In the present work, the spectroscopic and kinetic features of the radical species induced in gamma-irradiated sulfacetamide-sodium (SS) was studied at room and at different temperatures in the dose range of 5-50 kGy by electron spin resonance (ESR) technique with the aim of investigating the possibility of radiosterilization and dosimetric features of SS. A model consisting of four radical species of different spectroscopic features denoted as I-IV was found to describe best whole experimental data derived throughout the present work. These species were quite stable at room temperature but relatively unstable above room temperature. Heights of the characteristic resonance peaks measured with respect to the base line were considered to monitor microwave, temperature, time dependent and kinetic features of the radical species contributing to ESR spectrum. Collected experimental data were used to characterize the radical species responsible from ESR spectra through simulation calculations. Possible changes in the IR bands of gamma irradiated SS was also investigated by Fr-IR technique, but no definite difference was observed between unirradiated and irradiated IR spectra of SS. As in other sulfonamides, radiation yield of solid SS was found to be very low (G < 0.1), therefore basing on this result it was concluded that SS and SS containing drugs could, safely, be sterilized by radiation and that SS did not exhibit good dosimetric features. (C) 2004 Elsevier B.V. All rights reserved.