The thermal behaviour of binary mixtures between β-cyclodextrin (β-CD) and either carbamazepine polymorphic Form I (CBZ I),
Form III (CBZ III) or dihydrate was investigated in order to assess possible interactions of CBZ solid phases with β-CD. Physical
mixtures and kneaded binaries of β-CD and different CBZ crystal forms were studied by differential scanning calorimetry, thermogravimetric
analysis and hot stage microscopy. The pattern of transition of CBZ Form III into Form I is strongly influenced by β-CD. The
liquid-solid transition is practically absent when anhydrous CBZ/β-CD mixes are tested, as a consequence of an interaction
between β-CD and liquid CBZ that hinders CBZ recrystallisation as Form I occurring after CBZ Form III melting.
Water loss on heating of CBZ dihydrate in the presence of β-CD leads in all cases to the formation of CBZ Form I.