STUDIES ON ELECTROCHEMICAL-BEHAVIOR OF CEPHALEXIN

Cephalexin, which contains an unsubstituted 3-methyl group, but no reducible group, does not give a reduction peak at a dropping mercury electrode, whereas its degradation product does. The degradation of cephalexin was carried out in 0.1 M NaOH at 100-degrees-C for 20 min. A sensitive reduction peak of cephalexin was obtained by adsorptive stripping voltammetry in 0.1 M NaOH at an accumulation time of 60 s. The peak potential is - 0.80 V (vs. Ag/AgCl). The peak current is directly proportional to the concentration of cephalexin, with a detection limit of 5.0 x 10(-10) M. The electrochemical behaviour of cephalexin was studied. The reduction process is quasi-reversible with adsorptive characteristics. The mechanisms of degradation and electrode reaction are discussed.