Efficiency of cephalosporin complexation with aromatic compounds

The cephalosporin antibiotics cephradine, cephalexin, cefaclor and cefadroxil form complexes with β-naphthol and several other naphthalene derivatives. In these clathrate-type complexes, the cephalosporins form the host lattice for the naphthalene derivatives. Complexation with β-naphthol analogues can be employed to withdraw cephalosporins selectively from an aqueous solution. In this process, the most important parameter is the complexation efficiency, which expresses the extent to which the cephalosporins can be withdrawn from a solution. The complexation efficiencies for a series of guest molecules are explained in terms of both the thermodynamics of the complexation reaction and the structural features of the cephalosporin complexes. In this manner, insight is gained into the subtle relationship between the molecular structure of naphthalene derivatives and the stability of their complexes with the antibiotics. It is shown which molecular properties of the guest molecules are the most important ones for an optimal complexation efficiency of cephalosporins.