Water soluble binary and ternary complexes of diosmin with β-cyclodextrin: Spectroscopic characterization, release studies and anti-oxidant activity

With an attempt to improve the solubility of poorly water-soluble bioactive compound diosmin, its inclusion complexation was investigated with β-cyclodextrin (β-CD) in the presence and/or absence of ternary component, hydroxypropyl methyl cellulose (HPMC) and polyethylene glycol 6000 (PEG 6000). The complexes of diosmin were prepared by kneading technique. Phase solubility studies confirmed a stoichiometry of 1:1 (diosmin:β-CD) molar ratio with an AL-type of phase solubility curve. The stability constants and complexation efficiency of binary systems were significantly improved in the presence of ternary components HPMC and PEG 6000. The formation of inclusion complexes were confirmed by FTIR, powder XRD, DSC, SEM and 1H NMR spectral analyses. In vitro drug release studies and anti-oxidant activity showed promising results when diosmin was complexed in binary and/or ternary system. These results indicated the suitability of β-CD in enhancing the solubility and in vitro bioactivity of diosmin.