Binary inclusion complexes of diflunisal with β-cyclodextrin and hydroxypropyl-β-cyclodextrin: Preparation and characterization

Low aqueous solubility and bioavailability is the limiting factor to achieve desired therapeutic efficacy for variety of new and existing drug moieties. The goal of the present study was to explore the effects of beta-cyclodextrin (beta CD) and hydroxypropyl-beta-cyclodextrin (HP beta CD) on the solubility and dissolution profile of diflunisal (DIF) prepared by using two different methods (physical mixing and solvent evaporation) at DIF-cyclodextrins weight ratios of 1:1, 1:2 and 1:4. The phase solubility studies demonstrated that DIF solubility increased proportionally with an increase in beta CD and HP beta CD concentration. The inclusion complexes were subjected to characterization of scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and X-ray diffractometry (XRD). Solvent evaporation yielded higher DIF solubility than physical mixing method. HP beta CD-DIF inclusion complexes yielded higher dissolution profile than beta CD complexes when prepared under same experimental design. FTIR, DSC and XRD confirmed the successful inclusion of DIF into cyclodextrin (beta CD/HP beta CD) by both preparation methods with enhanced water solubility and drug release in comparison with pure drug.