Carbamazepine spherical agglomerate crystals part I. preparation and evaluation

ABSTRACT

In this study, the spherical agglomeration crystallization method was used to improve the dissolution properties of carbamazepine [CBZ]. Crystal forms 1, 2 and 3 were the agglomerates prepared by using 1, 2.8 and 5 ml of the bridging agent [chloroform], respectively, and stirred for 2 hours. The prepared CBZ crystals were evaluated by microscopic examination, particle size determination, melting point, differential scanning calorimetry [DSC], infrared spectroscopy [IR], X-ray diffraction, equilibrium solubility, dissolution study and stability study for one year. It was evident that raw CBZ belongs to modification III [CBZ [M] or beta form], whereas CBZ spherical agglomerates belongs to modification I [CBZ [T] or alpha-form]. The best results in the crystallization procedures were obtained by the use of 1 ml chloroform [bridging agent], stirring the slurry for 2 hours as well as drying in an oven at 50C for 2 days. Crystal form 1 possessed a higher solubility and a significantly higher dissolution rate compared with raw CBZ and the other crystal forms. In addition, crystal 1 possessed a high stability due to the high degree of crystalline order