High-field nuclear magnetic resonance techniques for the investigation of a beta-cyclodextrin:indomethacin inclusion complex.
The inclusion complex of indomethacin sodium salt in beta-cyclodextrin has been studied by proton NMR at high magnetic field. The continuous variation technique was used to evidence the formation of a soluble 1:1 complex in aqueous solution at physiological pH. The effective association constant was determined by the Benesi-Hildebrand procedure to be 760 M-1 at 303 K. This technique requires NMR measurements in the presence of a very large excess of one of the complex components and, since both beta-cyclodextrin and the sodium salt of indomethacin are sparingly soluble in water, NMR spectrometers operating at very high magnetic fields were used. Besides the effective association constant, the Benesi-Hildebrand approach allows a precise determination of all NMR parameters of the pure inclusion complex which may be used for a complete analysis of the geometry of this complex in solution.
Djedaïni
F
F
DLPC/SCM, Centre d'Etudes, Nucléaires de Saclay, Gif/Yvette Cedex, France.
Lin
S Z
SZ
Perly
B
B
Wouessidjewe
D
D
D003505:Cyclodextrins / Q000032:analysis*; D003912:Dextrins / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D007213:Indomethacin / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy; D013213:Starch / Q000032:analysis*; D047392:beta-Cyclodextrins
D003505:Cyclodextrins; D003912:Dextrins; D047392:beta-Cyclodextrins; D013213:Starch; C031215:betadex; D007213:Indomethacin