The electrochemical behaviour of indoprofen (INP) and its photoproducts was investigated in acetonitrile containing tetrabutylammonium hexalluorophosphate at a Pt or Cv ultramicro-electrodes. These photosensitizers (PS) undergo irreversible oxidation yielding at first a radical cation PS center dot+ and more or less reversible reductions through monoelectronic exchange involving a radical anion PS center dot-. By varying the potential scan speed, the stabilities of the radical anions were evaluated. The determination of the redox potential and Rehm-Weller's equation shows the high exergonicity of the oxidative photodamagings whatever is the compound PS. The difference in DNA photosensitizing properties could rather be related to a kinetic control and then to the relative stabilities of the radical anions PS center dot-. Cyclic voltammetry was found powerful in order to get a new insight in the photosensitizing properties of drugs. (c) 2006 Elsevier Ltd. All rights reserved.