[Study on the interaction of Nimodipine and bovine serum albumin by fluorescence quenching method].

The interaction of Nimodipine and bovine serum albumin (BSA) was studied using fluorescence spectroscopy (FS) and ultraviolet spectroscopy (UV). The apparent binding constants (KA) between Nimodipine and BSA were 5.01 x 10(4) (26 degrees C) and 4.46 x 10(4) (36 degrees C), and the binding sites (n) were 1.08 +/- 0.01. According to the Förster theory of non-radiation energy transfer, the binding distances (r) were also obtained. The experimental results showed that Nimodipine could quench the inner fluorescence of BSA by forming the Nimodipine-BSA complex. It was found that both static quenching and non-radiation energy transfer led to the fluorescence quenching. The process of binding was a spontaneous molecular interaction in which entropy increased while Gibbs free energy decreased. The thermodynamic parameters indicated that the interaction of Nimodipoine and BSA was driven mainly by static electrical force.