Electrochemically controlled release of antischistosomiasis agents from polypyrrole

Schistosomiasis is the second most prevalent typical disease in the world, affecting millions of people, the majority being young children. In this paper, two antischistosomiasis compounds, praziquantel (PZQ) and trichlorfon (TCF), have been incorporated into polypyrrole (PPy) on Pt, indium-tin oxide glass and reticulated vitreous carbon (RVC) using electrochemical methods. Films were characterised using electrochemical techniques, SEM, FTIR spectroscopy and X-ray photoelectron spectroscopy (the latter confirming incorporation of TCF). Studies were focused on TCF due to its high water solubility and hence greater promise for use in vivo. Release of TCF from PPy on RVC was followed using GCMS, where release was ca. twice as high at -300 mV vs. SCE compared to open circuit conditions. At -400 mV, 6.43 mmol was released after just 60 min compared to 6.93 mmol released after 24 h at -300 mV. At -500 mV, a reduced amount of TCF (4.72 mu mol) was released after 60 min compared to that at -400 mV (6.43 mu mol). Thus, TCF was successfully incorporated into PPy and its release could be electrochemically controlled. Such films could be used for the construction of delivery devices.