DICLOFENAC-BETA-CYCLODEXTRIN INCLUSION IN SOLUTION PROTON MAGNETIC-RESONANCE AND MOLECULAR MODELING STUDIES

The nature of the inclusion complex of the NSAID [2-[(2,6-dichlorophen yl) amino]phenyl]acetic acid (diclofenac) with beta-cyclodextrin and 2 -hydroxypropyl-beta-cyclodextrin was studied by selected 1D and 2D NMR experiments and by molecular modelling studies using Hyperchem(R) sof tware. The results indicate that simultaneous inclusion of both rings occurs even at low drug/CD ratios giving rise to multiple equilibria i n solution (two isomeric 1:1 complexes and a 1:2 complex). Continuous variation plots are supportive of 1:1 stoichiometry indicating that is omeric 1:1 complexes predominate in the range of concentrations studie d.