1985 年 105 巻 6 号 p. 580-585
The crystallinity of cyclodextrins has been evaluated by using powder X-ray diffraction techniques. α-Cyclodextrin·6H2O and β-cyclodextrin·12H2O were transformed into dehydrate forms by heating at 110°C for 3 h in vacuo. When the cyclodextrin hydrate or dehydrate was ground by vibrational mill, it converted from crystalline state to amorphous state. Crystallinities of intact and ground cyclodextrins were calculated by Ruland's method. In Ruland's method, as the integral upper limit affects significantly the evaluation of crystallinity, we determined the crystallinity by using continuous regions of the integral upper limit. The crystallinities and disorder parameters were determined as 83.4%, 3.2A2, for α-cyclodextrin·6H2O, 87.6%, 4.3A2, for β-cyclodextrin·12H2O and 51.5%, 4.3A2 for β-cyclodextrin dehydrate, respectively. The crystallinities of these three crystals decreased to about 8% by 3 min grinding.