In vitro Analysis of the Interaction between Ketorolac Tromethamine and Bovine Serum Albumin Using Fluorescence Spectroscopy

Abstract

Objectives: To evaluate the in vitro mutual interaction of ketorolac tromethamine with bovine serum albumin (BSA) using fluorescence spectroscopy under different conditions. Materials and Methods: Different concentrations of ketorolac were mixed with 20 µM bovine serum albumin solution at pH 7.4 and stirred for 2 min at 298 K & 308 K temperatures. Finally different ketorolac-BSA complex at the excitation wavelength 280 nm & 293 nm was measured by the fluorescence spectrophotometer. Results: In the experimental work, it was found that ketorolac is responsible for fluorescence quenching of BSA molecule where tryptophan and tyrosine both amino acid participated in the molecular interactions between BSA and ketorolac at excited state. Stern-Volmer equation is used to calculate fluorescence quenching constant. The thermodynamic parameters such as Gibb’s free energy (∆G), enthalpy change (∆H), and entropy change (∆S) at different temperatures were studied by using Van’t Hoff equation. The values of ΔG, ΔH and ΔS at 298K were -33.25 KJ/mol, 17.093 KJ/mol and 168.94 J/mol for ketorolac. The binding process for ketorolac had been found to be spontaneous, exothermic and entropy driven as indicated by thermodynamic analysis and hydrophobic forces playing a major role in the ketorolac-BSA association. Conclusions: The interaction of ketorolac with BSA was successfully explored using a fluorescence spectroscopic technique.