Dissolution behavior of β-cyclodextrin molecular inclusion complexes of aceclofenac

The objective of the present investigation was to study the effect of β-cyclodextrin (β-CD) on the in vitro dissolution of aceclofenac (AF) from molecular inclusion complexes. Aceclofenac molecular inclusion complexes in 1:1 and 1:2 M ratio were prepared using a kneading method. The in vitro dissolution of pure drug, physical mixtures, and cyclodextrin inclusion complexes was carried out. Molecular inclusion complexes of AF with β-CD showed a considerable increase in the dissolution rate in comparison with the physical mixture and pure drug in 0.1 N HCl, pH 1.2, and phosphate buffer, pH 7.4. Inclusion complexes with a 1:2 M ratio showed the maximum dissolution rate in comparison to other ratios. Fourier transform infrared spectroscopy and differential scanning calorimetry studies indicated no interaction between AF and β-CD in complexes in solid state. Molecular modeling results indicated the relative energetic stability of the β-CD dimer-AF complex as compared to β-CD monomer-AF. Dissolution enhancement was attributed to the formation of water soluble inclusion complexes with β-CD. The in vitro release from all the formulations was best described by first-order kinetics (R(2) = 0.9826 and 0.9938 in 0.1 N HCl and phosphate buffer, respectively) followed by the Higuchi release model (R(2) = 0.9542 and 0.9686 in 0.1 N HCl and phosphate buffer, respectively). In conclusion, the dissolution of AF can be enhanced by the use of a hydrophilic carrier like β-CD.