Chemical changes following γ-irradiation of benzylpenicillin in aqueous solution

Abstract

The effects of γ-irradiation on aqueous solutions of sodium benzylpenicillin have been investigated. Pulse radiolysis indicates that both hydrated electrons and hydroxyl radicals are responsible for the degradation between 10^–4 and 10^–2M solute concentrations. Reaction of hydroxyl radicals with the benzene ring of the penicillin side-chain leads to the formation of o-, m-, and p-hydroxybenzylpenicillins. Hydroxyl radicals also induce cleavage of the β-lactam ring, yielding benzylpenilloic and benzylpenicilloic acid. Reaction of hydrated electrons with penicillins generally lead to molecular rearrangements yielding products such as benzylpenillic acid.