Ligand-macromolecule complexes: affinity index determination by selective nuclear relaxation analysis

Proton NMR selective and non-selective spin-lattice relaxation rate measure ments were used to monitor the strength of the overall complexation behavio ur of a ligand (carbamazepine) toward a macromolecular receptor (albumin). The 'affinity index,' a quantitative parameter related to the strength of t he ligand-macromolecule interaction, was determined from the experimental c ontribution of the bound ligand molar fraction to the observed selective sp in-lattice relaxation rate. The effect of a second ligand (lamotrigine) on the carbamazepine-albumin interaction was also investigated and was found t o have a modulation effect on the carbamazepine-albumin interaction. Copyri ght (C) 2001 John Wiley & Sons, Ltd.