Racecadotril was complexed with β-cyclodextrin (in 1:1 and 1:2 molar ratios) by two different methods (solvent evaporation and kneading method). These inclusion complexes were evaluated for solubility, drug content, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X ray powder diffraction (XRPD) and in vitro dissolution study.
The highest drug content (30.83%) was found in complex made by kneading method (RK1:1) in 1:1 molar ratio. Complex prepared by solvent evaporation method (RSE1:1, RSE1:2) were found to be showing irregular disc shaped non-porous surface, while the complexes prepared by kneading method (RK1:1, RK1:2) showed rough, fluffy, non-porous and irregular surface in SEM. Solubility of the drug improved up to 2 to 3 folds in the complexes. The complex RK1:1 showed the greatest improvement in solubility (from 28.98 to76.56 µg/ml). The dissolution of the complexes was also found to be improved. Complex prepared by solvent evaporation method in 1:1 molar ratio (RSE1:1) showed a marked improvement in percent drug release (100.33%) than that of pure drug (52.58%) at the end of 1 hour in dissolution study. FTIR, DSC and XRPD data confirmed the formation of inclusion complex. It was concluded that water solubility of all the complexes were increased when the drug was complexed with β-CD in 1:1 molar ratio. The complex made in 1:1 molar ratio (irrespective of the method) showed better solubility and the dissolution profile as compared to the complex made in 1:2 molar ratio. It was concluded that the complex prepared by the solvent evaporation method showed better solubility and the dissolution due to better amorphization of the drug.