In this paper, the polypyrrole (PPy) film modified electrodes are used
as an electroreleasing reservoir. The electrochemically controlled re
lease of 5-fluorouracil (5-FU) from a PPy film modified electrode to a
queous electrolytes is studied by the in situ probe beam deflection (P
BD) method combined with cyclic voltammetry (CV) and chronoamperometry
(CA). The PBD results reveal that the release of 5-FU from PPy film d
epends on the electrochemical redox process of the PPy film electrode.
The released amount is controlled by the reduction potential and is p
roportional to the thickness of the film. The exchange of 5-FU anions
with Cl- on an open circuit is slow on the time scale of minutes, but
the release of 5-FU anions can proceed quickly at -0.6 V (vs Ag/AgCl).
The amount of released 5-FU decreases with the time that the PPy film
is soaked in aqueous solution. (C) 1998 Elsevier Science Ltd. All rig
hts reserved.