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.
Keywords:
Gastroretentive, Porous hydrogels, Chitosan, Swelling,
Rosiglitazone.
