Radiation chemistry studies on chemotherapeutic agents. Part 1.—Pulse radiolysis of adrenalin in aqueous solutions

Abstract

Adrenalin has been studied as a model radiation protective agent by means of pulse radiolysis in aqueous solutions. The rate constants for the reactions of adrenalin with e^–_aq and OH were determined : k(e^–_aq+ adr—NH⁺₂)= 7.5 × 10⁸ dm³ mol^–1 s^–1, k(e^–_aq+ adr—NH)= 2.5 × 10⁸ dm³ mol^–1 s^–1, and k(OH + adr)= 2.2 × 10¹⁰ dm³ mol^–1 s^–1(pH = 9.2). e^–_aq attacks the amino group by splitting off methylamine, whereas OH and O^–_aq lead to the formation of the corresponding adducts of the cyclohexadienyl type. OH radicals can also abstract an electron from an O^– group at pH > 8.