Evaluation of drug loading capacity and release characteristics of PEDOT/naproxen system: Effect of doping ions

Abstract

Conducting polymers are versatile and robust materials that have recently become attractive as controlled drug delivery systems. Possessing ion exchangeable properties, they can serve as carriers for numerous biologically active species, showing particular applicability in neural tissue engineering and regional chemotherapy. In the pursuit of the design of the most effective controlled drug delivery system, we aimed to compare the performance of the conducting polymer-based matrix as a function of doping anion, using chloride, perchlorate and dodecyl sulfate, respectively, as the primary dopants. Due to their different ion radius and mobility, selected ions were found to provide substantial changes into polymer characteristics, having strong effects into the uptake and release of a model drug, naproxen sodium salt. PEDOT/ClO 4 matrix, particularly, was found to possess superior properties providing highest mass of the formed polymer (103.45 ± 10.09 µg cm -2 ), charge storage capacity (44.9 mC cm -2 ) and ion exchange capacity (0.122 ± 0.003 µmole cm -2 ), leading also to the highest amounts of loaded (0.024 ± 0.002 µmol cm -2 ) and released (from 0.71 ± 0.10 µg cm -2 to 1.61 ± 0.59 µg cm -2 ) drug.

The Synergistic Effects of Gold Particles and Dexamethasone on the Electrochemical and Biological Performance of PEDOT Neural Interfaces

“…SEM imaging (Figure 3A) revealed that PEDOT derived coatings possessed a porous and rough surface structure as previously reported [34]. Conducting electropolymerization in the presence of Dex induced a modest change in morphology and the formation of larger grains were observed [35,36].…”

“…Negatively charged drugs, such as Dex, are typically immobilized during oxidative polymerization of EDOT, and consecutively released during the spontaneous dedoping of the polymer [6]. The kinetics of the release is the function of the physicochemical parameters of the polymer coating, such as its porosity, morphology and ion exchange capacity, as well as the properties of the drug itself, including ion size and mobility, and can be facilitated by an external stimuli, e.g., an electrical potential [34].…”

Nanoparticle Doped PEDOT for Enhanced Electrode Coatings and Drug Delivery

“…The result is a highly controlled release mechanism, which is entirely localized only to the site of implantation. Researchers use conducting polymer‐based drug delivery to release therapeutics, dyes, and neurotransmitters and neuromodulators …”

Electrodeposited poly(3,4-ethylenedioxypyrrole) films as neural interfaces: Cytocompatibility and electrochemical studies

“…It can also be inferred that positively charged PEDOP oligomers are attracted by the negatively charged structural units of PSS, resulting in the stacked arrangement of pyrrole rings, as in a case of PEDOT/PSS[45,46]. Conversely, the surface of PEDOP films doped with smaller ions (chlorides/phosphates and PTS), was composed of polymer grains regularly dispersed over the Pt surface, in a similar way as observed for PEDOT[7,24]. These matrices exhibited also high values of roughness (R a of 96.5 nm and 215 nm for PEDOP/PBS and PEDOP/PTS, respectively), which had the effect on the wettability of the surfaces.…”

“…The doping ion is used to maintain the electroneutrality of the polymer, since the process of polymerization involves the formation of radical cations [23]. Through the choice of dopant, it is possible to tailor such properties as electrical conductivity [24], surface morphology [25] and polymer elasticity [26], considerations for the design of a neural interface technologies. The most well studied dopants for oxidative polymerization include buffer salts and perchlorates, and more recently, aromatic sulfonate compounds, such as p-toluenesulfonate (PTS) and polystyrene sulfonate (PSS) [5].…”