Carbamazepine Cocrystals by Solvent Evaporation Technique: Formulation and Characterization Studies

Carbamazepine; an antiepileptic drug, exists in various polymorphic forms out of which Form III is extensively studied as a model  form for  cocrystallization. The main focus of the present study was to cocrystallize Carbamazepine form III with Itaconic acid as a coformer by solvent evaporation technique using Acetone (Class III) as the solvent medium for drug and coformer interaction at molecular level. The obtained Carbamazepine cocrystals were evaluated for parameters like Visual morphology, differential scanning calorimetry, infrared spectroscopy, x-ray diffractometry, contact angle, drug content uniformity, flow properties and in vitro drug release testing. A comparison of the cocrystal characteristics was made with a physical mixture of Carbamazepine with itaconic acid inorder to confirm an interaction at a molecular level between the drug and coformer. The obtained carbamazepine cocrystals showed distinct difference in its morphological characteristics as compared to plain drug. Additionally, the cocrystals showed presence of additional peaks in differential scanning calorimetry thermograph as well as bandshifts in the infrared spectrum. The X-Ray diffractogram of cocrystals was found to show a shift towards left thus confirming a change in the crystal lattice. In vitro drug release testing of cocrystals showed an increase in drug release when compared to drug release from physical mixture and plain drug when tested in 1% Sodium lauryl sulphate. Hence Solvent evaporation technique was found to be successful in producing cocrystals of Carbamazepine polymorph III with Itaconic acid as a coformer.