Sulfobutyl Ether7 β-Cyclodextrin (SBE7 β-CD) Carbamazepine Complex: Preparation, Characterization, Molecular Modeling, and Evaluation of In Vivo Anti-epileptic Activity

The objective of the present investigation was to study the ability of sulfobutyl ether(7)-beta-cyclodextrin to form an inclusion complex with carbamazepine, an anti-epileptic drug with poor water solubility. The formation of the complex was carried out using the industrially feasible spray-drying method. The inclusion complex and physical mixtures were characterized by various techniques such as differential scanning calorimetry (DSC), infrared (IR), nuclear magnetic resonance (NMR), X-ray diffraction (XRD), and molecular modeling. The DSC, IR, and NMR studies confirmed the formation of an inclusion complex between carbamazepine and sulfobutyl ether(7) beta-cyclodextrin whereas XRD studies indicated an amorphous nature of the inclusion complex. Molecular modeling studies disclosed different modes of interaction between carbamazepine and sulfobutyl ether(7) beta-cyclodextrin with good correlation with experimental observations. The inclusion complex exhibited significantly higher in vitro dissolution profile as compared with pure carbamazepine powder. The in vivo anti-epileptic activity of carbamazepine/sulfobutyl ether(7) beta-cyclodextrin complex was evaluated in pentylenetetrazole-induced convulsions model. The carbamazepine/sulfobutyl ether(7) beta-cyclodextrin complex showed significantly higher anti-epileptic activity (p < 0.01) as compared with that of carbamazepine suspension on oral administration.