An Improvement of Physicomechanical Properties of Carbamazepine Crystals

In order to improve particle properties, new processes combining granulation and crystallization are being developed. This work deals with the spherical crystallization process by the quasi-emulsion mechanism applied to carbamazepine, a pharmaceutical drug. The aim of the present study was to produce of spherical grains made of mall crystals of a drug that have adequate properties for direct compression when manufacturing tablets. Crabamazepine was crystallized under different conditions and the obtained spherical crystals were examined in terms of flow properties, particle size analysis, compression and dissolution behaviors. Physical characteristics of the crystals were studied for the morphology of crystals using scanning electron microscope, for the identification of polymorphism by x-ray powder diffraction and for thermodynamic properties using differential scanning calorimetry. The results showed that the agglomerates produced at 5°C under stirring rate of 300 rpm had superior flow than other agglomerates. Further more the results suggest that agglomerates flow and pack smoothly from the hopper into the die and that tablets formed from agglomerates attain uniformity in weight due to spherical shape of the treated samples. The results showed that, generally, the treated carbamazepine samples (agglomerated forms) possessed superior mechanical and better dissolution rate characteristics to untreated crystals. The results of DSC and x-ray showed that untreated sample and agglomerates were form III and form I of carbamazepine respectively.