Multi-physics simulations for investigating the effect of electrode conditions on transscleral ocular iontophoresis for particulate drug delivery into ocular tissues

Sangjun Lee; Se-Na Kim; Chany Lee; Young Bin Choy; Chang-Hwan Im

doi:10.1007/s13534-024-00359-2

Multi-physics simulations for investigating the effect of electrode conditions on transscleral ocular iontophoresis for particulate drug delivery into ocular tissues

Biomed Eng Lett. 2024 Feb 12;14(3):439-450. doi: 10.1007/s13534-024-00359-2. eCollection 2024 May.

Authors

Sangjun Lee^{1

2}, Se-Na Kim³, Chany Lee⁴, Young Bin Choy^{3

5

6}, Chang-Hwan Im^{1

2}

Affiliations

¹ Department of Biomedical Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong- gu, Seoul, 133-791 Republic of Korea.
² Department of Electronic Engineering, Hanyang University, Seoul, Republic of Korea.
³ Institute of Medical & Biological Engineering, Medical Research Center, Seoul National University, Seoul, Republic of Korea.
⁴ Department of Structure & Function of Neural Network, Korea Brain Research Institute, Daegu, Republic of Korea.
⁵ Interdisciplinary Program in Bioengineering, College of Engineering, Seoul National University, Seoul, Republic of Korea.
⁶ Department of Biomedical Engineering, Seoul National University College of Medicine, Seoul, Republic of Korea.

PMID: 38645594
PMCID: PMC11026336 (available on 2025-02-12)
DOI: 10.1007/s13534-024-00359-2

Abstract

Purpose: Transscleral ocular iontophoresis has been proposed to deliver charged particulate drugs to ocular tissues effectively by transmitting a weak electrical current through the sclera. The electric fields formed are influenced by the electrode conditions, thus affecting the amount of particulate drugs delivered to the ocular tissues via iontophoresis. Computational simulation is widely used to simulate drug concentrations in the eye; therefore, reflecting the characteristics of the drugs in living tissues to the simulations is important for a more precise estimation of drug concentration. In this study, we investigated the effect of electrode conditions (location and size) on the efficacy of transscleral iontophoresis.

Methods: We first determined the simulation parameters based on the comparison of the amount of drug in the sclera in the simulation and in vivo experimental results. The injection of the negatively charged nanoparticles into the cul-de-sac of the lower eyelid was simulated. The active electrode (cathode) was attached to the skin immediately above the injection site, while the return electrode (anode) was placed over the eyebrow. The drug concentration distribution in the eye, based on either the location or size of each electrode, was evaluated using the finite element method with the estimated simulation parameters.

Results: Our results indicate that drug permeability varies depending on the location and the size of the electrodes.

Conclusion: Our findings demonstrate that the determination of optimal electrode conditions is necessary to enhance the effectiveness of transscleral iontophoresis.

Supplementary information: The online version contains supplementary material available at 10.1007/s13534-024-00359-2.

Keywords: Electrode condition; Finite element method; Nernst–Planck equation; Ocular iontophoresis; Transscleral drug delivery.

© Korean Society of Medical and Biological Engineering 2024. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.