Microsphere Loading in Dissolving Microneedle Patches

• Type of Material: Article
• Authors: Derek Jang, Emory University; Jie Tang, University of Michigan; Steven P Schwendeman, University of Michigan; Mark Prausnitz, Emory University
• Language: English
• Date: 2022-06-22
• Publisher: AMER CHEMICAL SOC
• Publication Version: Final Published Version
• Copyright Statement: © 2022 The Authors. Published by American Chemical Society
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1021/acsami.2c05795
• Title of Journal or Parent Work: ACS APPLIED MATERIALS & INTERFACES
• Volume: 14
• Issue: 26
• Start Page: 29577
• End Page: 29587
• Keywords: drug delivery; CONTROLLED-RELEASE; surface interactions; microneedle patch; SUSTAINED-RELEASE; hydrophobicity; Technology; Nanoscience & Nanotechnology; Science & Technology - Other Topics; ENCAPSULATION; POLYMER MICRONEEDLES; Materials Science; ARRAYS; Science & Technology; SYSTEMS; Materials Science, Multidisciplinary; electrostatic repulsion; DRUG-DELIVERY; microsphere loading
• Research Categories: Engineering, Biomedical

Abstract

Microneedle (MN) patches enable simple self-administration of drugs via the skin. In this study, we sought to deliver drug-loaded microspheres (MSs) using MN patches and found that the poly(lactic-co-glycolic acid) (PLGA) MSs failed to localize in the MN tips during fabrication, thereby decreasing their delivered dose and delivery efficiency into skin. We determined that surface interactions between the hydrophobic MSs and the poly(dimethylsiloxane) (PDMS) mold caused MSs to adhere to the mold surface during casting in aqueous formulations, with hydrophobic interactions largely responsible for adhesion. Further studies with polystyrene MSs that similarly carry a negative charge like the PLGA MSs demonstrated both repulsive electrostatic interactions as well as adhesive hydrophobic interactions. Reducing hydrophobic interactions by addition of a surfactant or modifying mold surface properties increased MS loading into MN tips and delivery into porcine skin ex vivo by 3-fold. We conclude that surface interactions affect the loading of hydrophobic MSs into MN patches during aqueous fabrication procedures and that their modulation with the surfactant can increase loading and delivery efficiency.