Correlation of cyclic voltammetry behaviour and photooxidative properties of indoprofen and its photoproducts

The electrochemical behaviour of indoprofen (INP) and its photoproducts was investigated in acetonitrile containing tetrabutylammonium hexafluorophosphate at a Pt or Cv ultramicro-electrodes. These photosensitizers (PS) undergo irreversible oxidation yielding at first a radical cation PS+ and more or less reversible reductions through monoelectronic exchange involving a radical anion PS−. 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−. Cyclic voltammetry was found powerful in order to get a new insight in the photosensitizing properties of drugs.