CHARACTERIZATION OF THE TRANSIENT INTERMEDIATES GENERATED FROM THE PHOTOEXCITATION OF NABUMETONE - A COMPARISON WITH NAPROXEN

The photochemical and photophysical properties of nabumetone (4-[6-met hoxy-2-naphthyl]-2-butanone) were examined employing conventional and time-resolved spectroscopic techniques. The naphthalene-like nabumeton e triplet is formed with 29% efficiency in acetonitrile, Singlet oxyge n formation was also detected in this solvent with Phi(Delta) value of 0.19. A naphthalene-like radical cation absorption, formed via biphot onic processes, was also detected. The reactivity of both the triplet and radical cation of nabumetone toward different substrates was exami ned. The photochemical properties of nabumetone are compared with thos e of naproxen, a structurally related acidic nonsteroidal anti-inflamm atory drug. For these two anti-inflammatory agents, a type II photosen sitization process is most likely responsible for their phototoxicity.