LAUSR

Studies of water contents of solid -cyclodextrin (-CD) in crystallized and vacuum dried conditions are reported. Water contents were estimated using Karl–Fischer (KF) titration and thermo-gravimetric analysis (TGA) techniques. It was found that the water contents for crystallized and vacuum-dried samples were 6.93 and 0.86 moles of water per -CD molecule respectively. TGA studies gave values of 6.83 and 0.52 moles of water per -CD molecule respectively. The results agree with those reported from X-ray diffraction studies. Also, the molecular weight of the vacuum dried sample was determined using vapour pressure osmometry, which agrees well with the actual molecular weight of -CD. The thermal profiles of -cyclodextrin (-CD) and -CD are presented. The differential scanning calorimetry data was used to calculate specific heat at constant pressure (Cp) at different temperatures (338.15–468.15 K). These results are compared with similar data for CD and discussed in terms of motional contribution to Cp values and related conformational effects.