Effects of γ-Irradiation on Sodium Sulphacetamide

The effects of γ-irradiation on sodium sulphacetamide in aqueous solutions and in the solid state have been studied. Pulse radiolysis and steady-state experiments demonstrate that hydrated electrons ( e_ aq⁻) and hydroxyl radicals (OH) are mainly responsible for the degradation between 10⁻⁴-1.2 M solute concentrations. The reaction with e_ aq⁻ yields sulphanilic acid and an additional unidentified product. Hydroxyl radicals give two products which have tentatively been identified as monomeric and dimeric phenolic derivatives of sulphacetamide. Suitable e_ aq⁻ and OH scavengers selectively remove these products. G(-sulphacetamide) is a maximum of 4.8 in aqueous solution and < 0.01 for the solid. The implications of the results in the radiation sterilization of sulphacetamide formulations is discussed.