Investigation and Physicochemical Characterization of Binary Febuxostat- Sulfobutyl Ether β -Cyclodextrin Inclusion Complexes

Background: Febuxostat (FBX) a non-purine, xanthine oxidase inhibitor that is commonly indicated for the treatment of chronic gout. Yet, it is suffering from limited application as it belongs to The BCS II class that exhibit poor solubility. The aim of this study was to explore the impact of complexation between Febuxostat (FBX) and Sulfobutylether beta-cyclodextrin (SBE-β-CD) on physicochemical properties of FBX and its dissolution behavior. Methods: Different batches of inclusion complexes were formulated using various drug to polymer ratios (1:1, 1:3, and 1:5). The complexes were formulated with SBE-β-CD via four different techniques (physical mixture, kneading method, solvent evaporation and freeze drying). The inclusion complexes were examined by Fourier transformation infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), Differential scanning calorimetry (DSC), and Particle size analysis. The dissolution of different formulated FBX complexes was also studied. Results: The FTIR and DSC results suggested that FBX was incorporated inside the core of SBE-βCD to give inclusion complexes. In comparison to the other techniques, inclusion complex produced by freeze drying using SBE-βCD (1:5 ratio of drug to polymer) produced significantly higher Inclusion Efficiency (IE %). Moreover, the FBX- SBE-β-CD inclusion complex displayed higher aqueous solubility compared with free FBX, suggesting its potential application in pharmaceutical formulations. Conclusion: Freeze drying technique had successfully formed a binary system complex between FBX and SBE-βCD with better dissolution behavior. For further improvement of inclusion efficiency, investigation of a ternary complex system is highly recommended in future studies.