Identification of 5-aminosalicylic acid, ciprofloxacin and azithromycin by abrasive stripping voltammetry.

Solid microparticles of 5-aminosalicylic acid, ciprofloxacin, and azithromycin were mechanically immobilized on the surface of the paraffin impregnated graphite electrode and investigated by square-wave and cyclic voltammetry in order to develop a method for their qualitative determination. 5-Aminosalicylic acid is oxidized at 0.540 V in the quasireversible electrode reaction, which is followed by the chemical transformation of the product, while ciprofloxacin and azithromycin are oxidized at 1.2 V and 0.94 V, respectively, in totally irreversible electrode reactions. The detection of these drugs in commercial dosage formulations is reported.