Thermal And Structural Characterization of Commercial α-, β-, and γ-Cyclodextrins

α-, β-, and γ-cyclodextrins (CDs) marketed by five different companies were characterized from the thermal and structural point of view. Three αCD samples showed two-step DSC dehydration profiles and their XRD patterns were characteristic for αCD⋅6H₂O form I, whereas one brand with an apparent three-step DSC dehydration behaviour was a mixture of αCD⋅6H₂O form I and anhydrous αCD. The differences in the DSC profiles after dehydration and EGA onset decomposition temperatures recorded for the five βCD brands were attributed to different manufacturing and purification processes. The five γCDs brands showed a common thermal behaviour and very similar XRD patterns. The patterns did not match the idealized pattern of γCD⋅14.1H₂O, indicating the occurrence of two different hydrated crystal structures. This revised version was published online in August 2006 with corrections to the Cover Date.