Solid Dispersions - An Approach to Enhance the Dissolution Rate

Oxcarbazepine, 10, 11-dihydro- 10-oxo- 5H-dibenz(b, f)azepine- 5-carboxamide, is an anticonvulsant and mood stabilizing drug, used primarily in the treatment of epilepsy. It is also used to treat anxiety and mood disorders, and benign motor tics. Oxcarbazepine is marketed as Trileptal by Novartis and available in some countries as a generic drug. It is a prodrug which is activated to eslicarbazepine in the liver. It is a white or yellowish-white, crystalline powder; almost odourless, with a molecular weight of 252.268 g/mol. Oxcarbazepine is slightly soluble in acetone, chloroform, dichloromethane, and methanol. It is practically insoluble in ethanol, ether, and water. The drug exhibits low bioavailability related to its poor water solubility. Oxcarbazepine is a class II compound, i.e., water-insoluble, lipophilic, and highly permeable according to Biopharmaceutical Classification System. The purpose of this study was to prepare and characterize solid dispersions of the poor water soluble anticonvulsant with water soluble carrier such as primogel to improve its dissolution properties. The solid dispersions were prepared by co-grinding and solvent evaporation method.