Triplet photochemistry of suprofen in aqueous environment and in the beta-cyclodextrin inclusion complex.

The photodecarboxylation of suprofen in the carboxylate form was studied in aqueous medium as a function of the temperature, the concentration and the presence of oxygen by steady-state and time-resolved photochemical techniques. The process is characterized by an activation energy of 9-10 kcal/mol, the precursor state being the lowest triplet which is of pi-pi* nature. The reactivity of the drug was also studied in the beta-cyclodextrin inclusion complex and an additional photoreaction involving the macrocycle as reactive species was observed. Representative NMR and circular dichroism measurements were performed. Singlet molecular oxygen formation was also investigated.