Abstract

The mechanism of interaction of five phenothiazine derivatives with serum albumin was investigated using fluorescence spectroscopy. It was found that phenothiazine ring common to all drugs makes major contribution to interaction. However, the nature of alkyl amino group at position 10 influences the protein binding significantly. Binding affinities could be related to parachor values of drugs. Fluorescence intensity data in the presence of additives showed that hydrophobic Interactions play a significant role. Stern-Volmer plots indicated the presence of a static component in the quenching mechanism. Results also showed that both tryptophan residues of protein are accessible to drug molecules. The high magnitude of the rate constant of quenching Indicated that the process of energy transfer occurs by intermolecular interaction forces and thus drug binding site is in close proximity to tryptophan residues of BSA.