Enhancement of Dissolution Rate and Physicochemical Characterization of Irbesartan Inclusion Complexes using Cyclodextrins

The purpose of the present study was to enhance the solubility and dissolution rate of a poorly water soluble drug by forming inclusion complexes. Irbesartan was used as a model drug to evaluate its release characteristics from the formulations. The phase solubility studies of Irbesartan were conducted in the presence of various concentrations of β-CD and HP β-CD. ΔG_tr⁰ values were all negative for the carriers at various concentrations, indicating the spontaneous nature of drug's solubilization, and it decreased with an increase in its concentration, demonstrating that the reaction became more favorable as the concentration of carrier increased. The drug solubility increased linearly with increasing polymer concentration indicative of the A_L type of solubility phase diagram. Inclusion complexes of Irbesartan were prepared by kneading technique in various concentrations of drug: carrier. The dissolution profiles of the complexes were compared with those of the pure drug. All the inclusion complexes exhibited higher rates of dissolution values than Irbesartan pure drug and corresponding physical mixtures. Characterization of the solid dispersions was carried out by Differential Scanning Calorimetry (DSC) and Fourier Transform Infra-Red spectroscopy (FTIR).