Abstract
Sustained-release gastroretentive floating matrix tablets of cephradine were prepared for better patient compliance. Eight different tablets were prepared by using two natural polymers, psyllium husk powder (F1-F4) and xanthan gum (F5-F8), through the wet granulation technique. These tablets were characterized by pre- and postcompression analysis, Fourier transform infrared spectroscopy, swelling index study, in vitro buoyancy and dissolution study. Data were analyzed by model-dependent and model-independent analysis to devise the release mechanisms. The polymers exhibited excellent sustained-release behavior as well as binding characteristics. Pre- and postcompression parameters were observed in the specified official pharmacopoeia range. The drug contents of all the formulations were found in the range 95.52-99.63%. No chemical interaction was found between the drug and polymer. All formulations exhibited a good floating time - that is, >24 h - except F8, which remained buoyant for less than 1 h in simulated gastric fluid (pH 1.2). All of the formulations exhibited a direct relation between the swelling index and viscosity of polymer matrices. The significance of the wet granulation technique was indicated by the polymer action as a binding agent in wetting solution. From comparison of the two polymers, psyllium husk powder efficiently retarded the drug release owing to its high gelatinous swollen mass.