Formulation and Physicochemical Characterization of Glibenclamide Solid Dispersion Using Various Carriers

Aims: Glibenclamide is an oral hypoglycemic agent exhibits inadequate aqueous solubility resulting in poor and unpredictable bioavailability. The study was designed to enhance the solubility and dissolution of glibenclamide by solid dispersion. Place and Duration of Study: Department of Pharmacy, University of Rajshahi, Bangladesh between June 2017 and July 2018. Methodology: Solid dispersions of glibenclamide were prepared by solvent evaporation technique using mixture of PEG-8000, sodium citrate, HPMC as additives in different ratios and subsequently, in-vitro dissolution studies were performed. The characterization of solid dispersions was done by Differential Scanning Calorimetry, Powder X-ray Diffractometer, Fourier Transform Infrared Spectroscopy and Scanning Electron Microscope. Results: Out of twelve formulations, the GCHP-4 composed of glibenclamide: HPMC: Na-citrate: PEG-8000 1:1:1:1) demonstrated highest percentage of yield (87.76%) and encapsulation efficiency (95.68%). The maximum dissolution of glibenclamide obtained from GCHP-4 (3.34 µg/ml), which was 5.2-fold higher than that of pure glibenclamide (0.64 µg/ml) at 120 min. The mechanism of increased solubility of glibenclamide from solid dispersion might be resulted due to the conversion of its crystalline form into amorphous state and no interaction between drug and carriers which was confirmed by differential scanning calorimetry and fourier transform infrared spectroscopy respectively. Conclusion: The dissolution rate of glibenclamide was greatly increased when loaded in solid dispersions which might be responsible for the improvement of its bioavailability in aqueous medium.