Cyclodextrin Inclusion Complex of Racecadotril: Effect of Drug-β- Cyclodextrin Ratio and the Method of Complexation
Mona Semalty, Mitali Panchpuri, Devendra Singh and Ajay Semalty
Affiliation: Department of Pharmaceutical Sciences, H. N. B. Garhwal University, Srinagar (Garhwal) 246 174, Uttarakhand, India.
Racecadotril is an antisecretory and antidiarrheal agent against watery diarrhoea in children. Racecadotril is a
class II drug (as per Biopharmaceutical Classification System) with poor aqueous solubility and dissolution rate limited
absorption. β-cyclodextrin complexation of solubility or dissolution rate limited drugs provides an amphiphilic complex
with improved solubility and dissolution profile. Thus Racecadotril – β-cyclodextrin complex were prepared to improve
its solubility and dissolution by imparting an environment of improved hydrophilicity.
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
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.
Keywords: BCD complex, in vitro dissolution, Racecadotril, solubility.
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