Polymorphism of carbamazepine: solid-state studies on carbamazepine dihydrate.
Carbamazepine dihydrate (CBZ.2H2O) crystallizes in the orthorhombic system, space group Cmca or C2ca. The unit-cell constants are: a = 19.834(7), b = 4.945(1), c = 28.826(9) A. M = 272.27, V = 2827(2) A3, Z = 8, D = 1.280 g.cm-3. Indexed X-ray powerder diffraction pattern is given. Dehydration process was studied by means of thermogravimetry and differential thermal analysis: the enthalpy of dehydration was found at 51 kJ per H2O mole. Thermal dehydration leads to an (anhydrous) gamma-form of CBZ when processed in dry atmosphere. The presence of water vapour induces the formation of the beta-form of CBZ as well as the grinding of CBZ.2H2O at room temperature.
Dugué
J
J
Laboratoire de Chimie Minérale Structurale, (CNRS U.R.A. 200), Faculté des Sciences Pharmaceutiques et Biologiques, Paris.
Céolin
R
R
Rouland
J C
JC
Lepage
F
F
D002220:Carbamazepine / Q000737:chemistry*; D003460:Crystallization; D014961:X-Ray Diffraction
D002220:Carbamazepine