Spectroscopic analyses on interaction of Naphazoline hydrochloride with bovine serum albumin

The fluorescence and ultraviolet spectroscopy were explored to study the interaction between Naphazoline hydrochloride (Naphcon) and bovine serum albumin (BSA) at three different temperatures (292, 301, and 310 K) under imitated physiological conditions. The quenching mechanism of BSA by Naphacon was interpreted using the Stern–Volmer mechanism, and a combined quenching (dynamic and static quenching). The binding constants, binding sites and the corresponding thermodynamic parameters (ΔG, ΔH, and ΔS) of the interaction system were calculated at different temperatures. According to Förster non-radiation energy transfer theory, the binding distance between BSA and Naphcon was found to be 4.71 nm. Synchronous fluorescence spectroscopy showed the conformation of BSA changed in the presence of Naphacon. In addition, the effect of some common metal ions (Mg2+, Ca2+, Ni2+, Cu2+, and Fe2+) on the binding constant between Naphcon and BSA was examined.

The interaction between Naphazoline hydrochloride and bovine serum albumin was studied by fluorescence and ultraviolet spectroscopy. The quenching mechanism, binding constants, thermodynamic parameters, and binding distance were obtained.Figure optionsDownload as PowerPoint slideHighlights
► We explored the interaction of BSA and Naphcon by spectroscopic methods.
► The fluorescence quenching mechanism is combined quenching.
► Hydrogen bonds and van der Waals forces play a key role in stabilizing the complex.
► The binding constants, binding sites and thermodynamic parameters were calculated.
► The Naphacon affects the conformation of BSA.