Investigation of inclusion behaviour of gefitinib with epichlorohydrin-β-cyclodextrin polymer: preparation of binary complex, stoichiometric determination and characterization

Gefitinib is anticancer drug which is sparingly soluble in water. This limits its dissolution and bioavailability. Binary inclusion complex of gefitinib with Epi-β-CD was prepared by freeze-drying method. Stoichiometric ratio of 1:1 M was established by continuous variation (Job's) plot. The stability constant of complex as determined by phase solubility study was found to be 15,871.3 M−1. Complex was characterized by FTIR, DSC, DTA and dissolution study. Results revealed that in complex the drug no longer exist in crystalline state and is converted into amorphous form; which shows higher dissolution efficiency as compared to crystalline drug. The solubilizing efficiency for freeze dried complex was found to be 175.57 and the relative drug crystallinity degree was 87.91% as estimated by thermal analysis. Complexation led to decrease in surface tension; from 54.8 dynes/cm (pure gefitinib) to 40.3 dynes/cm (FD complex) due to adsorption phenomenon. The results obtained in this study confirmed that complexation of gefitinib with Epi-β-CD is a prominent approach and suitable tool for tailoring the issue related to its delivery and can be explored for development of an effective delivery system.