Inclusion complexes of bropirimine with β-cyclodextrin in solution and in solid state

Bropirimine was found to form an inclusion complex with β-Cyclodextrin in aqueous solution and in the solid phase. Phase-solubility and UV spectroscopic studies revealed the formation of a 1:1 complex. The usefulness of the ultrafiltration technique for studying this interaction was proved and the stability constant of the complex was calculated using simple equations. Chemical-shift changes observed in the 1 H-NMR spectra of both the host and guest molecules clearly indicated complex formation and confirmed the penetration of part of bropirimine molecule into the β-Cyclodextrin cavity. The formation of the complex in the solid state was confirmed by differential scanning calorimetry, CP-MAS 13 C-NMR. and infrared spectroscopy.