Characterization and molecular modeling of the inclusion complexes of 2-(2-nitrovinyl) furan (G-0) with cyclodextrines.

The objective of this study was to prepare and characterize complexes of 2-(2-nitrovinyl) furan (G-0) with 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) and sulfobutyl ether-β-cyclodextrin (SBE-β-CD). The solid inclusion complexes were prepared using kneading and freeze-drying methods. Phase solubility profiles were used to obtain the apparent stability constants and the complexation efficiency. They were classified as A(L) type for both systems: the apparent stability constants K(1:1) of the complexes were 48.7 and 79.2 M(-1) for HP-β-CD and SBE-β-CD respectively. The solid inclusion complexes were evaluated by means of differential scanning calorimetry (DSC), X-ray diffraction (XRD) and nuclear magnetic resonance spectroscopy (NMR). Especially the use of the two-dimensional ROESY spectrum was useful to confirm the presence of an inclusion complex. The spatial configuration of the drug inside the cyclodextrin cavity was investigated using molecular modeling studies. The latter results were in agreement with the experimental data. Inclusion complexes of G-0 with HP-β-CD contributed to improve the chemical stability of the drug in the presence of other commonly used pharmaceutical excipients.