Electrochemical characterization of cefadroxil β-lactam antibiotic and Cu(II) complex formation.

The electrochemical behaviour of cefadroxil, a first-generation β-lactam antibiotic, was studied at glassy carbon electrodes in aqueous media over a wide range of pH. The first oxidation process is of the phenol moiety and follows an ECE mechanism, generating catechol and resorcinol derivatives as sub-products, which are then reduced and oxidized in subsequent cycles. The sulphur heteroatom present in the cyclic structure close to the β-lactam moiety is oxidized in two steps generating sulphoxide and sulphone. This process was identified from direct comparison with amoxicillin, which has a similar molecular structure, although they belong to different classes of β-lactam antibiotics. For amoxicillin, oxidation of the sulphur heteroatom occurred at more positive potentials, most likely due to structural difficulties in stabilizing the charged oxidized species. Formation of a complex between copper (II) and each of the antibiotics was studied by cyclic voltammetry. Finally, determination of cefadroxil in commercial samples was successfully carried out. • Electrochemical characterization of cefadroxil at glassy carbon in aqueous media • Oxidation of the phenol moiety by ECE mechanism generating catechol and resorcinol • Comparison between electrochemical profile of cefadroxil and amoxicillin • The phenol oxidation process was used to obtain a limit of detection of 0.3 μM. • Phenol oxidation was used to measure the amount of cefadroxil in commercial samples. [ABSTRACT FROM AUTHOR]