Ultrafast fluorescence dynamics in flurbiprofen-amino acid dyads and in the supramolecular drug/protein complex

Abstract

The interaction dynamics between the drug flurbiprofen (FBP) and human serum albumin (HSA) has been investigated by time-resolved fluorescence spectroscopy, combining femtosecond fluorescence upconversion and picosecond time-correlated single photon counting. In order to obtain additional information on the drug/protein interaction, several covalently linked model dyads, composed of FBP and tryptophan or tyrosine, were also studied. For all systems, the main feature was a remarkable dynamic FBP fluorescence quenching, more prominent in the dyads than in the protein complex. All systems also displayed a clear stereoselectivity depending on the (S)-or (R)-form of FBP, that was strongly influenced by the conformational arrangement of the investigated chromophores.