title: Electrochemical characteristics of nitroheterocyclic compounds of biological interest. VI. The misonidazole radical anion.
abstract: The addition of four aprotic solvents to misonidazole in an aqueous buffer system has been examined electrochemically. Qualitatively they all result in separation of the initial irreversible 4 electron reduction step into two stages, the RNO2/RNO2- and RNO2-/RNHOH couples respectively. Despite some difficulties in achieving measurements for the discrete RNO2/RNO2- without interference from the following reduction step, it was clear that the various aprotic solvents influenced the lifetime of the RNO2- species to different degrees. Resolution of the two processes was best achieved using a water-acetone system and this has been employed to study the lifetimes of the misonidazole radical anion as a function of acetone content and drug concentration. Analysis of the cyclic voltammetric response showed a second order decay pathway, in line with the metronidazole system studied under similar conditions. This has been compared with results from pulse radiolysis work, which suggested a first order reaction of unknown pathway for 2-nitroimidazole radical anions.
authors.affiliation: Chemotherapy Research Unit, Polytechnic of East London.
authors.forename: J H
authors.initials: JH
authors.lastname: Tocher
authors.forename: D I
authors.initials: DI
authors.lastname: Edwards
mesh_terms: D000838:Anions; D005609:Free Radicals; D007700:Kinetics; D008920:Misonidazole; D010084:Oxidation-Reduction; D012997:Solvents
chemical_list: D000838:Anions; D005609:Free Radicals; D012997:Solvents; D008920:Misonidazole