Characterization of Recrystallized Carbamazepine Using Acetone as Solvent

Abstract

Carbamazepine is used as a first line drug in seizure treatment. It is classified as BCS class II according to the Biopharmaceutical classification system which means that carbamazepine has high membrane permeability and low water solubility. This makes dissolution the rate limiting process in carbamazepine absorption. Thus crystallization of carbamazepine using the solvent acetone was chosen to increase dissolution rates and improve the bioavailability of carbamazepine. This study therefore aims to compare the characteristics and dissolution rate of carbamazepine recrystallized with acetone using two methods; rapid cooling and solvent evaporation. Characterization of carbamazepine crystals was carried out using Differential Thermal Analysis (DTA), Fourier Transform Infrared (FTIR) Spectroscopy, X-Ray Diffractometry (XRD) and Scanning Electron Microscopy (SEM) while dissolution test was carried out using Type I Dissolution Apparatus operated at 100 rpm and in 900 mL of CO2-free water medium at a temperature of 37 ± 0.5 ◦C. Sampling was carried out at 5, 10, 15, 20, 30, 45, and 60 minutes. The results showed that the melting point, infrared absorption and crystallinity of the acetone recrystallized carbamazepine did not show significant changes compared with the initial carbamazepine compound. The morphology of the recrystallized carbamazepine crystals using the two methods produced a polycrystalline structure which influenced the rate of dissolution. The dissolution rate of acetone recrystallized carbamazepine significantly increased the dissolution of carbamazepine, with a faster dissolution rate for carbamazepine recrystallized using rapid cooling method than the solvent evaporation method or the initial carbamazepine compound.