Development of glyburide fast-dissolving tablets based on the combined use of cyclodextrins and polymers

Commercial tablets of glyburide exhibit unsatisfactory dissolution profiles and, consequently, problems of bioinequivalence and poor bioavailability. The aim of this work was to develop glyburide fast-dissolving tablets by exploiting the solubilizing effect of different cyclodextrins (CDs), alone or in combination with hydrophilic polymers. Drug-CD and drug-CD-polymer systems, prepared by different techniques, were characterized by differential scanning calorimetry (DSC), X-ray diffractometry, and Fourier transform infra-red (FT-IR) spectroscopy. Tablets containing binary and ternary systems were prepared by direct compression and evaluated for technological properties and dissolution behavior in comparison with a reference formulation containing the plain drug. A significant improvement of the drug dissolution profile was achieved from tablets containing drug-CD systems (coevaporated products doubled drug dissolution efficiency [DE]), but 100% drug dissolution was never reached. Better results were obtained with ternary systems. In particular, polyvinylpyrrolidone (PVP) emerged as the most effective polymer, and tablets with drug-PVP-hydroxypropyl-CD coevaporated products showed the best dissolution profiles, reaching 100% dissolved drug within only 15 min.