title: Electrochemical behavior of the antifungal agents itraconazole, posaconazole and ketoconazole at a glassy carbon electrode.
abstract: The electrochemical behavior of the azole antifungal agents itraconazole, posaconazole and ketoconazole has been investigated at a glassy carbon working electrode using cyclic voltammetry. All measurements were carried out in a supporting electrolyte solution consisting of a 1:1 (v/v) mixture of 0.1 mol L(-1) sodium phosphate buffers and acetonitrile at various substance concentrations and pH values. An amperometric cell with a three electrode system consisting of a working electrode, a palladium reference electrode and a platinum disk as the auxiliary electrode was used in all experiments. All azoles showed a similar electrochemical behavior involving two reactions. An irreversible oxidation occurred at potentials of about 0.5V. A reduction peak was detected at potentials between -0.28V and -0.14V with an associated oxidation peak, which was observed in consecutive repeated measurements at potentials between -0.03 and 0.28 V. The reduction and corresponding oxidation can be regarded as a quasi-reversible process. The proposed reaction mechanisms are an irreversible oxidation of the piperazine moiety at higher potentials as well as a reduction at lower potentials of the carbonyl group of the triazolone moiety in the case of itraconazole and posaconazole or a reduction of the methoxy group of ketoconazole.
authors.forename: H
authors.initials: H
authors.lastname: Knoth
authors.forename: G K E
authors.initials: GK
authors.lastname: Scriba
authors.forename: B
authors.initials: B
authors.lastname: Buettner
mesh_terms: D000935:Antifungal Agents / Q000737:chemistry*; D002244:Carbon; D055664:Electrochemical Techniques; D004563:Electrochemistry; D004566:Electrodes; D007202:Indicators and Reagents; D017964:Itraconazole / Q000737:chemistry*; D007654:Ketoconazole / Q000737:chemistry*; D012996:Solutions; D014230:Triazoles / Q000737:chemistry*
chemical_list: D000935:Antifungal Agents; D007202:Indicators and Reagents; D012996:Solutions; D014230:Triazoles; D017964:Itraconazole; C101425:posaconazole; D002244:Carbon; D007654:Ketoconazole