Pulse radiolysis studies of etoposide and 4′-demethylepipodophyllotoxin in aqueous solution

The reactions of etoposide (VP 16, 4'-demethyl-epipodophyllotoxin ethylidene-beta-D-glucoside) and 4'-demethylepipodophyllotoxin (DMEP) with the primary radiolytic products of water, such as e(aq)(-), H-. and (OH)-O-./O.- radicals, and the secondary radical (SO4.-) in aqueous solution were studied by use of the techniques of pulse radiolysis, respectively. The absorption spectra of reaction products with e(aq)(-), H-. and (OH)-O-./O.- and SO4.- radicals were observed, and the rate constants of them were determined by following the build-up kinetics of produced or the decay of hydrated electron observed at 600 nm, respectively. (C) 2000 Elsevier Science. All rights reserved.