Electrochemically Controlled Drug Release from a Conducting Polymer Hydrogel (PDMAAp/PEDOT) for Local Therapy and Bioelectronics

Abstract

In this study, the release of fluorescein from a photo-crosslinked conducting polymer hydrogel made from a hydrogel precursor poly(dimethylacrylamide-co-4-methacryloyloxy benzophenone (5%)-co-4-styrenesulfonate (2.5%)) (PDMAAp) and the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) is investigated. Fluorescein, here used as a model for a drug, is actively released through application of an electrical trigger signal. The detected quantity is more than six times higher in comparison to that released from a conventional PEDOT/polysterene sulfonate (PSS) system. Release profiles, drug dose, and timing can be tailored by the application of different trigger signals and pretreatments. To demonstrate that the novel drug release system can be used for a drug relevant for local delivery to a neural interface, experiments are furthermore performed with the anti-inflammatory drug dexamethasone (Dex). The conducting polymer hydrogel facilitates the active release of Dex, in comparison to the previously used PEDOT/Dex. It is suggested that PEDOT/PDMAAp is an interesting alternative for conducting polymer based drug release systems, with the potential to offer more volume for storage, yet retaining the excellent electrochemical properties known for PEDOT electrodes.

Keywords: conducting polymer hydrogel; controlled drug delivery; dexamethasone; fluorescein; neural interfaces.