Amperometric Monitoring of Dissolution of pH-Responsive EUDRAGIT(R) Polymer Film Coatings

Abstract

Electrochemical sensors are powerful tools for the detection and real-time monitoring of a wide variety of analytes. However, the long-term operation of Faradaic sensors in complex media is challenging due to fouling. The protection of the electrode surface during in vivo operation is a key element for improving the monitoring of analytes. Here, we study different EUDRAGIT(R) controlled release acrylate copolymers for protecting electrode surfaces. The dissolution of these polymers-namely EUDRAGIT(R) L 30 D-55 and EUDRAGIT(R) FS 30 D-is triggered by a change in pH of the environment, and it is electrochemically monitored by detecting electrode access by means of a redox probe. The full dissolution of the polymer is achieved within 30 min and the electrode response indicates a complete recovery of the original electrochemical performance. We demonstrate that amperometric sensing is a practical and straightforward technique for real-time and in situ sensing of EUDRAGIT(R) dissolution profiles. It will find future applications in determining the protection of polymer electrode coating in real matrices and in vivo applications.