Abstract

The binding of nimesulide, a cox-2 inhibitor, to bovine serum albumin was investigated by equilibrium dialysis method at different temperatures and pH conditions. The Scatchard plots were prepared based on these drug-protein binding data. The number of binding sites (n), the value of association constant (K) at different conditions and different thermodynamic parameters (i.e., standard free energy change ΔG°, standard enthalpy change ΔH° and standard entropy change ΔS°) of nimesulide-BSA binding were determined. The result shows that number of binding sites is around 2.5 and the value of association constant is decreasing with increasing temperature and pH. It also reveals that the value of ΔG° and ΔH° were highly negative and ΔS° was also negative. The result indicates that the interaction between nimesulide and bovine serum albumin is exothermic and spontaneous in nature. It is postulated that nimesulide-bovine serum albumin interaction may occur due to hydrogen bond formation and ionic interaction.