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Polymorphic Phase Transitions in Carbamazepine and 10,11-Dihydrocarbamazepine.

ABSTRACT: Temperature-induced phase transitions in carbamazepine (CBZ) and 10,11-dihydrocarbamazepine (DHC) were studied by simultaneous differential scanning calorimetry-X-ray diffraction in this work. The transitions generally involve a transitional melt phase which is quickly followed by recrystallisation. The expansions of the unit cell as a function of temperature could be quantified and allow us to determine a directional order of stability in relation to the lattice constants. Dihydrocarbamazepine form?II undergoes a conversion to form?I by a localised melt phase. Carbamazepine (CBZ) form?IV converts to form?I at 182?°C, again by a localised intermediate melt phase. CBZ form?II converted to form?I at 119?°C by a pathway that appears to have included some melting, and form?III underwent a part melt-recrystallisation and a part sublimation-recrystallisation to form?I.

SUBMITTER: Clout AE

PROVIDER: S-EPMC6175174 | biostudies-literature | 2018 Sep

REPOSITORIES: biostudies-literature

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Polymorphic Phase Transitions in Carbamazepine and 10,11-Dihydrocarbamazepine.

Clout Alexander E AE Buanz Asma B M ABM Gaisford Simon S Williams Gareth R GR

Chemistry (Weinheim an der Bergstrasse, Germany) 20180820 51

Temperature-induced phase transitions in carbamazepine (CBZ) and 10,11-dihydrocarbamazepine (DHC) were studied by simultaneous differential scanning calorimetry-X-ray diffraction in this work. The transitions generally involve a transitional melt phase which is quickly followed by recrystallisation. The expansions of the unit cell as a function of temperature could be quantified and allow us to determine a directional order of stability in relation to the lattice constants. Dihydrocarbamazepine ...[more]

PMID: 29979477

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