Fluorescence Analysis of The Interaction Between Cefotaxime Sodium and Chloramphenicol as Well as Bovine Serum Albumin

In Tris-HCl buffer medium of pH 7.40,the binding reaction between cefotaxime sodium(CTX) and chloramphenicol(CHL) with bovine serum albumin(BSA) at different temperatures was studied by fluorescence spectroscopy.The results show that the values of binding constants decrease with the increasing temperature,the quenching mechanism of the combination for BSA and drugs is a static procedure.In addition,the competitive experiments suggest that the primary binding site for both CTX and CHL are located at site Ⅰ in sub-domain ⅡA of BSA.The values of Hill's coefficients are approximately equal to 1 in the binary systems,which indicate no cooperativeness in the drug's binding with BSA.The fluorescence would quench to a larger degree when CTX(or CHL) is added to the system of BSA-CHL(or BSA-CTX).Binding constants of one drug with BSA decrease when the other drug is added.Hill's coefficients of the ternary systems are less than 1.It showed that the negative cooperativity is found when CTX and CHL bound to BSA simultaneously.Thermodynamic parameters indicate that the electrostatic interaction playes a major role in the binding of drugs with BSA.