Development of a gastroretentive drug delivery system based on superporous hydrogel

Abstract

Purpose: The aim of this work was to synthesize superporous hydrogels of rosiglitazone using chitosan and to study its swelling behaviour for application as a gastroretentive drug delivery system. Methods: Chitosan superporous hydrogels were synthesized using glyoxal as a crosslinking agent by gas blowing method. The effect of pH and ionic strength on the swelling ratio was determined. Swelling reversibility studies were also carried out. Fourier transform infrared (FTIR) analysis was undertaken to characterize the superporous hydrogels while dissolution studies were carried out to assess release characteristics. Results: Swelling was highly dependent on the extent of crosslinking. The higher the amount of crosslinking agent, the lower the swelling ratio. Higher ionic strength in pH 1.2 solution led to a decrease in swelling ratio. The superporous hydrogels were highly sensitive to pH of swelling medium, and showed reversible swelling and de-swelling behaviour while still maintaining their mechanical stability. Apparent density was dependent on the volume of the superporous hydrogels and decreased with increasing crosslink density. Degradation kinetics showed that chitosan superporous hydrogels had good water retention capability. Drug release was inversely related to the amount of crosslinking agent and fitted best to the Korsmeyer-Peppas model. Conclusion: The studies showed that chitosan-based superporous hydrogels can be used as a gastroretentive drug delivery system in view of their swelling characteristics in acidic pH. © Pharmacotherapy Group, Faculty of Pharmacy, University of Benin, Benin City, 300001 Nigeria.