Electrochemistry of podophyllotoxin derivatives: Part I. Oxidation mechanism of etoposide (VP 16–213)

Abstract The electrochemical oxidation of the antineoplastic agent etoposide in aqueous solution at a glassy carbon electrode shows an overall two electron transfer. At pH 1 ) is a reversible 1 e − transfer resulting in a stable radical. The second step (peak i 11 ) corresponds to the transfer of the second electron. The product formed after 2 e − oxidation is an unstable cation which undergoes rapid conversion into the orthoquinone. The orthoquinone has been isolated and characterized.