title: Redox reactions of sanazole (AK-2123) in aqueous solutions: a pulse radiolysis study.
abstract: The redox chemistry of sanazole, an efficient hypoxic cell radiosensitizer, generally referred to as AK-2123, was studied by pulse radiolysis with eaq-, CO2-., 2-propanol radicals and CH2OH radicals. AK-2123 reacts with eaq-, CO2-. and 2-propanol radicals at almost diffusion-controlled rates, producing a nitro radical anion (lambda max = 290 nm) within a few microseconds. The decay kinetics of the radical anion was independent of the pH. The radical anion reacts with oxygen with a rate constant of 3.4 x 10(6) dm3 mol-1 s-1. An electron-transfer reaction was observed from the thymine radical anion to AK-2123. From redox equilibria with methyl viologen, the one-electron reduction potential of AK-2123 in aqueous solution, determined by pulse radiolysis, was estimated to be -0.33 +/- 0.02 V vs. NHE. Depletion of intracellular nonprotein thiols did not mitigate the radiosensitizing affect of the hypoxic radiosensitizer, AK-2123.
authors.affiliation: Radiation Chemistry & Chemical Dynamics Division, Nanavati Hospital, Vile Parle, Mumbai 400 056, India. sudhirk@apsara.barc.ernet.in
authors.forename: S
authors.initials: S
authors.lastname: Kapoor
authors.forename: R
authors.initials: R
authors.lastname: Mathew
authors.forename: N G
authors.initials: NG
authors.lastname: Huilgol
authors.forename: T V
authors.initials: TV
authors.lastname: Kagiya
authors.forename: C K
authors.initials: CK
authors.lastname: Nair
mesh_terms: D004579:Electron Transport; D004926:Escherichia coli; D010084:Oxidation-Reduction; D011675:Pulse Radiolysis; D011838:Radiation-Sensitizing Agents / Q000737:chemistry*; D012996:Solutions; D014230:Triazoles / Q000737:chemistry*
chemical_list: D011838:Radiation-Sensitizing Agents; D012996:Solutions; D014230:Triazoles; C072690:AK 2123