New Methods for Preparing Cyclodextrin Inclusion Compounds. IV. Enhancement of Combining Molar Ratio by Using a Ground Mixture in Heptakis-(2,6-di-O-methyl)-β-cyclodexitrin and Benzoic Acid System

The inclusion compound of heptakis-(2,6-di-O-methyl)-β-cyclodextrin (DMβCD) with benzoic acid was prepared by heating the ground mixture in a sealed container. The formation of teh inclusion compound was investigated quantitatively as a functions of heating temperature, heating time, and grinding time. Differential scanning calorimetry (DSC) measurements were made of the ground mixture at different grinding times. From teh DSC measurements, it was found that the temperature of crystallization of an amorphous ground mixture increased with an increase in grinding time. When the ground mixture was heated in a sealed container, the combining molar ratio of benzoic acid to DMβCD increased as the heating temperature increased. The experimental results indicated that the inclusion compound was obtained more effectively by heating the ground mixture rather than by heating the physical mixture.