Chemical speciation and molecular modelling studies on interaction of cephalothin with metal ions

Abstract

Chemical speciation and molecular modelling studies have been carried out for accessing the interaction of metal ions with cephalothin and distribution of metal cephalothin species in biological fluids. Chemical speciation has been carried out using the program BEST and SPE and the method of Bjerrum and Calvin, as modified by Irving and Rossotti has been used to find out the values of stability constants. The order of stability constants for metal complexes is found to be: Mg(II) < Mn(II) < Co(II) < Cd(II) < Zn(II) < Ni(II) < Cu(II) Molecular modelling studies have been carried out by using HyperChem Suite release 5.1 Professional Version for molecular modelling studies. It is found that Zn(II) binds to cephalothin through the nitrogen of dihydrothiazine ring and carboxylate group at C-4.