Studies on a novel modified β-cyclodextrin inclusion complex

A novel host–guest inclusion complex MAH-β-CD–APAP (MAH-β-CD = a modified β-cyclodextrin carrying seven vinyl carboxylic acid groups; APAP = 4-Acetamino phenol) was prepared. Its structure was characterized by 1H NMR, 13C NMR, IR spectra, thermogravimetric analysis (TGA) and elementary analysis. The results showed that APAP was encapsulated within the MAH-β-CD cavity. Moreover, the important phase solubility studies were carried out, which demonstrated a water-soluble inclusion complex was formed. From the phase-solubility diagram, the stoichiometry and the apparent stability constant (K1:1) were obtained to be 1:1 and 1.43 × 103 L/mol, respectively.