Complex formation of native and hydroxypropylated cyclodextrins with benzoic acid in aqueous solution: Volumetric and 1H NMR study

► Novel data on benzoic acid binding with CDs were obtained by densimetry and 1H NMR. ► Negative volume changes are observed for α-CD and γ-CD binding. ► Positive volume changes are due to considerable dehydration of β-CD cavity. ► Hydroxypropyl substituents favors binding of benzoic acid with β-CD and γ-CD.