Reliable NMR experiments for the study of β-cyclodextrin/prostaglandin E2 inclusion complex

Cyclodextrins are natural cyclic oligosaccharides and behave as cage molecules. Since their internal cavity is relatively hydrophobic compared to the highly hydrophilic external face, the cyclodextrins and their derivatives exhibit the capacity to incorporate hydrophobic guests in their internal cavity leading to a wealth of applications. NMR appears as the most efficient approach to investigate and evidence the formation of inclusion complexes in aqueous solution. Dedicated experiments are used to derive thermodynamic properties as well as "molecular model" for the solution structure of inclusion complexes as beta-cyclodextrin/Prostaglandin E-2 complex. Classical "NOESY-type" experiments and especially the ROESY sequence are used to proove interactions in cyclodextrin domain. But, due to intrinsic problems, the basic ROESY sequence can lead to misinterpretations. We investigate in this work alternative 2D 1H-NMR ROESY-type experiments and estimated their relative advantages.