Investigating Drug Interaction with the Conducting Polymer Films using Quartz Crystal Microbalance

Abstract

Conducting polymers have attracted the interest of researchers as appropriate carrier materials and devices for localized drug delivery. An important factor to consider when employing conducting polymers in drug delivery devices/ systems is the affinity of drug molecules to the material surface. This is particularly critical when the polymers are being used as a gating system to control the delivery of drug to target tissues. This paper focuses on investigating the interaction of an anti-epilepsy drug with the surface of organic conducting polymers (OCPs). The para toluene sulfonic acid (pTS) and chondroitin sulphate (CS) were employed to electropolyerized polypyrrole on the surface of QCM-D quartz crystals. Thickness of deposited OCPs film on the surface of QCM sensor and the amount of absorbed/ desorbed drug molecules were calculated by employing Q-soft software. The surface morphology and roughness of these OCPs were investigated by SEM imaging and optical profilometry respectively. Interaction of the anti-epilepsy drug lacosamide (LCM) to the surface of PPy/pTS and PPy/CS has been investigated under non-stimulated and stimulated (reduced and oxidized) states using the quartz crystal microbalance technique. The frequency, energy dissipation, and adsorbed mass changes of OCPs films were measured during the experiment by using QCM-D technique. Results revealed that, under non-stimulated condition, the LCM molecules showed a greater affinity to the surface of PPy/pTS rather than PPy/CS. The surface roughness of PPy/pTS OCP film was 2.1 times higher than PPy/ CS OCP film. At the stimulated state, the frequency, energy dissipation and LCM molecules adsorption/desorption was dependent on changing of OCP films hydrophilicity. In general, drug molecules demonstrated a greater affinity to PPy/CS in comparison with PPy/pTS. Results showed that PPy/pTS OCP film is a proper bio material to fabricate the implantable drug delivery device to release LCM molecules at fully reduced state.